349 lines
14 KiB
Python
349 lines
14 KiB
Python
# 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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import six
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from barbican.common import exception
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from barbican import i18n as u
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class CryptoPluginNotFound(exception.BarbicanException):
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"""Raised when no plugins are installed."""
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message = u._("Crypto plugin not found.")
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class CryptoKEKBindingException(exception.BarbicanException):
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"""Raised when the bind_kek_metadata method from a plugin returns None."""
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def __init__(self, plugin_name=u._('Unknown')):
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super(CryptoKEKBindingException, self).__init__(
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u._('Failed to bind kek metadata for '
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'plugin: {name}').format(name=plugin_name)
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)
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self.plugin_name = plugin_name
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class CryptoPrivateKeyFailureException(exception.BarbicanException):
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"""Raised when could not generate private key."""
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def __init__(self):
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super(CryptoPrivateKeyFailureException, self).__init__(
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u._('Could not generate private key')
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)
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# TODO(john-wood-w) Need to harmonize these lower-level constants with the
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# higher level constants in secret_store.py.
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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', '3des', 'hmacsha1',
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'hmacsha256', 'hmacsha384', 'hmacsha512']
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SYMMETRIC_KEY_LENGTHS = [64, 128, 192, 256]
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ASYMMETRIC_KEY_GENERATION = "ASYMMETRIC_KEY_GENERATION"
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ASYMMETRIC_ALGORITHMS = ['rsa', 'dsa']
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ASYMMETRIC_KEY_LENGTHS = [1024, 2048, 4096]
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class KEKMetaDTO(object):
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"""Key Encryption Key Meta DTO
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Key Encryption Keys (KEKs) in Barbican are intended to represent a
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distinct key that is used to perform encryption on secrets for a particular
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project.
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``KEKMetaDTO`` objects are provided to cryptographic backends by Barbican
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to allow plugins to persist metadata related to the project's KEK.
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For example, a plugin that interfaces with a Hardware Security Module (HSM)
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may want to use a different encryption key for each project. Such a plugin
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could use the ``KEKMetaDTO`` object to save the key ID used for that
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project. Barbican will persist the KEK metadata and ensure that it is
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provided to the plugin every time a request from that same project is
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processed.
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.. attribute:: plugin_name
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String attribute used by Barbican to identify the plugin that is bound
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to the KEK metadata. Plugins should not change this attribute.
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.. attribute:: kek_label
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String attribute used to label the project's KEK by the plugin.
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The value of this attribute should be meaningful to the plugin.
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Barbican does not use this value.
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.. attribute:: algorithm
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String attribute used to identify the encryption algorithm used by the
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plugin. e.g. "AES", "3DES", etc. This value should be meaningful to
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the plugin. Barbican does not use this value.
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.. attribute:: mode
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String attribute used to identify the algorithm mode used by the
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plugin. e.g. "CBC", "GCM", etc. This value should be meaningful to
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the plugin. Barbican does not use this value.
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.. attribute:: bit_length
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Integer attribute used to identify the bit length of the KEK by the
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plugin. This value should be meaningful to the plugin. Barbican does
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not use this value.
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.. attribute:: plugin_meta
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String attribute used to persist any additional metadata that does not
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fit in any other attribute. The value of this attribute is defined by
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the plugin. It could be used to store external system references, such
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as Key IDs in an HSM, URIs to an external service, or any other data
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that the plugin deems necessary to persist. Because this is just a
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plain text field, a plug in may even choose to persist data such as key
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value pairs in a JSON object.
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"""
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def __init__(self, kek_datum):
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"""Plugins should not have to create their own instance of this class.
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kek_datum is typically a barbican.model.models.KEKDatum 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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class GenerateDTO(object):
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"""Secret Generation DTO
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Data Transfer Object used to pass all the necessary data for the plugin
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to generate a secret on behalf of the user.
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.. attribute:: generation_type
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String attribute used to identify the type of secret that should be
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generated. This will be either ``"symmetric"`` or ``"asymmetric"``.
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.. attribute:: algorithm
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String attribute used to specify what type of algorithm the secret will
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be used for. e.g. ``"AES"`` for a ``"symmetric"`` type, or ``"RSA"``
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for ``"asymmetric"``.
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.. attribute:: mode
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String attribute used to specify what algorithm mode the secret will be
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used for. e.g. ``"CBC"`` for ``"AES"`` algorithm.
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.. attribute:: bit_length
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Integer attribute used to specify the bit length of the secret. For
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example, this attribute could specify the key length for an encryption
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key to be used in AES-CBC.
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"""
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def __init__(self, algorithm, bit_length, mode, passphrase=None):
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self.algorithm = algorithm
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self.bit_length = bit_length
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self.mode = mode
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self.passphrase = passphrase
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class ResponseDTO(object):
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"""Data transfer object for secret generation response.
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Barbican guarantees that both the ``cypher_text`` and
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``kek_metadata_extended`` will be persisted and then given back to
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the plugin when requesting a decryption operation.
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``kek_metadata_extended`` takes the idea of Key Encryption Key
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(KEK) metadata further by giving plugins the option to store
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secret-level KEK metadata. One example of using secret-level KEK
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metadata would be plugins that want to use a unique KEK for every
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secret that is encrypted. Such a plugin could use
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``kek_metadata_extended`` to store the Key ID for the KEK used to
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encrypt this particular secret.
