[1.11.x] Fixed CVE-2018-14574 -- Fixed open redirect possibility in CommonMiddleware.

3 files changed, 31 insertions, 0 deletions

diff --git a/tests/middleware/tests.py b/tests/middleware/tests.py
index 1d473ef558..d9d701f22a 100644
--- a/tests/middleware/tests.py
+++ b/tests/middleware/tests.py
@@ -137,6 +137,25 @@ class CommonMiddlewareTest(SimpleTestCase):
         self.assertEqual(r.status_code, 301)
         self.assertEqual(r.url, '/needsquoting%23/')
 
+    @override_settings(APPEND_SLASH=True)
+    def test_append_slash_leading_slashes(self):
+        """
+        Paths starting with two slashes are escaped to prevent open redirects.
+        If there's a URL pattern that allows paths to start with two slashes, a
+        request with path //evil.com must not redirect to //evil.com/ (appended
+        slash) which is a schemaless absolute URL. The browser would navigate
+        to evil.com/.
+        """
+        # Use 4 slashes because of RequestFactory behavior.
+        request = self.rf.get('////evil.com/security')
+        response = HttpResponseNotFound()
+        r = CommonMiddleware().process_request(request)
+        self.assertEqual(r.status_code, 301)
+        self.assertEqual(r.url, '/%2Fevil.com/security/')
+        r = CommonMiddleware().process_response(request, response)
+        self.assertEqual(r.status_code, 301)
+        self.assertEqual(r.url, '/%2Fevil.com/security/')
+
     @override_settings(APPEND_SLASH=False, PREPEND_WWW=True)
     def test_prepend_www(self):
         request = self.rf.get('/path/')
diff --git a/tests/middleware/urls.py b/tests/middleware/urls.py
index 8c6621d059..d623e7d6af 100644
--- a/tests/middleware/urls.py
+++ b/tests/middleware/urls.py
@@ -6,4 +6,6 @@ urlpatterns = [
     url(r'^noslash$', views.empty_view),
     url(r'^slash/$', views.empty_view),
     url(r'^needsquoting#/$', views.empty_view),
+    # Accepts paths with two leading slashes.
+    url(r'^(.+)/security/$', views.empty_view),
 ]
diff --git a/tests/utils_tests/test_http.py b/tests/utils_tests/test_http.py
index b435e33e44..d339e8a79c 100644
--- a/tests/utils_tests/test_http.py
+++ b/tests/utils_tests/test_http.py
@@ -248,3 +248,13 @@ class HttpDateProcessingTests(unittest.TestCase):
     def test_parsing_asctime(self):
         parsed = http.parse_http_date('Sun Nov  6 08:49:37 1994')
         self.assertEqual(datetime.utcfromtimestamp(parsed), datetime(1994, 11, 6, 8, 49, 37))
+
+
+class EscapeLeadingSlashesTests(unittest.TestCase):
+    def test(self):
+        tests = (
+            ('//example.com', '/%2Fexample.com'),
+            ('//', '/%2F'),
+        )
+        for url, expected in tests:
+            self.assertEqual(http.escape_leading_slashes(url), expected)