From 82224a0b35a9b381708cd6dee990aa9c4b4db7cd Mon Sep 17 00:00:00 2001

From: Lumir Balhar <lbalhar@redhat.com>

Date: Thu, 16 Jan 2020 10:08:55 +0100

Subject: [PATCH] Fix for CVE-2018-18074

This patch contains the fix for CVE-2018-18074 and

a subsequent regression fix combined in one.

---

 sessions.py | 36 +++++++++++++++++++++++++++++-------

 utils.py    |  1 +

 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/sessions.py b/sessions.py

index bcbcc88..c65c908 100644

--- a/sessions.py

+++ b/sessions.py

@@ -17,7 +17,7 @@ from .cookies import (

     cookiejar_from_dict, extract_cookies_to_jar, RequestsCookieJar, merge_cookies)

 from .models import Request, PreparedRequest, DEFAULT_REDIRECT_LIMIT

 from .hooks import default_hooks, dispatch_hook

-from .utils import to_key_val_list, default_headers, to_native_string

+from .utils import to_key_val_list, default_headers, to_native_string, DEFAULT_PORTS

 from .exceptions import (

     TooManyRedirects, InvalidSchema, ChunkedEncodingError, ContentDecodingError)

 from .packages.urllib3._collections import RecentlyUsedContainer

@@ -85,6 +85,32 @@ def merge_hooks(request_hooks, session_hooks, dict_class=OrderedDict):

 class SessionRedirectMixin(object):

+

+    def should_strip_auth(self, old_url, new_url):

+        """Decide whether Authorization header should be removed when redirecting"""

+        old_parsed = urlparse(old_url)

+        new_parsed = urlparse(new_url)

+        if old_parsed.hostname != new_parsed.hostname:

+            return True

+        # Special case: allow http -> https redirect when using the standard

+        # ports. This isn't specified by RFC 7235, but is kept to avoid

+        # breaking backwards compatibility with older versions of requests

+        # that allowed any redirects on the same host.

+        if (old_parsed.scheme == 'http' and old_parsed.port in (80, None)

+                and new_parsed.scheme == 'https' and new_parsed.port in (443, None)):

+            return False

+

+        # Handle default port usage corresponding to scheme.

+        changed_port = old_parsed.port != new_parsed.port

+        changed_scheme = old_parsed.scheme != new_parsed.scheme

+        default_port = (DEFAULT_PORTS.get(old_parsed.scheme, None), None)

+        if (not changed_scheme and old_parsed.port in default_port

+                and new_parsed.port in default_port):

+            return False

+

+        # Standard case: root URI must match

+        return changed_port or changed_scheme

+

     def resolve_redirects(self, resp, req, stream=False, timeout=None,

                           verify=True, cert=None, proxies=None, **adapter_kwargs):

         """Receives a Response. Returns a generator of Responses."""

@@ -190,14 +216,10 @@ class SessionRedirectMixin(object):

         headers = prepared_request.headers

         url = prepared_request.url

-        if 'Authorization' in headers:

+        if 'Authorization' in headers and self.should_strip_auth(response.request.url, url):

             # If we get redirected to a new host, we should strip out any

             # authentication headers.

-            original_parsed = urlparse(response.request.url)

-            redirect_parsed = urlparse(url)

-

-            if (original_parsed.hostname != redirect_parsed.hostname):

-                del headers['Authorization']

+            del headers['Authorization']

         # .netrc might have more auth for us on our new host.

         new_auth = get_netrc_auth(url) if self.trust_env else None

diff --git a/utils.py b/utils.py

index 30a03ca..9080923 100644

--- a/utils.py

+++ b/utils.py

@@ -34,6 +34,7 @@ NETRC_FILES = ('.netrc', '_netrc')

 DEFAULT_CA_BUNDLE_PATH = certs.where()

+DEFAULT_PORTS = {'http': 80, 'https': 443}

 def dict_to_sequence(d):

     """Returns an internal sequence dictionary update."""

-- 

2.24.1