Revert "libsepol: Make an unknown permission an error in CIL"

There are still invalid CILs out in the wild on Android.
Do not throw an error in this case, preserve the old behavior.

This reverts commit dc4e541.

libsepol/cil/src/cil_resolve_ast.c

@@ -131,14 +131,18 @@ static int __cil_resolve_perms(symtab_t *class_symtab, symtab_t *common_symtab,
 				}
 			}
 			if (rc != SEPOL_OK) {
+				struct cil_list *empty_list;
 				if (class_flavor == CIL_MAP_CLASS) {
 					cil_log(CIL_ERR, "Failed to resolve permission %s for map class\n", (char*)curr->data);
-				} else {
-					cil_log(CIL_ERR, "Failed to resolve permission %s\n", (char*)curr->data);
+					goto exit;
 				}
-				goto exit;
+				cil_log(CIL_WARN, "Failed to resolve permission %s\n", (char*)curr->data);
+				/* Use an empty list to represent unknown perm */
+				cil_list_init(&empty_list, perm_strs->flavor);
+				cil_list_append(*perm_datums, CIL_LIST, empty_list);
+			} else {
+				cil_list_append(*perm_datums, CIL_DATUM, perm_datum);
 			}
-			cil_list_append(*perm_datums, CIL_DATUM, perm_datum);
 		} else {
 			cil_list_append(*perm_datums, curr->flavor, curr->data);
 		}