[merge from 3.3] 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 #27568 Reported and patch contributed by Rémi Rampin.

diff --cc Doc/howto/urllib2.rst
Simple merge

diff --cc Doc/library/urllib.request.rst
Simple merge

diff --cc Lib/test/test_urllib.py
index e100039649e38520964c95c59440622754142db0,3b87fa315afe76937b89fa8424355474cc6c2803..87171e9b7b175cd98c07253da720157584b77da0
--- 1/Lib/test/test_urllib.py
--- 2/Lib/test/test_urllib.py
+++ b/Lib/test/test_urllib.py
@@@ -222,7 -194,20 +222,20 @@@ class ProxyTests(unittest.TestCase)
          self.env.set('NO_PROXY', 'localhost, anotherdomain.com, newdomain.com')
          self.assertTrue(urllib.request.proxy_bypass_environment('anotherdomain.com'))
  
 -class urlopen_HttpTests(unittest.TestCase, FakeHTTPMixin):
+     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."""
  
      def check_read(self, ver):

diff --cc Lib/urllib/request.py
Simple merge

diff --cc Misc/NEWS
index 2d4b4da91060f1a58fd4bca7aed70d33dc4e2122,e9a8f28f2ca040720dc3d8d6d0bca995875d1136..362b6baf35b3c7de4eb0fd3482fcd0970abbf92f
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -10,64 -10,56 +10,68 @@@ Release date: TB
  Core and Builtins
  -----------------
  
 -- Issue #25709: Fixed problem with in-place string concatenation and utf-8 cache.
 +Library
 +-------
  
 -- Issue #24407: Fix crash when dict is mutated while being updated.
++- 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 #24097: Fixed crash in object.__reduce__() if slot name is freed inside
 -  __getattr__.
 +Tests
 +-----
  
 -- Issue #24096: Make warnings.warn_explicit more robust against mutation of the
 -  warnings.filters list.
 +- Issue #27369: In test_pyexpat, avoid testing an error message detail that
 +  changed in Expat 2.2.0.
  
 -- Issue #24044: Fix possible null pointer dereference in list.sort in out of
 -  memory conditions.
  
 -- Issue #23055: Fixed a buffer overflow in PyUnicode_FromFormatV.  Analysis
 -  and fix by Guido Vranken.
 +What's New in Python 3.4.5?
 +===========================
  
 -Library
 --------
 +Release date: 2016-06-26
  
 -- 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.
 +Tests
 +-----
  
 -- Issue #24521: Fix possible integer overflows in the pickle module.
 +- Issue #26867: Ubuntu's openssl OP_NO_SSLv3 is forced on by default; fix test.
  
 -- Issue #22931: Allow '[' and ']' in cookie values.
  
 -- Issue #24094: Fix possible crash in json.encode with poorly behaved dict
 -  subclasses.
 +What's New in Python 3.4.5rc1?
 +==============================
  
 -- Issue #23367: Fix possible overflows in the unicodedata module.
 +Release date: 2016-06-11
  
 -- Issue #23361: Fix possible overflow in Windows subprocess creation code.
 +Core and Builtins
 +-----------------
  
 -- Issue #23363: Fix possible overflow in itertools.permutations.
 +- Issue #26478: Fix semantic bugs when using binary operators with dictionary
 +  views and tuples.
  
 -- Issue #23364: Fix possible overflow in itertools.product.
 +- Issue #26171: Fix possible integer overflow and heap corruption in
 +  zipimporter.get_data().
  
 -- Issue #23369: Fixed possible integer overflow in
 -  _json.encode_basestring_ascii.
 +Library
 +-------
  
 -- Issue #23366: Fixed possible integer overflow in itertools.combinations.
 +- Issue #26556: Update expat to 2.1.1, fixes CVE-2015-1283.
  
 -- Issue #23365: Fixed possible integer overflow in
 -  itertools.combinations_with_replacement.
 +- Fix TLS stripping vulnerability in smptlib, CVE-2016-0772.  Reported by Team
 +  Oststrom
  
 -C API
 ------
 +- Issue #25939: On Windows open the cert store readonly in ssl.enum_certificates.
  
 -- Issue #23998: PyImport_ReInitLock() now checks for lock allocation error
 +- Issue #26012: Don't traverse into symlinks for ** pattern in
 +  pathlib.Path.[r]glob().
 +
 +- Issue #24120: Ignore PermissionError when traversing a tree with
 +  pathlib.Path.[r]glob().  Patch by Ulrich Petri.
 +
 +- Skip getaddrinfo if host is already resolved.
 +  Patch by A. Jesse Jiryu Davis.
 +
 +- Add asyncio.timeout() context manager.
 +
 +- Issue #26050: Add asyncio.StreamReader.readuntil() method.
 +  Patch by Марк Коренберг.
  
  Tests
  -----