SELinux: drop load_mutex in security_load_policy

We used to protect against races of policy load in security_load_policy
by using the load_mutex.  Since then we have added a new mutex,
sel_mutex, in sel_write_load() which is always held across all calls to
security_load_policy we are covered and can safely just drop this one.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>

security/selinux/ss/services.c

@@ -71,7 +71,6 @@ int selinux_policycap_openperm;
 extern const struct selinux_class_perm selinux_class_perm;
 
 static DEFINE_RWLOCK(policy_rwlock);
-static DEFINE_MUTEX(load_mutex);
 
 static struct sidtab sidtab;
 struct policydb policydb;
@@ -1453,17 +1452,13 @@ int security_load_policy(void *data, size_t len)
 	int rc = 0;
 	struct policy_file file = { data, len }, *fp = &file;
 
-	mutex_lock(&load_mutex);
-
 	if (!ss_initialized) {
 		avtab_cache_init();
 		if (policydb_read(&policydb, fp)) {
-			mutex_unlock(&load_mutex);
 			avtab_cache_destroy();
 			return -EINVAL;
 		}
 		if (policydb_load_isids(&policydb, &sidtab)) {
-			mutex_unlock(&load_mutex);
 			policydb_destroy(&policydb);
 			avtab_cache_destroy();
 			return -EINVAL;
@@ -1472,7 +1467,6 @@ int security_load_policy(void *data, size_t len)
 		if (validate_classes(&policydb)) {
 			printk(KERN_ERR
 			       "SELinux:  the definition of a class is incorrect\n");
-			mutex_unlock(&load_mutex);
 			sidtab_destroy(&sidtab);
 			policydb_destroy(&policydb);
 			avtab_cache_destroy();
@@ -1482,7 +1476,6 @@ int security_load_policy(void *data, size_t len)
 		policydb_loaded_version = policydb.policyvers;
 		ss_initialized = 1;
 		seqno = ++latest_granting;
-		mutex_unlock(&load_mutex);
 		selinux_complete_init();
 		avc_ss_reset(seqno);
 		selnl_notify_policyload(seqno);
@@ -1495,13 +1488,10 @@ int security_load_policy(void *data, size_t len)
 	sidtab_hash_eval(&sidtab, "sids");
 #endif
 
-	if (policydb_read(&newpolicydb, fp)) {
-		mutex_unlock(&load_mutex);
+	if (policydb_read(&newpolicydb, fp))
 		return -EINVAL;
-	}
 
 	if (sidtab_init(&newsidtab)) {
-		mutex_unlock(&load_mutex);
 		policydb_destroy(&newpolicydb);
 		return -ENOMEM;
 	}
@@ -1549,7 +1539,6 @@ int security_load_policy(void *data, size_t len)
 	seqno = ++latest_granting;
 	policydb_loaded_version = policydb.policyvers;
 	write_unlock_irq(&policy_rwlock);
-	mutex_unlock(&load_mutex);
 
 	/* Free the old policydb and SID table. */
 	policydb_destroy(&oldpolicydb);
@@ -1563,7 +1552,6 @@ int security_load_policy(void *data, size_t len)
 	return 0;
 
 err:
-	mutex_unlock(&load_mutex);
 	sidtab_destroy(&newsidtab);
 	policydb_destroy(&newpolicydb);
 	return rc;