[PATCH v26 00/25] LSM: Module stacking for AppArmor

[PATCH v26 00/25] LSM: Module stacking for AppArmor

[Casey Schaufler]

This patchset provides the changes required for
the AppArmor security module to stack safely with any other.

v26: Rebase to 5.13-rc1
     Include the landlock security module.
     Accomodate change from security_task_getsecid() to
     security_task_getsecid_obj() and security_task_getsecid_subj().
v25: Rebase to 5.12-rc2
     Incorporate feedback from v24
     - The IMA team suggested improvements to the integrity rule
       processing.
v24: Rebase to 5.11-rc1
     Incorporate feedback from v23
     - Address the IMA team's concerns about "label collisions".
       A label collision occurs when there is ambiguity about
       which of multiple LSMs is being targeted in the definition
       of an integrity check rule.  A system with Smack and
       AppArmor would be unable to distinguish which LSM is
       important to an integrity rule referrencing the label
       "unconfined" as that label is meaningful to both.
       Provide a boot option to specify which LSM will be used in
       IMA rules when multiple LSMs are present. (patch 04)
       Pull LSM "slot" identification from later audit patches in
       in support of this (patch 03).
     - Pick up a few audit events that need to include supplimental
       subject context records that had been missed in the
       previous version.
v23: Rebase to 5.10-rc4
     Incorporate feedback from v22
     - Change /proc/*/attr/display to /proc/*/attr/interface_lsm to
       make the purpose clearer. (patch 0012)
     - Include ABI documentation. (patch 0012, 0022)
     - Introduce LSM documentation updates with the patches where
       the interfaces are added rather than at the end. (patch 0012, 0022)
     Include more maintainers and mail lists in To: and Cc: directives.
v22: Rebase to 5.10-rc1
v21: Rebase to 5.9-rc4
     Incorporate feedback from v20
     - Further revert UDS SO_PEERSEC to use scaffolding around
       the interfaces that use lsmblobs and store only a single
       secid. The possibility of multiple security modules
       requiring data here is still a future problem.
     - Incorporate Richard Guy Briggs' non-syscall auxiliary
       records patch (patch 0019-0021) in place of my "supplimental"
       records implementation. [I'm not sure I've given proper
       attestation. I will correct as appropriate]
v20: Rebase to 5.9-rc1
     Change the BPF security module to use the lsmblob data. (patch 0002)
     Repair length logic in subject label processing (patch 0015)
     Handle -EINVAL from the empty BPF setprocattr hook (patch 0020)
     Correct length processing in append_ctx() (patch 0022)
v19: Rebase to 5.8-rc6
     Incorporate feedback from v18
     - Revert UDS SO_PEERSEC implementation to use lsmblobs
       directly, rather than allocating as needed. The correct
       treatment of out-of-memory conditions in the later case
       is difficult to define. (patch 0005)
     - Use a size_t in append_ctx() (patch 0021)
     - Fix a memory leak when creating compound contexts. (patch 0021)
     Fix build error when CONFIG_SECURITY isn't set (patch 0013)
     Fix build error when CONFIG_SECURITY isn't set (patch 0020)
     Fix build error when CONFIG_SECURITY isn't set (patch 0021)
v18: Rebase to 5.8-rc3
     Incorporate feedback from v17
     - Null pointer checking in UDS (patch 0005)
     Match changes in IMA code (patch 0012)
     Fix the behavior of LSM context supplimental audit
     records so that there's always exactly one when it's
     appropriate for there to be one. This is a substantial
     change that requires extention of the audit_context beyond
     syscall events. (patch 0020)
v17: Rebase to 5.7-rc4
v16: Rebase to 5.6
     Incorporate feedback from v15 - Thanks Stephen, Mimi and Paul
     - Generally improve commit messages WRT scaffolding
     - Comment ima_lsm_isset() (patch 0002)
     - Some question may remain on IMA warning (patch 0002)
     - Mark lsm_slot as __lsm_ro_after_init not __init_data (patch 0002)
     - Change name of lsmblob variable in ima_match_rules() (patch 0003)
     - Instead of putting a struct lsmblob into the unix_skb_parms
       structure put a pointer to an allocated instance. There is
       currently only space for 5 u32's in unix_skb_parms and it is
       likely to get even tighter. Fortunately, the lifecycle
       management of the allocated lsmblob is simple. (patch 0005)
     - Dropped Acks due to the above change (patch 0005)
     - Improved commentary on secmark labeling scaffolding. (patch 0006)
     - Reduced secmark related labeling scaffolding. (patch 0006)
     - Replace use of the zeroth entry of an lsmblob in scaffolding
       with a function lsmblob_value() to hopefully make it less
       obscure. (patch 0006)
     - Convert security_secmark_relabel_packet to use lsmblob as
       this reduces much of the most contentious scaffolding. (patch 0006)
     - Dropped Acks due to the above change (patch 0006)
     - Added BUILD_BUG_ON() for CIPSO tag 6. (patch 0018)
     - Reworked audit subject information. Instead of adding fields in
       the middle of existing records add a new record to the event. When
       a separate record is required use subj="?". (patch 0020)
     - Dropped Acks due to the above change (patch 0020)
     - Reworked audit object information. Instead of adding fields in
       the middle of existing records add a new record to the event. When
       a separate record is required use obj="?". (patch 0021)
     - Dropped Acks due to the above change (patch 0021)
     - Enhanced documentation (patch 0022)
     - Removed unnecessary error code check in security_getprocattr()
       (patch 0021)
v15: Rebase to 5.6-rc1
     - Revise IMA data use (patch 0002)
     Incorporate feedback from v14
     - Fix lockdown module registration naming (patch 0002)
     - Revise how /proc/self/attr/context is gathered. (patch 0022)
     - Revise access modes on /proc/self/attr/context. (patch 0022)
     - Revise documentation on LSM external interfaces. (patch 0022)
v14: Rebase to 5.5-rc5
     Incorporate feedback from v13
     - Use an array of audit rules (patch 0002)
     - Significant change, removed Acks (patch 0002)
     - Remove unneeded include (patch 0013)
     - Use context.len correctly (patch 0015)
     - Reorder code to be more sensible (patch 0016)
     - Drop SO_PEERCONTEXT as it's not needed yet (patch 0023)
v13: Rebase to 5.5-rc2
     Incorporate feedback from v12
     - Print lsmblob size with %z (Patch 0002)
     - Convert lockdown LSM initialization. (Patch 0002)
     - Restore error check in nft_secmark_compute_secid (Patch 0006)
     - Correct blob scaffolding in ima_must_appraise() (Patch 0009)
     - Make security_setprocattr() clearer (Patch 0013)
     - Use lsm_task_display more widely (Patch 0013)
     - Use passed size in lsmcontext_init() (Patch 0014)
     - Don't add a smack_release_secctx() hook (Patch 0014)
     - Don't print warning in security_release_secctx() (Patch 0014)
     - Don't duplicate the label in nfs4_label_init_security() (Patch 0016)
     - Remove reviewed-by as code has significant change (Patch 0016)
     - Send the entire lsmblob for Tag 6 (Patch 0019)
     - Fix description of socket_getpeersec_stream parameters (Patch 0023)
     - Retain LSMBLOB_FIRST. What was I thinking? (Patch 0023)
     - Add compound context to LSM documentation (Patch 0023)
v12: Rebase to 5.5-rc1
     Fixed a couple of incorrect contractions in the text.
v11: Rebase to 5.4-rc6
     Incorporate feedback from v10
     - Disambiguate reading /proc/.../attr/display by restricting
       all use of the interface to the current process.
     - Fix a merge error in AppArmor's display attribute check
v10: Ask the security modules if the display can be changed.
v9: There is no version 9
v8: Incorporate feedback from v7
    - Minor clean-up in display value management
    - refactor "compound" context creation to use a common
      append_ctx() function.
v7: Incorporate feedback from v6
    - Make setting the display a privileged operation. The
      availability of compound contexts reduces the need for
      setting the display.
v6: Incorporate feedback from v5
    - Add subj_<lsm>= and obj_<lsm>= fields to audit records
    - Add /proc/.../attr/context to get the full context in
      lsmname\0value\0... format as suggested by Simon McVittie
    - Add SO_PEERCONTEXT for getsockopt() to get the full context
      in the same format, also suggested by Simon McVittie.
    - Add /sys/kernel/security/lsm_display_default to provide
      the display default value.
v5: Incorporate feedback from v4
    - Initialize the lsmcontext in security_secid_to_secctx()
    - Clear the lsmcontext in all security_release_secctx() cases
    - Don't use the "display" on strictly internal context
      interfaces.
    - The SELinux binder hooks check for cases where the context
      "display" isn't compatible with SELinux.
v4: Incorporate feedback from v3
    - Mark new lsm_<blob>_alloc functions static
    - Replace the lsm and slot fields of the security_hook_list
      with a pointer to a LSM allocated lsm_id structure. The
      LSM identifies if it needs a slot explicitly. Use the
      lsm_id rather than make security_add_hooks return the
      slot value.
    - Validate slot values used in security.c
    - Reworked the "display" process attribute handling so that
      it works right and doesn't use goofy list processing.
    - fix display value check in dentry_init_security
    - Replace audit_log of secids with '?' instead of deleting
      the audit log
v3: Incorporate feedback from v2
    - Make lsmblob parameter and variable names more
      meaningful, changing "le" and "l" to "blob".
    - Improve consistency of constant naming.
    - Do more sanity checking during LSM initialization.
    - Be a bit clearer about what is temporary scaffolding.
    - Rather than clutter security_getpeersec_dgram with
      otherwise unnecessary checks remove the apparmor
      stub, which does nothing useful.

Patch 01 moves management of the sock security blob
from the individual modules to the infrastructure.

Patches 02-03 introduce a structure "lsmblob" that will gradually
replace the "secid" as a shorthand for security module information.
At this point lsmblob contains an array of u32 secids, one "slot"
for each of the security modules compiled into the kernel that
used secids. A "slot" is allocated when a security module requests
one.

Patch 04 provides mechanism for the IMA subsystem to identify
explicitly which LSM is subject to IMA policy. This includes
a boot option for specifying the default and an additional option
in IMA rules "lsm=".

Patches 05-13 change LSM interfaces to use the lsmblob instead
of secids. It is important that the lsmblob be a fixed size entity
that does not have to be allocated. Several of the places
where it is used would have performance and/or locking
issues with dynamic allocation.

Patch 14 provides a mechanism for a process to identify which
security module's hooks should be used when displaying or
converting a security context string.  A new interface
/proc/self/attr/interface_lsm contains the name of the security
module to show. Reading from this file will present the name of
the module, while writing to it will set the value. Only names
of active security modules are accepted. Internally, the name
is translated to the appropriate "slot" number for the module
which is then stored in the task security blob. Setting the
display requires that all modules using the /proc interfaces
allow the transition. The interface LSM of other processess
can be neither read nor written. All suggested cases for
reading the interface LSM of a different process have race
conditions.

Patch 15 Starts the process of changing how a security
context is represented. Since it is possible for a
security context to have been generated by more than one
security module it is now necessary to note which module
created a security context so that the correct "release"
hook can be called. There are several places where the
module that created a security context cannot be inferred.

This is achieved by introducing a "lsmcontext" structure
which contains the context string, its length and the
"slot" number of the security module that created it.
The security_release_secctx() interface is changed,
replacing the (string,len) pointer pair with a lsmcontext
pointer.

Patches 16-18 convert the security interfaces from
(string,len) pointer pairs to a lsmcontext pointer.
The slot number identifying the creating module is
added by the infrastructure. Where the security context
is stored for extended periods the data type is changed.

The Netlabel code is converted to save lsmblob structures
instead of secids in Patch 19. This is not strictly
necessary as there can only be one security module that
uses Netlabel at this point. Using a lsmblob is much
cleaner, as the interfaces that use the data have all
been converted.

Patch 20 adds checks to the binder hooks which verify
that both ends of a transaction use the same interface LSM.

Patches 21-23 add addition audit records for subject and
object LSM data when there are multiple security modules
with such data. The AUDIT_MAC_TASK_CONTEXTS record is used
in conjuction with a "subj=?" field to identify the subject
data. The AUDIT_MAC_OBJ_CONTEXTS record is used in conjuction
with a "obj=?" field to identify the object data.  The
AUDIT_MAC_TASK_CONTEXTS record identifies the security module
with the data: "subj_selinux=xyz_t subj_apparmor=abc". The
AUDIT_MAC_OBJ_CONTEXTS record identifies the security module
with the data: "obj_selinux=xyz_t obj_apparmor=abc".  While
AUDIT_MAC_TASK_CONTEXTS records will always contain an entry
for each possible security modules, AUDIT_MAC_OBJ_CONTEXTS
records will only contain entries for security modules for
which the object in question has data.

An example of the MAC_TASK_CONTEXTS (1420) record is:

    type=UNKNOWN[1420]
    msg=audit(1600880931.832:113)
    subj_apparmor==unconfined
    subj_smack=_

An example of the MAC_OBJ_CONTEXTS (1421) record is:

    type=UNKNOWN[1421]
    msg=audit(1601152467.009:1050):
    obj_selinux=unconfined_u:object_r:user_home_t:s0

Patch 24 adds a new interface for getting the compound security
contexts, /proc/self/attr/context.  An example of the content
of this file is:

    selinux\0one_u:one_r:one_t:s0-s0:c0.c1023\0apparmor\0unconfined\0

Finally, with all interference on the AppArmor hooks removed,
Patch 25 removes the exclusive bit from AppArmor. An unnecessary
stub hook was also removed.

The Ubuntu project is using an earlier version of this patchset in
their distribution to enable stacking for containers.

Performance measurements to date have the change within the "noise".
The sockperf and dbench results are on the order of 0.2% to 0.8%
difference, with better performance being as common as worse. The
benchmarks were run with AppArmor and Smack on Ubuntu.

https://github.com/cschaufler/lsm-stacking.git#stack-5.13-rc1-v26

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>


Casey Schaufler (25):
  LSM: Infrastructure management of the sock security
  LSM: Add the lsmblob data structure.
  LSM: provide lsm name and id slot mappings
  IMA: avoid label collisions with stacked LSMs
  LSM: Use lsmblob in security_audit_rule_match
  LSM: Use lsmblob in security_kernel_act_as
  LSM: Use lsmblob in security_secctx_to_secid
  LSM: Use lsmblob in security_secid_to_secctx
  LSM: Use lsmblob in security_ipc_getsecid
  LSM: Use lsmblob in security_task_getsecid
  LSM: Use lsmblob in security_inode_getsecid
  LSM: Use lsmblob in security_cred_getsecid
  IMA: Change internal interfaces to use lsmblobs
  LSM: Specify which LSM to display
  LSM: Ensure the correct LSM context releaser
  LSM: Use lsmcontext in security_secid_to_secctx
  LSM: Use lsmcontext in security_inode_getsecctx
  LSM: security_secid_to_secctx in netlink netfilter
  NET: Store LSM netlabel data in a lsmblob
  LSM: Verify LSM display sanity in binder
  audit: add support for non-syscall auxiliary records
  Audit: Add new record for multiple process LSM  attributes
  Audit: Add a new record for multiple object LSM  attributes
  LSM: Add /proc attr entry for full LSM context
  AppArmor: Remove the exclusive flag

 Documentation/ABI/testing/ima_policy          |   8 +-
 Documentation/ABI/testing/procfs-attr-context |  14 +
 .../ABI/testing/procfs-attr-lsm_display       |  22 +
 Documentation/security/lsm.rst                |  28 +
 drivers/android/binder.c                      |  26 +-
 fs/ceph/xattr.c                               |   6 +-
 fs/nfs/nfs4proc.c                             |   8 +-
 fs/nfsd/nfs4xdr.c                             |  20 +-
 fs/proc/base.c                                |   2 +
 include/linux/audit.h                         |  43 +-
 include/linux/cred.h                          |   3 +-
 include/linux/lsm_hooks.h                     |  36 +-
 include/linux/security.h                      | 192 +++++-
 include/net/netlabel.h                        |  11 +-
 include/net/scm.h                             |  15 +-
 include/net/xfrm.h                            |  13 +-
 include/uapi/linux/audit.h                    |   2 +
 kernel/audit.c                                | 175 ++++--
 kernel/audit.h                                |  11 +-
 kernel/auditfilter.c                          |  36 +-
 kernel/auditsc.c                              | 193 +++---
 kernel/cred.c                                 |  12 +-
 net/ipv4/cipso_ipv4.c                         |  26 +-
 net/ipv4/ip_sockglue.c                        |  12 +-
 net/netfilter/nf_conntrack_netlink.c          |  24 +-
 net/netfilter/nf_conntrack_standalone.c       |  11 +-
 net/netfilter/nfnetlink_queue.c               |  38 +-
 net/netfilter/nft_meta.c                      |  10 +-
 net/netfilter/xt_SECMARK.c                    |   7 +-
 net/netlabel/netlabel_domainhash.c            |   4 +-
 net/netlabel/netlabel_kapi.c                  |   6 +-
 net/netlabel/netlabel_unlabeled.c             | 106 ++--
 net/netlabel/netlabel_unlabeled.h             |   2 +-
 net/netlabel/netlabel_user.c                  |  23 +-
 net/netlabel/netlabel_user.h                  |   2 +-
 net/xfrm/xfrm_policy.c                        |  10 +-
 net/xfrm/xfrm_state.c                         |  20 +-
 security/apparmor/include/apparmor.h          |   3 +-
 security/apparmor/include/net.h               |   6 +-
 security/apparmor/include/procattr.h          |   2 +-
 security/apparmor/lsm.c                       | 105 ++--
 security/apparmor/procattr.c                  |  22 +-
 security/bpf/hooks.c                          |  12 +-
 security/commoncap.c                          |   7 +-
 security/integrity/ima/ima.h                  |  10 +-
 security/integrity/ima/ima_api.c              |  13 +-
 security/integrity/ima/ima_appraise.c         |   9 +-
 security/integrity/ima/ima_main.c             |  60 +-
 security/integrity/ima/ima_policy.c           |  87 ++-
 security/integrity/integrity_audit.c          |   6 +-
 security/landlock/cred.c                      |   2 +-
 security/landlock/fs.c                        |   2 +-
 security/landlock/ptrace.c                    |   2 +-
 security/landlock/setup.c                     |   4 +
 security/landlock/setup.h                     |   1 +
 security/loadpin/loadpin.c                    |   8 +-
 security/lockdown/lockdown.c                  |   7 +-
 security/safesetid/lsm.c                      |   8 +-
 security/security.c                           | 574 ++++++++++++++++--
 security/selinux/hooks.c                      |  99 +--
 security/selinux/include/classmap.h           |   2 +-
 security/selinux/include/objsec.h             |   5 +
 security/selinux/include/security.h           |   1 +
 security/selinux/netlabel.c                   |  25 +-
 security/selinux/ss/services.c                |   4 +-
 security/smack/smack.h                        |   6 +
 security/smack/smack_access.c                 |   2 +-
 security/smack/smack_lsm.c                    |  91 +--
 security/smack/smack_netfilter.c              |   8 +-
 security/smack/smackfs.c                      |  13 +-
 security/tomoyo/tomoyo.c                      |   8 +-
 security/yama/yama_lsm.c                      |   7 +-
 72 files changed, 1758 insertions(+), 640 deletions(-)
 create mode 100644 Documentation/ABI/testing/procfs-attr-context
 create mode 100644 Documentation/ABI/testing/procfs-attr-lsm_display

-- 
2.29.2

[PATCH v26 01/25] LSM: Infrastructure management of the sock security

[Casey Schaufler]

Move management of the sock->sk_security blob out
of the individual security modules and into the security
infrastructure. Instead of allocating the blobs from within
the modules the modules tell the infrastructure how much
space is required, and the space is allocated there.

Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/lsm_hooks.h         |  1 +
 security/apparmor/include/net.h   |  6 ++-
 security/apparmor/lsm.c           | 38 ++++-----------
 security/security.c               | 36 +++++++++++++-
 security/selinux/hooks.c          | 78 +++++++++++++++----------------
 security/selinux/include/objsec.h |  5 ++
 security/selinux/netlabel.c       | 23 ++++-----
 security/smack/smack.h            |  5 ++
 security/smack/smack_lsm.c        | 66 ++++++++++++--------------
 security/smack/smack_netfilter.c  |  8 ++--
 10 files changed, 145 insertions(+), 121 deletions(-)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 5c4c5c0602cb..afd3b16875b0 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1588,6 +1588,7 @@ struct lsm_blob_sizes {
 	int	lbs_cred;
 	int	lbs_file;
 	int	lbs_inode;
+	int	lbs_sock;
 	int	lbs_superblock;
 	int	lbs_ipc;
 	int	lbs_msg_msg;
diff --git a/security/apparmor/include/net.h b/security/apparmor/include/net.h
index aadb4b29fb66..fac8999ba7a3 100644
--- a/security/apparmor/include/net.h
+++ b/security/apparmor/include/net.h
@@ -51,7 +51,11 @@ struct aa_sk_ctx {
 	struct aa_label *peer;
 };
 
-#define SK_CTX(X) ((X)->sk_security)
+static inline struct aa_sk_ctx *aa_sock(const struct sock *sk)
+{
+	return sk->sk_security + apparmor_blob_sizes.lbs_sock;
+}
+
 #define SOCK_ctx(X) SOCK_INODE(X)->i_security
 #define DEFINE_AUDIT_NET(NAME, OP, SK, F, T, P)				  \
 	struct lsm_network_audit NAME ## _net = { .sk = (SK),		  \
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index f72406fe1bf2..4113516fb62e 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -775,33 +775,15 @@ static int apparmor_task_kill(struct task_struct *target, struct kernel_siginfo
 	return error;
 }
 
-/**
- * apparmor_sk_alloc_security - allocate and attach the sk_security field
- */
-static int apparmor_sk_alloc_security(struct sock *sk, int family, gfp_t flags)
-{
-	struct aa_sk_ctx *ctx;
-
-	ctx = kzalloc(sizeof(*ctx), flags);
-	if (!ctx)
-		return -ENOMEM;
-
-	SK_CTX(sk) = ctx;
-
-	return 0;
-}
-
 /**
  * apparmor_sk_free_security - free the sk_security field
  */
 static void apparmor_sk_free_security(struct sock *sk)
 {
-	struct aa_sk_ctx *ctx = SK_CTX(sk);
+	struct aa_sk_ctx *ctx = aa_sock(sk);
 
-	SK_CTX(sk) = NULL;
 	aa_put_label(ctx->label);
 	aa_put_label(ctx->peer);
-	kfree(ctx);
 }
 
 /**
@@ -810,8 +792,8 @@ static void apparmor_sk_free_security(struct sock *sk)
 static void apparmor_sk_clone_security(const struct sock *sk,
 				       struct sock *newsk)
 {
-	struct aa_sk_ctx *ctx = SK_CTX(sk);
-	struct aa_sk_ctx *new = SK_CTX(newsk);
+	struct aa_sk_ctx *ctx = aa_sock(sk);
+	struct aa_sk_ctx *new = aa_sock(newsk);
 
 	if (new->label)
 		aa_put_label(new->label);
@@ -867,7 +849,7 @@ static int apparmor_socket_post_create(struct socket *sock, int family,
 		label = aa_get_current_label();
 
 	if (sock->sk) {
-		struct aa_sk_ctx *ctx = SK_CTX(sock->sk);
+		struct aa_sk_ctx *ctx = aa_sock(sock->sk);
 
 		aa_put_label(ctx->label);
 		ctx->label = aa_get_label(label);
@@ -1052,7 +1034,7 @@ static int apparmor_socket_shutdown(struct socket *sock, int how)
  */
 static int apparmor_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 {
-	struct aa_sk_ctx *ctx = SK_CTX(sk);
+	struct aa_sk_ctx *ctx = aa_sock(sk);
 
 	if (!skb->secmark)
 		return 0;
@@ -1065,7 +1047,7 @@ static int apparmor_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 
 static struct aa_label *sk_peer_label(struct sock *sk)
 {
-	struct aa_sk_ctx *ctx = SK_CTX(sk);
+	struct aa_sk_ctx *ctx = aa_sock(sk);
 
 	if (ctx->peer)
 		return ctx->peer;
@@ -1149,7 +1131,7 @@ static int apparmor_socket_getpeersec_dgram(struct socket *sock,
  */
 static void apparmor_sock_graft(struct sock *sk, struct socket *parent)
 {
-	struct aa_sk_ctx *ctx = SK_CTX(sk);
+	struct aa_sk_ctx *ctx = aa_sock(sk);
 
 	if (!ctx->label)
 		ctx->label = aa_get_current_label();
@@ -1159,7 +1141,7 @@ static void apparmor_sock_graft(struct sock *sk, struct socket *parent)
 static int apparmor_inet_conn_request(const struct sock *sk, struct sk_buff *skb,
 				      struct request_sock *req)
 {
-	struct aa_sk_ctx *ctx = SK_CTX(sk);
+	struct aa_sk_ctx *ctx = aa_sock(sk);
 
 	if (!skb->secmark)
 		return 0;
@@ -1176,6 +1158,7 @@ struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = {
 	.lbs_cred = sizeof(struct aa_task_ctx *),
 	.lbs_file = sizeof(struct aa_file_ctx),
 	.lbs_task = sizeof(struct aa_task_ctx),
+	.lbs_sock = sizeof(struct aa_sk_ctx),
 };
 
 static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
@@ -1212,7 +1195,6 @@ static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(getprocattr, apparmor_getprocattr),
 	LSM_HOOK_INIT(setprocattr, apparmor_setprocattr),
 
-	LSM_HOOK_INIT(sk_alloc_security, apparmor_sk_alloc_security),
 	LSM_HOOK_INIT(sk_free_security, apparmor_sk_free_security),
 	LSM_HOOK_INIT(sk_clone_security, apparmor_sk_clone_security),
 
@@ -1764,7 +1746,7 @@ static unsigned int apparmor_ip_postroute(void *priv,
 	if (sk == NULL)
 		return NF_ACCEPT;
 
-	ctx = SK_CTX(sk);
+	ctx = aa_sock(sk);
 	if (!apparmor_secmark_check(ctx->label, OP_SENDMSG, AA_MAY_SEND,
 				    skb->secmark, sk))
 		return NF_ACCEPT;
diff --git a/security/security.c b/security/security.c
index b38155b2de83..e12a7c463468 100644
--- a/security/security.c
+++ b/security/security.c
@@ -29,6 +29,7 @@
 #include <linux/string.h>
 #include <linux/msg.h>
 #include <net/flow.h>
+#include <net/sock.h>
 
 #define MAX_LSM_EVM_XATTR	2
 
@@ -203,6 +204,7 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed)
 	lsm_set_blob_size(&needed->lbs_inode, &blob_sizes.lbs_inode);
 	lsm_set_blob_size(&needed->lbs_ipc, &blob_sizes.lbs_ipc);
 	lsm_set_blob_size(&needed->lbs_msg_msg, &blob_sizes.lbs_msg_msg);
+	lsm_set_blob_size(&needed->lbs_sock, &blob_sizes.lbs_sock);
 	lsm_set_blob_size(&needed->lbs_superblock, &blob_sizes.lbs_superblock);
 	lsm_set_blob_size(&needed->lbs_task, &blob_sizes.lbs_task);
 }
@@ -339,6 +341,7 @@ static void __init ordered_lsm_init(void)
 	init_debug("inode blob size      = %d\n", blob_sizes.lbs_inode);
 	init_debug("ipc blob size        = %d\n", blob_sizes.lbs_ipc);
 	init_debug("msg_msg blob size    = %d\n", blob_sizes.lbs_msg_msg);
+	init_debug("sock blob size       = %d\n", blob_sizes.lbs_sock);
 	init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock);
 	init_debug("task blob size       = %d\n", blob_sizes.lbs_task);
 
@@ -658,6 +661,28 @@ static int lsm_msg_msg_alloc(struct msg_msg *mp)
 	return 0;
 }
 
+/**
+ * lsm_sock_alloc - allocate a composite sock blob
+ * @sock: the sock that needs a blob
+ * @priority: allocation mode
+ *
+ * Allocate the sock blob for all the modules
+ *
+ * Returns 0, or -ENOMEM if memory can't be allocated.
+ */
+static int lsm_sock_alloc(struct sock *sock, gfp_t priority)
+{
+	if (blob_sizes.lbs_sock == 0) {
+		sock->sk_security = NULL;
+		return 0;
+	}
+
+	sock->sk_security = kzalloc(blob_sizes.lbs_sock, priority);
+	if (sock->sk_security == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
 /**
  * lsm_early_task - during initialization allocate a composite task blob
  * @task: the task that needs a blob
@@ -2258,12 +2283,21 @@ EXPORT_SYMBOL(security_socket_getpeersec_dgram);
 
 int security_sk_alloc(struct sock *sk, int family, gfp_t priority)
 {
-	return call_int_hook(sk_alloc_security, 0, sk, family, priority);
+	int rc = lsm_sock_alloc(sk, priority);
+
+	if (unlikely(rc))
+		return rc;
+	rc = call_int_hook(sk_alloc_security, 0, sk, family, priority);
+	if (unlikely(rc))
+		security_sk_free(sk);
+	return rc;
 }
 
 void security_sk_free(struct sock *sk)
 {
 	call_void_hook(sk_free_security, sk);
+	kfree(sk->sk_security);
+	sk->sk_security = NULL;
 }
 
 void security_sk_clone(const struct sock *sk, struct sock *newsk)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index eaea837d89d1..84ddcec6322e 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4652,7 +4652,7 @@ static int socket_sockcreate_sid(const struct task_security_struct *tsec,
 
 static int sock_has_perm(struct sock *sk, u32 perms)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
 
@@ -4709,7 +4709,7 @@ static int selinux_socket_post_create(struct socket *sock, int family,
 	isec->initialized = LABEL_INITIALIZED;
 
 	if (sock->sk) {
-		sksec = sock->sk->sk_security;
+		sksec = selinux_sock(sock->sk);
 		sksec->sclass = sclass;
 		sksec->sid = sid;
 		/* Allows detection of the first association on this socket */
@@ -4725,8 +4725,8 @@ static int selinux_socket_post_create(struct socket *sock, int family,
 static int selinux_socket_socketpair(struct socket *socka,
 				     struct socket *sockb)
 {
-	struct sk_security_struct *sksec_a = socka->sk->sk_security;
-	struct sk_security_struct *sksec_b = sockb->sk->sk_security;
+	struct sk_security_struct *sksec_a = selinux_sock(socka->sk);
+	struct sk_security_struct *sksec_b = selinux_sock(sockb->sk);
 
 	sksec_a->peer_sid = sksec_b->sid;
 	sksec_b->peer_sid = sksec_a->sid;
@@ -4741,7 +4741,7 @@ static int selinux_socket_socketpair(struct socket *socka,
 static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen)
 {
 	struct sock *sk = sock->sk;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	u16 family;
 	int err;
 
@@ -4876,7 +4876,7 @@ static int selinux_socket_connect_helper(struct socket *sock,
 					 struct sockaddr *address, int addrlen)
 {
 	struct sock *sk = sock->sk;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	int err;
 
 	err = sock_has_perm(sk, SOCKET__CONNECT);
@@ -5055,9 +5055,9 @@ static int selinux_socket_unix_stream_connect(struct sock *sock,
 					      struct sock *other,
 					      struct sock *newsk)
 {
-	struct sk_security_struct *sksec_sock = sock->sk_security;
-	struct sk_security_struct *sksec_other = other->sk_security;
-	struct sk_security_struct *sksec_new = newsk->sk_security;
+	struct sk_security_struct *sksec_sock = selinux_sock(sock);
+	struct sk_security_struct *sksec_other = selinux_sock(other);
+	struct sk_security_struct *sksec_new = selinux_sock(newsk);
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
 	int err;
@@ -5089,8 +5089,8 @@ static int selinux_socket_unix_stream_connect(struct sock *sock,
 static int selinux_socket_unix_may_send(struct socket *sock,
 					struct socket *other)
 {
-	struct sk_security_struct *ssec = sock->sk->sk_security;
-	struct sk_security_struct *osec = other->sk->sk_security;
+	struct sk_security_struct *ssec = selinux_sock(sock->sk);
+	struct sk_security_struct *osec = selinux_sock(other->sk);
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
 
@@ -5132,7 +5132,7 @@ static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb,
 				       u16 family)
 {
 	int err = 0;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	u32 sk_sid = sksec->sid;
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
@@ -5165,7 +5165,7 @@ static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb,
 static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 {
 	int err;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	u16 family = sk->sk_family;
 	u32 sk_sid = sksec->sid;
 	struct common_audit_data ad;
@@ -5233,13 +5233,15 @@ static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 	return err;
 }
 
-static int selinux_socket_getpeersec_stream(struct socket *sock, char __user *optval,
-					    int __user *optlen, unsigned len)
+static int selinux_socket_getpeersec_stream(struct socket *sock,
+					    char __user *optval,
+					    int __user *optlen,
+					    unsigned int len)
 {
 	int err = 0;
 	char *scontext;
 	u32 scontext_len;
-	struct sk_security_struct *sksec = sock->sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sock->sk);
 	u32 peer_sid = SECSID_NULL;
 
 	if (sksec->sclass == SECCLASS_UNIX_STREAM_SOCKET ||
@@ -5299,34 +5301,27 @@ static int selinux_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *
 
 static int selinux_sk_alloc_security(struct sock *sk, int family, gfp_t priority)
 {
-	struct sk_security_struct *sksec;
-
-	sksec = kzalloc(sizeof(*sksec), priority);
-	if (!sksec)
-		return -ENOMEM;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	sksec->peer_sid = SECINITSID_UNLABELED;
 	sksec->sid = SECINITSID_UNLABELED;
 	sksec->sclass = SECCLASS_SOCKET;
 	selinux_netlbl_sk_security_reset(sksec);
-	sk->sk_security = sksec;
 
 	return 0;
 }
 
 static void selinux_sk_free_security(struct sock *sk)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
-	sk->sk_security = NULL;
 	selinux_netlbl_sk_security_free(sksec);
-	kfree(sksec);
 }
 
 static void selinux_sk_clone_security(const struct sock *sk, struct sock *newsk)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
-	struct sk_security_struct *newsksec = newsk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
+	struct sk_security_struct *newsksec = selinux_sock(newsk);
 
 	newsksec->sid = sksec->sid;
 	newsksec->peer_sid = sksec->peer_sid;
@@ -5340,7 +5335,7 @@ static void selinux_sk_getsecid(struct sock *sk, u32 *secid)
 	if (!sk)
 		*secid = SECINITSID_ANY_SOCKET;
 	else {
-		struct sk_security_struct *sksec = sk->sk_security;
+		struct sk_security_struct *sksec = selinux_sock(sk);
 
 		*secid = sksec->sid;
 	}
@@ -5350,7 +5345,7 @@ static void selinux_sock_graft(struct sock *sk, struct socket *parent)
 {
 	struct inode_security_struct *isec =
 		inode_security_novalidate(SOCK_INODE(parent));
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	if (sk->sk_family == PF_INET || sk->sk_family == PF_INET6 ||
 	    sk->sk_family == PF_UNIX)
@@ -5365,7 +5360,7 @@ static void selinux_sock_graft(struct sock *sk, struct socket *parent)
 static int selinux_sctp_assoc_request(struct sctp_endpoint *ep,
 				      struct sk_buff *skb)
 {
-	struct sk_security_struct *sksec = ep->base.sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(ep->base.sk);
 	struct common_audit_data ad;
 	struct lsm_network_audit net = {0,};
 	u8 peerlbl_active;
@@ -5516,8 +5511,8 @@ static int selinux_sctp_bind_connect(struct sock *sk, int optname,
 static void selinux_sctp_sk_clone(struct sctp_endpoint *ep, struct sock *sk,
 				  struct sock *newsk)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
-	struct sk_security_struct *newsksec = newsk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
+	struct sk_security_struct *newsksec = selinux_sock(newsk);
 
 	/* If policy does not support SECCLASS_SCTP_SOCKET then call
 	 * the non-sctp clone version.
@@ -5534,7 +5529,7 @@ static void selinux_sctp_sk_clone(struct sctp_endpoint *ep, struct sock *sk,
 static int selinux_inet_conn_request(const struct sock *sk, struct sk_buff *skb,
 				     struct request_sock *req)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	int err;
 	u16 family = req->rsk_ops->family;
 	u32 connsid;
@@ -5555,7 +5550,7 @@ static int selinux_inet_conn_request(const struct sock *sk, struct sk_buff *skb,
 static void selinux_inet_csk_clone(struct sock *newsk,
 				   const struct request_sock *req)
 {
-	struct sk_security_struct *newsksec = newsk->sk_security;
+	struct sk_security_struct *newsksec = selinux_sock(newsk);
 
 	newsksec->sid = req->secid;
 	newsksec->peer_sid = req->peer_secid;
@@ -5572,7 +5567,7 @@ static void selinux_inet_csk_clone(struct sock *newsk,
 static void selinux_inet_conn_established(struct sock *sk, struct sk_buff *skb)
 {
 	u16 family = sk->sk_family;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	/* handle mapped IPv4 packets arriving via IPv6 sockets */
 	if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
@@ -5656,7 +5651,7 @@ static int selinux_tun_dev_attach_queue(void *security)
 static int selinux_tun_dev_attach(struct sock *sk, void *security)
 {
 	struct tun_security_struct *tunsec = security;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	/* we don't currently perform any NetLabel based labeling here and it
 	 * isn't clear that we would want to do so anyway; while we could apply
@@ -5800,7 +5795,7 @@ static unsigned int selinux_ip_output(struct sk_buff *skb,
 			return NF_ACCEPT;
 
 		/* standard practice, label using the parent socket */
-		sksec = sk->sk_security;
+		sksec = selinux_sock(sk);
 		sid = sksec->sid;
 	} else
 		sid = SECINITSID_KERNEL;
@@ -5839,7 +5834,7 @@ static unsigned int selinux_ip_postroute_compat(struct sk_buff *skb,
 
 	if (sk == NULL)
 		return NF_ACCEPT;
-	sksec = sk->sk_security;
+	sksec = selinux_sock(sk);
 
 	ad.type = LSM_AUDIT_DATA_NET;
 	ad.u.net = &net;
@@ -5931,7 +5926,7 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb,
 		u32 skb_sid;
 		struct sk_security_struct *sksec;
 
-		sksec = sk->sk_security;
+		sksec = selinux_sock(sk);
 		if (selinux_skb_peerlbl_sid(skb, family, &skb_sid))
 			return NF_DROP;
 		/* At this point, if the returned skb peerlbl is SECSID_NULL
@@ -5960,7 +5955,7 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb,
 	} else {
 		/* Locally generated packet, fetch the security label from the
 		 * associated socket. */
-		struct sk_security_struct *sksec = sk->sk_security;
+		struct sk_security_struct *sksec = selinux_sock(sk);
 		peer_sid = sksec->sid;
 		secmark_perm = PACKET__SEND;
 	}
@@ -6025,7 +6020,7 @@ static int selinux_netlink_send(struct sock *sk, struct sk_buff *skb)
 	unsigned int data_len = skb->len;
 	unsigned char *data = skb->data;
 	struct nlmsghdr *nlh;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	u16 sclass = sksec->sclass;
 	u32 perm;
 
@@ -7051,6 +7046,7 @@ struct lsm_blob_sizes selinux_blob_sizes __lsm_ro_after_init = {
 	.lbs_inode = sizeof(struct inode_security_struct),
 	.lbs_ipc = sizeof(struct ipc_security_struct),
 	.lbs_msg_msg = sizeof(struct msg_security_struct),
+	.lbs_sock = sizeof(struct sk_security_struct),
 	.lbs_superblock = sizeof(struct superblock_security_struct),
 };
 
diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h
index 2953132408bf..007d1ae7ee27 100644
--- a/security/selinux/include/objsec.h
+++ b/security/selinux/include/objsec.h
@@ -194,4 +194,9 @@ static inline struct superblock_security_struct *selinux_superblock(
 	return superblock->s_security + selinux_blob_sizes.lbs_superblock;
 }
 
+static inline struct sk_security_struct *selinux_sock(const struct sock *sock)
+{
+	return sock->sk_security + selinux_blob_sizes.lbs_sock;
+}
+
 #endif /* _SELINUX_OBJSEC_H_ */
diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
index abaab7683840..6a94b31b5472 100644
--- a/security/selinux/netlabel.c
+++ b/security/selinux/netlabel.c
@@ -17,6 +17,7 @@
 #include <linux/gfp.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
+#include <linux/lsm_hooks.h>
 #include <net/sock.h>
 #include <net/netlabel.h>
 #include <net/ip.h>
@@ -67,7 +68,7 @@ static int selinux_netlbl_sidlookup_cached(struct sk_buff *skb,
 static struct netlbl_lsm_secattr *selinux_netlbl_sock_genattr(struct sock *sk)
 {
 	int rc;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr *secattr;
 
 	if (sksec->nlbl_secattr != NULL)
@@ -100,7 +101,7 @@ static struct netlbl_lsm_secattr *selinux_netlbl_sock_getattr(
 							const struct sock *sk,
 							u32 sid)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr *secattr = sksec->nlbl_secattr;
 
 	if (secattr == NULL)
@@ -235,7 +236,7 @@ int selinux_netlbl_skbuff_setsid(struct sk_buff *skb,
 	 * being labeled by it's parent socket, if it is just exit */
 	sk = skb_to_full_sk(skb);
 	if (sk != NULL) {
-		struct sk_security_struct *sksec = sk->sk_security;
+		struct sk_security_struct *sksec = selinux_sock(sk);
 
 		if (sksec->nlbl_state != NLBL_REQSKB)
 			return 0;
@@ -273,7 +274,7 @@ int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep,
 {
 	int rc;
 	struct netlbl_lsm_secattr secattr;
-	struct sk_security_struct *sksec = ep->base.sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(ep->base.sk);
 	struct sockaddr_in addr4;
 	struct sockaddr_in6 addr6;
 
@@ -352,7 +353,7 @@ int selinux_netlbl_inet_conn_request(struct request_sock *req, u16 family)
  */
 void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	if (family == PF_INET)
 		sksec->nlbl_state = NLBL_LABELED;
@@ -370,8 +371,8 @@ void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family)
  */
 void selinux_netlbl_sctp_sk_clone(struct sock *sk, struct sock *newsk)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
-	struct sk_security_struct *newsksec = newsk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
+	struct sk_security_struct *newsksec = selinux_sock(newsk);
 
 	newsksec->nlbl_state = sksec->nlbl_state;
 }
@@ -389,7 +390,7 @@ void selinux_netlbl_sctp_sk_clone(struct sock *sk, struct sock *newsk)
 int selinux_netlbl_socket_post_create(struct sock *sk, u16 family)
 {
 	int rc;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr *secattr;
 
 	if (family != PF_INET && family != PF_INET6)
@@ -504,7 +505,7 @@ int selinux_netlbl_socket_setsockopt(struct socket *sock,
 {
 	int rc = 0;
 	struct sock *sk = sock->sk;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr secattr;
 
 	if (selinux_netlbl_option(level, optname) &&
@@ -542,7 +543,7 @@ static int selinux_netlbl_socket_connect_helper(struct sock *sk,
 						struct sockaddr *addr)
 {
 	int rc;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr *secattr;
 
 	/* connected sockets are allowed to disconnect when the address family
@@ -581,7 +582,7 @@ static int selinux_netlbl_socket_connect_helper(struct sock *sk,
 int selinux_netlbl_socket_connect_locked(struct sock *sk,
 					 struct sockaddr *addr)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	if (sksec->nlbl_state != NLBL_REQSKB &&
 	    sksec->nlbl_state != NLBL_CONNLABELED)
diff --git a/security/smack/smack.h b/security/smack/smack.h
index c3cfbdf4944a..b5bdf947792f 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -363,6 +363,11 @@ static inline struct superblock_smack *smack_superblock(
 	return superblock->s_security + smack_blob_sizes.lbs_superblock;
 }
 
+static inline struct socket_smack *smack_sock(const struct sock *sock)
+{
+	return sock->sk_security + smack_blob_sizes.lbs_sock;
+}
+
 /*
  * Is the directory transmuting?
  */
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 223a6da0e6dc..1ee0bf1493f6 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1429,7 +1429,7 @@ static int smack_inode_getsecurity(struct user_namespace *mnt_userns,
 		if (sock == NULL || sock->sk == NULL)
 			return -EOPNOTSUPP;
 
-		ssp = sock->sk->sk_security;
+		ssp = smack_sock(sock->sk);
 
 		if (strcmp(name, XATTR_SMACK_IPIN) == 0)
 			isp = ssp->smk_in;
@@ -1811,7 +1811,7 @@ static int smack_file_receive(struct file *file)
 
 	if (inode->i_sb->s_magic == SOCKFS_MAGIC) {
 		sock = SOCKET_I(inode);
-		ssp = sock->sk->sk_security;
+		ssp = smack_sock(sock->sk);
 		tsp = smack_cred(current_cred());
 		/*
 		 * If the receiving process can't write to the
@@ -2232,11 +2232,7 @@ static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
 static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
 {
 	struct smack_known *skp = smk_of_current();
-	struct socket_smack *ssp;
-
-	ssp = kzalloc(sizeof(struct socket_smack), gfp_flags);
-	if (ssp == NULL)
-		return -ENOMEM;
+	struct socket_smack *ssp = smack_sock(sk);
 
 	/*
 	 * Sockets created by kernel threads receive web label.
@@ -2250,11 +2246,10 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
 	}
 	ssp->smk_packet = NULL;
 
-	sk->sk_security = ssp;
-
 	return 0;
 }
 
+#ifdef SMACK_IPV6_PORT_LABELING
 /**
  * smack_sk_free_security - Free a socket blob
  * @sk: the socket
@@ -2263,7 +2258,6 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
  */
 static void smack_sk_free_security(struct sock *sk)
 {
-#ifdef SMACK_IPV6_PORT_LABELING
 	struct smk_port_label *spp;
 
 	if (sk->sk_family == PF_INET6) {
@@ -2276,9 +2270,8 @@ static void smack_sk_free_security(struct sock *sk)
 		}
 		rcu_read_unlock();
 	}
-#endif
-	kfree(sk->sk_security);
 }
+#endif
 
 /**
 * smack_ipv4host_label - check host based restrictions
@@ -2391,7 +2384,7 @@ static struct smack_known *smack_ipv6host_label(struct sockaddr_in6 *sip)
  */
 static int smack_netlbl_add(struct sock *sk)
 {
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sk);
 	struct smack_known *skp = ssp->smk_out;
 	int rc;
 
@@ -2423,7 +2416,7 @@ static int smack_netlbl_add(struct sock *sk)
  */
 static void smack_netlbl_delete(struct sock *sk)
 {
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sk);
 
 	/*
 	 * Take the label off the socket if one is set.
@@ -2455,7 +2448,7 @@ static int smk_ipv4_check(struct sock *sk, struct sockaddr_in *sap)
 	struct smack_known *skp;
 	int rc = 0;
 	struct smack_known *hkp;
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sk);
 	struct smk_audit_info ad;
 
 	rcu_read_lock();
@@ -2528,7 +2521,7 @@ static void smk_ipv6_port_label(struct socket *sock, struct sockaddr *address)
 {
 	struct sock *sk = sock->sk;
 	struct sockaddr_in6 *addr6;
-	struct socket_smack *ssp = sock->sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sock->sk);
 	struct smk_port_label *spp;
 	unsigned short port = 0;
 
@@ -2617,7 +2610,7 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
 				int act)
 {
 	struct smk_port_label *spp;
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sk);
 	struct smack_known *skp = NULL;
 	unsigned short port;
 	struct smack_known *object;
@@ -2710,7 +2703,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
 	if (sock == NULL || sock->sk == NULL)
 		return -EOPNOTSUPP;
 
-	ssp = sock->sk->sk_security;
+	ssp = smack_sock(sock->sk);
 
 	if (strcmp(name, XATTR_SMACK_IPIN) == 0)
 		ssp->smk_in = skp;
@@ -2758,7 +2751,7 @@ static int smack_socket_post_create(struct socket *sock, int family,
 	 * Sockets created by kernel threads receive web label.
 	 */
 	if (unlikely(current->flags & PF_KTHREAD)) {
-		ssp = sock->sk->sk_security;
+		ssp = smack_sock(sock->sk);
 		ssp->smk_in = &smack_known_web;
 		ssp->smk_out = &smack_known_web;
 	}
@@ -2783,8 +2776,8 @@ static int smack_socket_post_create(struct socket *sock, int family,
 static int smack_socket_socketpair(struct socket *socka,
 		                   struct socket *sockb)
 {
-	struct socket_smack *asp = socka->sk->sk_security;
-	struct socket_smack *bsp = sockb->sk->sk_security;
+	struct socket_smack *asp = smack_sock(socka->sk);
+	struct socket_smack *bsp = smack_sock(sockb->sk);
 
 	asp->smk_packet = bsp->smk_out;
 	bsp->smk_packet = asp->smk_out;
@@ -2847,7 +2840,7 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
 		if (__is_defined(SMACK_IPV6_SECMARK_LABELING))
 			rsp = smack_ipv6host_label(sip);
 		if (rsp != NULL) {
-			struct socket_smack *ssp = sock->sk->sk_security;
+			struct socket_smack *ssp = smack_sock(sock->sk);
 
 			rc = smk_ipv6_check(ssp->smk_out, rsp, sip,
 					    SMK_CONNECTING);
@@ -3575,9 +3568,9 @@ static int smack_unix_stream_connect(struct sock *sock,
 {
 	struct smack_known *skp;
 	struct smack_known *okp;
-	struct socket_smack *ssp = sock->sk_security;
-	struct socket_smack *osp = other->sk_security;
-	struct socket_smack *nsp = newsk->sk_security;
+	struct socket_smack *ssp = smack_sock(sock);
+	struct socket_smack *osp = smack_sock(other);
+	struct socket_smack *nsp = smack_sock(newsk);
 	struct smk_audit_info ad;
 	int rc = 0;
 #ifdef CONFIG_AUDIT
@@ -3623,8 +3616,8 @@ static int smack_unix_stream_connect(struct sock *sock,
  */
 static int smack_unix_may_send(struct socket *sock, struct socket *other)
 {
-	struct socket_smack *ssp = sock->sk->sk_security;
-	struct socket_smack *osp = other->sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sock->sk);
+	struct socket_smack *osp = smack_sock(other->sk);
 	struct smk_audit_info ad;
 	int rc;
 
@@ -3661,7 +3654,7 @@ static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg,
 	struct sockaddr_in6 *sap = (struct sockaddr_in6 *) msg->msg_name;
 #endif
 #ifdef SMACK_IPV6_SECMARK_LABELING
-	struct socket_smack *ssp = sock->sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sock->sk);
 	struct smack_known *rsp;
 #endif
 	int rc = 0;
@@ -3873,7 +3866,7 @@ static struct smack_known *smack_from_netlbl(const struct sock *sk, u16 family,
 	netlbl_secattr_init(&secattr);
 
 	if (sk)
-		ssp = sk->sk_security;
+		ssp = smack_sock(sk);
 
 	if (netlbl_skbuff_getattr(skb, family, &secattr) == 0) {
 		skp = smack_from_secattr(&secattr, ssp);
@@ -3895,7 +3888,7 @@ static struct smack_known *smack_from_netlbl(const struct sock *sk, u16 family,
  */
 static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 {
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sk);
 	struct smack_known *skp = NULL;
 	int rc = 0;
 	struct smk_audit_info ad;
@@ -3999,7 +3992,7 @@ static int smack_socket_getpeersec_stream(struct socket *sock,
 	int slen = 1;
 	int rc = 0;
 
-	ssp = sock->sk->sk_security;
+	ssp = smack_sock(sock->sk);
 	if (ssp->smk_packet != NULL) {
 		rcp = ssp->smk_packet->smk_known;
 		slen = strlen(rcp) + 1;
@@ -4048,7 +4041,7 @@ static int smack_socket_getpeersec_dgram(struct socket *sock,
 
 	switch (family) {
 	case PF_UNIX:
-		ssp = sock->sk->sk_security;
+		ssp = smack_sock(sock->sk);
 		s = ssp->smk_out->smk_secid;
 		break;
 	case PF_INET:
@@ -4097,7 +4090,7 @@ static void smack_sock_graft(struct sock *sk, struct socket *parent)
 	    (sk->sk_family != PF_INET && sk->sk_family != PF_INET6))
 		return;
 
-	ssp = sk->sk_security;
+	ssp = smack_sock(sk);
 	ssp->smk_in = skp;
 	ssp->smk_out = skp;
 	/* cssp->smk_packet is already set in smack_inet_csk_clone() */
@@ -4117,7 +4110,7 @@ static int smack_inet_conn_request(const struct sock *sk, struct sk_buff *skb,
 {
 	u16 family = sk->sk_family;
 	struct smack_known *skp;
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sk);
 	struct sockaddr_in addr;
 	struct iphdr *hdr;
 	struct smack_known *hskp;
@@ -4203,7 +4196,7 @@ static int smack_inet_conn_request(const struct sock *sk, struct sk_buff *skb,
 static void smack_inet_csk_clone(struct sock *sk,
 				 const struct request_sock *req)
 {
-	struct socket_smack *ssp = sk->sk_security;
+	struct socket_smack *ssp = smack_sock(sk);
 	struct smack_known *skp;
 
 	if (req->peer_secid != 0) {
@@ -4697,6 +4690,7 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
 	.lbs_inode = sizeof(struct inode_smack),
 	.lbs_ipc = sizeof(struct smack_known *),
 	.lbs_msg_msg = sizeof(struct smack_known *),
+	.lbs_sock = sizeof(struct socket_smack),
 	.lbs_superblock = sizeof(struct superblock_smack),
 };
 
@@ -4807,7 +4801,9 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(socket_getpeersec_stream, smack_socket_getpeersec_stream),
 	LSM_HOOK_INIT(socket_getpeersec_dgram, smack_socket_getpeersec_dgram),
 	LSM_HOOK_INIT(sk_alloc_security, smack_sk_alloc_security),
+#ifdef SMACK_IPV6_PORT_LABELING
 	LSM_HOOK_INIT(sk_free_security, smack_sk_free_security),
+#endif
 	LSM_HOOK_INIT(sock_graft, smack_sock_graft),
 	LSM_HOOK_INIT(inet_conn_request, smack_inet_conn_request),
 	LSM_HOOK_INIT(inet_csk_clone, smack_inet_csk_clone),
diff --git a/security/smack/smack_netfilter.c b/security/smack/smack_netfilter.c
index fc7399b45373..635e2339579e 100644
--- a/security/smack/smack_netfilter.c
+++ b/security/smack/smack_netfilter.c
@@ -28,8 +28,8 @@ static unsigned int smack_ipv6_output(void *priv,
 	struct socket_smack *ssp;
 	struct smack_known *skp;
 
-	if (sk && sk->sk_security) {
-		ssp = sk->sk_security;
+	if (sk && smack_sock(sk)) {
+		ssp = smack_sock(sk);
 		skp = ssp->smk_out;
 		skb->secmark = skp->smk_secid;
 	}
@@ -46,8 +46,8 @@ static unsigned int smack_ipv4_output(void *priv,
 	struct socket_smack *ssp;
 	struct smack_known *skp;
 
-	if (sk && sk->sk_security) {
-		ssp = sk->sk_security;
+	if (sk && smack_sock(sk)) {
+		ssp = smack_sock(sk);
 		skp = ssp->smk_out;
 		skb->secmark = skp->smk_secid;
 	}
-- 
2.29.2

[PATCH v26 02/25] LSM: Add the lsmblob data structure.

[Casey Schaufler]

When more than one security module is exporting data to
audit and networking sub-systems a single 32 bit integer
is no longer sufficient to represent the data. Add a
structure to be used instead.

The lsmblob structure is currently an array of
u32 "secids". There is an entry for each of the
security modules built into the system that would
use secids if active. The system assigns the module
a "slot" when it registers hooks. If modules are
compiled in but not registered there will be unused
slots.

A new lsm_id structure, which contains the name
of the LSM and its slot number, is created. There
is an instance for each LSM, which assigns the name
and passes it to the infrastructure to set the slot.

The audit rules data is expanded to use an array of
security module data rather than a single instance.
Because IMA uses the audit rule functions it is
affected as well.

Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: <bpf@vger.kernel.org>
Cc: linux-audit@redhat.com
Cc: linux-security-module@vger.kernel.org
Cc: selinux@vger.kernel.org
To: Mimi Zohar <zohar@linux.ibm.com>
To: Mickaël Salaün <mic@linux.microsoft.com>
---
 include/linux/audit.h               |  4 +-
 include/linux/lsm_hooks.h           | 12 ++++-
 include/linux/security.h            | 67 +++++++++++++++++++++++++--
 kernel/auditfilter.c                | 24 +++++-----
 kernel/auditsc.c                    | 13 +++---
 security/apparmor/lsm.c             |  7 ++-
 security/bpf/hooks.c                | 12 ++++-
 security/commoncap.c                |  7 ++-
 security/integrity/ima/ima_policy.c | 40 +++++++++++-----
 security/landlock/cred.c            |  2 +-
 security/landlock/fs.c              |  2 +-
 security/landlock/ptrace.c          |  2 +-
 security/landlock/setup.c           |  4 ++
 security/landlock/setup.h           |  1 +
 security/loadpin/loadpin.c          |  8 +++-
 security/lockdown/lockdown.c        |  7 ++-
 security/safesetid/lsm.c            |  8 +++-
 security/security.c                 | 72 ++++++++++++++++++++++++-----
 security/selinux/hooks.c            |  8 +++-
 security/smack/smack_lsm.c          |  7 ++-
 security/tomoyo/tomoyo.c            |  8 +++-
 security/yama/yama_lsm.c            |  7 ++-
 22 files changed, 262 insertions(+), 60 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 82b7c1116a85..418a485af114 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -11,6 +11,7 @@
 
 #include <linux/sched.h>
 #include <linux/ptrace.h>
+#include <linux/security.h>
 #include <uapi/linux/audit.h>
 #include <uapi/linux/netfilter/nf_tables.h>
 
@@ -65,8 +66,9 @@ struct audit_field {
 		kuid_t			uid;
 		kgid_t			gid;
 		struct {
+			bool		lsm_isset;
 			char		*lsm_str;
-			void		*lsm_rule;
+			void		*lsm_rules[LSMBLOB_ENTRIES];
 		};
 	};
 	u32				op;
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index afd3b16875b0..c61a16f0a5bc 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1570,6 +1570,14 @@ struct security_hook_heads {
 	#undef LSM_HOOK
 } __randomize_layout;
 
+/*
+ * Information that identifies a security module.
+ */
+struct lsm_id {
+	const char	*lsm;	/* Name of the LSM */
+	int		slot;	/* Slot in lsmblob if one is allocated */
+};
+
 /*
  * Security module hook list structure.
  * For use with generic list macros for common operations.
@@ -1578,7 +1586,7 @@ struct security_hook_list {
 	struct hlist_node		list;
 	struct hlist_head		*head;
 	union security_list_options	hook;
-	char				*lsm;
+	struct lsm_id			*lsmid;
 } __randomize_layout;
 
 /*
@@ -1614,7 +1622,7 @@ extern struct security_hook_heads security_hook_heads;
 extern char *lsm_names;
 
 extern void security_add_hooks(struct security_hook_list *hooks, int count,
-				char *lsm);
+			       struct lsm_id *lsmid);
 
 #define LSM_FLAG_LEGACY_MAJOR	BIT(0)
 #define LSM_FLAG_EXCLUSIVE	BIT(1)
diff --git a/include/linux/security.h b/include/linux/security.h
index 06f7c50ce77f..62588bc522ba 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -133,6 +133,65 @@ enum lockdown_reason {
 
 extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1];
 
+/*
+ * Data exported by the security modules
+ *
+ * Any LSM that provides secid or secctx based hooks must be included.
+ */
+#define LSMBLOB_ENTRIES ( \
+	(IS_ENABLED(CONFIG_SECURITY_SELINUX) ? 1 : 0) + \
+	(IS_ENABLED(CONFIG_SECURITY_SMACK) ? 1 : 0) + \
+	(IS_ENABLED(CONFIG_SECURITY_APPARMOR) ? 1 : 0) + \
+	(IS_ENABLED(CONFIG_BPF_LSM) ? 1 : 0))
+
+struct lsmblob {
+	u32     secid[LSMBLOB_ENTRIES];
+};
+
+#define LSMBLOB_INVALID		-1	/* Not a valid LSM slot number */
+#define LSMBLOB_NEEDED		-2	/* Slot requested on initialization */
+#define LSMBLOB_NOT_NEEDED	-3	/* Slot not requested */
+
+/**
+ * lsmblob_init - initialize an lsmblob structure
+ * @blob: Pointer to the data to initialize
+ * @secid: The initial secid value
+ *
+ * Set all secid for all modules to the specified value.
+ */
+static inline void lsmblob_init(struct lsmblob *blob, u32 secid)
+{
+	int i;
+
+	for (i = 0; i < LSMBLOB_ENTRIES; i++)
+		blob->secid[i] = secid;
+}
+
+/**
+ * lsmblob_is_set - report if there is an value in the lsmblob
+ * @blob: Pointer to the exported LSM data
+ *
+ * Returns true if there is a secid set, false otherwise
+ */
+static inline bool lsmblob_is_set(struct lsmblob *blob)
+{
+	struct lsmblob empty = {};
+
+	return !!memcmp(blob, &empty, sizeof(*blob));
+}
+
+/**
+ * lsmblob_equal - report if the two lsmblob's are equal
+ * @bloba: Pointer to one LSM data
+ * @blobb: Pointer to the other LSM data
+ *
+ * Returns true if all entries in the two are equal, false otherwise
+ */
+static inline bool lsmblob_equal(struct lsmblob *bloba, struct lsmblob *blobb)
+{
+	return !memcmp(bloba, blobb, sizeof(*bloba));
+}
+
 /* These functions are in security/commoncap.c */
 extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
 		       int cap, unsigned int opts);
@@ -1881,8 +1940,8 @@ static inline int security_key_getsecurity(struct key *key, char **_buffer)
 #ifdef CONFIG_SECURITY
 int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule);
 int security_audit_rule_known(struct audit_krule *krule);
-int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule);
-void security_audit_rule_free(void *lsmrule);
+int security_audit_rule_match(u32 secid, u32 field, u32 op, void **lsmrule);
+void security_audit_rule_free(void **lsmrule);
 
 #else
 
@@ -1898,12 +1957,12 @@ static inline int security_audit_rule_known(struct audit_krule *krule)
 }
 
 static inline int security_audit_rule_match(u32 secid, u32 field, u32 op,
-					    void *lsmrule)
+					    void **lsmrule)
 {
 	return 0;
 }
 
-static inline void security_audit_rule_free(void *lsmrule)
+static inline void security_audit_rule_free(void **lsmrule)
 { }
 
 #endif /* CONFIG_SECURITY */
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index db2c6b59dfc3..a2340e81cfa7 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -74,7 +74,7 @@ static void audit_free_lsm_field(struct audit_field *f)
 	case AUDIT_OBJ_LEV_LOW:
 	case AUDIT_OBJ_LEV_HIGH:
 		kfree(f->lsm_str);
-		security_audit_rule_free(f->lsm_rule);
+		security_audit_rule_free(f->lsm_rules);
 	}
 }
 
@@ -519,9 +519,10 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
 				goto exit_free;
 			}
 			entry->rule.buflen += f_val;
+			f->lsm_isset = true;
 			f->lsm_str = str;
 			err = security_audit_rule_init(f->type, f->op, str,
-						       (void **)&f->lsm_rule);
+						       f->lsm_rules);
 			/* Keep currently invalid fields around in case they
 			 * become valid after a policy reload. */
 			if (err == -EINVAL) {
@@ -774,7 +775,7 @@ static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 	return 0;
 }
 
-/* Duplicate LSM field information.  The lsm_rule is opaque, so must be
+/* Duplicate LSM field information.  The lsm_rules is opaque, so must be
  * re-initialized. */
 static inline int audit_dupe_lsm_field(struct audit_field *df,
 					   struct audit_field *sf)
@@ -788,9 +789,9 @@ static inline int audit_dupe_lsm_field(struct audit_field *df,
 		return -ENOMEM;
 	df->lsm_str = lsm_str;
 
-	/* our own (refreshed) copy of lsm_rule */
+	/* our own (refreshed) copy of lsm_rules */
 	ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
-				       (void **)&df->lsm_rule);
+				       df->lsm_rules);
 	/* Keep currently invalid fields around in case they
 	 * become valid after a policy reload. */
 	if (ret == -EINVAL) {
@@ -842,7 +843,7 @@ struct audit_entry *audit_dupe_rule(struct audit_krule *old)
 	new->tree = old->tree;
 	memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
 
-	/* deep copy this information, updating the lsm_rule fields, because
+	/* deep copy this information, updating the lsm_rules fields, because
 	 * the originals will all be freed when the old rule is freed. */
 	for (i = 0; i < fcount; i++) {
 		switch (new->fields[i].type) {
@@ -1358,11 +1359,12 @@ int audit_filter(int msgtype, unsigned int listtype)
 			case AUDIT_SUBJ_TYPE:
 			case AUDIT_SUBJ_SEN:
 			case AUDIT_SUBJ_CLR:
-				if (f->lsm_rule) {
+				if (f->lsm_isset) {
 					security_task_getsecid_subj(current,
 								    &sid);
 					result = security_audit_rule_match(sid,
-						   f->type, f->op, f->lsm_rule);
+						   f->type, f->op,
+						   f->lsm_rules);
 				}
 				break;
 			case AUDIT_EXE:
@@ -1389,7 +1391,7 @@ int audit_filter(int msgtype, unsigned int listtype)
 	return ret;
 }
 
-static int update_lsm_rule(struct audit_krule *r)
+static int update_lsm_rules(struct audit_krule *r)
 {
 	struct audit_entry *entry = container_of(r, struct audit_entry, rule);
 	struct audit_entry *nentry;
@@ -1421,7 +1423,7 @@ static int update_lsm_rule(struct audit_krule *r)
 	return err;
 }
 
-/* This function will re-initialize the lsm_rule field of all applicable rules.
+/* This function will re-initialize the lsm_rules field of all applicable rules.
  * It will traverse the filter lists serarching for rules that contain LSM
  * specific filter fields.  When such a rule is found, it is copied, the
  * LSM field is re-initialized, and the old rule is replaced with the
@@ -1436,7 +1438,7 @@ int audit_update_lsm_rules(void)
 
 	for (i = 0; i < AUDIT_NR_FILTERS; i++) {
 		list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
-			int res = update_lsm_rule(r);
+			int res = update_lsm_rules(r);
 			if (!err)
 				err = res;
 		}
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 175ef6f3ea4e..392afe3e2fd6 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -665,14 +665,13 @@ static int audit_filter_rules(struct task_struct *tsk,
 			   match for now to avoid losing information that
 			   may be wanted.   An error message will also be
 			   logged upon error */
-			if (f->lsm_rule) {
+			if (f->lsm_isset) {
 				if (need_sid) {
 					security_task_getsecid_subj(tsk, &sid);
 					need_sid = 0;
 				}
 				result = security_audit_rule_match(sid, f->type,
-								   f->op,
-								   f->lsm_rule);
+							f->op, f->lsm_rules);
 			}
 			break;
 		case AUDIT_OBJ_USER:
@@ -682,21 +681,21 @@ static int audit_filter_rules(struct task_struct *tsk,
 		case AUDIT_OBJ_LEV_HIGH:
 			/* The above note for AUDIT_SUBJ_USER...AUDIT_SUBJ_CLR
 			   also applies here */
-			if (f->lsm_rule) {
+			if (f->lsm_isset) {
 				/* Find files that match */
 				if (name) {
 					result = security_audit_rule_match(
 								name->osid,
 								f->type,
 								f->op,
-								f->lsm_rule);
+								f->lsm_rules);
 				} else if (ctx) {
 					list_for_each_entry(n, &ctx->names_list, list) {
 						if (security_audit_rule_match(
 								n->osid,
 								f->type,
 								f->op,
-								f->lsm_rule)) {
+								f->lsm_rules)) {
 							++result;
 							break;
 						}
@@ -707,7 +706,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 					break;
 				if (security_audit_rule_match(ctx->ipc.osid,
 							      f->type, f->op,
-							      f->lsm_rule))
+							      f->lsm_rules))
 					++result;
 			}
 			break;
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 4113516fb62e..392e25940d1f 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -1161,6 +1161,11 @@ struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = {
 	.lbs_sock = sizeof(struct aa_sk_ctx),
 };
 
+static struct lsm_id apparmor_lsmid __lsm_ro_after_init = {
+	.lsm  = "apparmor",
+	.slot = LSMBLOB_NEEDED
+};
+
 static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
 	LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
@@ -1862,7 +1867,7 @@ static int __init apparmor_init(void)
 		goto buffers_out;
 	}
 	security_add_hooks(apparmor_hooks, ARRAY_SIZE(apparmor_hooks),
-				"apparmor");
+				&apparmor_lsmid);
 
 	/* Report that AppArmor successfully initialized */
 	apparmor_initialized = 1;
diff --git a/security/bpf/hooks.c b/security/bpf/hooks.c
index e5971fa74fd7..7a58fe9ab8c4 100644
--- a/security/bpf/hooks.c
+++ b/security/bpf/hooks.c
@@ -15,9 +15,19 @@ static struct security_hook_list bpf_lsm_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(task_free, bpf_task_storage_free),
 };
 
+/*
+ * slot has to be LSMBLOB_NEEDED because some of the hooks
+ * supplied by this module require a slot.
+ */
+struct lsm_id bpf_lsmid __lsm_ro_after_init = {
+	.lsm = "bpf",
+	.slot = LSMBLOB_NEEDED
+};
+
 static int __init bpf_lsm_init(void)
 {
-	security_add_hooks(bpf_lsm_hooks, ARRAY_SIZE(bpf_lsm_hooks), "bpf");
+	security_add_hooks(bpf_lsm_hooks, ARRAY_SIZE(bpf_lsm_hooks),
+			   &bpf_lsmid);
 	pr_info("LSM support for eBPF active\n");
 	return 0;
 }
diff --git a/security/commoncap.c b/security/commoncap.c
index 3f810d37b71b..628685cf20e3 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -1443,6 +1443,11 @@ int cap_mmap_file(struct file *file, unsigned long reqprot,
 
 #ifdef CONFIG_SECURITY
 
+static struct lsm_id capability_lsmid __lsm_ro_after_init = {
+	.lsm  = "capability",
+	.slot = LSMBLOB_NOT_NEEDED
+};
+
 static struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(capable, cap_capable),
 	LSM_HOOK_INIT(settime, cap_settime),
@@ -1467,7 +1472,7 @@ static struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
 static int __init capability_init(void)
 {
 	security_add_hooks(capability_hooks, ARRAY_SIZE(capability_hooks),
-				"capability");
+			   &capability_lsmid);
 	return 0;
 }
 
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index fd5d46e511f1..5c40677e881c 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -80,7 +80,7 @@ struct ima_rule_entry {
 	bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
 	int pcr;
 	struct {
-		void *rule;	/* LSM file metadata specific */
+		void *rules[LSMBLOB_ENTRIES]; /* LSM file metadata specific */
 		char *args_p;	/* audit value */
 		int type;	/* audit type */
 	} lsm[MAX_LSM_RULES];
@@ -90,6 +90,22 @@ struct ima_rule_entry {
 	struct ima_template_desc *template;
 };
 
+/**
+ * ima_lsm_isset - Is a rule set for any of the active security modules
+ * @rules: The set of IMA rules to check
+ *
+ * If a rule is set for any LSM return true, otherwise return false.
+ */
+static inline bool ima_lsm_isset(void *rules[])
+{
+	int i;
+
+	for (i = 0; i < LSMBLOB_ENTRIES; i++)
+		if (rules[i])
+			return true;
+	return false;
+}
+
 /*
  * Without LSM specific knowledge, the default policy can only be
  * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
@@ -335,9 +351,11 @@ static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
 static void ima_lsm_free_rule(struct ima_rule_entry *entry)
 {
 	int i;
+	int r;
 
 	for (i = 0; i < MAX_LSM_RULES; i++) {
-		ima_filter_rule_free(entry->lsm[i].rule);
+		for (r = 0; r < LSMBLOB_ENTRIES; r++)
+			ima_filter_rule_free(entry->lsm[i].rules[r]);
 		kfree(entry->lsm[i].args_p);
 	}
 }
@@ -388,8 +406,8 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
 
 		ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
 				     nentry->lsm[i].args_p,
-				     &nentry->lsm[i].rule);
-		if (!nentry->lsm[i].rule)
+				     &nentry->lsm[i].rules[0]);
+		if (!ima_lsm_isset(nentry->lsm[i].rules))
 			pr_warn("rule for LSM \'%s\' is undefined\n",
 				nentry->lsm[i].args_p);
 	}
@@ -578,7 +596,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
 		int rc = 0;
 		u32 osid;
 
-		if (!rule->lsm[i].rule) {
+		if (!ima_lsm_isset(rule->lsm[i].rules)) {
 			if (!rule->lsm[i].args_p)
 				continue;
 			else
@@ -591,14 +609,14 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
 			security_inode_getsecid(inode, &osid);
 			rc = ima_filter_rule_match(osid, rule->lsm[i].type,
 						   Audit_equal,
-						   rule->lsm[i].rule);
+						   rule->lsm[i].rules);
 			break;
 		case LSM_SUBJ_USER:
 		case LSM_SUBJ_ROLE:
 		case LSM_SUBJ_TYPE:
 			rc = ima_filter_rule_match(secid, rule->lsm[i].type,
 						   Audit_equal,
-						   rule->lsm[i].rule);
+						   rule->lsm[i].rules);
 			break;
 		default:
 			break;
@@ -994,7 +1012,7 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 {
 	int result;
 
-	if (entry->lsm[lsm_rule].rule)
+	if (ima_lsm_isset(entry->lsm[lsm_rule].rules))
 		return -EINVAL;
 
 	entry->lsm[lsm_rule].args_p = match_strdup(args);
@@ -1004,8 +1022,8 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 	entry->lsm[lsm_rule].type = audit_type;
 	result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
 				      entry->lsm[lsm_rule].args_p,
-				      &entry->lsm[lsm_rule].rule);
-	if (!entry->lsm[lsm_rule].rule) {
+				      &entry->lsm[lsm_rule].rules[0]);
+	if (!ima_lsm_isset(entry->lsm[lsm_rule].rules)) {
 		pr_warn("rule for LSM \'%s\' is undefined\n",
 			entry->lsm[lsm_rule].args_p);
 
@@ -1812,7 +1830,7 @@ int ima_policy_show(struct seq_file *m, void *v)
 	}
 
 	for (i = 0; i < MAX_LSM_RULES; i++) {
-		if (entry->lsm[i].rule) {
+		if (ima_lsm_isset(entry->lsm[i].rules)) {
 			switch (i) {
 			case LSM_OBJ_USER:
 				seq_printf(m, pt(Opt_obj_user),
diff --git a/security/landlock/cred.c b/security/landlock/cred.c
index 6725af24c684..56b121d65436 100644
--- a/security/landlock/cred.c
+++ b/security/landlock/cred.c
@@ -42,5 +42,5 @@ static struct security_hook_list landlock_hooks[] __lsm_ro_after_init = {
 __init void landlock_add_cred_hooks(void)
 {
 	security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
-			LANDLOCK_NAME);
+			&landlock_lsmid);
 }
diff --git a/security/landlock/fs.c b/security/landlock/fs.c
index 97b8e421f617..319e90e9290c 100644
--- a/security/landlock/fs.c
+++ b/security/landlock/fs.c
@@ -688,5 +688,5 @@ static struct security_hook_list landlock_hooks[] __lsm_ro_after_init = {
 __init void landlock_add_fs_hooks(void)
 {
 	security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
-			LANDLOCK_NAME);
+			&landlock_lsmid);
 }
diff --git a/security/landlock/ptrace.c b/security/landlock/ptrace.c
index f55b82446de2..54ccf55a077a 100644
--- a/security/landlock/ptrace.c
+++ b/security/landlock/ptrace.c
@@ -116,5 +116,5 @@ static struct security_hook_list landlock_hooks[] __lsm_ro_after_init = {
 __init void landlock_add_ptrace_hooks(void)
 {
 	security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
-			LANDLOCK_NAME);
+			&landlock_lsmid);
 }
diff --git a/security/landlock/setup.c b/security/landlock/setup.c
index f8e8e980454c..4a12666a4090 100644
--- a/security/landlock/setup.c
+++ b/security/landlock/setup.c
@@ -23,6 +23,10 @@ struct lsm_blob_sizes landlock_blob_sizes __lsm_ro_after_init = {
 	.lbs_superblock = sizeof(struct landlock_superblock_security),
 };
 
+struct lsm_id landlock_lsmid __lsm_ro_after_init = {
+	.lsm = LANDLOCK_NAME,
+};
+
 static int __init landlock_init(void)
 {
 	landlock_add_cred_hooks();
diff --git a/security/landlock/setup.h b/security/landlock/setup.h
index 1daffab1ab4b..38bce5b172dc 100644
--- a/security/landlock/setup.h
+++ b/security/landlock/setup.h
@@ -14,5 +14,6 @@
 extern bool landlock_initialized;
 
 extern struct lsm_blob_sizes landlock_blob_sizes;
+extern struct lsm_id landlock_lsmid;
 
 #endif /* _SECURITY_LANDLOCK_SETUP_H */
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index b12f7d986b1e..b569f3bc170b 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -192,6 +192,11 @@ static int loadpin_load_data(enum kernel_load_data_id id, bool contents)
 	return loadpin_read_file(NULL, (enum kernel_read_file_id) id, contents);
 }
 
+static struct lsm_id loadpin_lsmid __lsm_ro_after_init = {
+	.lsm  = "loadpin",
+	.slot = LSMBLOB_NOT_NEEDED
+};
+
 static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(sb_free_security, loadpin_sb_free_security),
 	LSM_HOOK_INIT(kernel_read_file, loadpin_read_file),
@@ -239,7 +244,8 @@ static int __init loadpin_init(void)
 	pr_info("ready to pin (currently %senforcing)\n",
 		enforce ? "" : "not ");
 	parse_exclude();
-	security_add_hooks(loadpin_hooks, ARRAY_SIZE(loadpin_hooks), "loadpin");
+	security_add_hooks(loadpin_hooks, ARRAY_SIZE(loadpin_hooks),
+			   &loadpin_lsmid);
 	return 0;
 }
 
diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
index 87cbdc64d272..4e24ea3f7b7e 100644
--- a/security/lockdown/lockdown.c
+++ b/security/lockdown/lockdown.c
@@ -75,6 +75,11 @@ static struct security_hook_list lockdown_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(locked_down, lockdown_is_locked_down),
 };
 
+static struct lsm_id lockdown_lsmid __lsm_ro_after_init = {
+	.lsm = "lockdown",
+	.slot = LSMBLOB_NOT_NEEDED
+};
+
 static int __init lockdown_lsm_init(void)
 {
 #if defined(CONFIG_LOCK_DOWN_KERNEL_FORCE_INTEGRITY)
@@ -83,7 +88,7 @@ static int __init lockdown_lsm_init(void)
 	lock_kernel_down("Kernel configuration", LOCKDOWN_CONFIDENTIALITY_MAX);
 #endif
 	security_add_hooks(lockdown_hooks, ARRAY_SIZE(lockdown_hooks),
-			   "lockdown");
+			   &lockdown_lsmid);
 	return 0;
 }
 
diff --git a/security/safesetid/lsm.c b/security/safesetid/lsm.c
index 1079c6d54784..a2a2f462a821 100644
--- a/security/safesetid/lsm.c
+++ b/security/safesetid/lsm.c
@@ -241,6 +241,11 @@ static int safesetid_task_fix_setgid(struct cred *new,
 	return -EACCES;
 }
 
+static struct lsm_id safesetid_lsmid __lsm_ro_after_init = {
+	.lsm  = "safesetid",
+	.slot = LSMBLOB_NOT_NEEDED
+};
+
 static struct security_hook_list safesetid_security_hooks[] = {
 	LSM_HOOK_INIT(task_fix_setuid, safesetid_task_fix_setuid),
 	LSM_HOOK_INIT(task_fix_setgid, safesetid_task_fix_setgid),
@@ -250,7 +255,8 @@ static struct security_hook_list safesetid_security_hooks[] = {
 static int __init safesetid_security_init(void)
 {
 	security_add_hooks(safesetid_security_hooks,
-			   ARRAY_SIZE(safesetid_security_hooks), "safesetid");
+			   ARRAY_SIZE(safesetid_security_hooks),
+			   &safesetid_lsmid);
 
 	/* Report that SafeSetID successfully initialized */
 	safesetid_initialized = 1;
diff --git a/security/security.c b/security/security.c
index e12a7c463468..a3276deb1b8a 100644
--- a/security/security.c
+++ b/security/security.c
@@ -344,6 +344,7 @@ static void __init ordered_lsm_init(void)
 	init_debug("sock blob size       = %d\n", blob_sizes.lbs_sock);
 	init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock);
 	init_debug("task blob size       = %d\n", blob_sizes.lbs_task);
+	init_debug("lsmblob size         = %zu\n", sizeof(struct lsmblob));
 
 	/*
 	 * Create any kmem_caches needed for blobs
@@ -471,21 +472,36 @@ static int lsm_append(const char *new, char **result)
 	return 0;
 }
 
+/*
+ * Current index to use while initializing the lsmblob secid list.
+ */
+static int lsm_slot __lsm_ro_after_init;
+
 /**
  * security_add_hooks - Add a modules hooks to the hook lists.
  * @hooks: the hooks to add
  * @count: the number of hooks to add
- * @lsm: the name of the security module
+ * @lsmid: the identification information for the security module
  *
  * Each LSM has to register its hooks with the infrastructure.
+ * If the LSM is using hooks that export secids allocate a slot
+ * for it in the lsmblob.
  */
 void __init security_add_hooks(struct security_hook_list *hooks, int count,
-				char *lsm)
+			       struct lsm_id *lsmid)
 {
 	int i;
 
+	if (lsmid->slot == LSMBLOB_NEEDED) {
+		if (lsm_slot >= LSMBLOB_ENTRIES)
+			panic("%s Too many LSMs registered.\n", __func__);
+		lsmid->slot = lsm_slot++;
+		init_debug("%s assigned lsmblob slot %d\n", lsmid->lsm,
+			   lsmid->slot);
+	}
+
 	for (i = 0; i < count; i++) {
-		hooks[i].lsm = lsm;
+		hooks[i].lsmid = lsmid;
 		hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
 	}
 
@@ -494,7 +510,7 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
 	 * and fix this up afterwards.
 	 */
 	if (slab_is_available()) {
-		if (lsm_append(lsm, &lsm_names) < 0)
+		if (lsm_append(lsmid->lsm, &lsm_names) < 0)
 			panic("%s - Cannot get early memory.\n", __func__);
 	}
 }
@@ -2070,7 +2086,7 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
 	struct security_hook_list *hp;
 
 	hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
-		if (lsm != NULL && strcmp(lsm, hp->lsm))
+		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
 			continue;
 		return hp->hook.getprocattr(p, name, value);
 	}
@@ -2083,7 +2099,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 	struct security_hook_list *hp;
 
 	hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) {
-		if (lsm != NULL && strcmp(lsm, hp->lsm))
+		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
 			continue;
 		return hp->hook.setprocattr(name, value, size);
 	}
@@ -2576,7 +2592,24 @@ int security_key_getsecurity(struct key *key, char **_buffer)
 
 int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule)
 {
-	return call_int_hook(audit_rule_init, 0, field, op, rulestr, lsmrule);
+	struct security_hook_list *hp;
+	bool one_is_good = false;
+	int rc = 0;
+	int trc;
+
+	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_init, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		trc = hp->hook.audit_rule_init(field, op, rulestr,
+					       &lsmrule[hp->lsmid->slot]);
+		if (trc == 0)
+			one_is_good = true;
+		else
+			rc = trc;
+	}
+	if (one_is_good)
+		return 0;
+	return rc;
 }
 
 int security_audit_rule_known(struct audit_krule *krule)
@@ -2584,14 +2617,31 @@ int security_audit_rule_known(struct audit_krule *krule)
 	return call_int_hook(audit_rule_known, 0, krule);
 }
 
-void security_audit_rule_free(void *lsmrule)
+void security_audit_rule_free(void **lsmrule)
 {
-	call_void_hook(audit_rule_free, lsmrule);
+	struct security_hook_list *hp;
+
+	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_free, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		hp->hook.audit_rule_free(lsmrule[hp->lsmid->slot]);
+	}
 }
 
-int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule)
+int security_audit_rule_match(u32 secid, u32 field, u32 op, void **lsmrule)
 {
-	return call_int_hook(audit_rule_match, 0, secid, field, op, lsmrule);
+	struct security_hook_list *hp;
+	int rc;
+
+	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_match, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		rc = hp->hook.audit_rule_match(secid, field, op,
+					       &lsmrule[hp->lsmid->slot]);
+		if (rc)
+			return rc;
+	}
+	return 0;
 }
 #endif /* CONFIG_AUDIT */
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 84ddcec6322e..0133b142e938 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -7111,6 +7111,11 @@ static int selinux_perf_event_write(struct perf_event *event)
 }
 #endif
 
+static struct lsm_id selinux_lsmid __lsm_ro_after_init = {
+	.lsm  = "selinux",
+	.slot = LSMBLOB_NEEDED
+};
+
 /*
  * IMPORTANT NOTE: When adding new hooks, please be careful to keep this order:
  * 1. any hooks that don't belong to (2.) or (3.) below,
@@ -7424,7 +7429,8 @@ static __init int selinux_init(void)
 
 	hashtab_cache_init();
 
-	security_add_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks), "selinux");
+	security_add_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks),
+			   &selinux_lsmid);
 
 	if (avc_add_callback(selinux_netcache_avc_callback, AVC_CALLBACK_RESET))
 		panic("SELinux: Unable to register AVC netcache callback\n");
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 1ee0bf1493f6..5c10ad27be37 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -4694,6 +4694,11 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
 	.lbs_superblock = sizeof(struct superblock_smack),
 };
 
+static struct lsm_id smack_lsmid __lsm_ro_after_init = {
+	.lsm  = "smack",
+	.slot = LSMBLOB_NEEDED
+};
+
 static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(ptrace_access_check, smack_ptrace_access_check),
 	LSM_HOOK_INIT(ptrace_traceme, smack_ptrace_traceme),
@@ -4893,7 +4898,7 @@ static __init int smack_init(void)
 	/*
 	 * Register with LSM
 	 */
-	security_add_hooks(smack_hooks, ARRAY_SIZE(smack_hooks), "smack");
+	security_add_hooks(smack_hooks, ARRAY_SIZE(smack_hooks), &smack_lsmid);
 	smack_enabled = 1;
 
 	pr_info("Smack:  Initializing.\n");
diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c
index 1f3cd432d830..22f62c67f2ec 100644
--- a/security/tomoyo/tomoyo.c
+++ b/security/tomoyo/tomoyo.c
@@ -523,6 +523,11 @@ static void tomoyo_task_free(struct task_struct *task)
 	}
 }
 
+static struct lsm_id tomoyo_lsmid __lsm_ro_after_init = {
+	.lsm  = "tomoyo",
+	.slot = LSMBLOB_NOT_NEEDED
+};
+
 /*
  * tomoyo_security_ops is a "struct security_operations" which is used for
  * registering TOMOYO.
@@ -575,7 +580,8 @@ static int __init tomoyo_init(void)
 	struct tomoyo_task *s = tomoyo_task(current);
 
 	/* register ourselves with the security framework */
-	security_add_hooks(tomoyo_hooks, ARRAY_SIZE(tomoyo_hooks), "tomoyo");
+	security_add_hooks(tomoyo_hooks, ARRAY_SIZE(tomoyo_hooks),
+			   &tomoyo_lsmid);
 	pr_info("TOMOYO Linux initialized\n");
 	s->domain_info = &tomoyo_kernel_domain;
 	atomic_inc(&tomoyo_kernel_domain.users);
diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
index 06e226166aab..a9639ea541f7 100644
--- a/security/yama/yama_lsm.c
+++ b/security/yama/yama_lsm.c
@@ -421,6 +421,11 @@ static int yama_ptrace_traceme(struct task_struct *parent)
 	return rc;
 }
 
+static struct lsm_id yama_lsmid __lsm_ro_after_init = {
+	.lsm  = "yama",
+	.slot = LSMBLOB_NOT_NEEDED
+};
+
 static struct security_hook_list yama_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(ptrace_access_check, yama_ptrace_access_check),
 	LSM_HOOK_INIT(ptrace_traceme, yama_ptrace_traceme),
@@ -477,7 +482,7 @@ static inline void yama_init_sysctl(void) { }
 static int __init yama_init(void)
 {
 	pr_info("Yama: becoming mindful.\n");
-	security_add_hooks(yama_hooks, ARRAY_SIZE(yama_hooks), "yama");
+	security_add_hooks(yama_hooks, ARRAY_SIZE(yama_hooks), &yama_lsmid);
 	yama_init_sysctl();
 	return 0;
 }
-- 
2.29.2

Re: [PATCH v26 02/25] LSM: Add the lsmblob data structure.

[Mickaël Salaün]

I like this design but there is an issue with Landlock though, see below.

On 13/05/2021 22:07, Casey Schaufler wrote:
> When more than one security module is exporting data to
> audit and networking sub-systems a single 32 bit integer
> is no longer sufficient to represent the data. Add a
> structure to be used instead.
> 
> The lsmblob structure is currently an array of
> u32 "secids". There is an entry for each of the
> security modules built into the system that would
> use secids if active. The system assigns the module
> a "slot" when it registers hooks. If modules are
> compiled in but not registered there will be unused
> slots.
> 
> A new lsm_id structure, which contains the name
> of the LSM and its slot number, is created. There
> is an instance for each LSM, which assigns the name
> and passes it to the infrastructure to set the slot.
> 
> The audit rules data is expanded to use an array of
> security module data rather than a single instance.
> Because IMA uses the audit rule functions it is
> affected as well.
> 
> Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
> Acked-by: Paul Moore <paul@paul-moore.com>
> Acked-by: John Johansen <john.johansen@canonical.com>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> Cc: <bpf@vger.kernel.org>
> Cc: linux-audit@redhat.com
> Cc: linux-security-module@vger.kernel.org
> Cc: selinux@vger.kernel.org
> To: Mimi Zohar <zohar@linux.ibm.com>
> To: Mickaël Salaün <mic@linux.microsoft.com>
> ---
>  include/linux/audit.h               |  4 +-
>  include/linux/lsm_hooks.h           | 12 ++++-
>  include/linux/security.h            | 67 +++++++++++++++++++++++++--
>  kernel/auditfilter.c                | 24 +++++-----
>  kernel/auditsc.c                    | 13 +++---
>  security/apparmor/lsm.c             |  7 ++-
>  security/bpf/hooks.c                | 12 ++++-
>  security/commoncap.c                |  7 ++-
>  security/integrity/ima/ima_policy.c | 40 +++++++++++-----
>  security/landlock/cred.c            |  2 +-
>  security/landlock/fs.c              |  2 +-
>  security/landlock/ptrace.c          |  2 +-
>  security/landlock/setup.c           |  4 ++
>  security/landlock/setup.h           |  1 +
>  security/loadpin/loadpin.c          |  8 +++-
>  security/lockdown/lockdown.c        |  7 ++-
>  security/safesetid/lsm.c            |  8 +++-
>  security/security.c                 | 72 ++++++++++++++++++++++++-----
>  security/selinux/hooks.c            |  8 +++-
>  security/smack/smack_lsm.c          |  7 ++-
>  security/tomoyo/tomoyo.c            |  8 +++-
>  security/yama/yama_lsm.c            |  7 ++-
>  22 files changed, 262 insertions(+), 60 deletions(-)
> 

[...]

> diff --git a/security/landlock/setup.c b/security/landlock/setup.c
> index f8e8e980454c..4a12666a4090 100644
> --- a/security/landlock/setup.c
> +++ b/security/landlock/setup.c
> @@ -23,6 +23,10 @@ struct lsm_blob_sizes landlock_blob_sizes __lsm_ro_after_init = {
>  	.lbs_superblock = sizeof(struct landlock_superblock_security),
>  };
>  
> +struct lsm_id landlock_lsmid __lsm_ro_after_init = {
> +	.lsm = LANDLOCK_NAME,

It is missing: .slot = LSMBLOB_NEEDED,

You can run the Landlock tests please?
make -C tools/testing/selftests TARGETS=landlock gen_tar
tar -xf kselftest.tar.gz && ./run_kselftest.sh


> +};
> +
>  static int __init landlock_init(void)
>  {
>  	landlock_add_cred_hooks();

[...]

> diff --git a/security/security.c b/security/security.c
> index e12a7c463468..a3276deb1b8a 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -344,6 +344,7 @@ static void __init ordered_lsm_init(void)
>  	init_debug("sock blob size       = %d\n", blob_sizes.lbs_sock);
>  	init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock);
>  	init_debug("task blob size       = %d\n", blob_sizes.lbs_task);
> +	init_debug("lsmblob size         = %zu\n", sizeof(struct lsmblob));
>  
>  	/*
>  	 * Create any kmem_caches needed for blobs
> @@ -471,21 +472,36 @@ static int lsm_append(const char *new, char **result)
>  	return 0;
>  }
>  
> +/*
> + * Current index to use while initializing the lsmblob secid list.
> + */
> +static int lsm_slot __lsm_ro_after_init;
> +
>  /**
>   * security_add_hooks - Add a modules hooks to the hook lists.
>   * @hooks: the hooks to add
>   * @count: the number of hooks to add
> - * @lsm: the name of the security module
> + * @lsmid: the identification information for the security module
>   *
>   * Each LSM has to register its hooks with the infrastructure.
> + * If the LSM is using hooks that export secids allocate a slot
> + * for it in the lsmblob.
>   */
>  void __init security_add_hooks(struct security_hook_list *hooks, int count,
> -				char *lsm)
> +			       struct lsm_id *lsmid)
>  {
>  	int i;
>  

Could you add a WARN_ON(!lsmid->slot || !lsmid->name) here?


> +	if (lsmid->slot == LSMBLOB_NEEDED) {
> +		if (lsm_slot >= LSMBLOB_ENTRIES)
> +			panic("%s Too many LSMs registered.\n", __func__);
> +		lsmid->slot = lsm_slot++;
> +		init_debug("%s assigned lsmblob slot %d\n", lsmid->lsm,
> +			   lsmid->slot);
> +	}
> +
>  	for (i = 0; i < count; i++) {
> -		hooks[i].lsm = lsm;
> +		hooks[i].lsmid = lsmid;
>  		hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
>  	}
>  

Re: [PATCH v26 02/25] LSM: Add the lsmblob data structure.

[Casey Schaufler]

On 5/22/2021 1:39 AM, Mickaël Salaün wrote:
> I like this design but there is an issue with Landlock though, see below.
>
> On 13/05/2021 22:07, Casey Schaufler wrote:
>> When more than one security module is exporting data to
>> audit and networking sub-systems a single 32 bit integer
>> is no longer sufficient to represent the data. Add a
>> structure to be used instead.
>>
>> The lsmblob structure is currently an array of
>> u32 "secids". There is an entry for each of the
>> security modules built into the system that would
>> use secids if active. The system assigns the module
>> a "slot" when it registers hooks. If modules are
>> compiled in but not registered there will be unused
>> slots.
>>
>> A new lsm_id structure, which contains the name
>> of the LSM and its slot number, is created. There
>> is an instance for each LSM, which assigns the name
>> and passes it to the infrastructure to set the slot.
>>
>> The audit rules data is expanded to use an array of
>> security module data rather than a single instance.
>> Because IMA uses the audit rule functions it is
>> affected as well.
>>
>> Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
>> Acked-by: Paul Moore <paul@paul-moore.com>
>> Acked-by: John Johansen <john.johansen@canonical.com>
>> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
>> Cc: <bpf@vger.kernel.org>
>> Cc: linux-audit@redhat.com
>> Cc: linux-security-module@vger.kernel.org
>> Cc: selinux@vger.kernel.org
>> To: Mimi Zohar <zohar@linux.ibm.com>
>> To: Mickaël Salaün <mic@linux.microsoft.com>
>> ---
>>  include/linux/audit.h               |  4 +-
>>  include/linux/lsm_hooks.h           | 12 ++++-
>>  include/linux/security.h            | 67 +++++++++++++++++++++++++--
>>  kernel/auditfilter.c                | 24 +++++-----
>>  kernel/auditsc.c                    | 13 +++---
>>  security/apparmor/lsm.c             |  7 ++-
>>  security/bpf/hooks.c                | 12 ++++-
>>  security/commoncap.c                |  7 ++-
>>  security/integrity/ima/ima_policy.c | 40 +++++++++++-----
>>  security/landlock/cred.c            |  2 +-
>>  security/landlock/fs.c              |  2 +-
>>  security/landlock/ptrace.c          |  2 +-
>>  security/landlock/setup.c           |  4 ++
>>  security/landlock/setup.h           |  1 +
>>  security/loadpin/loadpin.c          |  8 +++-
>>  security/lockdown/lockdown.c        |  7 ++-
>>  security/safesetid/lsm.c            |  8 +++-
>>  security/security.c                 | 72 ++++++++++++++++++++++++-----
>>  security/selinux/hooks.c            |  8 +++-
>>  security/smack/smack_lsm.c          |  7 ++-
>>  security/tomoyo/tomoyo.c            |  8 +++-
>>  security/yama/yama_lsm.c            |  7 ++-
>>  22 files changed, 262 insertions(+), 60 deletions(-)
>>
> [...]
>
>> diff --git a/security/landlock/setup.c b/security/landlock/setup.c
>> index f8e8e980454c..4a12666a4090 100644
>> --- a/security/landlock/setup.c
>> +++ b/security/landlock/setup.c
>> @@ -23,6 +23,10 @@ struct lsm_blob_sizes landlock_blob_sizes __lsm_ro_after_init = {
>>  	.lbs_superblock = sizeof(struct landlock_superblock_security),
>>  };
>>  
>> +struct lsm_id landlock_lsmid __lsm_ro_after_init = {
>> +	.lsm = LANDLOCK_NAME,
> It is missing: .slot = LSMBLOB_NEEDED,

Sorry for the delay.

Landlock does not provide any of the hooks that use a struct lsmblob.
That would be secid_to_secctx, secctx_to_secid, inode_getsecid,
cred_getsecid, kernel_act_as task_getsecid_subj task_getsecid_obj and
ipc_getsecid. Setting .slot = LSMBLOB_NEEDED indicates that the LSM
uses a slot in struct lsmblob. Landlock does not need a slot.

>
> You can run the Landlock tests please?
> make -C tools/testing/selftests TARGETS=landlock gen_tar
> tar -xf kselftest.tar.gz && ./run_kselftest.sh

Sure. I'll add them to my routine.

>
>
>> +};
>> +
>>  static int __init landlock_init(void)
>>  {
>>  	landlock_add_cred_hooks();
> [...]
>
>> diff --git a/security/security.c b/security/security.c
>> index e12a7c463468..a3276deb1b8a 100644
>> --- a/security/security.c
>> +++ b/security/security.c
>> @@ -344,6 +344,7 @@ static void __init ordered_lsm_init(void)
>>  	init_debug("sock blob size       = %d\n", blob_sizes.lbs_sock);
>>  	init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock);
>>  	init_debug("task blob size       = %d\n", blob_sizes.lbs_task);
>> +	init_debug("lsmblob size         = %zu\n", sizeof(struct lsmblob));
>>  
>>  	/*
>>  	 * Create any kmem_caches needed for blobs
>> @@ -471,21 +472,36 @@ static int lsm_append(const char *new, char **result)
>>  	return 0;
>>  }
>>  
>> +/*
>> + * Current index to use while initializing the lsmblob secid list.
>> + */
>> +static int lsm_slot __lsm_ro_after_init;
>> +
>>  /**
>>   * security_add_hooks - Add a modules hooks to the hook lists.
>>   * @hooks: the hooks to add
>>   * @count: the number of hooks to add
>> - * @lsm: the name of the security module
>> + * @lsmid: the identification information for the security module
>>   *
>>   * Each LSM has to register its hooks with the infrastructure.
>> + * If the LSM is using hooks that export secids allocate a slot
>> + * for it in the lsmblob.
>>   */
>>  void __init security_add_hooks(struct security_hook_list *hooks, int count,
>> -				char *lsm)
>> +			       struct lsm_id *lsmid)
>>  {
>>  	int i;
>>  
> Could you add a WARN_ON(!lsmid->slot || !lsmid->name) here?

Yes. That's reasonable.

>
>
>> +	if (lsmid->slot == LSMBLOB_NEEDED) {
>> +		if (lsm_slot >= LSMBLOB_ENTRIES)
>> +			panic("%s Too many LSMs registered.\n", __func__);
>> +		lsmid->slot = lsm_slot++;
>> +		init_debug("%s assigned lsmblob slot %d\n", lsmid->lsm,
>> +			   lsmid->slot);
>> +	}
>> +
>>  	for (i = 0; i < count; i++) {
>> -		hooks[i].lsm = lsm;
>> +		hooks[i].lsmid = lsmid;
>>  		hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
>>  	}
>>  

Re: [PATCH v26 02/25] LSM: Add the lsmblob data structure.

[Mickaël Salaün]

On 26/05/2021 01:52, Casey Schaufler wrote:
> On 5/22/2021 1:39 AM, Mickaël Salaün wrote:
>> I like this design but there is an issue with Landlock though, see below.
>>
>> On 13/05/2021 22:07, Casey Schaufler wrote:
>>> When more than one security module is exporting data to
>>> audit and networking sub-systems a single 32 bit integer
>>> is no longer sufficient to represent the data. Add a
>>> structure to be used instead.
>>>
>>> The lsmblob structure is currently an array of
>>> u32 "secids". There is an entry for each of the
>>> security modules built into the system that would
>>> use secids if active. The system assigns the module
>>> a "slot" when it registers hooks. If modules are
>>> compiled in but not registered there will be unused
>>> slots.
>>>
>>> A new lsm_id structure, which contains the name
>>> of the LSM and its slot number, is created. There
>>> is an instance for each LSM, which assigns the name
>>> and passes it to the infrastructure to set the slot.
>>>
>>> The audit rules data is expanded to use an array of
>>> security module data rather than a single instance.
>>> Because IMA uses the audit rule functions it is
>>> affected as well.
>>>
>>> Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
>>> Acked-by: Paul Moore <paul@paul-moore.com>
>>> Acked-by: John Johansen <john.johansen@canonical.com>
>>> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
>>> Cc: <bpf@vger.kernel.org>
>>> Cc: linux-audit@redhat.com
>>> Cc: linux-security-module@vger.kernel.org
>>> Cc: selinux@vger.kernel.org
>>> To: Mimi Zohar <zohar@linux.ibm.com>
>>> To: Mickaël Salaün <mic@linux.microsoft.com>
>>> ---
>>>  include/linux/audit.h               |  4 +-
>>>  include/linux/lsm_hooks.h           | 12 ++++-
>>>  include/linux/security.h            | 67 +++++++++++++++++++++++++--
>>>  kernel/auditfilter.c                | 24 +++++-----
>>>  kernel/auditsc.c                    | 13 +++---
>>>  security/apparmor/lsm.c             |  7 ++-
>>>  security/bpf/hooks.c                | 12 ++++-
>>>  security/commoncap.c                |  7 ++-
>>>  security/integrity/ima/ima_policy.c | 40 +++++++++++-----
>>>  security/landlock/cred.c            |  2 +-
>>>  security/landlock/fs.c              |  2 +-
>>>  security/landlock/ptrace.c          |  2 +-
>>>  security/landlock/setup.c           |  4 ++
>>>  security/landlock/setup.h           |  1 +
>>>  security/loadpin/loadpin.c          |  8 +++-
>>>  security/lockdown/lockdown.c        |  7 ++-
>>>  security/safesetid/lsm.c            |  8 +++-
>>>  security/security.c                 | 72 ++++++++++++++++++++++++-----
>>>  security/selinux/hooks.c            |  8 +++-
>>>  security/smack/smack_lsm.c          |  7 ++-
>>>  security/tomoyo/tomoyo.c            |  8 +++-
>>>  security/yama/yama_lsm.c            |  7 ++-
>>>  22 files changed, 262 insertions(+), 60 deletions(-)
>>>
>> [...]
>>
>>> diff --git a/security/landlock/setup.c b/security/landlock/setup.c
>>> index f8e8e980454c..4a12666a4090 100644
>>> --- a/security/landlock/setup.c
>>> +++ b/security/landlock/setup.c
>>> @@ -23,6 +23,10 @@ struct lsm_blob_sizes landlock_blob_sizes __lsm_ro_after_init = {
>>>  	.lbs_superblock = sizeof(struct landlock_superblock_security),
>>>  };
>>>  
>>> +struct lsm_id landlock_lsmid __lsm_ro_after_init = {
>>> +	.lsm = LANDLOCK_NAME,
>> It is missing: .slot = LSMBLOB_NEEDED,
> 
> Sorry for the delay.
> 
> Landlock does not provide any of the hooks that use a struct lsmblob.
> That would be secid_to_secctx, secctx_to_secid, inode_getsecid,
> cred_getsecid, kernel_act_as task_getsecid_subj task_getsecid_obj and
> ipc_getsecid. Setting .slot = LSMBLOB_NEEDED indicates that the LSM
> uses a slot in struct lsmblob. Landlock does not need a slot.

Indeed, the (generic) "blob" name misled me. Would it make sense to use
a name with "secid" in it instead?

Shouldn't the slot field be set to LSMBLOB_NOT_NEEDED (-3) then (instead
of the implicit 0)?

> 
>>
>> You can run the Landlock tests please?
>> make -C tools/testing/selftests TARGETS=landlock gen_tar
>> tar -xf kselftest.tar.gz && ./run_kselftest.sh
> 
> Sure. I'll add them to my routine.

Thanks.

> 
>>
>>
>>> +};
>>> +
>>>  static int __init landlock_init(void)
>>>  {
>>>  	landlock_add_cred_hooks();
>> [...]
>>
>>> diff --git a/security/security.c b/security/security.c
>>> index e12a7c463468..a3276deb1b8a 100644
>>> --- a/security/security.c
>>> +++ b/security/security.c
>>> @@ -344,6 +344,7 @@ static void __init ordered_lsm_init(void)
>>>  	init_debug("sock blob size       = %d\n", blob_sizes.lbs_sock);
>>>  	init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock);
>>>  	init_debug("task blob size       = %d\n", blob_sizes.lbs_task);
>>> +	init_debug("lsmblob size         = %zu\n", sizeof(struct lsmblob));
>>>  
>>>  	/*
>>>  	 * Create any kmem_caches needed for blobs
>>> @@ -471,21 +472,36 @@ static int lsm_append(const char *new, char **result)
>>>  	return 0;
>>>  }
>>>  
>>> +/*
>>> + * Current index to use while initializing the lsmblob secid list.
>>> + */
>>> +static int lsm_slot __lsm_ro_after_init;
>>> +
>>>  /**
>>>   * security_add_hooks - Add a modules hooks to the hook lists.
>>>   * @hooks: the hooks to add
>>>   * @count: the number of hooks to add
>>> - * @lsm: the name of the security module
>>> + * @lsmid: the identification information for the security module
>>>   *
>>>   * Each LSM has to register its hooks with the infrastructure.
>>> + * If the LSM is using hooks that export secids allocate a slot
>>> + * for it in the lsmblob.
>>>   */
>>>  void __init security_add_hooks(struct security_hook_list *hooks, int count,
>>> -				char *lsm)
>>> +			       struct lsm_id *lsmid)
>>>  {
>>>  	int i;
>>>  
>> Could you add a WARN_ON(!lsmid->slot || !lsmid->name) here?
> 
> Yes. That's reasonable.

I guess my above comment makes sense if lsmid->slot should not be zero
but LSMBLOB_NOT_NEEDED instead, otherwise the Landlock lsmid would throw
a warning.

> 
>>
>>
>>> +	if (lsmid->slot == LSMBLOB_NEEDED) {
>>> +		if (lsm_slot >= LSMBLOB_ENTRIES)
>>> +			panic("%s Too many LSMs registered.\n", __func__);
>>> +		lsmid->slot = lsm_slot++;
>>> +		init_debug("%s assigned lsmblob slot %d\n", lsmid->lsm,
>>> +			   lsmid->slot);
>>> +	}
>>> +
>>>  	for (i = 0; i < count; i++) {
>>> -		hooks[i].lsm = lsm;
>>> +		hooks[i].lsmid = lsmid;
>>>  		hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
>>>  	}
>>>  
> 

[PATCH v26 03/25] LSM: provide lsm name and id slot mappings

[Casey Schaufler]

Provide interfaces to map LSM slot numbers and LSM names.
Update the LSM registration code to save this information.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/security.h |  4 ++++
 security/security.c      | 45 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/include/linux/security.h b/include/linux/security.h
index 62588bc522ba..ca9485105f00 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -192,6 +192,10 @@ static inline bool lsmblob_equal(struct lsmblob *bloba, struct lsmblob *blobb)
 	return !memcmp(bloba, blobb, sizeof(*bloba));
 }
 
+/* Map lsm names to blob slot numbers */
+extern int lsm_name_to_slot(char *name);
+extern const char *lsm_slot_to_name(int slot);
+
 /* These functions are in security/commoncap.c */
 extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
 		       int cap, unsigned int opts);
diff --git a/security/security.c b/security/security.c
index a3276deb1b8a..9471bcecc052 100644
--- a/security/security.c
+++ b/security/security.c
@@ -476,6 +476,50 @@ static int lsm_append(const char *new, char **result)
  * Current index to use while initializing the lsmblob secid list.
  */
 static int lsm_slot __lsm_ro_after_init;
+static struct lsm_id *lsm_slotlist[LSMBLOB_ENTRIES] __lsm_ro_after_init;
+
+/**
+ * lsm_name_to_slot - Report the slot number for a security module
+ * @name: name of the security module
+ *
+ * Look up the slot number for the named security module.
+ * Returns the slot number or LSMBLOB_INVALID if @name is not
+ * a registered security module name.
+ */
+int lsm_name_to_slot(char *name)
+{
+	int i;
+
+	for (i = 0; i < lsm_slot; i++)
+		if (strcmp(lsm_slotlist[i]->lsm, name) == 0)
+			return i;
+
+	return LSMBLOB_INVALID;
+}
+
+/**
+ * lsm_slot_to_name - Get the name of the security module in a slot
+ * @slot: index into the interface LSM slot list.
+ *
+ * Provide the name of the security module associated with
+ * a interface LSM slot.
+ *
+ * If @slot is LSMBLOB_INVALID return the value
+ * for slot 0 if it has been set, otherwise NULL.
+ *
+ * Returns a pointer to the name string or NULL.
+ */
+const char *lsm_slot_to_name(int slot)
+{
+	if (slot == LSMBLOB_INVALID)
+		slot = 0;
+	else if (slot >= LSMBLOB_ENTRIES || slot < 0)
+		return NULL;
+
+	if (lsm_slotlist[slot] == NULL)
+		return NULL;
+	return lsm_slotlist[slot]->lsm;
+}
 
 /**
  * security_add_hooks - Add a modules hooks to the hook lists.
@@ -495,6 +539,7 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
 	if (lsmid->slot == LSMBLOB_NEEDED) {
 		if (lsm_slot >= LSMBLOB_ENTRIES)
 			panic("%s Too many LSMs registered.\n", __func__);
+		lsm_slotlist[lsm_slot] = lsmid;
 		lsmid->slot = lsm_slot++;
 		init_debug("%s assigned lsmblob slot %d\n", lsmid->lsm,
 			   lsmid->slot);
-- 
2.29.2

Re: [PATCH v26 03/25] LSM: provide lsm name and id slot mappings

[Kees Cook]

On Thu, May 13, 2021 at 01:07:45PM -0700, Casey Schaufler wrote:
> Provide interfaces to map LSM slot numbers and LSM names.
> Update the LSM registration code to save this information.
> 
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

Seems a reasonable set of utilities. :)

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

Re: [PATCH v26 03/25] LSM: provide lsm name and id slot mappings

[Paul Moore]

On Thu, May 13, 2021 at 4:11 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
>
> Provide interfaces to map LSM slot numbers and LSM names.
> Update the LSM registration code to save this information.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> ---
>  include/linux/security.h |  4 ++++
>  security/security.c      | 45 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 49 insertions(+)

Acked-by: Paul Moore <paul@paul-moore.com>


--
paul moore
www.paul-moore.com

[PATCH v26 04/25] IMA: avoid label collisions with stacked LSMs

[Casey Schaufler]

Integrity measurement may filter on security module information
and needs to be clear in the case of multiple active security
modules which applies. Provide a boot option ima_rules_lsm= to
allow the user to specify an active securty module to apply
filters to. If not specified, use the first registered module
that supports the audit_rule_match() LSM hook. Allow the user
to specify in the IMA policy an lsm= option to specify the
security module to use for a particular rule.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
To: Mimi Zohar <zohar@linux.ibm.com>
To: linux-integrity@vger.kernel.org
---
 Documentation/ABI/testing/ima_policy |  8 ++-
 security/integrity/ima/ima_policy.c  | 77 ++++++++++++++++++++--------
 2 files changed, 62 insertions(+), 23 deletions(-)

diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
index 070779e8d836..84dd19bc4344 100644
--- a/Documentation/ABI/testing/ima_policy
+++ b/Documentation/ABI/testing/ima_policy
@@ -25,7 +25,7 @@ Description:
 			base:	[[func=] [mask=] [fsmagic=] [fsuuid=] [uid=]
 				[euid=] [fowner=] [fsname=]]
 			lsm:	[[subj_user=] [subj_role=] [subj_type=]
-				 [obj_user=] [obj_role=] [obj_type=]]
+				 [obj_user=] [obj_role=] [obj_type=] [lsm=]]
 			option:	[[appraise_type=]] [template=] [permit_directio]
 				[appraise_flag=] [keyrings=]
 		  base:
@@ -117,6 +117,12 @@ Description:
 
 			measure subj_user=_ func=FILE_CHECK mask=MAY_READ
 
+		It is possible to explicitly specify which security
+		module a rule applies to using lsm=.  If the security
+		modules specified is not active on the system the rule
+		will be rejected.  If lsm= is not specified the first
+		security module registered on the system will be assumed.
+
 		Example of measure rules using alternate PCRs::
 
 			measure func=KEXEC_KERNEL_CHECK pcr=4
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 5c40677e881c..d804b9a0dd95 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -79,8 +79,9 @@ struct ima_rule_entry {
 	bool (*uid_op)(kuid_t, kuid_t);    /* Handlers for operators       */
 	bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
 	int pcr;
+	int which_lsm; /* which of the rules to use */
 	struct {
-		void *rules[LSMBLOB_ENTRIES]; /* LSM file metadata specific */
+		void *rule;	/* LSM file metadata specific */
 		char *args_p;	/* audit value */
 		int type;	/* audit type */
 	} lsm[MAX_LSM_RULES];
@@ -92,17 +93,15 @@ struct ima_rule_entry {
 
 /**
  * ima_lsm_isset - Is a rule set for any of the active security modules
- * @rules: The set of IMA rules to check
+ * @entry: the rule entry to examine
+ * @lsm_rule: the specific rule type in question
  *
- * If a rule is set for any LSM return true, otherwise return false.
+ * If a rule is set return true, otherwise return false.
  */
-static inline bool ima_lsm_isset(void *rules[])
+static inline bool ima_lsm_isset(struct ima_rule_entry *entry, int lsm_rule)
 {
-	int i;
-
-	for (i = 0; i < LSMBLOB_ENTRIES; i++)
-		if (rules[i])
-			return true;
+	if (entry->lsm[lsm_rule].rule)
+		return true;
 	return false;
 }
 
@@ -282,6 +281,20 @@ static int __init default_appraise_policy_setup(char *str)
 }
 __setup("ima_appraise_tcb", default_appraise_policy_setup);
 
+static int ima_rules_lsm __ro_after_init;
+
+static int __init ima_rules_lsm_init(char *str)
+{
+	ima_rules_lsm = lsm_name_to_slot(str);
+	if (ima_rules_lsm < 0) {
+		ima_rules_lsm = 0;
+		pr_err("rule lsm \"%s\" not registered", str);
+	}
+
+	return 1;
+}
+__setup("ima_rules_lsm=", ima_rules_lsm_init);
+
 static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
 {
 	struct ima_rule_opt_list *opt_list;
@@ -351,11 +364,10 @@ static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
 static void ima_lsm_free_rule(struct ima_rule_entry *entry)
 {
 	int i;
-	int r;
 
 	for (i = 0; i < MAX_LSM_RULES; i++) {
-		for (r = 0; r < LSMBLOB_ENTRIES; r++)
-			ima_filter_rule_free(entry->lsm[i].rules[r]);
+		if (entry->lsm[i].rule)
+			ima_filter_rule_free(entry->lsm[i].rule);
 		kfree(entry->lsm[i].args_p);
 	}
 }
@@ -406,8 +418,8 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
 
 		ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
 				     nentry->lsm[i].args_p,
-				     &nentry->lsm[i].rules[0]);
-		if (!ima_lsm_isset(nentry->lsm[i].rules))
+				     &nentry->lsm[i].rule);
+		if (!ima_lsm_isset(nentry, i))
 			pr_warn("rule for LSM \'%s\' is undefined\n",
 				nentry->lsm[i].args_p);
 	}
@@ -596,7 +608,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
 		int rc = 0;
 		u32 osid;
 
-		if (!ima_lsm_isset(rule->lsm[i].rules)) {
+		if (!ima_lsm_isset(rule, i)) {
 			if (!rule->lsm[i].args_p)
 				continue;
 			else
@@ -609,14 +621,14 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
 			security_inode_getsecid(inode, &osid);
 			rc = ima_filter_rule_match(osid, rule->lsm[i].type,
 						   Audit_equal,
-						   rule->lsm[i].rules);
+						   rule->lsm[i].rule);
 			break;
 		case LSM_SUBJ_USER:
 		case LSM_SUBJ_ROLE:
 		case LSM_SUBJ_TYPE:
 			rc = ima_filter_rule_match(secid, rule->lsm[i].type,
 						   Audit_equal,
-						   rule->lsm[i].rules);
+						   rule->lsm[i].rule);
 			break;
 		default:
 			break;
@@ -966,7 +978,7 @@ enum {
 	Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
 	Opt_appraise_type, Opt_appraise_flag,
 	Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
-	Opt_label, Opt_err
+	Opt_lsm, Opt_label, Opt_err
 };
 
 static const match_table_t policy_tokens = {
@@ -1004,6 +1016,7 @@ static const match_table_t policy_tokens = {
 	{Opt_template, "template=%s"},
 	{Opt_keyrings, "keyrings=%s"},
 	{Opt_label, "label=%s"},
+	{Opt_lsm, "lsm=%s"},
 	{Opt_err, NULL}
 };
 
@@ -1012,7 +1025,7 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 {
 	int result;
 
-	if (ima_lsm_isset(entry->lsm[lsm_rule].rules))
+	if (ima_lsm_isset(entry, lsm_rule))
 		return -EINVAL;
 
 	entry->lsm[lsm_rule].args_p = match_strdup(args);
@@ -1022,8 +1035,8 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 	entry->lsm[lsm_rule].type = audit_type;
 	result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
 				      entry->lsm[lsm_rule].args_p,
-				      &entry->lsm[lsm_rule].rules[0]);
-	if (!ima_lsm_isset(entry->lsm[lsm_rule].rules)) {
+				      &entry->lsm[lsm_rule].rule);
+	if (!ima_lsm_isset(entry, lsm_rule)) {
 		pr_warn("rule for LSM \'%s\' is undefined\n",
 			entry->lsm[lsm_rule].args_p);
 
@@ -1561,6 +1574,19 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 						 &(template_desc->num_fields));
 			entry->template = template_desc;
 			break;
+		case Opt_lsm:
+			result = lsm_name_to_slot(args[0].from);
+			if (result == LSMBLOB_INVALID) {
+				int i;
+
+				for (i = 0; i < MAX_LSM_RULES; i++)
+					entry->lsm[i].args_p = NULL;
+				result = -EINVAL;
+				break;
+			}
+			entry->which_lsm = result;
+			result = 0;
+			break;
 		case Opt_err:
 			ima_log_string(ab, "UNKNOWN", p);
 			result = -EINVAL;
@@ -1597,6 +1623,7 @@ ssize_t ima_parse_add_rule(char *rule)
 	struct ima_rule_entry *entry;
 	ssize_t result, len;
 	int audit_info = 0;
+	int i;
 
 	p = strsep(&rule, "\n");
 	len = strlen(p) + 1;
@@ -1614,6 +1641,9 @@ ssize_t ima_parse_add_rule(char *rule)
 
 	INIT_LIST_HEAD(&entry->list);
 
+	for (i = 0; i < MAX_LSM_RULES; i++)
+		entry->which_lsm = ima_rules_lsm;
+
 	result = ima_parse_rule(p, entry);
 	if (result) {
 		ima_free_rule(entry);
@@ -1830,7 +1860,7 @@ int ima_policy_show(struct seq_file *m, void *v)
 	}
 
 	for (i = 0; i < MAX_LSM_RULES; i++) {
-		if (ima_lsm_isset(entry->lsm[i].rules)) {
+		if (ima_lsm_isset(entry, i)) {
 			switch (i) {
 			case LSM_OBJ_USER:
 				seq_printf(m, pt(Opt_obj_user),
@@ -1872,6 +1902,9 @@ int ima_policy_show(struct seq_file *m, void *v)
 		seq_puts(m, "appraise_flag=check_blacklist ");
 	if (entry->flags & IMA_PERMIT_DIRECTIO)
 		seq_puts(m, "permit_directio ");
+	if (entry->which_lsm >= 0)
+		seq_printf(m, pt(Opt_lsm),
+			   lsm_slot_to_name(entry->which_lsm));
 	rcu_read_unlock();
 	seq_puts(m, "\n");
 	return 0;
-- 
2.29.2

Re: [PATCH v26 04/25] IMA: avoid label collisions with stacked LSMs

[Kees Cook]

On Thu, May 13, 2021 at 01:07:46PM -0700, Casey Schaufler wrote:
> Integrity measurement may filter on security module information
> and needs to be clear in the case of multiple active security
> modules which applies. Provide a boot option ima_rules_lsm= to
> allow the user to specify an active securty module to apply
> filters to. If not specified, use the first registered module
> that supports the audit_rule_match() LSM hook. Allow the user
> to specify in the IMA policy an lsm= option to specify the
> security module to use for a particular rule.
> 
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> To: Mimi Zohar <zohar@linux.ibm.com>
> To: linux-integrity@vger.kernel.org
> ---
>  Documentation/ABI/testing/ima_policy |  8 ++-
>  security/integrity/ima/ima_policy.c  | 77 ++++++++++++++++++++--------
>  2 files changed, 62 insertions(+), 23 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
> index 070779e8d836..84dd19bc4344 100644
> --- a/Documentation/ABI/testing/ima_policy
> +++ b/Documentation/ABI/testing/ima_policy
> @@ -25,7 +25,7 @@ Description:
>  			base:	[[func=] [mask=] [fsmagic=] [fsuuid=] [uid=]
>  				[euid=] [fowner=] [fsname=]]
>  			lsm:	[[subj_user=] [subj_role=] [subj_type=]
> -				 [obj_user=] [obj_role=] [obj_type=]]
> +				 [obj_user=] [obj_role=] [obj_type=] [lsm=]]
>  			option:	[[appraise_type=]] [template=] [permit_directio]
>  				[appraise_flag=] [keyrings=]
>  		  base:
> @@ -117,6 +117,12 @@ Description:
>  
>  			measure subj_user=_ func=FILE_CHECK mask=MAY_READ
>  
> +		It is possible to explicitly specify which security
> +		module a rule applies to using lsm=.  If the security
> +		modules specified is not active on the system the rule
> +		will be rejected.  If lsm= is not specified the first
> +		security module registered on the system will be assumed.
> +
>  		Example of measure rules using alternate PCRs::
>  
>  			measure func=KEXEC_KERNEL_CHECK pcr=4
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index 5c40677e881c..d804b9a0dd95 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -79,8 +79,9 @@ struct ima_rule_entry {
>  	bool (*uid_op)(kuid_t, kuid_t);    /* Handlers for operators       */
>  	bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
>  	int pcr;
> +	int which_lsm; /* which of the rules to use */
>  	struct {
> -		void *rules[LSMBLOB_ENTRIES]; /* LSM file metadata specific */
> +		void *rule;	/* LSM file metadata specific */
>  		char *args_p;	/* audit value */
>  		int type;	/* audit type */
>  	} lsm[MAX_LSM_RULES];
> @@ -92,17 +93,15 @@ struct ima_rule_entry {
>  
>  /**
>   * ima_lsm_isset - Is a rule set for any of the active security modules
> - * @rules: The set of IMA rules to check
> + * @entry: the rule entry to examine
> + * @lsm_rule: the specific rule type in question
>   *
> - * If a rule is set for any LSM return true, otherwise return false.
> + * If a rule is set return true, otherwise return false.
>   */
> -static inline bool ima_lsm_isset(void *rules[])
> +static inline bool ima_lsm_isset(struct ima_rule_entry *entry, int lsm_rule)
>  {
> -	int i;
> -
> -	for (i = 0; i < LSMBLOB_ENTRIES; i++)
> -		if (rules[i])
> -			return true;
> +	if (entry->lsm[lsm_rule].rule)
> +		return true;

I'd be happier if this retained the MAX_LSM_RULES bounds-check.

