From 540a3b58c233db4f2d2becea9c2b79b3ce190055 Mon Sep 17 00:00:00 2001

From: David Drysdale <drysdale@google.com>

Date: Fri, 20 Nov 2015 10:47:12 +0800

Subject: [PATCH] CVE-2015-7497 Avoid an heap buffer overflow in

 xmlDictComputeFastQKey

To: libvir-list@redhat.com

For https://bugzilla.gnome.org/show_bug.cgi?id=756528

It was possible to hit a negative offset in the name indexing

used to randomize the dictionary key generation

Reported and fix provided by David Drysdale @ Google

Signed-off-by: Daniel Veillard <veillard@redhat.com>

---

 dict.c | 5 ++++-

 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/dict.c b/dict.c

index 5f71d55..8c8f931 100644

--- a/dict.c

+++ b/dict.c

@@ -486,7 +486,10 @@ xmlDictComputeFastQKey(const xmlChar *prefix, int plen,

 	value += 30 * (*prefix);

     if (len > 10) {

-        value += name[len - (plen + 1 + 1)];

+        int offset = len - (plen + 1 + 1);

+	if (offset < 0)

+	    offset = len - (10 + 1);

+	value += name[offset];

         len = 10;

 	if (plen > 10)

 	    plen = 10;

-- 

2.5.0