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

From f5e1174933c65556b5d1c0b3a8f13a27f37a1638 Mon Sep 17 00:00:00 2001
From: Nick Wellnhofer <wellnhofer@aevum.de>
Date: Wed, 15 Feb 2023 13:48:18 +0100
Subject: [PATCH] malloc-fail: Fix memory leak after calling
 xmlXPathWrapNodeSet

Destroy the node set in xmlXPathWrapNodeSet 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/f5e1174933c65556b5d1c0b3a8f13a27f37a1638
Conflict:xpath.c
---
 xpath.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/xpath.c b/xpath.c
index dc99e63..9ead497 100644
--- a/xpath.c
+++ b/xpath.c
@@ -2319,6 +2319,8 @@ xmlXPathContextSetCache(xmlXPathContextPtr ctxt,
  * Wrap the Nodeset @val in a new xmlXPathObjectPtr
  *
  * Returns the created or reused object.
+ *
+ * In case of error the node set is destroyed and NULL is returned.
  */
 static xmlXPathObjectPtr
 xmlXPathCacheWrapNodeSet(xmlXPathContextPtr ctxt, xmlNodeSetPtr val)
@@ -4398,6 +4400,8 @@ xmlXPathNewNodeSetList(xmlNodeSetPtr val)
  * Wrap the Nodeset @val in a new xmlXPathObjectPtr
  *
  * Returns the newly created object.
+ *
+ * In case of error the node set is destroyed and NULL is returned.
  */
 xmlXPathObjectPtr
 xmlXPathWrapNodeSet(xmlNodeSetPtr val) {
@@ -4406,6 +4410,7 @@ xmlXPathWrapNodeSet(xmlNodeSetPtr val) {
     ret = (xmlXPathObjectPtr) xmlMalloc(sizeof(xmlXPathObject));
     if (ret == NULL) {
         xmlXPathErrMemory(NULL, "creating node set object\n");
+        xmlXPathFreeNodeSet(val);
 	return(NULL);
     }
     memset(ret, 0 , (size_t) sizeof(xmlXPathObject));
-- 
2.27.0