Commit c5544d28 authored by Mark Striemer's avatar Mark Striemer Committed by Tim Graham
Browse files

Fixed CVE-2016-2512 -- Prevented spoofing is_safe_url() with basic auth. 

This is a security fix.
parent f4329163

django/utils/http.py

+6 −2
Original line number Diff line number Diff line
@@ -290,8 +290,12 @@ def is_safe_url(url, host=None): 
        url = url.strip()

    if not url:

        return False

    # Chrome treats \ completely as /

    url = url.replace('\\', '/')

    # Chrome treats \ completely as / in paths but it could be part of some

    # basic auth credentials so we need to check both URLs.

    return _is_safe_url(url, host) and _is_safe_url(url.replace('\\', '/'), host)





def _is_safe_url(url, host):

    # Chrome considers any URL with more than two slashes to be absolute, but

    # urlparse is not so flexible. Treat any url with three slashes as unsafe.

    if url.startswith('///'):

docs/releases/1.8.10.txt

+16 −0
Original line number Diff line number Diff line
@@ -6,6 +6,22 @@ Django 1.8.10 release notes 


Django 1.8.10 fixes two security issues and several bugs in 1.8.9.



CVE-2016-2512: Malicious redirect and possible XSS attack via user-supplied redirect URLs containing basic auth

===============================================================================================================



Django relies on user input in some cases (e.g.

:func:`django.contrib.auth.views.login` and :doc:`i18n </topics/i18n/index>`)

to redirect the user to an "on success" URL. The security check for these

redirects (namely ``django.utils.http.is_safe_url()``) considered some URLs

with basic authentication credentials "safe" when they shouldn't be.



For example, a URL like ``http://mysite.example.com\@attacker.com`` would be

considered safe if the request's host is ``http://mysite.example.com``, but

redirecting to this URL sends the user to ``attacker.com``.



Also, if a developer relies on ``is_safe_url()`` to provide safe redirect

targets and puts such a URL into a link, they could suffer from an XSS attack.



Bugfixes

========

docs/releases/1.9.3.txt

+16 −0
Original line number Diff line number Diff line
@@ -6,6 +6,22 @@ Django 1.9.3 release notes 


Django 1.9.3 fixes two security issues and several bugs in 1.9.2.



CVE-2016-2512: Malicious redirect and possible XSS attack via user-supplied redirect URLs containing basic auth

===============================================================================================================



Django relies on user input in some cases (e.g.

:func:`django.contrib.auth.views.login` and :doc:`i18n </topics/i18n/index>`)

to redirect the user to an "on success" URL. The security check for these

redirects (namely ``django.utils.http.is_safe_url()``) considered some URLs

with basic authentication credentials "safe" when they shouldn't be.



For example, a URL like ``http://mysite.example.com\@attacker.com`` would be

considered safe if the request's host is ``http://mysite.example.com``, but

redirecting to this URL sends the user to ``attacker.com``.



Also, if a developer relies on ``is_safe_url()`` to provide safe redirect

targets and puts such a URL into a link, they could suffer from an XSS attack.



Bugfixes

========

tests/utils_tests/test_http.py

+12 −0
Original line number Diff line number Diff line
@@ -97,6 +97,11 @@ class TestUtilsHttp(unittest.TestCase): 
                        'javascript:alert("XSS")',

                        '\njavascript:alert(x)',

                        '\x08//example.com',

                        r'http://otherserver\@example.com',

                        r'http:\\testserver\@example.com',

                        r'http://testserver\me:pass@example.com',

                        r'http://testserver\@example.com',

                        r'http:\\testserver\confirm\me@example.com',

                        '\n'):

            self.assertFalse(http.is_safe_url(bad_url, host='testserver'), "%s should be blocked" % bad_url)

        for good_url in ('/view/?param=http://example.com',
@@ -106,8 +111,15 @@ class TestUtilsHttp(unittest.TestCase): 
                     'https://testserver/',

                     'HTTPS://testserver/',

                     '//testserver/',

                     'http://testserver/confirm?email=me@example.com',

                     '/url%20with%20spaces/'):

            self.assertTrue(http.is_safe_url(good_url, host='testserver'), "%s should be allowed" % good_url)

        # Valid basic auth credentials are allowed.

        self.assertTrue(http.is_safe_url(r'http://user:pass@testserver/', host='user:pass@testserver'))

        # A path without host is allowed.

        self.assertTrue(http.is_safe_url('/confirm/me@example.com'))

        # Basic auth without host is not allowed.

        self.assertFalse(http.is_safe_url(r'http://testserver\@example.com'))



    def test_urlsafe_base64_roundtrip(self):

        bytestring = b'foo'