>  	return false;
>  }
>  
> @@ -282,6 +281,20 @@ static int __init default_appraise_policy_setup(char *str)
>  }
>  __setup("ima_appraise_tcb", default_appraise_policy_setup);
>  
> +static int ima_rules_lsm __ro_after_init;
> +
> +static int __init ima_rules_lsm_init(char *str)
> +{
> +	ima_rules_lsm = lsm_name_to_slot(str);
> +	if (ima_rules_lsm < 0) {
> +		ima_rules_lsm = 0;
> +		pr_err("rule lsm \"%s\" not registered", str);
> +	}
> +
> +	return 1;
> +}
> +__setup("ima_rules_lsm=", ima_rules_lsm_init);
> +
>  static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
>  {
>  	struct ima_rule_opt_list *opt_list;
> @@ -351,11 +364,10 @@ static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
>  static void ima_lsm_free_rule(struct ima_rule_entry *entry)
>  {
>  	int i;
> -	int r;
>  
>  	for (i = 0; i < MAX_LSM_RULES; i++) {
> -		for (r = 0; r < LSMBLOB_ENTRIES; r++)
> -			ima_filter_rule_free(entry->lsm[i].rules[r]);
> +		if (entry->lsm[i].rule)
> +			ima_filter_rule_free(entry->lsm[i].rule);
>  		kfree(entry->lsm[i].args_p);
>  	}
>  }
> @@ -406,8 +418,8 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
>  
>  		ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
>  				     nentry->lsm[i].args_p,
> -				     &nentry->lsm[i].rules[0]);
> -		if (!ima_lsm_isset(nentry->lsm[i].rules))
> +				     &nentry->lsm[i].rule);
> +		if (!ima_lsm_isset(nentry, i))
>  			pr_warn("rule for LSM \'%s\' is undefined\n",
>  				nentry->lsm[i].args_p);
>  	}
> @@ -596,7 +608,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
>  		int rc = 0;
>  		u32 osid;
>  
> -		if (!ima_lsm_isset(rule->lsm[i].rules)) {
> +		if (!ima_lsm_isset(rule, i)) {
>  			if (!rule->lsm[i].args_p)
>  				continue;
>  			else
> @@ -609,14 +621,14 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
>  			security_inode_getsecid(inode, &osid);
>  			rc = ima_filter_rule_match(osid, rule->lsm[i].type,
>  						   Audit_equal,
> -						   rule->lsm[i].rules);
> +						   rule->lsm[i].rule);
>  			break;
>  		case LSM_SUBJ_USER:
>  		case LSM_SUBJ_ROLE:
>  		case LSM_SUBJ_TYPE:
>  			rc = ima_filter_rule_match(secid, rule->lsm[i].type,
>  						   Audit_equal,
> -						   rule->lsm[i].rules);
> +						   rule->lsm[i].rule);
>  			break;
>  		default:
>  			break;
> @@ -966,7 +978,7 @@ enum {
>  	Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
>  	Opt_appraise_type, Opt_appraise_flag,
>  	Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
> -	Opt_label, Opt_err
> +	Opt_lsm, Opt_label, Opt_err
>  };
>  
>  static const match_table_t policy_tokens = {
> @@ -1004,6 +1016,7 @@ static const match_table_t policy_tokens = {
>  	{Opt_template, "template=%s"},
>  	{Opt_keyrings, "keyrings=%s"},
>  	{Opt_label, "label=%s"},
> +	{Opt_lsm, "lsm=%s"},
>  	{Opt_err, NULL}
>  };
>  
> @@ -1012,7 +1025,7 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
>  {
>  	int result;
>  
> -	if (ima_lsm_isset(entry->lsm[lsm_rule].rules))
> +	if (ima_lsm_isset(entry, lsm_rule))
>  		return -EINVAL;
>  
>  	entry->lsm[lsm_rule].args_p = match_strdup(args);
> @@ -1022,8 +1035,8 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
>  	entry->lsm[lsm_rule].type = audit_type;
>  	result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
>  				      entry->lsm[lsm_rule].args_p,
> -				      &entry->lsm[lsm_rule].rules[0]);
> -	if (!ima_lsm_isset(entry->lsm[lsm_rule].rules)) {
> +				      &entry->lsm[lsm_rule].rule);
> +	if (!ima_lsm_isset(entry, lsm_rule)) {
>  		pr_warn("rule for LSM \'%s\' is undefined\n",
>  			entry->lsm[lsm_rule].args_p);
>  
> @@ -1561,6 +1574,19 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
>  						 &(template_desc->num_fields));
>  			entry->template = template_desc;
>  			break;
> +		case Opt_lsm:
> +			result = lsm_name_to_slot(args[0].from);
> +			if (result == LSMBLOB_INVALID) {
> +				int i;
> +
> +				for (i = 0; i < MAX_LSM_RULES; i++)
> +					entry->lsm[i].args_p = NULL;
> +				result = -EINVAL;
> +				break;
> +			}
> +			entry->which_lsm = result;
> +			result = 0;
> +			break;
>  		case Opt_err:
>  			ima_log_string(ab, "UNKNOWN", p);
>  			result = -EINVAL;
> @@ -1597,6 +1623,7 @@ ssize_t ima_parse_add_rule(char *rule)
>  	struct ima_rule_entry *entry;
>  	ssize_t result, len;
>  	int audit_info = 0;
> +	int i;
>  
>  	p = strsep(&rule, "\n");
>  	len = strlen(p) + 1;
> @@ -1614,6 +1641,9 @@ ssize_t ima_parse_add_rule(char *rule)
>  
>  	INIT_LIST_HEAD(&entry->list);
>  
> +	for (i = 0; i < MAX_LSM_RULES; i++)
> +		entry->which_lsm = ima_rules_lsm;
> +
>  	result = ima_parse_rule(p, entry);
>  	if (result) {
>  		ima_free_rule(entry);
> @@ -1830,7 +1860,7 @@ int ima_policy_show(struct seq_file *m, void *v)
>  	}
>  
>  	for (i = 0; i < MAX_LSM_RULES; i++) {
> -		if (ima_lsm_isset(entry->lsm[i].rules)) {
> +		if (ima_lsm_isset(entry, i)) {
>  			switch (i) {
>  			case LSM_OBJ_USER:
>  				seq_printf(m, pt(Opt_obj_user),
> @@ -1872,6 +1902,9 @@ int ima_policy_show(struct seq_file *m, void *v)
>  		seq_puts(m, "appraise_flag=check_blacklist ");
>  	if (entry->flags & IMA_PERMIT_DIRECTIO)
>  		seq_puts(m, "permit_directio ");
> +	if (entry->which_lsm >= 0)
> +		seq_printf(m, pt(Opt_lsm),
> +			   lsm_slot_to_name(entry->which_lsm));
>  	rcu_read_unlock();
>  	seq_puts(m, "\n");
>  	return 0;
> -- 
> 2.29.2
> 

Otherwise, this looks correct. With bounds checking:

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

[PATCH v26 05/25] LSM: Use lsmblob in security_audit_rule_match

[Casey Schaufler]

Change the secid parameter of security_audit_rule_match
to a lsmblob structure pointer. Pass the entry from the
lsmblob structure for the approprite slot to the LSM hook.

Change the users of security_audit_rule_match to use the
lsmblob instead of a u32. The scaffolding function lsmblob_init()
fills the blob with the value of the old secid, ensuring that
it is available to the appropriate module hook. The sources of
the secid, security_task_getsecid() and security_inode_getsecid(),
will be converted to use the blob structure later in the series.
At the point the use of lsmblob_init() is dropped.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-audit@redhat.com
Cc: linux-integrity@vger.kernel.org
To: Mimi Zohar <zohar@linux.ibm.com>
---
 include/linux/security.h            |  7 ++++---
 kernel/auditfilter.c                |  6 ++++--
 kernel/auditsc.c                    | 16 +++++++++++-----
 security/integrity/ima/ima.h        |  4 ++--
 security/integrity/ima/ima_policy.c |  7 +++++--
 security/security.c                 | 10 ++++++++--
 6 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index ca9485105f00..916a0f606035 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1944,7 +1944,8 @@ static inline int security_key_getsecurity(struct key *key, char **_buffer)
 #ifdef CONFIG_SECURITY
 int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule);
 int security_audit_rule_known(struct audit_krule *krule);
-int security_audit_rule_match(u32 secid, u32 field, u32 op, void **lsmrule);
+int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
+			      void **lsmrule);
 void security_audit_rule_free(void **lsmrule);
 
 #else
@@ -1960,8 +1961,8 @@ static inline int security_audit_rule_known(struct audit_krule *krule)
 	return 0;
 }
 
-static inline int security_audit_rule_match(u32 secid, u32 field, u32 op,
-					    void **lsmrule)
+static inline int security_audit_rule_match(struct lsmblob *blob, u32 field,
+					    u32 op, void **lsmrule)
 {
 	return 0;
 }
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index a2340e81cfa7..6a04d762d272 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1331,6 +1331,7 @@ int audit_filter(int msgtype, unsigned int listtype)
 			struct audit_field *f = &e->rule.fields[i];
 			pid_t pid;
 			u32 sid;
+			struct lsmblob blob;
 
 			switch (f->type) {
 			case AUDIT_PID:
@@ -1362,8 +1363,9 @@ int audit_filter(int msgtype, unsigned int listtype)
 				if (f->lsm_isset) {
 					security_task_getsecid_subj(current,
 								    &sid);
-					result = security_audit_rule_match(sid,
-						   f->type, f->op,
+					lsmblob_init(&blob, sid);
+					result = security_audit_rule_match(
+						   &blob, f->type, f->op,
 						   f->lsm_rules);
 				}
 				break;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 392afe3e2fd6..71d894dcdc01 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -472,6 +472,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 	const struct cred *cred;
 	int i, need_sid = 1;
 	u32 sid;
+	struct lsmblob blob;
 	unsigned int sessionid;
 
 	cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
@@ -670,8 +671,10 @@ static int audit_filter_rules(struct task_struct *tsk,
 					security_task_getsecid_subj(tsk, &sid);
 					need_sid = 0;
 				}
-				result = security_audit_rule_match(sid, f->type,
-							f->op, f->lsm_rules);
+				lsmblob_init(&blob, sid);
+				result = security_audit_rule_match(&blob,
+							f->type, f->op,
+							f->lsm_rules);
 			}
 			break;
 		case AUDIT_OBJ_USER:
@@ -684,15 +687,17 @@ static int audit_filter_rules(struct task_struct *tsk,
 			if (f->lsm_isset) {
 				/* Find files that match */
 				if (name) {
+					lsmblob_init(&blob, name->osid);
 					result = security_audit_rule_match(
-								name->osid,
+								&blob,
 								f->type,
 								f->op,
 								f->lsm_rules);
 				} else if (ctx) {
 					list_for_each_entry(n, &ctx->names_list, list) {
+						lsmblob_init(&blob, name->osid);
 						if (security_audit_rule_match(
-								n->osid,
+								&blob,
 								f->type,
 								f->op,
 								f->lsm_rules)) {
@@ -704,7 +709,8 @@ static int audit_filter_rules(struct task_struct *tsk,
 				/* Find ipc objects that match */
 				if (!ctx || ctx->type != AUDIT_IPC)
 					break;
-				if (security_audit_rule_match(ctx->ipc.osid,
+				lsmblob_init(&blob, ctx->ipc.osid);
+				if (security_audit_rule_match(&blob,
 							      f->type, f->op,
 							      f->lsm_rules))
 					++result;
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index f0e448ed1f9f..55f3bd4f0b01 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -433,8 +433,8 @@ static inline void ima_filter_rule_free(void *lsmrule)
 {
 }
 
-static inline int ima_filter_rule_match(u32 secid, u32 field, u32 op,
-					void *lsmrule)
+static inline int ima_filter_rule_match(struct lsmblob *blob, u32 field,
+					u32 op, void *lsmrule)
 {
 	return -EINVAL;
 }
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index d804b9a0dd95..a05841e1012b 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -607,6 +607,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
 	for (i = 0; i < MAX_LSM_RULES; i++) {
 		int rc = 0;
 		u32 osid;
+		struct lsmblob lsmdata;
 
 		if (!ima_lsm_isset(rule, i)) {
 			if (!rule->lsm[i].args_p)
@@ -619,14 +620,16 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
 		case LSM_OBJ_ROLE:
 		case LSM_OBJ_TYPE:
 			security_inode_getsecid(inode, &osid);
-			rc = ima_filter_rule_match(osid, rule->lsm[i].type,
+			lsmblob_init(&lsmdata, osid);
+			rc = ima_filter_rule_match(&lsmdata, rule->lsm[i].type,
 						   Audit_equal,
 						   rule->lsm[i].rule);
 			break;
 		case LSM_SUBJ_USER:
 		case LSM_SUBJ_ROLE:
 		case LSM_SUBJ_TYPE:
-			rc = ima_filter_rule_match(secid, rule->lsm[i].type,
+			lsmblob_init(&lsmdata, secid);
+			rc = ima_filter_rule_match(&lsmdata, rule->lsm[i].type,
 						   Audit_equal,
 						   rule->lsm[i].rule);
 			break;
diff --git a/security/security.c b/security/security.c
index 9471bcecc052..a5793b4bf684 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2669,11 +2669,14 @@ void security_audit_rule_free(void **lsmrule)
 	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_free, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
+		if (lsmrule[hp->lsmid->slot] == NULL)
+			continue;
 		hp->hook.audit_rule_free(lsmrule[hp->lsmid->slot]);
 	}
 }
 
-int security_audit_rule_match(u32 secid, u32 field, u32 op, void **lsmrule)
+int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
+			      void **lsmrule)
 {
 	struct security_hook_list *hp;
 	int rc;
@@ -2681,7 +2684,10 @@ int security_audit_rule_match(u32 secid, u32 field, u32 op, void **lsmrule)
 	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_match, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
-		rc = hp->hook.audit_rule_match(secid, field, op,
+		if (lsmrule[hp->lsmid->slot] == NULL)
+			continue;
+		rc = hp->hook.audit_rule_match(blob->secid[hp->lsmid->slot],
+					       field, op,
 					       &lsmrule[hp->lsmid->slot]);
 		if (rc)
 			return rc;
-- 
2.29.2

[PATCH v26 06/25] LSM: Use lsmblob in security_kernel_act_as

[Casey Schaufler]

Change the security_kernel_act_as interface to use a lsmblob
structure in place of the single u32 secid in support of
module stacking. Change its only caller, set_security_override,
to do the same. Change that one's only caller,
set_security_override_from_ctx, to call it with the new
parameter type.

The security module hook is unchanged, still taking a secid.
The infrastructure passes the correct entry from the lsmblob.
lsmblob_init() is used to fill the lsmblob structure, however
this will be removed later in the series when security_secctx_to_secid()
is updated to provide a lsmblob instead of a secid.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
To: David Howells <dhowells@redhat.com>
---
 include/linux/cred.h     |  3 ++-
 include/linux/security.h |  5 +++--
 kernel/cred.c            | 10 ++++++----
 security/security.c      | 14 ++++++++++++--
 4 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/include/linux/cred.h b/include/linux/cred.h
index 14971322e1a0..5a3f0fc3090d 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -18,6 +18,7 @@
 
 struct cred;
 struct inode;
+struct lsmblob;
 
 /*
  * COW Supplementary groups list
@@ -164,7 +165,7 @@ extern const struct cred *override_creds(const struct cred *);
 extern void revert_creds(const struct cred *);
 extern struct cred *prepare_kernel_cred(struct task_struct *);
 extern int change_create_files_as(struct cred *, struct inode *);
-extern int set_security_override(struct cred *, u32);
+extern int set_security_override(struct cred *, struct lsmblob *);
 extern int set_security_override_from_ctx(struct cred *, const char *);
 extern int set_create_files_as(struct cred *, struct inode *);
 extern int cred_fscmp(const struct cred *, const struct cred *);
diff --git a/include/linux/security.h b/include/linux/security.h
index 916a0f606035..5c664ba0fbc3 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -461,7 +461,7 @@ void security_cred_free(struct cred *cred);
 int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp);
 void security_transfer_creds(struct cred *new, const struct cred *old);
 void security_cred_getsecid(const struct cred *c, u32 *secid);
-int security_kernel_act_as(struct cred *new, u32 secid);
+int security_kernel_act_as(struct cred *new, struct lsmblob *blob);
 int security_kernel_create_files_as(struct cred *new, struct inode *inode);
 int security_kernel_module_request(char *kmod_name);
 int security_kernel_load_data(enum kernel_load_data_id id, bool contents);
@@ -1103,7 +1103,8 @@ static inline void security_transfer_creds(struct cred *new,
 {
 }
 
-static inline int security_kernel_act_as(struct cred *cred, u32 secid)
+static inline int security_kernel_act_as(struct cred *cred,
+					 struct lsmblob *blob)
 {
 	return 0;
 }
diff --git a/kernel/cred.c b/kernel/cred.c
index e1d274cd741b..ad845c99e2d1 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -733,14 +733,14 @@ EXPORT_SYMBOL(prepare_kernel_cred);
 /**
  * set_security_override - Set the security ID in a set of credentials
  * @new: The credentials to alter
- * @secid: The LSM security ID to set
+ * @blob: The LSM security information to set
  *
  * Set the LSM security ID in a set of credentials so that the subjective
  * security is overridden when an alternative set of credentials is used.
  */
-int set_security_override(struct cred *new, u32 secid)
+int set_security_override(struct cred *new, struct lsmblob *blob)
 {
-	return security_kernel_act_as(new, secid);
+	return security_kernel_act_as(new, blob);
 }
 EXPORT_SYMBOL(set_security_override);
 
@@ -756,6 +756,7 @@ EXPORT_SYMBOL(set_security_override);
  */
 int set_security_override_from_ctx(struct cred *new, const char *secctx)
 {
+	struct lsmblob blob;
 	u32 secid;
 	int ret;
 
@@ -763,7 +764,8 @@ int set_security_override_from_ctx(struct cred *new, const char *secctx)
 	if (ret < 0)
 		return ret;
 
-	return set_security_override(new, secid);
+	lsmblob_init(&blob, secid);
+	return set_security_override(new, &blob);
 }
 EXPORT_SYMBOL(set_security_override_from_ctx);
 
diff --git a/security/security.c b/security/security.c
index a5793b4bf684..6a8233d746d3 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1796,9 +1796,19 @@ void security_cred_getsecid(const struct cred *c, u32 *secid)
 }
 EXPORT_SYMBOL(security_cred_getsecid);
 
-int security_kernel_act_as(struct cred *new, u32 secid)
+int security_kernel_act_as(struct cred *new, struct lsmblob *blob)
 {
-	return call_int_hook(kernel_act_as, 0, new, secid);
+	struct security_hook_list *hp;
+	int rc;
+
+	hlist_for_each_entry(hp, &security_hook_heads.kernel_act_as, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		rc = hp->hook.kernel_act_as(new, blob->secid[hp->lsmid->slot]);
+		if (rc != 0)
+			return rc;
+	}
+	return 0;
 }
 
 int security_kernel_create_files_as(struct cred *new, struct inode *inode)
-- 
2.29.2

[PATCH v26 07/25] LSM: Use lsmblob in security_secctx_to_secid

[Casey Schaufler]

Change the security_secctx_to_secid interface to use a lsmblob
structure in place of the single u32 secid in support of
module stacking. Change its callers to do the same.

The security module hook is unchanged, still passing back a secid.
The infrastructure passes the correct entry from the lsmblob.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: netdev@vger.kernel.org
Cc: netfilter-devel@vger.kernel.org
To: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/linux/security.h          | 26 ++++++++++++++++++--
 kernel/cred.c                     |  4 +---
 net/netfilter/nft_meta.c          | 10 ++++----
 net/netfilter/xt_SECMARK.c        |  7 +++++-
 net/netlabel/netlabel_unlabeled.c | 23 +++++++++++-------
 security/security.c               | 40 ++++++++++++++++++++++++++-----
 6 files changed, 85 insertions(+), 25 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index 5c664ba0fbc3..dbb1e5f5b591 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -196,6 +196,27 @@ static inline bool lsmblob_equal(struct lsmblob *bloba, struct lsmblob *blobb)
 extern int lsm_name_to_slot(char *name);
 extern const char *lsm_slot_to_name(int slot);
 
+/**
+ * lsmblob_value - find the first non-zero value in an lsmblob structure.
+ * @blob: Pointer to the data
+ *
+ * This needs to be used with extreme caution, as the cases where
+ * it is appropriate are rare.
+ *
+ * Return the first secid value set in the lsmblob.
+ * There should only be one.
+ */
+static inline u32 lsmblob_value(const struct lsmblob *blob)
+{
+	int i;
+
+	for (i = 0; i < LSMBLOB_ENTRIES; i++)
+		if (blob->secid[i])
+			return blob->secid[i];
+
+	return 0;
+}
+
 /* These functions are in security/commoncap.c */
 extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
 		       int cap, unsigned int opts);
@@ -527,7 +548,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
 int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
-int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid);
+int security_secctx_to_secid(const char *secdata, u32 seclen,
+			     struct lsmblob *blob);
 void security_release_secctx(char *secdata, u32 seclen);
 void security_inode_invalidate_secctx(struct inode *inode);
 int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
@@ -1382,7 +1404,7 @@ static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *secle
 
 static inline int security_secctx_to_secid(const char *secdata,
 					   u32 seclen,
-					   u32 *secid)
+					   struct lsmblob *blob)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/kernel/cred.c b/kernel/cred.c
index ad845c99e2d1..b8e15dd371de 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -757,14 +757,12 @@ EXPORT_SYMBOL(set_security_override);
 int set_security_override_from_ctx(struct cred *new, const char *secctx)
 {
 	struct lsmblob blob;
-	u32 secid;
 	int ret;
 
-	ret = security_secctx_to_secid(secctx, strlen(secctx), &secid);
+	ret = security_secctx_to_secid(secctx, strlen(secctx), &blob);
 	if (ret < 0)
 		return ret;
 
-	lsmblob_init(&blob, secid);
 	return set_security_override(new, &blob);
 }
 EXPORT_SYMBOL(set_security_override_from_ctx);
diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
index a7e01e9952f1..f9448e81798e 100644
--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -809,21 +809,21 @@ static const struct nla_policy nft_secmark_policy[NFTA_SECMARK_MAX + 1] = {
 
 static int nft_secmark_compute_secid(struct nft_secmark *priv)
 {
-	u32 tmp_secid = 0;
+	struct lsmblob blob;
 	int err;
 
-	err = security_secctx_to_secid(priv->ctx, strlen(priv->ctx), &tmp_secid);
+	err = security_secctx_to_secid(priv->ctx, strlen(priv->ctx), &blob);
 	if (err)
 		return err;
 
-	if (!tmp_secid)
+	if (!lsmblob_is_set(&blob))
 		return -ENOENT;
 
-	err = security_secmark_relabel_packet(tmp_secid);
+	err = security_secmark_relabel_packet(lsmblob_value(&blob));
 	if (err)
 		return err;
 
-	priv->secid = tmp_secid;
+	priv->secid = lsmblob_value(&blob);
 	return 0;
 }
 
diff --git a/net/netfilter/xt_SECMARK.c b/net/netfilter/xt_SECMARK.c
index 498a0bf6f044..87ca3a537d1c 100644
--- a/net/netfilter/xt_SECMARK.c
+++ b/net/netfilter/xt_SECMARK.c
@@ -42,13 +42,14 @@ secmark_tg(struct sk_buff *skb, const struct xt_secmark_target_info_v1 *info)
 
 static int checkentry_lsm(struct xt_secmark_target_info_v1 *info)
 {
+	struct lsmblob blob;
 	int err;
 
 	info->secctx[SECMARK_SECCTX_MAX - 1] = '\0';
 	info->secid = 0;
 
 	err = security_secctx_to_secid(info->secctx, strlen(info->secctx),
-				       &info->secid);
+				       &blob);
 	if (err) {
 		if (err == -EINVAL)
 			pr_info_ratelimited("invalid security context \'%s\'\n",
@@ -56,6 +57,10 @@ static int checkentry_lsm(struct xt_secmark_target_info_v1 *info)
 		return err;
 	}
 
+	/* xt_secmark_target_info can't be changed to use lsmblobs because
+	 * it is exposed as an API. Use lsmblob_value() to get the one
+	 * value that got set by security_secctx_to_secid(). */
+	info->secid = lsmblob_value(&blob);
 	if (!info->secid) {
 		pr_info_ratelimited("unable to map security context \'%s\'\n",
 				    info->secctx);
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 3e6ac9b790b1..dd18b259272f 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -882,7 +882,7 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
 	void *addr;
 	void *mask;
 	u32 addr_len;
-	u32 secid;
+	struct lsmblob blob;
 	struct netlbl_audit audit_info;
 
 	/* Don't allow users to add both IPv4 and IPv6 addresses for a
@@ -906,13 +906,18 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
 	ret_val = security_secctx_to_secid(
 		                  nla_data(info->attrs[NLBL_UNLABEL_A_SECCTX]),
 				  nla_len(info->attrs[NLBL_UNLABEL_A_SECCTX]),
-				  &secid);
+				  &blob);
 	if (ret_val != 0)
 		return ret_val;
 
+	/* netlbl_unlhsh_add will be changed to pass a struct lsmblob *
+	 * instead of a u32 later in this patch set. security_secctx_to_secid()
+	 * will only be setting one entry in the lsmblob struct, so it is
+	 * safe to use lsmblob_value() to get that one value. */
+
 	return netlbl_unlhsh_add(&init_net,
-				 dev_name, addr, mask, addr_len, secid,
-				 &audit_info);
+				 dev_name, addr, mask, addr_len,
+				 lsmblob_value(&blob), &audit_info);
 }
 
 /**
@@ -933,7 +938,7 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
 	void *addr;
 	void *mask;
 	u32 addr_len;
-	u32 secid;
+	struct lsmblob blob;
 	struct netlbl_audit audit_info;
 
 	/* Don't allow users to add both IPv4 and IPv6 addresses for a
@@ -955,13 +960,15 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
 	ret_val = security_secctx_to_secid(
 		                  nla_data(info->attrs[NLBL_UNLABEL_A_SECCTX]),
 				  nla_len(info->attrs[NLBL_UNLABEL_A_SECCTX]),
-				  &secid);
+				  &blob);
 	if (ret_val != 0)
 		return ret_val;
 
+	/* security_secctx_to_secid() will only put one secid into the lsmblob
+	 * so it's safe to use lsmblob_value() to get the secid. */
 	return netlbl_unlhsh_add(&init_net,
-				 NULL, addr, mask, addr_len, secid,
-				 &audit_info);
+				 NULL, addr, mask, addr_len,
+				 lsmblob_value(&blob), &audit_info);
 }
 
 /**
diff --git a/security/security.c b/security/security.c
index 6a8233d746d3..cc61dd46f517 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2191,10 +2191,22 @@ int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
 }
 EXPORT_SYMBOL(security_secid_to_secctx);
 
-int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
+int security_secctx_to_secid(const char *secdata, u32 seclen,
+			     struct lsmblob *blob)
 {
-	*secid = 0;
-	return call_int_hook(secctx_to_secid, 0, secdata, seclen, secid);
+	struct security_hook_list *hp;
+	int rc;
+
+	lsmblob_init(blob, 0);
+	hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		rc = hp->hook.secctx_to_secid(secdata, seclen,
+					      &blob->secid[hp->lsmid->slot]);
+		if (rc != 0)
+			return rc;
+	}
+	return 0;
 }
 EXPORT_SYMBOL(security_secctx_to_secid);
 
@@ -2345,10 +2357,26 @@ int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
 				optval, optlen, len);
 }
 
-int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
+int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
+				     u32 *secid)
 {
-	return call_int_hook(socket_getpeersec_dgram, -ENOPROTOOPT, sock,
-			     skb, secid);
+	struct security_hook_list *hp;
+	int rc = -ENOPROTOOPT;
+
+	/*
+	 * Only one security module should provide a real hook for
+	 * this. A stub or bypass like is used in BPF should either
+	 * (somehow) leave rc unaltered or return -ENOPROTOOPT.
+	 */
+	hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_dgram,
+			     list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		rc = hp->hook.socket_getpeersec_dgram(sock, skb, secid);
+		if (rc != -ENOPROTOOPT)
+			break;
+	}
+	return rc;
 }
 EXPORT_SYMBOL(security_socket_getpeersec_dgram);
 
-- 
2.29.2

Re: [PATCH v26 07/25] LSM: Use lsmblob in security_secctx_to_secid

[Kees Cook]

On Thu, May 13, 2021 at 01:07:49PM -0700, Casey Schaufler wrote:
> Change the security_secctx_to_secid interface to use a lsmblob
> structure in place of the single u32 secid in support of
> module stacking. Change its callers to do the same.
> 
> The security module hook is unchanged, still passing back a secid.
> The infrastructure passes the correct entry from the lsmblob.
> 
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

This looks like sane refactoring into the new blob type.

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

Re: [PATCH v26 07/25] LSM: Use lsmblob in security_secctx_to_secid

[Paul Moore]

On Thu, May 13, 2021 at 4:16 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
>
> Change the security_secctx_to_secid interface to use a lsmblob
> structure in place of the single u32 secid in support of
> module stacking. Change its callers to do the same.
>
> The security module hook is unchanged, still passing back a secid.
> The infrastructure passes the correct entry from the lsmblob.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> Cc: netdev@vger.kernel.org
> Cc: netfilter-devel@vger.kernel.org
> To: Pablo Neira Ayuso <pablo@netfilter.org>
> ---
>  include/linux/security.h          | 26 ++++++++++++++++++--
>  kernel/cred.c                     |  4 +---
>  net/netfilter/nft_meta.c          | 10 ++++----
>  net/netfilter/xt_SECMARK.c        |  7 +++++-
>  net/netlabel/netlabel_unlabeled.c | 23 +++++++++++-------
>  security/security.c               | 40 ++++++++++++++++++++++++++-----
>  6 files changed, 85 insertions(+), 25 deletions(-)

Acked-by: Paul Moore <paul@paul-moore.com>


--
paul moore
www.paul-moore.com

[PATCH v26 08/25] LSM: Use lsmblob in security_secid_to_secctx

[Casey Schaufler]

Change security_secid_to_secctx() to take a lsmblob as input
instead of a u32 secid. It will then call the LSM hooks
using the lsmblob element allocated for that module. The
callers have been updated as well. This allows for the
possibility that more than one module may be called upon
to translate a secid to a string, as can occur in the
audit code.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: netdev@vger.kernel.org
Cc: linux-audit@redhat.com
Cc: netfilter-devel@vger.kernel.org
To: Pablo Neira Ayuso <pablo@netfilter.org>
To: Paul Moore <paul@paul-moore.com>
---
 drivers/android/binder.c                | 12 +++++++++-
 include/linux/security.h                |  5 +++--
 include/net/scm.h                       |  7 +++++-
 kernel/audit.c                          | 20 +++++++++++++++--
 kernel/auditsc.c                        | 28 +++++++++++++++++++----
 net/ipv4/ip_sockglue.c                  |  4 +++-
 net/netfilter/nf_conntrack_netlink.c    | 14 ++++++++++--
 net/netfilter/nf_conntrack_standalone.c |  4 +++-
 net/netfilter/nfnetlink_queue.c         | 11 +++++++--
 net/netlabel/netlabel_unlabeled.c       | 30 +++++++++++++++++++++----
 net/netlabel/netlabel_user.c            |  6 ++---
 security/security.c                     | 11 +++++----
 12 files changed, 123 insertions(+), 29 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 61d34e1dc59c..193397a1fece 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2711,6 +2711,7 @@ static void binder_transaction(struct binder_proc *proc,
 
 	if (target_node && target_node->txn_security_ctx) {
 		u32 secid;
+		struct lsmblob blob;
 		size_t added_size;
 
 		/*
@@ -2723,7 +2724,16 @@ static void binder_transaction(struct binder_proc *proc,
 		 * case well anyway.
 		 */
 		security_task_getsecid_obj(proc->tsk, &secid);
-		ret = security_secid_to_secctx(secid, &secctx, &secctx_sz);
+		/*
+		 * Later in this patch set security_task_getsecid() will
+		 * provide a lsmblob instead of a secid. lsmblob_init
+		 * is used to ensure that all the secids in the lsmblob
+		 * get the value returned from security_task_getsecid(),
+		 * which means that the one expected by
+		 * security_secid_to_secctx() will be set.
+		 */
+		lsmblob_init(&blob, secid);
+		ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz);
 		if (ret) {
 			return_error = BR_FAILED_REPLY;
 			return_error_param = ret;
diff --git a/include/linux/security.h b/include/linux/security.h
index dbb1e5f5b591..5a8c50a95c46 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -547,7 +547,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 			 size_t size);
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
-int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
+int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen);
 int security_secctx_to_secid(const char *secdata, u32 seclen,
 			     struct lsmblob *blob);
 void security_release_secctx(char *secdata, u32 seclen);
@@ -1397,7 +1397,8 @@ static inline int security_ismaclabel(const char *name)
 	return 0;
 }
 
-static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
+static inline int security_secid_to_secctx(struct lsmblob *blob,
+					   char **secdata, u32 *seclen)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/include/net/scm.h b/include/net/scm.h
index 1ce365f4c256..23a35ff1b3f2 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -92,12 +92,17 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
 #ifdef CONFIG_SECURITY_NETWORK
 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
 {
+	struct lsmblob lb;
 	char *secdata;
 	u32 seclen;
 	int err;
 
 	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
-		err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
+		/* There can only be one security module using the secid,
+		 * and the infrastructure will know which it is.
+		 */
+		lsmblob_init(&lb, scm->secid);
+		err = security_secid_to_secctx(&lb, &secdata, &seclen);
 
 		if (!err) {
 			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
diff --git a/kernel/audit.c b/kernel/audit.c
index 121d37e700a6..22286163e93e 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1442,7 +1442,16 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	case AUDIT_SIGNAL_INFO:
 		len = 0;
 		if (audit_sig_sid) {
-			err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
+			struct lsmblob blob;
+
+			/*
+			 * lsmblob_init sets all values in the lsmblob
+			 * to audit_sig_sid. This is temporary until
+			 * audit_sig_sid is converted to a lsmblob, which
+			 * happens later in this patch set.
+			 */
+			lsmblob_init(&blob, audit_sig_sid);
+			err = security_secid_to_secctx(&blob, &ctx, &len);
 			if (err)
 				return err;
 		}
@@ -2131,12 +2140,19 @@ int audit_log_task_context(struct audit_buffer *ab)
 	unsigned len;
 	int error;
 	u32 sid;
+	struct lsmblob blob;
 
 	security_task_getsecid_subj(current, &sid);
 	if (!sid)
 		return 0;
 
-	error = security_secid_to_secctx(sid, &ctx, &len);
+	/*
+	 * lsmblob_init sets all values in the lsmblob to sid.
+	 * This is temporary until security_task_getsecid is converted
+	 * to use a lsmblob, which happens later in this patch set.
+	 */
+	lsmblob_init(&blob, sid);
+	error = security_secid_to_secctx(&blob, &ctx, &len);
 	if (error) {
 		if (error != -EINVAL)
 			goto error_path;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 71d894dcdc01..6e977d312acb 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -671,6 +671,13 @@ static int audit_filter_rules(struct task_struct *tsk,
 					security_task_getsecid_subj(tsk, &sid);
 					need_sid = 0;
 				}
+				/*
+				 * lsmblob_init sets all values in the lsmblob
+				 * to sid. This is temporary until
+				 * security_task_getsecid() is converted to
+				 * provide a lsmblob, which happens later in
+				 * this patch set.
+				 */
 				lsmblob_init(&blob, sid);
 				result = security_audit_rule_match(&blob,
 							f->type, f->op,
@@ -687,6 +694,13 @@ static int audit_filter_rules(struct task_struct *tsk,
 			if (f->lsm_isset) {
 				/* Find files that match */
 				if (name) {
+					/*
+					 * lsmblob_init sets all values in the
+					 * lsmblob to sid. This is temporary
+					 * until name->osid is converted to a
+					 * lsmblob, which happens later in
+					 * this patch set.
+					 */
 					lsmblob_init(&blob, name->osid);
 					result = security_audit_rule_match(
 								&blob,
@@ -993,6 +1007,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 	char *ctx = NULL;
 	u32 len;
 	int rc = 0;
+	struct lsmblob blob;
 
 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
 	if (!ab)
@@ -1002,7 +1017,8 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
 	if (sid) {
-		if (security_secid_to_secctx(sid, &ctx, &len)) {
+		lsmblob_init(&blob, sid);
+		if (security_secid_to_secctx(&blob, &ctx, &len)) {
 			audit_log_format(ab, " obj=(none)");
 			rc = 1;
 		} else {
@@ -1245,7 +1261,10 @@ static void show_special(struct audit_context *context, int *call_panic)
 		if (osid) {
 			char *ctx = NULL;
 			u32 len;
-			if (security_secid_to_secctx(osid, &ctx, &len)) {
+			struct lsmblob blob;
+
+			lsmblob_init(&blob, osid);
+			if (security_secid_to_secctx(&blob, &ctx, &len)) {
 				audit_log_format(ab, " osid=%u", osid);
 				*call_panic = 1;
 			} else {
@@ -1398,9 +1417,10 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 	if (n->osid != 0) {
 		char *ctx = NULL;
 		u32 len;
+		struct lsmblob blob;
 
-		if (security_secid_to_secctx(
-			n->osid, &ctx, &len)) {
+		lsmblob_init(&blob, n->osid);
+		if (security_secid_to_secctx(&blob, &ctx, &len)) {
 			audit_log_format(ab, " osid=%u", n->osid);
 			if (call_panic)
 				*call_panic = 2;
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index ec6036713e2c..2f089733ada7 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -130,6 +130,7 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
 
 static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 {
+	struct lsmblob lb;
 	char *secdata;
 	u32 seclen, secid;
 	int err;
@@ -138,7 +139,8 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 	if (err)
 		return;
 
-	err = security_secid_to_secctx(secid, &secdata, &seclen);
+	lsmblob_init(&lb, secid);
+	err = security_secid_to_secctx(&lb, &secdata, &seclen);
 	if (err)
 		return;
 
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 8690fc07030f..caf3ecb5a66b 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -338,8 +338,13 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	struct nlattr *nest_secctx;
 	int len, ret;
 	char *secctx;
+	struct lsmblob blob;
 
-	ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
+	/* lsmblob_init() puts ct->secmark into all of the secids in blob.
+	 * security_secid_to_secctx() will know which security module
+	 * to use to create the secctx.  */
+	lsmblob_init(&blob, ct->secmark);
+	ret = security_secid_to_secctx(&blob, &secctx, &len);
 	if (ret)
 		return 0;
 
@@ -647,8 +652,13 @@ static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
 {
 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 	int len, ret;
+	struct lsmblob blob;
 
-	ret = security_secid_to_secctx(ct->secmark, NULL, &len);
+	/* lsmblob_init() puts ct->secmark into all of the secids in blob.
+	 * security_secid_to_secctx() will know which security module
+	 * to use to create the secctx.  */
+	lsmblob_init(&blob, ct->secmark);
+	ret = security_secid_to_secctx(&blob, NULL, &len);
 	if (ret)
 		return 0;
 
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index aaa55246d0ca..b02afa0a1516 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -175,8 +175,10 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 	int ret;
 	u32 len;
 	char *secctx;
+	struct lsmblob blob;
 
-	ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
+	lsmblob_init(&blob, ct->secmark);
+	ret = security_secid_to_secctx(&blob, &secctx, &len);
 	if (ret)
 		return;
 
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index f37a575ebd7f..bdbb0b60bf7b 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -305,13 +305,20 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
 {
 	u32 seclen = 0;
 #if IS_ENABLED(CONFIG_NETWORK_SECMARK)
+	struct lsmblob blob;
+
 	if (!skb || !sk_fullsock(skb->sk))
 		return 0;
 
 	read_lock_bh(&skb->sk->sk_callback_lock);
 
-	if (skb->secmark)
-		security_secid_to_secctx(skb->secmark, secdata, &seclen);
+	if (skb->secmark) {
+		/* lsmblob_init() puts ct->secmark into all of the secids in
+		 * blob. security_secid_to_secctx() will know which security
+		 * module to use to create the secctx.  */
+		lsmblob_init(&blob, skb->secmark);
+		security_secid_to_secctx(&blob, secdata, &seclen);
+	}
 
 	read_unlock_bh(&skb->sk->sk_callback_lock);
 #endif
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index dd18b259272f..534dee9c7b6f 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -376,6 +376,7 @@ int netlbl_unlhsh_add(struct net *net,
 	struct audit_buffer *audit_buf = NULL;
 	char *secctx = NULL;
 	u32 secctx_len;
+	struct lsmblob blob;
 
 	if (addr_len != sizeof(struct in_addr) &&
 	    addr_len != sizeof(struct in6_addr))
@@ -438,7 +439,11 @@ int netlbl_unlhsh_add(struct net *net,
 unlhsh_add_return:
 	rcu_read_unlock();
 	if (audit_buf != NULL) {
-		if (security_secid_to_secctx(secid,
+		/* lsmblob_init() puts secid into all of the secids in blob.
+		 * security_secid_to_secctx() will know which security module
+		 * to use to create the secctx.  */
+		lsmblob_init(&blob, secid);
+		if (security_secid_to_secctx(&blob,
 					     &secctx,
 					     &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
@@ -475,6 +480,7 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 	struct net_device *dev;
 	char *secctx;
 	u32 secctx_len;
+	struct lsmblob blob;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	list_entry = netlbl_af4list_remove(addr->s_addr, mask->s_addr,
@@ -494,8 +500,13 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 					  addr->s_addr, mask->s_addr);
 		if (dev != NULL)
 			dev_put(dev);
+		/* lsmblob_init() puts entry->secid into all of the secids
+		 * in blob. security_secid_to_secctx() will know which
+		 * security module to use to create the secctx.  */
+		if (entry != NULL)
+			lsmblob_init(&blob, entry->secid);
 		if (entry != NULL &&
-		    security_secid_to_secctx(entry->secid,
+		    security_secid_to_secctx(&blob,
 					     &secctx, &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
 			security_release_secctx(secctx, secctx_len);
@@ -537,6 +548,7 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 	struct net_device *dev;
 	char *secctx;
 	u32 secctx_len;
+	struct lsmblob blob;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	list_entry = netlbl_af6list_remove(addr, mask, &iface->addr6_list);
@@ -555,8 +567,13 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 					  addr, mask);
 		if (dev != NULL)
 			dev_put(dev);
+		/* lsmblob_init() puts entry->secid into all of the secids
+		 * in blob. security_secid_to_secctx() will know which
+		 * security module to use to create the secctx.  */
+		if (entry != NULL)
+			lsmblob_init(&blob, entry->secid);
 		if (entry != NULL &&
-		    security_secid_to_secctx(entry->secid,
+		    security_secid_to_secctx(&blob,
 					     &secctx, &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
 			security_release_secctx(secctx, secctx_len);
@@ -1082,6 +1099,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 	u32 secid;
 	char *secctx;
 	u32 secctx_len;
+	struct lsmblob blob;
 
 	data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).portid,
 			   cb_arg->seq, &netlbl_unlabel_gnl_family,
@@ -1136,7 +1154,11 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 		secid = addr6->secid;
 	}
 
-	ret_val = security_secid_to_secctx(secid, &secctx, &secctx_len);
+	/* lsmblob_init() secid into all of the secids in blob.
+	 * security_secid_to_secctx() will know which security module
+	 * to use to create the secctx.  */
+	lsmblob_init(&blob, secid);
+	ret_val = security_secid_to_secctx(&blob, &secctx, &secctx_len);
 	if (ret_val != 0)
 		goto list_cb_failure;
 	ret_val = nla_put(cb_arg->skb,
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 3ed4fea2a2de..893301ae0131 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -86,6 +86,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 	struct audit_buffer *audit_buf;
 	char *secctx;
 	u32 secctx_len;
+	struct lsmblob blob;
 
 	if (audit_enabled == AUDIT_OFF)
 		return NULL;
@@ -98,10 +99,9 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 			 from_kuid(&init_user_ns, audit_info->loginuid),
 			 audit_info->sessionid);
 
+	lsmblob_init(&blob, audit_info->secid);
 	if (audit_info->secid != 0 &&
-	    security_secid_to_secctx(audit_info->secid,
-				     &secctx,
-				     &secctx_len) == 0) {
+	    security_secid_to_secctx(&blob, &secctx, &secctx_len) == 0) {
 		audit_log_format(audit_buf, " subj=%s", secctx);
 		security_release_secctx(secctx, secctx_len);
 	}
diff --git a/security/security.c b/security/security.c
index cc61dd46f517..67140d6c17a2 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2172,17 +2172,16 @@ int security_ismaclabel(const char *name)
 }
 EXPORT_SYMBOL(security_ismaclabel);
 
-int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
+int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen)
 {
 	struct security_hook_list *hp;
 	int rc;
 
-	/*
-	 * Currently, only one LSM can implement secid_to_secctx (i.e this
-	 * LSM hook is not "stackable").
-	 */
 	hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
-		rc = hp->hook.secid_to_secctx(secid, secdata, seclen);
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		rc = hp->hook.secid_to_secctx(blob->secid[hp->lsmid->slot],
+					      secdata, seclen);
 		if (rc != LSM_RET_DEFAULT(secid_to_secctx))
 			return rc;
 	}
-- 
2.29.2

Re: [PATCH v26 08/25] LSM: Use lsmblob in security_secid_to_secctx

[Kees Cook]

On Thu, May 13, 2021 at 01:07:50PM -0700, Casey Schaufler wrote:
> Change security_secid_to_secctx() to take a lsmblob as input
> instead of a u32 secid. It will then call the LSM hooks
> using the lsmblob element allocated for that module. The
> callers have been updated as well. This allows for the
> possibility that more than one module may be called upon
> to translate a secid to a string, as can occur in the
> audit code.
> 
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

This looks sensible.

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

Re: [PATCH v26 08/25] LSM: Use lsmblob in security_secid_to_secctx

[Paul Moore]

On Thu, May 13, 2021 at 4:17 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
>
> Change security_secid_to_secctx() to take a lsmblob as input
> instead of a u32 secid. It will then call the LSM hooks
> using the lsmblob element allocated for that module. The
> callers have been updated as well. This allows for the
> possibility that more than one module may be called upon
> to translate a secid to a string, as can occur in the
> audit code.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> Cc: netdev@vger.kernel.org
> Cc: linux-audit@redhat.com
> Cc: netfilter-devel@vger.kernel.org
> To: Pablo Neira Ayuso <pablo@netfilter.org>
> To: Paul Moore <paul@paul-moore.com>
> ---
>  drivers/android/binder.c                | 12 +++++++++-
>  include/linux/security.h                |  5 +++--
>  include/net/scm.h                       |  7 +++++-
>  kernel/audit.c                          | 20 +++++++++++++++--
>  kernel/auditsc.c                        | 28 +++++++++++++++++++----
>  net/ipv4/ip_sockglue.c                  |  4 +++-
>  net/netfilter/nf_conntrack_netlink.c    | 14 ++++++++++--
>  net/netfilter/nf_conntrack_standalone.c |  4 +++-
>  net/netfilter/nfnetlink_queue.c         | 11 +++++++--
>  net/netlabel/netlabel_unlabeled.c       | 30 +++++++++++++++++++++----
>  net/netlabel/netlabel_user.c            |  6 ++---
>  security/security.c                     | 11 +++++----
>  12 files changed, 123 insertions(+), 29 deletions(-)

Acked-by: Paul Moore <paul@paul-moore.com>


--
paul moore
www.paul-moore.com

[PATCH v26 09/25] LSM: Use lsmblob in security_ipc_getsecid

[Casey Schaufler]

There may be more than one LSM that provides IPC data
for auditing. Change security_ipc_getsecid() to fill in
a lsmblob structure instead of the u32 secid. The
audit data structure containing the secid will be updated
later, so there is a bit of scaffolding here.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-audit@redhat.com
---
 include/linux/security.h |  7 ++++---
 kernel/auditsc.c         |  7 ++++++-
 security/security.c      | 12 +++++++++---
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index 5a8c50a95c46..bdac0a124052 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -518,7 +518,7 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 			unsigned long arg4, unsigned long arg5);
 void security_task_to_inode(struct task_struct *p, struct inode *inode);
 int security_ipc_permission(struct kern_ipc_perm *ipcp, short flag);
-void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid);
+void security_ipc_getsecid(struct kern_ipc_perm *ipcp, struct lsmblob *blob);
 int security_msg_msg_alloc(struct msg_msg *msg);
 void security_msg_msg_free(struct msg_msg *msg);
 int security_msg_queue_alloc(struct kern_ipc_perm *msq);
@@ -1275,9 +1275,10 @@ static inline int security_ipc_permission(struct kern_ipc_perm *ipcp,
 	return 0;
 }
 
-static inline void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
+static inline void security_ipc_getsecid(struct kern_ipc_perm *ipcp,
+					 struct lsmblob *blob)
 {
-	*secid = 0;
+	lsmblob_init(blob, 0);
 }
 
 static inline int security_msg_msg_alloc(struct msg_msg *msg)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 6e977d312acb..9aeddf881e67 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2323,11 +2323,16 @@ void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
 void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
 {
 	struct audit_context *context = audit_context();
+	struct lsmblob blob;
 	context->ipc.uid = ipcp->uid;
 	context->ipc.gid = ipcp->gid;
 	context->ipc.mode = ipcp->mode;
 	context->ipc.has_perm = 0;
-	security_ipc_getsecid(ipcp, &context->ipc.osid);
+	security_ipc_getsecid(ipcp, &blob);
+	/* context->ipc.osid will be changed to a lsmblob later in
+	 * the patch series. This will allow auditing of all the object
+	 * labels associated with the ipc object. */
+	context->ipc.osid = lsmblob_value(&blob);
 	context->type = AUDIT_IPC;
 }
 
diff --git a/security/security.c b/security/security.c
index 67140d6c17a2..0364531d92cf 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1992,10 +1992,16 @@ int security_ipc_permission(struct kern_ipc_perm *ipcp, short flag)
 	return call_int_hook(ipc_permission, 0, ipcp, flag);
 }
 
-void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
+void security_ipc_getsecid(struct kern_ipc_perm *ipcp, struct lsmblob *blob)
 {
-	*secid = 0;
-	call_void_hook(ipc_getsecid, ipcp, secid);
+	struct security_hook_list *hp;
+
+	lsmblob_init(blob, 0);
+	hlist_for_each_entry(hp, &security_hook_heads.ipc_getsecid, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		hp->hook.ipc_getsecid(ipcp, &blob->secid[hp->lsmid->slot]);
+	}
 }
 
 int security_msg_msg_alloc(struct msg_msg *msg)
-- 
2.29.2

[PATCH v26 10/25] LSM: Use lsmblob in security_task_getsecid

[Casey Schaufler]

Change the security_task_getsecid_subj() and
security_task_getsecid_obj() interfaces to fill in
a lsmblob structure instead of a u32 secid in support of
LSM stacking. Audit interfaces will need to collect all
possible secids for possible reporting.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-integrity@vger.kernel.org
Cc: linux-audit@redhat.com
Cc: netdev@vger.kernel.org
---
 drivers/android/binder.c              | 12 +-----
 include/linux/security.h              | 14 ++++---
 kernel/audit.c                        | 16 +++-----
 kernel/auditfilter.c                  |  4 +-
 kernel/auditsc.c                      | 25 ++++++------
 net/netlabel/netlabel_unlabeled.c     |  5 ++-
 net/netlabel/netlabel_user.h          |  6 ++-
 security/integrity/ima/ima_appraise.c | 10 +++--
 security/integrity/ima/ima_main.c     | 56 +++++++++++++++------------
 security/security.c                   | 25 +++++++++---
 10 files changed, 94 insertions(+), 79 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 193397a1fece..ab55358f868b 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2710,7 +2710,6 @@ static void binder_transaction(struct binder_proc *proc,
 	t->priority = task_nice(current);
 
 	if (target_node && target_node->txn_security_ctx) {
-		u32 secid;
 		struct lsmblob blob;
 		size_t added_size;
 
@@ -2723,16 +2722,7 @@ static void binder_transaction(struct binder_proc *proc,
 		 * here; however, it isn't clear that binder would handle that
 		 * case well anyway.
 		 */
-		security_task_getsecid_obj(proc->tsk, &secid);
-		/*
-		 * Later in this patch set security_task_getsecid() will
-		 * provide a lsmblob instead of a secid. lsmblob_init
-		 * is used to ensure that all the secids in the lsmblob
-		 * get the value returned from security_task_getsecid(),
-		 * which means that the one expected by
-		 * security_secid_to_secctx() will be set.
-		 */
-		lsmblob_init(&blob, secid);
+		security_task_getsecid_obj(proc->tsk, &blob);
 		ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz);
 		if (ret) {
 			return_error = BR_FAILED_REPLY;
diff --git a/include/linux/security.h b/include/linux/security.h
index bdac0a124052..60f4515b9181 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -500,8 +500,8 @@ int security_task_fix_setgid(struct cred *new, const struct cred *old,
 int security_task_setpgid(struct task_struct *p, pid_t pgid);
 int security_task_getpgid(struct task_struct *p);
 int security_task_getsid(struct task_struct *p);
-void security_task_getsecid_subj(struct task_struct *p, u32 *secid);
-void security_task_getsecid_obj(struct task_struct *p, u32 *secid);
+void security_task_getsecid_subj(struct task_struct *p, struct lsmblob *blob);
+void security_task_getsecid_obj(struct task_struct *p, struct lsmblob *blob);
 int security_task_setnice(struct task_struct *p, int nice);
 int security_task_setioprio(struct task_struct *p, int ioprio);
 int security_task_getioprio(struct task_struct *p);
@@ -1197,14 +1197,16 @@ static inline int security_task_getsid(struct task_struct *p)
 	return 0;
 }
 
-static inline void security_task_getsecid_subj(struct task_struct *p, u32 *secid)
+static inline void security_task_getsecid_subj(struct task_struct *p,
+					       struct lsmblob *blob)
 {
-	*secid = 0;
+	lsmblob_init(blob, 0);
 }
 
-static inline void security_task_getsecid_obj(struct task_struct *p, u32 *secid)
+static inline void security_task_getsecid_obj(struct task_struct *p,
+					      struct lsmblob *blob)
 {
-	*secid = 0;
+	lsmblob_init(blob, 0);
 }
 
 static inline int security_task_setnice(struct task_struct *p, int nice)
diff --git a/kernel/audit.c b/kernel/audit.c
index 22286163e93e..d92c7b894183 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -2139,19 +2139,12 @@ int audit_log_task_context(struct audit_buffer *ab)
 	char *ctx = NULL;
 	unsigned len;
 	int error;
-	u32 sid;
 	struct lsmblob blob;
 
-	security_task_getsecid_subj(current, &sid);
-	if (!sid)
+	security_task_getsecid_subj(current, &blob);
+	if (!lsmblob_is_set(&blob))
 		return 0;
 
-	/*
-	 * lsmblob_init sets all values in the lsmblob to sid.
-	 * This is temporary until security_task_getsecid is converted
-	 * to use a lsmblob, which happens later in this patch set.
-	 */
-	lsmblob_init(&blob, sid);
 	error = security_secid_to_secctx(&blob, &ctx, &len);
 	if (error) {
 		if (error != -EINVAL)
@@ -2359,6 +2352,7 @@ int audit_set_loginuid(kuid_t loginuid)
 int audit_signal_info(int sig, struct task_struct *t)
 {
 	kuid_t uid = current_uid(), auid;
+	struct lsmblob blob;
 
 	if (auditd_test_task(t) &&
 	    (sig == SIGTERM || sig == SIGHUP ||
@@ -2369,7 +2363,9 @@ int audit_signal_info(int sig, struct task_struct *t)
 			audit_sig_uid = auid;
 		else
 			audit_sig_uid = uid;
-		security_task_getsecid_subj(current, &audit_sig_sid);
+		security_task_getsecid_subj(current, &blob);
+		/* scaffolding until audit_sig_sid is converted */
+		audit_sig_sid = blob.secid[0];
 	}
 
 	return audit_signal_info_syscall(t);
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 6a04d762d272..1ba14a7a38f7 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1330,7 +1330,6 @@ int audit_filter(int msgtype, unsigned int listtype)
 		for (i = 0; i < e->rule.field_count; i++) {
 			struct audit_field *f = &e->rule.fields[i];
 			pid_t pid;
-			u32 sid;
 			struct lsmblob blob;
 
 			switch (f->type) {
@@ -1362,8 +1361,7 @@ int audit_filter(int msgtype, unsigned int listtype)
 			case AUDIT_SUBJ_CLR:
 				if (f->lsm_isset) {
 					security_task_getsecid_subj(current,
-								    &sid);
-					lsmblob_init(&blob, sid);
+								    &blob);
 					result = security_audit_rule_match(
 						   &blob, f->type, f->op,
 						   f->lsm_rules);
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 9aeddf881e67..dd902b68433e 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -471,7 +471,6 @@ static int audit_filter_rules(struct task_struct *tsk,
 {
 	const struct cred *cred;
 	int i, need_sid = 1;
-	u32 sid;
 	struct lsmblob blob;
 	unsigned int sessionid;
 
@@ -668,17 +667,9 @@ static int audit_filter_rules(struct task_struct *tsk,
 			   logged upon error */
 			if (f->lsm_isset) {
 				if (need_sid) {
-					security_task_getsecid_subj(tsk, &sid);
+					security_task_getsecid_subj(tsk, &blob);
 					need_sid = 0;
 				}
-				/*
-				 * lsmblob_init sets all values in the lsmblob
-				 * to sid. This is temporary until
-				 * security_task_getsecid() is converted to
-				 * provide a lsmblob, which happens later in
-				 * this patch set.
-				 */
-				lsmblob_init(&blob, sid);
 				result = security_audit_rule_match(&blob,
 							f->type, f->op,
 							f->lsm_rules);
@@ -2422,12 +2413,15 @@ int __audit_sockaddr(int len, void *a)
 void __audit_ptrace(struct task_struct *t)
 {
 	struct audit_context *context = audit_context();
+	struct lsmblob blob;
 
 	context->target_pid = task_tgid_nr(t);
 	context->target_auid = audit_get_loginuid(t);
 	context->target_uid = task_uid(t);
 	context->target_sessionid = audit_get_sessionid(t);
-	security_task_getsecid_obj(t, &context->target_sid);
+	security_task_getsecid_obj(t, &blob);
+	/* scaffolding - until target_sid is converted */
+	context->target_sid = blob.secid[0];
 	memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
 }
 
@@ -2443,6 +2437,7 @@ int audit_signal_info_syscall(struct task_struct *t)
 	struct audit_aux_data_pids *axp;
 	struct audit_context *ctx = audit_context();
 	kuid_t t_uid = task_uid(t);
+	struct lsmblob blob;
 
 	if (!audit_signals || audit_dummy_context())
 		return 0;
@@ -2454,7 +2449,9 @@ int audit_signal_info_syscall(struct task_struct *t)
 		ctx->target_auid = audit_get_loginuid(t);
 		ctx->target_uid = t_uid;
 		ctx->target_sessionid = audit_get_sessionid(t);
-		security_task_getsecid_obj(t, &ctx->target_sid);
+		security_task_getsecid_obj(t, &blob);
+		/* scaffolding until target_sid is converted */
+		ctx->target_sid = blob.secid[0];
 		memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
 		return 0;
 	}
@@ -2475,7 +2472,9 @@ int audit_signal_info_syscall(struct task_struct *t)
 	axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
 	axp->target_uid[axp->pid_count] = t_uid;
 	axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
-	security_task_getsecid_obj(t, &axp->target_sid[axp->pid_count]);
+	security_task_getsecid_obj(t, &blob);
+	/* scaffolding until target_sid is converted */
+	axp->target_sid[axp->pid_count] = blob.secid[0];
 	memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);
 	axp->pid_count++;
 
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 534dee9c7b6f..b08442582874 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -1564,11 +1564,14 @@ int __init netlbl_unlabel_defconf(void)
 	int ret_val;
 	struct netlbl_dom_map *entry;
 	struct netlbl_audit audit_info;
+	struct lsmblob blob;
 
 	/* Only the kernel is allowed to call this function and the only time
 	 * it is called is at bootup before the audit subsystem is reporting
 	 * messages so don't worry to much about these values. */
-	security_task_getsecid_subj(current, &audit_info.secid);
+	security_task_getsecid_subj(current, &blob);
+	/* scaffolding until audit_info.secid is converted */
+	audit_info.secid = blob.secid[0];
 	audit_info.loginuid = GLOBAL_ROOT_UID;
 	audit_info.sessionid = 0;
 
diff --git a/net/netlabel/netlabel_user.h b/net/netlabel/netlabel_user.h
index b9ba8112b3c5..11f6da93f31b 100644
--- a/net/netlabel/netlabel_user.h
+++ b/net/netlabel/netlabel_user.h
@@ -34,7 +34,11 @@
 static inline void netlbl_netlink_auditinfo(struct sk_buff *skb,
 					    struct netlbl_audit *audit_info)
 {
-	security_task_getsecid_subj(current, &audit_info->secid);
+	struct lsmblob blob;
+
+	security_task_getsecid_subj(current, &blob);
+	/* scaffolding until secid is converted */
+	audit_info->secid = blob.secid[0];
 	audit_info->loginuid = audit_get_loginuid(current);
 	audit_info->sessionid = audit_get_sessionid(current);
 }
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 4e5eb0236278..f8c7b593175f 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -71,14 +71,16 @@ bool is_ima_appraise_enabled(void)
 int ima_must_appraise(struct user_namespace *mnt_userns, struct inode *inode,
 		      int mask, enum ima_hooks func)
 {
-	u32 secid;
+	struct lsmblob blob;
 
 	if (!ima_appraise)
 		return 0;
 
