diff options
| -rw-r--r-- | client/src/leap/soledad/client/_crypto.py | 30 | ||||
| -rw-r--r-- | testing/tests/client/test_crypto.py | 40 |
2 files changed, 54 insertions, 16 deletions
diff --git a/client/src/leap/soledad/client/_crypto.py b/client/src/leap/soledad/client/_crypto.py index 9f403cc9..c4c6d336 100644 --- a/client/src/leap/soledad/client/_crypto.py +++ b/client/src/leap/soledad/client/_crypto.py @@ -49,7 +49,8 @@ SECRET_LENGTH = 64 CRYPTO_BACKEND = MultiBackend([OpenSSLBackend()]) -PACMAN = struct.Struct('2sbbQ16s255p255p') +PACMAN = struct.Struct('2sbbQ16s255p255pQ') +LEGACY_PACMAN = struct.Struct('2sbbQ16s255p255p') BLOB_SIGNATURE_MAGIC = '\x13\x37' @@ -188,10 +189,13 @@ class BlobEncryptor(object): self.doc_id = doc_info.doc_id self.rev = doc_info.rev self._content_fd = content_fd + content_fd.seek(0, os.SEEK_END) + self._content_size = content_fd.tell() + content_fd.seek(0) self._producer = FileBodyProducer(content_fd, readSize=2**16) - sym_key = _get_sym_key_for_doc(doc_info.doc_id, secret) - self._aes = AESWriter(sym_key) + self.sym_key = _get_sym_key_for_doc(doc_info.doc_id, secret) + self._aes = AESWriter(self.sym_key) self._aes.authenticate(self._encode_preamble()) @property @@ -224,7 +228,8 @@ class BlobEncryptor(object): current_time, self.iv, str(self.doc_id), - str(self.rev)) + str(self.rev), + self._content_size) def _end_crypto_stream(self): preamble, encrypted = self._aes.end() @@ -271,14 +276,17 @@ class BlobDecryptor(object): raise InvalidBlob ciphertext_fd.close() - if len(preamble) != PACMAN.size: - raise InvalidBlob - try: - unpacked_data = PACMAN.unpack(preamble) - magic, sch, meth, ts, iv, doc_id, rev = unpacked_data - except struct.error: - raise InvalidBlob + if len(preamble) == LEGACY_PACMAN.size: + unpacked_data = LEGACY_PACMAN.unpack(preamble) + magic, sch, meth, ts, iv, doc_id, rev = unpacked_data + elif len(preamble) == PACMAN.size: + unpacked_data = PACMAN.unpack(preamble) + magic, sch, meth, ts, iv, doc_id, rev, doc_size = unpacked_data + else: + raise InvalidBlob("Unexpected preamble size %d", len(preamble)) + except struct.error, e: + raise InvalidBlob(e) if magic != BLOB_SIGNATURE_MAGIC: raise InvalidBlob diff --git a/testing/tests/client/test_crypto.py b/testing/tests/client/test_crypto.py index 852448e0..2d4d827b 100644 --- a/testing/tests/client/test_crypto.py +++ b/testing/tests/client/test_crypto.py @@ -110,7 +110,7 @@ class BlobTestCase(unittest.TestCase): assert len(preamble) == _crypto.PACMAN.size unpacked_data = _crypto.PACMAN.unpack(preamble) - magic, sch, meth, ts, iv, doc_id, rev = unpacked_data + magic, sch, meth, ts, iv, doc_id, rev, _ = unpacked_data assert magic == _crypto.BLOB_SIGNATURE_MAGIC assert sch == 1 assert meth == _crypto.ENC_METHOD.aes_256_gcm @@ -241,9 +241,9 @@ class PreambleTestCase(unittest.TestCase): rev = '397932e0c77f45fcb7c3732930e7e9b2:1' def setUp(self): - inf = BytesIO(snowden1) + self.cleartext = BytesIO(snowden1) self.blob = _crypto.BlobEncryptor( - self.doc_info, inf, + self.doc_info, self.cleartext, secret='A' * 96) def test_preamble_starts_with_magic_signature(self): @@ -261,15 +261,45 @@ class PreambleTestCase(unittest.TestCase): def test_preamble_has_document_sync_metadata(self): preamble = self.blob._encode_preamble() unpacked = _crypto.PACMAN.unpack(preamble) - doc_id, doc_rev = unpacked[5:] + doc_id, doc_rev = unpacked[5:7] assert doc_id == self.doc_info.doc_id assert doc_rev == self.doc_info.rev + def test_preamble_has_document_size(self): + preamble = self.blob._encode_preamble() + unpacked = _crypto.PACMAN.unpack(preamble) + size = unpacked[7] + assert size == len(snowden1) -def _aes_encrypt(key, iv, data): + @defer.inlineCallbacks + def test_preamble_can_come_without_size(self): + # XXX: This test case is here only to test backwards compatibility! + preamble = self.blob._encode_preamble() + # repack preamble using legacy format, without doc size + unpacked = _crypto.PACMAN.unpack(preamble) + preamble_without_size = _crypto.LEGACY_PACMAN.pack(*unpacked[0:7]) + # encrypt it manually for custom tag + ciphertext, tag = _aes_encrypt(self.blob.sym_key, self.blob.iv, + self.cleartext.getvalue(), + aead=preamble_without_size) + ciphertext = ciphertext + tag + # encode it + ciphertext = base64.urlsafe_b64encode(ciphertext) + preamble_without_size = base64.urlsafe_b64encode(preamble_without_size) + # decrypt it + ciphertext = preamble_without_size + ' ' + ciphertext + cleartext = yield _crypto.BlobDecryptor( + self.doc_info, BytesIO(ciphertext), + secret='A' * 96).decrypt() + assert cleartext == self.cleartext.getvalue() + + +def _aes_encrypt(key, iv, data, aead=''): backend = default_backend() cipher = Cipher(algorithms.AES(key), modes.GCM(iv), backend=backend) encryptor = cipher.encryptor() + if aead: + encryptor.authenticate_additional_data(aead) return encryptor.update(data) + encryptor.finalize(), encryptor.tag |