5ff3439df5
The constants of log levels were added in the 1.8 version of the oslo.log library. So we can replace all usage of system logging module with log module from oslo.log. Change-Id: I2992df0bec6337aefa8a75d4853b132bd134fa42 Closes-Bug: 1481370
424 lines
17 KiB
Python
424 lines
17 KiB
Python
# Copyright (c) 2012 OpenStack Foundation.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# 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, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""
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Policy engine for neutron. Largely copied from nova.
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"""
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import collections
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import re
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from oslo_config import cfg
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from oslo_log import log as logging
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from oslo_policy import policy
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from oslo_utils import excutils
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from oslo_utils import importutils
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import six
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from neutron.api.v2 import attributes
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from neutron.common import constants as const
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from neutron.common import exceptions
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from neutron.i18n import _LE, _LW
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LOG = logging.getLogger(__name__)
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_ENFORCER = None
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ADMIN_CTX_POLICY = 'context_is_admin'
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ADVSVC_CTX_POLICY = 'context_is_advsvc'
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def reset():
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global _ENFORCER
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if _ENFORCER:
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_ENFORCER.clear()
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_ENFORCER = None
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def init(conf=cfg.CONF, policy_file=None):
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"""Init an instance of the Enforcer class."""
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global _ENFORCER
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if not _ENFORCER:
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_ENFORCER = policy.Enforcer(conf, policy_file=policy_file)
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_ENFORCER.load_rules(True)
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def refresh(policy_file=None):
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"""Reset policy and init a new instance of Enforcer."""
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reset()
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init(policy_file=policy_file)
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def get_resource_and_action(action, pluralized=None):
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"""Extract resource and action (write, read) from api operation."""
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data = action.split(':', 1)[0].split('_', 1)
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resource = pluralized or ("%ss" % data[-1])
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return (resource, data[0] != 'get')
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def set_rules(policies, overwrite=True):
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"""Set rules based on the provided dict of rules.
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:param policies: New policies to use. It should be an instance of dict.
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:param overwrite: Whether to overwrite current rules or update them
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with the new rules.
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"""
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LOG.debug("Loading policies from file: %s", _ENFORCER.policy_path)
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init()
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_ENFORCER.set_rules(policies, overwrite)
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def _is_attribute_explicitly_set(attribute_name, resource, target, action):
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"""Verify that an attribute is present and is explicitly set."""
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if 'update' in action:
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# In the case of update, the function should not pay attention to a
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# default value of an attribute, but check whether it was explicitly
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# marked as being updated instead.
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return (attribute_name in target[const.ATTRIBUTES_TO_UPDATE] and
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target[attribute_name] is not attributes.ATTR_NOT_SPECIFIED)
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return ('default' in resource[attribute_name] and
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attribute_name in target and
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target[attribute_name] is not attributes.ATTR_NOT_SPECIFIED and
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target[attribute_name] != resource[attribute_name]['default'])
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def _should_validate_sub_attributes(attribute, sub_attr):
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"""Verify that sub-attributes are iterable and should be validated."""
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validate = attribute.get('validate')
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return (validate and isinstance(sub_attr, collections.Iterable) and
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any([k.startswith('type:dict') and
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v for (k, v) in six.iteritems(validate)]))
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def _build_subattr_match_rule(attr_name, attr, action, target):
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"""Create the rule to match for sub-attribute policy checks."""
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# TODO(salv-orlando): Instead of relying on validator info, introduce
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# typing for API attributes
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# Expect a dict as type descriptor
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validate = attr['validate']
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key = list(filter(lambda k: k.startswith('type:dict'), validate.keys()))
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if not key:
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LOG.warn(_LW("Unable to find data type descriptor for attribute %s"),
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attr_name)
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return
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data = validate[key[0]]
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if not isinstance(data, dict):
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LOG.debug("Attribute type descriptor is not a dict. Unable to "
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"generate any sub-attr policy rule for %s.",
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attr_name)
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return
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sub_attr_rules = [policy.RuleCheck('rule', '%s:%s:%s' %
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(action, attr_name,
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sub_attr_name)) for
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sub_attr_name in data if sub_attr_name in
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target[attr_name]]
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return policy.AndCheck(sub_attr_rules)
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def _process_rules_list(rules, match_rule):
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"""Recursively walk a policy rule to extract a list of match entries."""
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if isinstance(match_rule, policy.RuleCheck):
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rules.append(match_rule.match)
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elif isinstance(match_rule, policy.AndCheck):
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for rule in match_rule.rules:
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_process_rules_list(rules, rule)
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return rules
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def _build_match_rule(action, target, pluralized):
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"""Create the rule to match for a given action.
