keystone/keystone/token/providers/fernet/token_formatters.py

676 lines
26 KiB
Python

# 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 base64
import datetime
import struct
import uuid
from cryptography import fernet
import msgpack
from oslo_config import cfg
from oslo_log import log
from oslo_utils import timeutils
import six
from six.moves import map
from keystone.auth import plugins as auth_plugins
from keystone.common import utils as ks_utils
from keystone import exception
from keystone.i18n import _, _LI
from keystone.token import provider
from keystone.token.providers.fernet import utils
CONF = cfg.CONF
LOG = log.getLogger(__name__)
# Fernet byte indexes as as computed by pypi/keyless_fernet and defined in
# https://github.com/fernet/spec
TIMESTAMP_START = 1
TIMESTAMP_END = 9
class TokenFormatter(object):
"""Packs and unpacks payloads into tokens for transport."""
@property
def crypto(self):
"""Return a cryptography instance.
You can extend this class with a custom crypto @property to provide
your own token encoding / decoding. For example, using a different
cryptography library (e.g. ``python-keyczar``) or to meet arbitrary
security requirements.
This @property just needs to return an object that implements
``encrypt(plaintext)`` and ``decrypt(ciphertext)``.
"""
keys = utils.load_keys()
if not keys:
raise exception.KeysNotFound()
fernet_instances = [fernet.Fernet(key) for key in keys]
return fernet.MultiFernet(fernet_instances)
def pack(self, payload):
"""Pack a payload for transport as a token."""
# base64 padding (if any) is not URL-safe
return self.crypto.encrypt(payload).rstrip('=')
def unpack(self, token):
"""Unpack a token, and validate the payload."""
token = six.binary_type(token)
# Restore padding on token before decoding it
token = TokenFormatter.restore_padding(token)
try:
return self.crypto.decrypt(token)
except fernet.InvalidToken:
raise exception.ValidationError(
_('This is not a recognized Fernet token'))
@classmethod
def restore_padding(cls, token):
"""Restore padding based on token size.
:param token: token to restore padding on
:returns: token with correct padding
"""
# Re-inflate the padding
mod_returned = len(token) % 4
if mod_returned:
missing_padding = 4 - mod_returned
token += b'=' * missing_padding
return token
@classmethod
def creation_time(cls, fernet_token):
"""Returns the creation time of a valid Fernet token."""
# tokens may be transmitted as Unicode, but they're just ASCII
# (pypi/cryptography will refuse to operate on Unicode input)
fernet_token = six.binary_type(fernet_token)
# Restore padding on token before decoding it
fernet_token = TokenFormatter.restore_padding(fernet_token)
# fernet tokens are base64 encoded, so we need to unpack them first
token_bytes = base64.urlsafe_b64decode(fernet_token)
# slice into the byte array to get just the timestamp
timestamp_bytes = token_bytes[TIMESTAMP_START:TIMESTAMP_END]
# convert those bytes to an integer
# (it's a 64-bit "unsigned long long int" in C)
timestamp_int = struct.unpack(">Q", timestamp_bytes)[0]
# and with an integer, it's trivial to produce a datetime object
created_at = datetime.datetime.utcfromtimestamp(timestamp_int)
return created_at
def create_token(self, user_id, expires_at, audit_ids, methods=None,
domain_id=None, project_id=None, trust_id=None,
federated_info=None):
"""Given a set of payload attributes, generate a Fernet token."""
if trust_id:
version = TrustScopedPayload.version
payload = TrustScopedPayload.assemble(
user_id,
methods,
project_id,
expires_at,
audit_ids,
trust_id)
elif project_id and federated_info:
version = FederatedProjectScopedPayload.version
payload = FederatedProjectScopedPayload.assemble(
user_id,
methods,
project_id,
expires_at,
audit_ids,
federated_info)
elif domain_id and federated_info:
version = FederatedDomainScopedPayload.version
payload = FederatedDomainScopedPayload.assemble(
user_id,
methods,
domain_id,
expires_at,
audit_ids,
federated_info)
elif federated_info:
version = FederatedUnscopedPayload.version
payload = FederatedUnscopedPayload.assemble(
user_id,
methods,
expires_at,
audit_ids,
federated_info)
elif project_id:
version = ProjectScopedPayload.version
payload = ProjectScopedPayload.assemble(
user_id,
methods,
project_id,
expires_at,
audit_ids)
elif domain_id:
version = DomainScopedPayload.version
payload = DomainScopedPayload.assemble(
user_id,
methods,
domain_id,
expires_at,
audit_ids)
else:
version = UnscopedPayload.version
payload = UnscopedPayload.assemble(
user_id,
methods,
expires_at,
audit_ids)
versioned_payload = (version,) + payload
serialized_payload = msgpack.packb(versioned_payload)
token = self.pack(serialized_payload)
