gnu: libxslt: Add fix for CVE-2015-7995.

* gnu/packages/patches/libxslt-CVE-2015-7995.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/xml.scm (libxslt)[source]: Add patch.

gnu-system.am

@@ -590,6 +590,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/libxml2-id-attrs-in-xmlSetTreeDoc.patch	\
   gnu/packages/patches/libxml2-node-sort-order-pt1.patch	\
   gnu/packages/patches/libxml2-node-sort-order-pt2.patch	\
+  gnu/packages/patches/libxslt-CVE-2015-7995.patch		\
   gnu/packages/patches/lirc-localstatedir.patch			\
   gnu/packages/patches/libpthread-glibc-preparation.patch	\
   gnu/packages/patches/lm-sensors-hwmon-attrs.patch		\

gnu/packages/patches/libxslt-CVE-2015-7995.patch

@@ -0,0 +1,29 @@
+From 7ca19df892ca22d9314e95d59ce2abdeff46b617 Mon Sep 17 00:00:00 2001
+From: Daniel Veillard <veillard@redhat.com>
+Date: Thu, 29 Oct 2015 19:33:23 +0800
+Subject: [PATCH] Fix for type confusion in preprocessing attributes
+
+CVE-2015-7995 http://www.openwall.com/lists/oss-security/2015/10/27/10
+We need to check that the parent node is an element before dereferencing
+its namespace
+---
+ libxslt/preproc.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/libxslt/preproc.c b/libxslt/preproc.c
+index 0eb80a0..7f69325 100644
+--- a/libxslt/preproc.c
++++ b/libxslt/preproc.c
+@@ -2249,7 +2249,8 @@ xsltStylePreCompute(xsltStylesheetPtr style, xmlNodePtr inst) {
+ 	} else if (IS_XSLT_NAME(inst, "attribute")) {
+ 	    xmlNodePtr parent = inst->parent;
+ 
+-	    if ((parent == NULL) || (parent->ns == NULL) ||
++	    if ((parent == NULL) ||
++	        (parent->type != XML_ELEMENT_NODE) || (parent->ns == NULL) ||
+ 		((parent->ns != inst->ns) &&
+ 		 (!xmlStrEqual(parent->ns->href, inst->ns->href))) ||
+ 		(!xmlStrEqual(parent->name, BAD_CAST "attribute-set"))) {
+-- 
+2.6.3
+

gnu/packages/xml.scm

@@ -150,7 +150,8 @@ project (but it is usable outside of the Gnome platform).")
                                  version ".tar.gz"))
              (sha256
               (base32
-               "13029baw9kkyjgr7q3jccw2mz38amq7mmpr5p3bh775qawd1bisz"))))
+               "13029baw9kkyjgr7q3jccw2mz38amq7mmpr5p3bh775qawd1bisz"))
+             (patches (list (search-patch "libxslt-CVE-2015-7995.patch")))))
     (build-system gnu-build-system)
     (home-page "http://xmlsoft.org/XSLT/index.html")
     (synopsis "C library for applying XSLT stylesheets to XML documents")