# keystone.credential.providers.fernet.core

# Source code for keystone.credential.providers.fernet.core

    # Licensed under the Apache License, Version 2.0 (the "License"); you may
    # not use this file except in compliance with the License. You may obtain
    # a copy of the License at
    #
    #      http://www.apache.org/licenses/LICENSE-2.0
    #
    # Unless required by applicable law or agreed to in writing, software
    # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
    # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
    # License for the specific language governing permissions and limitations
    # under the License.

    import hashlib

    from cryptography import fernet
    from oslo_log import log

    from keystone.common import fernet_utils
    import keystone.conf
    from keystone.credential.providers import core
    from keystone import exception
    from keystone.i18n import _

    CONF = keystone.conf.CONF
    LOG = log.getLogger(__name__)

    # NOTE(lbragstad): Credential key rotation operates slightly different than
    # token key rotation. Each credential holds a hash of the key that encrypted
    # it. This is important for credential key rotation because it helps us make
    # sure we don't over-rotate credential keys. During a rotation of credential
    # keys, if any credential has not been re-encrypted with the current primary
    # key, we can abandon the key rotation until all credentials have been migrated
    # to the new primary key. If we don't take this step, it is possible that we
    # could remove a key used to encrypt credentials, leaving them unrecoverable.
    # This also means that we don't need to expose a `[credential] max_active_keys`
    # option through configuration. Instead we will use a global variable and share
    # that across all places that need to use FernetUtils for credential
    # encryption.
    MAX_ACTIVE_KEYS = 3

    def get_multi_fernet_keys():
        key_utils = fernet_utils.FernetUtils(
            CONF.credential.key_repository, MAX_ACTIVE_KEYS, 'credential'
        )
        keys = key_utils.load_keys(use_null_key=True)

        fernet_keys = [fernet.Fernet(key) for key in keys]
        crypto = fernet.MultiFernet(fernet_keys)

        return crypto, keys

    def primary_key_hash(keys):
        """Calculate a hash of the primary key used for encryption."""
        if isinstance(keys[0], str):
            keys[0] = keys[0].encode('utf-8')
        # NOTE(lhinds) This is marked as #nosec since bandit will see SHA1 which
        # is marked as insecure. However, this hash function is used alongside
        # encrypted blobs to implement HMAC-SHA1, which is currently not insecure
        # but will still trigger when scanned by bandit.
        return hashlib.sha1(keys[0]).hexdigest()  # nosec

    class Provider(core.Provider):

        def encrypt(self, credential):
            """Attempt to encrypt a plaintext credential.

            :param credential: a plaintext representation of a credential
            :returns: an encrypted credential
            """
            crypto, keys = get_multi_fernet_keys()

            if keys[0] == fernet_utils.NULL_KEY:
                LOG.warning(
                    'Encrypting credentials with the null key. Please properly '
                    'encrypt credentials using `keystone-manage credential_setup`,'
                    ' `keystone-manage credential_migrate`, and `keystone-manage '
                    'credential_rotate`'
                )

            try:
                return (
                    crypto.encrypt(credential.encode('utf-8')),
                    primary_key_hash(keys),
                )
            except (TypeError, ValueError) as e:
                msg = f'Credential could not be encrypted: {str(e)}'
                tr_msg = _('Credential could not be encrypted: %s') % str(e)
                LOG.error(msg)
                raise exception.CredentialEncryptionError(tr_msg)

        def decrypt(self, credential):
            """Attempt to decrypt a credential.

            :param credential: an encrypted credential string
            :returns: a decrypted credential
            """
            key_utils = fernet_utils.FernetUtils(
                CONF.credential.key_repository, MAX_ACTIVE_KEYS, 'credential'
            )
            keys = key_utils.load_keys(use_null_key=True)
            fernet_keys = [fernet.Fernet(key) for key in keys]
            crypto = fernet.MultiFernet(fernet_keys)

            try:
                if isinstance(credential, str):
                    credential = credential.encode('utf-8')
                return crypto.decrypt(credential).decode('utf-8')
            except (fernet.InvalidToken, TypeError, ValueError):
                msg = (
                    'Credential could not be decrypted. Please contact the '
                    'administrator'
                )
                tr_msg = _(
                    'Credential could not be decrypted. Please contact the '
                    'administrator'
                )
                LOG.error(msg)
                raise exception.CredentialEncryptionError(tr_msg)

this page last updated: 2026-08-17 12:45:24

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