-	security_task_getsecid_subj(current, &secid);
-	return ima_match_policy(mnt_userns, inode, current_cred(), secid, func,
-				mask, IMA_APPRAISE | IMA_HASH, NULL, NULL, NULL);
+	security_task_getsecid_subj(current, &blob);
+	/* scaffolding the .secid[0] */
+	return ima_match_policy(mnt_userns, inode, current_cred(),
+				blob.secid[0], func, mask,
+				IMA_APPRAISE | IMA_HASH, NULL, NULL, NULL);
 }
 
 static int ima_fix_xattr(struct dentry *dentry,
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 906c1d8e0b71..9d1ed00eb349 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -388,12 +388,13 @@ static int process_measurement(struct file *file, const struct cred *cred,
  */
 int ima_file_mmap(struct file *file, unsigned long prot)
 {
-	u32 secid;
+	struct lsmblob blob;
 
 	if (file && (prot & PROT_EXEC)) {
-		security_task_getsecid_subj(current, &secid);
-		return process_measurement(file, current_cred(), secid, NULL,
-					   0, MAY_EXEC, MMAP_CHECK);
+		security_task_getsecid_subj(current, &blob);
+		/* scaffolding - until process_measurement changes */
+		return process_measurement(file, current_cred(), blob.secid[0],
+					   NULL, 0, MAY_EXEC, MMAP_CHECK);
 	}
 
 	return 0;
@@ -419,9 +420,9 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 	char *pathbuf = NULL;
 	const char *pathname = NULL;
 	struct inode *inode;
+	struct lsmblob blob;
 	int result = 0;
 	int action;
-	u32 secid;
 	int pcr;
 
 	/* Is mprotect making an mmap'ed file executable? */
@@ -429,11 +430,12 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 	    !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC))
 		return 0;
 
-	security_task_getsecid_subj(current, &secid);
+	security_task_getsecid_subj(current, &blob);
 	inode = file_inode(vma->vm_file);
+	/* scaffolding */
 	action = ima_get_action(file_mnt_user_ns(vma->vm_file), inode,
-				current_cred(), secid, MAY_EXEC, MMAP_CHECK,
-				&pcr, &template, 0);
+				current_cred(), blob.secid[0], MAY_EXEC,
+				MMAP_CHECK, &pcr, &template, 0);
 
 	/* Is the mmap'ed file in policy? */
 	if (!(action & (IMA_MEASURE | IMA_APPRAISE_SUBMASK)))
@@ -469,10 +471,12 @@ int ima_bprm_check(struct linux_binprm *bprm)
 {
 	int ret;
 	u32 secid;
+	struct lsmblob blob;
 
-	security_task_getsecid_subj(current, &secid);
-	ret = process_measurement(bprm->file, current_cred(), secid, NULL, 0,
-				  MAY_EXEC, BPRM_CHECK);
+	security_task_getsecid_subj(current, &blob);
+	/* scaffolding until process_measurement changes */
+	ret = process_measurement(bprm->file, current_cred(), blob.secid[0],
+				  NULL, 0, MAY_EXEC, BPRM_CHECK);
 	if (ret)
 		return ret;
 
@@ -493,10 +497,11 @@ int ima_bprm_check(struct linux_binprm *bprm)
  */
 int ima_file_check(struct file *file, int mask)
 {
-	u32 secid;
+	struct lsmblob blob;
 
-	security_task_getsecid_subj(current, &secid);
-	return process_measurement(file, current_cred(), secid, NULL, 0,
+	security_task_getsecid_subj(current, &blob);
+	/* scaffolding until process_measurement changes */
+	return process_measurement(file, current_cred(), blob.secid[0], NULL, 0,
 				   mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
 					   MAY_APPEND), FILE_CHECK);
 }
@@ -672,7 +677,7 @@ int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
 		  bool contents)
 {
 	enum ima_hooks func;
-	u32 secid;
+	struct lsmblob blob;
 
 	/*
 	 * Do devices using pre-allocated memory run the risk of the
@@ -692,8 +697,9 @@ int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
 
 	/* Read entire file for all partial reads. */
 	func = read_idmap[read_id] ?: FILE_CHECK;
-	security_task_getsecid_subj(current, &secid);
-	return process_measurement(file, current_cred(), secid, NULL,
+	security_task_getsecid_subj(current, &blob);
+	/* scaffolding - until process_measurement changes */
+	return process_measurement(file, current_cred(), blob.secid[0], NULL,
 				   0, MAY_READ, func);
 }
 
@@ -722,7 +728,7 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
 		       enum kernel_read_file_id read_id)
 {
 	enum ima_hooks func;
-	u32 secid;
+	struct lsmblob blob;
 
 	/* permit signed certs */
 	if (!file && read_id == READING_X509_CERTIFICATE)
@@ -735,9 +741,10 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
 	}
 
 	func = read_idmap[read_id] ?: FILE_CHECK;
-	security_task_getsecid_subj(current, &secid);
-	return process_measurement(file, current_cred(), secid, buf, size,
-				   MAY_READ, func);
+	security_task_getsecid_subj(current, &blob);
+	/* scaffolding until process_measurement changes */
+	return process_measurement(file, current_cred(), blob.secid[0], buf,
+				   size, MAY_READ, func);
 }
 
 /**
@@ -859,7 +866,7 @@ void process_buffer_measurement(struct user_namespace *mnt_userns,
 	int digest_hash_len = hash_digest_size[ima_hash_algo];
 	int violation = 0;
 	int action = 0;
-	u32 secid;
+	struct lsmblob blob;
 
 	if (!ima_policy_flag)
 		return;
@@ -879,9 +886,10 @@ void process_buffer_measurement(struct user_namespace *mnt_userns,
 	 * buffer measurements.
 	 */
 	if (func) {
-		security_task_getsecid_subj(current, &secid);
+		security_task_getsecid_subj(current, &blob);
+		/* scaffolding */
 		action = ima_get_action(mnt_userns, inode, current_cred(),
-					secid, 0, func, &pcr, &template,
+					blob.secid[0], 0, func, &pcr, &template,
 					func_data);
 		if (!(action & IMA_MEASURE))
 			return;
diff --git a/security/security.c b/security/security.c
index 0364531d92cf..f3b985f76dab 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1902,17 +1902,30 @@ int security_task_getsid(struct task_struct *p)
 	return call_int_hook(task_getsid, 0, p);
 }
 
-void security_task_getsecid_subj(struct task_struct *p, u32 *secid)
+void security_task_getsecid_subj(struct task_struct *p, struct lsmblob *blob)
 {
-	*secid = 0;
-	call_void_hook(task_getsecid_subj, p, secid);
+	struct security_hook_list *hp;
+
+	lsmblob_init(blob, 0);
+	hlist_for_each_entry(hp, &security_hook_heads.task_getsecid_subj,
+			     list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		hp->hook.task_getsecid_subj(p, &blob->secid[hp->lsmid->slot]);
+	}
 }
 EXPORT_SYMBOL(security_task_getsecid_subj);
 
-void security_task_getsecid_obj(struct task_struct *p, u32 *secid)
+void security_task_getsecid_obj(struct task_struct *p, struct lsmblob *blob)
 {
-	*secid = 0;
-	call_void_hook(task_getsecid_obj, p, secid);
+	struct security_hook_list *hp;
+
+	lsmblob_init(blob, 0);
+	hlist_for_each_entry(hp, &security_hook_heads.task_getsecid_obj, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		hp->hook.task_getsecid_obj(p, &blob->secid[hp->lsmid->slot]);
+	}
 }
 EXPORT_SYMBOL(security_task_getsecid_obj);
 
-- 
2.29.2

[PATCH v26 11/25] LSM: Use lsmblob in security_inode_getsecid

[Casey Schaufler]

Change the security_inode_getsecid() interface to fill in a
lsmblob structure instead of a u32 secid. This allows for its
callers to gather data from all registered LSMs. Data is provided
for IMA and audit.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-integrity@vger.kernel.org
Cc: linux-audit@redhat.com
---
 include/linux/security.h            |  7 ++++---
 kernel/auditsc.c                    |  6 +++++-
 security/integrity/ima/ima_policy.c |  4 +---
 security/security.c                 | 11 +++++++++--
 4 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index 60f4515b9181..64f898e5e854 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -454,7 +454,7 @@ int security_inode_getsecurity(struct user_namespace *mnt_userns,
 			       void **buffer, bool alloc);
 int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags);
 int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size);
-void security_inode_getsecid(struct inode *inode, u32 *secid);
+void security_inode_getsecid(struct inode *inode, struct lsmblob *blob);
 int security_inode_copy_up(struct dentry *src, struct cred **new);
 int security_inode_copy_up_xattr(const char *name);
 int security_kernfs_init_security(struct kernfs_node *kn_dir,
@@ -1005,9 +1005,10 @@ static inline int security_inode_listsecurity(struct inode *inode, char *buffer,
 	return 0;
 }
 
-static inline void security_inode_getsecid(struct inode *inode, u32 *secid)
+static inline void security_inode_getsecid(struct inode *inode,
+					   struct lsmblob *blob)
 {
-	*secid = 0;
+	lsmblob_init(blob, 0);
 }
 
 static inline int security_inode_copy_up(struct dentry *src, struct cred **new)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index dd902b68433e..6684927f12fc 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1962,13 +1962,17 @@ static void audit_copy_inode(struct audit_names *name,
 			     const struct dentry *dentry,
 			     struct inode *inode, unsigned int flags)
 {
+	struct lsmblob blob;
+
 	name->ino   = inode->i_ino;
 	name->dev   = inode->i_sb->s_dev;
 	name->mode  = inode->i_mode;
 	name->uid   = inode->i_uid;
 	name->gid   = inode->i_gid;
 	name->rdev  = inode->i_rdev;
-	security_inode_getsecid(inode, &name->osid);
+	security_inode_getsecid(inode, &blob);
+	/* scaffolding until osid is updated */
+	name->osid = blob.secid[0];
 	if (flags & AUDIT_INODE_NOEVAL) {
 		name->fcap_ver = -1;
 		return;
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index a05841e1012b..5ee7629fd782 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -606,7 +606,6 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
 		return false;
 	for (i = 0; i < MAX_LSM_RULES; i++) {
 		int rc = 0;
-		u32 osid;
 		struct lsmblob lsmdata;
 
 		if (!ima_lsm_isset(rule, i)) {
@@ -619,8 +618,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
 		case LSM_OBJ_USER:
 		case LSM_OBJ_ROLE:
 		case LSM_OBJ_TYPE:
-			security_inode_getsecid(inode, &osid);
-			lsmblob_init(&lsmdata, osid);
+			security_inode_getsecid(inode, &lsmdata);
 			rc = ima_filter_rule_match(&lsmdata, rule->lsm[i].type,
 						   Audit_equal,
 						   rule->lsm[i].rule);
diff --git a/security/security.c b/security/security.c
index f3b985f76dab..54f4a4ead69f 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1546,9 +1546,16 @@ int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer
 }
 EXPORT_SYMBOL(security_inode_listsecurity);
 
-void security_inode_getsecid(struct inode *inode, u32 *secid)
+void security_inode_getsecid(struct inode *inode, struct lsmblob *blob)
 {
-	call_void_hook(inode_getsecid, inode, secid);
+	struct security_hook_list *hp;
+
+	lsmblob_init(blob, 0);
+	hlist_for_each_entry(hp, &security_hook_heads.inode_getsecid, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		hp->hook.inode_getsecid(inode, &blob->secid[hp->lsmid->slot]);
+	}
 }
 
 int security_inode_copy_up(struct dentry *src, struct cred **new)
-- 
2.29.2

[PATCH v26 12/25] LSM: Use lsmblob in security_cred_getsecid

[Casey Schaufler]

Change the security_cred_getsecid() interface to fill in a
lsmblob instead of a u32 secid. The associated data elements
in the audit sub-system are changed from a secid to a lsmblob
to accommodate multiple possible LSM audit users.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-integrity@vger.kernel.org
Cc: linux-audit@redhat.com
---
 include/linux/security.h          |  2 +-
 kernel/audit.c                    | 25 +++++++----------------
 kernel/audit.h                    |  3 ++-
 kernel/auditsc.c                  | 34 ++++++++++++-------------------
 security/integrity/ima/ima_main.c |  8 ++++----
 security/security.c               | 12 ++++++++---
 6 files changed, 36 insertions(+), 48 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index 64f898e5e854..c1c31eb23859 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -481,7 +481,7 @@ int security_cred_alloc_blank(struct cred *cred, gfp_t gfp);
 void security_cred_free(struct cred *cred);
 int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp);
 void security_transfer_creds(struct cred *new, const struct cred *old);
-void security_cred_getsecid(const struct cred *c, u32 *secid);
+void security_cred_getsecid(const struct cred *c, struct lsmblob *blob);
 int security_kernel_act_as(struct cred *new, struct lsmblob *blob);
 int security_kernel_create_files_as(struct cred *new, struct inode *inode);
 int security_kernel_module_request(char *kmod_name);
diff --git a/kernel/audit.c b/kernel/audit.c
index d92c7b894183..8ec64e6e8bc0 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -125,7 +125,7 @@ static u32	audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
 /* The identity of the user shutting down the audit system. */
 static kuid_t		audit_sig_uid = INVALID_UID;
 static pid_t		audit_sig_pid = -1;
-static u32		audit_sig_sid;
+struct lsmblob		audit_sig_lsm;
 
 /* Records can be lost in several ways:
    0) [suppressed in audit_alloc]
@@ -1441,29 +1441,21 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	}
 	case AUDIT_SIGNAL_INFO:
 		len = 0;
-		if (audit_sig_sid) {
-			struct lsmblob blob;
-
-			/*
-			 * lsmblob_init sets all values in the lsmblob
-			 * to audit_sig_sid. This is temporary until
-			 * audit_sig_sid is converted to a lsmblob, which
-			 * happens later in this patch set.
-			 */
-			lsmblob_init(&blob, audit_sig_sid);
-			err = security_secid_to_secctx(&blob, &ctx, &len);
+		if (lsmblob_is_set(&audit_sig_lsm)) {
+			err = security_secid_to_secctx(&audit_sig_lsm, &ctx,
+						       &len);
 			if (err)
 				return err;
 		}
 		sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
 		if (!sig_data) {
-			if (audit_sig_sid)
+			if (lsmblob_is_set(&audit_sig_lsm))
 				security_release_secctx(ctx, len);
 			return -ENOMEM;
 		}
 		sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
 		sig_data->pid = audit_sig_pid;
-		if (audit_sig_sid) {
+		if (lsmblob_is_set(&audit_sig_lsm)) {
 			memcpy(sig_data->ctx, ctx, len);
 			security_release_secctx(ctx, len);
 		}
@@ -2352,7 +2344,6 @@ int audit_set_loginuid(kuid_t loginuid)
 int audit_signal_info(int sig, struct task_struct *t)
 {
 	kuid_t uid = current_uid(), auid;
-	struct lsmblob blob;
 
 	if (auditd_test_task(t) &&
 	    (sig == SIGTERM || sig == SIGHUP ||
@@ -2363,9 +2354,7 @@ int audit_signal_info(int sig, struct task_struct *t)
 			audit_sig_uid = auid;
 		else
 			audit_sig_uid = uid;
-		security_task_getsecid_subj(current, &blob);
-		/* scaffolding until audit_sig_sid is converted */
-		audit_sig_sid = blob.secid[0];
+		security_task_getsecid_subj(current, &audit_sig_lsm);
 	}
 
 	return audit_signal_info_syscall(t);
diff --git a/kernel/audit.h b/kernel/audit.h
index 1522e100fd17..23a85a470121 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -9,6 +9,7 @@
 #include <linux/fs.h>
 #include <linux/audit.h>
 #include <linux/skbuff.h>
+#include <linux/security.h>
 #include <uapi/linux/mqueue.h>
 #include <linux/tty.h>
 
@@ -134,7 +135,7 @@ struct audit_context {
 	kuid_t		    target_auid;
 	kuid_t		    target_uid;
 	unsigned int	    target_sessionid;
-	u32		    target_sid;
+	struct lsmblob	    target_lsm;
 	char		    target_comm[TASK_COMM_LEN];
 
 	struct audit_tree_refs *trees, *first_trees;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 6684927f12fc..573c6a8e505f 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -111,7 +111,7 @@ struct audit_aux_data_pids {
 	kuid_t			target_auid[AUDIT_AUX_PIDS];
 	kuid_t			target_uid[AUDIT_AUX_PIDS];
 	unsigned int		target_sessionid[AUDIT_AUX_PIDS];
-	u32			target_sid[AUDIT_AUX_PIDS];
+	struct lsmblob		target_lsm[AUDIT_AUX_PIDS];
 	char 			target_comm[AUDIT_AUX_PIDS][TASK_COMM_LEN];
 	int			pid_count;
 };
@@ -991,14 +991,14 @@ static inline void audit_free_context(struct audit_context *context)
 }
 
 static int audit_log_pid_context(struct audit_context *context, pid_t pid,
-				 kuid_t auid, kuid_t uid, unsigned int sessionid,
-				 u32 sid, char *comm)
+				 kuid_t auid, kuid_t uid,
+				 unsigned int sessionid,
+				 struct lsmblob *blob, char *comm)
 {
 	struct audit_buffer *ab;
 	char *ctx = NULL;
 	u32 len;
 	int rc = 0;
-	struct lsmblob blob;
 
 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
 	if (!ab)
@@ -1007,9 +1007,8 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 	audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
-	if (sid) {
-		lsmblob_init(&blob, sid);
-		if (security_secid_to_secctx(&blob, &ctx, &len)) {
+	if (lsmblob_is_set(blob)) {
+		if (security_secid_to_secctx(blob, &ctx, &len)) {
 			audit_log_format(ab, " obj=(none)");
 			rc = 1;
 		} else {
@@ -1580,7 +1579,7 @@ static void audit_log_exit(void)
 						  axs->target_auid[i],
 						  axs->target_uid[i],
 						  axs->target_sessionid[i],
-						  axs->target_sid[i],
+						  &axs->target_lsm[i],
 						  axs->target_comm[i]))
 				call_panic = 1;
 	}
@@ -1589,7 +1588,7 @@ static void audit_log_exit(void)
 	    audit_log_pid_context(context, context->target_pid,
 				  context->target_auid, context->target_uid,
 				  context->target_sessionid,
-				  context->target_sid, context->target_comm))
+				  &context->target_lsm, context->target_comm))
 			call_panic = 1;
 
 	if (context->pwd.dentry && context->pwd.mnt) {
@@ -1765,7 +1764,7 @@ void __audit_syscall_exit(int success, long return_code)
 	context->aux = NULL;
 	context->aux_pids = NULL;
 	context->target_pid = 0;
-	context->target_sid = 0;
+	lsmblob_init(&context->target_lsm, 0);
 	context->sockaddr_len = 0;
 	context->type = 0;
 	context->fds[0] = -1;
@@ -2319,6 +2318,7 @@ void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
 {
 	struct audit_context *context = audit_context();
 	struct lsmblob blob;
+
 	context->ipc.uid = ipcp->uid;
 	context->ipc.gid = ipcp->gid;
 	context->ipc.mode = ipcp->mode;
@@ -2417,15 +2417,12 @@ int __audit_sockaddr(int len, void *a)
 void __audit_ptrace(struct task_struct *t)
 {
 	struct audit_context *context = audit_context();
-	struct lsmblob blob;
 
 	context->target_pid = task_tgid_nr(t);
 	context->target_auid = audit_get_loginuid(t);
 	context->target_uid = task_uid(t);
 	context->target_sessionid = audit_get_sessionid(t);
-	security_task_getsecid_obj(t, &blob);
-	/* scaffolding - until target_sid is converted */
-	context->target_sid = blob.secid[0];
+	security_task_getsecid_obj(t, &context->target_lsm);
 	memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
 }
 
@@ -2441,7 +2438,6 @@ int audit_signal_info_syscall(struct task_struct *t)
 	struct audit_aux_data_pids *axp;
 	struct audit_context *ctx = audit_context();
 	kuid_t t_uid = task_uid(t);
-	struct lsmblob blob;
 
 	if (!audit_signals || audit_dummy_context())
 		return 0;
@@ -2453,9 +2449,7 @@ int audit_signal_info_syscall(struct task_struct *t)
 		ctx->target_auid = audit_get_loginuid(t);
 		ctx->target_uid = t_uid;
 		ctx->target_sessionid = audit_get_sessionid(t);
-		security_task_getsecid_obj(t, &blob);
-		/* scaffolding until target_sid is converted */
-		ctx->target_sid = blob.secid[0];
+		security_task_getsecid_obj(t, &ctx->target_lsm);
 		memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
 		return 0;
 	}
@@ -2476,9 +2470,7 @@ int audit_signal_info_syscall(struct task_struct *t)
 	axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
 	axp->target_uid[axp->pid_count] = t_uid;
 	axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
-	security_task_getsecid_obj(t, &blob);
-	/* scaffolding until target_sid is converted */
-	axp->target_sid[axp->pid_count] = blob.secid[0];
+	security_task_getsecid_obj(t, &axp->target_lsm[axp->pid_count]);
 	memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);
 	axp->pid_count++;
 
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 9d1ed00eb349..b3e00340a97c 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -470,7 +470,6 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 int ima_bprm_check(struct linux_binprm *bprm)
 {
 	int ret;
-	u32 secid;
 	struct lsmblob blob;
 
 	security_task_getsecid_subj(current, &blob);
@@ -480,9 +479,10 @@ int ima_bprm_check(struct linux_binprm *bprm)
 	if (ret)
 		return ret;
 
-	security_cred_getsecid(bprm->cred, &secid);
-	return process_measurement(bprm->file, bprm->cred, secid, NULL, 0,
-				   MAY_EXEC, CREDS_CHECK);
+	security_cred_getsecid(bprm->cred, &blob);
+	/* scaffolding until process_measurement changes */
+	return process_measurement(bprm->file, bprm->cred, blob.secid[0],
+				   NULL, 0, MAY_EXEC, CREDS_CHECK);
 }
 
 /**
diff --git a/security/security.c b/security/security.c
index 54f4a4ead69f..f5407a85641e 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1796,10 +1796,16 @@ void security_transfer_creds(struct cred *new, const struct cred *old)
 	call_void_hook(cred_transfer, new, old);
 }
 
-void security_cred_getsecid(const struct cred *c, u32 *secid)
+void security_cred_getsecid(const struct cred *c, struct lsmblob *blob)
 {
-	*secid = 0;
-	call_void_hook(cred_getsecid, c, secid);
+	struct security_hook_list *hp;
+
+	lsmblob_init(blob, 0);
+	hlist_for_each_entry(hp, &security_hook_heads.cred_getsecid, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		hp->hook.cred_getsecid(c, &blob->secid[hp->lsmid->slot]);
+	}
 }
 EXPORT_SYMBOL(security_cred_getsecid);
 
-- 
2.29.2

[PATCH v26 13/25] IMA: Change internal interfaces to use lsmblobs

[Casey Schaufler]

The IMA interfaces ima_get_action() and ima_match_policy()
call LSM functions that use lsmblobs. Change the IMA functions
to pass the lsmblob to be compatible with the LSM functions.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-integrity@vger.kernel.org
To: Mimi Zohar <zohar@linux.ibm.com>
---
 security/integrity/ima/ima.h          |  6 ++---
 security/integrity/ima/ima_api.c      |  6 ++---
 security/integrity/ima/ima_appraise.c |  5 ++--
 security/integrity/ima/ima_main.c     | 36 +++++++++++----------------
 security/integrity/ima/ima_policy.c   | 17 ++++++-------
 5 files changed, 31 insertions(+), 39 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 55f3bd4f0b01..a6b59fcaf62a 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -251,7 +251,7 @@ static inline void ima_process_queued_keys(void) {}
 
 /* LIM API function definitions */
 int ima_get_action(struct user_namespace *mnt_userns, struct inode *inode,
-		   const struct cred *cred, u32 secid, int mask,
+		   const struct cred *cred, struct lsmblob *blob, int mask,
 		   enum ima_hooks func, int *pcr,
 		   struct ima_template_desc **template_desc,
 		   const char *func_data);
@@ -282,8 +282,8 @@ const char *ima_d_path(const struct path *path, char **pathbuf, char *filename);
 
 /* IMA policy related functions */
 int ima_match_policy(struct user_namespace *mnt_userns, struct inode *inode,
-		     const struct cred *cred, u32 secid, enum ima_hooks func,
-		     int mask, int flags, int *pcr,
+		     const struct cred *cred, struct lsmblob *blob,
+		     enum ima_hooks func, int mask, int flags, int *pcr,
 		     struct ima_template_desc **template_desc,
 		     const char *func_data);
 void ima_init_policy(void);
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index d8e321cc6936..691f68d478f1 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -165,7 +165,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
  * @mnt_userns:	user namespace of the mount the inode was found from
  * @inode: pointer to the inode associated with the object being validated
  * @cred: pointer to credentials structure to validate
- * @secid: secid of the task being validated
+ * @blob: LSM data of the task being validated
  * @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXEC,
  *        MAY_APPEND)
  * @func: caller identifier
@@ -185,7 +185,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
  *
  */
 int ima_get_action(struct user_namespace *mnt_userns, struct inode *inode,
-		   const struct cred *cred, u32 secid, int mask,
+		   const struct cred *cred, struct lsmblob *blob, int mask,
 		   enum ima_hooks func, int *pcr,
 		   struct ima_template_desc **template_desc,
 		   const char *func_data)
@@ -194,7 +194,7 @@ int ima_get_action(struct user_namespace *mnt_userns, struct inode *inode,
 
 	flags &= ima_policy_flag;
 
-	return ima_match_policy(mnt_userns, inode, cred, secid, func, mask,
+	return ima_match_policy(mnt_userns, inode, cred, blob, func, mask,
 				flags, pcr, template_desc, func_data);
 }
 
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index f8c7b593175f..b2af72289f00 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -77,10 +77,9 @@ int ima_must_appraise(struct user_namespace *mnt_userns, struct inode *inode,
 		return 0;
 
 	security_task_getsecid_subj(current, &blob);
-	/* scaffolding the .secid[0] */
 	return ima_match_policy(mnt_userns, inode, current_cred(),
-				blob.secid[0], func, mask,
-				IMA_APPRAISE | IMA_HASH, NULL, NULL, NULL);
+				&blob, func, mask, IMA_APPRAISE | IMA_HASH,
+				NULL, NULL, NULL);
 }
 
 static int ima_fix_xattr(struct dentry *dentry,
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index b3e00340a97c..b63f73d43bd2 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -194,8 +194,8 @@ void ima_file_free(struct file *file)
 }
 
 static int process_measurement(struct file *file, const struct cred *cred,
-			       u32 secid, char *buf, loff_t size, int mask,
-			       enum ima_hooks func)
+			       struct lsmblob *blob, char *buf, loff_t size,
+			       int mask, enum ima_hooks func)
 {
 	struct inode *inode = file_inode(file);
 	struct integrity_iint_cache *iint = NULL;
@@ -218,7 +218,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
 	 * bitmask based on the appraise/audit/measurement policy.
 	 * Included is the appraise submask.
 	 */
-	action = ima_get_action(file_mnt_user_ns(file), inode, cred, secid,
+	action = ima_get_action(file_mnt_user_ns(file), inode, cred, blob,
 				mask, func, &pcr, &template_desc, NULL);
 	violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) &&
 			   (ima_policy_flag & IMA_MEASURE));
@@ -392,8 +392,7 @@ int ima_file_mmap(struct file *file, unsigned long prot)
 
 	if (file && (prot & PROT_EXEC)) {
 		security_task_getsecid_subj(current, &blob);
-		/* scaffolding - until process_measurement changes */
-		return process_measurement(file, current_cred(), blob.secid[0],
+		return process_measurement(file, current_cred(), &blob,
 					   NULL, 0, MAY_EXEC, MMAP_CHECK);
 	}
 
@@ -434,7 +433,7 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 	inode = file_inode(vma->vm_file);
 	/* scaffolding */
 	action = ima_get_action(file_mnt_user_ns(vma->vm_file), inode,
-				current_cred(), blob.secid[0], MAY_EXEC,
+				current_cred(), &blob, MAY_EXEC,
 				MMAP_CHECK, &pcr, &template, 0);
 
 	/* Is the mmap'ed file in policy? */
@@ -473,16 +472,14 @@ int ima_bprm_check(struct linux_binprm *bprm)
 	struct lsmblob blob;
 
 	security_task_getsecid_subj(current, &blob);
-	/* scaffolding until process_measurement changes */
-	ret = process_measurement(bprm->file, current_cred(), blob.secid[0],
-				  NULL, 0, MAY_EXEC, BPRM_CHECK);
+	ret = process_measurement(bprm->file, current_cred(), &blob, NULL, 0,
+				  MAY_EXEC, BPRM_CHECK);
 	if (ret)
 		return ret;
 
 	security_cred_getsecid(bprm->cred, &blob);
-	/* scaffolding until process_measurement changes */
-	return process_measurement(bprm->file, bprm->cred, blob.secid[0],
-				   NULL, 0, MAY_EXEC, CREDS_CHECK);
+	return process_measurement(bprm->file, bprm->cred, &blob, NULL, 0,
+				   MAY_EXEC, CREDS_CHECK);
 }
 
 /**
@@ -500,8 +497,7 @@ int ima_file_check(struct file *file, int mask)
 	struct lsmblob blob;
 
 	security_task_getsecid_subj(current, &blob);
-	/* scaffolding until process_measurement changes */
-	return process_measurement(file, current_cred(), blob.secid[0], NULL, 0,
+	return process_measurement(file, current_cred(), &blob, NULL, 0,
 				   mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
 					   MAY_APPEND), FILE_CHECK);
 }
@@ -698,9 +694,8 @@ int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
 	/* Read entire file for all partial reads. */
 	func = read_idmap[read_id] ?: FILE_CHECK;
 	security_task_getsecid_subj(current, &blob);
-	/* scaffolding - until process_measurement changes */
-	return process_measurement(file, current_cred(), blob.secid[0], NULL,
-				   0, MAY_READ, func);
+	return process_measurement(file, current_cred(), &blob, NULL, 0,
+				   MAY_READ, func);
 }
 
 const int read_idmap[READING_MAX_ID] = {
@@ -742,9 +737,8 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
 
 	func = read_idmap[read_id] ?: FILE_CHECK;
 	security_task_getsecid_subj(current, &blob);
-	/* scaffolding until process_measurement changes */
-	return process_measurement(file, current_cred(), blob.secid[0], buf,
-				   size, MAY_READ, func);
+	return process_measurement(file, current_cred(), &blob, buf, size,
+				   MAY_READ, func);
 }
 
 /**
@@ -889,7 +883,7 @@ void process_buffer_measurement(struct user_namespace *mnt_userns,
 		security_task_getsecid_subj(current, &blob);
 		/* scaffolding */
 		action = ima_get_action(mnt_userns, inode, current_cred(),
-					blob.secid[0], 0, func, &pcr, &template,
+					&blob, 0, func, &pcr, &template,
 					func_data);
 		if (!(action & IMA_MEASURE))
 			return;
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 5ee7629fd782..caacd8bf0462 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -546,7 +546,7 @@ static bool ima_match_rule_data(struct ima_rule_entry *rule,
  * @mnt_userns:	user namespace of the mount the inode was found from
  * @inode: a pointer to an inode
  * @cred: a pointer to a credentials structure for user validation
- * @secid: the secid of the task to be validated
+ * @blob: the lsm data of the task to be validated
  * @func: LIM hook identifier
  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
  * @func_data: func specific data, may be NULL
@@ -556,8 +556,8 @@ static bool ima_match_rule_data(struct ima_rule_entry *rule,
 static bool ima_match_rules(struct ima_rule_entry *rule,
 			    struct user_namespace *mnt_userns,
 			    struct inode *inode, const struct cred *cred,
-			    u32 secid, enum ima_hooks func, int mask,
-			    const char *func_data)
+			    struct lsmblob *blob, enum ima_hooks func,
+			    int mask, const char *func_data)
 {
 	int i;
 
@@ -626,8 +626,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
 		case LSM_SUBJ_USER:
 		case LSM_SUBJ_ROLE:
 		case LSM_SUBJ_TYPE:
-			lsmblob_init(&lsmdata, secid);
-			rc = ima_filter_rule_match(&lsmdata, rule->lsm[i].type,
+			rc = ima_filter_rule_match(blob, rule->lsm[i].type,
 						   Audit_equal,
 						   rule->lsm[i].rule);
 			break;
@@ -671,7 +670,7 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
  * @inode: pointer to an inode for which the policy decision is being made
  * @cred: pointer to a credentials structure for which the policy decision is
  *        being made
- * @secid: LSM secid of the task to be validated
+ * @blob: LSM data of the task to be validated
  * @func: IMA hook identifier
  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
  * @pcr: set the pcr to extend
@@ -686,8 +685,8 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
  * than writes so ima_match_policy() is classical RCU candidate.
  */
 int ima_match_policy(struct user_namespace *mnt_userns, struct inode *inode,
-		     const struct cred *cred, u32 secid, enum ima_hooks func,
-		     int mask, int flags, int *pcr,
+		     const struct cred *cred, struct lsmblob *blob,
+		     enum ima_hooks func, int mask, int flags, int *pcr,
 		     struct ima_template_desc **template_desc,
 		     const char *func_data)
 {
@@ -703,7 +702,7 @@ int ima_match_policy(struct user_namespace *mnt_userns, struct inode *inode,
 		if (!(entry->action & actmask))
 			continue;
 
-		if (!ima_match_rules(entry, mnt_userns, inode, cred, secid,
+		if (!ima_match_rules(entry, mnt_userns, inode, cred, blob,
 				     func, mask, func_data))
 			continue;
 
-- 
2.29.2

[PATCH v26 14/25] LSM: Specify which LSM to display

[Casey Schaufler]

Create a new entry "interface_lsm" in the procfs attr directory for
controlling which LSM security information is displayed for a
process. A process can only read or write its own display value.

The name of an active LSM that supplies hooks for
human readable data may be written to "interface_lsm" to set the
value. The name of the LSM currently in use can be read from
"interface_lsm". At this point there can only be one LSM capable
of display active. A helper function lsm_task_ilsm() is
provided to get the interface lsm slot for a task_struct.

Setting the "interface_lsm" requires that all security modules using
setprocattr hooks allow the action. Each security module is
responsible for defining its policy.

AppArmor hook provided by John Johansen <john.johansen@canonical.com>
SELinux hook provided by Stephen Smalley <stephen.smalley.work@gmail.com>

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-api@vger.kernel.org
Cc: linux-doc@vger.kernel.org
---
 .../ABI/testing/procfs-attr-lsm_display       |  22 +++
 Documentation/security/lsm.rst                |  14 ++
 fs/proc/base.c                                |   1 +
 include/linux/lsm_hooks.h                     |  17 ++
 security/apparmor/include/apparmor.h          |   3 +-
 security/apparmor/lsm.c                       |  32 ++++
 security/security.c                           | 166 ++++++++++++++++--
 security/selinux/hooks.c                      |  11 ++
 security/selinux/include/classmap.h           |   2 +-
 security/smack/smack_lsm.c                    |   7 +
 10 files changed, 256 insertions(+), 19 deletions(-)
 create mode 100644 Documentation/ABI/testing/procfs-attr-lsm_display

diff --git a/Documentation/ABI/testing/procfs-attr-lsm_display b/Documentation/ABI/testing/procfs-attr-lsm_display
new file mode 100644
index 000000000000..0f60005c235c
--- /dev/null
+++ b/Documentation/ABI/testing/procfs-attr-lsm_display
@@ -0,0 +1,22 @@
+What:		/proc/*/attr/lsm_display
+Contact:	linux-security-module@vger.kernel.org,
+Description:	The name of the Linux security module (LSM) that will
+		provide information in the /proc/*/attr/current,
+		/proc/*/attr/prev and /proc/*/attr/exec interfaces.
+		The details of permissions required to read from
+		this interface are dependent on the LSMs active on the
+		system.
+		A process cannot write to this interface unless it
+		refers to itself.
+		The other details of permissions required to write to
+		this interface are dependent on the LSMs active on the
+		system.
+		The format of the data used by this interface is a
+		text string identifying the name of an LSM. The values
+		accepted are:
+			selinux		- the SELinux LSM
+			smack		- the Smack LSM
+			apparmor	- The AppArmor LSM
+		By convention the LSM names are lower case and do not
+		contain special characters.
+Users:		LSM user-space
diff --git a/Documentation/security/lsm.rst b/Documentation/security/lsm.rst
index 6a2a2e973080..b77b4a540391 100644
--- a/Documentation/security/lsm.rst
+++ b/Documentation/security/lsm.rst
@@ -129,3 +129,17 @@ to identify it as the first security module to be registered.
 The capabilities security module does not use the general security
 blobs, unlike other modules. The reasons are historical and are
 based on overhead, complexity and performance concerns.
+
+LSM External Interfaces
+=======================
+
+The LSM infrastructure does not generally provide external interfaces.
+The individual security modules provide what external interfaces they
+require.
+
+The file ``/sys/kernel/security/lsm`` provides a comma
+separated list of the active security modules.
+
+The file ``/proc/pid/attr/interface_lsm`` contains the name of the security
+module for which the ``/proc/pid/attr/current`` interface will
+apply. This interface can be written to.
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 3851bfcdba56..10de522f3112 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2807,6 +2807,7 @@ static const struct pid_entry attr_dir_stuff[] = {
 	ATTR(NULL, "fscreate",		0666),
 	ATTR(NULL, "keycreate",		0666),
 	ATTR(NULL, "sockcreate",	0666),
+	ATTR(NULL, "interface_lsm",	0666),
 #ifdef CONFIG_SECURITY_SMACK
 	DIR("smack",			0555,
 	    proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops),
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index c61a16f0a5bc..d2c4bc94d47f 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1686,4 +1686,21 @@ static inline void security_delete_hooks(struct security_hook_list *hooks,
 
 extern int lsm_inode_alloc(struct inode *inode);
 
+/**
+ * lsm_task_ilsm - the "interface_lsm" for this task
+ * @task: The task to report on
+ *
+ * Returns the task's interface LSM slot.
+ */
+static inline int lsm_task_ilsm(struct task_struct *task)
+{
+#ifdef CONFIG_SECURITY
+	int *ilsm = task->security;
+
+	if (ilsm)
+		return *ilsm;
+#endif
+	return LSMBLOB_INVALID;
+}
+
 #endif /* ! __LINUX_LSM_HOOKS_H */
diff --git a/security/apparmor/include/apparmor.h b/security/apparmor/include/apparmor.h
index 1fbabdb565a8..b1622fcb4394 100644
--- a/security/apparmor/include/apparmor.h
+++ b/security/apparmor/include/apparmor.h
@@ -28,8 +28,9 @@
 #define AA_CLASS_SIGNAL		10
 #define AA_CLASS_NET		14
 #define AA_CLASS_LABEL		16
+#define AA_CLASS_DISPLAY_LSM	17
 
-#define AA_CLASS_LAST		AA_CLASS_LABEL
+#define AA_CLASS_LAST		AA_CLASS_DISPLAY_LSM
 
 /* Control parameters settable through module/boot flags */
 extern enum audit_mode aa_g_audit;
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 392e25940d1f..4237536106aa 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -621,6 +621,25 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
 	return error;
 }
 
+
+static int profile_interface_lsm(struct aa_profile *profile,
+				 struct common_audit_data *sa)
+{
+	struct aa_perms perms = { };
+	unsigned int state;
+
+	state = PROFILE_MEDIATES(profile, AA_CLASS_DISPLAY_LSM);
+	if (state) {
+		aa_compute_perms(profile->policy.dfa, state, &perms);
+		aa_apply_modes_to_perms(profile, &perms);
+		aad(sa)->label = &profile->label;
+
+		return aa_check_perms(profile, &perms, AA_MAY_WRITE, sa, NULL);
+	}
+
+	return 0;
+}
+
 static int apparmor_setprocattr(const char *name, void *value,
 				size_t size)
 {
@@ -632,6 +651,19 @@ static int apparmor_setprocattr(const char *name, void *value,
 	if (size == 0)
 		return -EINVAL;
 
+	/* LSM infrastructure does actual setting of interface_lsm if allowed */
+	if (!strcmp(name, "interface_lsm")) {
+		struct aa_profile *profile;
+		struct aa_label *label;
+
+		aad(&sa)->info = "set interface lsm";
+		label = begin_current_label_crit_section();
+		error = fn_for_each_confined(label, profile,
+					profile_interface_lsm(profile, &sa));
+		end_current_label_crit_section(label);
+		return error;
+	}
+
 	/* AppArmor requires that the buffer must be null terminated atm */
 	if (args[size - 1] != '\0') {
 		/* null terminate */
diff --git a/security/security.c b/security/security.c
index f5407a85641e..1ce125c01782 100644
--- a/security/security.c
+++ b/security/security.c
@@ -77,7 +77,16 @@ static struct kmem_cache *lsm_file_cache;
 static struct kmem_cache *lsm_inode_cache;
 
 char *lsm_names;
-static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init;
+
+/*
+ * The task blob includes the "interface_lsm" slot used for
+ * chosing which module presents contexts.
+ * Using a long to avoid potential alignment issues with
+ * module assigned task blobs.
+ */
+static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init = {
+	.lbs_task = sizeof(long),
+};
 
 /* Boot-time LSM user choice */
 static __initdata const char *chosen_lsm_order;
@@ -669,6 +678,8 @@ int lsm_inode_alloc(struct inode *inode)
  */
 static int lsm_task_alloc(struct task_struct *task)
 {
+	int *ilsm;
+
 	if (blob_sizes.lbs_task == 0) {
 		task->security = NULL;
 		return 0;
@@ -677,6 +688,15 @@ static int lsm_task_alloc(struct task_struct *task)
 	task->security = kzalloc(blob_sizes.lbs_task, GFP_KERNEL);
 	if (task->security == NULL)
 		return -ENOMEM;
+
+	/*
+	 * The start of the task blob contains the "interface" LSM slot number.
+	 * Start with it set to the invalid slot number, indicating that the
+	 * default first registered LSM be displayed.
+	 */
+	ilsm = task->security;
+	*ilsm = LSMBLOB_INVALID;
+
 	return 0;
 }
 
@@ -1732,14 +1752,26 @@ int security_file_open(struct file *file)
 
 int security_task_alloc(struct task_struct *task, unsigned long clone_flags)
 {
+	int *oilsm = current->security;
+	int *nilsm;
 	int rc = lsm_task_alloc(task);
 
-	if (rc)
+	if (unlikely(rc))
 		return rc;
+
 	rc = call_int_hook(task_alloc, 0, task, clone_flags);
-	if (unlikely(rc))
+	if (unlikely(rc)) {
 		security_task_free(task);
-	return rc;
+		return rc;
+	}
+
+	if (oilsm) {
+		nilsm = task->security;
+		if (nilsm)
+			*nilsm = *oilsm;
+	}
+
+	return 0;
 }
 
 void security_task_free(struct task_struct *task)
@@ -2171,23 +2203,110 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
 				char **value)
 {
 	struct security_hook_list *hp;
+	int ilsm = lsm_task_ilsm(current);
+	int slot = 0;
+
+	if (!strcmp(name, "interface_lsm")) {
+		/*
+		 * lsm_slot will be 0 if there are no displaying modules.
+		 */
+		if (lsm_slot == 0)
+			return -EINVAL;
+
+		/*
+		 * Only allow getting the current process' interface_lsm.
+		 * There are too few reasons to get another process'
+		 * interface_lsm and too many LSM policy issues.
+		 */
+		if (current != p)
+			return -EINVAL;
+
+		ilsm = lsm_task_ilsm(p);
+		if (ilsm != LSMBLOB_INVALID)
+			slot = ilsm;
+		*value = kstrdup(lsm_slotlist[slot]->lsm, GFP_KERNEL);
+		if (*value)
+			return strlen(*value);
+		return -ENOMEM;
+	}
 
 	hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
 		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
 			continue;
+		if (lsm == NULL && ilsm != LSMBLOB_INVALID &&
+		    ilsm != hp->lsmid->slot)
+			continue;
 		return hp->hook.getprocattr(p, name, value);
 	}
 	return LSM_RET_DEFAULT(getprocattr);
 }
 
+/**
+ * security_setprocattr - Set process attributes via /proc
+ * @lsm: name of module involved, or NULL
+ * @name: name of the attribute
+ * @value: value to set the attribute to
+ * @size: size of the value
+ *
+ * Set the process attribute for the specified security module
+ * to the specified value. Note that this can only be used to set
+ * the process attributes for the current, or "self" process.
+ * The /proc code has already done this check.
+ *
+ * Returns 0 on success, an appropriate code otherwise.
+ */
 int security_setprocattr(const char *lsm, const char *name, void *value,
 			 size_t size)
 {
 	struct security_hook_list *hp;
+	char *termed;
+	char *copy;
+	int *ilsm = current->security;
+	int rc = -EINVAL;
+	int slot = 0;
+
+	if (!strcmp(name, "interface_lsm")) {
+		/*
+		 * Change the "interface_lsm" value only if all the security
+		 * modules that support setting a procattr allow it.
+		 * It is assumed that all such security modules will be
+		 * cooperative.
+		 */
+		if (size == 0)
+			return -EINVAL;
+
+		hlist_for_each_entry(hp, &security_hook_heads.setprocattr,
+				     list) {
+			rc = hp->hook.setprocattr(name, value, size);
+			if (rc < 0)
+				return rc;
+		}
+
+		rc = -EINVAL;
+
+		copy = kmemdup_nul(value, size, GFP_KERNEL);
+		if (copy == NULL)
+			return -ENOMEM;
+
+		termed = strsep(&copy, " \n");
+
+		for (slot = 0; slot < lsm_slot; slot++)
+			if (!strcmp(termed, lsm_slotlist[slot]->lsm)) {
+				*ilsm = lsm_slotlist[slot]->slot;
+				rc = size;
+				break;
+			}
+
+		kfree(termed);
+		return rc;
+	}
 
 	hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) {
 		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
 			continue;
+		if (lsm == NULL && *ilsm != LSMBLOB_INVALID &&
+		    *ilsm != hp->lsmid->slot)
+			continue;
 		return hp->hook.setprocattr(name, value, size);
 	}
 	return LSM_RET_DEFAULT(setprocattr);
@@ -2207,15 +2326,15 @@ EXPORT_SYMBOL(security_ismaclabel);
 int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen)
 {
 	struct security_hook_list *hp;
-	int rc;
+	int ilsm = lsm_task_ilsm(current);
 
 	hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
-		rc = hp->hook.secid_to_secctx(blob->secid[hp->lsmid->slot],
-					      secdata, seclen);
-		if (rc != LSM_RET_DEFAULT(secid_to_secctx))
-			return rc;
+		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
+			return hp->hook.secid_to_secctx(
+					blob->secid[hp->lsmid->slot],
+					secdata, seclen);
 	}
 
 	return LSM_RET_DEFAULT(secid_to_secctx);
@@ -2226,16 +2345,15 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
 			     struct lsmblob *blob)
 {
 	struct security_hook_list *hp;
-	int rc;
+	int ilsm = lsm_task_ilsm(current);
 
 	lsmblob_init(blob, 0);
 	hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
-		rc = hp->hook.secctx_to_secid(secdata, seclen,
-					      &blob->secid[hp->lsmid->slot]);
-		if (rc != 0)
-			return rc;
+		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
+			return hp->hook.secctx_to_secid(secdata, seclen,
+						&blob->secid[hp->lsmid->slot]);
 	}
 	return 0;
 }
@@ -2243,7 +2361,14 @@ EXPORT_SYMBOL(security_secctx_to_secid);
 
 void security_release_secctx(char *secdata, u32 seclen)
 {
-	call_void_hook(release_secctx, secdata, seclen);
+	struct security_hook_list *hp;
+	int ilsm = lsm_task_ilsm(current);
+
+	hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list)
+		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot) {
+			hp->hook.release_secctx(secdata, seclen);
+			return;
+		}
 }
 EXPORT_SYMBOL(security_release_secctx);
 
@@ -2384,8 +2509,15 @@ EXPORT_SYMBOL(security_sock_rcv_skb);
 int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
 				      int __user *optlen, unsigned len)
 {
-	return call_int_hook(socket_getpeersec_stream, -ENOPROTOOPT, sock,
-				optval, optlen, len);
+	int ilsm = lsm_task_ilsm(current);
+	struct security_hook_list *hp;
+
+	hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_stream,
+			     list)
+		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
+			return hp->hook.socket_getpeersec_stream(sock, optval,
+								 optlen, len);
+	return -ENOPROTOOPT;
 }
 
 int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 0133b142e938..dba867721336 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6510,6 +6510,17 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
 	/*
 	 * Basic control over ability to set these attributes at all.
 	 */
+
+	/*
+	 * For setting interface_lsm, we only perform a permission check;
+	 * the actual update to the interface_lsm value is handled by the
+	 * LSM framework.
+	 */
+	if (!strcmp(name, "interface_lsm"))
+		return avc_has_perm(&selinux_state,
+				    mysid, mysid, SECCLASS_PROCESS2,
+				    PROCESS2__SETDISPLAY, NULL);
+
 	if (!strcmp(name, "exec"))
 		error = avc_has_perm(&selinux_state,
 				     mysid, mysid, SECCLASS_PROCESS,
diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
index 62d19bccf3de..8f4b0dd6dd78 100644
--- a/security/selinux/include/classmap.h
+++ b/security/selinux/include/classmap.h
@@ -53,7 +53,7 @@ struct security_class_mapping secclass_map[] = {
 	    "execmem", "execstack", "execheap", "setkeycreate",
 	    "setsockcreate", "getrlimit", NULL } },
 	{ "process2",
-	  { "nnp_transition", "nosuid_transition", NULL } },
+	  { "nnp_transition", "nosuid_transition", "setdisplay", NULL } },
 	{ "system",
 	  { "ipc_info", "syslog_read", "syslog_mod",
 	    "syslog_console", "module_request", "module_load", NULL } },
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 5c10ad27be37..7aa7ea38f627 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3508,6 +3508,13 @@ static int smack_setprocattr(const char *name, void *value, size_t size)
 	struct smack_known_list_elem *sklep;
 	int rc;
 
+	/*
+	 * Allow the /proc/.../attr/current and SO_PEERSEC "interface_lsm"
+	 * to be reset at will.
+	 */
+	if (strcmp(name, "interface_lsm") == 0)
+		return 0;
+
 	if (!smack_privileged(CAP_MAC_ADMIN) && list_empty(&tsp->smk_relabel))
 		return -EPERM;
 
-- 
2.29.2

Re: [PATCH v26 14/25] LSM: Specify which LSM to display

[Kees Cook]

On Thu, May 13, 2021 at 01:07:56PM -0700, Casey Schaufler wrote:
> Create a new entry "interface_lsm" in the procfs attr directory for
> controlling which LSM security information is displayed for a
> process. A process can only read or write its own display value.
> 
> The name of an active LSM that supplies hooks for
> human readable data may be written to "interface_lsm" to set the
> value. The name of the LSM currently in use can be read from
> "interface_lsm". At this point there can only be one LSM capable
> of display active. A helper function lsm_task_ilsm() is
> provided to get the interface lsm slot for a task_struct.
> 
> Setting the "interface_lsm" requires that all security modules using
> setprocattr hooks allow the action. Each security module is
> responsible for defining its policy.
> 
> AppArmor hook provided by John Johansen <john.johansen@canonical.com>
> SELinux hook provided by Stephen Smalley <stephen.smalley.work@gmail.com>
> 
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
> Cc: Paul Moore <paul@paul-moore.com>
> Cc: John Johansen <john.johansen@canonical.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-api@vger.kernel.org
> Cc: linux-doc@vger.kernel.org
> ---
>  .../ABI/testing/procfs-attr-lsm_display       |  22 +++
>  Documentation/security/lsm.rst                |  14 ++
>  fs/proc/base.c                                |   1 +
>  include/linux/lsm_hooks.h                     |  17 ++
>  security/apparmor/include/apparmor.h          |   3 +-
>  security/apparmor/lsm.c                       |  32 ++++
>  security/security.c                           | 166 ++++++++++++++++--
>  security/selinux/hooks.c                      |  11 ++
>  security/selinux/include/classmap.h           |   2 +-
>  security/smack/smack_lsm.c                    |   7 +
>  10 files changed, 256 insertions(+), 19 deletions(-)
>  create mode 100644 Documentation/ABI/testing/procfs-attr-lsm_display
> 
> diff --git a/Documentation/ABI/testing/procfs-attr-lsm_display b/Documentation/ABI/testing/procfs-attr-lsm_display
> new file mode 100644
> index 000000000000..0f60005c235c
> --- /dev/null
> +++ b/Documentation/ABI/testing/procfs-attr-lsm_display
> @@ -0,0 +1,22 @@
> +What:		/proc/*/attr/lsm_display
> +Contact:	linux-security-module@vger.kernel.org,
> +Description:	The name of the Linux security module (LSM) that will
> +		provide information in the /proc/*/attr/current,
> +		/proc/*/attr/prev and /proc/*/attr/exec interfaces.
> +		The details of permissions required to read from
> +		this interface are dependent on the LSMs active on the
> +		system.
> +		A process cannot write to this interface unless it
> +		refers to itself.
> +		The other details of permissions required to write to
> +		this interface are dependent on the LSMs active on the
> +		system.
> +		The format of the data used by this interface is a
> +		text string identifying the name of an LSM. The values
> +		accepted are:
> +			selinux		- the SELinux LSM
> +			smack		- the Smack LSM
> +			apparmor	- The AppArmor LSM
> +		By convention the LSM names are lower case and do not
> +		contain special characters.
> +Users:		LSM user-space
> diff --git a/Documentation/security/lsm.rst b/Documentation/security/lsm.rst
> index 6a2a2e973080..b77b4a540391 100644
> --- a/Documentation/security/lsm.rst
> +++ b/Documentation/security/lsm.rst
> @@ -129,3 +129,17 @@ to identify it as the first security module to be registered.
>  The capabilities security module does not use the general security
>  blobs, unlike other modules. The reasons are historical and are
>  based on overhead, complexity and performance concerns.
> +
> +LSM External Interfaces
> +=======================
> +
> +The LSM infrastructure does not generally provide external interfaces.
> +The individual security modules provide what external interfaces they
> +require.
> +
> +The file ``/sys/kernel/security/lsm`` provides a comma
> +separated list of the active security modules.
> +
> +The file ``/proc/pid/attr/interface_lsm`` contains the name of the security
> +module for which the ``/proc/pid/attr/current`` interface will
> +apply. This interface can be written to.
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index 3851bfcdba56..10de522f3112 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -2807,6 +2807,7 @@ static const struct pid_entry attr_dir_stuff[] = {
>  	ATTR(NULL, "fscreate",		0666),
>  	ATTR(NULL, "keycreate",		0666),
>  	ATTR(NULL, "sockcreate",	0666),
> +	ATTR(NULL, "interface_lsm",	0666),

Anyone can open this file... (continued below)

>  #ifdef CONFIG_SECURITY_SMACK
>  	DIR("smack",			0555,
>  	    proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops),
> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> index c61a16f0a5bc..d2c4bc94d47f 100644
> --- a/include/linux/lsm_hooks.h
> +++ b/include/linux/lsm_hooks.h
> @@ -1686,4 +1686,21 @@ static inline void security_delete_hooks(struct security_hook_list *hooks,
>  
>  extern int lsm_inode_alloc(struct inode *inode);
>  
> +/**
> + * lsm_task_ilsm - the "interface_lsm" for this task
> + * @task: The task to report on
> + *
> + * Returns the task's interface LSM slot.
> + */
> +static inline int lsm_task_ilsm(struct task_struct *task)
> +{
> +#ifdef CONFIG_SECURITY
> +	int *ilsm = task->security;
> +
> +	if (ilsm)
> +		return *ilsm;
> +#endif
> +	return LSMBLOB_INVALID;
> +}
> +
>  #endif /* ! __LINUX_LSM_HOOKS_H */
> diff --git a/security/apparmor/include/apparmor.h b/security/apparmor/include/apparmor.h
> index 1fbabdb565a8..b1622fcb4394 100644
> --- a/security/apparmor/include/apparmor.h
> +++ b/security/apparmor/include/apparmor.h
> @@ -28,8 +28,9 @@
>  #define AA_CLASS_SIGNAL		10
>  #define AA_CLASS_NET		14
>  #define AA_CLASS_LABEL		16
> +#define AA_CLASS_DISPLAY_LSM	17
>  
> -#define AA_CLASS_LAST		AA_CLASS_LABEL
> +#define AA_CLASS_LAST		AA_CLASS_DISPLAY_LSM
>  
>  /* Control parameters settable through module/boot flags */
>  extern enum audit_mode aa_g_audit;
> diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
> index 392e25940d1f..4237536106aa 100644
> --- a/security/apparmor/lsm.c
> +++ b/security/apparmor/lsm.c
> @@ -621,6 +621,25 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
>  	return error;
>  }
>  
> +
> +static int profile_interface_lsm(struct aa_profile *profile,
> +				 struct common_audit_data *sa)
> +{
> +	struct aa_perms perms = { };
> +	unsigned int state;
> +
> +	state = PROFILE_MEDIATES(profile, AA_CLASS_DISPLAY_LSM);
> +	if (state) {
> +		aa_compute_perms(profile->policy.dfa, state, &perms);
> +		aa_apply_modes_to_perms(profile, &perms);
> +		aad(sa)->label = &profile->label;
> +
> +		return aa_check_perms(profile, &perms, AA_MAY_WRITE, sa, NULL);
> +	}
> +
> +	return 0;
> +}
> +
>  static int apparmor_setprocattr(const char *name, void *value,
>  				size_t size)
>  {
> @@ -632,6 +651,19 @@ static int apparmor_setprocattr(const char *name, void *value,
>  	if (size == 0)
>  		return -EINVAL;
>  
> +	/* LSM infrastructure does actual setting of interface_lsm if allowed */
> +	if (!strcmp(name, "interface_lsm")) {
> +		struct aa_profile *profile;
> +		struct aa_label *label;
> +
> +		aad(&sa)->info = "set interface lsm";
> +		label = begin_current_label_crit_section();
> +		error = fn_for_each_confined(label, profile,
> +					profile_interface_lsm(profile, &sa));
> +		end_current_label_crit_section(label);
> +		return error;
> +	}
> +
>  	/* AppArmor requires that the buffer must be null terminated atm */
>  	if (args[size - 1] != '\0') {
>  		/* null terminate */
> diff --git a/security/security.c b/security/security.c
> index f5407a85641e..1ce125c01782 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -77,7 +77,16 @@ static struct kmem_cache *lsm_file_cache;
>  static struct kmem_cache *lsm_inode_cache;
>  
>  char *lsm_names;
> -static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init;
> +
> +/*
> + * The task blob includes the "interface_lsm" slot used for
> + * chosing which module presents contexts.
> + * Using a long to avoid potential alignment issues with
> + * module assigned task blobs.
> + */
> +static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init = {
> +	.lbs_task = sizeof(long),
> +};
>  
>  /* Boot-time LSM user choice */
>  static __initdata const char *chosen_lsm_order;
> @@ -669,6 +678,8 @@ int lsm_inode_alloc(struct inode *inode)
>   */
>  static int lsm_task_alloc(struct task_struct *task)
>  {
> +	int *ilsm;
> +
>  	if (blob_sizes.lbs_task == 0) {
>  		task->security = NULL;
>  		return 0;
> @@ -677,6 +688,15 @@ static int lsm_task_alloc(struct task_struct *task)
>  	task->security = kzalloc(blob_sizes.lbs_task, GFP_KERNEL);
>  	if (task->security == NULL)
>  		return -ENOMEM;
> +
> +	/*
> +	 * The start of the task blob contains the "interface" LSM slot number.
> +	 * Start with it set to the invalid slot number, indicating that the
> +	 * default first registered LSM be displayed.
> +	 */
> +	ilsm = task->security;
> +	*ilsm = LSMBLOB_INVALID;
> +
>  	return 0;
>  }
>  
> @@ -1732,14 +1752,26 @@ int security_file_open(struct file *file)
>  
>  int security_task_alloc(struct task_struct *task, unsigned long clone_flags)
>  {
> +	int *oilsm = current->security;
> +	int *nilsm;
>  	int rc = lsm_task_alloc(task);
>  
> -	if (rc)
> +	if (unlikely(rc))
>  		return rc;
> +
>  	rc = call_int_hook(task_alloc, 0, task, clone_flags);
> -	if (unlikely(rc))
> +	if (unlikely(rc)) {
>  		security_task_free(task);
> -	return rc;
> +		return rc;
> +	}
> +
> +	if (oilsm) {
> +		nilsm = task->security;
> +		if (nilsm)
> +			*nilsm = *oilsm;
> +	}
> +
> +	return 0;
>  }
>  
>  void security_task_free(struct task_struct *task)
> @@ -2171,23 +2203,110 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
>  				char **value)
>  {
>  	struct security_hook_list *hp;
> +	int ilsm = lsm_task_ilsm(current);
> +	int slot = 0;
> +
> +	if (!strcmp(name, "interface_lsm")) {
> +		/*
> +		 * lsm_slot will be 0 if there are no displaying modules.
> +		 */
> +		if (lsm_slot == 0)
> +			return -EINVAL;
> +
> +		/*
> +		 * Only allow getting the current process' interface_lsm.
> +		 * There are too few reasons to get another process'
> +		 * interface_lsm and too many LSM policy issues.
> +		 */
> +		if (current != p)
> +			return -EINVAL;

... but context isn't established by just checking "current", as this
file handle may have been given to another process.

I suspect the security_get/setprocattr needs to gain a pointer to "file"
so that the f_cred struct can be examined[1] (i.e. compare opener
against reader/writer).

[1] https://www.kernel.org/doc/html/latest/security/credentials.html#open-file-credentials

> +
> +		ilsm = lsm_task_ilsm(p);
> +		if (ilsm != LSMBLOB_INVALID)
> +			slot = ilsm;
> +		*value = kstrdup(lsm_slotlist[slot]->lsm, GFP_KERNEL);
> +		if (*value)
> +			return strlen(*value);
> +		return -ENOMEM;
> +	}
>  
>  	hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
>  		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
>  			continue;
> +		if (lsm == NULL && ilsm != LSMBLOB_INVALID &&
> +		    ilsm != hp->lsmid->slot)
> +			continue;
>  		return hp->hook.getprocattr(p, name, value);
>  	}
>  	return LSM_RET_DEFAULT(getprocattr);
>  }
>  
> +/**
> + * security_setprocattr - Set process attributes via /proc
> + * @lsm: name of module involved, or NULL
> + * @name: name of the attribute
> + * @value: value to set the attribute to
> + * @size: size of the value
> + *
> + * Set the process attribute for the specified security module
> + * to the specified value. Note that this can only be used to set
> + * the process attributes for the current, or "self" process.
> + * The /proc code has already done this check.
> + *
> + * Returns 0 on success, an appropriate code otherwise.
> + */
>  int security_setprocattr(const char *lsm, const char *name, void *value,
>  			 size_t size)
>  {
>  	struct security_hook_list *hp;
> +	char *termed;
> +	char *copy;
> +	int *ilsm = current->security;
> +	int rc = -EINVAL;
> +	int slot = 0;
> +
> +	if (!strcmp(name, "interface_lsm")) {
> +		/*
> +		 * Change the "interface_lsm" value only if all the security
> +		 * modules that support setting a procattr allow it.
> +		 * It is assumed that all such security modules will be
> +		 * cooperative.
> +		 */
> +		if (size == 0)
> +			return -EINVAL;
> +
> +		hlist_for_each_entry(hp, &security_hook_heads.setprocattr,
> +				     list) {
> +			rc = hp->hook.setprocattr(name, value, size);
> +			if (rc < 0)
> +				return rc;
> +		}

Similarly here -- how do the LSMs reason about who actually _opened_
this file?

