SELinux: return error codes on policy load failure

policy load failure always return EINVAL even if the failure was for some
other reason (usually ENOMEM).  This patch passes error codes back up the
stack where they will make their way to userspace.  This might help in
debugging future problems with policy load.
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

@@ -1760,22 +1760,28 @@ int security_load_policy(void *data, size_t len)
 
 	if (!ss_initialized) {
 		avtab_cache_init();
-		if (policydb_read(&policydb, fp)) {
+		rc = policydb_read(&policydb, fp);
+		if (rc) {
 			avtab_cache_destroy();
-			return -EINVAL;
+			return rc;
 		}
-		if (selinux_set_mapping(&policydb, secclass_map,
-					&current_mapping,
-					&current_mapping_size)) {
+
+		rc = selinux_set_mapping(&policydb, secclass_map,
+					 &current_mapping,
+					 &current_mapping_size);
+		if (rc) {
 			policydb_destroy(&policydb);
 			avtab_cache_destroy();
-			return -EINVAL;
+			return rc;
 		}
-		if (policydb_load_isids(&policydb, &sidtab)) {
+
+		rc = policydb_load_isids(&policydb, &sidtab);
+		if (rc) {
 			policydb_destroy(&policydb);
 			avtab_cache_destroy();
-			return -EINVAL;
+			return rc;
 		}
+
 		security_load_policycaps();
 		ss_initialized = 1;
 		seqno = ++latest_granting;
@@ -1791,8 +1797,9 @@ int security_load_policy(void *data, size_t len)
 	sidtab_hash_eval(&sidtab, "sids");
 #endif
 
-	if (policydb_read(&newpolicydb, fp))
-		return -EINVAL;
+	rc = policydb_read(&newpolicydb, fp);
+	if (rc)
+		return rc;
 
 	/* If switching between different policy types, log MLS status */
 	if (policydb.mls_enabled && !newpolicydb.mls_enabled)
@@ -1807,8 +1814,8 @@ int security_load_policy(void *data, size_t len)
 		return rc;
 	}
 
-	if (selinux_set_mapping(&newpolicydb, secclass_map,
-				&map, &map_size))
+	rc = selinux_set_mapping(&newpolicydb, secclass_map, &map, &map_size);
+	if (rc)
 		goto err;
 
 	rc = security_preserve_bools(&newpolicydb);
@@ -1819,10 +1826,10 @@ int security_load_policy(void *data, size_t len)
 
 	/* Clone the SID table. */
 	sidtab_shutdown(&sidtab);
-	if (sidtab_map(&sidtab, clone_sid, &newsidtab)) {
-		rc = -ENOMEM;
+
+	rc = sidtab_map(&sidtab, clone_sid, &newsidtab);
+	if (rc)
 		goto err;
-	}
 
 	/*
 	 * Convert the internal representations of contexts