commit 8fbbf5513d609c1770b391b99e33314cd0742704
author Pranjal Jumde <pjumde@apple.com> Tue Mar 08 17:29:00 2016 -0800
committer Daniel Veillard <veillard@redhat.com> Sun May 22 09:33:57 2016 +0800
tree b3e9cb43375453908203e53fb8b758bae78afc04
parent 8f30bdff69edac9075f4663ce3b56b0c52d48ce6

Bug 763071: heap-buffer-overflow in xmlStrncat <https://bugzilla.gnome.org/show_bug.cgi?id=763071>

* xmlstring.c:
(xmlStrncat): Return NULL if xmlStrlen returns a negative length.
(xmlStrncatNew): Ditto.

xmlstring.c

diff --git a/xmlstring.c b/xmlstring.c
index b89c9e9..00287d4 100644
--- a/xmlstring.c
+++ b/xmlstring.c
@@ -457,6 +457,8 @@
         return(xmlStrndup(add, len));
 
     size = xmlStrlen(cur);
+    if (size < 0)
+        return(NULL);
     ret = (xmlChar *) xmlRealloc(cur, (size + len + 1) * sizeof(xmlChar));
     if (ret == NULL) {
         xmlErrMemory(NULL, NULL);
@@ -484,14 +486,19 @@
     int size;
     xmlChar *ret;
 
-    if (len < 0)
+    if (len < 0) {
         len = xmlStrlen(str2);
+        if (len < 0)
+            return(NULL);
+    }
     if ((str2 == NULL) || (len == 0))
         return(xmlStrdup(str1));
     if (str1 == NULL)
         return(xmlStrndup(str2, len));
 
     size = xmlStrlen(str1);
+    if (size < 0)
+        return(NULL);
     ret = (xmlChar *) xmlMalloc((size + len + 1) * sizeof(xmlChar));
     if (ret == NULL) {
         xmlErrMemory(NULL, NULL);