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From 8f30bdff69edac9075f4663ce3b56b0c52d48ce6 Mon Sep 17 00:00:00 2001
From: Peter Simons <psimons@suse.com>
Date: Fri, 15 Apr 2016 11:56:55 +0200
Subject: [PATCH] Add missing increments of recursion depth counter to XML
parser.
For https://bugzilla.gnome.org/show_bug.cgi?id=765207
CVE-2016-3705
The functions xmlParserEntityCheck() and xmlParseAttValueComplex() used to call
xmlStringDecodeEntities() in a recursive context without incrementing the
'depth' counter in the parser context. Because of that omission, the parser
failed to detect attribute recursions in certain documents before running out
of stack space.
Upstream-Status: Backport
CVE: CVE-2016-3705
Signed-off-by: Armin Kuster <akuster@mvista.com>
---
parser.c | 8 ++++++++
1 file changed, 8 insertions(+)
Index: libxml2-2.9.2/parser.c
===================================================================
--- libxml2-2.9.2.orig/parser.c
+++ libxml2-2.9.2/parser.c
@@ -144,8 +144,10 @@ xmlParserEntityCheck(xmlParserCtxtPtr ct
ent->checked = 1;
+ ++ctxt->depth;
rep = xmlStringDecodeEntities(ctxt, ent->content,
XML_SUBSTITUTE_REF, 0, 0, 0);
+ --ctxt->depth;
ent->checked = (ctxt->nbentities - oldnbent + 1) * 2;
if (rep != NULL) {
@@ -3978,8 +3980,10 @@ xmlParseEntityValue(xmlParserCtxtPtr ctx
* an entity declaration, it is bypassed and left as is.
* so XML_SUBSTITUTE_REF is not set here.
*/
+ ++ctxt->depth;
ret = xmlStringDecodeEntities(ctxt, buf, XML_SUBSTITUTE_PEREF,
0, 0, 0);
+ --ctxt->depth;
if (orig != NULL)
*orig = buf;
else
@@ -4104,9 +4108,11 @@ xmlParseAttValueComplex(xmlParserCtxtPtr
} else if ((ent != NULL) &&
(ctxt->replaceEntities != 0)) {
if (ent->etype != XML_INTERNAL_PREDEFINED_ENTITY) {
+ ++ctxt->depth;
rep = xmlStringDecodeEntities(ctxt, ent->content,
XML_SUBSTITUTE_REF,
0, 0, 0);
+ --ctxt->depth;
if (rep != NULL) {
current = rep;
while (*current != 0) { /* non input consuming */
@@ -4142,8 +4148,10 @@ xmlParseAttValueComplex(xmlParserCtxtPtr
(ent->content != NULL) && (ent->checked == 0)) {
unsigned long oldnbent = ctxt->nbentities;
+ ++ctxt->depth;
rep = xmlStringDecodeEntities(ctxt, ent->content,
XML_SUBSTITUTE_REF, 0, 0, 0);
+ --ctxt->depth;
ent->checked = (ctxt->nbentities - oldnbent + 1) * 2;
if (rep != NULL) {
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