Description: Fix directory-traversal vulnerability on Windows
Origin: upstream, http://code.djangoproject.com/changeset/15468
Bug: http://www.djangoproject.com/weblog/2011/feb/08/security/

Index: Django/django/contrib/sessions/tests.py
===================================================================
--- Django/django/contrib/sessions/tests.py	(revision 9934)
+++ Django/django/contrib/sessions/tests.py	(revision 15468)
@@ -130,4 +130,15 @@
 >>> file_session.save()
 
+# Ensure we don't allow directory traversal
+>>> FileSession("a/b/c").load()
+Traceback (innermost last):
+    ...
+SuspiciousOperation: Invalid characters in session key
+
+>>> FileSession("a\\b\\c").load()
+Traceback (innermost last):
+    ...
+SuspiciousOperation: Invalid characters in session key
+
 # Make sure the file backend checks for a good storage dir
 >>> settings.SESSION_FILE_PATH = "/if/this/directory/exists/you/have/a/weird/computer"
Index: Django/django/contrib/sessions/backends/file.py
===================================================================
--- Django/django/contrib/sessions/backends/file.py	(revision 8812)
+++ Django/django/contrib/sessions/backends/file.py	(revision 15468)
@@ -27,4 +27,6 @@
         super(SessionStore, self).__init__(session_key)
 
+    VALID_KEY_CHARS = set("abcdef0123456789")
+
     def _key_to_file(self, session_key=None):
         """
@@ -37,7 +39,7 @@
         # should always be md5s, so they should never contain directory
         # components.
-        if os.path.sep in session_key:
+        if not set(session_key).issubset(self.VALID_KEY_CHARS):
             raise SuspiciousOperation(
-                "Invalid characters (directory components) in session key")
+                "Invalid characters in session key")
 
         return os.path.join(self.storage_path, self.file_prefix + session_key)