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From: Casey Schaufler <casey@schaufler-ca.com>
To: casey.schaufler@intel.com, jmorris@namei.org,
	linux-security-module@vger.kernel.org, selinux@vger.kernel.org
Cc: casey@schaufler-ca.com, keescook@chromium.org,
	john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp,
	paul@paul-moore.com, sds@tycho.nsa.gov
Subject: [PATCH 04/25] LSM: Use lsmblob in security_kernel_act_as
Date: Tue, 12 Nov 2019 16:08:52 -0800	[thread overview]
Message-ID: <20191113000913.5414-5-casey@schaufler-ca.com> (raw)
In-Reply-To: <20191113000913.5414-1-casey@schaufler-ca.com>

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 it's 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.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.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 18639c069263..03ae0182cba6 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
@@ -165,7 +166,7 @@ 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 2df58448f1f2..2b0ab47cfb26 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -435,7 +435,7 @@ 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);
@@ -1041,7 +1041,8 @@ 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 c0a4c12d38b2..846ac4b23c16 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -732,14 +732,14 @@ 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);
 
@@ -755,6 +755,7 @@ EXPORT_SYMBOL(set_security_override);
  */
 int set_security_override_from_ctx(struct cred *new, const char *secctx)
 {
+	struct lsmblob blob;
 	u32 secid;
 	int ret;
 
@@ -762,7 +763,8 @@ 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 7c386cbe4cf3..dd6f212e11af 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1615,9 +1615,19 @@ 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)
-- 
2.20.1


  parent reply	other threads:[~2019-11-13  0:09 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20191113000913.5414-1-casey.ref@schaufler-ca.com>
2019-11-13  0:08 ` [PATCH v10 00/25] LSM: Module stacking for AppArmor Casey Schaufler
2019-11-13  0:08   ` [PATCH 01/25] LSM: Infrastructure management of the sock security Casey Schaufler
2019-11-13  0:08   ` [PATCH 02/25] LSM: Create and manage the lsmblob data structure Casey Schaufler
2019-11-13  0:08   ` [PATCH 03/25] LSM: Use lsmblob in security_audit_rule_match Casey Schaufler
2019-11-13  0:08   ` Casey Schaufler [this message]
2019-11-13  0:08   ` [PATCH 05/25] net: Prepare UDS for security module stacking Casey Schaufler
2019-11-13  0:08   ` [PATCH 06/25] LSM: Use lsmblob in security_secctx_to_secid Casey Schaufler
2019-11-13  0:08   ` [PATCH 07/25] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler
2019-11-13  0:08   ` [PATCH 08/25] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler
2019-11-13  0:08   ` [PATCH 09/25] LSM: Use lsmblob in security_task_getsecid Casey Schaufler
2019-11-13  0:08   ` [PATCH 10/25] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler
2019-11-13  0:08   ` [PATCH 11/25] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler
2019-11-13  0:09   ` [PATCH 12/25] IMA: Change internal interfaces to use lsmblobs Casey Schaufler
2019-11-13  0:09   ` [PATCH 13/25] LSM: Specify which LSM to display Casey Schaufler
2019-11-13  0:09   ` [PATCH 14/25] LSM: Ensure the correct LSM context releaser Casey Schaufler
2019-11-13  0:09   ` [PATCH 15/25] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler
2019-11-13  0:09   ` [PATCH 16/25] LSM: Use lsmcontext in security_dentry_init_security Casey Schaufler

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