| Index: reviewbot/third_party/google-api-python-client/oauth2client/xsrfutil.py
|
| ===================================================================
|
| --- reviewbot/third_party/google-api-python-client/oauth2client/xsrfutil.py (revision 0)
|
| +++ reviewbot/third_party/google-api-python-client/oauth2client/xsrfutil.py (revision 0)
|
| @@ -0,0 +1,113 @@
|
| +#!/usr/bin/python2.5
|
| +#
|
| +# Copyright 2010 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>',
|
| +]
|
| +
|
| +
|
| +import base64
|
| +import hmac
|
| +import os # for urandom
|
| +import time
|
| +
|
| +from oauth2client import util
|
| +
|
| +
|
| +# Delimiter character
|
| +DELIMITER = ':'
|
| +
|
| +# 1 hour in seconds
|
| +DEFAULT_TIMEOUT_SECS = 1*60*60
|
| +
|
| +@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))
|
| + digester.update(DELIMITER)
|
| + digester.update(action_id)
|
| + digester.update(DELIMITER)
|
| + digester.update(str(when))
|
| + digest = digester.digest()
|
| +
|
| + token = base64.urlsafe_b64encode('%s%s%d' % (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])
|
| + 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
|
|
|
| Property changes on: reviewbot/third_party/google-api-python-client/oauth2client/xsrfutil.py
|
| ___________________________________________________________________
|
| Added: svn:eol-style
|
| + LF
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|