# NOTE(lbragstad): We should warn against Fernet tokens that are over
# 255 characters in length. This is mostly due to persisting the tokens
# in a backend store of some kind that might have a limit of 255
# characters. Even though Keystone isn't storing a Fernet token
# anywhere, we can't say it isn't being stored somewhere else with
# those kind of backend constraints.
if len(token) > 255:
LOG.info(_LI('Fernet token created with length of %d '
'characters, which exceeds 255 characters'),
len(token))
return token
def validate_token(self, token):
"""Validates a Fernet token and returns the payload attributes."""
# Convert v2 unicode token to a string
if not isinstance(token, six.binary_type):
token = token.encode('ascii')
serialized_payload = self.unpack(token)
versioned_payload = msgpack.unpackb(serialized_payload)
version, payload = versioned_payload[0], versioned_payload[1:]
# depending on the formatter, these may or may not be defined
domain_id = None
project_id = None
trust_id = None
federated_info = None
if version == UnscopedPayload.version:
(user_id, methods, expires_at, audit_ids) = (
UnscopedPayload.disassemble(payload))
elif version == DomainScopedPayload.version:
(user_id, methods, domain_id, expires_at, audit_ids) = (
DomainScopedPayload.disassemble(payload))
elif version == ProjectScopedPayload.version:
(user_id, methods, project_id, expires_at, audit_ids) = (
ProjectScopedPayload.disassemble(payload))
elif version == TrustScopedPayload.version:
(user_id, methods, project_id, expires_at, audit_ids, trust_id) = (
TrustScopedPayload.disassemble(payload))
elif version == FederatedUnscopedPayload.version:
(user_id, methods, expires_at, audit_ids, federated_info) = (
FederatedUnscopedPayload.disassemble(payload))
elif version == FederatedProjectScopedPayload.version:
(user_id, methods, project_id, expires_at, audit_ids,
federated_info) = FederatedProjectScopedPayload.disassemble(
payload)
elif version == FederatedDomainScopedPayload.version:
(user_id, methods, domain_id, expires_at, audit_ids,
federated_info) = FederatedDomainScopedPayload.disassemble(
payload)
else:
# If the token_format is not recognized, raise ValidationError.
raise exception.ValidationError(_(
'This is not a recognized Fernet payload version: %s') %
version)
# rather than appearing in the payload, the creation time is encoded
# into the token format itself
created_at = TokenFormatter.creation_time(token)
created_at = ks_utils.isotime(at=created_at, subsecond=True)
expires_at = timeutils.parse_isotime(expires_at)
expires_at = ks_utils.isotime(at=expires_at, subsecond=True)
return (user_id, methods, audit_ids, domain_id, project_id, trust_id,
federated_info, created_at, expires_at)
class BasePayload(object):
# each payload variant should have a unique version
version = None
@classmethod
def assemble(cls, *args):
"""Assemble the payload of a token.
:param args: whatever data should go into the payload
:returns: the payload of a token
"""
raise NotImplementedError()
@classmethod
def disassemble(cls, payload):
"""Disassemble an unscoped payload into the component data.
:param payload: this variant of payload
:returns: a tuple of the payloads component data
"""
raise NotImplementedError()
@classmethod
def convert_uuid_hex_to_bytes(cls, uuid_string):
"""Compress UUID formatted strings to bytes.
:param uuid_string: uuid string to compress to bytes
:returns: a byte representation of the uuid
"""
# TODO(lbragstad): Wrap this in an exception. Not sure what the case
# would be where we couldn't handle what we've been given but incase
# the integrity of the token has been compromised.
uuid_obj = uuid.UUID(uuid_string)
return uuid_obj.bytes
@classmethod
def convert_uuid_bytes_to_hex(cls, uuid_byte_string):
"""Generate uuid.hex format based on byte string.
:param uuid_byte_string: uuid string to generate from
:returns: uuid hex formatted string
"""
# TODO(lbragstad): Wrap this in an exception. Not sure what the case
# would be where we couldn't handle what we've been given but incase
# the integrity of the token has been compromised.
uuid_obj = uuid.UUID(bytes=uuid_byte_string)
return uuid_obj.hex
@classmethod
def _convert_time_string_to_int(cls, time_string):
"""Convert a time formatted string to a timestamp integer.
