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synced 2024-12-22 17:16:24 +00:00
Fixed #24496 -- Added CSRF Referer checking against CSRF_COOKIE_DOMAIN.
Thanks Seth Gottlieb for help with the documentation and Carl Meyer and Joshua Kehn for reviews.
This commit is contained in:
parent
535809e121
commit
b0c56b895f
@ -16,6 +16,7 @@ from django.utils.datastructures import ImmutableList, MultiValueDict
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from django.utils.encoding import (
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escape_uri_path, force_bytes, force_str, force_text, iri_to_uri,
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)
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from django.utils.http import is_same_domain
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from django.utils.six.moves.urllib.parse import (
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parse_qsl, quote, urlencode, urljoin, urlsplit,
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)
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@ -546,15 +547,7 @@ def validate_host(host, allowed_hosts):
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host = host[:-1] if host.endswith('.') else host
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for pattern in allowed_hosts:
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pattern = pattern.lower()
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match = (
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pattern == '*' or
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pattern.startswith('.') and (
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host.endswith(pattern) or host == pattern[1:]
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) or
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pattern == host
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)
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if match:
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if pattern == '*' or is_same_domain(host, pattern):
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return True
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return False
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@ -14,7 +14,8 @@ from django.core.urlresolvers import get_callable
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from django.utils.cache import patch_vary_headers
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from django.utils.crypto import constant_time_compare, get_random_string
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from django.utils.encoding import force_text
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from django.utils.http import same_origin
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from django.utils.http import is_same_domain
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from django.utils.six.moves.urllib.parse import urlparse
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logger = logging.getLogger('django.request')
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@ -22,6 +23,8 @@ REASON_NO_REFERER = "Referer checking failed - no Referer."
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REASON_BAD_REFERER = "Referer checking failed - %s does not match any trusted origins."
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REASON_NO_CSRF_COOKIE = "CSRF cookie not set."
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REASON_BAD_TOKEN = "CSRF token missing or incorrect."
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REASON_MALFORMED_REFERER = "Referer checking failed - Referer is malformed."
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REASON_INSECURE_REFERER = "Referer checking failed - Referer is insecure while host is secure."
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CSRF_KEY_LENGTH = 32
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@ -154,15 +157,35 @@ class CsrfViewMiddleware(object):
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if referer is None:
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return self._reject(request, REASON_NO_REFERER)
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referer = urlparse(referer)
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# Make sure we have a valid URL for Referer.
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if '' in (referer.scheme, referer.netloc):
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return self._reject(request, REASON_MALFORMED_REFERER)
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# Ensure that our Referer is also secure.
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if referer.scheme != 'https':
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return self._reject(request, REASON_INSECURE_REFERER)
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# If there isn't a CSRF_COOKIE_DOMAIN, assume we need an exact
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# match on host:port. If not, obey the cookie rules.
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if settings.CSRF_COOKIE_DOMAIN is None:
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# request.get_host() includes the port.
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good_referer = request.get_host()
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else:
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good_referer = settings.CSRF_COOKIE_DOMAIN
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server_port = request.META['SERVER_PORT']
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if server_port not in ('443', '80'):
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good_referer = '%s:%s' % (good_referer, server_port)
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# Here we generate a list of all acceptable HTTP referers,
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# including the current host since that has been validated
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# upstream.
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good_hosts = list(settings.CSRF_TRUSTED_ORIGINS)
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# Note that request.get_host() includes the port.
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good_hosts.append(request.get_host())
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good_referers = ['https://{0}/'.format(host) for host in good_hosts]
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if not any(same_origin(referer, host) for host in good_referers):
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reason = REASON_BAD_REFERER % referer
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good_hosts.append(good_referer)
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if not any(is_same_domain(referer.netloc, host) for host in good_hosts):
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reason = REASON_BAD_REFERER % referer.geturl()
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return self._reject(request, reason)
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if csrf_token is None:
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@ -253,18 +253,24 @@ def quote_etag(etag):
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return '"%s"' % etag.replace('\\', '\\\\').replace('"', '\\"')
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def same_origin(url1, url2):
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def is_same_domain(host, pattern):
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"""
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Checks if two URLs are 'same-origin'
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Return ``True`` if the host is either an exact match or a match
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to the wildcard pattern.
