Subject: Do not fetch external parameter entities
From: Daniel Veillard <[email-masked]>
Date: Tue, 22 Apr 2014 15:30:56 +0800

Unless explicitely asked for when validating or replacing entities
with their value. Problem pointed out by Daniel Berrange <[email-masked]>

Upstream-Status: Backport
Reference: https://access.redhat.com/security/cve/CVE-2014-0191

Signed-off-by: Daniel Veillard <[email-masked]>
Signed-off-by: Maxin B. John <[email-masked]>
---
diff -Naur libxml2-2.9.1-orig/parser.c libxml2-2.9.1/parser.c
--- libxml2-2.9.1-orig/parser.c	2013-04-16 15:39:18.000000000 +0200
+++ libxml2-2.9.1/parser.c	2014-05-07 13:35:46.883687946 +0200
@@ -2595,6 +2595,20 @@
 		    xmlCharEncoding enc;
 
 		    /*
+		     * Note: external parsed entities will not be loaded, it is
+		     * not required for a non-validating parser, unless the
+		     * option of validating, or substituting entities were
+		     * given. Doing so is far more secure as the parser will
+		     * only process data coming from the document entity by
+		     * default.
+		     */
+                    if ((entity->etype == XML_EXTERNAL_PARAMETER_ENTITY) &&
+		        ((ctxt->options & XML_PARSE_NOENT) == 0) &&
+			((ctxt->options & XML_PARSE_DTDVALID) == 0) &&
+			(ctxt->validate == 0))
+			return;
+
+		    /*
 		     * handle the extra spaces added before and after
 		     * c.f. http://www.w3.org/TR/REC-xml#as-PE
 		     * this is done independently.