From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: AMIR <31338382+amiremohamadi@users.noreply.github.com>

Date: Sun, 19 Jul 2020 00:46:10 +0430

Subject: [PATCH] 

 00354-cve-2020-26116-http-request-method-crlf-injection-in-httplib.patch

00354 #

Reject control chars in HTTP method in httplib.putrequest to prevent

HTTP header injection

Backported from Python 3.5-3.10 (and adjusted for py2's single-module httplib):

- https://bugs.python.org/issue39603

- https://github.com/python/cpython/pull/18485 (3.10)

- https://github.com/python/cpython/pull/21946 (3.5)

Co-authored-by: AMIR <31338382+amiremohamadi@users.noreply.github.com>

---

 Lib/httplib.py                                | 16 +++++++++++++

 Lib/test/test_httplib.py                      | 23 +++++++++++++++++++

 .../2020-02-12-14-17-39.bpo-39603.Gt3RSg.rst  |  2 ++

 3 files changed, 41 insertions(+)

 create mode 100644 Misc/NEWS.d/next/Security/2020-02-12-14-17-39.bpo-39603.Gt3RSg.rst

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

index fcc4152aaf2..a63677477d5 100644

--- a/Lib/httplib.py

+++ b/Lib/httplib.py

@@ -257,6 +257,10 @@ _contains_disallowed_url_pchar_re = re.compile('[\x00-\x20\x7f-\xff]')

 #  _is_allowed_url_pchars_re = re.compile(r"^[/!$&'()*+,;=:@%a-zA-Z0-9._~-]+$")

 # We are more lenient for assumed real world compatibility purposes.

+# These characters are not allowed within HTTP method names

+# to prevent http header injection.

+_contains_disallowed_method_pchar_re = re.compile('[\x00-\x1f]')

+

 # We always set the Content-Length header for these methods because some

 # servers will otherwise respond with a 411

 _METHODS_EXPECTING_BODY = {'PATCH', 'POST', 'PUT'}

@@ -935,6 +939,8 @@ class HTTPConnection:

         else:

             raise CannotSendRequest()

+        self._validate_method(method)

+

         # Save the method for use later in the response phase

         self._method = method

@@ -1020,6 +1026,16 @@ class HTTPConnection:

         # On Python 2, request is already encoded (default)

         return request

+    def _validate_method(self, method):

+        """Validate a method name for putrequest."""

+        # prevent http header injection

+        match = _contains_disallowed_method_pchar_re.search(method)

+        if match:

+            raise ValueError(

+                    "method can't contain control characters. %r "

+                    "(found at least %r)"

+                    % (method, match.group()))

+

     def _validate_path(self, url):

         """Validate a url for putrequest."""

         # Prevent CVE-2019-9740.

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

index d8a57f73530..e295bb796ec 100644

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

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

@@ -385,6 +385,28 @@ class HeaderTests(TestCase):

                 conn.putheader(name, value)

+class HttpMethodTests(TestCase):

+    def test_invalid_method_names(self):

+        methods = (

+            'GET\r',

+            'POST\n',

+            'PUT\n\r',

+            'POST\nValue',

+            'POST\nHOST:abc',

+            'GET\nrHost:abc\n',

+            'POST\rRemainder:\r',

+            'GET\rHOST:\n',

+            '\nPUT'

+        )

+

+        for method in methods:

+            with self.assertRaisesRegexp(

+                    ValueError, "method can't contain control characters"):

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

+                conn.sock = FakeSocket(None)

+                conn.request(method=method, url="/")

+

+

 class BasicTest(TestCase):

     def test_status_lines(self):

         # Test HTTP status lines

@@ -1010,6 +1032,7 @@ class TunnelTests(TestCase):

 @test_support.reap_threads

 def test_main(verbose=None):

     test_support.run_unittest(HeaderTests, OfflineTest, BasicTest, TimeoutTest,

+                              HttpMethodTests,

                               HTTPTest, HTTPSTest, SourceAddressTest,

                               TunnelTests)

diff --git a/Misc/NEWS.d/next/Security/2020-02-12-14-17-39.bpo-39603.Gt3RSg.rst b/Misc/NEWS.d/next/Security/2020-02-12-14-17-39.bpo-39603.Gt3RSg.rst

new file mode 100644

index 00000000000..990affc3edd

--- /dev/null

+++ b/Misc/NEWS.d/next/Security/2020-02-12-14-17-39.bpo-39603.Gt3RSg.rst

@@ -0,0 +1,2 @@

+Prevent http header injection by rejecting control characters in

+http.client.putrequest(...).