CVE-2015-7497 Avoid an heap buffer overflow in xmlDictComputeFastQKey
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
diff --git a/dict.c b/dict.c
index 5f71d55..8c8f931 100644
--- a/dict.c
+++ b/dict.c
@@ -486,7 +486,10 @@
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;
