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# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright (c) 2011 OpenStack Foundation
# 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 oslo.config import cfg
from nova import exception
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')),
]
CONF = cfg.CONF
CONF.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 = CONF.policy_file
if not os.path.exists(_POLICY_PATH):
_POLICY_PATH = CONF.find_file(_POLICY_PATH)
if not _POLICY_PATH:
raise exception.ConfigNotFound(path=CONF.policy_file)
utils.read_cached_file(_POLICY_PATH, _POLICY_CACHE,
reload_func=_set_rules)
def _set_rules(data):
default_rule = CONF.policy_default_rule
policy.set_rules(policy.Rules.load_json(data, default_rule))
def enforce(context, action, target, do_raise=True):
"""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 target: 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}``
:param do_raise: if True (the default), raises PolicyNotAuthorized;
if False, returns False
:raises nova.exception.PolicyNotAuthorized: if verification fails
and do_raise is True.
:return: returns a non-False value (not necessarily "True") if
authorized, and the exact value False if not authorized and
do_raise is False.
"""
init()
credentials = context.to_dict()
# Add the exception arguments if asked to do a raise
extra = {}
if do_raise:
extra.update(exc=exception.PolicyNotAuthorized, action=action)
return policy.check(action, target, credentials, **extra)
def check_is_admin(context):
"""Whether or not roles contains 'admin' role according to policy setting.
"""
init()
#the target is user-self
credentials = context.to_dict()
target = credentials
return policy.check('context_is_admin', target, credentials)
@policy.register('is_admin')
class IsAdminCheck(policy.Check):
"""An explicit check for is_admin."""
def __init__(self, kind, match):
"""Initialize the check."""
self.expected = (match.lower() == 'true')
super(IsAdminCheck, self).__init__(kind, str(self.expected))
def __call__(self, target, creds):
"""Determine whether is_admin matches the requested value."""
return creds['is_admin'] == self.expected
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