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Any pattern beginning with a period matches a domain and all of its
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subdomains. (e.g. ``.example.com`` matches ``example.com`` and
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``foo.example.com``). Anything else is an exact string match.
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"""
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p1, p2 = urlparse(url1), urlparse(url2)
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try:
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o1 = (p1.scheme, p1.hostname, p1.port or PROTOCOL_TO_PORT[p1.scheme])
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o2 = (p2.scheme, p2.hostname, p2.port or PROTOCOL_TO_PORT[p2.scheme])
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return o1 == o2
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except (ValueError, KeyError):
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if not pattern:
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return False
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pattern = pattern.lower()
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return (
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pattern[0] == '.' and (host.endswith(pattern) or host == pattern[1:]) or
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pattern == host
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)
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def is_safe_url(url, host=None):
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"""
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@ -257,11 +257,19 @@ The CSRF protection is based on the following things:
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due to the fact that HTTP 'Set-Cookie' headers are (unfortunately) accepted
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by clients that are talking to a site under HTTPS. (Referer checking is not
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done for HTTP requests because the presence of the Referer header is not
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reliable enough under HTTP.) Expanding the accepted referers beyond the
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current host can be done with the :setting:`CSRF_TRUSTED_ORIGINS` setting.
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reliable enough under HTTP.)
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This ensures that only forms that have originated from your Web site can be used
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to POST data back.
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If the :setting:`CSRF_COOKIE_DOMAIN` setting is set, the referer is compared
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against it. This setting supports subdomains. For example,
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``CSRF_COOKIE_DOMAIN = '.example.com'`` will allow POST requests from
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``www.example.com`` and ``api.example.com``. If the setting is not set, then
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the referer must match the HTTP ``Host`` header.
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Expanding the accepted referers beyond the current host or cookie domain can
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be done with the :setting:`CSRF_TRUSTED_ORIGINS` setting.
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This ensures that only forms that have originated from trusted domains can be
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used to POST data back.
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It deliberately ignores GET requests (and other requests that are defined as
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'safe' by :rfc:`2616`). These requests ought never to have any potentially
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@ -269,6 +277,10 @@ dangerous side effects , and so a CSRF attack with a GET request ought to be
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harmless. :rfc:`2616` defines POST, PUT and DELETE as 'unsafe', and all other
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methods are assumed to be unsafe, for maximum protection.
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.. versionchanged:: 1.9
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Checking against the :setting:`CSRF_COOKIE_DOMAIN` setting was added.
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Caching
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=======
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@ -444,6 +444,8 @@ header that matches the origin present in the ``Host`` header. This prevents,
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for example, a ``POST`` request from ``subdomain.example.com`` from succeeding
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against ``api.example.com``. If you need cross-origin unsafe requests over
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HTTPS, continuing the example, add ``"subdomain.example.com"`` to this list.
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The setting also supports subdomains, so you could add ``".example.com"``, for
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example, to allow access from all subdomains of ``example.com``.
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.. setting:: DATABASES
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@ -516,6 +516,10 @@ CSRF
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* The request header's name used for CSRF authentication can be customized
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with :setting:`CSRF_HEADER_NAME`.
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* The CSRF referer header is now validated against the
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:setting:`CSRF_COOKIE_DOMAIN` setting if set. See :ref:`how-csrf-works` for
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details.
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* The new :setting:`CSRF_TRUSTED_ORIGINS` setting provides a way to allow
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cross-origin unsafe requests (e.g. ``POST``) over HTTPS.