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The policy rule to be matched is built in the following way:
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1) add entries for matching permission on objects
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2) add an entry for the specific action (e.g.: create_network)
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3) add an entry for attributes of a resource for which the action
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is being executed (e.g.: create_network:shared)
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4) add an entry for sub-attributes of a resource for which the
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action is being executed
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(e.g.: create_router:external_gateway_info:network_id)
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"""
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match_rule = policy.RuleCheck('rule', action)
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resource, is_write = get_resource_and_action(action, pluralized)
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# Attribute-based checks shall not be enforced on GETs
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if is_write:
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# assigning to variable with short name for improving readability
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res_map = attributes.RESOURCE_ATTRIBUTE_MAP
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if resource in res_map:
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for attribute_name in res_map[resource]:
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if _is_attribute_explicitly_set(attribute_name,
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res_map[resource],
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target, action):
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attribute = res_map[resource][attribute_name]
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if 'enforce_policy' in attribute:
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attr_rule = policy.RuleCheck('rule', '%s:%s' %
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(action, attribute_name))
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# Build match entries for sub-attributes
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if _should_validate_sub_attributes(
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attribute, target[attribute_name]):
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attr_rule = policy.AndCheck(
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[attr_rule, _build_subattr_match_rule(
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attribute_name, attribute,
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action, target)])
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match_rule = policy.AndCheck([match_rule, attr_rule])
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return match_rule
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# This check is registered as 'tenant_id' so that it can override
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# GenericCheck which was used for validating parent resource ownership.
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# This will prevent us from having to handling backward compatibility
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# for policy.json
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# TODO(salv-orlando): Reinstate GenericCheck for simple tenant_id checks
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@policy.register('tenant_id')
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class OwnerCheck(policy.Check):
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"""Resource ownership check.
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This check verifies the owner of the current resource, or of another
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resource referenced by the one under analysis.
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In the former case it falls back to a regular GenericCheck, whereas
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in the latter case it leverages the plugin to load the referenced
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resource and perform the check.
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"""
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def __init__(self, kind, match):
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# Process the match
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try:
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self.target_field = re.findall(r'^\%\((.*)\)s$',
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match)[0]
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except IndexError:
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err_reason = (_("Unable to identify a target field from:%s. "
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"Match should be in the form %%(<field_name>)s") %
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match)
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LOG.exception(err_reason)
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raise exceptions.PolicyInitError(
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policy="%s:%s" % (kind, match),
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reason=err_reason)
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super(OwnerCheck, self).__init__(kind, match)
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def __call__(self, target, creds, enforcer):
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if self.target_field not in target:
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# policy needs a plugin check
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# target field is in the form resource:field
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# however if they're not separated by a colon, use an underscore
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# as a separator for backward compatibility
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def do_split(separator):
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parent_res, parent_field = self.target_field.split(
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separator, 1)
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return parent_res, parent_field
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for separator in (':', '_'):
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try:
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parent_res, parent_field = do_split(separator)
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break
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except ValueError:
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LOG.debug("Unable to find ':' as separator in %s.",
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self.target_field)
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else:
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# If we are here split failed with both separators
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err_reason = (_("Unable to find resource name in %s") %
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self.target_field)
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LOG.exception(err_reason)
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raise exceptions.PolicyCheckError(
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policy="%s:%s" % (self.kind, self.match),
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reason=err_reason)
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parent_foreign_key = attributes.RESOURCE_FOREIGN_KEYS.get(
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"%ss" % parent_res, None)
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if not parent_foreign_key:
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err_reason = (_("Unable to verify match:%(match)s as the "
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"parent resource: %(res)s was not found") %
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{'match': self.match, 'res': parent_res})
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LOG.exception(err_reason)
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raise exceptions.PolicyCheckError(
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policy="%s:%s" % (self.kind, self.match),
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reason=err_reason)
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# NOTE(salv-orlando): This check currently assumes the parent
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# resource is handled by the core plugin. It might be worth
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# having a way to map resources to plugins so to make this
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# check more general
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# NOTE(ihrachys): if import is put in global, circular
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# import failure occurs
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manager = importutils.import_module('neutron.manager')
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f = getattr(manager.NeutronManager.get_instance().plugin,
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'get_%s' % parent_res)
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# f *must* exist, if not found it is better to let neutron
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# explode. Check will be performed with admin context
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context = importutils.import_module('neutron.context')
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try:
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data = f(context.get_admin_context(),
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target[parent_foreign_key],
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fields=[parent_field])
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target[self.target_field] = data[parent_field]
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except Exception:
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with excutils.save_and_reraise_exception():
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LOG.exception(_LE('Policy check error while calling %s!'),
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f)
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match = self.match % target
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if self.kind in creds:
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return match == six.text_type(creds[self.kind])
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return False
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@policy.register('field')
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class FieldCheck(policy.Check):
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def __init__(self, kind, match):
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# Process the match
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resource, field_value = match.split(':', 1)
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field, value = field_value.split('=', 1)
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super(FieldCheck, self).__init__(kind, '%s:%s:%s' %
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(resource, field, value))
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# Value might need conversion - we need help from the attribute map
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try:
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attr = attributes.RESOURCE_ATTRIBUTE_MAP[resource][field]
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conv_func = attr['convert_to']
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except KeyError:
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conv_func = lambda x: x
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self.field = field
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self.value = conv_func(value)
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def __call__(self, target_dict, cred_dict, enforcer):
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target_value = target_dict.get(self.field)
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# target_value might be a boolean, explicitly compare with None
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if target_value is None:
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LOG.debug("Unable to find requested field: %(field)s in target: "
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"%(target_dict)s",
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{'field': self.field, 'target_dict': target_dict})
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return False
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return target_value == self.value
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def _prepare_check(context, action, target, pluralized):
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"""Prepare rule, target, and credentials for the policy engine."""
