207 lines
7.6 KiB
Python
207 lines
7.6 KiB
Python
# Copyright (c) 2013-2014 Rackspace, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import abc
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from Crypto.Cipher import AES
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from Crypto import Random
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from oslo.config import cfg
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from barbican.openstack.common.gettextutils import _
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CONF = cfg.CONF
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simple_crypto_plugin_group = cfg.OptGroup(name='simple_crypto_plugin',
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title="Simple Crypto Plugin Options")
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simple_crypto_plugin_opts = [
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cfg.StrOpt('kek',
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default=b'sixteen_byte_key',
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help=_('Key encryption key to be used by Simple Crypto Plugin'))
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]
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CONF.register_group(simple_crypto_plugin_group)
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CONF.register_opts(simple_crypto_plugin_opts, group=simple_crypto_plugin_group)
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class PluginSupportTypes(object):
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"""Class to hold the type enumeration that plugins may support."""
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ENCRYPT_DECRYPT = "ENCRYPT_DECRYPT"
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SYMMETRIC_KEY_GENERATION = "SYMMETRIC_KEY_GENERATION"
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# A list of symmetric algorithms that are used to determine type of key gen
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SYMMETRIC_ALGORITHMS = ['aes', 'des']
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class KEKMetaDTO(object):
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"""
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Data transfer object to support key encryption key (KEK) definition.
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Instances are passed into third-party plugins rather than passing in
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KekDatum instances directly. This provides a level of isolation from
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these third party systems and Barbican's data model.
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"""
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def __init__(self, kek_datum):
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"""
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kek_datum is typically a barbican.model.models.EncryptedDatum instance.
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"""
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self.kek_label = kek_datum.kek_label
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self.plugin_name = kek_datum.plugin_name
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self.algorithm = kek_datum.algorithm
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self.bit_length = kek_datum.bit_length
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self.mode = kek_datum.mode
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self.plugin_meta = kek_datum.plugin_meta
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def indicate_bind_completed(kek_meta_dto, kek_datum):
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"""
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Updates the supplied kek_datum instance per the contents of the supplied
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kek_meta_dto instance. This function is typically used once plugins have
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had a chance to bind kek_meta_dto to their crypto systems.
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:param kek_meta_dto:
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:param kek_datum:
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:return: None
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"""
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kek_datum.bind_completed = True
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kek_datum.algorithm = kek_meta_dto.algorithm
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kek_datum.bit_length = kek_meta_dto.bit_length
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kek_datum.mode = kek_meta_dto.mode
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kek_datum.plugin_meta = kek_meta_dto.plugin_meta
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class CryptoPluginBase(object):
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"""Base class for Crypto plugins."""
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__metaclass__ = abc.ABCMeta
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@abc.abstractmethod
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def encrypt(self, unencrypted, kek_meta_dto, keystone_id):
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"""Encrypt unencrypted data in the context of the provided tenant.
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:param unencrypted: byte data to be encrypted.
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:param kek_meta_dto: Key encryption key metadata to use for encryption.
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:param keystone_id: keystone_id associated with the unencrypted data.
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:returns: encrypted data and kek_meta_extended, the former the
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resultant cypher text, the latter being optional per-secret metadata
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needed to decrypt (over and above the per-tenant metadata managed
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outside of the plugins)
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"""
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@abc.abstractmethod
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def decrypt(self, encrypted, kek_meta_dto, kek_meta_extended, keystone_id):
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"""Decrypt encrypted_datum in the context of the provided tenant.
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:param encrypted: cyphertext to be decrypted.
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:param kek_meta_dto: Key encryption key metadata to use for decryption
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:param kek_meta_extended: Optional per-secret KEK metadata to use for
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decryption.
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:param keystone_id: keystone_id associated with the encrypted datum.
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:returns: str -- unencrypted byte data
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"""
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@abc.abstractmethod
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def bind_kek_metadata(self, kek_meta_dto):
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"""
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Bind a key encryption key (KEK) metadata to the sub-system
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handling encryption/decryption, updating information about the
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key encryption key (KEK) metadata in the supplied 'kek_metadata'
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data-transfer-object instance, and then returning this instance.
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This method is invoked prior to the encrypt() method above.
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Implementors should fill out the supplied 'kek_meta_dto' instance
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(an instance of KEKMetadata above) as needed to completely describe
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the kek metadata and to complete the binding process. Barbican will
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persist the contents of this instance once this method returns.
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:param kek_meta_dto: Key encryption key metadata to bind, with the
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'kek_label' attribute guaranteed to be unique, and the
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and 'plugin_name' attribute already configured.
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:returns: kek_meta_dto: Returns the specified DTO, after
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modifications.
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"""
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@abc.abstractmethod
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def create(self, bit_length, type_enum, algorithm=None, mode=None):
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"""Create a new key."""
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@abc.abstractmethod
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def supports(self, type_enum, algorithm=None, mode=None):
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"""Used to determine if the plugin supports the requested operation.
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:param type_enum: Enumeration from PluginSupportsType class
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:param algorithm: String algorithm name if needed
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"""
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class SimpleCryptoPlugin(CryptoPluginBase):
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"""Insecure implementation of the crypto plugin."""
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def __init__(self, conf=CONF):
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self.kek = conf.simple_crypto_plugin.kek
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self.block_size = AES.block_size
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def _pad(self, unencrypted):
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"""Adds padding to unencrypted byte string."""
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pad_length = self.block_size - (
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len(unencrypted) % self.block_size
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)
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return unencrypted + (chr(pad_length) * pad_length)
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def _strip_pad(self, unencrypted):
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pad_length = ord(unencrypted[-1:])
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unpadded = unencrypted[:-pad_length]
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return unpadded
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def encrypt(self, unencrypted, kek_meta_dto, keystone_id):
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if not isinstance(unencrypted, str):
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raise ValueError('Unencrypted data must be a byte type, '
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'but was {0}'.format(type(unencrypted)))
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padded_data = self._pad(unencrypted)
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iv = Random.get_random_bytes(self.block_size)
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encryptor = AES.new(self.kek, AES.MODE_CBC, iv)
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cyphertext = iv + encryptor.encrypt(padded_data)
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return cyphertext, None
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def decrypt(self, encrypted, kek_meta_dto, kek_meta_extended, keystone_id):
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iv = encrypted[:self.block_size]
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cypher_text = encrypted[self.block_size:]
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decryptor = AES.new(self.kek, AES.MODE_CBC, iv)
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padded_secret = decryptor.decrypt(cypher_text)
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return self._strip_pad(padded_secret)
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def bind_kek_metadata(self, kek_meta_dto):
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kek_meta_dto.algorithm = 'aes'
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kek_meta_dto.bit_length = 128
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kek_meta_dto.mode = 'cbc'
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kek_meta_dto.plugin_meta = None
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return kek_meta_dto
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def create(self, bit_length, type_enum, algorithm=None, mode=None):
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byte_length = bit_length / 8
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return Random.get_random_bytes(byte_length)
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def supports(self, type_enum, algorithm=None, mode=None):
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if type_enum == PluginSupportTypes.ENCRYPT_DECRYPT:
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return True
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elif type_enum == PluginSupportTypes.SYMMETRIC_KEY_GENERATION:
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return True
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else:
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return False
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