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@ -295,7 +295,7 @@ class CsrfViewMiddlewareTest(SimpleTestCase):
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csrf_cookie = resp2.cookies[settings.CSRF_COOKIE_NAME]
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self._check_token_present(resp, csrf_id=csrf_cookie.value)
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@override_settings(ALLOWED_HOSTS=['www.example.com'])
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@override_settings(DEBUG=True)
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def test_https_bad_referer(self):
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"""
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Test that a POST HTTPS request with a bad referer is rejected
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@ -304,27 +304,50 @@ class CsrfViewMiddlewareTest(SimpleTestCase):
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req._is_secure_override = True
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req.META['HTTP_HOST'] = 'www.example.com'
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req.META['HTTP_REFERER'] = 'https://www.evil.org/somepage'
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req2 = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertIsNotNone(req2)
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self.assertEqual(403, req2.status_code)
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req.META['SERVER_PORT'] = '443'
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response = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertContains(
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response,
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'Referer checking failed - https://www.evil.org/somepage does not '
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'match any trusted origins.',
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status_code=403,
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)
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@override_settings(ALLOWED_HOSTS=['www.example.com'])
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@override_settings(DEBUG=True)
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def test_https_malformed_referer(self):
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"""
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A POST HTTPS request with a bad referer is rejected.
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"""
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malformed_referer_msg = 'Referer checking failed - Referer is malformed.'
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req = self._get_POST_request_with_token()
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req._is_secure_override = True
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req.META['HTTP_HOST'] = 'www.example.com'
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req.META['HTTP_REFERER'] = 'http://http://www.example.com/'
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req2 = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertIsNotNone(req2)
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self.assertEqual(403, req2.status_code)
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response = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertContains(
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response,
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'Referer checking failed - Referer is insecure while host is secure.',
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status_code=403,
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)
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# Empty
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req.META['HTTP_REFERER'] = ''
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response = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertContains(response, malformed_referer_msg, status_code=403)
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# Non-ASCII
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req.META['HTTP_REFERER'] = b'\xd8B\xf6I\xdf'
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req2 = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertIsNotNone(req2)
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self.assertEqual(403, req2.status_code)
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response = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertContains(response, malformed_referer_msg, status_code=403)
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# missing scheme
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# >>> urlparse('//example.com/')
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# ParseResult(scheme='', netloc='example.com', path='/', params='', query='', fragment='')
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req.META['HTTP_REFERER'] = '//example.com/'
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response = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertContains(response, malformed_referer_msg, status_code=403)
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# missing netloc
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# >>> urlparse('https://')
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# ParseResult(scheme='https', netloc='', path='', params='', query='', fragment='')
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req.META['HTTP_REFERER'] = 'https://'
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response = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertContains(response, malformed_referer_msg, status_code=403)
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@override_settings(ALLOWED_HOSTS=['www.example.com'])
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def test_https_good_referer(self):
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@ -365,6 +388,62 @@ class CsrfViewMiddlewareTest(SimpleTestCase):
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req2 = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertIsNone(req2)
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@override_settings(ALLOWED_HOSTS=['www.example.com'], CSRF_TRUSTED_ORIGINS=['.example.com'])
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def test_https_csrf_wildcard_trusted_origin_allowed(self):
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"""
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A POST HTTPS request with a referer that matches a CSRF_TRUSTED_ORIGINS
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wilcard is accepted.
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"""
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req = self._get_POST_request_with_token()
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req._is_secure_override = True
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req.META['HTTP_HOST'] = 'www.example.com'
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req.META['HTTP_REFERER'] = 'https://dashboard.example.com'
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response = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertIsNone(response)
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@override_settings(ALLOWED_HOSTS=['www.example.com'], CSRF_COOKIE_DOMAIN='.example.com')
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def test_https_good_referer_matches_cookie_domain(self):
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"""
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A POST HTTPS request with a good referer should be accepted from a
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subdomain that's allowed by CSRF_COOKIE_DOMAIN.