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# Compare with None to distinguish case in which target is {}
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if target is None:
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target = {}
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match_rule = _build_match_rule(action, target, pluralized)
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credentials = context.to_dict()
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return match_rule, target, credentials
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def log_rule_list(match_rule):
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if LOG.isEnabledFor(logging.DEBUG):
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rules = _process_rules_list([], match_rule)
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LOG.debug("Enforcing rules: %s", rules)
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def check(context, action, target, plugin=None, might_not_exist=False,
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pluralized=None):
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"""Verifies that the action is valid on the target in this context.
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:param context: neutron context
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:param action: string representing the action to be checked
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this should be colon separated for clarity.
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:param target: dictionary representing the object of the action
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for object creation this should be a dictionary representing the
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location of the object e.g. ``{'project_id': context.project_id}``
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:param plugin: currently unused and deprecated.
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Kept for backward compatibility.
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:param might_not_exist: If True the policy check is skipped (and the
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function returns True) if the specified policy does not exist.
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Defaults to false.
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:param pluralized: pluralized case of resource
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e.g. firewall_policy -> pluralized = "firewall_policies"
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:return: Returns True if access is permitted else False.
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"""
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# If we already know the context has admin rights do not perform an
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# additional check and authorize the operation
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if context.is_admin:
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return True
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if might_not_exist and not (_ENFORCER.rules and action in _ENFORCER.rules):
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return True
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match_rule, target, credentials = _prepare_check(context,
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action,
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target,
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pluralized)
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result = _ENFORCER.enforce(match_rule,
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target,
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credentials,
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pluralized=pluralized)
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# logging applied rules in case of failure
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if not result:
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log_rule_list(match_rule)
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return result
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def enforce(context, action, target, plugin=None, pluralized=None):
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"""Verifies that the action is valid on the target in this context.
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:param context: neutron context
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:param action: string representing the action to be checked
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this should be colon separated for clarity.
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:param target: dictionary representing the object of the action
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for object creation this should be a dictionary representing the
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location of the object e.g. ``{'project_id': context.project_id}``
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:param plugin: currently unused and deprecated.
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Kept for backward compatibility.
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:param pluralized: pluralized case of resource
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e.g. firewall_policy -> pluralized = "firewall_policies"
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:raises oslo_policy.policy.PolicyNotAuthorized:
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if verification fails.
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"""
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# If we already know the context has admin rights do not perform an
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# additional check and authorize the operation
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if context.is_admin:
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return True
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rule, target, credentials = _prepare_check(context,
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action,
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target,
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pluralized)
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try:
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result = _ENFORCER.enforce(rule, target, credentials, action=action,
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do_raise=True)
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except policy.PolicyNotAuthorized:
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with excutils.save_and_reraise_exception():
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log_rule_list(rule)
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LOG.debug("Failed policy check for '%s'", action)
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return result
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def check_is_admin(context):
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"""Verify context has admin rights according to policy settings."""
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init()
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# the target is user-self
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credentials = context.to_dict()
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if ADMIN_CTX_POLICY not in _ENFORCER.rules:
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return False
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return _ENFORCER.enforce(ADMIN_CTX_POLICY, credentials, credentials)
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def check_is_advsvc(context):
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"""Verify context has advsvc rights according to policy settings."""
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init()
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# the target is user-self
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credentials = context.to_dict()
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if ADVSVC_CTX_POLICY not in _ENFORCER.rules:
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return False
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return _ENFORCER.enforce(ADVSVC_CTX_POLICY, credentials, credentials)
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def _extract_roles(rule, roles):
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if isinstance(rule, policy.RoleCheck):
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roles.append(rule.match.lower())
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elif isinstance(rule, policy.RuleCheck):
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_extract_roles(_ENFORCER.rules[rule.match], roles)
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elif hasattr(rule, 'rules'):
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for rule in rule.rules:
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_extract_roles(rule, roles)
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