diff -r 27971a13089f -r 2e0b0af889be thirdparty/google_appengine/lib/django/django/core/servers/basehttp.py
--- a/thirdparty/google_appengine/lib/django/django/core/servers/basehttp.py	Sat Sep 05 14:04:24 2009 +0200
+++ b/thirdparty/google_appengine/lib/django/django/core/servers/basehttp.py	Sun Sep 06 23:31:53 2009 +0200
@@ -11,6 +11,8 @@
 from types import ListType, StringType
 import os, re, sys, time, urllib
 
+from django.utils._os import safe_join
+
 __version__ = "0.1"
 __all__ = ['WSGIServer','WSGIRequestHandler','demo_app']
 
@@ -599,11 +601,25 @@
         self.application = application
         if not media_dir:
             import django
-            self.media_dir = django.__path__[0] + '/contrib/admin/media'
+            self.media_dir = \
+                os.path.join(django.__path__[0], 'contrib', 'admin', 'media')
         else:
             self.media_dir = media_dir
         self.media_url = settings.ADMIN_MEDIA_PREFIX
 
+    def file_path(self, url):
+        """
+        Returns the path to the media file on disk for the given URL.
+
+        The passed URL is assumed to begin with ADMIN_MEDIA_PREFIX.  If the
+        resultant file path is outside the media directory, then a ValueError
+        is raised.
+        """
+        # Remove ADMIN_MEDIA_PREFIX.
+        relative_url = url[len(self.media_url):]
+        relative_path = urllib.url2pathname(relative_url)
+        return safe_join(self.media_dir, relative_path)
+
     def __call__(self, environ, start_response):
         import os.path
 
@@ -614,19 +630,25 @@
             return self.application(environ, start_response)
 
         # Find the admin file and serve it up, if it exists and is readable.
-        relative_url = environ['PATH_INFO'][len(self.media_url):]
-        file_path = os.path.join(self.media_dir, relative_url)
+        try:
+            file_path = self.file_path(environ['PATH_INFO'])
+        except ValueError: # Resulting file path was not valid.
+            status = '404 NOT FOUND'
+            headers = {'Content-type': 'text/plain'}
+            output = ['Page not found: %s' % environ['PATH_INFO']]
+            start_response(status, headers.items())
+            return output
         if not os.path.exists(file_path):
             status = '404 NOT FOUND'
             headers = {'Content-type': 'text/plain'}
-            output = ['Page not found: %s' % file_path]
+            output = ['Page not found: %s' % environ['PATH_INFO']]
         else:
             try:
                 fp = open(file_path, 'rb')
             except IOError:
                 status = '401 UNAUTHORIZED'
                 headers = {'Content-type': 'text/plain'}
-                output = ['Permission denied: %s' % file_path]
+                output = ['Permission denied: %s' % environ['PATH_INFO']]
             else:
                 status = '200 OK'
                 headers = {}