diff options
Diffstat (limited to 'src/leap/soledad')
| -rw-r--r-- | src/leap/soledad/__init__.py | 100 |
1 files changed, 37 insertions, 63 deletions
diff --git a/src/leap/soledad/__init__.py b/src/leap/soledad/__init__.py index b051a80c..9824c5f6 100644 --- a/src/leap/soledad/__init__.py +++ b/src/leap/soledad/__init__.py @@ -54,7 +54,6 @@ from leap.common.keymanager.errors import DecryptionFailed from leap.soledad.backends import sqlcipher from leap.soledad.backends.leap_backend import ( LeapDocument, - DocumentNotEncrypted, LeapSyncTarget, ) @@ -96,22 +95,6 @@ class NotADirectory(Exception): # -# Helper functions -# - -def base64_encode(data): - """ - Return the base64 encoded version of C{data}. - - @return: The base64 encoded version of C{data}. - @rtype: str - """ - # binascii.b2a_base64 returns a new line character in the end of the - # string, so we strip that here. - return binascii.b2a_base64(data)[:-1] - - -# # Soledad: local encrypted storage and remote encrypted sync. # @@ -164,6 +147,12 @@ class Soledad(object): encryption. """ + IV_SEPARATOR = ":" + """ + A separator used for storing the encryption initial value prepended to the + ciphertext. + """ + UUID_KEY = 'uuid' STORAGE_SECRETS_KEY = 'storage_secrets' SECRET_KEY = 'secret' @@ -286,9 +275,7 @@ class Soledad(object): logger.info( 'Found cryptographic secrets in shared recovery ' 'database.') - self.import_recovery_document( - doc.content[self.SECRET_KEY], - passphrase=self._passphrase) + self.import_recovery_document(doc.content[self.SECRET_KEY]) else: # there are no secrets in server also, so generate a secret. logger.info( @@ -314,14 +301,12 @@ class Soledad(object): def _init_db(self): """ - Initialize the database for local storage. + Initialize the U1DB SQLCipher database for local storage. """ - # instantiate u1db - # TODO: verify if secret for sqlcipher should be the same as the - # one for symmetric encryption. self._db = sqlcipher.open( self._local_db_path, - self._get_storage_secret(), + # storage secret is binary but sqlcipher passphrase must be string + binascii.b2a_hex(self._get_storage_secret()), create=True, document_factory=LeapDocument, crypto=self._crypto) @@ -347,25 +332,28 @@ class Soledad(object): def _get_storage_secret(self): """ - Return the base64 encoding of the storage secret. + Return the storage secret. - Storage secret is first base64 encoded and then encrypted before being - stored. This message only decrypts the stored secret and returns the - base64 encoded version. + Storage secret is encrypted before being stored. This method decrypts + and returns the stored secret. - @return: The base64 encoding of the storage secret. + @return: The storage secret. @rtype: str """ - key = base64_encode( - scrypt.hash( - self._passphrase, - # the salt is also stored as base64 encoded string, so make - # direct use of this encoded version to derive the encryption - # key. - self._secrets[self._secret_id][self.KDF_SALT_KEY])) - return self._crypto.decrypt_sym( - self._secrets[self._secret_id][self.SECRET_KEY], - passphrase=key) + # calculate the encryption key + key = scrypt.hash( + self._passphrase, + # the salt is stored base64 encoded + binascii.a2b_base64( + self._secrets[self._secret_id][self.KDF_SALT_KEY]), + buflen=32, # we need a key with 256 bits (32 bytes). + ) + # recover the initial value and ciphertext + iv, ciphertext = self._secrets[self._secret_id][self.SECRET_KEY].split( + self.IV_SEPARATOR, 1) + iv = int(iv) + ciphertext = binascii.a2b_base64(ciphertext) + return self._crypto.decrypt_sym(ciphertext, key, iv=iv) def _set_secret_id(self, secret_id): """ @@ -408,11 +396,6 @@ class Soledad(object): # choose first secret if no secret_id was given if self._secret_id is None: self._set_secret_id(self._secrets.items()[0][0]) - # check secret is isncrypted - if not self._crypto.is_encrypted_sym( - self._secrets[self._secret_id][self.SECRET_KEY]): - raise DocumentNotEncrypted( - "File %s is not encrypted!" % self._secrets_path) def _has_secret(self): """ @@ -465,19 +448,20 @@ class Soledad(object): secret = os.urandom(self.STORAGE_SECRET_LENGTH) secret_id = sha256(secret).hexdigest() # generate random salt - base64_salt = base64_encode(os.urandom(self.SALT_LENGTH)) - key = scrypt.hash(self._passphrase, base64_salt) + salt = os.urandom(self.SALT_LENGTH) + # get a 256-bit key + key = scrypt.hash(self._passphrase, salt, buflen=32) + iv, ciphertext = self._crypto.encrypt_sym(secret, key) self._secrets[secret_id] = { # leap.common.keymanager.openpgp uses AES256 for symmetric # encryption. self.KDF_KEY: 'scrypt', # TODO: remove hard coded kdf - self.KDF_SALT_KEY: base64_salt, + self.KDF_SALT_KEY: binascii.b2a_base64(salt), self.KDF_LENGTH_KEY: len(key), self.CIPHER_KEY: 'aes256', # TODO: remove hard coded cipher self.LENGTH_KEY: len(secret), - self.SECRET_KEY: self._crypto.encrypt_sym( - base64_encode(secret), - base64_encode(key)), + self.SECRET_KEY: '%s%s%s' % ( + str(iv), self.IV_SEPARATOR, binascii.b2a_base64(ciphertext)), } self._store_secrets() events.signal( @@ -571,8 +555,7 @@ class Soledad(object): doc = LeapDocument(doc_id=self._uuid_hash()) # fill doc with encrypted secrets doc.content = { - self.SECRET_KEY: self.export_recovery_document( - self._passphrase) + self.SECRET_KEY: self.export_recovery_document() } # upload secrets to server events.signal( @@ -923,25 +906,16 @@ class Soledad(object): self.UUID_KEY: self._uuid, self.STORAGE_SECRETS_KEY: self._secrets, }) - if passphrase: - data = self._crypto.encrypt_sym(data, passphrase) return data - def import_recovery_document(self, data, passphrase=None): + def import_recovery_document(self, data): """ Import username, provider, private key and key for symmetric encryption from a recovery document. @param data: the recovery document json serialization @type data: str - @param passphrase: an optional passphrase for decrypting the document - @type passphrase: str """ - if passphrase and not self._crypto.is_encrypted_sym(data): - raise DocumentNotEncrypted("You provided a password but the " - "recovery document is not encrypted.") - if passphrase: - data = self._crypto.decrypt_sym(data, passphrase=passphrase) data = json.loads(data) # include new secrets in our secret pool. for secret_id, secret_data in data[self.STORAGE_SECRETS_KEY].items(): |