manila/manila/policy.py

242 lines
8.9 KiB
Python

# 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 Manila"""
import functools
import sys
from oslo_config import cfg
from oslo_log import log as logging
from oslo_policy import opts
from oslo_policy import policy
from oslo_utils import excutils
from manila import exception
from manila import policies
CONF = cfg.CONF
LOG = logging.getLogger(__name__)
_ENFORCER = None
# TODO(gmann): Remove setting the default value of config policy_file
# once oslo_policy change the default value to 'policy.yaml'.
# https://github.com/openstack/oslo.policy/blob/a626ad12fe5a3abd49d70e3e5b95589d279ab578/oslo_policy/opts.py#L49
DEFAULT_POLICY_FILE = 'policy.yaml'
opts.set_defaults(CONF, DEFAULT_POLICY_FILE)
def reset():
global _ENFORCER
if _ENFORCER:
_ENFORCER.clear()
_ENFORCER = None
def init(rules=None, use_conf=True, suppress_deprecation_warnings=False):
"""Init an Enforcer class.
:param policy_file: Custom policy file to use, if none is specified,
`CONF.policy_file` will be used.
:param rules: Default dictionary / Rules to use. It will be
considered just in the first instantiation.
:param use_conf: Whether to load rules from config file.
:param suppress_deprecation_warnings: Whether to suppress policy
deprecation warnings.
"""
global _ENFORCER
if not _ENFORCER:
_ENFORCER = policy.Enforcer(CONF,
rules=rules,
use_conf=use_conf)
# NOTE(gouthamr): Explicitly disable the warnings for policies
# changing their default check_str. During
# secure-rbac / policy-defaults-refresh work, all the policy
# defaults have been changed and warning for each policy started
# filling the log limits for various tools. Once we move to new
# defaults only world then we can enable these warning again.
_ENFORCER.suppress_default_change_warnings = True
# Suppressing deprecation warnings is fine for tests. However we
# won't do it by default
_ENFORCER.suppress_deprecation_warnings = suppress_deprecation_warnings
register_rules(_ENFORCER)
def enforce(context, action, target, do_raise=True):
"""Verifies that the action is valid on the target in this context.
**IMPORTANT** ONLY for use in API extensions. This method ignores
unregistered rules and applies a default rule on them; there should
be no unregistered rules in first party manila APIs.
:param context: manila context
:param action: string representing the action to be checked,
this should be colon separated for clarity.
i.e. ``share:create``,
: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: Whether to raise an exception if check fails.
:returns: When ``do_raise`` is ``False``, returns a value that
evaluates as ``True`` or ``False`` depending on whether
the policy allows action on the target.
:raises: manila.exception.PolicyNotAuthorized if verification fails
and ``do_raise`` is ``True``.
"""
init()
try:
return _ENFORCER.enforce(action,
target,
context,
do_raise=do_raise,
exc=exception.PolicyNotAuthorized,
action=action)
except policy.InvalidScope:
raise exception.PolicyNotAuthorized(action=action)
def set_rules(rules, overwrite=True, use_conf=False):
"""Set rules based on the provided dict of rules.
:param rules: New rules to use. It should be an instance of dict.
:param overwrite: Whether to overwrite current rules or update them
with the new rules.
:param use_conf: Whether to reload rules from config file.
"""
init(use_conf=False)
_ENFORCER.set_rules(rules, overwrite, use_conf)
def get_rules():
if _ENFORCER:
return _ENFORCER.rules
def register_rules(enforcer):
enforcer.register_defaults(policies.list_rules())
def get_enforcer():
# This method is for use by oslopolicy CLI scripts. Those scripts need the
# 'output-file' and 'namespace' options, but having those in sys.argv means
# loading the Manila config options will fail as those are not expected to
# be present. So we pass in an arg list with those stripped out.
conf_args = []
# Start at 1 because cfg.CONF expects the equivalent of sys.argv[1:]
i = 1
while i < len(sys.argv):
if sys.argv[i].strip('-') in ['namespace', 'output-file']:
i += 2
continue
conf_args.append(sys.argv[i])
i += 1
cfg.CONF(conf_args, project='manila')
init()
return _ENFORCER
def authorize(context, action, target, do_raise=True, exc=None):
"""Verifies that the action is valid on the target in this context.
:param context: manila context
:param action: string representing the action to be checked
this should be colon separated for clarity.
i.e. ``share:create``,
: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
:param exc: Class of the exception to raise if the check fails.
Any remaining arguments passed to :meth:`authorize` (both
positional and keyword arguments) will be passed to
the exception class. If not specified,
:class:`PolicyNotAuthorized` will be used.
:raises manila.exception.PolicyNotAuthorized: if verification fails
and do_raise is True. Or if 'exc' is specified it will raise an
exception of that type.
: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()
if not exc:
exc = exception.PolicyNotAuthorized
target = target or default_target(context)
try:
result = _ENFORCER.authorize(action, target, context,
do_raise=do_raise, exc=exc, action=action)
except policy.PolicyNotRegistered:
with excutils.save_and_reraise_exception():
LOG.exception('Policy not registered')
except policy.InvalidScope:
if do_raise:
raise exception.PolicyNotAuthorized(action=action)
else:
return False
except Exception:
with excutils.save_and_reraise_exception():
msg_args = {
'action': action,
'credentials': context.to_policy_values(),
}
LOG.debug('Policy check for %(action)s failed with credentials '
'%(credentials)s', msg_args)
return result
def default_target(context):
return {'project_id': context.project_id, 'user_id': context.user_id}
def check_is_admin(context):
"""Whether or not user is admin according to policy setting.
"""
# the target is user-self
target = default_target(context)
return authorize(context, 'context_is_admin', target, do_raise=False)
def wrap_check_policy(resource):
"""Check policy corresponding to the wrapped methods prior to execution."""
def check_policy_wraper(func):
@functools.wraps(func)
def wrapped(self, context, target_obj, *args, **kwargs):
check_policy(context, resource, func.__name__, target_obj)
return func(self, context, target_obj, *args, **kwargs)
return wrapped
return check_policy_wraper
def check_policy(context, resource, action, target_obj=None, do_raise=True):
target = target_obj or default_target(context)
_action = '%s:%s' % (resource, action)
return authorize(context, _action, target, do_raise=do_raise)