Commit c083e381 authored by Aymeric Augustin's avatar Aymeric Augustin Committed by Tim Graham
Browse files

Prevented leaking the CSRF token through caching. 

This is a security fix. Disclosure will follow shortly.
parent 8b93b314

django/middleware/cache.py

+9 −1
Original line number Diff line number Diff line
@@ -45,7 +45,8 @@ More details about how the caching works: 


from django.conf import settings

from django.core.cache import caches, DEFAULT_CACHE_ALIAS

from django.utils.cache import get_cache_key, learn_cache_key, patch_response_headers, get_max_age

from django.utils.cache import (get_cache_key, get_max_age, has_vary_header,

    learn_cache_key, patch_response_headers)





class UpdateCacheMiddleware(object):
@@ -77,8 +78,15 @@ class UpdateCacheMiddleware(object): 
        if not self._should_update_cache(request, response):

            # We don't need to update the cache, just return.

            return response



        if response.streaming or response.status_code != 200:

            return response



        # Don't cache responses that set a user-specific (and maybe security

        # sensitive) cookie in response to a cookie-less request.

        if not request.COOKIES and response.cookies and has_vary_header(response, 'Cookie'):

            return response



        # Try to get the timeout from the "max-age" section of the "Cache-

        # Control" header before reverting to using the default cache_timeout

        # length.

tests/cache/tests.py

+27 −0
Original line number Diff line number Diff line
@@ -18,11 +18,13 @@ from django.conf import settings 
from django.core import management

from django.core.cache import (cache, caches, CacheKeyWarning,

    InvalidCacheBackendError, DEFAULT_CACHE_ALIAS)

from django.core.context_processors import csrf

from django.db import connection, connections, router, transaction

from django.core.cache.utils import make_template_fragment_key

from django.http import HttpResponse, StreamingHttpResponse

from django.middleware.cache import (FetchFromCacheMiddleware,

    UpdateCacheMiddleware, CacheMiddleware)

from django.middleware.csrf import CsrfViewMiddleware

from django.template import Template

from django.template.response import TemplateResponse

from django.test import TestCase, TransactionTestCase, RequestFactory, override_settings
@@ -1741,6 +1743,10 @@ def hello_world_view(request, value): 
    return HttpResponse('Hello World %s' % value)





def csrf_view(request):

    return HttpResponse(csrf(request)['csrf_token'])





@override_settings(

    CACHE_MIDDLEWARE_ALIAS='other',

    CACHE_MIDDLEWARE_KEY_PREFIX='middlewareprefix',
@@ -1905,6 +1911,27 @@ class CacheMiddlewareTest(TestCase): 
        response = other_with_prefix_view(request, '16')

        self.assertEqual(response.content, b'Hello World 16')



    def test_sensitive_cookie_not_cached(self):

        """

        Django must prevent caching of responses that set a user-specific (and

        maybe security sensitive) cookie in response to a cookie-less request.

        """

        csrf_middleware = CsrfViewMiddleware()

        cache_middleware = CacheMiddleware()



        request = self.factory.get('/view/')

        self.assertIsNone(cache_middleware.process_request(request))



        csrf_middleware.process_view(request, csrf_view, (), {})



        response = csrf_view(request)



        response = csrf_middleware.process_response(request, response)

        response = cache_middleware.process_response(request, response)



        # Inserting a CSRF cookie in a cookie-less request prevented caching.

        self.assertIsNone(cache_middleware.process_request(request))





@override_settings(

    CACHE_MIDDLEWARE_KEY_PREFIX='settingsprefix',