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"""
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req = self._get_POST_request_with_token()
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req._is_secure_override = True
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req.META['HTTP_REFERER'] = 'https://foo.example.com/'
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req.META['SERVER_PORT'] = '443'
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response = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertIsNone(response)
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@override_settings(ALLOWED_HOSTS=['www.example.com'], CSRF_COOKIE_DOMAIN='.example.com')
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def test_https_good_referer_matches_cookie_domain_with_different_port(self):
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"""
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A POST HTTPS request with a good referer should be accepted from a
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subdomain that's allowed by CSRF_COOKIE_DOMAIN and a non-443 port.
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"""
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req = self._get_POST_request_with_token()
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req._is_secure_override = True
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req.META['HTTP_HOST'] = 'www.example.com'
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req.META['HTTP_REFERER'] = 'https://foo.example.com:4443/'
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req.META['SERVER_PORT'] = '4443'
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response = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertIsNone(response)
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@override_settings(CSRF_COOKIE_DOMAIN='.example.com', DEBUG=True)
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def test_https_reject_insecure_referer(self):
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"""
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A POST HTTPS request from an insecure referer should be rejected.
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"""
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req = self._get_POST_request_with_token()
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req._is_secure_override = True
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req.META['HTTP_REFERER'] = 'http://example.com/'
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req.META['SERVER_PORT'] = '443'
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response = CsrfViewMiddleware().process_view(req, post_form_view, (), {})
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self.assertContains(
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response,
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'Referer checking failed - Referer is insecure while host is secure.',
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status_code=403,
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)
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def test_ensures_csrf_cookie_no_middleware(self):
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"""
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The ensure_csrf_cookie() decorator works without middleware.
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@ -10,31 +10,6 @@ from django.utils.datastructures import MultiValueDict
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class TestUtilsHttp(unittest.TestCase):
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def test_same_origin_true(self):
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# Identical
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self.assertTrue(http.same_origin('http://foo.com/', 'http://foo.com/'))
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# One with trailing slash - see #15617
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self.assertTrue(http.same_origin('http://foo.com', 'http://foo.com/'))
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self.assertTrue(http.same_origin('http://foo.com/', 'http://foo.com'))
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# With port
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self.assertTrue(http.same_origin('https://foo.com:8000', 'https://foo.com:8000/'))
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# No port given but according to RFC6454 still the same origin
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self.assertTrue(http.same_origin('http://foo.com', 'http://foo.com:80/'))
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self.assertTrue(http.same_origin('https://foo.com', 'https://foo.com:443/'))
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def test_same_origin_false(self):
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# Different scheme
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self.assertFalse(http.same_origin('http://foo.com', 'https://foo.com'))
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# Different host
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self.assertFalse(http.same_origin('http://foo.com', 'http://goo.com'))
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# Different host again
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self.assertFalse(http.same_origin('http://foo.com', 'http://foo.com.evil.com'))
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# Different port
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self.assertFalse(http.same_origin('http://foo.com:8000', 'http://foo.com:8001'))
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# No port given
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self.assertFalse(http.same_origin('http://foo.com', 'http://foo.com:8000/'))
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self.assertFalse(http.same_origin('https://foo.com', 'https://foo.com:8000/'))
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def test_urlencode(self):
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# 2-tuples (the norm)
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result = http.urlencode((('a', 1), ('b', 2), ('c', 3)))
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@ -157,6 +132,25 @@ class TestUtilsHttp(unittest.TestCase):
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http.urlunquote_plus('Paris+&+Orl%C3%A9ans'),
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'Paris & Orl\xe9ans')
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def test_is_same_domain_good(self):
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for pair in (
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('example.com', 'example.com'),
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('example.com', '.example.com'),
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('foo.example.com', '.example.com'),
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('example.com:8888', 'example.com:8888'),
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('example.com:8888', '.example.com:8888'),
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('foo.example.com:8888', '.example.com:8888'),
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):
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self.assertTrue(http.is_same_domain(*pair))
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def test_is_same_domain_bad(self):
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for pair in (
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('example2.com', 'example.com'),
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('foo.example.com', 'example.com'),
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('example.com:9999', 'example.com:8888'),
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):
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self.assertFalse(http.is_same_domain(*pair))
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class ETagProcessingTests(unittest.TestCase):
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def test_parsing(self):
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