Fixed is_safe_url() to reject URLs that use a scheme other than HTTP/S.

This is a security fix; disclosure to follow shortly.

django/contrib/auth/tests/test_views.py

@@ -446,7 +446,8 @@ class LoginTest(AuthViewsTestCase):
         for bad_url in ('http://example.com',
                         'https://example.com',
                         'ftp://exampel.com',
-                        '//example.com'):
+                        '//example.com',
+                        'javascript:alert("XSS")'):
 
             nasty_url = '%(url)s?%(next)s=%(bad_url)s' % {
                 'url': login_url,
@@ -467,6 +468,7 @@ class LoginTest(AuthViewsTestCase):
                          '/view?param=ftp://exampel.com',
                          'view/?param=//example.com',
                          'https:///',
+                         'HTTPS:///',
                          '//testserver/',
                          '/url%20with%20spaces/'):  # see ticket #12534
             safe_url = '%(url)s?%(next)s=%(good_url)s' % {
@@ -661,7 +663,8 @@ class LogoutTest(AuthViewsTestCase):
         for bad_url in ('http://example.com',
                         'https://example.com',
                         'ftp://exampel.com',
-                        '//example.com'):
+                        '//example.com',
+                        'javascript:alert("XSS")'):
             nasty_url = '%(url)s?%(next)s=%(bad_url)s' % {
                 'url': logout_url,
                 'next': REDIRECT_FIELD_NAME,
@@ -680,6 +683,7 @@ class LogoutTest(AuthViewsTestCase):
                          '/view?param=ftp://exampel.com',
                          'view/?param=//example.com',
                          'https:///',
+                         'HTTPS:///',
                          '//testserver/',
                          '/url%20with%20spaces/'):  # see ticket #12534
             safe_url = '%(url)s?%(next)s=%(good_url)s' % {

django/utils/http.py

@@ -252,11 +252,12 @@ def same_origin(url1, url2):
 def is_safe_url(url, host=None):
     """
     Return ``True`` if the url is a safe redirection (i.e. it doesn't point to
-    a different host).
+    a different host and uses a safe scheme).
 
     Always returns ``False`` on an empty url.
     """
     if not url:
         return False
-    netloc = urllib_parse.urlparse(url)[1]
-    return not netloc or netloc == host
+    url_info = urllib_parse.urlparse(url)
+    return (not url_info.netloc or url_info.netloc == host) and \
+        (not url_info.scheme or url_info.scheme in ['http', 'https'])