Fixed #23601 -- Ensured view exists in URLconf before importing it in admindocs.

django/contrib/admindocs/views.py

@@ -143,10 +143,11 @@ class ViewDetailView(BaseAdminDocsView):
 
     def get_context_data(self, **kwargs):
         view = self.kwargs['view']
-        mod, func = urlresolvers.get_mod_func(view)
-        try:
+        urlconf = urlresolvers.get_urlconf()
+        if urlresolvers.get_resolver(urlconf)._is_callback(view):
+            mod, func = urlresolvers.get_mod_func(view)
             view_func = getattr(import_module(mod), func)
-        except (ImportError, AttributeError):
+        else:
             raise Http404
         title, body, metadata = utils.parse_docstring(view_func.__doc__)
         if title:

django/core/urlresolvers.py

@@ -353,6 +353,11 @@ class RegexURLResolver(LocaleRegexProvider):
             self._populate()
         return self._app_dict[language_code]
 
+    def _is_callback(self, name):
+        if not self._populated:
+            self._populate()
+        return name in self._callback_strs
+
     def resolve(self, path):
         path = force_text(path)  # path may be a reverse_lazy object
         tried = []
@@ -430,7 +435,7 @@ class RegexURLResolver(LocaleRegexProvider):
 
         original_lookup = lookup_view
         try:
-            if lookup_view in self._callback_strs:
+            if self._is_callback(lookup_view):
                 lookup_view = get_callable(lookup_view, True)
         except (ImportError, AttributeError) as e:
             raise NoReverseMatch("Error importing '%s': %s." % (lookup_view, e))

docs/releases/1.8.txt

@@ -76,6 +76,14 @@ Minor features
   <django.contrib.admin.ModelAdmin.show_full_result_count>` to control whether
   or not the full count of objects should be displayed on a filtered admin page.
 
+:mod:`django.contrib.admindocs`
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+* The view to browse view details now checks if the view specified in the URL
+  exists in the URLconf. Previously it was possible to import arbitrary
+  packages from the Python path. This was not considered a security issue
+  because ``admindocs`` is only accessible to staff users.
+
 :mod:`django.contrib.auth`
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 

tests/admin_docs/tests.py

@@ -1,3 +1,4 @@
+import sys
 import unittest
 
 from django.conf import settings
@@ -84,6 +85,16 @@ class AdminDocViewTests(AdminDocsTestCase):
         # View docstring
         self.assertContains(response, 'Base view for admindocs views.')
 
+    def test_view_detail_illegal_import(self):
+        """
+        #23601 - Ensure the view exists in the URLconf.
+        """
+        response = self.client.get(
+            reverse('django-admindocs-views-detail',
+                    args=['urlpatterns_reverse.nonimported_module.view']))
+        self.assertEqual(response.status_code, 404)
+        self.assertNotIn("urlpatterns_reverse.nonimported_module", sys.modules)
+
     def test_model_index(self):
         response = self.client.get(reverse('django-admindocs-models-index'))
         self.assertContains(