diff options
| -rw-r--r-- | client/changes/feature_6980_remove-mac-from-secrets-file | 1 | ||||
| -rw-r--r-- | client/src/leap/soledad/client/secrets.py | 71 |
2 files changed, 11 insertions, 61 deletions
diff --git a/client/changes/feature_6980_remove-mac-from-secrets-file b/client/changes/feature_6980_remove-mac-from-secrets-file new file mode 100644 index 00000000..6a424013 --- /dev/null +++ b/client/changes/feature_6980_remove-mac-from-secrets-file @@ -0,0 +1 @@ + o Remove MAC from secrets file. Closes #6980. diff --git a/client/src/leap/soledad/client/secrets.py b/client/src/leap/soledad/client/secrets.py index 57a1169a..97dbbaca 100644 --- a/client/src/leap/soledad/client/secrets.py +++ b/client/src/leap/soledad/client/secrets.py @@ -23,7 +23,6 @@ Soledad secrets handling. import os import scrypt -import hmac import logging import binascii import errno @@ -37,7 +36,6 @@ from leap.soledad.common import soledad_assert from leap.soledad.common import soledad_assert_type from leap.soledad.common import document from leap.soledad.common import errors -from leap.soledad.common import crypto from leap.soledad.client import events @@ -104,8 +102,8 @@ class SoledadSecrets(object): REMOTE_STORAGE_SECRET_LENGTH = 512 """ - The length, in bytes, of the secret used to derive an encryption key and a - MAC auth key for remote storage. + The length, in bytes, of the secret used to derive an encryption key for + remote storage. """ SALT_LENGTH = 64 @@ -275,7 +273,7 @@ class SoledadSecrets(object): content = None with open(self._secrets_path, 'r') as f: content = json.loads(f.read()) - _, mac, active_secret = self._import_recovery_document(content) + _, active_secret = self._import_recovery_document(content) # choose first secret if no secret_id was given if self._secret_id is None: if active_secret is None: @@ -291,7 +289,7 @@ class SoledadSecrets(object): self._secrets[self._secret_id] += new_piece enlarged = True # store and save in shared db if needed - if not mac or enlarged: + if enlarged: self._store_secrets() self._put_secrets_in_shared_db() @@ -311,9 +309,7 @@ class SoledadSecrets(object): logger.info( 'Found cryptographic secrets in shared recovery ' 'database.') - _, mac, active_secret = self._import_recovery_document(doc.content) - if mac is False: - self.put_secrets_in_shared_db() + _, active_secret = self._import_recovery_document(doc.content) self._store_secrets() # save new secrets in local file if self._secret_id is None: if active_secret is None: @@ -371,32 +367,20 @@ class SoledadSecrets(object): { 'storage_secrets': { '<storage_secret id>': { - 'kdf': 'scrypt', - 'kdf_salt': '<b64 repr of salt>' - 'kdf_length': <key length> 'cipher': 'aes256', 'length': <secret length>, 'secret': '<encrypted storage_secret>', }, }, 'active_secret': '<secret_id>', - 'kdf': 'scrypt', - 'kdf_salt': '<b64 repr of salt>', - 'kdf_length: <key length>, - '_mac_method': 'hmac', - '_mac': '<mac>' } Note that multiple storage secrets might be stored in one recovery - document. This method will also calculate a MAC of a string - representation of the secrets dictionary. + document. :return: The recovery document. :rtype: dict """ - # create salt and key for calculating MAC - salt = os.urandom(self.SALT_LENGTH) - key = scrypt.hash(self._passphrase_as_string(), salt, buflen=32) # encrypt secrets encrypted_secrets = {} for secret_id in self._secrets: @@ -406,14 +390,6 @@ class SoledadSecrets(object): data = { self.STORAGE_SECRETS_KEY: encrypted_secrets, self.ACTIVE_SECRET_KEY: self._secret_id, - self.KDF_KEY: self.KDF_SCRYPT, - self.KDF_SALT_KEY: binascii.b2a_base64(salt), - self.KDF_LENGTH_KEY: len(key), - crypto.MAC_METHOD_KEY: crypto.MacMethods.HMAC, - crypto.MAC_KEY: hmac.new( - key, - json.dumps(encrypted_secrets, sort_keys=True), - sha256).hexdigest(), } return data @@ -428,38 +404,11 @@ class SoledadSecrets(object): :param data: The recovery document. :type data: dict - :return: A tuple containing the number of imported secrets, whether - there was MAC information available for authenticating, and - the secret_id of the last active secret. - :rtype: (int, bool) + :return: A tuple containing the number of imported secrets and the + secret_id of the last active secret. + :rtype: (int, str) """ soledad_assert(self.STORAGE_SECRETS_KEY in data) - # check mac of the recovery document - mac = None - if crypto.MAC_KEY in data: - soledad_assert(data[crypto.MAC_KEY] is not None) - soledad_assert(crypto.MAC_METHOD_KEY in data) - soledad_assert(self.KDF_KEY in data) - soledad_assert(self.KDF_SALT_KEY in data) - soledad_assert(self.KDF_LENGTH_KEY in data) - if data[crypto.MAC_METHOD_KEY] == crypto.MacMethods.HMAC: - key = scrypt.hash( - self._passphrase_as_string(), - binascii.a2b_base64(data[self.KDF_SALT_KEY]), - buflen=32) - mac = hmac.new( - key, - json.dumps( - data[self.STORAGE_SECRETS_KEY], sort_keys=True), - sha256).hexdigest() - else: - raise crypto.UnknownMacMethodError('Unknown MAC method: %s.' % - data[crypto.MAC_METHOD_KEY]) - if mac != data[crypto.MAC_KEY]: - raise crypto.WrongMacError( - 'Could not authenticate recovery document\'s ' - 'contents.') - # include secrets in the secret pool. secret_count = 0 secrets = data[self.STORAGE_SECRETS_KEY].items() @@ -477,7 +426,7 @@ class SoledadSecrets(object): except SecretsException as e: logger.error("Failed to decrypt storage secret: %s" % str(e)) - return secret_count, mac, active_secret + return secret_count, active_secret def _get_secrets_from_shared_db(self): """ |