-Kees

> +
> +		rc = -EINVAL;
> +
> +		copy = kmemdup_nul(value, size, GFP_KERNEL);
> +		if (copy == NULL)
> +			return -ENOMEM;
> +
> +		termed = strsep(&copy, " \n");
> +
> +		for (slot = 0; slot < lsm_slot; slot++)
> +			if (!strcmp(termed, lsm_slotlist[slot]->lsm)) {
> +				*ilsm = lsm_slotlist[slot]->slot;
> +				rc = size;
> +				break;
> +			}
> +
> +		kfree(termed);
> +		return rc;
> +	}
>  
>  	hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) {
>  		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
>  			continue;
> +		if (lsm == NULL && *ilsm != LSMBLOB_INVALID &&
> +		    *ilsm != hp->lsmid->slot)
> +			continue;
>  		return hp->hook.setprocattr(name, value, size);
>  	}
>  	return LSM_RET_DEFAULT(setprocattr);
> @@ -2207,15 +2326,15 @@ EXPORT_SYMBOL(security_ismaclabel);
>  int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen)
>  {
>  	struct security_hook_list *hp;
> -	int rc;
> +	int ilsm = lsm_task_ilsm(current);
>  
>  	hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
>  		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
>  			continue;
> -		rc = hp->hook.secid_to_secctx(blob->secid[hp->lsmid->slot],
> -					      secdata, seclen);
> -		if (rc != LSM_RET_DEFAULT(secid_to_secctx))
> -			return rc;
> +		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
> +			return hp->hook.secid_to_secctx(
> +					blob->secid[hp->lsmid->slot],
> +					secdata, seclen);
>  	}
>  
>  	return LSM_RET_DEFAULT(secid_to_secctx);
> @@ -2226,16 +2345,15 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
>  			     struct lsmblob *blob)
>  {
>  	struct security_hook_list *hp;
> -	int rc;
> +	int ilsm = lsm_task_ilsm(current);
>  
>  	lsmblob_init(blob, 0);
>  	hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) {
>  		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
>  			continue;
> -		rc = hp->hook.secctx_to_secid(secdata, seclen,
> -					      &blob->secid[hp->lsmid->slot]);
> -		if (rc != 0)
> -			return rc;
> +		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
> +			return hp->hook.secctx_to_secid(secdata, seclen,
> +						&blob->secid[hp->lsmid->slot]);
>  	}
>  	return 0;
>  }
> @@ -2243,7 +2361,14 @@ EXPORT_SYMBOL(security_secctx_to_secid);
>  
>  void security_release_secctx(char *secdata, u32 seclen)
>  {
> -	call_void_hook(release_secctx, secdata, seclen);
> +	struct security_hook_list *hp;
> +	int ilsm = lsm_task_ilsm(current);
> +
> +	hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list)
> +		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot) {
> +			hp->hook.release_secctx(secdata, seclen);
> +			return;
> +		}
>  }
>  EXPORT_SYMBOL(security_release_secctx);
>  
> @@ -2384,8 +2509,15 @@ EXPORT_SYMBOL(security_sock_rcv_skb);
>  int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
>  				      int __user *optlen, unsigned len)
>  {
> -	return call_int_hook(socket_getpeersec_stream, -ENOPROTOOPT, sock,
> -				optval, optlen, len);
> +	int ilsm = lsm_task_ilsm(current);
> +	struct security_hook_list *hp;
> +
> +	hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_stream,
> +			     list)
> +		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
> +			return hp->hook.socket_getpeersec_stream(sock, optval,
> +								 optlen, len);
> +	return -ENOPROTOOPT;
>  }
>  
>  int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 0133b142e938..dba867721336 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -6510,6 +6510,17 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
>  	/*
>  	 * Basic control over ability to set these attributes at all.
>  	 */
> +
> +	/*
> +	 * For setting interface_lsm, we only perform a permission check;
> +	 * the actual update to the interface_lsm value is handled by the
> +	 * LSM framework.
> +	 */
> +	if (!strcmp(name, "interface_lsm"))
> +		return avc_has_perm(&selinux_state,
> +				    mysid, mysid, SECCLASS_PROCESS2,
> +				    PROCESS2__SETDISPLAY, NULL);
> +
>  	if (!strcmp(name, "exec"))
>  		error = avc_has_perm(&selinux_state,
>  				     mysid, mysid, SECCLASS_PROCESS,
> diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
> index 62d19bccf3de..8f4b0dd6dd78 100644
> --- a/security/selinux/include/classmap.h
> +++ b/security/selinux/include/classmap.h
> @@ -53,7 +53,7 @@ struct security_class_mapping secclass_map[] = {
>  	    "execmem", "execstack", "execheap", "setkeycreate",
>  	    "setsockcreate", "getrlimit", NULL } },
>  	{ "process2",
> -	  { "nnp_transition", "nosuid_transition", NULL } },
> +	  { "nnp_transition", "nosuid_transition", "setdisplay", NULL } },
>  	{ "system",
>  	  { "ipc_info", "syslog_read", "syslog_mod",
>  	    "syslog_console", "module_request", "module_load", NULL } },
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index 5c10ad27be37..7aa7ea38f627 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -3508,6 +3508,13 @@ static int smack_setprocattr(const char *name, void *value, size_t size)
>  	struct smack_known_list_elem *sklep;
>  	int rc;
>  
> +	/*
> +	 * Allow the /proc/.../attr/current and SO_PEERSEC "interface_lsm"
> +	 * to be reset at will.
> +	 */
> +	if (strcmp(name, "interface_lsm") == 0)
> +		return 0;
> +
>  	if (!smack_privileged(CAP_MAC_ADMIN) && list_empty(&tsp->smk_relabel))
>  		return -EPERM;
>  
> -- 
> 2.29.2
> 

-- 
Kees Cook

Re: [PATCH v26 14/25] LSM: Specify which LSM to display

[Casey Schaufler]

On 5/14/2021 12:23 PM, Kees Cook wrote:
> On Thu, May 13, 2021 at 01:07:56PM -0700, Casey Schaufler wrote:
>> Create a new entry "interface_lsm" in the procfs attr directory for
>> controlling which LSM security information is displayed for a
>> process. A process can only read or write its own display value.
>>
>> The name of an active LSM that supplies hooks for
>> human readable data may be written to "interface_lsm" to set the
>> value. The name of the LSM currently in use can be read from
>> "interface_lsm". At this point there can only be one LSM capable
>> of display active. A helper function lsm_task_ilsm() is
>> provided to get the interface lsm slot for a task_struct.
>>
>> Setting the "interface_lsm" requires that all security modules using
>> setprocattr hooks allow the action. Each security module is
>> responsible for defining its policy.
>>
>> AppArmor hook provided by John Johansen <john.johansen@canonical.com>
>> SELinux hook provided by Stephen Smalley <stephen.smalley.work@gmail.com>
>>
>> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
>> Cc: Kees Cook <keescook@chromium.org>
>> Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
>> Cc: Paul Moore <paul@paul-moore.com>
>> Cc: John Johansen <john.johansen@canonical.com>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: linux-api@vger.kernel.org
>> Cc: linux-doc@vger.kernel.org
>> ---
>>  .../ABI/testing/procfs-attr-lsm_display       |  22 +++
>>  Documentation/security/lsm.rst                |  14 ++
>>  fs/proc/base.c                                |   1 +
>>  include/linux/lsm_hooks.h                     |  17 ++
>>  security/apparmor/include/apparmor.h          |   3 +-
>>  security/apparmor/lsm.c                       |  32 ++++
>>  security/security.c                           | 166 ++++++++++++++++--
>>  security/selinux/hooks.c                      |  11 ++
>>  security/selinux/include/classmap.h           |   2 +-
>>  security/smack/smack_lsm.c                    |   7 +
>>  10 files changed, 256 insertions(+), 19 deletions(-)
>>  create mode 100644 Documentation/ABI/testing/procfs-attr-lsm_display
>>
>> diff --git a/Documentation/ABI/testing/procfs-attr-lsm_display b/Documentation/ABI/testing/procfs-attr-lsm_display
>> new file mode 100644
>> index 000000000000..0f60005c235c
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/procfs-attr-lsm_display
>> @@ -0,0 +1,22 @@
>> +What:		/proc/*/attr/lsm_display
>> +Contact:	linux-security-module@vger.kernel.org,
>> +Description:	The name of the Linux security module (LSM) that will
>> +		provide information in the /proc/*/attr/current,
>> +		/proc/*/attr/prev and /proc/*/attr/exec interfaces.
>> +		The details of permissions required to read from
>> +		this interface are dependent on the LSMs active on the
>> +		system.
>> +		A process cannot write to this interface unless it
>> +		refers to itself.
>> +		The other details of permissions required to write to
>> +		this interface are dependent on the LSMs active on the
>> +		system.
>> +		The format of the data used by this interface is a
>> +		text string identifying the name of an LSM. The values
>> +		accepted are:
>> +			selinux		- the SELinux LSM
>> +			smack		- the Smack LSM
>> +			apparmor	- The AppArmor LSM
>> +		By convention the LSM names are lower case and do not
>> +		contain special characters.
>> +Users:		LSM user-space
>> diff --git a/Documentation/security/lsm.rst b/Documentation/security/lsm.rst
>> index 6a2a2e973080..b77b4a540391 100644
>> --- a/Documentation/security/lsm.rst
>> +++ b/Documentation/security/lsm.rst
>> @@ -129,3 +129,17 @@ to identify it as the first security module to be registered.
>>  The capabilities security module does not use the general security
>>  blobs, unlike other modules. The reasons are historical and are
>>  based on overhead, complexity and performance concerns.
>> +
>> +LSM External Interfaces
>> +=======================
>> +
>> +The LSM infrastructure does not generally provide external interfaces.
>> +The individual security modules provide what external interfaces they
>> +require.
>> +
>> +The file ``/sys/kernel/security/lsm`` provides a comma
>> +separated list of the active security modules.
>> +
>> +The file ``/proc/pid/attr/interface_lsm`` contains the name of the security
>> +module for which the ``/proc/pid/attr/current`` interface will
>> +apply. This interface can be written to.
>> diff --git a/fs/proc/base.c b/fs/proc/base.c
>> index 3851bfcdba56..10de522f3112 100644
>> --- a/fs/proc/base.c
>> +++ b/fs/proc/base.c
>> @@ -2807,6 +2807,7 @@ static const struct pid_entry attr_dir_stuff[] = {
>>  	ATTR(NULL, "fscreate",		0666),
>>  	ATTR(NULL, "keycreate",		0666),
>>  	ATTR(NULL, "sockcreate",	0666),
>> +	ATTR(NULL, "interface_lsm",	0666),
> Anyone can open this file... (continued below)
>
>>  #ifdef CONFIG_SECURITY_SMACK
>>  	DIR("smack",			0555,
>>  	    proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops),
>> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
>> index c61a16f0a5bc..d2c4bc94d47f 100644
>> --- a/include/linux/lsm_hooks.h
>> +++ b/include/linux/lsm_hooks.h
>> @@ -1686,4 +1686,21 @@ static inline void security_delete_hooks(struct security_hook_list *hooks,
>>  
>>  extern int lsm_inode_alloc(struct inode *inode);
>>  
>> +/**
>> + * lsm_task_ilsm - the "interface_lsm" for this task
>> + * @task: The task to report on
>> + *
>> + * Returns the task's interface LSM slot.
>> + */
>> +static inline int lsm_task_ilsm(struct task_struct *task)
>> +{
>> +#ifdef CONFIG_SECURITY
>> +	int *ilsm = task->security;
>> +
>> +	if (ilsm)
>> +		return *ilsm;
>> +#endif
>> +	return LSMBLOB_INVALID;
>> +}
>> +
>>  #endif /* ! __LINUX_LSM_HOOKS_H */
>> diff --git a/security/apparmor/include/apparmor.h b/security/apparmor/include/apparmor.h
>> index 1fbabdb565a8..b1622fcb4394 100644
>> --- a/security/apparmor/include/apparmor.h
>> +++ b/security/apparmor/include/apparmor.h
>> @@ -28,8 +28,9 @@
>>  #define AA_CLASS_SIGNAL		10
>>  #define AA_CLASS_NET		14
>>  #define AA_CLASS_LABEL		16
>> +#define AA_CLASS_DISPLAY_LSM	17
>>  
>> -#define AA_CLASS_LAST		AA_CLASS_LABEL
>> +#define AA_CLASS_LAST		AA_CLASS_DISPLAY_LSM
>>  
>>  /* Control parameters settable through module/boot flags */
>>  extern enum audit_mode aa_g_audit;
>> diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
>> index 392e25940d1f..4237536106aa 100644
>> --- a/security/apparmor/lsm.c
>> +++ b/security/apparmor/lsm.c
>> @@ -621,6 +621,25 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
>>  	return error;
>>  }
>>  
>> +
>> +static int profile_interface_lsm(struct aa_profile *profile,
>> +				 struct common_audit_data *sa)
>> +{
>> +	struct aa_perms perms = { };
>> +	unsigned int state;
>> +
>> +	state = PROFILE_MEDIATES(profile, AA_CLASS_DISPLAY_LSM);
>> +	if (state) {
>> +		aa_compute_perms(profile->policy.dfa, state, &perms);
>> +		aa_apply_modes_to_perms(profile, &perms);
>> +		aad(sa)->label = &profile->label;
>> +
>> +		return aa_check_perms(profile, &perms, AA_MAY_WRITE, sa, NULL);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>  static int apparmor_setprocattr(const char *name, void *value,
>>  				size_t size)
>>  {
>> @@ -632,6 +651,19 @@ static int apparmor_setprocattr(const char *name, void *value,
>>  	if (size == 0)
>>  		return -EINVAL;
>>  
>> +	/* LSM infrastructure does actual setting of interface_lsm if allowed */
>> +	if (!strcmp(name, "interface_lsm")) {
>> +		struct aa_profile *profile;
>> +		struct aa_label *label;
>> +
>> +		aad(&sa)->info = "set interface lsm";
>> +		label = begin_current_label_crit_section();
>> +		error = fn_for_each_confined(label, profile,
>> +					profile_interface_lsm(profile, &sa));
>> +		end_current_label_crit_section(label);
>> +		return error;
>> +	}
>> +
>>  	/* AppArmor requires that the buffer must be null terminated atm */
>>  	if (args[size - 1] != '\0') {
>>  		/* null terminate */
>> diff --git a/security/security.c b/security/security.c
>> index f5407a85641e..1ce125c01782 100644
>> --- a/security/security.c
>> +++ b/security/security.c
>> @@ -77,7 +77,16 @@ static struct kmem_cache *lsm_file_cache;
>>  static struct kmem_cache *lsm_inode_cache;
>>  
>>  char *lsm_names;
>> -static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init;
>> +
>> +/*
>> + * The task blob includes the "interface_lsm" slot used for
>> + * chosing which module presents contexts.
>> + * Using a long to avoid potential alignment issues with
>> + * module assigned task blobs.
>> + */
>> +static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init = {
>> +	.lbs_task = sizeof(long),
>> +};
>>  
>>  /* Boot-time LSM user choice */
>>  static __initdata const char *chosen_lsm_order;
>> @@ -669,6 +678,8 @@ int lsm_inode_alloc(struct inode *inode)
>>   */
>>  static int lsm_task_alloc(struct task_struct *task)
>>  {
>> +	int *ilsm;
>> +
>>  	if (blob_sizes.lbs_task == 0) {
>>  		task->security = NULL;
>>  		return 0;
>> @@ -677,6 +688,15 @@ static int lsm_task_alloc(struct task_struct *task)
>>  	task->security = kzalloc(blob_sizes.lbs_task, GFP_KERNEL);
>>  	if (task->security == NULL)
>>  		return -ENOMEM;
>> +
>> +	/*
>> +	 * The start of the task blob contains the "interface" LSM slot number.
>> +	 * Start with it set to the invalid slot number, indicating that the
>> +	 * default first registered LSM be displayed.
>> +	 */
>> +	ilsm = task->security;
>> +	*ilsm = LSMBLOB_INVALID;
>> +
>>  	return 0;
>>  }
>>  
>> @@ -1732,14 +1752,26 @@ int security_file_open(struct file *file)
>>  
>>  int security_task_alloc(struct task_struct *task, unsigned long clone_flags)
>>  {
>> +	int *oilsm = current->security;
>> +	int *nilsm;
>>  	int rc = lsm_task_alloc(task);
>>  
>> -	if (rc)
>> +	if (unlikely(rc))
>>  		return rc;
>> +
>>  	rc = call_int_hook(task_alloc, 0, task, clone_flags);
>> -	if (unlikely(rc))
>> +	if (unlikely(rc)) {
>>  		security_task_free(task);
>> -	return rc;
>> +		return rc;
>> +	}
>> +
>> +	if (oilsm) {
>> +		nilsm = task->security;
>> +		if (nilsm)
>> +			*nilsm = *oilsm;
>> +	}
>> +
>> +	return 0;
>>  }
>>  
>>  void security_task_free(struct task_struct *task)
>> @@ -2171,23 +2203,110 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
>>  				char **value)
>>  {
>>  	struct security_hook_list *hp;
>> +	int ilsm = lsm_task_ilsm(current);
>> +	int slot = 0;
>> +
>> +	if (!strcmp(name, "interface_lsm")) {
>> +		/*
>> +		 * lsm_slot will be 0 if there are no displaying modules.
>> +		 */
>> +		if (lsm_slot == 0)
>> +			return -EINVAL;
>> +
>> +		/*
>> +		 * Only allow getting the current process' interface_lsm.
>> +		 * There are too few reasons to get another process'
>> +		 * interface_lsm and too many LSM policy issues.
>> +		 */
>> +		if (current != p)
>> +			return -EINVAL;
> ... but context isn't established by just checking "current", as this
> file handle may have been given to another process.
>
> I suspect the security_get/setprocattr needs to gain a pointer to "file"
> so that the f_cred struct can be examined[1] (i.e. compare opener
> against reader/writer).
>
> [1] https://www.kernel.org/doc/html/latest/security/credentials.html#open-file-credentials

It's not credentials being checked here. The check is whether the task that
would be affected is "current". Process A can't open /proc/B/attr/interface_lsm
with write access. The only process that can open it for write access is B.
If process B opens /proc/B/attr/interface_lsm for write access it could send
the file handle to process A, but process A can't write to the file because
(current != p) that is, (A != B).

>> +
>> +		ilsm = lsm_task_ilsm(p);
>> +		if (ilsm != LSMBLOB_INVALID)
>> +			slot = ilsm;
>> +		*value = kstrdup(lsm_slotlist[slot]->lsm, GFP_KERNEL);
>> +		if (*value)
>> +			return strlen(*value);
>> +		return -ENOMEM;
>> +	}
>>  
>>  	hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
>>  		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
>>  			continue;
>> +		if (lsm == NULL && ilsm != LSMBLOB_INVALID &&
>> +		    ilsm != hp->lsmid->slot)
>> +			continue;
>>  		return hp->hook.getprocattr(p, name, value);
>>  	}
>>  	return LSM_RET_DEFAULT(getprocattr);
>>  }
>>  
>> +/**
>> + * security_setprocattr - Set process attributes via /proc
>> + * @lsm: name of module involved, or NULL
>> + * @name: name of the attribute
>> + * @value: value to set the attribute to
>> + * @size: size of the value
>> + *
>> + * Set the process attribute for the specified security module
>> + * to the specified value. Note that this can only be used to set
>> + * the process attributes for the current, or "self" process.
>> + * The /proc code has already done this check.
>> + *
>> + * Returns 0 on success, an appropriate code otherwise.
>> + */
>>  int security_setprocattr(const char *lsm, const char *name, void *value,
>>  			 size_t size)
>>  {
>>  	struct security_hook_list *hp;
>> +	char *termed;
>> +	char *copy;
>> +	int *ilsm = current->security;
>> +	int rc = -EINVAL;
>> +	int slot = 0;
>> +
>> +	if (!strcmp(name, "interface_lsm")) {
>> +		/*
>> +		 * Change the "interface_lsm" value only if all the security
>> +		 * modules that support setting a procattr allow it.
>> +		 * It is assumed that all such security modules will be
>> +		 * cooperative.
>> +		 */
>> +		if (size == 0)
>> +			return -EINVAL;
>> +
>> +		hlist_for_each_entry(hp, &security_hook_heads.setprocattr,
>> +				     list) {
>> +			rc = hp->hook.setprocattr(name, value, size);
>> +			if (rc < 0)
>> +				return rc;
>> +		}
> Similarly here -- how do the LSMs reason about who actually _opened_
> this file?
>
> -Kees
>
>> +
>> +		rc = -EINVAL;
>> +
>> +		copy = kmemdup_nul(value, size, GFP_KERNEL);
>> +		if (copy == NULL)
>> +			return -ENOMEM;
>> +
>> +		termed = strsep(&copy, " \n");
>> +
>> +		for (slot = 0; slot < lsm_slot; slot++)
>> +			if (!strcmp(termed, lsm_slotlist[slot]->lsm)) {
>> +				*ilsm = lsm_slotlist[slot]->slot;
>> +				rc = size;
>> +				break;
>> +			}
>> +
>> +		kfree(termed);
>> +		return rc;
>> +	}
>>  
>>  	hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) {
>>  		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
>>  			continue;
>> +		if (lsm == NULL && *ilsm != LSMBLOB_INVALID &&
>> +		    *ilsm != hp->lsmid->slot)
>> +			continue;
>>  		return hp->hook.setprocattr(name, value, size);
>>  	}
>>  	return LSM_RET_DEFAULT(setprocattr);
>> @@ -2207,15 +2326,15 @@ EXPORT_SYMBOL(security_ismaclabel);
>>  int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen)
>>  {
>>  	struct security_hook_list *hp;
>> -	int rc;
>> +	int ilsm = lsm_task_ilsm(current);
>>  
>>  	hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
>>  		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
>>  			continue;
>> -		rc = hp->hook.secid_to_secctx(blob->secid[hp->lsmid->slot],
>> -					      secdata, seclen);
>> -		if (rc != LSM_RET_DEFAULT(secid_to_secctx))
>> -			return rc;
>> +		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
>> +			return hp->hook.secid_to_secctx(
>> +					blob->secid[hp->lsmid->slot],
>> +					secdata, seclen);
>>  	}
>>  
>>  	return LSM_RET_DEFAULT(secid_to_secctx);
>> @@ -2226,16 +2345,15 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
>>  			     struct lsmblob *blob)
>>  {
>>  	struct security_hook_list *hp;
>> -	int rc;
>> +	int ilsm = lsm_task_ilsm(current);
>>  
>>  	lsmblob_init(blob, 0);
>>  	hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) {
>>  		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
>>  			continue;
>> -		rc = hp->hook.secctx_to_secid(secdata, seclen,
>> -					      &blob->secid[hp->lsmid->slot]);
>> -		if (rc != 0)
>> -			return rc;
>> +		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
>> +			return hp->hook.secctx_to_secid(secdata, seclen,
>> +						&blob->secid[hp->lsmid->slot]);
>>  	}
>>  	return 0;
>>  }
>> @@ -2243,7 +2361,14 @@ EXPORT_SYMBOL(security_secctx_to_secid);
>>  
>>  void security_release_secctx(char *secdata, u32 seclen)
>>  {
>> -	call_void_hook(release_secctx, secdata, seclen);
>> +	struct security_hook_list *hp;
>> +	int ilsm = lsm_task_ilsm(current);
>> +
>> +	hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list)
>> +		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot) {
>> +			hp->hook.release_secctx(secdata, seclen);
>> +			return;
>> +		}
>>  }
>>  EXPORT_SYMBOL(security_release_secctx);
>>  
>> @@ -2384,8 +2509,15 @@ EXPORT_SYMBOL(security_sock_rcv_skb);
>>  int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
>>  				      int __user *optlen, unsigned len)
>>  {
>> -	return call_int_hook(socket_getpeersec_stream, -ENOPROTOOPT, sock,
>> -				optval, optlen, len);
>> +	int ilsm = lsm_task_ilsm(current);
>> +	struct security_hook_list *hp;
>> +
>> +	hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_stream,
>> +			     list)
>> +		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
>> +			return hp->hook.socket_getpeersec_stream(sock, optval,
>> +								 optlen, len);
>> +	return -ENOPROTOOPT;
>>  }
>>  
>>  int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
>> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
>> index 0133b142e938..dba867721336 100644
>> --- a/security/selinux/hooks.c
>> +++ b/security/selinux/hooks.c
>> @@ -6510,6 +6510,17 @@ static int selinux_setprocattr(const char *name, void *value, size_t size)
>>  	/*
>>  	 * Basic control over ability to set these attributes at all.
>>  	 */
>> +
>> +	/*
>> +	 * For setting interface_lsm, we only perform a permission check;
>> +	 * the actual update to the interface_lsm value is handled by the
>> +	 * LSM framework.
>> +	 */
>> +	if (!strcmp(name, "interface_lsm"))
>> +		return avc_has_perm(&selinux_state,
>> +				    mysid, mysid, SECCLASS_PROCESS2,
>> +				    PROCESS2__SETDISPLAY, NULL);
>> +
>>  	if (!strcmp(name, "exec"))
>>  		error = avc_has_perm(&selinux_state,
>>  				     mysid, mysid, SECCLASS_PROCESS,
>> diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
>> index 62d19bccf3de..8f4b0dd6dd78 100644
>> --- a/security/selinux/include/classmap.h
>> +++ b/security/selinux/include/classmap.h
>> @@ -53,7 +53,7 @@ struct security_class_mapping secclass_map[] = {
>>  	    "execmem", "execstack", "execheap", "setkeycreate",
>>  	    "setsockcreate", "getrlimit", NULL } },
>>  	{ "process2",
>> -	  { "nnp_transition", "nosuid_transition", NULL } },
>> +	  { "nnp_transition", "nosuid_transition", "setdisplay", NULL } },
>>  	{ "system",
>>  	  { "ipc_info", "syslog_read", "syslog_mod",
>>  	    "syslog_console", "module_request", "module_load", NULL } },
>> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
>> index 5c10ad27be37..7aa7ea38f627 100644
>> --- a/security/smack/smack_lsm.c
>> +++ b/security/smack/smack_lsm.c
>> @@ -3508,6 +3508,13 @@ static int smack_setprocattr(const char *name, void *value, size_t size)
>>  	struct smack_known_list_elem *sklep;
>>  	int rc;
>>  
>> +	/*
>> +	 * Allow the /proc/.../attr/current and SO_PEERSEC "interface_lsm"
>> +	 * to be reset at will.
>> +	 */
>> +	if (strcmp(name, "interface_lsm") == 0)
>> +		return 0;
>> +
>>  	if (!smack_privileged(CAP_MAC_ADMIN) && list_empty(&tsp->smk_relabel))
>>  		return -EPERM;
>>  
>> -- 
>> 2.29.2
>>

Re: [PATCH v26 14/25] LSM: Specify which LSM to display

[Paul Moore]

On Mon, May 17, 2021 at 3:53 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
> On 5/14/2021 12:23 PM, Kees Cook wrote:
> > On Thu, May 13, 2021 at 01:07:56PM -0700, Casey Schaufler wrote:
> >> Create a new entry "interface_lsm" in the procfs attr directory for
> >> controlling which LSM security information is displayed for a
> >> process. A process can only read or write its own display value.
> >>
> >> The name of an active LSM that supplies hooks for
> >> human readable data may be written to "interface_lsm" to set the
> >> value. The name of the LSM currently in use can be read from
> >> "interface_lsm". At this point there can only be one LSM capable
> >> of display active. A helper function lsm_task_ilsm() is
> >> provided to get the interface lsm slot for a task_struct.
> >>
> >> Setting the "interface_lsm" requires that all security modules using
> >> setprocattr hooks allow the action. Each security module is
> >> responsible for defining its policy.
> >>
> >> AppArmor hook provided by John Johansen <john.johansen@canonical.com>
> >> SELinux hook provided by Stephen Smalley <stephen.smalley.work@gmail.com>
> >>
> >> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> >> Cc: Kees Cook <keescook@chromium.org>
> >> Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
> >> Cc: Paul Moore <paul@paul-moore.com>
> >> Cc: John Johansen <john.johansen@canonical.com>
> >> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> >> Cc: linux-api@vger.kernel.org
> >> Cc: linux-doc@vger.kernel.org
> >> ---
> >>  .../ABI/testing/procfs-attr-lsm_display       |  22 +++
> >>  Documentation/security/lsm.rst                |  14 ++
> >>  fs/proc/base.c                                |   1 +
> >>  include/linux/lsm_hooks.h                     |  17 ++
> >>  security/apparmor/include/apparmor.h          |   3 +-
> >>  security/apparmor/lsm.c                       |  32 ++++
> >>  security/security.c                           | 166 ++++++++++++++++--
> >>  security/selinux/hooks.c                      |  11 ++
> >>  security/selinux/include/classmap.h           |   2 +-
> >>  security/smack/smack_lsm.c                    |   7 +
> >>  10 files changed, 256 insertions(+), 19 deletions(-)
> >>  create mode 100644 Documentation/ABI/testing/procfs-attr-lsm_display

...

> >> @@ -2171,23 +2203,110 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
> >>                              char **value)
> >>  {
> >>      struct security_hook_list *hp;
> >> +    int ilsm = lsm_task_ilsm(current);
> >> +    int slot = 0;
> >> +
> >> +    if (!strcmp(name, "interface_lsm")) {
> >> +            /*
> >> +             * lsm_slot will be 0 if there are no displaying modules.
> >> +             */
> >> +            if (lsm_slot == 0)
> >> +                    return -EINVAL;
> >> +
> >> +            /*
> >> +             * Only allow getting the current process' interface_lsm.
> >> +             * There are too few reasons to get another process'
> >> +             * interface_lsm and too many LSM policy issues.
> >> +             */
> >> +            if (current != p)
> >> +                    return -EINVAL;
> > ... but context isn't established by just checking "current", as this
> > file handle may have been given to another process.
> >
> > I suspect the security_get/setprocattr needs to gain a pointer to "file"
> > so that the f_cred struct can be examined[1] (i.e. compare opener
> > against reader/writer).
> >
> > [1] https://www.kernel.org/doc/html/latest/security/credentials.html#open-file-credentials
>
> It's not credentials being checked here. The check is whether the task that
> would be affected is "current". Process A can't open /proc/B/attr/interface_lsm
> with write access. The only process that can open it for write access is B.
> If process B opens /proc/B/attr/interface_lsm for write access it could send
> the file handle to process A, but process A can't write to the file because
> (current != p) that is, (A != B).

Agreed.

Acked-by: Paul Moore <paul@paul-moore.com>


--
paul moore
www.paul-moore.com

[PATCH v26 15/25] LSM: Ensure the correct LSM context releaser

[Casey Schaufler]

Add a new lsmcontext data structure to hold all the information
about a "security context", including the string, its size and
which LSM allocated the string. The allocation information is
necessary because LSMs have different policies regarding the
lifecycle of these strings. SELinux allocates and destroys
them on each use, whereas Smack provides a pointer to an entry
in a list that never goes away.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-integrity@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-audit@redhat.com
Cc: netfilter-devel@vger.kernel.org
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: linux-nfs@vger.kernel.org
---
 drivers/android/binder.c                | 10 ++++---
 fs/ceph/xattr.c                         |  6 ++++-
 fs/nfs/nfs4proc.c                       |  8 ++++--
 fs/nfsd/nfs4xdr.c                       |  7 +++--
 include/linux/security.h                | 35 +++++++++++++++++++++++--
 include/net/scm.h                       |  5 +++-
 kernel/audit.c                          | 14 +++++++---
 kernel/auditsc.c                        | 12 ++++++---
 net/ipv4/ip_sockglue.c                  |  4 ++-
 net/netfilter/nf_conntrack_netlink.c    |  4 ++-
 net/netfilter/nf_conntrack_standalone.c |  4 ++-
 net/netfilter/nfnetlink_queue.c         | 13 ++++++---
 net/netlabel/netlabel_unlabeled.c       | 19 +++++++++++---
 net/netlabel/netlabel_user.c            |  4 ++-
 security/security.c                     | 11 ++++----
 15 files changed, 121 insertions(+), 35 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index ab55358f868b..eca789340ef6 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2461,6 +2461,7 @@ static void binder_transaction(struct binder_proc *proc,
 	int t_debug_id = atomic_inc_return(&binder_last_id);
 	char *secctx = NULL;
 	u32 secctx_sz = 0;
+	struct lsmcontext scaff; /* scaffolding */
 
 	e = binder_transaction_log_add(&binder_transaction_log);
 	e->debug_id = t_debug_id;
@@ -2772,7 +2773,8 @@ static void binder_transaction(struct binder_proc *proc,
 			t->security_ctx = 0;
 			WARN_ON(1);
 		}
-		security_release_secctx(secctx, secctx_sz);
+		lsmcontext_init(&scaff, secctx, secctx_sz, 0);
+		security_release_secctx(&scaff);
 		secctx = NULL;
 	}
 	t->buffer->debug_id = t->debug_id;
@@ -3114,8 +3116,10 @@ static void binder_transaction(struct binder_proc *proc,
 	binder_alloc_free_buf(&target_proc->alloc, t->buffer);
 err_binder_alloc_buf_failed:
 err_bad_extra_size:
-	if (secctx)
-		security_release_secctx(secctx, secctx_sz);
+	if (secctx) {
+		lsmcontext_init(&scaff, secctx, secctx_sz, 0);
+		security_release_secctx(&scaff);
+	}
 err_get_secctx_failed:
 	kfree(tcomplete);
 	binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 1242db8d3444..b867089e1aa4 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -1356,12 +1356,16 @@ int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
 
 void ceph_release_acl_sec_ctx(struct ceph_acl_sec_ctx *as_ctx)
 {
+#ifdef CONFIG_CEPH_FS_SECURITY_LABEL
+	struct lsmcontext scaff; /* scaffolding */
+#endif
 #ifdef CONFIG_CEPH_FS_POSIX_ACL
 	posix_acl_release(as_ctx->acl);
 	posix_acl_release(as_ctx->default_acl);
 #endif
 #ifdef CONFIG_CEPH_FS_SECURITY_LABEL
-	security_release_secctx(as_ctx->sec_ctx, as_ctx->sec_ctxlen);
+	lsmcontext_init(&scaff, as_ctx->sec_ctx, as_ctx->sec_ctxlen, 0);
+	security_release_secctx(&scaff);
 #endif
 	if (as_ctx->pagelist)
 		ceph_pagelist_release(as_ctx->pagelist);
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 87d04f2c9385..a179d70eeb7e 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -136,8 +136,12 @@ nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
 static inline void
 nfs4_label_release_security(struct nfs4_label *label)
 {
-	if (label)
-		security_release_secctx(label->label, label->len);
+	struct lsmcontext scaff; /* scaffolding */
+
+	if (label) {
+		lsmcontext_init(&scaff, label->label, label->len, 0);
+		security_release_secctx(&scaff);
+	}
 }
 static inline u32 *nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label)
 {
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 7abeccb975b2..089ec4b61ef1 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2844,6 +2844,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	int err;
 	struct nfs4_acl *acl = NULL;
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
+	struct lsmcontext scaff; /* scaffolding */
 	void *context = NULL;
 	int contextlen;
 #endif
@@ -3345,8 +3346,10 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 
 out:
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
-	if (context)
-		security_release_secctx(context, contextlen);
+	if (context) {
+		lsmcontext_init(&scaff, context, contextlen, 0); /*scaffolding*/
+		security_release_secctx(&scaff);
+	}
 #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
 	kfree(acl);
 	if (tempfh) {
diff --git a/include/linux/security.h b/include/linux/security.h
index c1c31eb23859..3b2ffef65b05 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -133,6 +133,37 @@ enum lockdown_reason {
 
 extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1];
 
+/*
+ * A "security context" is the text representation of
+ * the information used by LSMs.
+ * This structure contains the string, its length, and which LSM
+ * it is useful for.
+ */
+struct lsmcontext {
+	char	*context;	/* Provided by the module */
+	u32	len;
+	int	slot;		/* Identifies the module */
+};
+
+/**
+ * lsmcontext_init - initialize an lsmcontext structure.
+ * @cp: Pointer to the context to initialize
+ * @context: Initial context, or NULL
+ * @size: Size of context, or 0
+ * @slot: Which LSM provided the context
+ *
+ * Fill in the lsmcontext from the provided information.
+ * This is a scaffolding function that will be removed when
+ * lsmcontext integration is complete.
+ */
+static inline void lsmcontext_init(struct lsmcontext *cp, char *context,
+				   u32 size, int slot)
+{
+	cp->slot = slot;
+	cp->context = context;
+	cp->len = size;
+}
+
 /*
  * Data exported by the security modules
  *
@@ -550,7 +581,7 @@ int security_ismaclabel(const char *name);
 int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen);
 int security_secctx_to_secid(const char *secdata, u32 seclen,
 			     struct lsmblob *blob);
-void security_release_secctx(char *secdata, u32 seclen);
+void security_release_secctx(struct lsmcontext *cp);
 void security_inode_invalidate_secctx(struct inode *inode);
 int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
 int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);
@@ -1414,7 +1445,7 @@ static inline int security_secctx_to_secid(const char *secdata,
 	return -EOPNOTSUPP;
 }
 
-static inline void security_release_secctx(char *secdata, u32 seclen)
+static inline void security_release_secctx(struct lsmcontext *cp)
 {
 }
 
diff --git a/include/net/scm.h b/include/net/scm.h
index 23a35ff1b3f2..f273c4d777ec 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -92,6 +92,7 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
 #ifdef CONFIG_SECURITY_NETWORK
 static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
 {
+	struct lsmcontext context;
 	struct lsmblob lb;
 	char *secdata;
 	u32 seclen;
@@ -106,7 +107,9 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
 
 		if (!err) {
 			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
-			security_release_secctx(secdata, seclen);
+			/*scaffolding*/
+			lsmcontext_init(&context, secdata, seclen, 0);
+			security_release_secctx(&context);
 		}
 	}
 }
diff --git a/kernel/audit.c b/kernel/audit.c
index 8ec64e6e8bc0..c17ec23158c4 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1192,6 +1192,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	struct audit_sig_info   *sig_data;
 	char			*ctx = NULL;
 	u32			len;
+	struct lsmcontext	scaff; /* scaffolding */
 
 	err = audit_netlink_ok(skb, msg_type);
 	if (err)
@@ -1449,15 +1450,18 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		}
 		sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
 		if (!sig_data) {
-			if (lsmblob_is_set(&audit_sig_lsm))
-				security_release_secctx(ctx, len);
+			if (lsmblob_is_set(&audit_sig_lsm)) {
+				lsmcontext_init(&scaff, ctx, len, 0);
+				security_release_secctx(&scaff);
+			}
 			return -ENOMEM;
 		}
 		sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
 		sig_data->pid = audit_sig_pid;
 		if (lsmblob_is_set(&audit_sig_lsm)) {
 			memcpy(sig_data->ctx, ctx, len);
-			security_release_secctx(ctx, len);
+			lsmcontext_init(&scaff, ctx, len, 0);
+			security_release_secctx(&scaff);
 		}
 		audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
 				 sig_data, sizeof(*sig_data) + len);
@@ -2132,6 +2136,7 @@ int audit_log_task_context(struct audit_buffer *ab)
 	unsigned len;
 	int error;
 	struct lsmblob blob;
+	struct lsmcontext scaff; /* scaffolding */
 
 	security_task_getsecid_subj(current, &blob);
 	if (!lsmblob_is_set(&blob))
@@ -2145,7 +2150,8 @@ int audit_log_task_context(struct audit_buffer *ab)
 	}
 
 	audit_log_format(ab, " subj=%s", ctx);
-	security_release_secctx(ctx, len);
+	lsmcontext_init(&scaff, ctx, len, 0);
+	security_release_secctx(&scaff);
 	return 0;
 
 error_path:
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 573c6a8e505f..3fb9d3639123 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -996,6 +996,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 				 struct lsmblob *blob, char *comm)
 {
 	struct audit_buffer *ab;
+	struct lsmcontext lsmcxt;
 	char *ctx = NULL;
 	u32 len;
 	int rc = 0;
@@ -1013,7 +1014,8 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 			rc = 1;
 		} else {
 			audit_log_format(ab, " obj=%s", ctx);
-			security_release_secctx(ctx, len);
+			lsmcontext_init(&lsmcxt, ctx, len, 0); /*scaffolding*/
+			security_release_secctx(&lsmcxt);
 		}
 	}
 	audit_log_format(ab, " ocomm=");
@@ -1226,6 +1228,7 @@ static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
 
 static void show_special(struct audit_context *context, int *call_panic)
 {
+	struct lsmcontext lsmcxt;
 	struct audit_buffer *ab;
 	int i;
 
@@ -1259,7 +1262,8 @@ static void show_special(struct audit_context *context, int *call_panic)
 				*call_panic = 1;
 			} else {
 				audit_log_format(ab, " obj=%s", ctx);
-				security_release_secctx(ctx, len);
+				lsmcontext_init(&lsmcxt, ctx, len, 0);
+				security_release_secctx(&lsmcxt);
 			}
 		}
 		if (context->ipc.has_perm) {
@@ -1408,6 +1412,7 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 		char *ctx = NULL;
 		u32 len;
 		struct lsmblob blob;
+		struct lsmcontext lsmcxt;
 
 		lsmblob_init(&blob, n->osid);
 		if (security_secid_to_secctx(&blob, &ctx, &len)) {
@@ -1416,7 +1421,8 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 				*call_panic = 2;
 		} else {
 			audit_log_format(ab, " obj=%s", ctx);
-			security_release_secctx(ctx, len);
+			lsmcontext_init(&lsmcxt, ctx, len, 0); /* scaffolding */
+			security_release_secctx(&lsmcxt);
 		}
 	}
 
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 2f089733ada7..a7e4c1b34b6c 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -130,6 +130,7 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
 
 static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 {
+	struct lsmcontext context;
 	struct lsmblob lb;
 	char *secdata;
 	u32 seclen, secid;
@@ -145,7 +146,8 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 		return;
 
 	put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata);
-	security_release_secctx(secdata, seclen);
+	lsmcontext_init(&context, secdata, seclen, 0); /* scaffolding */
+	security_release_secctx(&context);
 }
 
 static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index caf3ecb5a66b..914ab6a96573 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -339,6 +339,7 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	int len, ret;
 	char *secctx;
 	struct lsmblob blob;
+	struct lsmcontext context;
 
 	/* lsmblob_init() puts ct->secmark into all of the secids in blob.
 	 * security_secid_to_secctx() will know which security module
@@ -359,7 +360,8 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 
 	ret = 0;
 nla_put_failure:
-	security_release_secctx(secctx, len);
+	lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
+	security_release_secctx(&context);
 	return ret;
 }
 #else
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index b02afa0a1516..b039445f3efc 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -176,6 +176,7 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 	u32 len;
 	char *secctx;
 	struct lsmblob blob;
+	struct lsmcontext context;
 
 	lsmblob_init(&blob, ct->secmark);
 	ret = security_secid_to_secctx(&blob, &secctx, &len);
@@ -184,7 +185,8 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 
 	seq_printf(s, "secctx=%s ", secctx);
 
-	security_release_secctx(secctx, len);
+	lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
+	security_release_secctx(&context);
 }
 #else
 static inline void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index bdbb0b60bf7b..06b7751c7668 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -397,6 +397,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	enum ip_conntrack_info ctinfo;
 	struct nfnl_ct_hook *nfnl_ct;
 	bool csum_verify;
+	struct lsmcontext scaff; /* scaffolding */
 	char *secdata = NULL;
 	u32 seclen = 0;
 
@@ -626,8 +627,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	}
 
 	nlh->nlmsg_len = skb->len;
-	if (seclen)
-		security_release_secctx(secdata, seclen);
+	if (seclen) {
+		lsmcontext_init(&scaff, secdata, seclen, 0);
+		security_release_secctx(&scaff);
+	}
 	return skb;
 
 nla_put_failure:
@@ -635,8 +638,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	kfree_skb(skb);
 	net_err_ratelimited("nf_queue: error creating packet message\n");
 nlmsg_failure:
-	if (seclen)
-		security_release_secctx(secdata, seclen);
+	if (seclen) {
+		lsmcontext_init(&scaff, secdata, seclen, 0);
+		security_release_secctx(&scaff);
+	}
 	return NULL;
 }
 
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index b08442582874..8ca1e2b33dcf 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -374,6 +374,7 @@ int netlbl_unlhsh_add(struct net *net,
 	struct net_device *dev;
 	struct netlbl_unlhsh_iface *iface;
 	struct audit_buffer *audit_buf = NULL;
+	struct lsmcontext context;
 	char *secctx = NULL;
 	u32 secctx_len;
 	struct lsmblob blob;
@@ -447,7 +448,9 @@ int netlbl_unlhsh_add(struct net *net,
 					     &secctx,
 					     &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			security_release_secctx(secctx, secctx_len);
+			/* scaffolding */
+			lsmcontext_init(&context, secctx, secctx_len, 0);
+			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0);
 		audit_log_end(audit_buf);
@@ -478,6 +481,7 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 	struct netlbl_unlhsh_addr4 *entry;
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
+	struct lsmcontext context;
 	char *secctx;
 	u32 secctx_len;
 	struct lsmblob blob;
@@ -509,7 +513,9 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 		    security_secid_to_secctx(&blob,
 					     &secctx, &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			security_release_secctx(secctx, secctx_len);
+			/* scaffolding */
+			lsmcontext_init(&context, secctx, secctx_len, 0);
+			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
 		audit_log_end(audit_buf);
@@ -546,6 +552,7 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 	struct netlbl_unlhsh_addr6 *entry;
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
+	struct lsmcontext context;
 	char *secctx;
 	u32 secctx_len;
 	struct lsmblob blob;
@@ -576,7 +583,8 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 		    security_secid_to_secctx(&blob,
 					     &secctx, &secctx_len) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			security_release_secctx(secctx, secctx_len);
+			lsmcontext_init(&context, secctx, secctx_len, 0);
+			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
 		audit_log_end(audit_buf);
@@ -1095,6 +1103,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 	int ret_val = -ENOMEM;
 	struct netlbl_unlhsh_walk_arg *cb_arg = arg;
 	struct net_device *dev;
+	struct lsmcontext context;
 	void *data;
 	u32 secid;
 	char *secctx;
@@ -1165,7 +1174,9 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 			  NLBL_UNLABEL_A_SECCTX,
 			  secctx_len,
 			  secctx);
-	security_release_secctx(secctx, secctx_len);
+	/* scaffolding */
+	lsmcontext_init(&context, secctx, secctx_len, 0);
+	security_release_secctx(&context);
 	if (ret_val != 0)
 		goto list_cb_failure;
 
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 893301ae0131..ef139d8ae7cd 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -84,6 +84,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 					       struct netlbl_audit *audit_info)
 {
 	struct audit_buffer *audit_buf;
+	struct lsmcontext context;
 	char *secctx;
 	u32 secctx_len;
 	struct lsmblob blob;
@@ -103,7 +104,8 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 	if (audit_info->secid != 0 &&
 	    security_secid_to_secctx(&blob, &secctx, &secctx_len) == 0) {
 		audit_log_format(audit_buf, " subj=%s", secctx);
-		security_release_secctx(secctx, secctx_len);
+		lsmcontext_init(&context, secctx, secctx_len, 0);/*scaffolding*/
+		security_release_secctx(&context);
 	}
 
 	return audit_buf;
diff --git a/security/security.c b/security/security.c
index 1ce125c01782..f6a33bf2a7fc 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2359,16 +2359,17 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
 }
 EXPORT_SYMBOL(security_secctx_to_secid);
 
-void security_release_secctx(char *secdata, u32 seclen)
+void security_release_secctx(struct lsmcontext *cp)
 {
 	struct security_hook_list *hp;
-	int ilsm = lsm_task_ilsm(current);
 
 	hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list)
-		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot) {
-			hp->hook.release_secctx(secdata, seclen);
-			return;
+		if (cp->slot == hp->lsmid->slot) {
+			hp->hook.release_secctx(cp->context, cp->len);
+			break;
 		}
+
+	memset(cp, 0, sizeof(*cp));
 }
 EXPORT_SYMBOL(security_release_secctx);
 
-- 
2.29.2

Re: [PATCH v26 15/25] LSM: Ensure the correct LSM context releaser

[Paul Moore]

On Thu, May 13, 2021 at 4:24 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
>
> Add a new lsmcontext data structure to hold all the information
> about a "security context", including the string, its size and
> which LSM allocated the string. The allocation information is
> necessary because LSMs have different policies regarding the
> lifecycle of these strings. SELinux allocates and destroys
> them on each use, whereas Smack provides a pointer to an entry
> in a list that never goes away.
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: John Johansen <john.johansen@canonical.com>
> Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
> Acked-by: Chuck Lever <chuck.lever@oracle.com>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> Cc: linux-integrity@vger.kernel.org
> Cc: netdev@vger.kernel.org
> Cc: linux-audit@redhat.com
> Cc: netfilter-devel@vger.kernel.org
> To: Pablo Neira Ayuso <pablo@netfilter.org>
> Cc: linux-nfs@vger.kernel.org
> ---
>  drivers/android/binder.c                | 10 ++++---
>  fs/ceph/xattr.c                         |  6 ++++-
>  fs/nfs/nfs4proc.c                       |  8 ++++--
>  fs/nfsd/nfs4xdr.c                       |  7 +++--
>  include/linux/security.h                | 35 +++++++++++++++++++++++--
>  include/net/scm.h                       |  5 +++-
>  kernel/audit.c                          | 14 +++++++---
>  kernel/auditsc.c                        | 12 ++++++---
>  net/ipv4/ip_sockglue.c                  |  4 ++-
>  net/netfilter/nf_conntrack_netlink.c    |  4 ++-
>  net/netfilter/nf_conntrack_standalone.c |  4 ++-
>  net/netfilter/nfnetlink_queue.c         | 13 ++++++---
>  net/netlabel/netlabel_unlabeled.c       | 19 +++++++++++---
>  net/netlabel/netlabel_user.c            |  4 ++-
>  security/security.c                     | 11 ++++----
>  15 files changed, 121 insertions(+), 35 deletions(-)

Acked-by: Paul Moore <paul@paul-moore.com>


--
paul moore
www.paul-moore.com

[PATCH v26 16/25] LSM: Use lsmcontext in security_secid_to_secctx

[Casey Schaufler]

Replace the (secctx,seclen) pointer pair with a single
lsmcontext pointer to allow return of the LSM identifier
along with the context and context length. This allows
security_release_secctx() to know how to release the
context. Callers have been modified to use or save the
returned data from the new structure.

Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: netdev@vger.kernel.org
Cc: linux-audit@redhat.com
Cc: netfilter-devel@vger.kernel.org
---
 drivers/android/binder.c                | 26 +++++++---------
 include/linux/security.h                |  4 +--
 include/net/scm.h                       |  9 ++----
 kernel/audit.c                          | 39 +++++++++++-------------
 kernel/auditsc.c                        | 31 +++++++------------
 net/ipv4/ip_sockglue.c                  |  8 ++---
 net/netfilter/nf_conntrack_netlink.c    | 18 +++++------
 net/netfilter/nf_conntrack_standalone.c |  7 ++---
 net/netfilter/nfnetlink_queue.c         |  5 +++-
 net/netlabel/netlabel_unlabeled.c       | 40 ++++++++-----------------
 net/netlabel/netlabel_user.c            |  7 ++---
 security/security.c                     | 10 +++++--
 12 files changed, 81 insertions(+), 123 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index eca789340ef6..f2a27bbbbe4d 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2459,9 +2459,7 @@ static void binder_transaction(struct binder_proc *proc,
 	binder_size_t last_fixup_min_off = 0;
 	struct binder_context *context = proc->context;
 	int t_debug_id = atomic_inc_return(&binder_last_id);
-	char *secctx = NULL;
-	u32 secctx_sz = 0;
-	struct lsmcontext scaff; /* scaffolding */
+	struct lsmcontext lsmctx = { };
 
 	e = binder_transaction_log_add(&binder_transaction_log);
 	e->debug_id = t_debug_id;
@@ -2724,14 +2722,14 @@ static void binder_transaction(struct binder_proc *proc,
 		 * case well anyway.
 		 */
 		security_task_getsecid_obj(proc->tsk, &blob);
-		ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz);
+		ret = security_secid_to_secctx(&blob, &lsmctx);
 		if (ret) {
 			return_error = BR_FAILED_REPLY;
 			return_error_param = ret;
 			return_error_line = __LINE__;
 			goto err_get_secctx_failed;
 		}
-		added_size = ALIGN(secctx_sz, sizeof(u64));
+		added_size = ALIGN(lsmctx.len, sizeof(u64));
 		extra_buffers_size += added_size;
 		if (extra_buffers_size < added_size) {
 			/* integer overflow of extra_buffers_size */
@@ -2758,24 +2756,22 @@ static void binder_transaction(struct binder_proc *proc,
 		t->buffer = NULL;
 		goto err_binder_alloc_buf_failed;
 	}
-	if (secctx) {
+	if (lsmctx.context) {
 		int err;
 		size_t buf_offset = ALIGN(tr->data_size, sizeof(void *)) +
 				    ALIGN(tr->offsets_size, sizeof(void *)) +
 				    ALIGN(extra_buffers_size, sizeof(void *)) -
-				    ALIGN(secctx_sz, sizeof(u64));
+				    ALIGN(lsmctx.len, sizeof(u64));
 
 		t->security_ctx = (uintptr_t)t->buffer->user_data + buf_offset;
 		err = binder_alloc_copy_to_buffer(&target_proc->alloc,
 						  t->buffer, buf_offset,
-						  secctx, secctx_sz);
+						  lsmctx.context, lsmctx.len);
 		if (err) {
 			t->security_ctx = 0;
 			WARN_ON(1);
 		}
-		lsmcontext_init(&scaff, secctx, secctx_sz, 0);
-		security_release_secctx(&scaff);
-		secctx = NULL;
+		security_release_secctx(&lsmctx);
 	}
 	t->buffer->debug_id = t->debug_id;
 	t->buffer->transaction = t;
@@ -2832,7 +2828,7 @@ static void binder_transaction(struct binder_proc *proc,
 	off_end_offset = off_start_offset + tr->offsets_size;
 	sg_buf_offset = ALIGN(off_end_offset, sizeof(void *));
 	sg_buf_end_offset = sg_buf_offset + extra_buffers_size -
-		ALIGN(secctx_sz, sizeof(u64));
+		ALIGN(lsmctx.len, sizeof(u64));
 	off_min = 0;
 	for (buffer_offset = off_start_offset; buffer_offset < off_end_offset;
 	     buffer_offset += sizeof(binder_size_t)) {
@@ -3116,10 +3112,8 @@ static void binder_transaction(struct binder_proc *proc,
 	binder_alloc_free_buf(&target_proc->alloc, t->buffer);
 err_binder_alloc_buf_failed:
 err_bad_extra_size:
-	if (secctx) {
-		lsmcontext_init(&scaff, secctx, secctx_sz, 0);
-		security_release_secctx(&scaff);
-	}
+	if (lsmctx.context)
+		security_release_secctx(&lsmctx);
 err_get_secctx_failed:
 	kfree(tcomplete);
 	binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
diff --git a/include/linux/security.h b/include/linux/security.h
index 3b2ffef65b05..666bd85e142b 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -578,7 +578,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 			 size_t size);
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
-int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen);
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp);
 int security_secctx_to_secid(const char *secdata, u32 seclen,
 			     struct lsmblob *blob);
 void security_release_secctx(struct lsmcontext *cp);
@@ -1433,7 +1433,7 @@ static inline int security_ismaclabel(const char *name)
 }
 
 static inline int security_secid_to_secctx(struct lsmblob *blob,
-					   char **secdata, u32 *seclen)
+					   struct lsmcontext *cp)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/include/net/scm.h b/include/net/scm.h
index f273c4d777ec..b77a52f93389 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -94,8 +94,6 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
 {
 	struct lsmcontext context;
 	struct lsmblob lb;
-	char *secdata;
-	u32 seclen;
 	int err;
 
 	if (test_bit(SOCK_PASSSEC, &sock->flags)) {
@@ -103,12 +101,11 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
 		 * and the infrastructure will know which it is.
 		 */
 		lsmblob_init(&lb, scm->secid);
-		err = security_secid_to_secctx(&lb, &secdata, &seclen);
+		err = security_secid_to_secctx(&lb, &context);
 
 		if (!err) {
-			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
-			/*scaffolding*/
-			lsmcontext_init(&context, secdata, seclen, 0);
+			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, context.len,
+				 context.context);
 			security_release_secctx(&context);
 		}
 	}
diff --git a/kernel/audit.c b/kernel/audit.c
index c17ec23158c4..841123390d41 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1190,9 +1190,6 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	struct audit_buffer	*ab;
 	u16			msg_type = nlh->nlmsg_type;
 	struct audit_sig_info   *sig_data;
-	char			*ctx = NULL;
-	u32			len;
-	struct lsmcontext	scaff; /* scaffolding */
 
 	err = audit_netlink_ok(skb, msg_type);
 	if (err)
@@ -1440,33 +1437,34 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		kfree(new);
 		break;
 	}
-	case AUDIT_SIGNAL_INFO:
-		len = 0;
+	case AUDIT_SIGNAL_INFO: {
+		struct lsmcontext context = { };
+		int len = 0;
+
 		if (lsmblob_is_set(&audit_sig_lsm)) {
-			err = security_secid_to_secctx(&audit_sig_lsm, &ctx,
-						       &len);
+			err = security_secid_to_secctx(&audit_sig_lsm,
+						       &context);
 			if (err)
 				return err;
 		}
-		sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
+		sig_data = kmalloc(sizeof(*sig_data) + context.len, GFP_KERNEL);
 		if (!sig_data) {
-			if (lsmblob_is_set(&audit_sig_lsm)) {
-				lsmcontext_init(&scaff, ctx, len, 0);
-				security_release_secctx(&scaff);
-			}
+			if (lsmblob_is_set(&audit_sig_lsm))
+				security_release_secctx(&context);
 			return -ENOMEM;
 		}
 		sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
 		sig_data->pid = audit_sig_pid;
 		if (lsmblob_is_set(&audit_sig_lsm)) {
-			memcpy(sig_data->ctx, ctx, len);
-			lsmcontext_init(&scaff, ctx, len, 0);
-			security_release_secctx(&scaff);
+			len = context.len;
+			memcpy(sig_data->ctx, context.context, len);
+			security_release_secctx(&context);
 		}
 		audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
 				 sig_data, sizeof(*sig_data) + len);
 		kfree(sig_data);
 		break;
+	}
 	case AUDIT_TTY_GET: {
 		struct audit_tty_status s;
 		unsigned int t;
@@ -2132,26 +2130,23 @@ void audit_log_key(struct audit_buffer *ab, char *key)
 
 int audit_log_task_context(struct audit_buffer *ab)
 {
-	char *ctx = NULL;
-	unsigned len;
 	int error;
 	struct lsmblob blob;
-	struct lsmcontext scaff; /* scaffolding */
+	struct lsmcontext context;
 
 	security_task_getsecid_subj(current, &blob);
 	if (!lsmblob_is_set(&blob))
 		return 0;
 
-	error = security_secid_to_secctx(&blob, &ctx, &len);
+	error = security_secid_to_secctx(&blob, &context);
 	if (error) {
 		if (error != -EINVAL)
 			goto error_path;
 		return 0;
 	}
 
-	audit_log_format(ab, " subj=%s", ctx);
-	lsmcontext_init(&scaff, ctx, len, 0);
-	security_release_secctx(&scaff);
+	audit_log_format(ab, " subj=%s", context.context);
+	security_release_secctx(&context);
 	return 0;
 
 error_path:
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 3fb9d3639123..67da23f6bebd 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -996,9 +996,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 				 struct lsmblob *blob, char *comm)
 {
 	struct audit_buffer *ab;
-	struct lsmcontext lsmcxt;
-	char *ctx = NULL;
-	u32 len;
+	struct lsmcontext lsmctx;
 	int rc = 0;
 
 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
@@ -1009,13 +1007,12 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
 	if (lsmblob_is_set(blob)) {
-		if (security_secid_to_secctx(blob, &ctx, &len)) {
+		if (security_secid_to_secctx(blob, &lsmctx)) {
 			audit_log_format(ab, " obj=(none)");
 			rc = 1;
 		} else {
-			audit_log_format(ab, " obj=%s", ctx);
-			lsmcontext_init(&lsmcxt, ctx, len, 0); /*scaffolding*/
-			security_release_secctx(&lsmcxt);
+			audit_log_format(ab, " obj=%s", lsmctx.context);
+			security_release_secctx(&lsmctx);
 		}
 	}
 	audit_log_format(ab, " ocomm=");
@@ -1228,7 +1225,6 @@ static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
 
 static void show_special(struct audit_context *context, int *call_panic)
 {
-	struct lsmcontext lsmcxt;
 	struct audit_buffer *ab;
 	int i;
 
@@ -1252,17 +1248,15 @@ static void show_special(struct audit_context *context, int *call_panic)
 				 from_kgid(&init_user_ns, context->ipc.gid),
 				 context->ipc.mode);
 		if (osid) {
-			char *ctx = NULL;
-			u32 len;
+			struct lsmcontext lsmcxt;
 			struct lsmblob blob;
 
 			lsmblob_init(&blob, osid);
-			if (security_secid_to_secctx(&blob, &ctx, &len)) {
+			if (security_secid_to_secctx(&blob, &lsmcxt)) {
 				audit_log_format(ab, " osid=%u", osid);
 				*call_panic = 1;
 			} else {
-				audit_log_format(ab, " obj=%s", ctx);
-				lsmcontext_init(&lsmcxt, ctx, len, 0);
+				audit_log_format(ab, " obj=%s", lsmcxt.context);
 				security_release_secctx(&lsmcxt);
 			}
 		}
@@ -1409,20 +1403,17 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 				 MAJOR(n->rdev),
 				 MINOR(n->rdev));
 	if (n->osid != 0) {
-		char *ctx = NULL;
-		u32 len;
 		struct lsmblob blob;
-		struct lsmcontext lsmcxt;
+		struct lsmcontext lsmctx;
 
 		lsmblob_init(&blob, n->osid);
-		if (security_secid_to_secctx(&blob, &ctx, &len)) {
+		if (security_secid_to_secctx(&blob, &lsmctx)) {
 			audit_log_format(ab, " osid=%u", n->osid);
 			if (call_panic)
 				*call_panic = 2;
 		} else {
-			audit_log_format(ab, " obj=%s", ctx);
-			lsmcontext_init(&lsmcxt, ctx, len, 0); /* scaffolding */
-			security_release_secctx(&lsmcxt);
+			audit_log_format(ab, " obj=%s", lsmctx.context);
+			security_release_secctx(&lsmctx);
 		}
 	}
 
