From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Lumir Balhar <lbalhar@redhat.com>
Date: Tue, 14 Sep 2021 11:34:43 +0200
Subject: [PATCH] 00366-CVE-2021-3733.patch

00366 #
CVE-2021-3733: Fix ReDoS in urllib AbstractBasicAuthHandler

Fix Regular Expression Denial of Service (ReDoS) vulnerability in
urllib2.AbstractBasicAuthHandler. The ReDoS-vulnerable regex
has quadratic worst-case complexity and it allows cause a denial of
service when identifying crafted invalid RFCs. This ReDoS issue is on
the client side and needs remote attackers to control the HTTP server.

Backported from Python 3 together with another backward-compatible
improvement of the regex from fix for CVE-2020-8492.

Co-authored-by: Yeting Li <liyt@ios.ac.cn>
---
 Lib/urllib2.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/urllib2.py b/Lib/urllib2.py
index fd19e1ae943..e286583ecba 100644
--- a/Lib/urllib2.py
+++ b/Lib/urllib2.py
@@ -858,7 +858,7 @@ class AbstractBasicAuthHandler:
 
     # allow for double- and single-quoted realm values
     # (single quotes are a violation of the RFC, but appear in the wild)
-    rx = re.compile('(?:.*,)*[ \t]*([^ \t]+)[ \t]+'
+    rx = re.compile('(?:[^,]*,)*[ \t]*([^ \t,]+)[ \t]+'
                     'realm=(["\']?)([^"\']*)\\2', re.I)
 
     # XXX could pre-emptively send auth info already accepted (RFC 2617,