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#!/usr/bin/env python
# coding: utf-8
# This file is part of Adblock Plus <http://adblockplus.org/>,
# Copyright (C) 2006-2014 Eyeo GmbH
#
# Adblock Plus is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 3 as
# published by the Free Software Foundation.
#
# Adblock Plus is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Adblock Plus. If not, see <http://www.gnu.org/licenses/>.
#############################################################################
# This is a reference script to validate the checksum in downloadable #
# subscription. This performs the same validation as Adblock Plus when it #
# downloads the subscription. #
# #
# To validate a subscription file, run the script like this: #
# #
# python validateChecksum.py < subscription.txt #
# #
# Note: your subscription file should be saved in UTF-8 encoding, otherwise #
# the validation will fail. #
# #
#############################################################################
import sys, re, codecs, hashlib, base64
checksumRegexp = re.compile(r'^\s*!\s*checksum[\s\-:]+([\w\+\/=]+).*\n', re.I | re.M)
def validate(data):
checksum = extractChecksum(data)
if not checksum:
raise Exception('Data doesn\'t contain a checksum, nothing to validate')
expectedChecksum = calculateChecksum(data)
if checksum == expectedChecksum:
print 'Checksum is valid'
else:
print 'Wrong checksum: found %s, expected %s' % (checksum, expectedChecksum)
def extractChecksum(data):
match = re.search(checksumRegexp, data)
return match.group(1) if match else None
def calculateChecksum(data):
md5 = hashlib.md5()
md5.update(normalize(data).encode('utf-8'))
return base64.b64encode(md5.digest()).rstrip('=')
def normalize(data):
data = re.sub(r'\r', '', data)
data = re.sub(r'\n+', '\n', data)
data = re.sub(checksumRegexp, '', data)
return data
def readStream(stream):
reader = codecs.getreader('utf8')(stream)
try:
return reader.read()
except Exception, e:
raise Exception('Failed reading data, most likely not encoded as UTF-8:\n%s' % e)
if __name__ == '__main__':
validate(readStream(sys.stdin))
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