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index a7e4c1b34b6c..ae073b642fa7 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -132,8 +132,7 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 {
 	struct lsmcontext context;
 	struct lsmblob lb;
-	char *secdata;
-	u32 seclen, secid;
+	u32 secid;
 	int err;
 
 	err = security_socket_getpeersec_dgram(NULL, skb, &secid);
@@ -141,12 +140,11 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 		return;
 
 	lsmblob_init(&lb, secid);
-	err = security_secid_to_secctx(&lb, &secdata, &seclen);
+	err = security_secid_to_secctx(&lb, &context);
 	if (err)
 		return;
 
-	put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata);
-	lsmcontext_init(&context, secdata, seclen, 0); /* scaffolding */
+	put_cmsg(msg, SOL_IP, SCM_SECURITY, context.len, context.context);
 	security_release_secctx(&context);
 }
 
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 914ab6a96573..215d3f9e9715 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -336,8 +336,7 @@ static int ctnetlink_dump_mark(struct sk_buff *skb, const struct nf_conn *ct)
 static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 {
 	struct nlattr *nest_secctx;
-	int len, ret;
-	char *secctx;
+	int ret;
 	struct lsmblob blob;
 	struct lsmcontext context;
 
@@ -345,7 +344,7 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	 * security_secid_to_secctx() will know which security module
 	 * to use to create the secctx.  */
 	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, &secctx, &len);
+	ret = security_secid_to_secctx(&blob, &context);
 	if (ret)
 		return 0;
 
@@ -354,13 +353,12 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	if (!nest_secctx)
 		goto nla_put_failure;
 
-	if (nla_put_string(skb, CTA_SECCTX_NAME, secctx))
+	if (nla_put_string(skb, CTA_SECCTX_NAME, context.context))
 		goto nla_put_failure;
 	nla_nest_end(skb, nest_secctx);
 
 	ret = 0;
 nla_put_failure:
-	lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
 	security_release_secctx(&context);
 	return ret;
 }
@@ -655,15 +653,15 @@ static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 	int len, ret;
 	struct lsmblob blob;
+	struct lsmcontext context;
 
-	/* lsmblob_init() puts ct->secmark into all of the secids in blob.
-	 * security_secid_to_secctx() will know which security module
-	 * to use to create the secctx.  */
-	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, NULL, &len);
+	ret = security_secid_to_secctx(&blob, &context);
 	if (ret)
 		return 0;
 
+	len = context.len;
+	security_release_secctx(&context);
+
 	return nla_total_size(0) /* CTA_SECCTX */
 	       + nla_total_size(sizeof(char) * len); /* CTA_SECCTX_NAME */
 #else
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index b039445f3efc..df6043d1bc22 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -173,19 +173,16 @@ static void ct_seq_stop(struct seq_file *s, void *v)
 static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 {
 	int ret;
-	u32 len;
-	char *secctx;
 	struct lsmblob blob;
 	struct lsmcontext context;
 
 	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, &secctx, &len);
+	ret = security_secid_to_secctx(&blob, &context);
 	if (ret)
 		return;
 
-	seq_printf(s, "secctx=%s ", secctx);
+	seq_printf(s, "secctx=%s ", context.context);
 
-	lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
 	security_release_secctx(&context);
 }
 #else
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 06b7751c7668..719ec0f0f2ab 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -306,6 +306,7 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
 	u32 seclen = 0;
 #if IS_ENABLED(CONFIG_NETWORK_SECMARK)
 	struct lsmblob blob;
+	struct lsmcontext context = { };
 
 	if (!skb || !sk_fullsock(skb->sk))
 		return 0;
@@ -317,10 +318,12 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
 		 * blob. security_secid_to_secctx() will know which security
 		 * module to use to create the secctx.  */
 		lsmblob_init(&blob, skb->secmark);
-		security_secid_to_secctx(&blob, secdata, &seclen);
+		security_secid_to_secctx(&blob, &context);
+		*secdata = context.context;
 	}
 
 	read_unlock_bh(&skb->sk->sk_callback_lock);
+	seclen = context.len;
 #endif
 	return seclen;
 }
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 8ca1e2b33dcf..3daa99396335 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -375,8 +375,6 @@ int netlbl_unlhsh_add(struct net *net,
 	struct netlbl_unlhsh_iface *iface;
 	struct audit_buffer *audit_buf = NULL;
 	struct lsmcontext context;
-	char *secctx = NULL;
-	u32 secctx_len;
 	struct lsmblob blob;
 
 	if (addr_len != sizeof(struct in_addr) &&
@@ -444,12 +442,9 @@ int netlbl_unlhsh_add(struct net *net,
 		 * security_secid_to_secctx() will know which security module
 		 * to use to create the secctx.  */
 		lsmblob_init(&blob, secid);
-		if (security_secid_to_secctx(&blob,
-					     &secctx,
-					     &secctx_len) == 0) {
-			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			/* scaffolding */
-			lsmcontext_init(&context, secctx, secctx_len, 0);
+		if (security_secid_to_secctx(&blob, &context) == 0) {
+			audit_log_format(audit_buf, " sec_obj=%s",
+					 context.context);
 			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0);
@@ -482,8 +477,6 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
 	struct lsmcontext context;
-	char *secctx;
-	u32 secctx_len;
 	struct lsmblob blob;
 
 	spin_lock(&netlbl_unlhsh_lock);
@@ -510,11 +503,9 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 		if (entry != NULL)
 			lsmblob_init(&blob, entry->secid);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&blob,
-					     &secctx, &secctx_len) == 0) {
-			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			/* scaffolding */
-			lsmcontext_init(&context, secctx, secctx_len, 0);
+		    security_secid_to_secctx(&blob, &context) == 0) {
+			audit_log_format(audit_buf, " sec_obj=%s",
+					 context.context);
 			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
@@ -553,8 +544,6 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
 	struct lsmcontext context;
-	char *secctx;
-	u32 secctx_len;
 	struct lsmblob blob;
 
 	spin_lock(&netlbl_unlhsh_lock);
@@ -580,10 +569,9 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 		if (entry != NULL)
 			lsmblob_init(&blob, entry->secid);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&blob,
-					     &secctx, &secctx_len) == 0) {
-			audit_log_format(audit_buf, " sec_obj=%s", secctx);
-			lsmcontext_init(&context, secctx, secctx_len, 0);
+		    security_secid_to_secctx(&blob, &context) == 0) {
+			audit_log_format(audit_buf, " sec_obj=%s",
+					 context.context);
 			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
@@ -1106,8 +1094,6 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 	struct lsmcontext context;
 	void *data;
 	u32 secid;
-	char *secctx;
-	u32 secctx_len;
 	struct lsmblob blob;
 
 	data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).portid,
@@ -1167,15 +1153,13 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 	 * security_secid_to_secctx() will know which security module
 	 * to use to create the secctx.  */
 	lsmblob_init(&blob, secid);
-	ret_val = security_secid_to_secctx(&blob, &secctx, &secctx_len);
+	ret_val = security_secid_to_secctx(&blob, &context);
 	if (ret_val != 0)
 		goto list_cb_failure;
 	ret_val = nla_put(cb_arg->skb,
 			  NLBL_UNLABEL_A_SECCTX,
-			  secctx_len,
-			  secctx);
-	/* scaffolding */
-	lsmcontext_init(&context, secctx, secctx_len, 0);
+			  context.len,
+			  context.context);
 	security_release_secctx(&context);
 	if (ret_val != 0)
 		goto list_cb_failure;
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index ef139d8ae7cd..951ba0639d20 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -85,8 +85,6 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 {
 	struct audit_buffer *audit_buf;
 	struct lsmcontext context;
-	char *secctx;
-	u32 secctx_len;
 	struct lsmblob blob;
 
 	if (audit_enabled == AUDIT_OFF)
@@ -102,9 +100,8 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 
 	lsmblob_init(&blob, audit_info->secid);
 	if (audit_info->secid != 0 &&
-	    security_secid_to_secctx(&blob, &secctx, &secctx_len) == 0) {
-		audit_log_format(audit_buf, " subj=%s", secctx);
-		lsmcontext_init(&context, secctx, secctx_len, 0);/*scaffolding*/
+	    security_secid_to_secctx(&blob, &context) == 0) {
+		audit_log_format(audit_buf, " subj=%s", context.context);
 		security_release_secctx(&context);
 	}
 
diff --git a/security/security.c b/security/security.c
index f6a33bf2a7fc..5bb41ca1fa9f 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2323,18 +2323,22 @@ int security_ismaclabel(const char *name)
 }
 EXPORT_SYMBOL(security_ismaclabel);
 
-int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen)
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp)
 {
 	struct security_hook_list *hp;
 	int ilsm = lsm_task_ilsm(current);
 
+	memset(cp, 0, sizeof(*cp));
+
 	hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
-		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot)
+		if (ilsm == LSMBLOB_INVALID || ilsm == hp->lsmid->slot) {
+			cp->slot = hp->lsmid->slot;
 			return hp->hook.secid_to_secctx(
 					blob->secid[hp->lsmid->slot],
-					secdata, seclen);
+					&cp->context, &cp->len);
+		}
 	}
 
 	return LSM_RET_DEFAULT(secid_to_secctx);
-- 
2.29.2

[PATCH v26 17/25] LSM: Use lsmcontext in security_inode_getsecctx

[Casey Schaufler]

Change the security_inode_getsecctx() interface to fill
a lsmcontext structure instead of data and length pointers.
This provides the information about which LSM created the
context so that security_release_secctx() can use the
correct hook.

Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-nfs@vger.kernel.org
---
 fs/nfsd/nfs4xdr.c        | 23 +++++++++--------------
 include/linux/security.h |  5 +++--
 security/security.c      | 13 +++++++++++--
 3 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 089ec4b61ef1..fc7ba114c298 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2727,11 +2727,11 @@ nfsd4_encode_layout_types(struct xdr_stream *xdr, u32 layout_types)
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 static inline __be32
 nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
-			    void *context, int len)
+			    struct lsmcontext *context)
 {
 	__be32 *p;
 
-	p = xdr_reserve_space(xdr, len + 4 + 4 + 4);
+	p = xdr_reserve_space(xdr, context->len + 4 + 4 + 4);
 	if (!p)
 		return nfserr_resource;
 
@@ -2741,13 +2741,13 @@ nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
 	 */
 	*p++ = cpu_to_be32(0); /* lfs */
 	*p++ = cpu_to_be32(0); /* pi */
-	p = xdr_encode_opaque(p, context, len);
+	p = xdr_encode_opaque(p, context->context, context->len);
 	return 0;
 }
 #else
 static inline __be32
 nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
-			    void *context, int len)
+			    struct lsmcontext *context)
 { return 0; }
 #endif
 
@@ -2844,9 +2844,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	int err;
 	struct nfs4_acl *acl = NULL;
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
-	struct lsmcontext scaff; /* scaffolding */
-	void *context = NULL;
-	int contextlen;
+	struct lsmcontext context = { };
 #endif
 	bool contextsupport = false;
 	struct nfsd4_compoundres *resp = rqstp->rq_resp;
@@ -2904,7 +2902,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	     bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
 		if (exp->ex_flags & NFSEXP_SECURITY_LABEL)
 			err = security_inode_getsecctx(d_inode(dentry),
-						&context, &contextlen);
+						       &context);
 		else
 			err = -EOPNOTSUPP;
 		contextsupport = (err == 0);
@@ -3324,8 +3322,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
 	if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) {
-		status = nfsd4_encode_security_label(xdr, rqstp, context,
-								contextlen);
+		status = nfsd4_encode_security_label(xdr, rqstp, &context);
 		if (status)
 			goto out;
 	}
@@ -3346,10 +3343,8 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 
 out:
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
-	if (context) {
-		lsmcontext_init(&scaff, context, contextlen, 0); /*scaffolding*/
-		security_release_secctx(&scaff);
-	}
+	if (context.context)
+		security_release_secctx(&context);
 #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
 	kfree(acl);
 	if (tempfh) {
diff --git a/include/linux/security.h b/include/linux/security.h
index 666bd85e142b..0129400ff6e9 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -585,7 +585,7 @@ void security_release_secctx(struct lsmcontext *cp);
 void security_inode_invalidate_secctx(struct inode *inode);
 int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
 int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);
-int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
+int security_inode_getsecctx(struct inode *inode, struct lsmcontext *cp);
 int security_locked_down(enum lockdown_reason what);
 #else /* CONFIG_SECURITY */
 
@@ -1461,7 +1461,8 @@ static inline int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32
 {
 	return -EOPNOTSUPP;
 }
-static inline int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+static inline int security_inode_getsecctx(struct inode *inode,
+					   struct lsmcontext *cp)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/security/security.c b/security/security.c
index 5bb41ca1fa9f..1e441c3491b5 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2395,9 +2395,18 @@ int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
 }
 EXPORT_SYMBOL(security_inode_setsecctx);
 
-int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+int security_inode_getsecctx(struct inode *inode, struct lsmcontext *cp)
 {
-	return call_int_hook(inode_getsecctx, -EOPNOTSUPP, inode, ctx, ctxlen);
+	struct security_hook_list *hp;
+
+	memset(cp, 0, sizeof(*cp));
+
+	hlist_for_each_entry(hp, &security_hook_heads.inode_getsecctx, list) {
+		cp->slot = hp->lsmid->slot;
+		return hp->hook.inode_getsecctx(inode, (void **)&cp->context,
+						&cp->len);
+	}
+	return -EOPNOTSUPP;
 }
 EXPORT_SYMBOL(security_inode_getsecctx);
 
-- 
2.29.2

Re: [PATCH v26 17/25] LSM: Use lsmcontext in security_inode_getsecctx

[Kees Cook]

On Thu, May 13, 2021 at 01:07:59PM -0700, Casey Schaufler wrote:
> Change the security_inode_getsecctx() interface to fill
> a lsmcontext structure instead of data and length pointers.
> This provides the information about which LSM created the
> context so that security_release_secctx() can use the
> correct hook.
> 
> Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
> Acked-by: Paul Moore <paul@paul-moore.com>
> Acked-by: Chuck Lever <chuck.lever@oracle.com>
> Reviewed-by: John Johansen <john.johansen@canonical.com>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

Seem good to me.

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

[PATCH v26 18/25] LSM: security_secid_to_secctx in netlink netfilter

[Casey Schaufler]

Change netlink netfilter interfaces to use lsmcontext
pointers, and remove scaffolding.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: netdev@vger.kernel.org
Cc: netfilter-devel@vger.kernel.org
---
 net/netfilter/nfnetlink_queue.c | 37 +++++++++++++--------------------
 1 file changed, 14 insertions(+), 23 deletions(-)

diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 719ec0f0f2ab..bf8db099090b 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -301,15 +301,13 @@ static int nfqnl_put_sk_uidgid(struct sk_buff *skb, struct sock *sk)
 	return -1;
 }
 
-static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
+static void nfqnl_get_sk_secctx(struct sk_buff *skb, struct lsmcontext *context)
 {
-	u32 seclen = 0;
 #if IS_ENABLED(CONFIG_NETWORK_SECMARK)
 	struct lsmblob blob;
-	struct lsmcontext context = { };
 
 	if (!skb || !sk_fullsock(skb->sk))
-		return 0;
+		return;
 
 	read_lock_bh(&skb->sk->sk_callback_lock);
 
@@ -318,14 +316,12 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
 		 * blob. security_secid_to_secctx() will know which security
 		 * module to use to create the secctx.  */
 		lsmblob_init(&blob, skb->secmark);
-		security_secid_to_secctx(&blob, &context);
-		*secdata = context.context;
+		security_secid_to_secctx(&blob, context);
 	}
 
 	read_unlock_bh(&skb->sk->sk_callback_lock);
-	seclen = context.len;
 #endif
-	return seclen;
+	return;
 }
 
 static u32 nfqnl_get_bridge_size(struct nf_queue_entry *entry)
@@ -397,12 +393,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	struct net_device *indev;
 	struct net_device *outdev;
 	struct nf_conn *ct = NULL;
+	struct lsmcontext context = { };
 	enum ip_conntrack_info ctinfo;
 	struct nfnl_ct_hook *nfnl_ct;
 	bool csum_verify;
-	struct lsmcontext scaff; /* scaffolding */
-	char *secdata = NULL;
-	u32 seclen = 0;
 
 	size = nlmsg_total_size(sizeof(struct nfgenmsg))
 		+ nla_total_size(sizeof(struct nfqnl_msg_packet_hdr))
@@ -470,9 +464,9 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	}
 
 	if ((queue->flags & NFQA_CFG_F_SECCTX) && entskb->sk) {
-		seclen = nfqnl_get_sk_secctx(entskb, &secdata);
-		if (seclen)
-			size += nla_total_size(seclen);
+		nfqnl_get_sk_secctx(entskb, &context);
+		if (context.len)
+			size += nla_total_size(context.len);
 	}
 
 	skb = alloc_skb(size, GFP_ATOMIC);
@@ -602,7 +596,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	    nfqnl_put_sk_uidgid(skb, entskb->sk) < 0)
 		goto nla_put_failure;
 
-	if (seclen && nla_put(skb, NFQA_SECCTX, seclen, secdata))
+	if (context.len &&
+	    nla_put(skb, NFQA_SECCTX, context.len, context.context))
 		goto nla_put_failure;
 
 	if (ct && nfnl_ct->build(skb, ct, ctinfo, NFQA_CT, NFQA_CT_INFO) < 0)
@@ -630,10 +625,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	}
 
 	nlh->nlmsg_len = skb->len;
-	if (seclen) {
-		lsmcontext_init(&scaff, secdata, seclen, 0);
-		security_release_secctx(&scaff);
-	}
+	if (context.len)
+		security_release_secctx(&context);
 	return skb;
 
 nla_put_failure:
@@ -641,10 +634,8 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
 	kfree_skb(skb);
 	net_err_ratelimited("nf_queue: error creating packet message\n");
 nlmsg_failure:
-	if (seclen) {
-		lsmcontext_init(&scaff, secdata, seclen, 0);
-		security_release_secctx(&scaff);
-	}
+	if (context.len)
+		security_release_secctx(&context);
 	return NULL;
 }
 
-- 
2.29.2

Re: [PATCH v26 18/25] LSM: security_secid_to_secctx in netlink netfilter

[Paul Moore]

On Thu, May 13, 2021 at 4:28 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
>
> Change netlink netfilter interfaces to use lsmcontext
> pointers, and remove scaffolding.
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: John Johansen <john.johansen@canonical.com>
> Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
> Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> Cc: netdev@vger.kernel.org
> Cc: netfilter-devel@vger.kernel.org
> ---
>  net/netfilter/nfnetlink_queue.c | 37 +++++++++++++--------------------
>  1 file changed, 14 insertions(+), 23 deletions(-)

Acked-by: Paul Moore <paul@paul-moore.com>


--
paul moore
www.paul-moore.com

[PATCH v26 19/25] NET: Store LSM netlabel data in a lsmblob

[Casey Schaufler]

Netlabel uses LSM interfaces requiring an lsmblob and
the internal storage is used to pass information between
these interfaces, so change the internal data from a secid
to a lsmblob. Update the netlabel interfaces and their
callers to accommodate the change. This requires that the
modules using netlabel use the lsm_id.slot to access the
correct secid when using netlabel.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: netdev@vger.kernel.org
---
 include/net/netlabel.h              |  8 +--
 net/ipv4/cipso_ipv4.c               | 26 ++++++----
 net/netlabel/netlabel_kapi.c        |  6 +--
 net/netlabel/netlabel_unlabeled.c   | 79 +++++++++--------------------
 net/netlabel/netlabel_unlabeled.h   |  2 +-
 security/selinux/hooks.c            |  2 +-
 security/selinux/include/security.h |  1 +
 security/selinux/netlabel.c         |  2 +-
 security/selinux/ss/services.c      |  4 +-
 security/smack/smack.h              |  1 +
 security/smack/smack_access.c       |  2 +-
 security/smack/smack_lsm.c          | 11 ++--
 security/smack/smackfs.c            | 10 ++--
 13 files changed, 68 insertions(+), 86 deletions(-)

diff --git a/include/net/netlabel.h b/include/net/netlabel.h
index 43ae50337685..73fc25b4042b 100644
--- a/include/net/netlabel.h
+++ b/include/net/netlabel.h
@@ -166,7 +166,7 @@ struct netlbl_lsm_catmap {
  * @attr.mls: MLS sensitivity label
  * @attr.mls.cat: MLS category bitmap
  * @attr.mls.lvl: MLS sensitivity level
- * @attr.secid: LSM specific secid token
+ * @attr.lsmblob: LSM specific data
  *
  * Description:
  * This structure is used to pass security attributes between NetLabel and the
@@ -201,7 +201,7 @@ struct netlbl_lsm_secattr {
 			struct netlbl_lsm_catmap *cat;
 			u32 lvl;
 		} mls;
-		u32 secid;
+		struct lsmblob lsmblob;
 	} attr;
 };
 
@@ -415,7 +415,7 @@ int netlbl_cfg_unlbl_static_add(struct net *net,
 				const void *addr,
 				const void *mask,
 				u16 family,
-				u32 secid,
+				struct lsmblob *lsmblob,
 				struct netlbl_audit *audit_info);
 int netlbl_cfg_unlbl_static_del(struct net *net,
 				const char *dev_name,
@@ -523,7 +523,7 @@ static inline int netlbl_cfg_unlbl_static_add(struct net *net,
 					      const void *addr,
 					      const void *mask,
 					      u16 family,
-					      u32 secid,
+					      struct lsmblob *lsmblob,
 					      struct netlbl_audit *audit_info)
 {
 	return -ENOSYS;
diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index bfaf327e9d12..6f289821edb7 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -106,15 +106,17 @@ int cipso_v4_rbm_strictvalid = 1;
 /* Base length of the local tag (non-standard tag).
  *  Tag definition (may change between kernel versions)
  *
- * 0          8          16         24         32
- * +----------+----------+----------+----------+
- * | 10000000 | 00000110 | 32-bit secid value  |
- * +----------+----------+----------+----------+
- * | in (host byte order)|
- * +----------+----------+
- *
+ * 0          8          16                    16 + sizeof(struct lsmblob)
+ * +----------+----------+---------------------+
+ * | 10000000 | 00000110 | LSM blob data       |
+ * +----------+----------+---------------------+
+ *
+ * All secid and flag fields are in host byte order.
+ * The lsmblob structure size varies depending on which
+ * Linux security modules are built in the kernel.
+ * The data is opaque.
  */
-#define CIPSO_V4_TAG_LOC_BLEN         6
+#define CIPSO_V4_TAG_LOC_BLEN         (2 + sizeof(struct lsmblob))
 
 /*
  * Helper Functions
@@ -1460,7 +1462,11 @@ static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def,
 
 	buffer[0] = CIPSO_V4_TAG_LOCAL;
 	buffer[1] = CIPSO_V4_TAG_LOC_BLEN;
-	*(u32 *)&buffer[2] = secattr->attr.secid;
+	/* Ensure that there is sufficient space in the CIPSO header
+	 * for the LSM data. */
+	BUILD_BUG_ON(CIPSO_V4_TAG_LOC_BLEN > CIPSO_V4_OPT_LEN_MAX);
+	memcpy(&buffer[2], &secattr->attr.lsmblob,
+	       sizeof(secattr->attr.lsmblob));
 
 	return CIPSO_V4_TAG_LOC_BLEN;
 }
@@ -1480,7 +1486,7 @@ static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def,
 				 const unsigned char *tag,
 				 struct netlbl_lsm_secattr *secattr)
 {
-	secattr->attr.secid = *(u32 *)&tag[2];
+	memcpy(&secattr->attr.lsmblob, &tag[2], sizeof(secattr->attr.lsmblob));
 	secattr->flags |= NETLBL_SECATTR_SECID;
 
 	return 0;
diff --git a/net/netlabel/netlabel_kapi.c b/net/netlabel/netlabel_kapi.c
index 5e1239cef000..bbfaff539416 100644
--- a/net/netlabel/netlabel_kapi.c
+++ b/net/netlabel/netlabel_kapi.c
@@ -196,7 +196,7 @@ int netlbl_cfg_unlbl_map_add(const char *domain,
  * @addr: IP address in network byte order (struct in[6]_addr)
  * @mask: address mask in network byte order (struct in[6]_addr)
  * @family: address family
- * @secid: LSM secid value for the entry
+ * @lsmblob: LSM data value for the entry
  * @audit_info: NetLabel audit information
  *
  * Description:
@@ -210,7 +210,7 @@ int netlbl_cfg_unlbl_static_add(struct net *net,
 				const void *addr,
 				const void *mask,
 				u16 family,
-				u32 secid,
+				struct lsmblob *lsmblob,
 				struct netlbl_audit *audit_info)
 {
 	u32 addr_len;
@@ -230,7 +230,7 @@ int netlbl_cfg_unlbl_static_add(struct net *net,
 
 	return netlbl_unlhsh_add(net,
 				 dev_name, addr, mask, addr_len,
-				 secid, audit_info);
+				 lsmblob, audit_info);
 }
 
 /**
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 3daa99396335..0ce9bee43dd3 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -66,7 +66,7 @@ struct netlbl_unlhsh_tbl {
 #define netlbl_unlhsh_addr4_entry(iter) \
 	container_of(iter, struct netlbl_unlhsh_addr4, list)
 struct netlbl_unlhsh_addr4 {
-	u32 secid;
+	struct lsmblob lsmblob;
 
 	struct netlbl_af4list list;
 	struct rcu_head rcu;
@@ -74,7 +74,7 @@ struct netlbl_unlhsh_addr4 {
 #define netlbl_unlhsh_addr6_entry(iter) \
 	container_of(iter, struct netlbl_unlhsh_addr6, list)
 struct netlbl_unlhsh_addr6 {
-	u32 secid;
+	struct lsmblob lsmblob;
 
 	struct netlbl_af6list list;
 	struct rcu_head rcu;
@@ -220,7 +220,7 @@ static struct netlbl_unlhsh_iface *netlbl_unlhsh_search_iface(int ifindex)
  * @iface: the associated interface entry
  * @addr: IPv4 address in network byte order
  * @mask: IPv4 address mask in network byte order
- * @secid: LSM secid value for entry
+ * @lsmblob: LSM data value for entry
  *
  * Description:
  * Add a new address entry into the unlabeled connection hash table using the
@@ -231,7 +231,7 @@ static struct netlbl_unlhsh_iface *netlbl_unlhsh_search_iface(int ifindex)
 static int netlbl_unlhsh_add_addr4(struct netlbl_unlhsh_iface *iface,
 				   const struct in_addr *addr,
 				   const struct in_addr *mask,
-				   u32 secid)
+				   struct lsmblob *lsmblob)
 {
 	int ret_val;
 	struct netlbl_unlhsh_addr4 *entry;
@@ -243,7 +243,7 @@ static int netlbl_unlhsh_add_addr4(struct netlbl_unlhsh_iface *iface,
 	entry->list.addr = addr->s_addr & mask->s_addr;
 	entry->list.mask = mask->s_addr;
 	entry->list.valid = 1;
-	entry->secid = secid;
+	entry->lsmblob = *lsmblob;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	ret_val = netlbl_af4list_add(&entry->list, &iface->addr4_list);
@@ -260,7 +260,7 @@ static int netlbl_unlhsh_add_addr4(struct netlbl_unlhsh_iface *iface,
  * @iface: the associated interface entry
  * @addr: IPv6 address in network byte order
  * @mask: IPv6 address mask in network byte order
- * @secid: LSM secid value for entry
+ * @lsmblob: LSM data value for entry
  *
  * Description:
  * Add a new address entry into the unlabeled connection hash table using the
@@ -271,7 +271,7 @@ static int netlbl_unlhsh_add_addr4(struct netlbl_unlhsh_iface *iface,
 static int netlbl_unlhsh_add_addr6(struct netlbl_unlhsh_iface *iface,
 				   const struct in6_addr *addr,
 				   const struct in6_addr *mask,
-				   u32 secid)
+				   struct lsmblob *lsmblob)
 {
 	int ret_val;
 	struct netlbl_unlhsh_addr6 *entry;
@@ -287,7 +287,7 @@ static int netlbl_unlhsh_add_addr6(struct netlbl_unlhsh_iface *iface,
 	entry->list.addr.s6_addr32[3] &= mask->s6_addr32[3];
 	entry->list.mask = *mask;
 	entry->list.valid = 1;
-	entry->secid = secid;
+	entry->lsmblob = *lsmblob;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	ret_val = netlbl_af6list_add(&entry->list, &iface->addr6_list);
@@ -366,7 +366,7 @@ int netlbl_unlhsh_add(struct net *net,
 		      const void *addr,
 		      const void *mask,
 		      u32 addr_len,
-		      u32 secid,
+		      struct lsmblob *lsmblob,
 		      struct netlbl_audit *audit_info)
 {
 	int ret_val;
@@ -375,7 +375,6 @@ int netlbl_unlhsh_add(struct net *net,
 	struct netlbl_unlhsh_iface *iface;
 	struct audit_buffer *audit_buf = NULL;
 	struct lsmcontext context;
-	struct lsmblob blob;
 
 	if (addr_len != sizeof(struct in_addr) &&
 	    addr_len != sizeof(struct in6_addr))
@@ -408,7 +407,7 @@ int netlbl_unlhsh_add(struct net *net,
 		const struct in_addr *addr4 = addr;
 		const struct in_addr *mask4 = mask;
 
-		ret_val = netlbl_unlhsh_add_addr4(iface, addr4, mask4, secid);
+		ret_val = netlbl_unlhsh_add_addr4(iface, addr4, mask4, lsmblob);
 		if (audit_buf != NULL)
 			netlbl_af4list_audit_addr(audit_buf, 1,
 						  dev_name,
@@ -421,7 +420,7 @@ int netlbl_unlhsh_add(struct net *net,
 		const struct in6_addr *addr6 = addr;
 		const struct in6_addr *mask6 = mask;
 
-		ret_val = netlbl_unlhsh_add_addr6(iface, addr6, mask6, secid);
+		ret_val = netlbl_unlhsh_add_addr6(iface, addr6, mask6, lsmblob);
 		if (audit_buf != NULL)
 			netlbl_af6list_audit_addr(audit_buf, 1,
 						  dev_name,
@@ -438,11 +437,7 @@ int netlbl_unlhsh_add(struct net *net,
 unlhsh_add_return:
 	rcu_read_unlock();
 	if (audit_buf != NULL) {
-		/* lsmblob_init() puts secid into all of the secids in blob.
-		 * security_secid_to_secctx() will know which security module
-		 * to use to create the secctx.  */
-		lsmblob_init(&blob, secid);
-		if (security_secid_to_secctx(&blob, &context) == 0) {
+		if (security_secid_to_secctx(lsmblob, &context) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -477,7 +472,6 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
 	struct lsmcontext context;
-	struct lsmblob blob;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	list_entry = netlbl_af4list_remove(addr->s_addr, mask->s_addr,
@@ -497,13 +491,8 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 					  addr->s_addr, mask->s_addr);
 		if (dev != NULL)
 			dev_put(dev);
-		/* lsmblob_init() puts entry->secid into all of the secids
-		 * in blob. security_secid_to_secctx() will know which
-		 * security module to use to create the secctx.  */
-		if (entry != NULL)
-			lsmblob_init(&blob, entry->secid);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&blob, &context) == 0) {
+		    security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -544,7 +533,6 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 	struct audit_buffer *audit_buf;
 	struct net_device *dev;
 	struct lsmcontext context;
-	struct lsmblob blob;
 
 	spin_lock(&netlbl_unlhsh_lock);
 	list_entry = netlbl_af6list_remove(addr, mask, &iface->addr6_list);
@@ -563,13 +551,8 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 					  addr, mask);
 		if (dev != NULL)
 			dev_put(dev);
-		/* lsmblob_init() puts entry->secid into all of the secids
-		 * in blob. security_secid_to_secctx() will know which
-		 * security module to use to create the secctx.  */
-		if (entry != NULL)
-			lsmblob_init(&blob, entry->secid);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&blob, &context) == 0) {
+		    security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
@@ -923,14 +906,8 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
 	if (ret_val != 0)
 		return ret_val;
 
-	/* netlbl_unlhsh_add will be changed to pass a struct lsmblob *
-	 * instead of a u32 later in this patch set. security_secctx_to_secid()
-	 * will only be setting one entry in the lsmblob struct, so it is
-	 * safe to use lsmblob_value() to get that one value. */
-
-	return netlbl_unlhsh_add(&init_net,
-				 dev_name, addr, mask, addr_len,
-				 lsmblob_value(&blob), &audit_info);
+	return netlbl_unlhsh_add(&init_net, dev_name, addr, mask, addr_len,
+				 &blob, &audit_info);
 }
 
 /**
@@ -977,11 +954,8 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
 	if (ret_val != 0)
 		return ret_val;
 
-	/* security_secctx_to_secid() will only put one secid into the lsmblob
-	 * so it's safe to use lsmblob_value() to get the secid. */
-	return netlbl_unlhsh_add(&init_net,
-				 NULL, addr, mask, addr_len,
-				 lsmblob_value(&blob), &audit_info);
+	return netlbl_unlhsh_add(&init_net, NULL, addr, mask, addr_len, &blob,
+				 &audit_info);
 }
 
 /**
@@ -1093,8 +1067,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 	struct net_device *dev;
 	struct lsmcontext context;
 	void *data;
-	u32 secid;
-	struct lsmblob blob;
+	struct lsmblob *lsmb;
 
 	data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).portid,
 			   cb_arg->seq, &netlbl_unlabel_gnl_family,
@@ -1132,7 +1105,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 		if (ret_val != 0)
 			goto list_cb_failure;
 
-		secid = addr4->secid;
+		lsmb = (struct lsmblob *)&addr4->lsmblob;
 	} else {
 		ret_val = nla_put_in6_addr(cb_arg->skb,
 					   NLBL_UNLABEL_A_IPV6ADDR,
@@ -1146,14 +1119,10 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 		if (ret_val != 0)
 			goto list_cb_failure;
 
-		secid = addr6->secid;
+		lsmb = (struct lsmblob *)&addr6->lsmblob;
 	}
 
-	/* lsmblob_init() secid into all of the secids in blob.
-	 * security_secid_to_secctx() will know which security module
-	 * to use to create the secctx.  */
-	lsmblob_init(&blob, secid);
-	ret_val = security_secid_to_secctx(&blob, &context);
+	ret_val = security_secid_to_secctx(lsmb, &context);
 	if (ret_val != 0)
 		goto list_cb_failure;
 	ret_val = nla_put(cb_arg->skb,
@@ -1512,7 +1481,7 @@ int netlbl_unlabel_getattr(const struct sk_buff *skb,
 					      &iface->addr4_list);
 		if (addr4 == NULL)
 			goto unlabel_getattr_nolabel;
-		secattr->attr.secid = netlbl_unlhsh_addr4_entry(addr4)->secid;
+		secattr->attr.lsmblob = netlbl_unlhsh_addr4_entry(addr4)->lsmblob;
 		break;
 	}
 #if IS_ENABLED(CONFIG_IPV6)
@@ -1525,7 +1494,7 @@ int netlbl_unlabel_getattr(const struct sk_buff *skb,
 					      &iface->addr6_list);
 		if (addr6 == NULL)
 			goto unlabel_getattr_nolabel;
-		secattr->attr.secid = netlbl_unlhsh_addr6_entry(addr6)->secid;
+		secattr->attr.lsmblob = netlbl_unlhsh_addr6_entry(addr6)->lsmblob;
 		break;
 	}
 #endif /* IPv6 */
diff --git a/net/netlabel/netlabel_unlabeled.h b/net/netlabel/netlabel_unlabeled.h
index 058e3a285d56..168920780994 100644
--- a/net/netlabel/netlabel_unlabeled.h
+++ b/net/netlabel/netlabel_unlabeled.h
@@ -211,7 +211,7 @@ int netlbl_unlhsh_add(struct net *net,
 		      const void *addr,
 		      const void *mask,
 		      u32 addr_len,
-		      u32 secid,
+		      struct lsmblob *lsmblob,
 		      struct netlbl_audit *audit_info);
 int netlbl_unlhsh_remove(struct net *net,
 			 const char *dev_name,
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index dba867721336..b7800fa55a34 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -7122,7 +7122,7 @@ static int selinux_perf_event_write(struct perf_event *event)
 }
 #endif
 
-static struct lsm_id selinux_lsmid __lsm_ro_after_init = {
+struct lsm_id selinux_lsmid __lsm_ro_after_init = {
 	.lsm  = "selinux",
 	.slot = LSMBLOB_NEEDED
 };
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index ac0ece01305a..9f856f2cd277 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -73,6 +73,7 @@
 struct netlbl_lsm_secattr;
 
 extern int selinux_enabled_boot;
+extern struct lsm_id selinux_lsmid;
 
 /*
  * type_datum properties
diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
index 6a94b31b5472..d8d7603ab14e 100644
--- a/security/selinux/netlabel.c
+++ b/security/selinux/netlabel.c
@@ -108,7 +108,7 @@ static struct netlbl_lsm_secattr *selinux_netlbl_sock_getattr(
 		return NULL;
 
 	if ((secattr->flags & NETLBL_SECATTR_SECID) &&
-	    (secattr->attr.secid == sid))
+	    (secattr->attr.lsmblob.secid[selinux_lsmid.slot] == sid))
 		return secattr;
 
 	return NULL;
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 0a5ce001609b..b6071e977cdf 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -3883,7 +3883,7 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state,
 	if (secattr->flags & NETLBL_SECATTR_CACHE)
 		*sid = *(u32 *)secattr->cache->data;
 	else if (secattr->flags & NETLBL_SECATTR_SECID)
-		*sid = secattr->attr.secid;
+		*sid = secattr->attr.lsmblob.secid[selinux_lsmid.slot];
 	else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
 		rc = -EIDRM;
 		ctx = sidtab_search(sidtab, SECINITSID_NETMSG);
@@ -3960,7 +3960,7 @@ int security_netlbl_sid_to_secattr(struct selinux_state *state,
 	if (secattr->domain == NULL)
 		goto out;
 
-	secattr->attr.secid = sid;
+	secattr->attr.lsmblob.secid[selinux_lsmid.slot] = sid;
 	secattr->flags |= NETLBL_SECATTR_DOMAIN_CPY | NETLBL_SECATTR_SECID;
 	mls_export_netlbl_lvl(policydb, ctx, secattr);
 	rc = mls_export_netlbl_cat(policydb, ctx, secattr);
diff --git a/security/smack/smack.h b/security/smack/smack.h
index b5bdf947792f..0eaae6b3f935 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -303,6 +303,7 @@ int smack_populate_secattr(struct smack_known *skp);
  * Shared data.
  */
 extern int smack_enabled;
+extern struct lsm_id smack_lsmid;
 extern int smack_cipso_direct;
 extern int smack_cipso_mapped;
 extern struct smack_known *smack_net_ambient;
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index 7eabb448acab..fccd5da3014e 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -522,7 +522,7 @@ int smack_populate_secattr(struct smack_known *skp)
 {
 	int slen;
 
-	skp->smk_netlabel.attr.secid = skp->smk_secid;
+	skp->smk_netlabel.attr.lsmblob.secid[smack_lsmid.slot] = skp->smk_secid;
 	skp->smk_netlabel.domain = skp->smk_known;
 	skp->smk_netlabel.cache = netlbl_secattr_cache_alloc(GFP_ATOMIC);
 	if (skp->smk_netlabel.cache != NULL) {
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 7aa7ea38f627..e65497a5c095 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3720,11 +3720,12 @@ static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap,
 	if ((sap->flags & NETLBL_SECATTR_CACHE) != 0)
 		return (struct smack_known *)sap->cache->data;
 
+	/*
+	 * Looks like a fallback, which gives us a secid.
+	 */
 	if ((sap->flags & NETLBL_SECATTR_SECID) != 0)
-		/*
-		 * Looks like a fallback, which gives us a secid.
-		 */
-		return smack_from_secid(sap->attr.secid);
+		return smack_from_secid(
+				sap->attr.lsmblob.secid[smack_lsmid.slot]);
 
 	if ((sap->flags & NETLBL_SECATTR_MLS_LVL) != 0) {
 		/*
@@ -4701,7 +4702,7 @@ struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
 	.lbs_superblock = sizeof(struct superblock_smack),
 };
 
-static struct lsm_id smack_lsmid __lsm_ro_after_init = {
+struct lsm_id smack_lsmid __lsm_ro_after_init = {
 	.lsm  = "smack",
 	.slot = LSMBLOB_NEEDED
 };
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 22ded2c26089..e592e10397af 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -1140,6 +1140,7 @@ static void smk_net4addr_insert(struct smk_net4addr *new)
 static ssize_t smk_write_net4addr(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos)
 {
+	struct lsmblob lsmblob;
 	struct smk_net4addr *snp;
 	struct sockaddr_in newname;
 	char *smack;
@@ -1271,10 +1272,13 @@ static ssize_t smk_write_net4addr(struct file *file, const char __user *buf,
 	 * this host so that incoming packets get labeled.
 	 * but only if we didn't get the special CIPSO option
 	 */
-	if (rc == 0 && skp != NULL)
+	if (rc == 0 && skp != NULL) {
+		lsmblob_init(&lsmblob, 0);
+		lsmblob.secid[smack_lsmid.slot] = snp->smk_label->smk_secid;
 		rc = netlbl_cfg_unlbl_static_add(&init_net, NULL,
-			&snp->smk_host, &snp->smk_mask, PF_INET,
-			snp->smk_label->smk_secid, &audit_info);
+			&snp->smk_host, &snp->smk_mask, PF_INET, &lsmblob,
+			&audit_info);
+	}
 
 	if (rc == 0)
 		rc = count;
-- 
2.29.2

[PATCH v26 20/25] LSM: Verify LSM display sanity in binder

[Casey Schaufler]

Verify that the tasks on the ends of a binder transaction
use the same "interface_lsm" security module. This prevents
confusion of security "contexts".

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 security/security.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/security/security.c b/security/security.c
index 1e441c3491b5..d1e9a54e22b4 100644
--- a/security/security.c
+++ b/security/security.c
@@ -857,9 +857,38 @@ int security_binder_set_context_mgr(struct task_struct *mgr)
 	return call_int_hook(binder_set_context_mgr, 0, mgr);
 }
 
+/**
+ * security_binder_transaction - Binder driver transaction check
+ * @from: source of the transaction
+ * @to: destination of the transaction
+ *
+ * Verify that the tasks have the same LSM "display", then
+ * call the security module hooks.
+ *
+ * Returns -EINVAL if the displays don't match, or the
+ * result of the security module checks.
+ */
 int security_binder_transaction(struct task_struct *from,
 				struct task_struct *to)
 {
+	int from_ilsm = lsm_task_ilsm(from);
+	int to_ilsm = lsm_task_ilsm(to);
+
+	/*
+	 * If the ilsm is LSMBLOB_INVALID the first module that has
+	 * an entry is used. This will be in the 0 slot.
+	 *
+	 * This is currently only required if the server has requested
+	 * peer contexts, but it would be unwieldly to have too much of
+	 * the binder driver detail here.
+	 */
+	if (from_ilsm == LSMBLOB_INVALID)
+		from_ilsm = 0;
+	if (to_ilsm == LSMBLOB_INVALID)
+		to_ilsm = 0;
+	if (from_ilsm != to_ilsm)
+		return -EINVAL;
+
 	return call_int_hook(binder_transaction, 0, from, to);
 }
 
-- 
2.29.2

[PATCH v26 21/25] audit: add support for non-syscall auxiliary records

[Casey Schaufler]

Standalone audit records have the timestamp and serial number generated
on the fly and as such are unique, making them standalone.  This new
function audit_alloc_local() generates a local audit context that will
be used only for a standalone record and its auxiliary record(s).  The
context is discarded immediately after the local associated records are
produced.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-audit@redhat.com
To: Richard Guy Briggs <rgb@redhat.com>
---
 include/linux/audit.h |  8 ++++++++
 kernel/audit.h        |  1 +
 kernel/auditsc.c      | 33 ++++++++++++++++++++++++++++-----
 3 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 418a485af114..97cd7471e572 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -289,6 +289,8 @@ static inline int audit_signal_info(int sig, struct task_struct *t)
 				/* Public API */
 extern int  audit_alloc(struct task_struct *task);
 extern void __audit_free(struct task_struct *task);
+extern struct audit_context *audit_alloc_local(gfp_t gfpflags);
+extern void audit_free_context(struct audit_context *context);
 extern void __audit_syscall_entry(int major, unsigned long a0, unsigned long a1,
 				  unsigned long a2, unsigned long a3);
 extern void __audit_syscall_exit(int ret_success, long ret_value);
@@ -552,6 +554,12 @@ static inline void audit_log_nfcfg(const char *name, u8 af,
 extern int audit_n_rules;
 extern int audit_signals;
 #else /* CONFIG_AUDITSYSCALL */
++static inline struct audit_context *audit_alloc_local(gfp_t gfpflags)
+{
+	return NULL;
+}
+static inline void audit_free_context(struct audit_context *context)
+{ }
 static inline int audit_alloc(struct task_struct *task)
 {
 	return 0;
diff --git a/kernel/audit.h b/kernel/audit.h
index 23a85a470121..27ef690afd30 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -99,6 +99,7 @@ struct audit_proctitle {
 struct audit_context {
 	int		    dummy;	/* must be the first element */
 	int		    in_syscall;	/* 1 if task is in a syscall */
+	bool		    local;	/* local context needed */
 	enum audit_state    state, current_state;
 	unsigned int	    serial;     /* serial number for record */
 	int		    major;      /* syscall number */
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 67da23f6bebd..d4e061f95da8 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -925,11 +925,13 @@ static inline void audit_free_aux(struct audit_context *context)
 	}
 }
 
-static inline struct audit_context *audit_alloc_context(enum audit_state state)
+static inline struct audit_context *audit_alloc_context(enum audit_state state,
+							gfp_t gfpflags)
 {
 	struct audit_context *context;
 
-	context = kzalloc(sizeof(*context), GFP_KERNEL);
+	/* We can be called in atomic context via audit_tg() */
+	context = kzalloc(sizeof(*context), gfpflags);
 	if (!context)
 		return NULL;
 	context->state = state;
@@ -965,7 +967,8 @@ int audit_alloc(struct task_struct *tsk)
 		return 0;
 	}
 
-	if (!(context = audit_alloc_context(state))) {
+	context = audit_alloc_context(state, GFP_KERNEL);
+	if (!context) {
 		kfree(key);
 		audit_log_lost("out of memory in audit_alloc");
 		return -ENOMEM;
@@ -977,8 +980,27 @@ int audit_alloc(struct task_struct *tsk)
 	return 0;
 }
 
-static inline void audit_free_context(struct audit_context *context)
+struct audit_context *audit_alloc_local(gfp_t gfpflags)
 {
+	struct audit_context *context = NULL;
+
+	context = audit_alloc_context(AUDIT_RECORD_CONTEXT, gfpflags);
+	if (!context) {
+		audit_log_lost("out of memory in audit_alloc_local");
+		goto out;
+	}
+	context->serial = audit_serial();
+	ktime_get_coarse_real_ts64(&context->ctime);
+	context->local = true;
+out:
+	return context;
+}
+EXPORT_SYMBOL(audit_alloc_local);
+
+void audit_free_context(struct audit_context *context)
+{
+	if (!context)
+		return;
 	audit_free_module(context);
 	audit_free_names(context);
 	unroll_tree_refs(context, NULL, 0);
@@ -989,6 +1011,7 @@ static inline void audit_free_context(struct audit_context *context)
 	audit_proctitle_free(context);
 	kfree(context);
 }
+EXPORT_SYMBOL(audit_free_context);
 
 static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 				 kuid_t auid, kuid_t uid,
@@ -2210,7 +2233,7 @@ EXPORT_SYMBOL_GPL(__audit_inode_child);
 int auditsc_get_stamp(struct audit_context *ctx,
 		       struct timespec64 *t, unsigned int *serial)
 {
-	if (!ctx->in_syscall)
+	if (!ctx->in_syscall && !ctx->local)
 		return 0;
 	if (!ctx->serial)
 		ctx->serial = audit_serial();
-- 
2.29.2

Re: [PATCH v26 21/25] audit: add support for non-syscall auxiliary records

[Paul Moore]

On Thu, May 13, 2021 at 4:31 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
>
> Standalone audit records have the timestamp and serial number generated
> on the fly and as such are unique, making them standalone.  This new
> function audit_alloc_local() generates a local audit context that will
> be used only for a standalone record and its auxiliary record(s).  The
> context is discarded immediately after the local associated records are
> produced.
>
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> Cc: linux-audit@redhat.com
> To: Richard Guy Briggs <rgb@redhat.com>
> ---
>  include/linux/audit.h |  8 ++++++++
>  kernel/audit.h        |  1 +
>  kernel/auditsc.c      | 33 ++++++++++++++++++++++++++++-----
>  3 files changed, 37 insertions(+), 5 deletions(-)

At some point I suspect we will need to add filtering for these
"local" records, but that is a problem for another day.

Acked-by: Paul Moore <paul@paul-moore.com>


--
paul moore
www.paul-moore.com

[PATCH v26 22/25] Audit: Add new record for multiple process LSM attributes

[Casey Schaufler]

Create a new audit record type to contain the subject information
when there are multiple security modules that require such data.
This record is linked with the same timestamp and serial number
using the audit_alloc_local() mechanism.
The record is produced only in cases where there is more than one
security module with a process "context".
In cases where this record is produced the subj= fields of
other records in the audit event will be set to "subj=?".

An example of the MAC_TASK_CONTEXTS (1420) record is:

        type=UNKNOWN[1420]
        msg=audit(1600880931.832:113)
        subj_apparmor==unconfined
        subj_smack=_

There will be a subj_$LSM= entry for each security module
LSM that supports the secid_to_secctx and secctx_to_secid
hooks. The BPF security module implements secid/secctx
translation hooks, so it has to be considered to provide a
secctx even though it may not actually do so.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
To: paul@paul-moore.com
To: linux-audit@redhat.com
To: rgb@redhat.com
Cc: netdev@vger.kernel.org
---
 drivers/android/binder.c                |  2 +-
 include/linux/audit.h                   | 24 ++++++++
 include/linux/security.h                | 16 ++++-
 include/net/netlabel.h                  |  3 +-
 include/net/scm.h                       |  2 +-
 include/net/xfrm.h                      | 13 +++-
 include/uapi/linux/audit.h              |  1 +
 kernel/audit.c                          | 80 ++++++++++++++++++-------
 kernel/audit.h                          |  3 +
 kernel/auditfilter.c                    |  6 +-
 kernel/auditsc.c                        | 75 ++++++++++++++++++++---
 net/ipv4/ip_sockglue.c                  |  2 +-
 net/netfilter/nf_conntrack_netlink.c    |  4 +-
 net/netfilter/nf_conntrack_standalone.c |  2 +-
 net/netfilter/nfnetlink_queue.c         |  2 +-
 net/netlabel/netlabel_domainhash.c      |  4 +-
 net/netlabel/netlabel_unlabeled.c       | 24 ++++----
 net/netlabel/netlabel_user.c            | 20 ++++---
 net/netlabel/netlabel_user.h            |  6 +-
 net/xfrm/xfrm_policy.c                  | 10 ++--
 net/xfrm/xfrm_state.c                   | 20 ++++---
 security/integrity/ima/ima_api.c        |  7 ++-
 security/integrity/integrity_audit.c    |  6 +-
 security/security.c                     | 46 +++++++++-----
 security/smack/smackfs.c                |  3 +-
 25 files changed, 274 insertions(+), 107 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index f2a27bbbbe4d..7818c0fe0f38 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2722,7 +2722,7 @@ static void binder_transaction(struct binder_proc *proc,
 		 * case well anyway.
 		 */
 		security_task_getsecid_obj(proc->tsk, &blob);
-		ret = security_secid_to_secctx(&blob, &lsmctx);
+		ret = security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_DISPLAY);
 		if (ret) {
 			return_error = BR_FAILED_REPLY;
 			return_error_param = ret;
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 97cd7471e572..229cd71fbf09 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -164,6 +164,8 @@ extern struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp
 extern __printf(2, 3)
 void audit_log_format(struct audit_buffer *ab, const char *fmt, ...);
 extern void		    audit_log_end(struct audit_buffer *ab);
+extern void		    audit_log_end_local(struct audit_buffer *ab,
+						struct audit_context *context);
 extern bool		    audit_string_contains_control(const char *string,
 							  size_t len);
 extern void		    audit_log_n_hex(struct audit_buffer *ab,
@@ -188,6 +190,7 @@ extern void		    audit_log_lost(const char *message);
 
 extern int audit_log_task_context(struct audit_buffer *ab);
 extern void audit_log_task_info(struct audit_buffer *ab);
+extern void audit_log_lsm(struct audit_context *context);
 
 extern int		    audit_update_lsm_rules(void);
 
@@ -226,6 +229,9 @@ void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
 { }
 static inline void audit_log_end(struct audit_buffer *ab)
 { }
+static inline void audit_log_end_local(struct audit_buffer *ab,
+				       struct audit_context *context)
+{ }
 static inline void audit_log_n_hex(struct audit_buffer *ab,
 				   const unsigned char *buf, size_t len)
 { }
@@ -252,6 +258,8 @@ static inline int audit_log_task_context(struct audit_buffer *ab)
 }
 static inline void audit_log_task_info(struct audit_buffer *ab)
 { }
+static void audit_log_lsm(struct audit_context *context)
+{ }
 
 static inline kuid_t audit_get_loginuid(struct task_struct *tsk)
 {
@@ -291,6 +299,7 @@ extern int  audit_alloc(struct task_struct *task);
 extern void __audit_free(struct task_struct *task);
 extern struct audit_context *audit_alloc_local(gfp_t gfpflags);
 extern void audit_free_context(struct audit_context *context);
+extern void audit_free_local(struct audit_context *context);
 extern void __audit_syscall_entry(int major, unsigned long a0, unsigned long a1,
 				  unsigned long a2, unsigned long a3);
 extern void __audit_syscall_exit(int ret_success, long ret_value);
@@ -386,6 +395,19 @@ static inline void audit_ptrace(struct task_struct *t)
 		__audit_ptrace(t);
 }
 
+static inline struct audit_context *audit_alloc_for_lsm(gfp_t gfp)
+{
+	struct audit_context *context = audit_context();
+
+	if (context)
+		return context;
+
+	if (lsm_multiple_contexts())
+		return audit_alloc_local(gfp);
+
+	return NULL;
+}
+
 				/* Private API (for audit.c only) */
 extern void __audit_ipc_obj(struct kern_ipc_perm *ipcp);
 extern void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mode);
@@ -560,6 +582,8 @@ extern int audit_signals;
 }
 static inline void audit_free_context(struct audit_context *context)
 { }
+static inline void audit_free_local(struct audit_context *context)
+{ }
 static inline int audit_alloc(struct task_struct *task)
 {
 	return 0;
diff --git a/include/linux/security.h b/include/linux/security.h
index 0129400ff6e9..ddab456e93d3 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -182,6 +182,8 @@ struct lsmblob {
 #define LSMBLOB_INVALID		-1	/* Not a valid LSM slot number */
 #define LSMBLOB_NEEDED		-2	/* Slot requested on initialization */
 #define LSMBLOB_NOT_NEEDED	-3	/* Slot not requested */
+#define LSMBLOB_DISPLAY		-4	/* Use the "display" slot */
+#define LSMBLOB_FIRST		-5	/* Use the default "display" slot */
 
 /**
  * lsmblob_init - initialize an lsmblob structure
@@ -248,6 +250,15 @@ static inline u32 lsmblob_value(const struct lsmblob *blob)
 	return 0;
 }
 
+static inline bool lsm_multiple_contexts(void)
+{
+#ifdef CONFIG_SECURITY
+	return lsm_slot_to_name(1) != NULL;
+#else
+	return false;
+#endif
+}
+
 /* These functions are in security/commoncap.c */
 extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
 		       int cap, unsigned int opts);
@@ -578,7 +589,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 			 size_t size);
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
-int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp);
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp,
+			     int display);
 int security_secctx_to_secid(const char *secdata, u32 seclen,
 			     struct lsmblob *blob);
 void security_release_secctx(struct lsmcontext *cp);
@@ -1433,7 +1445,7 @@ static inline int security_ismaclabel(const char *name)
 }
 
 static inline int security_secid_to_secctx(struct lsmblob *blob,
-					   struct lsmcontext *cp)
+					   struct lsmcontext *cp, int display)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/include/net/netlabel.h b/include/net/netlabel.h
index 73fc25b4042b..9bc1f969a25d 100644
--- a/include/net/netlabel.h
+++ b/include/net/netlabel.h
@@ -97,7 +97,8 @@ struct calipso_doi;
 
 /* NetLabel audit information */
 struct netlbl_audit {
-	u32 secid;
+	struct audit_context *localcontext;
+	struct lsmblob lsmdata;
 	kuid_t loginuid;
 	unsigned int sessionid;
 };
diff --git a/include/net/scm.h b/include/net/scm.h
index b77a52f93389..f4d567d4885e 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -101,7 +101,7 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
 		 * and the infrastructure will know which it is.
 		 */
 		lsmblob_init(&lb, scm->secid);
-		err = security_secid_to_secctx(&lb, &context);
+		err = security_secid_to_secctx(&lb, &context, LSMBLOB_DISPLAY);
 
 		if (!err) {
 			put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, context.len,
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index c58a6d4eb610..f8ad20d34498 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -669,13 +669,22 @@ struct xfrm_spi_skb_cb {
 #define XFRM_SPI_SKB_CB(__skb) ((struct xfrm_spi_skb_cb *)&((__skb)->cb[0]))
 
 #ifdef CONFIG_AUDITSYSCALL
-static inline struct audit_buffer *xfrm_audit_start(const char *op)
+static inline struct audit_buffer *xfrm_audit_start(const char *op,
+						    struct audit_context **lac)
 {
+	struct audit_context *context;
 	struct audit_buffer *audit_buf = NULL;
 
 	if (audit_enabled == AUDIT_OFF)
 		return NULL;
-	audit_buf = audit_log_start(audit_context(), GFP_ATOMIC,
+	context = audit_context();
+	if (lac != NULL) {
+		if (lsm_multiple_contexts() && context == NULL)
+			context = audit_alloc_local(GFP_ATOMIC);
+		*lac = context;
+	}
+
+	audit_buf = audit_log_start(context, GFP_ATOMIC,
 				    AUDIT_MAC_IPSEC_EVENT);
 	if (audit_buf == NULL)
 		return NULL;
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index cd2d8279a5e4..2a63720e56f6 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -139,6 +139,7 @@
 #define AUDIT_MAC_UNLBL_STCDEL	1417	/* NetLabel: del a static label */
 #define AUDIT_MAC_CALIPSO_ADD	1418	/* NetLabel: add CALIPSO DOI entry */
 #define AUDIT_MAC_CALIPSO_DEL	1419	/* NetLabel: del CALIPSO DOI entry */
+#define AUDIT_MAC_TASK_CONTEXTS	1420	/* Multiple LSM contexts */
 
 #define AUDIT_FIRST_KERN_ANOM_MSG   1700
 #define AUDIT_LAST_KERN_ANOM_MSG    1799
diff --git a/kernel/audit.c b/kernel/audit.c
index 841123390d41..60c027d7759c 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -386,10 +386,12 @@ void audit_log_lost(const char *message)
 static int audit_log_config_change(char *function_name, u32 new, u32 old,
 				   int allow_changes)
 {
+	struct audit_context *context;
 	struct audit_buffer *ab;
 	int rc = 0;
 
-	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
+	context = audit_alloc_for_lsm(GFP_KERNEL);
+	ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
 	if (unlikely(!ab))
 		return rc;
 	audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
@@ -398,7 +400,7 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old,
 	if (rc)
 		allow_changes = 0; /* Something weird, deny request */
 	audit_log_format(ab, " res=%d", allow_changes);
-	audit_log_end(ab);
+	audit_log_end_local(ab, context);
 	return rc;
 }
 
@@ -1072,12 +1074,6 @@ static void audit_log_common_recv_msg(struct audit_context *context,
 	audit_log_task_context(*ab);
 }
 
-static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
-					   u16 msg_type)
-{
-	audit_log_common_recv_msg(NULL, ab, msg_type);
-}
-
 int is_audit_feature_set(int i)
 {
 	return af.features & AUDIT_FEATURE_TO_MASK(i);
@@ -1110,6 +1106,7 @@ static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature
 	audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
 			 audit_feature_names[which], !!old_feature, !!new_feature,
 			 !!old_lock, !!new_lock, res);
+	audit_log_lsm(ab->ctx);
 	audit_log_end(ab);
 }
 
@@ -1190,6 +1187,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	struct audit_buffer	*ab;
 	u16			msg_type = nlh->nlmsg_type;
 	struct audit_sig_info   *sig_data;
+	struct audit_context	*lcontext;
 
 	err = audit_netlink_ok(skb, msg_type);
 	if (err)
@@ -1357,7 +1355,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 				if (err)
 					break;
 			}
-			audit_log_user_recv_msg(&ab, msg_type);
+			lcontext = audit_alloc_for_lsm(GFP_KERNEL);
+			audit_log_common_recv_msg(lcontext, &ab, msg_type);
 			if (msg_type != AUDIT_USER_TTY) {
 				/* ensure NULL termination */
 				str[data_len - 1] = '\0';
@@ -1370,7 +1369,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 					data_len--;
 				audit_log_n_untrustedstring(ab, str, data_len);
 			}
-			audit_log_end(ab);
+			audit_log_end_local(ab, lcontext);
 		}
 		break;
 	case AUDIT_ADD_RULE:
@@ -1378,13 +1377,14 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		if (data_len < sizeof(struct audit_rule_data))
 			return -EINVAL;
 		if (audit_enabled == AUDIT_LOCKED) {
-			audit_log_common_recv_msg(audit_context(), &ab,
+			lcontext = audit_alloc_for_lsm(GFP_KERNEL);
+			audit_log_common_recv_msg(lcontext, &ab,
 						  AUDIT_CONFIG_CHANGE);
 			audit_log_format(ab, " op=%s audit_enabled=%d res=0",
 					 msg_type == AUDIT_ADD_RULE ?
 						"add_rule" : "remove_rule",
 					 audit_enabled);
-			audit_log_end(ab);
+			audit_log_end_local(ab, lcontext);
 			return -EPERM;
 		}
 		err = audit_rule_change(msg_type, seq, data, data_len);
@@ -1394,10 +1394,10 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		break;
 	case AUDIT_TRIM:
 		audit_trim_trees();
-		audit_log_common_recv_msg(audit_context(), &ab,
-					  AUDIT_CONFIG_CHANGE);
+		lcontext = audit_alloc_for_lsm(GFP_KERNEL);
+		audit_log_common_recv_msg(lcontext, &ab, AUDIT_CONFIG_CHANGE);
 		audit_log_format(ab, " op=trim res=1");
-		audit_log_end(ab);
+		audit_log_end_local(ab, lcontext);
 		break;
 	case AUDIT_MAKE_EQUIV: {
 		void *bufp = data;
@@ -1425,6 +1425,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		/* OK, here comes... */
 		err = audit_tag_tree(old, new);
 