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:param cypher_text: Byte data resulting from the encryption of the
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secret data.
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:param kek_meta_extended: Optional String object to be persisted alongside
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the cyphertext.
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"""
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def __init__(self, cypher_text, kek_meta_extended=None):
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self.cypher_text = cypher_text
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self.kek_meta_extended = kek_meta_extended
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class DecryptDTO(object):
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"""Secret Decryption DTO
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Data Transfer Object used to pass all the necessary data for the plugin
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to perform decryption of a secret.
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Currently, this DTO only contains the data produced by the plugin during
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encryption, but in the future this DTO will contain more information, such
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as a transport key for secret wrapping back to the client.
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.. attribute:: encrypted
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The data that was produced by the plugin during encryption. For some
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plugins this will be the actual bytes that need to be decrypted to
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produce the secret. In other implementations, this may just be a
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reference to some external system that can produce the unencrypted
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secret.
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"""
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def __init__(self, encrypted):
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self.encrypted = encrypted
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class EncryptDTO(object):
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"""Secret Encryption DTO
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Data Transfer Object used to pass all the necessary data for the plugin
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to perform encryption of a secret.
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Currently, this DTO only contains the raw bytes to be encrypted by the
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plugin, but in the future this may contain more information.
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.. attribute:: unencrypted
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The secret data in Bytes to be encrypted by the plugin.
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"""
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def __init__(self, unencrypted):
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self.unencrypted = unencrypted
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@six.add_metaclass(abc.ABCMeta)
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class CryptoPluginBase(object):
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"""Base class for all Crypto plugins.
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Barbican requests operations by invoking the methods on an instance of the
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implementing class. Barbican's plugin manager handles the life-cycle of
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the Data Transfer Objects (DTOs) that are passed into these methods, and
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persist the data that is assigned to these DTOs by the plugin.
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"""
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@abc.abstractmethod
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def encrypt(self, encrypt_dto, kek_meta_dto, project_id):
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"""Encryption handler function
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This method will be called by Barbican when requesting an encryption
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operation on a secret on behalf of a project.
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:param encrypt_dto: :class:`EncryptDTO` instance containing the raw
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secret byte data to be encrypted.
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:type encrypt_dto: :class:`EncryptDTO`
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:param kek_meta_dto: :class:`KEKMetaDTO` instance containing
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information about the project's Key Encryption Key (KEK) to be
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used for encryption. Plugins may assume that binding via
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:meth:`bind_kek_metadata` has already taken place before this
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instance is passed in.
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:type kek_meta_dto: :class:`KEKMetaDTO`
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:param project_id: Project ID associated with the unencrypted data.
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:return: A response DTO containing the cyphertext and KEK information.
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:rtype: :class:`ResponseDTO`
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"""
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raise NotImplementedError # pragma: no cover
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@abc.abstractmethod
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def decrypt(self, decrypt_dto, kek_meta_dto, kek_meta_extended,
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project_id):
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"""Decrypt encrypted_datum in the context of the provided project.
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:param decrypt_dto: data transfer object containing the cyphertext
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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 project_id: Project ID associated with the encrypted datum.
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:returns: str -- unencrypted byte data
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"""
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raise NotImplementedError # pragma: no cover
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@abc.abstractmethod
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def bind_kek_metadata(self, kek_meta_dto):
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"""Key Encryption Key Metadata binding function
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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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raise NotImplementedError # pragma: no cover
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@abc.abstractmethod
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def generate_symmetric(self, generate_dto, kek_meta_dto, project_id):
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"""Generate a new key.
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:param generate_dto: data transfer object for the record
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associated with this generation request. Some relevant
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parameters can be extracted from this object, including
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bit_length, algorithm and mode
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:param kek_meta_dto: Key encryption key metadata to use for decryption
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:param project_id: Project ID associated with the data.
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:returns: An object of type ResponseDTO containing encrypted data and
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kek_meta_extended, the former the resultant cypher text, the latter
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being optional per-secret metadata needed to decrypt (over and
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above the per-project metadata managed outside of the plugins)
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"""
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raise NotImplementedError # pragma: no cover
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@abc.abstractmethod
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def generate_asymmetric(self, generate_dto, kek_meta_dto, project_id):
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"""Create a new asymmetric key.
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:param generate_dto: data transfer object for the record
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associated with this generation request. Some relevant
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parameters can be extracted from this object, including
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bit_length, algorithm and passphrase
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:param kek_meta_dto: Key encryption key metadata to use for decryption
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:param project_id: Project ID associated with the data.
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:returns: A tuple containing objects for private_key, public_key and
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optionally one for passphrase. The objects will be of type
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ResponseDTO.
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Each object containing encrypted data and kek_meta_extended, the
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former the resultant cypher text, the latter being optional
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per-secret metadata needed to decrypt (over and above the
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per-project metadata managed outside of the plugins)
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"""
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raise NotImplementedError # pragma: no cover
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@abc.abstractmethod
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def supports(self, type_enum, algorithm=None, bit_length=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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raise NotImplementedError # pragma: no cover
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