Fixed a security issue in http redirects. Disclosure and new release forthcoming.

Author: apollo13

django/http/__init__.py

@@ -11,10 +11,10 @@
 from io import BytesIO
 from pprint import pformat
 try:
- from urllib.parse import quote, parse_qsl, urlencode, urljoin
+ from urllib.parse import quote, parse_qsl, urlencode, urljoin, urlparse
 except ImportError: # Python 2
  from urllib import quote, urlencode
- from urlparse import parse_qsl, urljoin
+ from urlparse import parse_qsl, urljoin, urlparse
 
 from django.utils.six.moves import http_cookies
 # Some versions of Python 2.7 and later won't need this encoding bug fix:
@@ -80,7 +80,7 @@ def _BaseCookie__set(self, key, real_value, coded_value):
 
 from django.conf import settings
 from django.core import signing
-from django.core.exceptions import ImproperlyConfigured
+from django.core.exceptions import ImproperlyConfigured, SuspiciousOperation
 from django.core.files import uploadhandler
 from django.http.multipartparser import MultiPartParser
 from django.http.utils import *
@@ -689,20 +689,22 @@ def tell(self):
  raise Exception("This %s instance cannot tell its position" % self.__class__)
  return sum([len(chunk) for chunk in self])
 
-class HttpResponseRedirect(HttpResponse):
- status_code = 302
+class HttpResponseRedirectBase(HttpResponse):
+ allowed_schemes = ['http', 'https', 'ftp']
 
  def __init__(self, redirect_to):
- super(HttpResponseRedirect, self).__init__()
+ parsed = urlparse(redirect_to)
+ if parsed.scheme and parsed.scheme not in self.allowed_schemes:
+ raise SuspiciousOperation("Unsafe redirect to URL with protocol '%s'" % parsed.scheme)
+ super(HttpResponseRedirectBase, self).__init__()
  self['Location'] = iri_to_uri(redirect_to)
+ 
+class HttpResponseRedirect(HttpResponseRedirectBase):
+ status_code = 302
 
-class HttpResponsePermanentRedirect(HttpResponse):
+class HttpResponsePermanentRedirect(HttpResponseRedirectBase):
  status_code = 301
 
- def __init__(self, redirect_to):
- super(HttpResponsePermanentRedirect, self).__init__()
- self['Location'] = iri_to_uri(redirect_to)
-
 class HttpResponseNotModified(HttpResponse):
  status_code = 304
 

tests/regressiontests/httpwrappers/tests.py

@@ -4,8 +4,11 @@
 import copy
 import pickle
 
-from django.http import (QueryDict, HttpResponse, SimpleCookie, BadHeaderError,
- parse_cookie)
+from django.core.exceptions import SuspiciousOperation
+from django.http import (QueryDict, HttpResponse, HttpResponseRedirect,
+ HttpResponsePermanentRedirect,
+ SimpleCookie, BadHeaderError,
+ parse_cookie)
 from django.utils import unittest
 
 
@@ -309,6 +312,18 @@ def test_file_interface(self):
  r = HttpResponse(['abc'])
  self.assertRaises(Exception, r.write, 'def')
 
+ def test_unsafe_redirect(self):
+ bad_urls = [
+ 'data:text/html,<script>window.alert("xss")</script>',
+ 'mailto:test@example.com',
+ 'file:///etc/passwd',
+ ]
+ for url in bad_urls:
+ self.assertRaises(SuspiciousOperation,
+ HttpResponseRedirect, url)
+ self.assertRaises(SuspiciousOperation,
+ HttpResponsePermanentRedirect, url)
+
 
 class CookieTests(unittest.TestCase):
  def test_encode(self):