:param time_string: time formatted string
:returns: an integer timestamp
"""
time_object = timeutils.parse_isotime(time_string)
return (timeutils.normalize_time(time_object) -
datetime.datetime.utcfromtimestamp(0)).total_seconds()
@classmethod
def _convert_int_to_time_string(cls, time_int):
"""Convert a timestamp integer to a string.
:param time_int: integer representing timestamp
:returns: a time formatted strings
"""
time_object = datetime.datetime.utcfromtimestamp(time_int)
return ks_utils.isotime(time_object, subsecond=True)
@classmethod
def attempt_convert_uuid_hex_to_bytes(cls, value):
"""Attempt to convert value to bytes or return value.
:param value: value to attempt to convert to bytes
:returns: uuid value in bytes or value
"""
try:
return cls.convert_uuid_hex_to_bytes(value)
except ValueError:
# this might not be a UUID, depending on the situation (i.e.
# federation)
return value
@classmethod
def attempt_convert_uuid_bytes_to_hex(cls, value):
"""Attempt to convert value to hex or return value.
:param value: value to attempt to convert to hex
:returns: uuid value in hex or value
"""
try:
return cls.convert_uuid_bytes_to_hex(value)
except ValueError:
return value
class UnscopedPayload(BasePayload):
version = 0
@classmethod
def assemble(cls, user_id, methods, expires_at, audit_ids):
"""Assemble the payload of an unscoped token.
:param user_id: identifier of the user in the token request
:param methods: list of authentication methods used
:param expires_at: datetime of the token's expiration
:param audit_ids: list of the token's audit IDs
:returns: the payload of an unscoped token
"""
b_user_id = cls.attempt_convert_uuid_hex_to_bytes(user_id)
methods = auth_plugins.convert_method_list_to_integer(methods)
expires_at_int = cls._convert_time_string_to_int(expires_at)
b_audit_ids = list(map(provider.random_urlsafe_str_to_bytes,
audit_ids))
return (b_user_id, methods, expires_at_int, b_audit_ids)
@classmethod
def disassemble(cls, payload):
"""Disassemble an unscoped payload into the component data.
:param payload: the payload of an unscoped token
:return: a tuple containing the user_id, auth methods, expires_at, and
audit_ids
"""
user_id = cls.attempt_convert_uuid_bytes_to_hex(payload[0])
methods = auth_plugins.convert_integer_to_method_list(payload[1])
expires_at_str = cls._convert_int_to_time_string(payload[2])
audit_ids = list(map(provider.base64_encode, payload[3]))
return (user_id, methods, expires_at_str, audit_ids)
class DomainScopedPayload(BasePayload):
version = 1
@classmethod
def assemble(cls, user_id, methods, domain_id, expires_at, audit_ids):
"""Assemble the payload of a domain-scoped token.
:param user_id: ID of the user in the token request
:param methods: list of authentication methods used
:param domain_id: ID of the domain to scope to
:param expires_at: datetime of the token's expiration
:param audit_ids: list of the token's audit IDs
:returns: the payload of a domain-scoped token
"""
b_user_id = cls.attempt_convert_uuid_hex_to_bytes(user_id)
methods = auth_plugins.convert_method_list_to_integer(methods)
try:
b_domain_id = cls.convert_uuid_hex_to_bytes(domain_id)
except ValueError:
# the default domain ID is configurable, and probably isn't a UUID
if domain_id == CONF.identity.default_domain_id:
b_domain_id = domain_id
else:
raise
expires_at_int = cls._convert_time_string_to_int(expires_at)
b_audit_ids = list(map(provider.random_urlsafe_str_to_bytes,
audit_ids))
return (b_user_id, methods, b_domain_id, expires_at_int, b_audit_ids)
@classmethod
def disassemble(cls, payload):
"""Disassemble a payload into the component data.
