diff options
Diffstat (limited to 'client/src/leap/soledad')
| -rw-r--r-- | client/src/leap/soledad/client/_crypto.py | 114 |
1 files changed, 50 insertions, 64 deletions
diff --git a/client/src/leap/soledad/client/_crypto.py b/client/src/leap/soledad/client/_crypto.py index aaae7b92..f6a84b70 100644 --- a/client/src/leap/soledad/client/_crypto.py +++ b/client/src/leap/soledad/client/_crypto.py @@ -137,10 +137,9 @@ def encrypt_sym(data, key): encoded as base64. :rtype: (str, str) """ - encryptor = AESConsumer(key) + encryptor = AESWriter(key) encryptor.write(data) - encryptor.end() - ciphertext = encryptor.buffer.getvalue() + ciphertext = encryptor.end() return base64.b64encode(encryptor.iv), ciphertext @@ -160,10 +159,9 @@ def decrypt_sym(data, key, iv): :rtype: str """ _iv = base64.b64decode(str(iv)) - decryptor = AESConsumer(key, _iv, operation=AESConsumer.decrypt) + decryptor = AESWriter(key, _iv, encrypt=False) decryptor.write(data) - decryptor.end() - plaintext = decryptor.buffer.getvalue() + plaintext = decryptor.end() return plaintext @@ -196,12 +194,12 @@ class BlobEncryptor(object): mac_key = _get_mac_key_for_doc(doc_info.doc_id, secret) self._aes_fd = BytesIO() - _aes = AESConsumer(sym_key, _buffer=self._aes_fd) + _aes = AESWriter(sym_key, _buffer=self._aes_fd) self.__iv = _aes.iv self._hmac_writer = HMACWriter(mac_key) self._write_preamble() - self._crypter = PipeableWriter(_aes, self._hmac_writer) + self._crypter = VerifiedAESWriter(_aes, self._hmac_writer) @property def iv(self): @@ -274,9 +272,9 @@ class BlobDecryptor(object): self.result = result or BytesIO() sym_key = _get_sym_key_for_doc(doc_info.doc_id, secret) - _aes = AESConsumer(sym_key, iv, self.result, - operation=AESConsumer.decrypt) - self._decrypter = PipeableWriter(_aes, _hmac_writer, pipe=False) + _aes = AESWriter(sym_key, iv, self.result, + encrypt=False) + self._decrypter = VerifiedAESWriter(_aes, _hmac_writer, encrypt=False) self._producer = FileBodyProducer(ciphertext_fd, readSize=2**16) @@ -334,87 +332,75 @@ class BlobDecryptor(object): return d -class HMACWriter(object): +class GenericWriter(object): """ - A Twisted's Consumer implementation that takes an input file descriptor and - produces a HMAC-SHA512 Message Authentication Code. + A Twisted's Consumer implementation that can perform one opearation at the + written data and another at the end of the stream. """ implements(interfaces.IConsumer) - hashtype = 'sha512' - def __init__(self, key, result=None): - self._hmac = hmac.new(key, '', getattr(hashlib, self.hashtype)) - self.result = result or BytesIO('') + def __init__(self, operator, closer, result=None): + self.result = result or BytesIO() + self.operator, self.closer = operator, closer def write(self, data): - self._hmac.update(data) + out = self.operator(data) + if out: + self.result.write(out) + return out def end(self): - self.result.write(self._hmac.digest()) + self.result.write(self.closer()) return self.result.getvalue() -class PipeableWriter(object): +class HMACWriter(GenericWriter): """ - A Twisted's Consumer implementation that flows data into two writers. - Here we can combine AESEncryptor and HMACWriter. - It directs the resulting ciphertext into HMAC-SHA512 processing if - pipe=True or writes the ciphertext to both (fan out, which is the case when - decrypting). + A Twisted's Consumer implementation that takes an input file descriptor and + produces a HMAC-SHA512 Message Authentication Code. """ - implements(interfaces.IConsumer) - - def __init__(self, aes_writer, hmac_writer, pipe=True): - self.pipe = pipe - self.aes_writer = aes_writer - self.hmac_writer = hmac_writer - - def write(self, data): - enc_chunk = self.aes_writer.write(data) - if not self.pipe: - enc_chunk = data - self.hmac_writer.write(enc_chunk) + hashtype = 'sha512' - def end(self): - ciphertext = self.aes_writer.end() - content_hmac = self.hmac_writer.end() - return ciphertext, content_hmac + def __init__(self, key, result=None): + hmac_obj = hmac.new(key, '', getattr(hashlib, self.hashtype)) + GenericWriter.__init__(self, hmac_obj.update, hmac_obj.digest, result) -class AESConsumer(object): +class AESWriter(GenericWriter): """ A Twisted's Consumer implementation that takes an input file descriptor and applies AES-256 cipher in CTR mode. """ - implements(interfaces.IConsumer) - encrypt = 1 - decrypt = 2 - - def __init__(self, key, iv=None, _buffer=None, operation=encrypt): + def __init__(self, key, iv=None, _buffer=None, encrypt=True): if len(key) != 32: raise EncryptionDecryptionError('key is not 256 bits') self.iv = iv or os.urandom(16) - self.buffer = _buffer or BytesIO() - self.deferred = defer.Deferred() - self.done = False - cipher = _get_aes_ctr_cipher(key, self.iv) - if operation == self.encrypt: - self.operator = cipher.encryptor() - else: - self.operator = cipher.decryptor() + cipher = cipher.encryptor() if encrypt else cipher.decryptor() + GenericWriter.__init__(self, cipher.update, cipher.finalize, _buffer) + + +class VerifiedAESWriter(object): + """ + A Twisted's Consumer implementation that flows data into two writers. + Here we can combine AESEncryptor and HMACWriter. + It directs the resulting ciphertext into HMAC-SHA512 processing if + pipe=True or writes the ciphertext to both (fan out, which is the case when + decrypting). + """ + implements(interfaces.IConsumer) + + def __init__(self, aes_writer, hmac_writer, encrypt=True): + self.encrypt = encrypt + self.aes_writer = aes_writer + self.hmac_writer = hmac_writer def write(self, data): - consumed = self.operator.update(data) - self.buffer.write(consumed) - return consumed + enc_chunk = self.aes_writer.write(data) + self.hmac_writer.write(enc_chunk if self.encrypt else data) def end(self): - if not self.done: - self.buffer.write(self.operator.finalize()) - self.deferred.callback(self.buffer) - self.done = True - return self.buffer.getvalue() + return self.aes_writer.end(), self.hmac_writer.end() def is_symmetrically_encrypted(doc): |