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# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright (c) 2011 OpenStack, LLC.
# All Rights Reserved.
#
# 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.
"""Policy Engine For Nova"""
import os.path
from nova import exception
from nova import flags
from nova.openstack.common import cfg
from nova.openstack.common import policy
from nova import utils
policy_opts = [
cfg.StrOpt('policy_file',
default='policy.json',
help=_('JSON file representing policy')),
cfg.StrOpt('policy_default_rule',
default='default',
help=_('Rule checked when requested rule is not found')),
]
FLAGS = flags.FLAGS
FLAGS.register_opts(policy_opts)
_POLICY_PATH = None
_POLICY_CACHE = {}
def reset():
global _POLICY_PATH
global _POLICY_CACHE
_POLICY_PATH = None
_POLICY_CACHE = {}
policy.reset()
def init():
global _POLICY_PATH
global _POLICY_CACHE
if not _POLICY_PATH:
_POLICY_PATH = FLAGS.policy_file
if not os.path.exists(_POLICY_PATH):
_POLICY_PATH = FLAGS.find_file(_POLICY_PATH)
if not _POLICY_PATH:
raise exception.ConfigNotFound(path=FLAGS.policy_file)
utils.read_cached_file(_POLICY_PATH, _POLICY_CACHE,
reload_func=_set_brain)
def _set_brain(data):
default_rule = FLAGS.policy_default_rule
policy.set_brain(policy.Brain.load_json(data, default_rule))
def enforce(context, action, target):
"""Verifies that the action is valid on the target in this context.
:param context: nova context
:param action: string representing the action to be checked
this should be colon separated for clarity.
i.e. ``compute:create_instance``,
``compute:attach_volume``,
``volume:attach_volume``
:param object: dictionary representing the object of the action
for object creation this should be a dictionary representing the
location of the object e.g. ``{'project_id': context.project_id}``
:raises nova.exception.PolicyNotAllowed: if verification fails.
"""
init()
match_list = ('rule:%s' % action,)
credentials = context.to_dict()
# NOTE(vish): This is to work around the following launchpad bug:
# https://bugs.launchpad.net/openstack-common/+bug/1039132
# It can be removed when that bug is fixed.
credentials['is_admin'] = unicode(credentials['is_admin'])
policy.enforce(match_list, target, credentials,
exception.PolicyNotAuthorized, action=action)
def check_is_admin(roles):
"""Whether or not roles contains 'admin' role according to policy setting.
"""
init()
action = 'context_is_admin'
match_list = ('rule:%s' % action,)
target = {}
credentials = {'roles': roles}
try:
policy.enforce(match_list, target, credentials,
exception.PolicyNotAuthorized, action=action)
except exception.PolicyNotAuthorized:
return False
return True
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