make version of ts_mon compatible with appengine

appengine/chromium_build_logs/third_party/oauth2client/xsrfutil.py

-#!/usr/bin/python2.5
 #
-# Copyright 2010 the Melange authors.
+# Copyright 2014 the Melange authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #   http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
 """Helper methods for creating & verifying XSRF tokens."""
 
 __authors__ = [
-  '"Doug Coker" <dcoker@google.com>',
-  '"Joe Gregorio" <jcgregorio@google.com>',
+    '"Doug Coker" <dcoker@google.com>',
+    '"Joe Gregorio" <jcgregorio@google.com>',
 ]
 
 
 import base64
 import hmac
-import os  # for urandom
 import time
 
+import six
 from oauth2client import util
 
 
 # Delimiter character
-DELIMITER = ':'
+DELIMITER = b':'
+
 
 # 1 hour in seconds
 DEFAULT_TIMEOUT_SECS = 1*60*60
 
+
+def _force_bytes(s):
+    if isinstance(s, bytes):
+        return s
+    s = str(s)
+    if isinstance(s, six.text_type):
+        return s.encode('utf-8')
+    return s
+
+
 @util.positional(2)
 def generate_token(key, user_id, action_id="", when=None):
   """Generates a URL-safe token for the given user, action, time tuple.
 
   Args:
     key: secret key to use.
     user_id: the user ID of the authenticated user.
     action_id: a string identifier of the action they requested
       authorization for.
     when: the time in seconds since the epoch at which the user was
       authorized for this action. If not set the current time is used.
 
   Returns:
     A string XSRF protection token.
   """
-  when = when or int(time.time())
-  digester = hmac.new(key)
-  digester.update(str(user_id))
+  when = _force_bytes(when or int(time.time()))
+  digester = hmac.new(_force_bytes(key))
+  digester.update(_force_bytes(user_id))
   digester.update(DELIMITER)
-  digester.update(action_id)
+  digester.update(_force_bytes(action_id))
   digester.update(DELIMITER)
-  digester.update(str(when))
+  digester.update(when)
   digest = digester.digest()
 
-  token = base64.urlsafe_b64encode('%s%s%d' % (digest,
-                                               DELIMITER,
-                                               when))
+  token = base64.urlsafe_b64encode(digest + DELIMITER + when)
   return token
 
 
 @util.positional(3)
 def validate_token(key, token, user_id, action_id="", current_time=None):
   """Validates that the given token authorizes the user for the action.
 
   Tokens are invalid if the time of issue is too old or if the token
   does not match what generateToken outputs (i.e. the token was forged).
 
   Args:
     key: secret key to use.
     token: a string of the token generated by generateToken.
     user_id: the user ID of the authenticated user.
     action_id: a string identifier of the action they requested
       authorization for.
 
   Returns:
     A boolean - True if the user is authorized for the action, False
     otherwise.
   """
   if not token:
     return False
   try:
-    decoded = base64.urlsafe_b64decode(str(token))
-    token_time = long(decoded.split(DELIMITER)[-1])
+    decoded = base64.urlsafe_b64decode(token)
+    token_time = int(decoded.split(DELIMITER)[-1])
   except (TypeError, ValueError):
     return False
   if current_time is None:
     current_time = time.time()
   # If the token is too old it's not valid.
   if current_time - token_time > DEFAULT_TIMEOUT_SECS:
     return False
 
   # The given token should match the generated one with the same time.
   expected_token = generate_token(key, user_id, action_id=action_id,
                                   when=token_time)
   if len(token) != len(expected_token):
     return False
 
   # Perform constant time comparison to avoid timing attacks
   different = 0
-  for x, y in zip(token, expected_token):
-    different |= ord(x) ^ ord(y)
-  if different:
-    return False
-
-  return True
+  for x, y in zip(bytearray(token), bytearray(expected_token)):
+    different |= x ^ y
+  return not different