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

[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 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 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 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 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