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From 5e0700418dc27b645edbe33c744daff93cd66618 Mon Sep 17 00:00:00 2001
From: Senthil Kumaran <senthil@uthcode.com>
Date: Sat, 30 Jul 2016 23:24:16 -0700
Subject: [PATCH] Prevent HTTPoxy attack (CVE-2016-1000110)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Ignore the HTTP_PROXY variable when REQUEST_METHOD environment is set, which
indicates that the script is in CGI mode.
Issue #27568 Reported and patch contributed by Rémi Rampin.
Upstream-Status: Backport
CVE: CVE-2016-1000110
Signed-off-by: Armin Kuster <akuster@mvista.com>
---
Doc/howto/urllib2.rst | 5 +++++
Doc/library/urllib.request.rst | 13 +++++++++++++
Lib/test/test_urllib.py | 13 +++++++++++++
Lib/urllib/request.py | 7 +++++++
Misc/NEWS | 4 ++++
5 files changed, 42 insertions(+)
Index: Python-3.5.1/Doc/howto/urllib2.rst
===================================================================
--- Python-3.5.1.orig/Doc/howto/urllib2.rst
+++ Python-3.5.1/Doc/howto/urllib2.rst
@@ -538,6 +538,11 @@ setting up a `Basic Authentication`_ han
through a proxy. However, this can be enabled by extending urllib.request as
shown in the recipe [#]_.
+.. note::
+
+ `HTTP_PROXY`` will be ignored if a variable ``REQUEST_METHOD`` is set; see
+ the documentation on :func:`~urllib.request.getproxies`.
+
Sockets and Layers
==================
Index: Python-3.5.1/Doc/library/urllib.request.rst
===================================================================
--- Python-3.5.1.orig/Doc/library/urllib.request.rst
+++ Python-3.5.1/Doc/library/urllib.request.rst
@@ -166,6 +166,14 @@ The :mod:`urllib.request` module defines
cannot find it, looks for proxy information from Mac OSX System
Configuration for Mac OS X and Windows Systems Registry for Windows.
+ .. note::
+
+ If the environment variable ``REQUEST_METHOD`` is set, which usually
+ indicates your script is running in a CGI environment, the environment
+ variable ``HTTP_PROXY`` (uppercase ``_PROXY``) will be ignored. This is
+ because that variable can be injected by a client using the "Proxy:" HTTP
+ header. If you need to use an HTTP proxy in a CGI environment use
+ ``ProxyHandler`` explicitly.
The following classes are provided:
@@ -275,6 +283,11 @@ The following classes are provided:
To disable autodetected proxy pass an empty dictionary.
+ .. note::
+
+ ``HTTP_PROXY`` will be ignored if a variable ``REQUEST_METHOD`` is set;
+ see the documentation on :func:`~urllib.request.getproxies`.
+
.. class:: HTTPPasswordMgr()
Index: Python-3.5.1/Lib/urllib/request.py
===================================================================
--- Python-3.5.1.orig/Lib/urllib/request.py
+++ Python-3.5.1/Lib/urllib/request.py
@@ -2394,6 +2394,13 @@ def getproxies_environment():
name = name.lower()
if value and name[-6:] == '_proxy':
proxies[name[:-6]] = value
+
+ # CVE-2016-1000110 - If we are running as CGI script, forget HTTP_PROXY
+ # (non-all-lowercase) as it may be set from the web server by a "Proxy:"
+ # header from the client
+ if 'REQUEST_METHOD' in os.environ:
+ proxies.pop('http', None)
+
return proxies
def proxy_bypass_environment(host):
Index: Python-3.5.1/Misc/NEWS
===================================================================
--- Python-3.5.1.orig/Misc/NEWS
+++ Python-3.5.1/Misc/NEWS
@@ -1266,6 +1266,10 @@ Library
lines from the code object, fixing an issue when a lambda function is used as
decorator argument. Patch by Thomas Ballinger and Allison Kaptur.
+- Issue #27568: Prevent HTTPoxy attack (CVE-2016-1000110). Ignore the
+ HTTP_PROXY variable when REQUEST_METHOD environment is set, which indicates
+ that the script is in CGI mode.
+
- Issue #24521: Fix possible integer overflows in the pickle module.
- Issue #22931: Allow '[' and ']' in cookie values.
Index: Python-3.5.1/Lib/test/test_urllib.py
===================================================================
--- Python-3.5.1.orig/Lib/test/test_urllib.py
+++ Python-3.5.1/Lib/test/test_urllib.py
@@ -224,6 +224,18 @@ class ProxyTests(unittest.TestCase):
# List of no_proxies with space.
self.env.set('NO_PROXY', 'localhost, anotherdomain.com, newdomain.com')
self.assertTrue(urllib.request.proxy_bypass_environment('anotherdomain.com'))
+ def test_proxy_cgi_ignore(self):
+ try:
+ self.env.set('HTTP_PROXY', 'http://somewhere:3128')
+ proxies = urllib.request.getproxies_environment()
+ self.assertEqual('http://somewhere:3128', proxies['http'])
+ self.env.set('REQUEST_METHOD', 'GET')
+ proxies = urllib.request.getproxies_environment()
+ self.assertNotIn('http', proxies)
+ finally:
+ self.env.unset('REQUEST_METHOD')
+ self.env.unset('HTTP_PROXY')
+
class urlopen_HttpTests(unittest.TestCase, FakeHTTPMixin, FakeFTPMixin):
"""Test urlopen() opening a fake http connection."""
|
