From e91c46c7a1a904eba04e29cdf896c99cb546d989 Mon Sep 17 00:00:00 2001

From: Tomas Orsava <torsava@redhat.com>

Date: Wed, 22 Jun 2016 17:06:01 +0200

Subject: [PATCH] Disabled HTTP header injections in httplib

CVE-2016-5699 python: http protocol steam injection attack

rhbz#1303699 : https://bugzilla.redhat.com/show_bug.cgi?id=1303699

Based on an upstream change by Demian Brecht and Serhiy Storchaka

- in changeset 94951:1c45047c5102 2.7

- https://hg.python.org/cpython/rev/1c45047c5102

---

 Lib/httplib.py           | 40 +++++++++++++++++++++++++++++++++-

 Lib/test/test_httplib.py | 56 ++++++++++++++++++++++++++++++++++++++++++++++++

 2 files changed, 95 insertions(+), 1 deletion(-)

diff --git a/Lib/httplib.py b/Lib/httplib.py

index 8e02ac3..592ee57 100644

--- a/Lib/httplib.py

+++ b/Lib/httplib.py

@@ -68,6 +68,7 @@ Req-sent-unread-response       _CS_REQ_SENT       <response_class>

 from array import array

 import os

+import re

 import socket

 from sys import py3kwarning

 from urlparse import urlsplit

@@ -218,6 +219,34 @@ _MAXLINE = 65536

 # maximum amount of headers accepted

 _MAXHEADERS = 100

+# Header name/value ABNF (http://tools.ietf.org/html/rfc7230#section-3.2)

+#

+# VCHAR          = %x21-7E

+# obs-text       = %x80-FF

+# header-field   = field-name ":" OWS field-value OWS

+# field-name     = token

+# field-value    = *( field-content / obs-fold )

+# field-content  = field-vchar [ 1*( SP / HTAB ) field-vchar ]

+# field-vchar    = VCHAR / obs-text

+#

+# obs-fold       = CRLF 1*( SP / HTAB )

+#                ; obsolete line folding

+#                ; see Section 3.2.4

+

+# token          = 1*tchar

+#

+# tchar          = "!" / "#" / "$" / "%" / "&" / "'" / "*"

+#                / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~"

+#                / DIGIT / ALPHA

+#                ; any VCHAR, except delimiters

+#

+# VCHAR defined in http://tools.ietf.org/html/rfc5234#appendix-B.1

+

+# the patterns for both name and value are more leniant than RFC

+# definitions to allow for backwards compatibility

+_is_legal_header_name = re.compile(r'\A[^:\s][^:\r\n]*\Z').match

+_is_illegal_header_value = re.compile(r'\n(?![ \t])|\r(?![ \t\n])').search

+

 class HTTPMessage(mimetools.Message):

@@ -956,7 +985,16 @@ class HTTPConnection:

         if self.__state != _CS_REQ_STARTED:

             raise CannotSendHeader()

-        hdr = '%s: %s' % (header, '\r\n\t'.join([str(v) for v in values]))

+        header = '%s' % header

+        if not _is_legal_header_name(header):

+            raise ValueError('Invalid header name %r' % (header,))

+

+        values = [str(v) for v in values]

+        for one_value in values:

+            if _is_illegal_header_value(one_value):

+                raise ValueError('Invalid header value %r' % (one_value,))

+

+        hdr = '%s: %s' % (header, '\r\n\t'.join(values))

         self._output(hdr)

     def endheaders(self, message_body=None):

diff --git a/Lib/test/test_httplib.py b/Lib/test/test_httplib.py

index c29aceb..29af589 100644

--- a/Lib/test/test_httplib.py

+++ b/Lib/test/test_httplib.py

@@ -133,6 +133,33 @@ class HeaderTests(TestCase):

         conn.putheader('Content-length',42)

         self.assertTrue('Content-length: 42' in conn._buffer)

+        conn.putheader('Foo', ' bar ')

+        self.assertIn(b'Foo:  bar ', conn._buffer)

+        conn.putheader('Bar', '\tbaz\t')

+        self.assertIn(b'Bar: \tbaz\t', conn._buffer)

+        conn.putheader('Authorization', 'Bearer mytoken')

+        self.assertIn(b'Authorization: Bearer mytoken', conn._buffer)

+        conn.putheader('IterHeader', 'IterA', 'IterB')

+        self.assertIn(b'IterHeader: IterA\r\n\tIterB', conn._buffer)

+        conn.putheader('LatinHeader', b'\xFF')

+        self.assertIn(b'LatinHeader: \xFF', conn._buffer)

+        conn.putheader('Utf8Header', b'\xc3\x80')

+        self.assertIn(b'Utf8Header: \xc3\x80', conn._buffer)

+        conn.putheader('C1-Control', b'next\x85line')

+        self.assertIn(b'C1-Control: next\x85line', conn._buffer)

+        conn.putheader('Embedded-Fold-Space', 'is\r\n allowed')

+        self.assertIn(b'Embedded-Fold-Space: is\r\n allowed', conn._buffer)

+        conn.putheader('Embedded-Fold-Tab', 'is\r\n\tallowed')

+        self.assertIn(b'Embedded-Fold-Tab: is\r\n\tallowed', conn._buffer)

+        conn.putheader('Key Space', 'value')

+        self.assertIn(b'Key Space: value', conn._buffer)

+        conn.putheader('KeySpace ', 'value')

+        self.assertIn(b'KeySpace : value', conn._buffer)

+        conn.putheader(b'Nonbreak\xa0Space', 'value')

+        self.assertIn(b'Nonbreak\xa0Space: value', conn._buffer)

+        conn.putheader(b'\xa0NonbreakSpace', 'value')

+        self.assertIn(b'\xa0NonbreakSpace: value', conn._buffer)

+

     def test_ipv6host_header(self):

         # Default host header on IPv6 transaction should wrapped by [] if

         # its actual IPv6 address

@@ -152,6 +179,35 @@ class HeaderTests(TestCase):

         conn.request('GET', '/foo')

         self.assertTrue(sock.data.startswith(expected))

+    def test_invalid_headers(self):

+        conn = httplib.HTTPConnection('example.com')

+        conn.sock = FakeSocket('')

+        conn.putrequest('GET', '/')

+

+        # http://tools.ietf.org/html/rfc7230#section-3.2.4, whitespace is no

+        # longer allowed in header names

+        cases = (

+            (b'Invalid\r\nName', b'ValidValue'),

+            (b'Invalid\rName', b'ValidValue'),

+            (b'Invalid\nName', b'ValidValue'),

+            (b'\r\nInvalidName', b'ValidValue'),

+            (b'\rInvalidName', b'ValidValue'),

+            (b'\nInvalidName', b'ValidValue'),

+            (b' InvalidName', b'ValidValue'),

+            (b'\tInvalidName', b'ValidValue'),

+            (b'Invalid:Name', b'ValidValue'),

+            (b':InvalidName', b'ValidValue'),

+            (b'ValidName', b'Invalid\r\nValue'),

+            (b'ValidName', b'Invalid\rValue'),

+            (b'ValidName', b'Invalid\nValue'),

+            (b'ValidName', b'InvalidValue\r\n'),

+            (b'ValidName', b'InvalidValue\r'),

+            (b'ValidName', b'InvalidValue\n'),

+        )

+        for name, value in cases:

+            with self.assertRaisesRegexp(ValueError, 'Invalid header'):

+                conn.putheader(name, value)

+

 class BasicTest(TestCase):

     def test_status_lines(self):

-- 

2.9.0