+		lcontext = audit_alloc_for_lsm(GFP_KERNEL);
 		audit_log_common_recv_msg(audit_context(), &ab,
 					  AUDIT_CONFIG_CHANGE);
 		audit_log_format(ab, " op=make_equiv old=");
@@ -1432,7 +1433,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		audit_log_format(ab, " new=");
 		audit_log_untrustedstring(ab, new);
 		audit_log_format(ab, " res=%d", !err);
-		audit_log_end(ab);
+		audit_log_end_local(ab, lcontext);
 		kfree(old);
 		kfree(new);
 		break;
@@ -1443,7 +1444,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 
 		if (lsmblob_is_set(&audit_sig_lsm)) {
 			err = security_secid_to_secctx(&audit_sig_lsm,
-						       &context);
+						       &context, LSMBLOB_FIRST);
 			if (err)
 				return err;
 		}
@@ -1498,13 +1499,14 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		old.enabled = t & AUDIT_TTY_ENABLE;
 		old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
 
+		lcontext = audit_alloc_for_lsm(GFP_KERNEL);
 		audit_log_common_recv_msg(audit_context(), &ab,
 					  AUDIT_CONFIG_CHANGE);
 		audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
 				 " old-log_passwd=%d new-log_passwd=%d res=%d",
 				 old.enabled, s.enabled, old.log_passwd,
 				 s.log_passwd, !err);
-		audit_log_end(ab);
+		audit_log_end_local(ab, lcontext);
 		break;
 	}
 	default:
@@ -1550,6 +1552,7 @@ static void audit_receive(struct sk_buff  *skb)
 /* Log information about who is connecting to the audit multicast socket */
 static void audit_log_multicast(int group, const char *op, int err)
 {
+	struct audit_context *context;
 	const struct cred *cred;
 	struct tty_struct *tty;
 	char comm[sizeof(current->comm)];
@@ -1558,7 +1561,8 @@ static void audit_log_multicast(int group, const char *op, int err)
 	if (!audit_enabled)
 		return;
 
-	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER);
+	context = audit_alloc_for_lsm(GFP_KERNEL);
+	ab = audit_log_start(context, GFP_KERNEL, AUDIT_EVENT_LISTENER);
 	if (!ab)
 		return;
 
@@ -1576,7 +1580,7 @@ static void audit_log_multicast(int group, const char *op, int err)
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_d_path_exe(ab, current->mm); /* exe= */
 	audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err);
-	audit_log_end(ab);
+	audit_log_end_local(ab, context);
 }
 
 /* Run custom bind function on netlink socket group connect or bind requests. */
@@ -2138,7 +2142,19 @@ int audit_log_task_context(struct audit_buffer *ab)
 	if (!lsmblob_is_set(&blob))
 		return 0;
 
-	error = security_secid_to_secctx(&blob, &context);
+	/*
+	 * If there is more than one security module that has a
+	 * subject "context" it's necessary to put the subject data
+	 * into a separate record to maintain compatibility.
+	 */
+	if (lsm_multiple_contexts()) {
+		if (ab->ctx)
+			ab->ctx->lsm = blob;
+		audit_log_format(ab, " subj=?");
+		return 0;
+	}
+
+	error = security_secid_to_secctx(&blob, &context, LSMBLOB_FIRST);
 	if (error) {
 		if (error != -EINVAL)
 			goto error_path;
@@ -2224,6 +2240,7 @@ void audit_log_task_info(struct audit_buffer *ab)
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
 	audit_log_d_path_exe(ab, current->mm);
 	audit_log_task_context(ab);
+	audit_log_lsm(ab->ctx);
 }
 EXPORT_SYMBOL(audit_log_task_info);
 
@@ -2274,6 +2291,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
 				   unsigned int oldsessionid,
 				   unsigned int sessionid, int rc)
 {
+	struct audit_context *context;
 	struct audit_buffer *ab;
 	uid_t uid, oldloginuid, loginuid;
 	struct tty_struct *tty;
@@ -2281,7 +2299,8 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
 	if (!audit_enabled)
 		return;
 
-	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
+	context = audit_alloc_for_lsm(GFP_KERNEL);
+	ab = audit_log_start(context, GFP_KERNEL, AUDIT_LOGIN);
 	if (!ab)
 		return;
 
@@ -2296,7 +2315,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
 			 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
 			 oldsessionid, sessionid, !rc);
 	audit_put_tty(tty);
-	audit_log_end(ab);
+	audit_log_end_local(ab, context);
 }
 
 /**
@@ -2396,6 +2415,21 @@ void audit_log_end(struct audit_buffer *ab)
 	audit_buffer_free(ab);
 }
 
+/**
+ * audit_log_end_local - end one audit record with local context
+ * @ab: the audit_buffer
+ * @context: the local context
+ *
+ * Emit an LSM context record if appropriate, then end the audit event
+ * in the usual way.
+ */
+void audit_log_end_local(struct audit_buffer *ab, struct audit_context *context)
+{
+	audit_log_end(ab);
+	audit_log_lsm_common(context);
+	audit_free_local(context);
+}
+
 /**
  * audit_log - Log an audit record
  * @ctx: audit context
diff --git a/kernel/audit.h b/kernel/audit.h
index 27ef690afd30..5ad0c6819aa8 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -100,6 +100,7 @@ struct audit_context {
 	int		    dummy;	/* must be the first element */
 	int		    in_syscall;	/* 1 if task is in a syscall */
 	bool		    local;	/* local context needed */
+	bool		    lsmdone;	/* multiple security reported */
 	enum audit_state    state, current_state;
 	unsigned int	    serial;     /* serial number for record */
 	int		    major;      /* syscall number */
@@ -131,6 +132,7 @@ struct audit_context {
 	kgid_t		    gid, egid, sgid, fsgid;
 	unsigned long	    personality;
 	int		    arch;
+	struct lsmblob	    lsm;
 
 	pid_t		    target_pid;
 	kuid_t		    target_auid;
@@ -201,6 +203,7 @@ struct audit_context {
 extern bool audit_ever_enabled;
 
 extern void audit_log_session_info(struct audit_buffer *ab);
+extern void audit_log_lsm_common(struct audit_context *context);
 
 extern int auditd_test_task(struct task_struct *task);
 
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 1ba14a7a38f7..be59ca46b0a2 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1098,12 +1098,14 @@ static void audit_list_rules(int seq, struct sk_buff_head *q)
 /* Log rule additions and removals */
 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
 {
+	struct audit_context *context;
 	struct audit_buffer *ab;
 
 	if (!audit_enabled)
 		return;
 
-	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
+	context = audit_alloc_for_lsm(GFP_KERNEL);
+	ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
 	if (!ab)
 		return;
 	audit_log_session_info(ab);
@@ -1111,7 +1113,7 @@ static void audit_log_rule_change(char *action, struct audit_krule *rule, int re
 	audit_log_format(ab, " op=%s", action);
 	audit_log_key(ab, rule->filterkey);
 	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
-	audit_log_end(ab);
+	audit_log_end_local(ab, context);
 }
 
 /**
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index d4e061f95da8..55509faf5341 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -940,6 +940,7 @@ static inline struct audit_context *audit_alloc_context(enum audit_state state,
 	INIT_LIST_HEAD(&context->names_list);
 	context->fds[0] = -1;
 	context->return_valid = AUDITSC_INVALID;
+	context->lsmdone = false;
 	return context;
 }
 
@@ -987,12 +988,11 @@ struct audit_context *audit_alloc_local(gfp_t gfpflags)
 	context = audit_alloc_context(AUDIT_RECORD_CONTEXT, gfpflags);
 	if (!context) {
 		audit_log_lost("out of memory in audit_alloc_local");
-		goto out;
+		return NULL;
 	}
 	context->serial = audit_serial();
 	ktime_get_coarse_real_ts64(&context->ctime);
 	context->local = true;
-out:
 	return context;
 }
 EXPORT_SYMBOL(audit_alloc_local);
@@ -1013,6 +1013,13 @@ void audit_free_context(struct audit_context *context)
 }
 EXPORT_SYMBOL(audit_free_context);
 
+void audit_free_local(struct audit_context *context)
+{
+	if (context && context->local)
+		audit_free_context(context);
+}
+EXPORT_SYMBOL(audit_free_local);
+
 static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 				 kuid_t auid, kuid_t uid,
 				 unsigned int sessionid,
@@ -1030,7 +1037,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
 	if (lsmblob_is_set(blob)) {
-		if (security_secid_to_secctx(blob, &lsmctx)) {
+		if (security_secid_to_secctx(blob, &lsmctx, LSMBLOB_FIRST)) {
 			audit_log_format(ab, " obj=(none)");
 			rc = 1;
 		} else {
@@ -1275,7 +1282,8 @@ static void show_special(struct audit_context *context, int *call_panic)
 			struct lsmblob blob;
 
 			lsmblob_init(&blob, osid);
-			if (security_secid_to_secctx(&blob, &lsmcxt)) {
+			if (security_secid_to_secctx(&blob, &lsmcxt,
+						     LSMBLOB_FIRST)) {
 				audit_log_format(ab, " osid=%u", osid);
 				*call_panic = 1;
 			} else {
@@ -1430,7 +1438,7 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 		struct lsmcontext lsmctx;
 
 		lsmblob_init(&blob, n->osid);
-		if (security_secid_to_secctx(&blob, &lsmctx)) {
+		if (security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_FIRST)) {
 			audit_log_format(ab, " osid=%u", n->osid);
 			if (call_panic)
 				*call_panic = 2;
@@ -1504,6 +1512,47 @@ static void audit_log_proctitle(void)
 	audit_log_end(ab);
 }
 
+void audit_log_lsm_common(struct audit_context *context)
+{
+	struct audit_buffer *ab;
+	struct lsmcontext lsmdata;
+	bool sep = false;
+	int error;
+	int i;
+
+	if (!lsm_multiple_contexts() || context == NULL ||
+	    !lsmblob_is_set(&context->lsm))
+		return;
+
+	ab = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_TASK_CONTEXTS);
+	if (!ab)
+		return; /* audit_panic or being filtered */
+
+	for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+		if (context->lsm.secid[i] == 0)
+			continue;
+		error = security_secid_to_secctx(&context->lsm, &lsmdata, i);
+		if (error && error != -EINVAL) {
+			audit_panic("error in audit_log_lsm");
+			return;
+		}
+
+		audit_log_format(ab, "%ssubj_%s=%s", sep ? " " : "",
+				 lsm_slot_to_name(i), lsmdata.context);
+		sep = true;
+
+		security_release_secctx(&lsmdata);
+	}
+	audit_log_end(ab);
+	context->lsmdone = true;
+}
+
+void audit_log_lsm(struct audit_context *context)
+{
+	if (!context->lsmdone)
+		audit_log_lsm_common(context);
+}
+
 static void audit_log_exit(void)
 {
 	int i, call_panic = 0;
@@ -1538,6 +1587,8 @@ static void audit_log_exit(void)
 	audit_log_key(ab, context->filterkey);
 	audit_log_end(ab);
 
+	audit_log_lsm(context);
+
 	for (aux = context->aux; aux; aux = aux->next) {
 
 		ab = audit_log_start(context, GFP_KERNEL, aux->type);
@@ -1628,6 +1679,8 @@ static void audit_log_exit(void)
 
 	audit_log_proctitle();
 
+	audit_log_lsm(context);
+
 	/* Send end of event record to help user space know we are finished */
 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_EOE);
 	if (ab)
@@ -2619,10 +2672,12 @@ void __audit_ntp_log(const struct audit_ntp_data *ad)
 void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries,
 		       enum audit_nfcfgop op, gfp_t gfp)
 {
+	struct audit_context *context;
 	struct audit_buffer *ab;
 	char comm[sizeof(current->comm)];
 
-	ab = audit_log_start(audit_context(), gfp, AUDIT_NETFILTER_CFG);
+	context = audit_alloc_for_lsm(GFP_KERNEL);
+	ab = audit_log_start(context, gfp, AUDIT_NETFILTER_CFG);
 	if (!ab)
 		return;
 	audit_log_format(ab, "table=%s family=%u entries=%u op=%s",
@@ -2632,7 +2687,7 @@ void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries,
 	audit_log_task_context(ab); /* subj= */
 	audit_log_format(ab, " comm=");
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
-	audit_log_end(ab);
+	audit_log_end_local(ab, context);
 }
 EXPORT_SYMBOL_GPL(__audit_log_nfcfg);
 
@@ -2667,6 +2722,7 @@ static void audit_log_task(struct audit_buffer *ab)
  */
 void audit_core_dumps(long signr)
 {
+	struct audit_context *context;
 	struct audit_buffer *ab;
 
 	if (!audit_enabled)
@@ -2675,12 +2731,13 @@ void audit_core_dumps(long signr)
 	if (signr == SIGQUIT)	/* don't care for those */
 		return;
 
-	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_ABEND);
+	context = audit_alloc_for_lsm(GFP_KERNEL);
+	ab = audit_log_start(context, GFP_KERNEL, AUDIT_ANOM_ABEND);
 	if (unlikely(!ab))
 		return;
 	audit_log_task(ab);
 	audit_log_format(ab, " sig=%ld res=1", signr);
-	audit_log_end(ab);
+	audit_log_end_local(ab, context);
 }
 
 /**
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index ae073b642fa7..5c0029a3a595 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -140,7 +140,7 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
 		return;
 
 	lsmblob_init(&lb, secid);
-	err = security_secid_to_secctx(&lb, &context);
+	err = security_secid_to_secctx(&lb, &context, LSMBLOB_DISPLAY);
 	if (err)
 		return;
 
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 215d3f9e9715..60539221e023 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -344,7 +344,7 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 	 * security_secid_to_secctx() will know which security module
 	 * to use to create the secctx.  */
 	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, &context);
+	ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY);
 	if (ret)
 		return 0;
 
@@ -655,7 +655,7 @@ static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
 	struct lsmblob blob;
 	struct lsmcontext context;
 
-	ret = security_secid_to_secctx(&blob, &context);
+	ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY);
 	if (ret)
 		return 0;
 
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index df6043d1bc22..861106a5f605 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -177,7 +177,7 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 	struct lsmcontext context;
 
 	lsmblob_init(&blob, ct->secmark);
-	ret = security_secid_to_secctx(&blob, &context);
+	ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY);
 	if (ret)
 		return;
 
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index bf8db099090b..90ecf03b35ba 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -316,7 +316,7 @@ static void nfqnl_get_sk_secctx(struct sk_buff *skb, struct lsmcontext *context)
 		 * blob. security_secid_to_secctx() will know which security
 		 * module to use to create the secctx.  */
 		lsmblob_init(&blob, skb->secmark);
-		security_secid_to_secctx(&blob, context);
+		security_secid_to_secctx(&blob, context, LSMBLOB_DISPLAY);
 	}
 
 	read_unlock_bh(&skb->sk->sk_callback_lock);
diff --git a/net/netlabel/netlabel_domainhash.c b/net/netlabel/netlabel_domainhash.c
index dc8c39f51f7d..2690a528d262 100644
--- a/net/netlabel/netlabel_domainhash.c
+++ b/net/netlabel/netlabel_domainhash.c
@@ -259,7 +259,7 @@ static void netlbl_domhsh_audit_add(struct netlbl_dom_map *entry,
 			break;
 		}
 		audit_log_format(audit_buf, " res=%u", result == 0 ? 1 : 0);
-		audit_log_end(audit_buf);
+		audit_log_end_local(audit_buf, audit_info->localcontext);
 	}
 }
 
@@ -614,7 +614,7 @@ int netlbl_domhsh_remove_entry(struct netlbl_dom_map *entry,
 		audit_log_format(audit_buf,
 				 " nlbl_domain=%s res=1",
 				 entry->domain ? entry->domain : "(default)");
-		audit_log_end(audit_buf);
+		audit_log_end_local(audit_buf, audit_info->localcontext);
 	}
 
 	switch (entry->def.type) {
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 0ce9bee43dd3..380eeffd8e00 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -437,13 +437,14 @@ int netlbl_unlhsh_add(struct net *net,
 unlhsh_add_return:
 	rcu_read_unlock();
 	if (audit_buf != NULL) {
-		if (security_secid_to_secctx(lsmblob, &context) == 0) {
+		if (security_secid_to_secctx(lsmblob, &context,
+					     LSMBLOB_FIRST) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0);
-		audit_log_end(audit_buf);
+		audit_log_end_local(audit_buf, audit_info->localcontext);
 	}
 	return ret_val;
 }
@@ -492,13 +493,14 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 		if (dev != NULL)
 			dev_put(dev);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
+		    security_secid_to_secctx(&entry->lsmblob, &context,
+					     LSMBLOB_FIRST) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
-		audit_log_end(audit_buf);
+		audit_log_end_local(audit_buf, audit_info->localcontext);
 	}
 
 	if (entry == NULL)
@@ -552,13 +554,14 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 		if (dev != NULL)
 			dev_put(dev);
 		if (entry != NULL &&
-		    security_secid_to_secctx(&entry->lsmblob, &context) == 0) {
+		    security_secid_to_secctx(&entry->lsmblob, &context,
+					     LSMBLOB_FIRST) == 0) {
 			audit_log_format(audit_buf, " sec_obj=%s",
 					 context.context);
 			security_release_secctx(&context);
 		}
 		audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
-		audit_log_end(audit_buf);
+		audit_log_end_local(audit_buf, audit_info->localcontext);
 	}
 
 	if (entry == NULL)
@@ -741,7 +744,7 @@ static void netlbl_unlabel_acceptflg_set(u8 value,
 	if (audit_buf != NULL) {
 		audit_log_format(audit_buf,
 				 " unlbl_accept=%u old=%u", value, old_val);
-		audit_log_end(audit_buf);
+		audit_log_end_local(audit_buf, audit_info->localcontext);
 	}
 }
 
@@ -1122,7 +1125,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
 		lsmb = (struct lsmblob *)&addr6->lsmblob;
 	}
 
-	ret_val = security_secid_to_secctx(lsmb, &context);
+	ret_val = security_secid_to_secctx(lsmb, &context, LSMBLOB_FIRST);
 	if (ret_val != 0)
 		goto list_cb_failure;
 	ret_val = nla_put(cb_arg->skb,
@@ -1528,14 +1531,11 @@ int __init netlbl_unlabel_defconf(void)
 	int ret_val;
 	struct netlbl_dom_map *entry;
 	struct netlbl_audit audit_info;
-	struct lsmblob blob;
 
 	/* Only the kernel is allowed to call this function and the only time
 	 * it is called is at bootup before the audit subsystem is reporting
 	 * messages so don't worry to much about these values. */
-	security_task_getsecid_subj(current, &blob);
-	/* scaffolding until audit_info.secid is converted */
-	audit_info.secid = blob.secid[0];
+	security_task_getsecid_subj(current, &audit_info.lsmdata);
 	audit_info.loginuid = GLOBAL_ROOT_UID;
 	audit_info.sessionid = 0;
 
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 951ba0639d20..90a18b245380 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -83,14 +83,17 @@ int __init netlbl_netlink_init(void)
 struct audit_buffer *netlbl_audit_start_common(int type,
 					       struct netlbl_audit *audit_info)
 {
+	struct audit_context *audit_ctx;
 	struct audit_buffer *audit_buf;
 	struct lsmcontext context;
-	struct lsmblob blob;
 
 	if (audit_enabled == AUDIT_OFF)
 		return NULL;
 
-	audit_buf = audit_log_start(audit_context(), GFP_ATOMIC, type);
+	audit_ctx = audit_alloc_for_lsm(GFP_ATOMIC);
+	audit_info->localcontext = audit_ctx;
+
+	audit_buf = audit_log_start(audit_ctx, GFP_ATOMIC, type);
 	if (audit_buf == NULL)
 		return NULL;
 
@@ -98,11 +101,14 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 			 from_kuid(&init_user_ns, audit_info->loginuid),
 			 audit_info->sessionid);
 
-	lsmblob_init(&blob, audit_info->secid);
-	if (audit_info->secid != 0 &&
-	    security_secid_to_secctx(&blob, &context) == 0) {
-		audit_log_format(audit_buf, " subj=%s", context.context);
-		security_release_secctx(&context);
+	if (lsmblob_is_set(&audit_info->lsmdata)) {
+		if (!lsm_multiple_contexts() &&
+		    security_secid_to_secctx(&audit_info->lsmdata, &context,
+					     LSMBLOB_FIRST) == 0) {
+			audit_log_format(audit_buf, " subj=%s",
+					 context.context);
+			security_release_secctx(&context);
+		}
 	}
 
 	return audit_buf;
diff --git a/net/netlabel/netlabel_user.h b/net/netlabel/netlabel_user.h
index 11f6da93f31b..bc1f0cd824d5 100644
--- a/net/netlabel/netlabel_user.h
+++ b/net/netlabel/netlabel_user.h
@@ -34,11 +34,7 @@
 static inline void netlbl_netlink_auditinfo(struct sk_buff *skb,
 					    struct netlbl_audit *audit_info)
 {
-	struct lsmblob blob;
-
-	security_task_getsecid_subj(current, &blob);
-	/* scaffolding until secid is converted */
-	audit_info->secid = blob.secid[0];
+	security_task_getsecid_subj(current, &audit_info->lsmdata);
 	audit_info->loginuid = audit_get_loginuid(current);
 	audit_info->sessionid = audit_get_sessionid(current);
 }
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index ce500f847b99..a4d554214d4b 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -4173,30 +4173,32 @@ static void xfrm_audit_common_policyinfo(struct xfrm_policy *xp,
 
 void xfrm_audit_policy_add(struct xfrm_policy *xp, int result, bool task_valid)
 {
+	struct audit_context *context;
 	struct audit_buffer *audit_buf;
 
-	audit_buf = xfrm_audit_start("SPD-add");
+	audit_buf = xfrm_audit_start("SPD-add", &context);
 	if (audit_buf == NULL)
 		return;
 	xfrm_audit_helper_usrinfo(task_valid, audit_buf);
 	audit_log_format(audit_buf, " res=%u", result);
 	xfrm_audit_common_policyinfo(xp, audit_buf);
-	audit_log_end(audit_buf);
+	audit_log_end_local(audit_buf, context);
 }
 EXPORT_SYMBOL_GPL(xfrm_audit_policy_add);
 
 void xfrm_audit_policy_delete(struct xfrm_policy *xp, int result,
 			      bool task_valid)
 {
+	struct audit_context *context;
 	struct audit_buffer *audit_buf;
 
-	audit_buf = xfrm_audit_start("SPD-delete");
+	audit_buf = xfrm_audit_start("SPD-delete", &context);
 	if (audit_buf == NULL)
 		return;
 	xfrm_audit_helper_usrinfo(task_valid, audit_buf);
 	audit_log_format(audit_buf, " res=%u", result);
 	xfrm_audit_common_policyinfo(xp, audit_buf);
-	audit_log_end(audit_buf);
+	audit_log_end_local(audit_buf, context);
 }
 EXPORT_SYMBOL_GPL(xfrm_audit_policy_delete);
 #endif
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 4496f7efa220..a1fd0e122be8 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -2747,29 +2747,31 @@ static void xfrm_audit_helper_pktinfo(struct sk_buff *skb, u16 family,
 
 void xfrm_audit_state_add(struct xfrm_state *x, int result, bool task_valid)
 {
+	struct audit_context *context;
 	struct audit_buffer *audit_buf;
 
-	audit_buf = xfrm_audit_start("SAD-add");
+	audit_buf = xfrm_audit_start("SAD-add", &context);
 	if (audit_buf == NULL)
 		return;
 	xfrm_audit_helper_usrinfo(task_valid, audit_buf);
 	xfrm_audit_helper_sainfo(x, audit_buf);
 	audit_log_format(audit_buf, " res=%u", result);
-	audit_log_end(audit_buf);
+	audit_log_end_local(audit_buf, context);
 }
 EXPORT_SYMBOL_GPL(xfrm_audit_state_add);
 
 void xfrm_audit_state_delete(struct xfrm_state *x, int result, bool task_valid)
 {
+	struct audit_context *context;
 	struct audit_buffer *audit_buf;
 
-	audit_buf = xfrm_audit_start("SAD-delete");
+	audit_buf = xfrm_audit_start("SAD-delete", &context);
 	if (audit_buf == NULL)
 		return;
 	xfrm_audit_helper_usrinfo(task_valid, audit_buf);
 	xfrm_audit_helper_sainfo(x, audit_buf);
 	audit_log_format(audit_buf, " res=%u", result);
-	audit_log_end(audit_buf);
+	audit_log_end_local(audit_buf, context);
 }
 EXPORT_SYMBOL_GPL(xfrm_audit_state_delete);
 
@@ -2779,7 +2781,7 @@ void xfrm_audit_state_replay_overflow(struct xfrm_state *x,
 	struct audit_buffer *audit_buf;
 	u32 spi;
 
-	audit_buf = xfrm_audit_start("SA-replay-overflow");
+	audit_buf = xfrm_audit_start("SA-replay-overflow", NULL);
 	if (audit_buf == NULL)
 		return;
 	xfrm_audit_helper_pktinfo(skb, x->props.family, audit_buf);
@@ -2797,7 +2799,7 @@ void xfrm_audit_state_replay(struct xfrm_state *x,
 	struct audit_buffer *audit_buf;
 	u32 spi;
 
-	audit_buf = xfrm_audit_start("SA-replayed-pkt");
+	audit_buf = xfrm_audit_start("SA-replayed-pkt", NULL);
 	if (audit_buf == NULL)
 		return;
 	xfrm_audit_helper_pktinfo(skb, x->props.family, audit_buf);
@@ -2812,7 +2814,7 @@ void xfrm_audit_state_notfound_simple(struct sk_buff *skb, u16 family)
 {
 	struct audit_buffer *audit_buf;
 
-	audit_buf = xfrm_audit_start("SA-notfound");
+	audit_buf = xfrm_audit_start("SA-notfound", NULL);
 	if (audit_buf == NULL)
 		return;
 	xfrm_audit_helper_pktinfo(skb, family, audit_buf);
@@ -2826,7 +2828,7 @@ void xfrm_audit_state_notfound(struct sk_buff *skb, u16 family,
 	struct audit_buffer *audit_buf;
 	u32 spi;
 
-	audit_buf = xfrm_audit_start("SA-notfound");
+	audit_buf = xfrm_audit_start("SA-notfound", NULL);
 	if (audit_buf == NULL)
 		return;
 	xfrm_audit_helper_pktinfo(skb, family, audit_buf);
@@ -2844,7 +2846,7 @@ void xfrm_audit_state_icvfail(struct xfrm_state *x,
 	__be32 net_spi;
 	__be32 net_seq;
 
-	audit_buf = xfrm_audit_start("SA-icv-failure");
+	audit_buf = xfrm_audit_start("SA-icv-failure", NULL);
 	if (audit_buf == NULL)
 		return;
 	xfrm_audit_helper_pktinfo(skb, x->props.family, audit_buf);
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 691f68d478f1..8e7c660b9b01 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -342,6 +342,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
 void ima_audit_measurement(struct integrity_iint_cache *iint,
 			   const unsigned char *filename)
 {
+	struct audit_context *context;
 	struct audit_buffer *ab;
 	char *hash;
 	const char *algo_name = hash_algo_name[iint->ima_hash->algo];
@@ -358,8 +359,8 @@ void ima_audit_measurement(struct integrity_iint_cache *iint,
 		hex_byte_pack(hash + (i * 2), iint->ima_hash->digest[i]);
 	hash[i * 2] = '\0';
 
-	ab = audit_log_start(audit_context(), GFP_KERNEL,
-			     AUDIT_INTEGRITY_RULE);
+	context = audit_alloc_for_lsm(GFP_KERNEL);
+	ab = audit_log_start(context, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
 	if (!ab)
 		goto out;
 
@@ -368,7 +369,7 @@ void ima_audit_measurement(struct integrity_iint_cache *iint,
 	audit_log_format(ab, " hash=\"%s:%s\"", algo_name, hash);
 
 	audit_log_task_info(ab);
-	audit_log_end(ab);
+	audit_log_end_local(ab, context);
 
 	iint->flags |= IMA_AUDITED;
 out:
diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c
index 29220056207f..b38163c43659 100644
--- a/security/integrity/integrity_audit.c
+++ b/security/integrity/integrity_audit.c
@@ -38,13 +38,15 @@ void integrity_audit_message(int audit_msgno, struct inode *inode,
 			     const char *cause, int result, int audit_info,
 			     int errno)
 {
+	struct audit_context *context;
 	struct audit_buffer *ab;
 	char name[TASK_COMM_LEN];
 
 	if (!integrity_audit_info && audit_info == 1)	/* Skip info messages */
 		return;
 
-	ab = audit_log_start(audit_context(), GFP_KERNEL, audit_msgno);
+	context = audit_alloc_for_lsm(GFP_KERNEL);
+	ab = audit_log_start(context, GFP_KERNEL, audit_msgno);
 	audit_log_format(ab, "pid=%d uid=%u auid=%u ses=%u",
 			 task_pid_nr(current),
 			 from_kuid(&init_user_ns, current_uid()),
@@ -63,5 +65,5 @@ void integrity_audit_message(int audit_msgno, struct inode *inode,
 		audit_log_format(ab, " ino=%lu", inode->i_ino);
 	}
 	audit_log_format(ab, " res=%d errno=%d", !result, errno);
-	audit_log_end(ab);
+	audit_log_end_local(ab, context);
 }
diff --git a/security/security.c b/security/security.c
index d1e9a54e22b4..bb4c7f6c62ec 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2307,7 +2307,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
 		hlist_for_each_entry(hp, &security_hook_heads.setprocattr,
 				     list) {
 			rc = hp->hook.setprocattr(name, value, size);
-			if (rc < 0)
+			if (rc < 0 && rc != -EINVAL)
 				return rc;
 		}
 
@@ -2352,13 +2352,31 @@ int security_ismaclabel(const char *name)
 }
 EXPORT_SYMBOL(security_ismaclabel);
 
-int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp)
+int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp,
+			     int ilsm)
 {
 	struct security_hook_list *hp;
-	int ilsm = lsm_task_ilsm(current);
 
 	memset(cp, 0, sizeof(*cp));
 
+	/*
+	 * ilsm either is the slot number use for formatting
+	 * or an instruction on which relative slot to use.
+	 */
+	if (ilsm == LSMBLOB_DISPLAY)
+		ilsm = lsm_task_ilsm(current);
+	else if (ilsm == LSMBLOB_FIRST)
+		ilsm = LSMBLOB_INVALID;
+	else if (ilsm < 0) {
+		WARN_ONCE(true,
+			"LSM: %s unknown interface LSM\n", __func__);
+		ilsm = LSMBLOB_INVALID;
+	} else if (ilsm >= lsm_slot) {
+		WARN_ONCE(true,
+			"LSM: %s invalid interface LSM\n", __func__);
+		ilsm = LSMBLOB_INVALID;
+	}
+
 	hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
@@ -2388,7 +2406,7 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
 			return hp->hook.secctx_to_secid(secdata, seclen,
 						&blob->secid[hp->lsmid->slot]);
 	}
-	return 0;
+	return -EOPNOTSUPP;
 }
 EXPORT_SYMBOL(security_secctx_to_secid);
 
@@ -2882,23 +2900,17 @@ int security_key_getsecurity(struct key *key, char **_buffer)
 int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule)
 {
 	struct security_hook_list *hp;
-	bool one_is_good = false;
-	int rc = 0;
-	int trc;
+	int ilsm = lsm_task_ilsm(current);
 
 	hlist_for_each_entry(hp, &security_hook_heads.audit_rule_init, list) {
 		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
 			continue;
-		trc = hp->hook.audit_rule_init(field, op, rulestr,
-					       &lsmrule[hp->lsmid->slot]);
-		if (trc == 0)
-			one_is_good = true;
-		else
-			rc = trc;
+		if (ilsm != LSMBLOB_INVALID && ilsm != hp->lsmid->slot)
+			continue;
+		return hp->hook.audit_rule_init(field, op, rulestr,
+						&lsmrule[hp->lsmid->slot]);
 	}
-	if (one_is_good)
-		return 0;
-	return rc;
+	return 0;
 }
 
 int security_audit_rule_known(struct audit_krule *krule)
@@ -2930,6 +2942,8 @@ int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
 			continue;
 		if (lsmrule[hp->lsmid->slot] == NULL)
 			continue;
+		if (lsmrule[hp->lsmid->slot] == NULL)
+			continue;
 		rc = hp->hook.audit_rule_match(blob->secid[hp->lsmid->slot],
 					       field, op,
 					       &lsmrule[hp->lsmid->slot]);
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index e592e10397af..d56e55c04aa4 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -185,7 +185,8 @@ static void smk_netlabel_audit_set(struct netlbl_audit *nap)
 
 	nap->loginuid = audit_get_loginuid(current);
 	nap->sessionid = audit_get_sessionid(current);
-	nap->secid = skp->smk_secid;
+	lsmblob_init(&nap->lsmdata, 0);
+	nap->lsmdata.secid[smack_lsmid.slot] = skp->smk_secid;
 }
 
 /*
-- 
2.29.2

Re: [PATCH v26 22/25] Audit: Add new record for multiple process LSM attributes

[Paul Moore]

On Thu, May 13, 2021 at 4:32 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
>
> Create a new audit record type to contain the subject information
> when there are multiple security modules that require such data.
> This record is linked with the same timestamp and serial number
> using the audit_alloc_local() mechanism.

The record is linked with the other associated records into a single
event, it doesn't matter if it gets the timestamp/serial from
audit_alloc_local() or an existing audit event, e.g. ongoing syscall.

> The record is produced only in cases where there is more than one
> security module with a process "context".
> In cases where this record is produced the subj= fields of
> other records in the audit event will be set to "subj=?".
>
> An example of the MAC_TASK_CONTEXTS (1420) record is:
>
>         type=UNKNOWN[1420]
>         msg=audit(1600880931.832:113)
>         subj_apparmor==unconfined

It should be just a single "=" in the line above.

>         subj_smack=_
>
> There will be a subj_$LSM= entry for each security module
> LSM that supports the secid_to_secctx and secctx_to_secid
> hooks. The BPF security module implements secid/secctx
> translation hooks, so it has to be considered to provide a
> secctx even though it may not actually do so.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> To: paul@paul-moore.com
> To: linux-audit@redhat.com
> To: rgb@redhat.com
> Cc: netdev@vger.kernel.org
> ---
>  drivers/android/binder.c                |  2 +-
>  include/linux/audit.h                   | 24 ++++++++
>  include/linux/security.h                | 16 ++++-
>  include/net/netlabel.h                  |  3 +-
>  include/net/scm.h                       |  2 +-
>  include/net/xfrm.h                      | 13 +++-
>  include/uapi/linux/audit.h              |  1 +
>  kernel/audit.c                          | 80 ++++++++++++++++++-------
>  kernel/audit.h                          |  3 +
>  kernel/auditfilter.c                    |  6 +-
>  kernel/auditsc.c                        | 75 ++++++++++++++++++++---
>  net/ipv4/ip_sockglue.c                  |  2 +-
>  net/netfilter/nf_conntrack_netlink.c    |  4 +-
>  net/netfilter/nf_conntrack_standalone.c |  2 +-
>  net/netfilter/nfnetlink_queue.c         |  2 +-
>  net/netlabel/netlabel_domainhash.c      |  4 +-
>  net/netlabel/netlabel_unlabeled.c       | 24 ++++----
>  net/netlabel/netlabel_user.c            | 20 ++++---
>  net/netlabel/netlabel_user.h            |  6 +-
>  net/xfrm/xfrm_policy.c                  | 10 ++--
>  net/xfrm/xfrm_state.c                   | 20 ++++---
>  security/integrity/ima/ima_api.c        |  7 ++-
>  security/integrity/integrity_audit.c    |  6 +-
>  security/security.c                     | 46 +++++++++-----
>  security/smack/smackfs.c                |  3 +-
>  25 files changed, 274 insertions(+), 107 deletions(-)

...

> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index 97cd7471e572..229cd71fbf09 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -386,6 +395,19 @@ static inline void audit_ptrace(struct task_struct *t)
>                 __audit_ptrace(t);
>  }
>
> +static inline struct audit_context *audit_alloc_for_lsm(gfp_t gfp)
> +{
> +       struct audit_context *context = audit_context();
> +
> +       if (context)
> +               return context;
> +
> +       if (lsm_multiple_contexts())
> +               return audit_alloc_local(gfp);
> +
> +       return NULL;
> +}

See my other comments, but this seems wrong at face value.  The
additional LSM record should happen as part of the existing audit log
functions.

> diff --git a/include/linux/security.h b/include/linux/security.h
> index 0129400ff6e9..ddab456e93d3 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -182,6 +182,8 @@ struct lsmblob {
>  #define LSMBLOB_INVALID                -1      /* Not a valid LSM slot number */
>  #define LSMBLOB_NEEDED         -2      /* Slot requested on initialization */
>  #define LSMBLOB_NOT_NEEDED     -3      /* Slot not requested */
> +#define LSMBLOB_DISPLAY                -4      /* Use the "display" slot */
> +#define LSMBLOB_FIRST          -5      /* Use the default "display" slot */
>
>  /**
>   * lsmblob_init - initialize an lsmblob structure
> @@ -248,6 +250,15 @@ static inline u32 lsmblob_value(const struct lsmblob *blob)
>         return 0;
>  }
>
> +static inline bool lsm_multiple_contexts(void)
> +{
> +#ifdef CONFIG_SECURITY
> +       return lsm_slot_to_name(1) != NULL;
> +#else
> +       return false;
> +#endif
> +}
> +
>  /* These functions are in security/commoncap.c */
>  extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
>                        int cap, unsigned int opts);
> @@ -578,7 +589,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
>                          size_t size);
>  int security_netlink_send(struct sock *sk, struct sk_buff *skb);
>  int security_ismaclabel(const char *name);
> -int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp);
> +int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp,
> +                            int display);
>  int security_secctx_to_secid(const char *secdata, u32 seclen,
>                              struct lsmblob *blob);
>  void security_release_secctx(struct lsmcontext *cp);
> @@ -1433,7 +1445,7 @@ static inline int security_ismaclabel(const char *name)
>  }
>
>  static inline int security_secid_to_secctx(struct lsmblob *blob,
> -                                          struct lsmcontext *cp)
> +                                          struct lsmcontext *cp, int display)
>  {
>         return -EOPNOTSUPP;
>  }
> diff --git a/include/net/netlabel.h b/include/net/netlabel.h
> index 73fc25b4042b..9bc1f969a25d 100644
> --- a/include/net/netlabel.h
> +++ b/include/net/netlabel.h
> @@ -97,7 +97,8 @@ struct calipso_doi;
>
>  /* NetLabel audit information */
>  struct netlbl_audit {
> -       u32 secid;
> +       struct audit_context *localcontext;
> +       struct lsmblob lsmdata;
>         kuid_t loginuid;
>         unsigned int sessionid;
>  };
> diff --git a/include/net/scm.h b/include/net/scm.h
> index b77a52f93389..f4d567d4885e 100644
> --- a/include/net/scm.h
> +++ b/include/net/scm.h
> @@ -101,7 +101,7 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
>                  * and the infrastructure will know which it is.
>                  */
>                 lsmblob_init(&lb, scm->secid);
> -               err = security_secid_to_secctx(&lb, &context);
> +               err = security_secid_to_secctx(&lb, &context, LSMBLOB_DISPLAY);
>
>                 if (!err) {
>                         put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, context.len,
> diff --git a/include/net/xfrm.h b/include/net/xfrm.h
> index c58a6d4eb610..f8ad20d34498 100644
> --- a/include/net/xfrm.h
> +++ b/include/net/xfrm.h
> @@ -669,13 +669,22 @@ struct xfrm_spi_skb_cb {
>  #define XFRM_SPI_SKB_CB(__skb) ((struct xfrm_spi_skb_cb *)&((__skb)->cb[0]))
>
>  #ifdef CONFIG_AUDITSYSCALL
> -static inline struct audit_buffer *xfrm_audit_start(const char *op)
> +static inline struct audit_buffer *xfrm_audit_start(const char *op,
> +                                                   struct audit_context **lac)
>  {
> +       struct audit_context *context;
>         struct audit_buffer *audit_buf = NULL;
>
>         if (audit_enabled == AUDIT_OFF)
>                 return NULL;
> -       audit_buf = audit_log_start(audit_context(), GFP_ATOMIC,
> +       context = audit_context();
> +       if (lac != NULL) {
> +               if (lsm_multiple_contexts() && context == NULL)
> +                       context = audit_alloc_local(GFP_ATOMIC);
> +               *lac = context;
> +       }

Okay, we've got a disconnect here regarding "audit contexts" and
"local contexts", skip down below where I attempt to explain things a
little more but basically if there is a place that uses this pattern:

  audit_log_start(audit_context(), ...);

... you don't need, or want, a "local context".  You might need a
local context if you see the following pattern:

  audit_log_start(NULL, ...);

The "local context" idea is a hack and should be avoided whenever
possible; if you have an existing audit context from a syscall, or
something else, you *really* should use it ... or have a *really* good
explanation as to why you can not.

> +       audit_buf = audit_log_start(context, GFP_ATOMIC,
>                                     AUDIT_MAC_IPSEC_EVENT);
>         if (audit_buf == NULL)
>                 return NULL;

> diff --git a/kernel/audit.c b/kernel/audit.c
> index 841123390d41..60c027d7759c 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -386,10 +386,12 @@ void audit_log_lost(const char *message)
>  static int audit_log_config_change(char *function_name, u32 new, u32 old,
>                                    int allow_changes)
>  {
> +       struct audit_context *context;
>         struct audit_buffer *ab;
>         int rc = 0;
>
> -       ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
> +       context = audit_alloc_for_lsm(GFP_KERNEL);
> +       ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE);

Use the existing context, don't create your own, it breaks the record
associations in the audit event stream.

>         if (unlikely(!ab))
>                 return rc;
>         audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
> @@ -398,7 +400,7 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old,
>         if (rc)
>                 allow_changes = 0; /* Something weird, deny request */
>         audit_log_format(ab, " res=%d", allow_changes);
> -       audit_log_end(ab);
> +       audit_log_end_local(ab, context);

More on this below, but we really should just use audit_log_end(),
"local contexts" are not special, the are regular audit contexts ...
although if they are used properly (limited scope) you do need to free
them when you are done.

>         return rc;
>  }
>

> @@ -1357,7 +1355,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
>                                 if (err)
>                                         break;
>                         }
> -                       audit_log_user_recv_msg(&ab, msg_type);
> +                       lcontext = audit_alloc_for_lsm(GFP_KERNEL);
> +                       audit_log_common_recv_msg(lcontext, &ab, msg_type);

Same.

>                         if (msg_type != AUDIT_USER_TTY) {
>                                 /* ensure NULL termination */
>                                 str[data_len - 1] = '\0';
> @@ -1370,7 +1369,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
>                                         data_len--;
>                                 audit_log_n_untrustedstring(ab, str, data_len);
>                         }
> -                       audit_log_end(ab);
> +                       audit_log_end_local(ab, lcontext);

Same.

>                 }
>                 break;
>         case AUDIT_ADD_RULE:
> @@ -1378,13 +1377,14 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
>                 if (data_len < sizeof(struct audit_rule_data))
>                         return -EINVAL;
>                 if (audit_enabled == AUDIT_LOCKED) {
> -                       audit_log_common_recv_msg(audit_context(), &ab,
> +                       lcontext = audit_alloc_for_lsm(GFP_KERNEL);
> +                       audit_log_common_recv_msg(lcontext, &ab,
>                                                   AUDIT_CONFIG_CHANGE);
>                         audit_log_format(ab, " op=%s audit_enabled=%d res=0",
>                                          msg_type == AUDIT_ADD_RULE ?
>                                                 "add_rule" : "remove_rule",
>                                          audit_enabled);
> -                       audit_log_end(ab);
> +                       audit_log_end_local(ab, lcontext);

Same.  I'm going to stop calling these out, I think you get the idea.

> @@ -2396,6 +2415,21 @@ void audit_log_end(struct audit_buffer *ab)
>         audit_buffer_free(ab);
>  }
>
> +/**
> + * audit_log_end_local - end one audit record with local context
> + * @ab: the audit_buffer
> + * @context: the local context
> + *
> + * Emit an LSM context record if appropriate, then end the audit event
> + * in the usual way.
> + */
> +void audit_log_end_local(struct audit_buffer *ab, struct audit_context *context)
> +{
> +       audit_log_end(ab);
> +       audit_log_lsm_common(context);
> +       audit_free_local(context);
> +}

Eeesh, no, not this please.

First, some background on audit contexts and the idea of a "local
context" as we have been using it in the audit container ID work,
which is where this originated.  An audit context contains a few
things, but likely the most important for this discussion is the audit
event timestamp and serial number (I may refer to this combo as just a
"timestamp" in the future); this timestamp/serial is shared across all
of the audit records that make up this audit event, linking them
together.  A shared timestamp is what allows you to group an open()
SYSCALL record with the PATH record that provides the file's pathname
info.

While there are some exceptions in the current code, most audit events
occur as a result of a syscall, and their audit context in this case
is the syscall's audit context (see the open() example above), but
there are some cases being discussed where we have an audit event that
does not occur as a result of a syscall but there is a need to group
multiple audit records together in a single event.  This is where the
"local context" comes into play, it allows us to create an audit
context outside of a syscall and share that context across multiple
audit records, allowing the records to share a timestamp/serial and
grouping them together as a single audit event in the audit stream.

While a function like audit_alloc_local() make sense, there really
shouldn't be an audit_log_end_local() function, the normal
audit_log_end() function should be used.

Does that make sense?

> diff --git a/kernel/audit.h b/kernel/audit.h
> index 27ef690afd30..5ad0c6819aa8 100644
> --- a/kernel/audit.h
> +++ b/kernel/audit.h
> @@ -100,6 +100,7 @@ struct audit_context {
>         int                 dummy;      /* must be the first element */
>         int                 in_syscall; /* 1 if task is in a syscall */
>         bool                local;      /* local context needed */
> +       bool                lsmdone;    /* multiple security reported */

"lsmdone" doesn't seem consistent with the comment, how about
"lsm_multi" or something similar?

>         enum audit_state    state, current_state;
>         unsigned int        serial;     /* serial number for record */
>         int                 major;      /* syscall number */

> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index d4e061f95da8..55509faf5341 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -1013,6 +1013,13 @@ void audit_free_context(struct audit_context *context)
>  }
>  EXPORT_SYMBOL(audit_free_context);
>
> +void audit_free_local(struct audit_context *context)
> +{
> +       if (context && context->local)
> +               audit_free_context(context);
> +}
> +EXPORT_SYMBOL(audit_free_local);

We don't need this function, just use audit_free_context().  A "local
context" is the same as a non-local context; what makes a context
"local" is the scope of the audit context (local function scope vs
syscall scope) and nothing else.

> @@ -1504,6 +1512,47 @@ static void audit_log_proctitle(void)
>         audit_log_end(ab);
>  }
>
> +void audit_log_lsm_common(struct audit_context *context)
> +{
> +       struct audit_buffer *ab;
> +       struct lsmcontext lsmdata;
> +       bool sep = false;
> +       int error;
> +       int i;
> +
> +       if (!lsm_multiple_contexts() || context == NULL ||
> +           !lsmblob_is_set(&context->lsm))
> +               return;
> +
> +       ab = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_TASK_CONTEXTS);
> +       if (!ab)
> +               return; /* audit_panic or being filtered */

We should be consistent with our use of audit_panic() when we bail on
error; we use it below, but not here - why?

> +       for (i = 0; i < LSMBLOB_ENTRIES; i++) {
> +               if (context->lsm.secid[i] == 0)
> +                       continue;
> +               error = security_secid_to_secctx(&context->lsm, &lsmdata, i);
> +               if (error && error != -EINVAL) {
> +                       audit_panic("error in audit_log_lsm");
> +                       return;
> +               }
> +
> +               audit_log_format(ab, "%ssubj_%s=%s", sep ? " " : "",
> +                                lsm_slot_to_name(i), lsmdata.context);
> +               sep = true;
> +               security_release_secctx(&lsmdata);
> +       }
> +       audit_log_end(ab);
> +       context->lsmdone = true;

Maybe I missed it, but why do we need this flag?

> +}
> +
> +void audit_log_lsm(struct audit_context *context)
> +{
> +       if (!context->lsmdone)
> +               audit_log_lsm_common(context);
> +}

I think I was distracted with the local context issue and I've lost
track of the details here, perhaps it's best to fix the local context
issue first (that should be a big change to this patch) and then we
can take another look.


--
paul moore
www.paul-moore.com

Re: [PATCH v26 22/25] Audit: Add new record for multiple process LSM attributes

[Richard Guy Briggs]

On 2021-05-21 16:19, Paul Moore wrote:
> On Thu, May 13, 2021 at 4:32 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
> > Create a new audit record type to contain the subject information
> > when there are multiple security modules that require such data.
> > This record is linked with the same timestamp and serial number
> > using the audit_alloc_local() mechanism.
> 
> The record is linked with the other associated records into a single
> event, it doesn't matter if it gets the timestamp/serial from
> audit_alloc_local() or an existing audit event, e.g. ongoing syscall.

I had similar concerns this would be misunderstood...

> > The record is produced only in cases where there is more than one
> > security module with a process "context".
> > In cases where this record is produced the subj= fields of
> > other records in the audit event will be set to "subj=?".
> >
> > An example of the MAC_TASK_CONTEXTS (1420) record is:
> >
> >         type=UNKNOWN[1420]
> >         msg=audit(1600880931.832:113)
> >         subj_apparmor==unconfined
> 
> It should be just a single "=" in the line above.
> 
> >         subj_smack=_
> >
> > There will be a subj_$LSM= entry for each security module
> > LSM that supports the secid_to_secctx and secctx_to_secid
> > hooks. The BPF security module implements secid/secctx
> > translation hooks, so it has to be considered to provide a
> > secctx even though it may not actually do so.
> >
> > Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> > To: paul@paul-moore.com
> > To: linux-audit@redhat.com
> > To: rgb@redhat.com
> > Cc: netdev@vger.kernel.org
> > ---
> >  drivers/android/binder.c                |  2 +-
> >  include/linux/audit.h                   | 24 ++++++++
> >  include/linux/security.h                | 16 ++++-
> >  include/net/netlabel.h                  |  3 +-
> >  include/net/scm.h                       |  2 +-
> >  include/net/xfrm.h                      | 13 +++-
> >  include/uapi/linux/audit.h              |  1 +
> >  kernel/audit.c                          | 80 ++++++++++++++++++-------
> >  kernel/audit.h                          |  3 +
> >  kernel/auditfilter.c                    |  6 +-
> >  kernel/auditsc.c                        | 75 ++++++++++++++++++++---
> >  net/ipv4/ip_sockglue.c                  |  2 +-
> >  net/netfilter/nf_conntrack_netlink.c    |  4 +-
> >  net/netfilter/nf_conntrack_standalone.c |  2 +-
> >  net/netfilter/nfnetlink_queue.c         |  2 +-
> >  net/netlabel/netlabel_domainhash.c      |  4 +-
> >  net/netlabel/netlabel_unlabeled.c       | 24 ++++----
> >  net/netlabel/netlabel_user.c            | 20 ++++---
> >  net/netlabel/netlabel_user.h            |  6 +-
> >  net/xfrm/xfrm_policy.c                  | 10 ++--
> >  net/xfrm/xfrm_state.c                   | 20 ++++---
> >  security/integrity/ima/ima_api.c        |  7 ++-
> >  security/integrity/integrity_audit.c    |  6 +-
> >  security/security.c                     | 46 +++++++++-----
> >  security/smack/smackfs.c                |  3 +-
> >  25 files changed, 274 insertions(+), 107 deletions(-)
> 
> ...
> 
> > diff --git a/include/linux/audit.h b/include/linux/audit.h
> > index 97cd7471e572..229cd71fbf09 100644
> > --- a/include/linux/audit.h
> > +++ b/include/linux/audit.h
> > @@ -386,6 +395,19 @@ static inline void audit_ptrace(struct task_struct *t)
> >                 __audit_ptrace(t);
> >  }
> >
> > +static inline struct audit_context *audit_alloc_for_lsm(gfp_t gfp)
> > +{
> > +       struct audit_context *context = audit_context();
> > +
> > +       if (context)
> > +               return context;
> > +
> > +       if (lsm_multiple_contexts())
> > +               return audit_alloc_local(gfp);
> > +
> > +       return NULL;
> > +}
> 
> See my other comments, but this seems wrong at face value.  The
> additional LSM record should happen as part of the existing audit log
> functions.

Right.  The only time a local context should be necessary is if there is
a group of records that should be divorced from a syscall or that has no
syscall (or other similar context).

> > diff --git a/include/linux/security.h b/include/linux/security.h
> > index 0129400ff6e9..ddab456e93d3 100644
> > --- a/include/linux/security.h
> > +++ b/include/linux/security.h
> > @@ -182,6 +182,8 @@ struct lsmblob {
> >  #define LSMBLOB_INVALID                -1      /* Not a valid LSM slot number */
> >  #define LSMBLOB_NEEDED         -2      /* Slot requested on initialization */
> >  #define LSMBLOB_NOT_NEEDED     -3      /* Slot not requested */
> > +#define LSMBLOB_DISPLAY                -4      /* Use the "display" slot */
> > +#define LSMBLOB_FIRST          -5      /* Use the default "display" slot */
> >
> >  /**
> >   * lsmblob_init - initialize an lsmblob structure
> > @@ -248,6 +250,15 @@ static inline u32 lsmblob_value(const struct lsmblob *blob)
> >         return 0;
> >  }
> >
> > +static inline bool lsm_multiple_contexts(void)
> > +{
> > +#ifdef CONFIG_SECURITY
> > +       return lsm_slot_to_name(1) != NULL;
> > +#else
> > +       return false;
> > +#endif
> > +}
> > +
> >  /* These functions are in security/commoncap.c */
> >  extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
> >                        int cap, unsigned int opts);
> > @@ -578,7 +589,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
> >                          size_t size);
> >  int security_netlink_send(struct sock *sk, struct sk_buff *skb);
> >  int security_ismaclabel(const char *name);
> > -int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp);
> > +int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp,
> > +                            int display);
> >  int security_secctx_to_secid(const char *secdata, u32 seclen,
> >                              struct lsmblob *blob);
> >  void security_release_secctx(struct lsmcontext *cp);
> > @@ -1433,7 +1445,7 @@ static inline int security_ismaclabel(const char *name)
> >  }
> >
> >  static inline int security_secid_to_secctx(struct lsmblob *blob,
> > -                                          struct lsmcontext *cp)
> > +                                          struct lsmcontext *cp, int display)
> >  {
> >         return -EOPNOTSUPP;
> >  }
> > diff --git a/include/net/netlabel.h b/include/net/netlabel.h
> > index 73fc25b4042b..9bc1f969a25d 100644
> > --- a/include/net/netlabel.h
> > +++ b/include/net/netlabel.h
> > @@ -97,7 +97,8 @@ struct calipso_doi;
> >
> >  /* NetLabel audit information */
> >  struct netlbl_audit {
> > -       u32 secid;
> > +       struct audit_context *localcontext;
> > +       struct lsmblob lsmdata;
> >         kuid_t loginuid;
> >         unsigned int sessionid;
> >  };
> > diff --git a/include/net/scm.h b/include/net/scm.h
> > index b77a52f93389..f4d567d4885e 100644
> > --- a/include/net/scm.h
> > +++ b/include/net/scm.h
> > @@ -101,7 +101,7 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
> >                  * and the infrastructure will know which it is.
> >                  */
> >                 lsmblob_init(&lb, scm->secid);
> > -               err = security_secid_to_secctx(&lb, &context);
> > +               err = security_secid_to_secctx(&lb, &context, LSMBLOB_DISPLAY);
> >
> >                 if (!err) {
> >                         put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, context.len,
> > diff --git a/include/net/xfrm.h b/include/net/xfrm.h
> > index c58a6d4eb610..f8ad20d34498 100644
> > --- a/include/net/xfrm.h
> > +++ b/include/net/xfrm.h
> > @@ -669,13 +669,22 @@ struct xfrm_spi_skb_cb {
> >  #define XFRM_SPI_SKB_CB(__skb) ((struct xfrm_spi_skb_cb *)&((__skb)->cb[0]))
> >
> >  #ifdef CONFIG_AUDITSYSCALL
> > -static inline struct audit_buffer *xfrm_audit_start(const char *op)
> > +static inline struct audit_buffer *xfrm_audit_start(const char *op,
> > +                                                   struct audit_context **lac)
> >  {
> > +       struct audit_context *context;
> >         struct audit_buffer *audit_buf = NULL;
> >
> >         if (audit_enabled == AUDIT_OFF)
> >                 return NULL;
> > -       audit_buf = audit_log_start(audit_context(), GFP_ATOMIC,
> > +       context = audit_context();
> > +       if (lac != NULL) {
> > +               if (lsm_multiple_contexts() && context == NULL)
> > +                       context = audit_alloc_local(GFP_ATOMIC);
> > +               *lac = context;
> > +       }
> 
> Okay, we've got a disconnect here regarding "audit contexts" and
> "local contexts", skip down below where I attempt to explain things a
> little more but basically if there is a place that uses this pattern:
> 
>   audit_log_start(audit_context(), ...);
> 
> ... you don't need, or want, a "local context".  You might need a
> local context if you see the following pattern:
> 
>   audit_log_start(NULL, ...);
> 
> The "local context" idea is a hack and should be avoided whenever
> possible; if you have an existing audit context from a syscall, or
> something else, you *really* should use it ... or have a *really* good
> explanation as to why you can not.

Yes, what Paul said.  Examples include network events that have no
syscall related to them or a user record that isn't really related to
the syscall that produced it.

> > +       audit_buf = audit_log_start(context, GFP_ATOMIC,
> >                                     AUDIT_MAC_IPSEC_EVENT);
> >         if (audit_buf == NULL)
> >                 return NULL;
> 
> > diff --git a/kernel/audit.c b/kernel/audit.c
> > index 841123390d41..60c027d7759c 100644
> > --- a/kernel/audit.c
> > +++ b/kernel/audit.c
> > @@ -386,10 +386,12 @@ void audit_log_lost(const char *message)
> >  static int audit_log_config_change(char *function_name, u32 new, u32 old,
> >                                    int allow_changes)
> >  {
> > +       struct audit_context *context;
> >         struct audit_buffer *ab;
> >         int rc = 0;
> >
> > -       ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
> > +       context = audit_alloc_for_lsm(GFP_KERNEL);
> > +       ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
> 
> Use the existing context, don't create your own, it breaks the record
> associations in the audit event stream.

Agreed.

> >         if (unlikely(!ab))
> >                 return rc;
> >         audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
> > @@ -398,7 +400,7 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old,
> >         if (rc)
> >                 allow_changes = 0; /* Something weird, deny request */
> >         audit_log_format(ab, " res=%d", allow_changes);
> > -       audit_log_end(ab);
> > +       audit_log_end_local(ab, context);
> 
> More on this below, but we really should just use audit_log_end(),
> "local contexts" are not special, the are regular audit contexts ...
> although if they are used properly (limited scope) you do need to free
> them when you are done.

I was a bit puzzled about this before and had the same concerns.

> >         return rc;
> >  }
> >
> 
> > @@ -1357,7 +1355,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
> >                                 if (err)
> >                                         break;
> >                         }
> > -                       audit_log_user_recv_msg(&ab, msg_type);
> > +                       lcontext = audit_alloc_for_lsm(GFP_KERNEL);
> > +                       audit_log_common_recv_msg(lcontext, &ab, msg_type);
> 
> Same.
> 
> >                         if (msg_type != AUDIT_USER_TTY) {
> >                                 /* ensure NULL termination */
> >                                 str[data_len - 1] = '\0';
> > @@ -1370,7 +1369,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
> >                                         data_len--;
> >                                 audit_log_n_untrustedstring(ab, str, data_len);
> >                         }
> > -                       audit_log_end(ab);
> > +                       audit_log_end_local(ab, lcontext);
> 
> Same.
> 
> >                 }
> >                 break;
> >         case AUDIT_ADD_RULE:
> > @@ -1378,13 +1377,14 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
> >                 if (data_len < sizeof(struct audit_rule_data))
> >                         return -EINVAL;
> >                 if (audit_enabled == AUDIT_LOCKED) {
> > -                       audit_log_common_recv_msg(audit_context(), &ab,
> > +                       lcontext = audit_alloc_for_lsm(GFP_KERNEL);
> > +                       audit_log_common_recv_msg(lcontext, &ab,
> >                                                   AUDIT_CONFIG_CHANGE);
> >                         audit_log_format(ab, " op=%s audit_enabled=%d res=0",
> >                                          msg_type == AUDIT_ADD_RULE ?
> >                                                 "add_rule" : "remove_rule",
> >                                          audit_enabled);
> > -                       audit_log_end(ab);
> > +                       audit_log_end_local(ab, lcontext);
> 
> Same.  I'm going to stop calling these out, I think you get the idea.
> 
> > @@ -2396,6 +2415,21 @@ void audit_log_end(struct audit_buffer *ab)
> >         audit_buffer_free(ab);
> >  }
> >
> > +/**
> > + * audit_log_end_local - end one audit record with local context
> > + * @ab: the audit_buffer
> > + * @context: the local context
> > + *
> > + * Emit an LSM context record if appropriate, then end the audit event
> > + * in the usual way.
> > + */
> > +void audit_log_end_local(struct audit_buffer *ab, struct audit_context *context)
> > +{
> > +       audit_log_end(ab);
> > +       audit_log_lsm_common(context);
> > +       audit_free_local(context);
> > +}
> 
> Eeesh, no, not this please.

It was this that I found hard to follow and justify.

