xref: /third_party/libxml2/backport-malloc-fail-Fix-memory-leak-in-xmlGetNsList.patch

From a442d16a5fe61626f00f33abe547da9379a37d89 Mon Sep 17 00:00:00 2001
From: Nick Wellnhofer <wellnhofer@aevum.de>
Date: Sun, 26 Feb 2023 14:48:23 +0100
Subject: [PATCH] malloc-fail: Fix memory leak in xmlGetNsList

Found with libFuzzer, see #344.

Reference:https://github.com/GNOME/libxml2/commit/a442d16a5fe61626f00f33abe547da9379a37d89
Conflict:NA
---
 tree.c | 25 +++++++++----------------
 1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/tree.c b/tree.c
index 35bd948..4a80e28 100644
--- a/tree.c
+++ b/tree.c
@@ -5971,7 +5971,7 @@ xmlGetNsList(const xmlDoc *doc ATTRIBUTE_UNUSED, const xmlNode *node)
     xmlNsPtr cur;
     xmlNsPtr *ret = NULL;
     int nbns = 0;
-    int maxns = 10;
+    int maxns = 0;
     int i;
 
     if ((node == NULL) || (node->type == XML_NAMESPACE_DECL))
@@ -5981,16 +5981,6 @@ xmlGetNsList(const xmlDoc *doc ATTRIBUTE_UNUSED, const xmlNode *node)
         if (node->type == XML_ELEMENT_NODE) {
             cur = node->nsDef;
             while (cur != NULL) {
-                if (ret == NULL) {
-                    ret =
-                        (xmlNsPtr *) xmlMalloc((maxns + 1) *
-                                               sizeof(xmlNsPtr));
-                    if (ret == NULL) {
-			xmlTreeErrMemory("getting namespace list");
-                        return (NULL);
-                    }
-                    ret[nbns] = NULL;
-                }
                 for (i = 0; i < nbns; i++) {
                     if ((cur->prefix == ret[i]->prefix) ||
                         (xmlStrEqual(cur->prefix, ret[i]->prefix)))
@@ -5998,15 +5988,18 @@ xmlGetNsList(const xmlDoc *doc ATTRIBUTE_UNUSED, const xmlNode *node)
                 }
                 if (i >= nbns) {
                     if (nbns >= maxns) {
-                        maxns *= 2;
-                        ret = (xmlNsPtr *) xmlRealloc(ret,
-                                                      (maxns +
-                                                       1) *
+                        xmlNsPtr *tmp;
+
+                        maxns = maxns ? maxns * 2 : 10;
+                        tmp = (xmlNsPtr *) xmlRealloc(ret,
+                                                      (maxns + 1) *
                                                       sizeof(xmlNsPtr));
-                        if (ret == NULL) {
+                        if (tmp == NULL) {
 			    xmlTreeErrMemory("getting namespace list");
+                            xmlFree(ret);
                             return (NULL);
                         }
+                        ret = tmp;
                     }
                     ret[nbns++] = cur;
                     ret[nbns] = NULL;
-- 
2.27.0