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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: john.johansen@canonical.com, linux-kernel@vger.kernel.org,
	linux-audit@redhat.com, sds@tycho.nsa.gov
Subject: [PATCH v29 21/28] LSM: Extend security_secid_to_secctx to include module selection
Date: Fri, 24 Sep 2021 10:54:34 -0700	[thread overview]
Message-ID: <20210924175441.7943-22-casey@schaufler-ca.com> (raw)
In-Reply-To: <20210924175441.7943-1-casey@schaufler-ca.com>

Add a parameter to security_secid_to_secctx() to identify
which of the security modules that may be active should
provide the security context. If the parameter is greater
than or equal to zero, the security module associated with
that LSM "slot" is used. If the value is LSMBLOB_DISPLAY
the "interface lsm" is used. If the value is LSMBLOB_FIRST
the first security module providing a hook is used.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 drivers/android/binder.c                |  2 +-
 include/linux/security.h                |  7 +++++--
 include/net/scm.h                       |  2 +-
 kernel/audit.c                          |  4 ++--
 kernel/auditsc.c                        |  7 ++++---
 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_unlabeled.c       | 11 +++++++----
 net/netlabel/netlabel_user.c            |  2 +-
 security/security.c                     | 19 +++++++++++++++++--
 12 files changed, 43 insertions(+), 21 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 1159b4e44b28..e5b1ba72efac 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/security.h b/include/linux/security.h
index e5fd1711bf8b..7096a60fbbfe 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -183,6 +183,8 @@ 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 "interface_lsm" slot */
+#define LSMBLOB_FIRST		-5	/* Use the first slot */
 
 /**
  * lsmblob_init - initialize an lsmblob structure
@@ -579,7 +581,8 @@ 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 ilsm);
 int security_secctx_to_secid(const char *secdata, u32 seclen,
 			     struct lsmblob *blob);
 void security_release_secctx(struct lsmcontext *cp);
@@ -1434,7 +1437,7 @@ 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 ilsm)
 {
 	return -EOPNOTSUPP;
 }
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/kernel/audit.c b/kernel/audit.c
index 841123390d41..3c6e88a9ff62 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1443,7 +1443,7 @@ 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;
 		}
@@ -2138,7 +2138,7 @@ int audit_log_task_context(struct audit_buffer *ab)
 	if (!lsmblob_is_set(&blob))
 		return 0;
 
-	error = security_secid_to_secctx(&blob, &context);
+	error = security_secid_to_secctx(&blob, &context, LSMBLOB_FIRST);
 	if (error) {
 		if (error != -EINVAL)
 			goto error_path;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index d198f307a4d8..e87f21cf9494 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1013,7 +1013,7 @@ 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 {
@@ -1259,7 +1259,8 @@ 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 {
@@ -1416,7 +1417,7 @@ 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;
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 588e4d2dcd15..680bb0969fee 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 0c3e1a8aaf2b..dc31f7a68d6d 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -347,7 +347,7 @@ 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;
 
@@ -658,7 +658,7 @@ 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 c8825e89a21e..541a49d5be9d 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -180,7 +180,7 @@ 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 b6922af82911..0d79832d8130 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_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 60e36324568f..a70269367827 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -437,7 +437,8 @@ 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);
@@ -491,7 +492,8 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
 					  addr->s_addr, mask->s_addr);
 		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);
@@ -550,7 +552,8 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
 					  addr, mask);
 		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);
@@ -1120,7 +1123,7 @@ 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,
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 951ba0639d20..1941877fd16f 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -100,7 +100,7 @@ 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, &context) == 0) {
+	    security_secid_to_secctx(&blob, &context, LSMBLOB_FIRST) == 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 155da0e9b778..96b1d9c37d49 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2355,13 +2355,28 @@ 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;
-- 
2.31.1

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  parent reply	other threads:[~2021-09-24 18:18 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20210924175441.7943-1-casey.ref@schaufler-ca.com>
2021-09-24 17:54 ` [PATCH v29 00/28] LSM: Module stacking for AppArmor Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 01/28] LSM: Infrastructure management of the sock security Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 02/28] LSM: Add the lsmblob data structure Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 03/28] LSM: provide lsm name and id slot mappings Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 04/28] IMA: avoid label collisions with stacked LSMs Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 05/28] LSM: Use lsmblob in security_audit_rule_match Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 06/28] LSM: Use lsmblob in security_kernel_act_as Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 07/28] LSM: Use lsmblob in security_secctx_to_secid Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 08/28] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 09/28] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 10/28] LSM: Use lsmblob in security_task_getsecid Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 11/28] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 12/28] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 13/28] IMA: Change internal interfaces to use lsmblobs Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 14/28] LSM: Specify which LSM to display Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 15/28] LSM: Ensure the correct LSM context releaser Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 16/28] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 17/28] LSM: Use lsmcontext in security_inode_getsecctx Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 18/28] LSM: security_secid_to_secctx in netlink netfilter Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 19/28] NET: Store LSM netlabel data in a lsmblob Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 20/28] LSM: Verify LSM display sanity in binder Casey Schaufler
2021-09-24 17:54   ` Casey Schaufler [this message]
2021-09-24 17:54   ` [PATCH v29 22/28] Audit: Keep multiple LSM data in audit_names Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 23/28] Audit: Create audit_stamp structure Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 24/28] Audit: Add framework for auxiliary records Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 25/28] Audit: Add record for multiple task security contexts Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 26/28] Audit: Add record for multiple object " Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 27/28] LSM: Add /proc attr entry for full LSM context Casey Schaufler
2021-09-24 17:54   ` [PATCH v29 28/28] AppArmor: Remove the exclusive flag Casey Schaufler

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