File CVE-2021-3733-ReDoS-urllib-AbstractBasicAuthHan... of Package python3-doc.32356

Overview Repositories Revisions Requests Users Attributes Meta

File CVE-2021-3733-ReDoS-urllib-AbstractBasicAuthHandler.patch of Package python3-doc.32356

From 3fbe96123aeb66664fa547a8f6022efa2dc8788f Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Thu, 6 May 2021 10:00:07 -0700
Subject: [PATCH] bpo-43075: Fix ReDoS in urllib AbstractBasicAuthHandler
 (GH-24391) (GH-25250)

Fix Regular Expression Denial of Service (ReDoS) vulnerability in
urllib.request.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.
(cherry picked from commit 7215d1ae25525c92b026166f9d5cac85fb1defe1)

Co-authored-by: Yeting Li <liyt@ios.ac.cn>
---
 Lib/urllib/request.py                                              |    2 +-
 Misc/NEWS.d/next/Security/2021-01-31-05-28-14.bpo-43075.DoAXqO.rst |    1 +
 2 files changed, 2 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Security/2021-01-31-05-28-14.bpo-43075.DoAXqO.rst

--- a/Lib/urllib/request.py
+++ b/Lib/urllib/request.py
@@ -843,7 +843,7 @@ 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,
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2021-01-31-05-28-14.bpo-43075.DoAXqO.rst
@@ -0,0 +1 @@
+Fix Regular Expression Denial of Service (ReDoS) vulnerability in :class:`urllib.request.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.

Places

File CVE-2021-3733-ReDoS-urllib-AbstractBasicAuthHandler.patch of Package python3-doc.32356

Places