libxml2: security fix CVE-2015-7497

(From OE-Core rev: 5b72983d1a6d5ad5e9a21d2673d57d1da2333ac6)

Signed-off-by: Armin Kuster <akuster@mvista.com>
Signed-off-by: Joshua Lock <joshua.g.lock@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/libxml/libxml2.inc

@@ -30,6 +30,7 @@ SRC_URI = "ftp://xmlsoft.org/libxml2/libxml2-${PV}.tar.gz;name=libtar \
            file://CVE-2015-7942-2-Fix-an-error-in-previous-Conditional-section-patch.patch \
            file://0001-CVE-2015-8035-Fix-XZ-compression-support-loop.patch \
            file://CVE-2015-7498-Avoid-processing-entities-after-encoding-conversion-.patch \
+           file://0001-CVE-2015-7497-Avoid-an-heap-buffer-overflow-in-xmlDi.patch \
           "
 
 BINCONFIG = "${bindir}/xml2-config"

meta/recipes-core/libxml/libxml2/0001-CVE-2015-7497-Avoid-an-heap-buffer-overflow-in-xmlDi.patch

@@ -0,0 +1,40 @@
+From 6360a31a84efe69d155ed96306b9a931a40beab9 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
+
+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
+
+Upstream-Status: Backport
+
+CVE-2015-7497
+
+Signed-off-by: Armin Kuster <akuster@mvista.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;
+-- 
+2.3.5
+