:param payload: the payload of a token
:return: a tuple containing the user_id, auth methods, domain_id,
expires_at_str, and audit_ids
"""
user_id = cls.attempt_convert_uuid_bytes_to_hex(payload[0])
methods = auth_plugins.convert_integer_to_method_list(payload[1])
try:
domain_id = cls.convert_uuid_bytes_to_hex(payload[2])
except ValueError:
# the default domain ID is configurable, and probably isn't a UUID
if payload[2] == CONF.identity.default_domain_id:
domain_id = payload[2]
else:
raise
expires_at_str = cls._convert_int_to_time_string(payload[3])
audit_ids = list(map(provider.base64_encode, payload[4]))
return (user_id, methods, domain_id, expires_at_str, audit_ids)
class ProjectScopedPayload(BasePayload):
version = 2
@classmethod
def assemble(cls, user_id, methods, project_id, expires_at, audit_ids):
"""Assemble the payload of a project-scoped token.
:param user_id: ID of the user in the token request
:param methods: list of authentication methods used
:param project_id: ID of the project to scope to
:param expires_at: datetime of the token's expiration
:param audit_ids: list of the token's audit IDs
:returns: the payload of a project-scoped token
"""
b_user_id = cls.attempt_convert_uuid_hex_to_bytes(user_id)
methods = auth_plugins.convert_method_list_to_integer(methods)
b_project_id = cls.attempt_convert_uuid_hex_to_bytes(project_id)
expires_at_int = cls._convert_time_string_to_int(expires_at)
b_audit_ids = list(map(provider.random_urlsafe_str_to_bytes,
audit_ids))
return (b_user_id, methods, b_project_id, expires_at_int, b_audit_ids)
@classmethod
def disassemble(cls, payload):
"""Disassemble a payload into the component data.
:param payload: the payload of a token
:return: a tuple containing the user_id, auth methods, project_id,
expires_at_str, and audit_ids
"""
user_id = cls.attempt_convert_uuid_bytes_to_hex(payload[0])
methods = auth_plugins.convert_integer_to_method_list(payload[1])
project_id = cls.attempt_convert_uuid_bytes_to_hex(payload[2])
expires_at_str = cls._convert_int_to_time_string(payload[3])
audit_ids = list(map(provider.base64_encode, payload[4]))
return (user_id, methods, project_id, expires_at_str, audit_ids)
class TrustScopedPayload(BasePayload):
version = 3
@classmethod
def assemble(cls, user_id, methods, project_id, expires_at, audit_ids,
trust_id):
"""Assemble the payload of a trust-scoped token.
:param user_id: ID of the user in the token request
:param methods: list of authentication methods used
:param project_id: ID of the project to scope to
:param expires_at: datetime of the token's expiration
:param audit_ids: list of the token's audit IDs
:param trust_id: ID of the trust in effect
:returns: the payload of a trust-scoped token
"""
b_user_id = cls.attempt_convert_uuid_hex_to_bytes(user_id)
methods = auth_plugins.convert_method_list_to_integer(methods)
b_project_id = cls.attempt_convert_uuid_hex_to_bytes(project_id)
b_trust_id = cls.convert_uuid_hex_to_bytes(trust_id)
expires_at_int = cls._convert_time_string_to_int(expires_at)
b_audit_ids = list(map(provider.random_urlsafe_str_to_bytes,
audit_ids))
return (b_user_id, methods, b_project_id, expires_at_int, b_audit_ids,
b_trust_id)
@classmethod
def disassemble(cls, payload):
"""Validate a trust-based payload.
:param token_string: a string representing the token
:returns: a tuple containing the user_id, auth methods, project_id,
expires_at_str, audit_ids, and trust_id
"""
user_id = cls.attempt_convert_uuid_bytes_to_hex(payload[0])
methods = auth_plugins.convert_integer_to_method_list(payload[1])
project_id = cls.attempt_convert_uuid_bytes_to_hex(payload[2])
expires_at_str = cls._convert_int_to_time_string(payload[3])
audit_ids = list(map(provider.base64_encode, payload[4]))
trust_id = cls.convert_uuid_bytes_to_hex(payload[5])
return (user_id, methods, project_id, expires_at_str, audit_ids,
trust_id)
class FederatedUnscopedPayload(BasePayload):
version = 4
@classmethod
def pack_group_id(cls, group_dict):
return cls.attempt_convert_uuid_hex_to_bytes(group_dict['id'])
@classmethod
def unpack_group_id(cls, group_id_in_bytes):
group_id = cls.attempt_convert_uuid_bytes_to_hex(group_id_in_bytes)
return {'id': group_id}
@classmethod
def assemble(cls, user_id, methods, expires_at, audit_ids, federated_info):
"""Assemble the payload of a federated token.
