From 3a184cc875709d4324d234a4b939d614a2c9bb0f Mon Sep 17 00:00:00 2001 From: Charalampos Stratakis Date: Mon, 1 Aug 2016 11:20:11 +0200 Subject: [PATCH] =?UTF-8?q?Fix=20for=20CVE-2016-1000110=20http://bugs.pyth?= =?UTF-8?q?on.org/issue27568=20Based=20on=20the=20patch=20by=20R=C3=A9mi?= =?UTF-8?q?=20Rampin?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- Doc/howto/urllib2.rst | 5 +++++ Doc/library/urllib.rst | 10 ++++++++++ Doc/library/urllib2.rst | 4 ++++ Lib/test/test_urllib.py | 12 ++++++++++++ Lib/urllib.py | 9 +++++++++ 5 files changed, 40 insertions(+) diff --git a/Doc/howto/urllib2.rst b/Doc/howto/urllib2.rst index f84bf08..6542846 100644 --- a/Doc/howto/urllib2.rst +++ b/Doc/howto/urllib2.rst @@ -523,6 +523,11 @@ setting up a `Basic Authentication`_ handler : :: through a proxy. However, this can be enabled by extending urllib2 as shown in the recipe [#]_. +.. note:: + + ``HTTP_PROXY`` will be ignored if a variable ``REQUEST_METHOD`` is set; see + the documentation on :func:`~urllib.getproxies`. + Sockets and Layers ================== diff --git a/Doc/library/urllib.rst b/Doc/library/urllib.rst index c7d200d..3b9876e 100644 --- a/Doc/library/urllib.rst +++ b/Doc/library/urllib.rst @@ -280,6 +280,16 @@ Utility functions 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, + either use ``ProxyHandler`` explicitly, or make sure the variable name + is in lowercase (or at least the ``_proxy`` suffix). + .. note:: urllib also exposes certain utility functions like splittype, splithost and others parsing url into various components. But it is recommended to use diff --git a/Doc/library/urllib2.rst b/Doc/library/urllib2.rst index 24deeb4..46fce59 100644 --- a/Doc/library/urllib2.rst +++ b/Doc/library/urllib2.rst @@ -224,6 +224,10 @@ 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.getproxies`. .. class:: HTTPPasswordMgr() diff --git a/Lib/test/test_urllib.py b/Lib/test/test_urllib.py index 3a273f8..3845012 100644 --- a/Lib/test/test_urllib.py +++ b/Lib/test/test_urllib.py @@ -161,6 +161,18 @@ class ProxyTests(unittest.TestCase): self.env.set('NO_PROXY', 'localhost, anotherdomain.com, newdomain.com') self.assertTrue(urllib.proxy_bypass_environment('anotherdomain.com')) + def test_proxy_cgi_ignore(self): + try: + self.env.set('HTTP_PROXY', 'http://somewhere:3128') + proxies = urllib.getproxies_environment() + self.assertEqual('http://somewhere:3128', proxies['http']) + self.env.set('REQUEST_METHOD', 'GET') + proxies = urllib.getproxies_environment() + self.assertNotIn('http', proxies) + finally: + self.env.unset('REQUEST_METHOD') + self.env.unset('HTTP_PROXY') + class urlopen_HttpTests(unittest.TestCase, FakeHTTPMixin): """Test urlopen() opening a fake http connection.""" diff --git a/Lib/urllib.py b/Lib/urllib.py index f9655f9..9b31df1 100644 --- a/Lib/urllib.py +++ b/Lib/urllib.py @@ -1361,11 +1361,20 @@ def getproxies_environment(): [Fancy]URLopener constructor. """ + # Get all variables proxies = {} for name, value in os.environ.items(): 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 "proxy" is lowercase, it will still be used thanks to the next block + if 'REQUEST_METHOD' in os.environ: + proxies.pop('http', None) + return proxies def proxy_bypass_environment(host): -- 2.7.4