# -*- coding: utf-8 -*- # Copyright (C) 2014-2017 RhodeCode GmbH # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU Affero General Public License, version 3 # (only), as published by the Free Software Foundation. # # This program 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 Affero General Public License # along with this program. If not, see <http://www.gnu.org/licenses/>. # # This program is dual-licensed. If you wish to learn more about the # RhodeCode Enterprise Edition, including its added features, Support services, # and proprietary license terms, please see https://rhodecode.com/licenses/ """ Generic encryption library for RhodeCode """ import base64 from Crypto.Cipher import AES from Crypto import Random from Crypto.Hash import HMAC, SHA256 from rhodecode.lib.utils2 import safe_str class SignatureVerificationError(Exception): pass class InvalidDecryptedValue(str): def __new__(cls, content): """ This will generate something like this:: <InvalidDecryptedValue(QkWusFgLJXR6m42v...)> And represent a safe indicator that encryption key is broken """ content = '<{}({}...)>'.format(cls.__name__, content[:16]) return str.__new__(cls, content) class AESCipher(object): def __init__(self, key, hmac=False, strict_verification=True): if not key: raise ValueError('passed key variable is empty') self.strict_verification = strict_verification self.block_size = 32 self.hmac_size = 32 self.hmac = hmac self.key = SHA256.new(safe_str(key)).digest() self.hmac_key = SHA256.new(self.key).digest() def verify_hmac_signature(self, raw_data): org_hmac_signature = raw_data[-self.hmac_size:] data_without_sig = raw_data[:-self.hmac_size] recomputed_hmac = HMAC.new( self.hmac_key, data_without_sig, digestmod=SHA256).digest() return org_hmac_signature == recomputed_hmac def encrypt(self, raw): raw = self._pad(raw) iv = Random.new().read(AES.block_size) cipher = AES.new(self.key, AES.MODE_CBC, iv) enc_value = cipher.encrypt(raw) hmac_signature = '' if self.hmac: # compute hmac+sha256 on iv + enc text, we use # encrypt then mac method to create the signature hmac_signature = HMAC.new( self.hmac_key, iv + enc_value, digestmod=SHA256).digest() return base64.b64encode(iv + enc_value + hmac_signature) def decrypt(self, enc): enc_org = enc enc = base64.b64decode(enc) if self.hmac and len(enc) > self.hmac_size: if self.verify_hmac_signature(enc): # cut off the HMAC verification digest enc = enc[:-self.hmac_size] else: if self.strict_verification: raise SignatureVerificationError( "Encryption signature verification failed. " "Please check your secret key, and/or encrypted value. " "Secret key is stored as " "`rhodecode.encrypted_values.secret` or " "`beaker.session.secret` inside .ini file") return InvalidDecryptedValue(enc_org) iv = enc[:AES.block_size] cipher = AES.new(self.key, AES.MODE_CBC, iv) return self._unpad(cipher.decrypt(enc[AES.block_size:])) def _pad(self, s): return (s + (self.block_size - len(s) % self.block_size) * chr(self.block_size - len(s) % self.block_size)) @staticmethod def _unpad(s): return s[:-ord(s[len(s)-1:])]