[PATCH v32 06/28] LSM: Use lsmblob in security_audit_rule_match

From: Casey Schaufler <casey@schaufler-ca.com>
To: casey.schaufler@intel.com, jmorris@namei.org,
	linux-security-module@vger.kernel.org, selinux@vger.kernel.org
Cc: casey@schaufler-ca.com, linux-audit@redhat.com,
	keescook@chromium.org, john.johansen@canonical.com,
	penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com,
	sds@tycho.nsa.gov, linux-kernel@vger.kernel.org
Subject: [PATCH v32 06/28] LSM: Use lsmblob in security_audit_rule_match
Date: Wed,  2 Feb 2022 15:53:01 -0800	[thread overview]
Message-ID: <20220202235323.23929-7-casey@schaufler-ca.com> (raw)
In-Reply-To: <20220202235323.23929-1-casey@schaufler-ca.com>

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

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

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Cc: linux-audit@redhat.com
---
 include/linux/security.h |  5 +++--
 kernel/auditfilter.c     |  6 ++++--
 kernel/auditsc.c         | 16 +++++++++++-----
 security/security.c      |  5 +++--
 4 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index 1edbb362ee72..3b734ebb7e29 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1946,7 +1946,7 @@ static inline int security_key_getsecurity(struct key *key, char **_buffer)
 int security_audit_rule_init(u32 field, u32 op, char *rulestr,
 			     struct audit_lsm_rules *lsmrules);
 int security_audit_rule_known(struct audit_krule *krule);
-int security_audit_rule_match(u32 secid, u32 field, u32 op,
+int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
 			      struct audit_lsm_rules *lsmrules);
 void security_audit_rule_free(struct audit_lsm_rules *lsmrules);
 
@@ -1963,7 +1963,8 @@ static inline int security_audit_rule_known(struct audit_krule *krule)
 	return 0;
 }
 
-static inline int security_audit_rule_match(u32 secid, u32 field, u32 op,
+static inline int security_audit_rule_match(struct lsmblob *blob,
+					    u32 field, u32 op,
 					    struct audit_lsm_rules *lsmrules)
 {
 	return 0;
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index de75bd6ad866..15cd4fe35e9c 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1337,6 +1337,7 @@ 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];
+			struct lsmblob blob;
 			pid_t pid;
 			u32 sid;
 
@@ -1369,8 +1370,9 @@ int audit_filter(int msgtype, unsigned int listtype)
 			case AUDIT_SUBJ_CLR:
 				if (f->lsm_str) {
 					security_current_getsecid_subj(&sid);
-					result = security_audit_rule_match(sid,
-						   f->type, f->op,
+					lsmblob_init(&blob, sid);
+					result = security_audit_rule_match(
+						   &blob, f->type, f->op,
 						   &f->lsm_rules);
 				}
 				break;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index f1c26a322f9d..e5ca89160b5f 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -468,6 +468,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 	const struct cred *cred;
 	int i, need_sid = 1;
 	u32 sid;
+	struct lsmblob blob;
 	unsigned int sessionid;
 
 	if (ctx && rule->prio <= ctx->prio)
@@ -678,8 +679,10 @@ static int audit_filter_rules(struct task_struct *tsk,
 					security_current_getsecid_subj(&sid);
 					need_sid = 0;
 				}
-				result = security_audit_rule_match(sid, f->type,
-							f->op, &f->lsm_rules);
+				lsmblob_init(&blob, sid);
+				result = security_audit_rule_match(&blob,
+							f->type, f->op,
+							&f->lsm_rules);
 			}
 			break;
 		case AUDIT_OBJ_USER:
@@ -692,15 +695,17 @@ static int audit_filter_rules(struct task_struct *tsk,
 			if (f->lsm_str) {
 				/* Find files that match */
 				if (name) {
+					lsmblob_init(&blob, name->osid);
 					result = security_audit_rule_match(
-								name->osid,
+								&blob,
 								f->type,
 								f->op,
 								&f->lsm_rules);
 				} else if (ctx) {
 					list_for_each_entry(n, &ctx->names_list, list) {
+						lsmblob_init(&blob, n->osid);
 						if (security_audit_rule_match(
-							n->osid, f->type, f->op,
+							&blob, f->type, f->op,
 							&f->lsm_rules)) {
 							++result;
 							break;
@@ -710,7 +715,8 @@ static int audit_filter_rules(struct task_struct *tsk,
 				/* Find ipc objects that match */
 				if (!ctx || ctx->type != AUDIT_IPC)
 					break;
-				if (security_audit_rule_match(ctx->ipc.osid,
+				lsmblob_init(&blob, ctx->ipc.osid);
+				if (security_audit_rule_match(&blob,
 							      f->type, f->op,
 							      &f->lsm_rules))
 					++result;
diff --git a/security/security.c b/security/security.c
index 29fc50322b1f..5b2dc867c57d 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2683,7 +2683,7 @@ void security_audit_rule_free(struct audit_lsm_rules *lsmrules)
 	}
 }
 
-int security_audit_rule_match(u32 secid, u32 field, u32 op,
+int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
 			      struct audit_lsm_rules *lsmrules)
 {
 	struct security_hook_list *hp;
@@ -2694,7 +2694,8 @@ int security_audit_rule_match(u32 secid, u32 field, u32 op,
 			continue;
 		if (lsmrules->rule[hp->lsmid->slot] == NULL)
 			continue;
-		rc = hp->hook.audit_rule_match(secid, field, op,
+		rc = hp->hook.audit_rule_match(blob->secid[hp->lsmid->slot],
+					field, op,
 					&lsmrules->rule[hp->lsmid->slot]);
 		if (rc)
 			return rc;
-- 
2.31.1

