slsm: tree: fix memory leak on success and error path

security/slsm/tree.c

@@ -264,28 +264,34 @@ ssize_t slsm_serialize_subtree(struct slsm_str *buf, struct slsm_str *path_buf,
 
 ssize_t slsm_serialize_tree(char **retbuf) {
 	ssize_t ret;
-	struct slsm_str buf;
-	struct slsm_str path_buf;
+	struct slsm_str buf = {};
+	struct slsm_str path_buf = {};
 
 	if (!rules)
 		return 0;
 
-	ret = slsm_str_init(&buf, 4096);
-	if (ret)
-		return ret;
 	ret = slsm_str_init(&path_buf, 4096);
 	if (ret)
-		return ret;
+		goto out;
+	ret = slsm_str_init(&buf, 4096);
+	if (ret)
+		goto out;
 
 	mutex_lock(&mutex);
 	ret = slsm_serialize_subtree(&buf, &path_buf, rules);
 	mutex_unlock(&mutex);
 
-	if (ret)
-		return ret;
+	if (ret) {
+		kfree(buf.buf);
+		goto out;
+	}
 
 	*retbuf = buf.buf;
-	return (ssize_t)buf.used;
+	ret = (ssize_t)buf.used;
+
+out:
+	kfree(path_buf.buf);
+	return ret;
 }