xref: /third_party/libxml2/backport-malloc-fail-Fix-memory-leak-after-calling-xmlXPathWrapString.patch

From d31a0e8e7599bfb691616f7c59ff8d39b982aa55 Mon Sep 17 00:00:00 2001
From: Nick Wellnhofer <wellnhofer@aevum.de>
Date: Wed, 15 Feb 2023 14:47:29 +0100
Subject: [PATCH] malloc-fail: Fix memory leak after calling xmlXPathWrapString

Destroy the string in xmlXPathWrapString if the function fails. This is
somewhat dangerous but matches the expectations of users.

Found with libFuzzer, see #344.

Reference:https://github.com/GNOME/libxml2/commit/d31a0e8e7599bfb691616f7c59ff8d39b982aa55
Conflict:xpath.c
---
 xpath.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/xpath.c b/xpath.c
index 5a6d762..cf74030 100644
--- a/xpath.c
+++ b/xpath.c
@@ -5289,6 +5289,8 @@ xmlXPathNewString(const xmlChar *val) {
  * Wraps the @val string into an XPath object.
  *
  * Returns the newly created object.
+ *
+ * Frees @val in case of error.
  */
 xmlXPathObjectPtr
 xmlXPathWrapString (xmlChar *val) {
@@ -5297,6 +5299,7 @@ xmlXPathWrapString (xmlChar *val) {
     ret = (xmlXPathObjectPtr) xmlMalloc(sizeof(xmlXPathObject));
     if (ret == NULL) {
         xmlXPathErrMemory(NULL, "creating string object\n");
+        xmlFree(val);
 	return(NULL);
     }
     memset(ret, 0 , (size_t) sizeof(xmlXPathObject));
-- 
2.27.0