:param user_id: ID of the user in the token request
:param methods: list of authentication methods used
:param expires_at: datetime of the token's expiration
:param audit_ids: list of the token's audit IDs
:param federated_info: dictionary containing group IDs, the identity
provider ID, protocol ID, and federated domain
ID
:returns: the payload of a federated token
"""
b_user_id = cls.attempt_convert_uuid_hex_to_bytes(user_id)
methods = auth_plugins.convert_method_list_to_integer(methods)
b_group_ids = list(map(cls.pack_group_id,
federated_info['group_ids']))
b_idp_id = cls.attempt_convert_uuid_hex_to_bytes(
federated_info['idp_id'])
protocol_id = federated_info['protocol_id']
expires_at_int = cls._convert_time_string_to_int(expires_at)
b_audit_ids = list(map(provider.random_urlsafe_str_to_bytes,
audit_ids))
return (b_user_id, methods, b_group_ids, b_idp_id, protocol_id,
expires_at_int, b_audit_ids)
@classmethod
def disassemble(cls, payload):
"""Validate a federated payload.
:param token_string: a string representing the token
:return: a tuple containing the user_id, auth methods, audit_ids, and a
dictionary containing federated information such as the group
IDs, the identity provider ID, the protocol ID, and the
federated domain ID
"""
user_id = cls.attempt_convert_uuid_bytes_to_hex(payload[0])
methods = auth_plugins.convert_integer_to_method_list(payload[1])
group_ids = list(map(cls.unpack_group_id, payload[2]))
idp_id = cls.attempt_convert_uuid_bytes_to_hex(payload[3])
protocol_id = payload[4]
expires_at_str = cls._convert_int_to_time_string(payload[5])
audit_ids = list(map(provider.base64_encode, payload[6]))
federated_info = dict(group_ids=group_ids, idp_id=idp_id,
protocol_id=protocol_id)
return (user_id, methods, expires_at_str, audit_ids, federated_info)
class FederatedScopedPayload(FederatedUnscopedPayload):
version = None
@classmethod
def assemble(cls, user_id, methods, scope_id, expires_at, audit_ids,
federated_info):
"""Assemble the project-scoped payload of a federated token.
:param user_id: ID of the user in the token request
:param methods: list of authentication methods used
:param scope_id: ID of the project or domain ID to scope to
:param expires_at: datetime of the token's expiration
:param audit_ids: list of the token's audit IDs
:param federated_info: dictionary containing the identity provider ID,
protocol ID, federated domain ID and group IDs
:returns: the payload of a federated token
"""
b_user_id = cls.attempt_convert_uuid_hex_to_bytes(user_id)
methods = auth_plugins.convert_method_list_to_integer(methods)
b_scope_id = cls.attempt_convert_uuid_hex_to_bytes(scope_id)
b_group_ids = list(map(cls.pack_group_id,
federated_info['group_ids']))
b_idp_id = cls.attempt_convert_uuid_hex_to_bytes(
federated_info['idp_id'])
protocol_id = federated_info['protocol_id']
expires_at_int = cls._convert_time_string_to_int(expires_at)
b_audit_ids = list(map(provider.random_urlsafe_str_to_bytes,
audit_ids))
return (b_user_id, methods, b_scope_id, b_group_ids, b_idp_id,
protocol_id, expires_at_int, b_audit_ids)
@classmethod
def disassemble(cls, payload):
"""Validate a project-scoped federated payload.
:param token_string: a string representing the token
:returns: a tuple containing the user_id, auth methods, scope_id,
expiration time (as str), audit_ids, and a dictionary
containing federated information such as the the identity
provider ID, the protocol ID, the federated domain ID and
group IDs
"""
user_id = cls.attempt_convert_uuid_bytes_to_hex(payload[0])
methods = auth_plugins.convert_integer_to_method_list(payload[1])
scope_id = cls.attempt_convert_uuid_bytes_to_hex(payload[2])
group_ids = list(map(cls.unpack_group_id, payload[3]))
idp_id = cls.attempt_convert_uuid_bytes_to_hex(payload[4])
protocol_id = payload[5]
expires_at_str = cls._convert_int_to_time_string(payload[6])
audit_ids = list(map(provider.base64_encode, payload[7]))
federated_info = dict(idp_id=idp_id, protocol_id=protocol_id,
group_ids=group_ids)
return (user_id, methods, scope_id, expires_at_str, audit_ids,
federated_info)
class FederatedProjectScopedPayload(FederatedScopedPayload):
version = 5
class FederatedDomainScopedPayload(FederatedScopedPayload):
version = 6