> First, some background on audit contexts and the idea of a "local
> context" as we have been using it in the audit container ID work,
> which is where this originated.  An audit context contains a few
> things, but likely the most important for this discussion is the audit
> event timestamp and serial number (I may refer to this combo as just a
> "timestamp" in the future); this timestamp/serial is shared across all
> of the audit records that make up this audit event, linking them
> together.  A shared timestamp is what allows you to group an open()
> SYSCALL record with the PATH record that provides the file's pathname
> info.

How about a "postmark"?  :-)    (Yes, timestamp works...)

> While there are some exceptions in the current code, most audit events
> occur as a result of a syscall, and their audit context in this case
> is the syscall's audit context (see the open() example above), but
> there are some cases being discussed where we have an audit event that
> does not occur as a result of a syscall but there is a need to group
> multiple audit records together in a single event.  This is where the
> "local context" comes into play, it allows us to create an audit
> context outside of a syscall and share that context across multiple
> audit records, allowing the records to share a timestamp/serial and
> grouping them together as a single audit event in the audit stream.
> 
> While a function like audit_alloc_local() make sense, there really
> shouldn't be an audit_log_end_local() function, the normal
> audit_log_end() function should be used.

Exactly.

> Does that make sense?
> 
> > diff --git a/kernel/audit.h b/kernel/audit.h
> > index 27ef690afd30..5ad0c6819aa8 100644
> > --- a/kernel/audit.h
> > +++ b/kernel/audit.h
> > @@ -100,6 +100,7 @@ struct audit_context {
> >         int                 dummy;      /* must be the first element */
> >         int                 in_syscall; /* 1 if task is in a syscall */
> >         bool                local;      /* local context needed */
> > +       bool                lsmdone;    /* multiple security reported */
> 
> "lsmdone" doesn't seem consistent with the comment, how about
> "lsm_multi" or something similar?
> 
> >         enum audit_state    state, current_state;
> >         unsigned int        serial;     /* serial number for record */
> >         int                 major;      /* syscall number */
> 
> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index d4e061f95da8..55509faf5341 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -1013,6 +1013,13 @@ void audit_free_context(struct audit_context *context)
> >  }
> >  EXPORT_SYMBOL(audit_free_context);
> >
> > +void audit_free_local(struct audit_context *context)
> > +{
> > +       if (context && context->local)
> > +               audit_free_context(context);
> > +}
> > +EXPORT_SYMBOL(audit_free_local);
> 
> We don't need this function, just use audit_free_context().  A "local
> context" is the same as a non-local context; what makes a context
> "local" is the scope of the audit context (local function scope vs
> syscall scope) and nothing else.

Agreed.

> > @@ -1504,6 +1512,47 @@ static void audit_log_proctitle(void)
> >         audit_log_end(ab);
> >  }
> >
> > +void audit_log_lsm_common(struct audit_context *context)
> > +{
> > +       struct audit_buffer *ab;
> > +       struct lsmcontext lsmdata;
> > +       bool sep = false;
> > +       int error;
> > +       int i;
> > +
> > +       if (!lsm_multiple_contexts() || context == NULL ||
> > +           !lsmblob_is_set(&context->lsm))
> > +               return;
> > +
> > +       ab = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_TASK_CONTEXTS);
> > +       if (!ab)
> > +               return; /* audit_panic or being filtered */
> 
> We should be consistent with our use of audit_panic() when we bail on
> error; we use it below, but not here - why?
> 
> > +       for (i = 0; i < LSMBLOB_ENTRIES; i++) {
> > +               if (context->lsm.secid[i] == 0)
> > +                       continue;
> > +               error = security_secid_to_secctx(&context->lsm, &lsmdata, i);
> > +               if (error && error != -EINVAL) {
> > +                       audit_panic("error in audit_log_lsm");
> > +                       return;
> > +               }
> > +
> > +               audit_log_format(ab, "%ssubj_%s=%s", sep ? " " : "",
> > +                                lsm_slot_to_name(i), lsmdata.context);
> > +               sep = true;
> > +               security_release_secctx(&lsmdata);
> > +       }
> > +       audit_log_end(ab);
> > +       context->lsmdone = true;
> 
> Maybe I missed it, but why do we need this flag?

This is partly what confused me earlier...

> > +}
> > +
> > +void audit_log_lsm(struct audit_context *context)
> > +{
> > +       if (!context->lsmdone)
> > +               audit_log_lsm_common(context);
> > +}
> 
> I think I was distracted with the local context issue and I've lost
> track of the details here, perhaps it's best to fix the local context
> issue first (that should be a big change to this patch) and then we
> can take another look.

I got distracted by the local context issues too earlier...  Sorry, this
feedback would have been more useful earlier.  I never completed that
review and got pulled off to other priorities...

> paul moore

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635

Re: [PATCH v26 22/25] Audit: Add new record for multiple process LSM attributes

[Casey Schaufler]

On 5/21/2021 1:19 PM, Paul Moore wrote:
> On Thu, May 13, 2021 at 4:32 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
>> Create a new audit record type to contain the subject information
>> when there are multiple security modules that require such data.
>> This record is linked with the same timestamp and serial number
>> using the audit_alloc_local() mechanism.
> The record is linked with the other associated records into a single
> event, it doesn't matter if it gets the timestamp/serial from
> audit_alloc_local() or an existing audit event, e.g. ongoing syscall.
>
>> The record is produced only in cases where there is more than one
>> security module with a process "context".
>> In cases where this record is produced the subj= fields of
>> other records in the audit event will be set to "subj=?".
>>
>> An example of the MAC_TASK_CONTEXTS (1420) record is:
>>
>>         type=UNKNOWN[1420]
>>         msg=audit(1600880931.832:113)
>>         subj_apparmor==unconfined
> It should be just a single "=" in the line above.

AppArmor provides the 2nd "=" as part of the subject context.
What's here is correct. I won't argue that it won't case confusion
or worse.


>>         subj_smack=_
>>
>> There will be a subj_$LSM= entry for each security module
>> LSM that supports the secid_to_secctx and secctx_to_secid
>> hooks. The BPF security module implements secid/secctx
>> translation hooks, so it has to be considered to provide a
>> secctx even though it may not actually do so.
>>
>> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
>> To: paul@paul-moore.com
>> To: linux-audit@redhat.com
>> To: rgb@redhat.com
>> Cc: netdev@vger.kernel.org
>> ---
>>  drivers/android/binder.c                |  2 +-
>>  include/linux/audit.h                   | 24 ++++++++
>>  include/linux/security.h                | 16 ++++-
>>  include/net/netlabel.h                  |  3 +-
>>  include/net/scm.h                       |  2 +-
>>  include/net/xfrm.h                      | 13 +++-
>>  include/uapi/linux/audit.h              |  1 +
>>  kernel/audit.c                          | 80 ++++++++++++++++++-------
>>  kernel/audit.h                          |  3 +
>>  kernel/auditfilter.c                    |  6 +-
>>  kernel/auditsc.c                        | 75 ++++++++++++++++++++---
>>  net/ipv4/ip_sockglue.c                  |  2 +-
>>  net/netfilter/nf_conntrack_netlink.c    |  4 +-
>>  net/netfilter/nf_conntrack_standalone.c |  2 +-
>>  net/netfilter/nfnetlink_queue.c         |  2 +-
>>  net/netlabel/netlabel_domainhash.c      |  4 +-
>>  net/netlabel/netlabel_unlabeled.c       | 24 ++++----
>>  net/netlabel/netlabel_user.c            | 20 ++++---
>>  net/netlabel/netlabel_user.h            |  6 +-
>>  net/xfrm/xfrm_policy.c                  | 10 ++--
>>  net/xfrm/xfrm_state.c                   | 20 ++++---
>>  security/integrity/ima/ima_api.c        |  7 ++-
>>  security/integrity/integrity_audit.c    |  6 +-
>>  security/security.c                     | 46 +++++++++-----
>>  security/smack/smackfs.c                |  3 +-
>>  25 files changed, 274 insertions(+), 107 deletions(-)
> ...
>
>> diff --git a/include/linux/audit.h b/include/linux/audit.h
>> index 97cd7471e572..229cd71fbf09 100644
>> --- a/include/linux/audit.h
>> +++ b/include/linux/audit.h
>> @@ -386,6 +395,19 @@ static inline void audit_ptrace(struct task_struct *t)
>>                 __audit_ptrace(t);
>>  }
>>
>> +static inline struct audit_context *audit_alloc_for_lsm(gfp_t gfp)
>> +{
>> +       struct audit_context *context = audit_context();
>> +
>> +       if (context)
>> +               return context;
>> +
>> +       if (lsm_multiple_contexts())
>> +               return audit_alloc_local(gfp);
>> +
>> +       return NULL;
>> +}
> See my other comments, but this seems wrong at face value.  The
> additional LSM record should happen as part of the existing audit log
> functions.

I'm good with that. But if you defer calling audit_alloc_local()
until you know you need it you may be in a place where you can't
associate the new context with the event. I think. I will have
another go at it.

<snip> 

> I think I was distracted with the local context issue and I've lost
> track of the details here, perhaps it's best to fix the local context
> issue first (that should be a big change to this patch) and then we
> can take another look.

I really need to move forward. I'll give allocation of local contexts
as necessary in audit_log_task_context() another shot. 

>
>
> --
> paul moore
> www.paul-moore.com

Re: [PATCH v26 22/25] Audit: Add new record for multiple process LSM attributes

[Paul Moore]

On Fri, May 21, 2021 at 6:05 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
> On 5/21/2021 1:19 PM, Paul Moore wrote:
> > On Thu, May 13, 2021 at 4:32 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
> >> Create a new audit record type to contain the subject information
> >> when there are multiple security modules that require such data.
> >> This record is linked with the same timestamp and serial number
> >> using the audit_alloc_local() mechanism.
> > The record is linked with the other associated records into a single
> > event, it doesn't matter if it gets the timestamp/serial from
> > audit_alloc_local() or an existing audit event, e.g. ongoing syscall.
> >
> >> The record is produced only in cases where there is more than one
> >> security module with a process "context".
> >> In cases where this record is produced the subj= fields of
> >> other records in the audit event will be set to "subj=?".
> >>
> >> An example of the MAC_TASK_CONTEXTS (1420) record is:
> >>
> >>         type=UNKNOWN[1420]
> >>         msg=audit(1600880931.832:113)
> >>         subj_apparmor==unconfined
> > It should be just a single "=" in the line above.
>
> AppArmor provides the 2nd "=" as part of the subject context.
> What's here is correct. I won't argue that it won't case confusion
> or worse.

Oh, wow, okay.  That needs to change at some point but I agree it's
out of scope for this patchset.  In the meantime I might suggest using
something other than AppArmor as an example here.

> >>         subj_smack=_
> >>
> >> There will be a subj_$LSM= entry for each security module
> >> LSM that supports the secid_to_secctx and secctx_to_secid
> >> hooks. The BPF security module implements secid/secctx
> >> translation hooks, so it has to be considered to provide a
> >> secctx even though it may not actually do so.
> >>
> >> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> >> To: paul@paul-moore.com
> >> To: linux-audit@redhat.com
> >> To: rgb@redhat.com
> >> Cc: netdev@vger.kernel.org
> >> ---
> >>  drivers/android/binder.c                |  2 +-
> >>  include/linux/audit.h                   | 24 ++++++++
> >>  include/linux/security.h                | 16 ++++-
> >>  include/net/netlabel.h                  |  3 +-
> >>  include/net/scm.h                       |  2 +-
> >>  include/net/xfrm.h                      | 13 +++-
> >>  include/uapi/linux/audit.h              |  1 +
> >>  kernel/audit.c                          | 80 ++++++++++++++++++-------
> >>  kernel/audit.h                          |  3 +
> >>  kernel/auditfilter.c                    |  6 +-
> >>  kernel/auditsc.c                        | 75 ++++++++++++++++++++---
> >>  net/ipv4/ip_sockglue.c                  |  2 +-
> >>  net/netfilter/nf_conntrack_netlink.c    |  4 +-
> >>  net/netfilter/nf_conntrack_standalone.c |  2 +-
> >>  net/netfilter/nfnetlink_queue.c         |  2 +-
> >>  net/netlabel/netlabel_domainhash.c      |  4 +-
> >>  net/netlabel/netlabel_unlabeled.c       | 24 ++++----
> >>  net/netlabel/netlabel_user.c            | 20 ++++---
> >>  net/netlabel/netlabel_user.h            |  6 +-
> >>  net/xfrm/xfrm_policy.c                  | 10 ++--
> >>  net/xfrm/xfrm_state.c                   | 20 ++++---
> >>  security/integrity/ima/ima_api.c        |  7 ++-
> >>  security/integrity/integrity_audit.c    |  6 +-
> >>  security/security.c                     | 46 +++++++++-----
> >>  security/smack/smackfs.c                |  3 +-
> >>  25 files changed, 274 insertions(+), 107 deletions(-)
> > ...
> >
> >> diff --git a/include/linux/audit.h b/include/linux/audit.h
> >> index 97cd7471e572..229cd71fbf09 100644
> >> --- a/include/linux/audit.h
> >> +++ b/include/linux/audit.h
> >> @@ -386,6 +395,19 @@ static inline void audit_ptrace(struct task_struct *t)
> >>                 __audit_ptrace(t);
> >>  }
> >>
> >> +static inline struct audit_context *audit_alloc_for_lsm(gfp_t gfp)
> >> +{
> >> +       struct audit_context *context = audit_context();
> >> +
> >> +       if (context)
> >> +               return context;
> >> +
> >> +       if (lsm_multiple_contexts())
> >> +               return audit_alloc_local(gfp);
> >> +
> >> +       return NULL;
> >> +}
> > See my other comments, but this seems wrong at face value.  The
> > additional LSM record should happen as part of the existing audit log
> > functions.
>
> I'm good with that. But if you defer calling audit_alloc_local()
> until you know you need it you may be in a place where you can't
> associate the new context with the event. I think. I will have
> another go at it.

I can't think of a case where you would ever not know if you need to
allocate a local context at the start.  If you are unsure, get in
touch and we can work it out.

> > I think I was distracted with the local context issue and I've lost
> > track of the details here, perhaps it's best to fix the local context
> > issue first (that should be a big change to this patch) and then we
> > can take another look.
>
> I really need to move forward. I'll give allocation of local contexts
> as necessary in audit_log_task_context() another shot.

I appreciate the desire to move forward, and while I can't speak for
everyone, I'll do my best to work with you to find a good solution.
If you get stuck or aren't sure you know how to reach me :)

As a start, I might suggest looking at some of the recent audit
container ID patchsets from Richard; while they have had some issues,
they should serve as a basic example of what we mean when we talk
about "local contexts" and how they should be used.

-- 
paul moore
www.paul-moore.com

Re: [PATCH v26 22/25] Audit: Add new record for multiple process LSM attributes

[Richard Guy Briggs]

On 2021-05-21 22:20, Paul Moore wrote:
> On Fri, May 21, 2021 at 6:05 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
> > On 5/21/2021 1:19 PM, Paul Moore wrote:
> > > On Thu, May 13, 2021 at 4:32 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
> > >> Create a new audit record type to contain the subject information
> > >> when there are multiple security modules that require such data.
> > >> This record is linked with the same timestamp and serial number
> > >> using the audit_alloc_local() mechanism.
> > > The record is linked with the other associated records into a single
> > > event, it doesn't matter if it gets the timestamp/serial from
> > > audit_alloc_local() or an existing audit event, e.g. ongoing syscall.
> > >
> > >> The record is produced only in cases where there is more than one
> > >> security module with a process "context".
> > >> In cases where this record is produced the subj= fields of
> > >> other records in the audit event will be set to "subj=?".
> > >>
> > >> An example of the MAC_TASK_CONTEXTS (1420) record is:
> > >>
> > >>         type=UNKNOWN[1420]
> > >>         msg=audit(1600880931.832:113)
> > >>         subj_apparmor==unconfined
> > > It should be just a single "=" in the line above.
> >
> > AppArmor provides the 2nd "=" as part of the subject context.
> > What's here is correct. I won't argue that it won't case confusion
> > or worse.
> 
> Oh, wow, okay.  That needs to change at some point but I agree it's
> out of scope for this patchset.  In the meantime I might suggest using
> something other than AppArmor as an example here.

Similar but not identical situation to:
	BUG: INTEGRITY_POLICY_RULE violates audit message format · Issue #113 · linux-audit/audit-kernel
	https://github.com/linux-audit/audit-kernel/issues/113

> > >>         subj_smack=_
> > >>
> > >> There will be a subj_$LSM= entry for each security module
> > >> LSM that supports the secid_to_secctx and secctx_to_secid
> > >> hooks. The BPF security module implements secid/secctx
> > >> translation hooks, so it has to be considered to provide a
> > >> secctx even though it may not actually do so.
> > >>
> > >> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> > >> To: paul@paul-moore.com
> > >> To: linux-audit@redhat.com
> > >> To: rgb@redhat.com
> > >> Cc: netdev@vger.kernel.org
> > >> ---
> > >>  drivers/android/binder.c                |  2 +-
> > >>  include/linux/audit.h                   | 24 ++++++++
> > >>  include/linux/security.h                | 16 ++++-
> > >>  include/net/netlabel.h                  |  3 +-
> > >>  include/net/scm.h                       |  2 +-
> > >>  include/net/xfrm.h                      | 13 +++-
> > >>  include/uapi/linux/audit.h              |  1 +
> > >>  kernel/audit.c                          | 80 ++++++++++++++++++-------
> > >>  kernel/audit.h                          |  3 +
> > >>  kernel/auditfilter.c                    |  6 +-
> > >>  kernel/auditsc.c                        | 75 ++++++++++++++++++++---
> > >>  net/ipv4/ip_sockglue.c                  |  2 +-
> > >>  net/netfilter/nf_conntrack_netlink.c    |  4 +-
> > >>  net/netfilter/nf_conntrack_standalone.c |  2 +-
> > >>  net/netfilter/nfnetlink_queue.c         |  2 +-
> > >>  net/netlabel/netlabel_domainhash.c      |  4 +-
> > >>  net/netlabel/netlabel_unlabeled.c       | 24 ++++----
> > >>  net/netlabel/netlabel_user.c            | 20 ++++---
> > >>  net/netlabel/netlabel_user.h            |  6 +-
> > >>  net/xfrm/xfrm_policy.c                  | 10 ++--
> > >>  net/xfrm/xfrm_state.c                   | 20 ++++---
> > >>  security/integrity/ima/ima_api.c        |  7 ++-
> > >>  security/integrity/integrity_audit.c    |  6 +-
> > >>  security/security.c                     | 46 +++++++++-----
> > >>  security/smack/smackfs.c                |  3 +-
> > >>  25 files changed, 274 insertions(+), 107 deletions(-)
> > > ...
> > >
> > >> diff --git a/include/linux/audit.h b/include/linux/audit.h
> > >> index 97cd7471e572..229cd71fbf09 100644
> > >> --- a/include/linux/audit.h
> > >> +++ b/include/linux/audit.h
> > >> @@ -386,6 +395,19 @@ static inline void audit_ptrace(struct task_struct *t)
> > >>                 __audit_ptrace(t);
> > >>  }
> > >>
> > >> +static inline struct audit_context *audit_alloc_for_lsm(gfp_t gfp)
> > >> +{
> > >> +       struct audit_context *context = audit_context();
> > >> +
> > >> +       if (context)
> > >> +               return context;
> > >> +
> > >> +       if (lsm_multiple_contexts())
> > >> +               return audit_alloc_local(gfp);
> > >> +
> > >> +       return NULL;
> > >> +}
> > > See my other comments, but this seems wrong at face value.  The
> > > additional LSM record should happen as part of the existing audit log
> > > functions.
> >
> > I'm good with that. But if you defer calling audit_alloc_local()
> > until you know you need it you may be in a place where you can't
> > associate the new context with the event. I think. I will have
> > another go at it.
> 
> I can't think of a case where you would ever not know if you need to
> allocate a local context at the start.  If you are unsure, get in
> touch and we can work it out.
> 
> > > I think I was distracted with the local context issue and I've lost
> > > track of the details here, perhaps it's best to fix the local context
> > > issue first (that should be a big change to this patch) and then we
> > > can take another look.
> >
> > I really need to move forward. I'll give allocation of local contexts
> > as necessary in audit_log_task_context() another shot.
> 
> I appreciate the desire to move forward, and while I can't speak for
> everyone, I'll do my best to work with you to find a good solution.
> If you get stuck or aren't sure you know how to reach me :)
> 
> As a start, I might suggest looking at some of the recent audit
> container ID patchsets from Richard; while they have had some issues,
> they should serve as a basic example of what we mean when we talk
> about "local contexts" and how they should be used.
> 
> -- 
> paul moore
> www.paul-moore.com
> 
> --
> Linux-audit mailing list
> Linux-audit@redhat.com
> https://listman.redhat.com/mailman/listinfo/linux-audit

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635

Re: [PATCH v26 22/25] Audit: Add new record for multiple process LSM attributes

[Casey Schaufler]

On 5/21/2021 1:19 PM, Paul Moore wrote:
> On Thu, May 13, 2021 at 4:32 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
>> Create a new audit record type to contain the subject information
>> when there are multiple security modules that require such data.
>> This record is linked with the same timestamp and serial number
>> using the audit_alloc_local() mechanism.
> The record is linked with the other associated records into a single
> event, it doesn't matter if it gets the timestamp/serial from
> audit_alloc_local() or an existing audit event, e.g. ongoing syscall.
>
>> The record is produced only in cases where there is more than one
>> security module with a process "context".
>> In cases where this record is produced the subj= fields of
>> other records in the audit event will be set to "subj=?".
>>
>> An example of the MAC_TASK_CONTEXTS (1420) record is:
>>
>>         type=UNKNOWN[1420]
>>         msg=audit(1600880931.832:113)
>>         subj_apparmor==unconfined
> It should be just a single "=" in the line above.
>
>>         subj_smack=_
>>
>> There will be a subj_$LSM= entry for each security module
>> LSM that supports the secid_to_secctx and secctx_to_secid
>> hooks. The BPF security module implements secid/secctx
>> translation hooks, so it has to be considered to provide a
>> secctx even though it may not actually do so.
>>
>> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
>> To: paul@paul-moore.com
>> To: linux-audit@redhat.com
>> To: rgb@redhat.com
>> Cc: netdev@vger.kernel.org
>> ---
>>  drivers/android/binder.c                |  2 +-
>>  include/linux/audit.h                   | 24 ++++++++
>>  include/linux/security.h                | 16 ++++-
>>  include/net/netlabel.h                  |  3 +-
>>  include/net/scm.h                       |  2 +-
>>  include/net/xfrm.h                      | 13 +++-
>>  include/uapi/linux/audit.h              |  1 +
>>  kernel/audit.c                          | 80 ++++++++++++++++++-------
>>  kernel/audit.h                          |  3 +
>>  kernel/auditfilter.c                    |  6 +-
>>  kernel/auditsc.c                        | 75 ++++++++++++++++++++---
>>  net/ipv4/ip_sockglue.c                  |  2 +-
>>  net/netfilter/nf_conntrack_netlink.c    |  4 +-
>>  net/netfilter/nf_conntrack_standalone.c |  2 +-
>>  net/netfilter/nfnetlink_queue.c         |  2 +-
>>  net/netlabel/netlabel_domainhash.c      |  4 +-
>>  net/netlabel/netlabel_unlabeled.c       | 24 ++++----
>>  net/netlabel/netlabel_user.c            | 20 ++++---
>>  net/netlabel/netlabel_user.h            |  6 +-
>>  net/xfrm/xfrm_policy.c                  | 10 ++--
>>  net/xfrm/xfrm_state.c                   | 20 ++++---
>>  security/integrity/ima/ima_api.c        |  7 ++-
>>  security/integrity/integrity_audit.c    |  6 +-
>>  security/security.c                     | 46 +++++++++-----
>>  security/smack/smackfs.c                |  3 +-
>>  25 files changed, 274 insertions(+), 107 deletions(-)
> ...
>
>> diff --git a/include/linux/audit.h b/include/linux/audit.h
>> index 97cd7471e572..229cd71fbf09 100644
>> --- a/include/linux/audit.h
>> +++ b/include/linux/audit.h
>> @@ -386,6 +395,19 @@ static inline void audit_ptrace(struct task_struct *t)
>>                 __audit_ptrace(t);
>>  }
>>
>> +static inline struct audit_context *audit_alloc_for_lsm(gfp_t gfp)
>> +{
>> +       struct audit_context *context = audit_context();
>> +
>> +       if (context)
>> +               return context;
>> +
>> +       if (lsm_multiple_contexts())
>> +               return audit_alloc_local(gfp);
>> +
>> +       return NULL;
>> +}
> See my other comments, but this seems wrong at face value.  The
> additional LSM record should happen as part of the existing audit log
> functions.
>
>> diff --git a/include/linux/security.h b/include/linux/security.h
>> index 0129400ff6e9..ddab456e93d3 100644
>> --- a/include/linux/security.h
>> +++ b/include/linux/security.h
>> @@ -182,6 +182,8 @@ struct lsmblob {
>>  #define LSMBLOB_INVALID                -1      /* Not a valid LSM slot number */
>>  #define LSMBLOB_NEEDED         -2      /* Slot requested on initialization */
>>  #define LSMBLOB_NOT_NEEDED     -3      /* Slot not requested */
>> +#define LSMBLOB_DISPLAY                -4      /* Use the "display" slot */
>> +#define LSMBLOB_FIRST          -5      /* Use the default "display" slot */
>>
>>  /**
>>   * lsmblob_init - initialize an lsmblob structure
>> @@ -248,6 +250,15 @@ static inline u32 lsmblob_value(const struct lsmblob *blob)
>>         return 0;
>>  }
>>
>> +static inline bool lsm_multiple_contexts(void)
>> +{
>> +#ifdef CONFIG_SECURITY
>> +       return lsm_slot_to_name(1) != NULL;
>> +#else
>> +       return false;
>> +#endif
>> +}
>> +
>>  /* These functions are in security/commoncap.c */
>>  extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
>>                        int cap, unsigned int opts);
>> @@ -578,7 +589,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
>>                          size_t size);
>>  int security_netlink_send(struct sock *sk, struct sk_buff *skb);
>>  int security_ismaclabel(const char *name);
>> -int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp);
>> +int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp,
>> +                            int display);
>>  int security_secctx_to_secid(const char *secdata, u32 seclen,
>>                              struct lsmblob *blob);
>>  void security_release_secctx(struct lsmcontext *cp);
>> @@ -1433,7 +1445,7 @@ static inline int security_ismaclabel(const char *name)
>>  }
>>
>>  static inline int security_secid_to_secctx(struct lsmblob *blob,
>> -                                          struct lsmcontext *cp)
>> +                                          struct lsmcontext *cp, int display)
>>  {
>>         return -EOPNOTSUPP;
>>  }
>> diff --git a/include/net/netlabel.h b/include/net/netlabel.h
>> index 73fc25b4042b..9bc1f969a25d 100644
>> --- a/include/net/netlabel.h
>> +++ b/include/net/netlabel.h
>> @@ -97,7 +97,8 @@ struct calipso_doi;
>>
>>  /* NetLabel audit information */
>>  struct netlbl_audit {
>> -       u32 secid;
>> +       struct audit_context *localcontext;
>> +       struct lsmblob lsmdata;
>>         kuid_t loginuid;
>>         unsigned int sessionid;
>>  };
>> diff --git a/include/net/scm.h b/include/net/scm.h
>> index b77a52f93389..f4d567d4885e 100644
>> --- a/include/net/scm.h
>> +++ b/include/net/scm.h
>> @@ -101,7 +101,7 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
>>                  * and the infrastructure will know which it is.
>>                  */
>>                 lsmblob_init(&lb, scm->secid);
>> -               err = security_secid_to_secctx(&lb, &context);
>> +               err = security_secid_to_secctx(&lb, &context, LSMBLOB_DISPLAY);
>>
>>                 if (!err) {
>>                         put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, context.len,
>> diff --git a/include/net/xfrm.h b/include/net/xfrm.h
>> index c58a6d4eb610..f8ad20d34498 100644
>> --- a/include/net/xfrm.h
>> +++ b/include/net/xfrm.h
>> @@ -669,13 +669,22 @@ struct xfrm_spi_skb_cb {
>>  #define XFRM_SPI_SKB_CB(__skb) ((struct xfrm_spi_skb_cb *)&((__skb)->cb[0]))
>>
>>  #ifdef CONFIG_AUDITSYSCALL
>> -static inline struct audit_buffer *xfrm_audit_start(const char *op)
>> +static inline struct audit_buffer *xfrm_audit_start(const char *op,
>> +                                                   struct audit_context **lac)
>>  {
>> +       struct audit_context *context;
>>         struct audit_buffer *audit_buf = NULL;
>>
>>         if (audit_enabled == AUDIT_OFF)
>>                 return NULL;
>> -       audit_buf = audit_log_start(audit_context(), GFP_ATOMIC,
>> +       context = audit_context();
>> +       if (lac != NULL) {
>> +               if (lsm_multiple_contexts() && context == NULL)
>> +                       context = audit_alloc_local(GFP_ATOMIC);
>> +               *lac = context;
>> +       }
> Okay, we've got a disconnect here regarding "audit contexts" and
> "local contexts", skip down below where I attempt to explain things a
> little more but basically if there is a place that uses this pattern:
>
>   audit_log_start(audit_context(), ...);
>
> ... you don't need, or want, a "local context".  You might need a
> local context if you see the following pattern:
>
>   audit_log_start(NULL, ...);
>
> The "local context" idea is a hack and should be avoided whenever
> possible; if you have an existing audit context from a syscall, or
> something else, you *really* should use it ... or have a *really* good
> explanation as to why you can not.
>
>> +       audit_buf = audit_log_start(context, GFP_ATOMIC,
>>                                     AUDIT_MAC_IPSEC_EVENT);
>>         if (audit_buf == NULL)
>>                 return NULL;
>> diff --git a/kernel/audit.c b/kernel/audit.c
>> index 841123390d41..60c027d7759c 100644
>> --- a/kernel/audit.c
>> +++ b/kernel/audit.c
>> @@ -386,10 +386,12 @@ void audit_log_lost(const char *message)
>>  static int audit_log_config_change(char *function_name, u32 new, u32 old,
>>                                    int allow_changes)
>>  {
>> +       struct audit_context *context;
>>         struct audit_buffer *ab;
>>         int rc = 0;
>>
>> -       ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
>> +       context = audit_alloc_for_lsm(GFP_KERNEL);
>> +       ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
> Use the existing context, don't create your own, it breaks the record
> associations in the audit event stream.
>
>>         if (unlikely(!ab))
>>                 return rc;
>>         audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
>> @@ -398,7 +400,7 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old,
>>         if (rc)
>>                 allow_changes = 0; /* Something weird, deny request */
>>         audit_log_format(ab, " res=%d", allow_changes);
>> -       audit_log_end(ab);
>> +       audit_log_end_local(ab, context);
> More on this below, but we really should just use audit_log_end(),
> "local contexts" are not special, the are regular audit contexts ...
> although if they are used properly (limited scope) you do need to free
> them when you are done.
>
>>         return rc;
>>  }
>>
>> @@ -1357,7 +1355,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
>>                                 if (err)
>>                                         break;
>>                         }
>> -                       audit_log_user_recv_msg(&ab, msg_type);
>> +                       lcontext = audit_alloc_for_lsm(GFP_KERNEL);
>> +                       audit_log_common_recv_msg(lcontext, &ab, msg_type);
> Same.
>
>>                         if (msg_type != AUDIT_USER_TTY) {
>>                                 /* ensure NULL termination */
>>                                 str[data_len - 1] = '\0';
>> @@ -1370,7 +1369,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
>>                                         data_len--;
>>                                 audit_log_n_untrustedstring(ab, str, data_len);
>>                         }
>> -                       audit_log_end(ab);
>> +                       audit_log_end_local(ab, lcontext);
> Same.
>
>>                 }
>>                 break;
>>         case AUDIT_ADD_RULE:
>> @@ -1378,13 +1377,14 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
>>                 if (data_len < sizeof(struct audit_rule_data))
>>                         return -EINVAL;
>>                 if (audit_enabled == AUDIT_LOCKED) {
>> -                       audit_log_common_recv_msg(audit_context(), &ab,
>> +                       lcontext = audit_alloc_for_lsm(GFP_KERNEL);
>> +                       audit_log_common_recv_msg(lcontext, &ab,
>>                                                   AUDIT_CONFIG_CHANGE);
>>                         audit_log_format(ab, " op=%s audit_enabled=%d res=0",
>>                                          msg_type == AUDIT_ADD_RULE ?
>>                                                 "add_rule" : "remove_rule",
>>                                          audit_enabled);
>> -                       audit_log_end(ab);
>> +                       audit_log_end_local(ab, lcontext);
> Same.  I'm going to stop calling these out, I think you get the idea.
>
>> @@ -2396,6 +2415,21 @@ void audit_log_end(struct audit_buffer *ab)
>>         audit_buffer_free(ab);
>>  }
>>
>> +/**
>> + * audit_log_end_local - end one audit record with local context
>> + * @ab: the audit_buffer
>> + * @context: the local context
>> + *
>> + * Emit an LSM context record if appropriate, then end the audit event
>> + * in the usual way.
>> + */
>> +void audit_log_end_local(struct audit_buffer *ab, struct audit_context *context)
>> +{
>> +       audit_log_end(ab);
>> +       audit_log_lsm_common(context);
>> +       audit_free_local(context);
>> +}
> Eeesh, no, not this please.
>
> First, some background on audit contexts and the idea of a "local
> context" as we have been using it in the audit container ID work,
> which is where this originated.  An audit context contains a few
> things, but likely the most important for this discussion is the audit
> event timestamp and serial number (I may refer to this combo as just a
> "timestamp" in the future); this timestamp/serial is shared across all
> of the audit records that make up this audit event, linking them
> together.  A shared timestamp is what allows you to group an open()
> SYSCALL record with the PATH record that provides the file's pathname
> info.
>
> While there are some exceptions in the current code, most audit events
> occur as a result of a syscall, and their audit context in this case
> is the syscall's audit context (see the open() example above), but
> there are some cases being discussed where we have an audit event that
> does not occur as a result of a syscall but there is a need to group
> multiple audit records together in a single event.  This is where the
> "local context" comes into play, it allows us to create an audit
> context outside of a syscall and share that context across multiple
> audit records, allowing the records to share a timestamp/serial and
> grouping them together as a single audit event in the audit stream.
>
> While a function like audit_alloc_local() make sense, there really
> shouldn't be an audit_log_end_local() function, the normal
> audit_log_end() function should be used.
>
> Does that make sense?
>
>> diff --git a/kernel/audit.h b/kernel/audit.h
>> index 27ef690afd30..5ad0c6819aa8 100644
>> --- a/kernel/audit.h
>> +++ b/kernel/audit.h
>> @@ -100,6 +100,7 @@ struct audit_context {
>>         int                 dummy;      /* must be the first element */
>>         int                 in_syscall; /* 1 if task is in a syscall */
>>         bool                local;      /* local context needed */
>> +       bool                lsmdone;    /* multiple security reported */
> "lsmdone" doesn't seem consistent with the comment, how about
> "lsm_multi" or something similar?
>
>>         enum audit_state    state, current_state;
>>         unsigned int        serial;     /* serial number for record */
>>         int                 major;      /* syscall number */
>> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
>> index d4e061f95da8..55509faf5341 100644
>> --- a/kernel/auditsc.c
>> +++ b/kernel/auditsc.c
>> @@ -1013,6 +1013,13 @@ void audit_free_context(struct audit_context *context)
>>  }
>>  EXPORT_SYMBOL(audit_free_context);
>>
>> +void audit_free_local(struct audit_context *context)
>> +{
>> +       if (context && context->local)
>> +               audit_free_context(context);
>> +}
>> +EXPORT_SYMBOL(audit_free_local);
> We don't need this function, just use audit_free_context().  A "local
> context" is the same as a non-local context; what makes a context
> "local" is the scope of the audit context (local function scope vs
> syscall scope) and nothing else.
>
>> @@ -1504,6 +1512,47 @@ static void audit_log_proctitle(void)
>>         audit_log_end(ab);
>>  }
>>
>> +void audit_log_lsm_common(struct audit_context *context)
>> +{
>> +       struct audit_buffer *ab;
>> +       struct lsmcontext lsmdata;
>> +       bool sep = false;
>> +       int error;
>> +       int i;
>> +
>> +       if (!lsm_multiple_contexts() || context == NULL ||
>> +           !lsmblob_is_set(&context->lsm))
>> +               return;
>> +
>> +       ab = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_TASK_CONTEXTS);
>> +       if (!ab)
>> +               return; /* audit_panic or being filtered */
> We should be consistent with our use of audit_panic() when we bail on
> error; we use it below, but not here - why?
>
>> +       for (i = 0; i < LSMBLOB_ENTRIES; i++) {
>> +               if (context->lsm.secid[i] == 0)
>> +                       continue;
>> +               error = security_secid_to_secctx(&context->lsm, &lsmdata, i);
>> +               if (error && error != -EINVAL) {
>> +                       audit_panic("error in audit_log_lsm");
>> +                       return;
>> +               }
>> +
>> +               audit_log_format(ab, "%ssubj_%s=%s", sep ? " " : "",
>> +                                lsm_slot_to_name(i), lsmdata.context);
>> +               sep = true;
>> +               security_release_secctx(&lsmdata);
>> +       }
>> +       audit_log_end(ab);
>> +       context->lsmdone = true;
> Maybe I missed it, but why do we need this flag?
>
>> +}
>> +
>> +void audit_log_lsm(struct audit_context *context)
>> +{
>> +       if (!context->lsmdone)
>> +               audit_log_lsm_common(context);
>> +}
> I think I was distracted with the local context issue and I've lost
> track of the details here, perhaps it's best to fix the local context
> issue first (that should be a big change to this patch) and then we
> can take another look.
>
>
> --
> paul moore
> www.paul-moore.com

[PATCH v26 23/25] Audit: Add a new record for multiple object LSM attributes

[Casey Schaufler]

Create a new audit record type to contain the object information
when there are multiple security modules that may require such data.
This record is linked with the same timestamp and serial number.

An example of the MAC_OBJ_CONTEXTS (1421) record is:

        type=UNKNOWN[1421]
        msg=audit(1601152467.009:1050):
        obj_selinux=unconfined_u:object_r:user_home_t:s0

Not all security modules that can provide object information
do so in all cases. It is possible that a security module won't
apply an object attribute in all cases.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-audit@redhat.com
To: Paul Moore <paul@paul-moore.com>
---
 include/linux/audit.h      |  7 ++++
 include/uapi/linux/audit.h |  1 +
 kernel/audit.c             | 53 +++++++++++++++++++++++++++
 kernel/audit.h             |  4 +--
 kernel/auditsc.c           | 73 +++++++-------------------------------
 5 files changed, 75 insertions(+), 63 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 229cd71fbf09..b92ad58bc97d 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -189,6 +189,8 @@ extern void		    audit_log_path_denied(int type,
 extern void		    audit_log_lost(const char *message);
 
 extern int audit_log_task_context(struct audit_buffer *ab);
+extern int audit_log_object_context(struct audit_buffer *ab,
+				    struct lsmblob *blob);
 extern void audit_log_task_info(struct audit_buffer *ab);
 extern void audit_log_lsm(struct audit_context *context);
 
@@ -256,6 +258,11 @@ static inline int audit_log_task_context(struct audit_buffer *ab)
 {
 	return 0;
 }
+static inline int audit_log_object_context(struct audit_buffer *ab,
+					   struct lsmblob *blob)
+{
+	return 0;
+}
 static inline void audit_log_task_info(struct audit_buffer *ab)
 { }
 static void audit_log_lsm(struct audit_context *context)
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 2a63720e56f6..dbb1dce16962 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -140,6 +140,7 @@
 #define AUDIT_MAC_CALIPSO_ADD	1418	/* NetLabel: add CALIPSO DOI entry */
 #define AUDIT_MAC_CALIPSO_DEL	1419	/* NetLabel: del CALIPSO DOI entry */
 #define AUDIT_MAC_TASK_CONTEXTS	1420	/* Multiple LSM contexts */
+#define AUDIT_MAC_OBJ_CONTEXTS	1421	/* Multiple LSM object contexts */
 
 #define AUDIT_FIRST_KERN_ANOM_MSG   1700
 #define AUDIT_LAST_KERN_ANOM_MSG    1799
diff --git a/kernel/audit.c b/kernel/audit.c
index 60c027d7759c..5bef8227c526 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -2171,6 +2171,59 @@ int audit_log_task_context(struct audit_buffer *ab)
 }
 EXPORT_SYMBOL(audit_log_task_context);
 
+int audit_log_object_context(struct audit_buffer *ab,
+				    struct lsmblob *blob)
+{
+	int i;
+	int error;
+	bool sep = false;
+	struct lsmcontext lsmdata;
+	struct audit_buffer *lsmab = NULL;
+	struct audit_context *context = NULL;
+
+	/*
+	 * If there is more than one security module that has a
+	 * object "context" it's necessary to put the object data
+	 * into a separate record to maintain compatibility.
+	 */
+	if (lsm_multiple_contexts()) {
+		audit_log_format(ab, " obj=?");
+		context = ab->ctx;
+		if (context)
+			lsmab = audit_log_start(context, GFP_KERNEL,
+						AUDIT_MAC_OBJ_CONTEXTS);
+	}
+
+	for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+		if (blob->secid[i] == 0)
+			continue;
+		error = security_secid_to_secctx(blob, &lsmdata, i);
+		if (error && error != -EINVAL) {
+			audit_panic("error in audit_log_object_context");
+			return error;
+		}
+
+		if (context) {
+			audit_log_format(lsmab, "%sobj_%s=%s",
+					 sep ? " " : "",
+					 lsm_slot_to_name(i),
+					 lsmdata.context);
+			sep = true;
+		} else
+			audit_log_format(ab, " obj=%s", lsmdata.context);
+
+		security_release_secctx(&lsmdata);
+		if (!context)
+			break;
+	}
+
+	if (context)
+		audit_log_end(lsmab);
+
+	return 0;
+}
+EXPORT_SYMBOL(audit_log_object_context);
+
 void audit_log_d_path_exe(struct audit_buffer *ab,
 			  struct mm_struct *mm)
 {
diff --git a/kernel/audit.h b/kernel/audit.h
index 5ad0c6819aa8..952c7a1f2f3c 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -78,7 +78,7 @@ struct audit_names {
 	kuid_t			uid;
 	kgid_t			gid;
 	dev_t			rdev;
-	u32			osid;
+	struct lsmblob		oblob;
 	struct audit_cap_data	fcap;
 	unsigned int		fcap_ver;
 	unsigned char		type;		/* record type */
@@ -155,7 +155,7 @@ struct audit_context {
 			kuid_t			uid;
 			kgid_t			gid;
 			umode_t			mode;
-			u32			osid;
+			struct lsmblob		oblob;
 			int			has_perm;
 			uid_t			perm_uid;
 			gid_t			perm_gid;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 55509faf5341..71d5da2f0ee3 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -685,14 +685,6 @@ static int audit_filter_rules(struct task_struct *tsk,
 			if (f->lsm_isset) {
 				/* Find files that match */
 				if (name) {
-					/*
-					 * lsmblob_init sets all values in the
-					 * lsmblob to sid. This is temporary
-					 * until name->osid is converted to a
-					 * lsmblob, which happens later in
-					 * this patch set.
-					 */
-					lsmblob_init(&blob, name->osid);
 					result = security_audit_rule_match(
 								&blob,
 								f->type,
@@ -700,7 +692,6 @@ static int audit_filter_rules(struct task_struct *tsk,
 								f->lsm_rules);
 				} else if (ctx) {
 					list_for_each_entry(n, &ctx->names_list, list) {
-						lsmblob_init(&blob, name->osid);
 						if (security_audit_rule_match(
 								&blob,
 								f->type,
@@ -714,8 +705,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 				/* Find ipc objects that match */
 				if (!ctx || ctx->type != AUDIT_IPC)
 					break;
-				lsmblob_init(&blob, ctx->ipc.osid);
-				if (security_audit_rule_match(&blob,
+				if (security_audit_rule_match(&ctx->ipc.oblob,
 							      f->type, f->op,
 							      f->lsm_rules))
 					++result;
@@ -1026,7 +1016,6 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 				 struct lsmblob *blob, char *comm)
 {
 	struct audit_buffer *ab;
-	struct lsmcontext lsmctx;
 	int rc = 0;
 
 	ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
@@ -1036,15 +1025,8 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
 	audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid,
 			 from_kuid(&init_user_ns, auid),
 			 from_kuid(&init_user_ns, uid), sessionid);
-	if (lsmblob_is_set(blob)) {
-		if (security_secid_to_secctx(blob, &lsmctx, LSMBLOB_FIRST)) {
-			audit_log_format(ab, " obj=(none)");
-			rc = 1;
-		} else {
-			audit_log_format(ab, " obj=%s", lsmctx.context);
-			security_release_secctx(&lsmctx);
-		}
-	}
+	if (lsmblob_is_set(blob))
+		rc = audit_log_object_context(ab, blob);
 	audit_log_format(ab, " ocomm=");
 	audit_log_untrustedstring(ab, comm);
 	audit_log_end(ab);
@@ -1271,26 +1253,15 @@ static void show_special(struct audit_context *context, int *call_panic)
 				context->socketcall.args[i]);
 		break; }
 	case AUDIT_IPC: {
-		u32 osid = context->ipc.osid;
+		struct lsmblob *oblob = &context->ipc.oblob;
 
 		audit_log_format(ab, "ouid=%u ogid=%u mode=%#ho",
 				 from_kuid(&init_user_ns, context->ipc.uid),
 				 from_kgid(&init_user_ns, context->ipc.gid),
 				 context->ipc.mode);
-		if (osid) {
-			struct lsmcontext lsmcxt;
-			struct lsmblob blob;
-
-			lsmblob_init(&blob, osid);
-			if (security_secid_to_secctx(&blob, &lsmcxt,
-						     LSMBLOB_FIRST)) {
-				audit_log_format(ab, " osid=%u", osid);
-				*call_panic = 1;
-			} else {
-				audit_log_format(ab, " obj=%s", lsmcxt.context);
-				security_release_secctx(&lsmcxt);
-			}
-		}
+		if (lsmblob_is_set(oblob) &&
+		    audit_log_object_context(ab, oblob))
+			*call_panic = 1;
 		if (context->ipc.has_perm) {
 			audit_log_end(ab);
 			ab = audit_log_start(context, GFP_KERNEL,
@@ -1433,20 +1404,9 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
 				 from_kgid(&init_user_ns, n->gid),
 				 MAJOR(n->rdev),
 				 MINOR(n->rdev));
-	if (n->osid != 0) {
-		struct lsmblob blob;
-		struct lsmcontext lsmctx;
-
-		lsmblob_init(&blob, n->osid);
-		if (security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_FIRST)) {
-			audit_log_format(ab, " osid=%u", n->osid);
-			if (call_panic)
-				*call_panic = 2;
-		} else {
-			audit_log_format(ab, " obj=%s", lsmctx.context);
-			security_release_secctx(&lsmctx);
-		}
-	}
+	if (lsmblob_is_set(&n->oblob) &&
+	    audit_log_object_context(ab, &n->oblob) && call_panic)
+		*call_panic = 2;
 
 	/* log the audit_names record type */
 	switch (n->type) {
@@ -2034,17 +1994,13 @@ static void audit_copy_inode(struct audit_names *name,
 			     const struct dentry *dentry,
 			     struct inode *inode, unsigned int flags)
 {
-	struct lsmblob blob;
-
 	name->ino   = inode->i_ino;
 	name->dev   = inode->i_sb->s_dev;
 	name->mode  = inode->i_mode;
 	name->uid   = inode->i_uid;
 	name->gid   = inode->i_gid;
 	name->rdev  = inode->i_rdev;
-	security_inode_getsecid(inode, &blob);
-	/* scaffolding until osid is updated */
-	name->osid = blob.secid[0];
+	security_inode_getsecid(inode, &name->oblob);
 	if (flags & AUDIT_INODE_NOEVAL) {
 		name->fcap_ver = -1;
 		return;
@@ -2390,17 +2346,12 @@ void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
 void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
 {
 	struct audit_context *context = audit_context();
-	struct lsmblob blob;
 
 	context->ipc.uid = ipcp->uid;
 	context->ipc.gid = ipcp->gid;
 	context->ipc.mode = ipcp->mode;
 	context->ipc.has_perm = 0;
-	security_ipc_getsecid(ipcp, &blob);
-	/* context->ipc.osid will be changed to a lsmblob later in
-	 * the patch series. This will allow auditing of all the object
-	 * labels associated with the ipc object. */
-	context->ipc.osid = lsmblob_value(&blob);
+	security_ipc_getsecid(ipcp, &context->ipc.oblob);
 	context->type = AUDIT_IPC;
 }
 
-- 
2.29.2

[PATCH v26 24/25] LSM: Add /proc attr entry for full LSM context

[Casey Schaufler]

Add an entry /proc/.../attr/context which displays the full
process security "context" in compound format:
        lsm1\0value\0lsm2\0value\0...
This entry is not writable.

A security module may decide that its policy does not allow
this information to be displayed. In this case none of the
information will be displayed.

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-api@vger.kernel.org
Cc: linux-doc@vger.kernel.org
---
 Documentation/ABI/testing/procfs-attr-context | 14 ++++
 Documentation/security/lsm.rst                | 14 ++++
 fs/proc/base.c                                |  1 +
 include/linux/lsm_hooks.h                     |  6 ++
 security/apparmor/include/procattr.h          |  2 +-
 security/apparmor/lsm.c                       |  8 +-
 security/apparmor/procattr.c                  | 22 +++---
 security/security.c                           | 79 +++++++++++++++++++
 security/selinux/hooks.c                      |  2 +-
 security/smack/smack_lsm.c                    |  2 +-
 10 files changed, 135 insertions(+), 15 deletions(-)
 create mode 100644 Documentation/ABI/testing/procfs-attr-context

diff --git a/Documentation/ABI/testing/procfs-attr-context b/Documentation/ABI/testing/procfs-attr-context
new file mode 100644
index 000000000000..40da1c397c30
--- /dev/null
+++ b/Documentation/ABI/testing/procfs-attr-context
@@ -0,0 +1,14 @@
+What:		/proc/*/attr/context
+Contact:	linux-security-module@vger.kernel.org,
+Description:	The current security information used by all Linux
+		security module (LSMs) that are active on the system.
+		The details of permissions required to read from
+		this interface and hence obtain the security state
+		of the task identified is dependent on the LSMs that
+		are active on the system.
+		A process cannot write to this interface.
+		The data provided by this interface will have the form:
+			lsm_name\0lsm_data\0[lsm_name\0lsm_data\0]...
+		where lsm_name is the name of the LSM and the following
+		lsm_data is the process data for that LSM.
+Users:		LSM user-space
diff --git a/Documentation/security/lsm.rst b/Documentation/security/lsm.rst
index b77b4a540391..070225ae6ceb 100644
--- a/Documentation/security/lsm.rst
+++ b/Documentation/security/lsm.rst
@@ -143,3 +143,17 @@ separated list of the active security modules.
 The file ``/proc/pid/attr/interface_lsm`` contains the name of the security
 module for which the ``/proc/pid/attr/current`` interface will
 apply. This interface can be written to.
+
+The infrastructure does provide an interface for the special
+case where multiple security modules provide a process context.
+This is provided in compound context format.
+
+-  `lsm\0value\0lsm\0value\0`
+
+The `lsm` and `value` fields are NUL-terminated bytestrings.
+Each field may contain whitespace or non-printable characters.
+The NUL bytes are included in the size of a compound context.
+The context ``Bell\0Secret\0Biba\0Loose\0`` has a size of 23.
+
+The file ``/proc/pid/attr/context`` provides the security
+context of the identified process.
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 10de522f3112..23ebfc35435c 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2808,6 +2808,7 @@ static const struct pid_entry attr_dir_stuff[] = {
 	ATTR(NULL, "keycreate",		0666),
 	ATTR(NULL, "sockcreate",	0666),
 	ATTR(NULL, "interface_lsm",	0666),
+	ATTR(NULL, "context",		0444),
 #ifdef CONFIG_SECURITY_SMACK
 	DIR("smack",			0555,
 	    proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops),
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index d2c4bc94d47f..f6ffe8b069e2 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1397,6 +1397,12 @@
  *	@pages contains the number of pages.
  *	Return 0 if permission is granted.
  *
+ * @getprocattr:
+ *	Provide the named process attribute for display in special files in
+ *	the /proc/.../attr directory.  Attribute naming and the data displayed
+ *	is at the discretion of the security modules.  The exception is the
+ *	"context" attribute, which will contain the security context of the
+ *	task as a nul terminated text string without trailing whitespace.
  * @ismaclabel:
  *	Check if the extended attribute specified by @name
  *	represents a MAC label. Returns 1 if name is a MAC
diff --git a/security/apparmor/include/procattr.h b/security/apparmor/include/procattr.h
index 31689437e0e1..03dbfdb2f2c0 100644
--- a/security/apparmor/include/procattr.h
+++ b/security/apparmor/include/procattr.h
@@ -11,7 +11,7 @@
 #ifndef __AA_PROCATTR_H
 #define __AA_PROCATTR_H
 
-int aa_getprocattr(struct aa_label *label, char **string);
+int aa_getprocattr(struct aa_label *label, char **string, bool newline);
 int aa_setprocattr_changehat(char *args, size_t size, int flags);
 
 #endif /* __AA_PROCATTR_H */
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 4237536106aa..65a004597e53 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -602,6 +602,7 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
 	const struct cred *cred = get_task_cred(task);
 	struct aa_task_ctx *ctx = task_ctx(current);
 	struct aa_label *label = NULL;
+	bool newline = true;
 
 	if (strcmp(name, "current") == 0)
 		label = aa_get_newest_label(cred_label(cred));
@@ -609,11 +610,14 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
 		label = aa_get_newest_label(ctx->previous);
 	else if (strcmp(name, "exec") == 0 && ctx->onexec)
 		label = aa_get_newest_label(ctx->onexec);
-	else
+	else if (strcmp(name, "context") == 0) {
+		label = aa_get_newest_label(cred_label(cred));
+		newline = false;
+	} else
 		error = -EINVAL;
 
 	if (label)
-		error = aa_getprocattr(label, value);
+		error = aa_getprocattr(label, value, newline);
 
 	aa_put_label(label);
 	put_cred(cred);
diff --git a/security/apparmor/procattr.c b/security/apparmor/procattr.c
index c929bf4a3df1..be3b083d9b74 100644
--- a/security/apparmor/procattr.c
+++ b/security/apparmor/procattr.c
@@ -20,6 +20,7 @@
  * aa_getprocattr - Return the profile information for @profile
  * @profile: the profile to print profile info about  (NOT NULL)
  * @string: Returns - string containing the profile info (NOT NULL)
+ * @newline: Should a newline be added to @string.
  *
  * Returns: length of @string on success else error on failure
  *
@@ -30,20 +31,21 @@
  *
  * Returns: size of string placed in @string else error code on failure
  */
-int aa_getprocattr(struct aa_label *label, char **string)
+int aa_getprocattr(struct aa_label *label, char **string, bool newline)
 {
 	struct aa_ns *ns = labels_ns(label);
 	struct aa_ns *current_ns = aa_get_current_ns();
+	int flags = FLAG_VIEW_SUBNS | FLAG_HIDDEN_UNCONFINED;
 	int len;
 
 	if (!aa_ns_visible(current_ns, ns, true)) {
 		aa_put_ns(current_ns);
 		return -EACCES;
 	}
+	if (newline)
+		flags |= FLAG_SHOW_MODE;
 
-	len = aa_label_snxprint(NULL, 0, current_ns, label,
-				FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
-				FLAG_HIDDEN_UNCONFINED);
+	len = aa_label_snxprint(NULL, 0, current_ns, label, flags);
 	AA_BUG(len < 0);
 
 	*string = kmalloc(len + 2, GFP_KERNEL);
@@ -52,19 +54,19 @@ int aa_getprocattr(struct aa_label *label, char **string)
 		return -ENOMEM;
 	}
 
-	len = aa_label_snxprint(*string, len + 2, current_ns, label,
-				FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
-				FLAG_HIDDEN_UNCONFINED);
+	len = aa_label_snxprint(*string, len + 2, current_ns, label, flags);
 	if (len < 0) {
 		aa_put_ns(current_ns);
 		return len;
 	}
 
-	(*string)[len] = '\n';
-	(*string)[len + 1] = 0;
+	if (newline) {
+		(*string)[len] = '\n';
+		(*string)[++len] = 0;
+	}
 
 	aa_put_ns(current_ns);
-	return len + 1;
+	return len;
 }
 
 /**
diff --git a/security/security.c b/security/security.c
index bb4c7f6c62ec..d3ff61442877 100644
--- a/security/security.c
+++ b/security/security.c
@@ -799,6 +799,57 @@ static int lsm_superblock_alloc(struct super_block *sb)
 	return 0;
 }
 
+/**
+ * append_ctx - append a lsm/context pair to a compound context
+ * @ctx: the existing compound context
+ * @ctxlen: size of the old context, including terminating nul byte
+ * @lsm: new lsm name, nul terminated
+ * @new: new context, possibly nul terminated
+ * @newlen: maximum size of @new
+ *
+ * replace @ctx with a new compound context, appending @newlsm and @new
+ * to @ctx. On exit the new data replaces the old, which is freed.
+ * @ctxlen is set to the new size, which includes a trailing nul byte.
+ *
+ * Returns 0 on success, -ENOMEM if no memory is available.
+ */
+static int append_ctx(char **ctx, int *ctxlen, const char *lsm, char *new,
+		      int newlen)
+{
+	char *final;
+	size_t llen;
+	size_t nlen;
+	size_t flen;
+
+	llen = strlen(lsm) + 1;
+	/*
+	 * A security module may or may not provide a trailing nul on
+	 * when returning a security context. There is no definition
+	 * of which it should be, and there are modules that do it
+	 * each way.
+	 */
+	nlen = strnlen(new, newlen);
+
+	flen = *ctxlen + llen + nlen + 1;
+	final = kzalloc(flen, GFP_KERNEL);
+
+	if (final == NULL)
+		return -ENOMEM;
+
+	if (*ctxlen)
+		memcpy(final, *ctx, *ctxlen);
+
+	memcpy(final + *ctxlen, lsm, llen);
+	memcpy(final + *ctxlen + llen, new, nlen);
+
+	kfree(*ctx);
+
+	*ctx = final;
+	*ctxlen = flen;
+
+	return 0;
+}
+
 /*
  * The default value of the LSM hook is defined in linux/lsm_hook_defs.h and
  * can be accessed with:
@@ -2232,6 +2283,10 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
 				char **value)
 {
 	struct security_hook_list *hp;
+	char *final = NULL;
+	char *cp;
+	int rc = 0;
+	int finallen = 0;
 	int ilsm = lsm_task_ilsm(current);
 	int slot = 0;
 
@@ -2259,6 +2314,30 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
 		return -ENOMEM;
 	}
 
+	if (!strcmp(name, "context")) {
+		hlist_for_each_entry(hp, &security_hook_heads.getprocattr,
+				     list) {
+			rc = hp->hook.getprocattr(p, "context", &cp);
+			if (rc == -EINVAL)
+				continue;
+			if (rc < 0) {
+				kfree(final);
+				return rc;
+			}
+			rc = append_ctx(&final, &finallen, hp->lsmid->lsm,
+					cp, rc);
+			kfree(cp);
+			if (rc < 0) {
+				kfree(final);
+				return rc;
+			}
+		}
+		if (final == NULL)
+			return -EINVAL;
+		*value = final;
+		return finallen;
+	}
+
 	hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
 		if (lsm != NULL && strcmp(lsm, hp->lsmid->lsm))
 			continue;
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index b7800fa55a34..0a9af748f77c 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6468,7 +6468,7 @@ static int selinux_getprocattr(struct task_struct *p,
 			goto bad;
 	}
 
-	if (!strcmp(name, "current"))
+	if (!strcmp(name, "current") || !strcmp(name, "context"))
 		sid = __tsec->sid;
 	else if (!strcmp(name, "prev"))
 		sid = __tsec->osid;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index e65497a5c095..1618d7d6154b 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3477,7 +3477,7 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value)
 	char *cp;
 	int slen;
 
-	if (strcmp(name, "current") != 0)
+	if (strcmp(name, "current") != 0 && strcmp(name, "context") != 0)
 		return -EINVAL;
 
 	cp = kstrdup(skp->smk_known, GFP_KERNEL);
-- 
2.29.2

[PATCH v26 25/25] AppArmor: Remove the exclusive flag

[Casey Schaufler]

With the inclusion of the interface LSM process attribute
mechanism AppArmor no longer needs to be treated as an
"exclusive" security module. Remove the flag that indicates
it is exclusive. Remove the stub getpeersec_dgram AppArmor
hook as it has no effect in the single LSM case and
interferes in the multiple LSM case.

Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 security/apparmor/lsm.c | 20 +-------------------
 1 file changed, 1 insertion(+), 19 deletions(-)

diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 65a004597e53..15af5a5cb0c0 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -1138,22 +1138,6 @@ static int apparmor_socket_getpeersec_stream(struct socket *sock,
 	return error;
 }
 
-/**
- * apparmor_socket_getpeersec_dgram - get security label of packet
- * @sock: the peer socket
- * @skb: packet data
- * @secid: pointer to where to put the secid of the packet
- *
- * Sets the netlabel socket state on sk from parent
- */
-static int apparmor_socket_getpeersec_dgram(struct socket *sock,
-					    struct sk_buff *skb, u32 *secid)
-
-{
-	/* TODO: requires secid support */
-	return -ENOPROTOOPT;
-}
-
 /**
  * apparmor_sock_graft - Initialize newly created socket
  * @sk: child sock
@@ -1257,8 +1241,6 @@ static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
 #endif
 	LSM_HOOK_INIT(socket_getpeersec_stream,
 		      apparmor_socket_getpeersec_stream),
-	LSM_HOOK_INIT(socket_getpeersec_dgram,
-		      apparmor_socket_getpeersec_dgram),
 	LSM_HOOK_INIT(sock_graft, apparmor_sock_graft),
 #ifdef CONFIG_NETWORK_SECMARK
 	LSM_HOOK_INIT(inet_conn_request, apparmor_inet_conn_request),
@@ -1928,7 +1910,7 @@ static int __init apparmor_init(void)
 
 DEFINE_LSM(apparmor) = {
 	.name = "apparmor",
-	.flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
+	.flags = LSM_FLAG_LEGACY_MAJOR,
 	.enabled = &apparmor_enabled,
 	.blobs = &apparmor_blob_sizes,
 	.init = apparmor_init,
-- 
2.29.2