[PATCH 1/1] msxml3: Fix use-after-free of dom attributes.

[Yuxuan Shui]

From: Yuxuan Shui

In domelem_removeAttributeNode, we call xmlRemoveProp if attributeNode is NULL. Doing this frees the
xmlNodePtr, leaving a dangling pointer. Which later in domattr_Release causes a use-after-free.

Found by ASan.
---
 dlls/msxml3/element.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/dlls/msxml3/element.c b/dlls/msxml3/element.c
index fd9a2973cd8..0859576ded2 100644
--- a/dlls/msxml3/element.c
+++ b/dlls/msxml3/element.c
@@ -1501,17 +1501,9 @@ static HRESULT WINAPI domelem_removeAttributeNode(
     if (This->node.node != attr_node->node->parent)
         return E_INVALIDARG;

-    if (attributeNode)
-    {
-        xmlUnlinkNode(attr_node->node );
-        xmldoc_add_orphan(attr_node->node->doc, attr_node->node);
-        *attributeNode = (IXMLDOMAttribute*)create_node(attr_node->node);
-    }
-    else
-    {
-        if (xmlRemoveProp((xmlAttrPtr)attr_node->node) == -1)
-            return E_INVALIDARG;
-    }
+    xmlUnlinkNode(attr_node->node);
+    xmldoc_add_orphan(attr_node->node->doc, attr_node->node);
+    if (attributeNode) *attributeNode = (IXMLDOMAttribute*)create_node(attr_node->node);
     return S_OK;
 }