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From 899a5d9f0ed13b8e32449a08a361e0de127dd961 Mon Sep 17 00:00:00 2001
From: Nick Wellnhofer <wellnhofer@aevum.de>
Date: Tue, 25 Jul 2017 14:59:49 +0200
Subject: [PATCH] Detect infinite recursion in parameter entities
When expanding a parameter entity in a DTD, infinite recursion could
lead to an infinite loop or memory exhaustion.
Thanks to Wei Lei for the first of many reports.
Fixes bug 759579.
CVE: CVE-2017-16932
Upstream-Status: Backport [https://github.com/GNOME/libxml2/commit/899a5d9f0ed13b8e32449a08a361e0de127dd961]
Signed-off-by: Andreas Wellving <andreas.wellving@enea.com>
---
parser.c | 11 ++++++++++-
result/errors/759579.xml | 0
result/errors/759579.xml.err | 6 ++++++
result/errors/759579.xml.str | 7 +++++++
test/errors/759579.xml | 11 +++++++++++
5 files changed, 34 insertions(+), 1 deletion(-)
create mode 100644 result/errors/759579.xml
create mode 100644 result/errors/759579.xml.err
create mode 100644 result/errors/759579.xml.str
create mode 100644 test/errors/759579.xml
diff --git a/parser.c b/parser.c
index 6286cad..51452a2 100644
--- a/parser.c
+++ b/parser.c
@@ -2250,6 +2250,13 @@ xmlPushInput(xmlParserCtxtPtr ctxt, xmlParserInputPtr input) {
xmlGenericError(xmlGenericErrorContext,
"Pushing input %d : %.30s\n", ctxt->inputNr+1, input->cur);
}
+ if (((ctxt->inputNr > 40) && ((ctxt->options & XML_PARSE_HUGE) == 0)) ||
+ (ctxt->inputNr > 1024)) {
+ xmlFatalErr(ctxt, XML_ERR_ENTITY_LOOP, NULL);
+ while (ctxt->inputNr > 1)
+ xmlFreeInputStream(inputPop(ctxt));
+ return(-1);
+ }
ret = inputPush(ctxt, input);
if (ctxt->instate == XML_PARSER_EOF)
return(-1);
@@ -7916,8 +7923,10 @@ xmlParsePEReference(xmlParserCtxtPtr ctxt)
* c.f. http://www.w3.org/TR/REC-xml#as-PE
*/
input = xmlNewEntityInputStream(ctxt, entity);
- if (xmlPushInput(ctxt, input) < 0)
+ if (xmlPushInput(ctxt, input) < 0) {
+ xmlFreeInputStream(input);
return;
+ }
if ((entity->etype == XML_EXTERNAL_PARAMETER_ENTITY) &&
(CMP5(CUR_PTR, '<', '?', 'x', 'm', 'l')) &&
(IS_BLANK_CH(NXT(5)))) {
diff --git a/result/errors/759579.xml b/result/errors/759579.xml
new file mode 100644
index 0000000..e69de29
diff --git a/result/errors/759579.xml.err b/result/errors/759579.xml.err
new file mode 100644
index 0000000..288026e
--- /dev/null
+++ b/result/errors/759579.xml.err
@@ -0,0 +1,6 @@
+Entity: line 2: parser error : Detected an entity reference loop
+ %z; %z; %z; %z; %z;
+ ^
+Entity: line 2:
+ %z; %z; %z; %z; %z;
+ ^
diff --git a/result/errors/759579.xml.str b/result/errors/759579.xml.str
new file mode 100644
index 0000000..09408f5
--- /dev/null
+++ b/result/errors/759579.xml.str
@@ -0,0 +1,7 @@
+Entity: line 2: parser error : Detected an entity reference loop
+ %z; %z; %z; %z; %z;
+ ^
+Entity: line 2:
+ %z; %z; %z; %z; %z;
+ ^
+./test/errors/759579.xml : failed to parse
diff --git a/test/errors/759579.xml b/test/errors/759579.xml
new file mode 100644
index 0000000..7fadd70
--- /dev/null
+++ b/test/errors/759579.xml
@@ -0,0 +1,11 @@
+<!DOCTYPE doc [
+ <!ENTITY % z '
+ %z; %z; %z; %z; %z;
+ %z; %z; %z; %z; %z;
+ %z; %z; %z; %z; %z;
+ %z; %z; %z; %z; %z;
+ %z; %z; %z; %z; %z;
+ '>
+ %z;
+]>
+<doc/>
--
2.7.4
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