/usr/lib/python2.7/dist-packages/oslo_policy/_checks.py is in python-oslo.policy 1.6.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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#
# Copyright (c) 2015 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.
import abc
import ast
import contextlib
import copy
from oslo_serialization import jsonutils
import requests
import six
registered_checks = {}
@six.add_metaclass(abc.ABCMeta)
class BaseCheck(object):
"""Abstract base class for Check classes."""
@abc.abstractmethod
def __str__(self):
"""String representation of the Check tree rooted at this node."""
pass
@abc.abstractmethod
def __call__(self, target, cred, enforcer):
"""Triggers if instance of the class is called.
Performs the check. Returns False to reject the access or a
true value (not necessary True) to accept the access.
"""
pass
class FalseCheck(BaseCheck):
"""A policy check that always returns ``False`` (disallow)."""
def __str__(self):
"""Return a string representation of this check."""
return '!'
def __call__(self, target, cred, enforcer):
"""Check the policy."""
return False
class TrueCheck(BaseCheck):
"""A policy check that always returns ``True`` (allow)."""
def __str__(self):
"""Return a string representation of this check."""
return '@'
def __call__(self, target, cred, enforcer):
"""Check the policy."""
return True
class Check(BaseCheck):
def __init__(self, kind, match):
self.kind = kind
self.match = match
def __str__(self):
"""Return a string representation of this check."""
return '%s:%s' % (self.kind, self.match)
class NotCheck(BaseCheck):
def __init__(self, rule):
self.rule = rule
def __str__(self):
"""Return a string representation of this check."""
return 'not %s' % self.rule
def __call__(self, target, cred, enforcer):
"""Check the policy.
Returns the logical inverse of the wrapped check.
"""
return not self.rule(target, cred, enforcer)
class AndCheck(BaseCheck):
def __init__(self, rules):
self.rules = rules
def __str__(self):
"""Return a string representation of this check."""
return '(%s)' % ' and '.join(str(r) for r in self.rules)
def __call__(self, target, cred, enforcer):
"""Check the policy.
Requires that all rules accept in order to return True.
"""
for rule in self.rules:
if not rule(target, cred, enforcer):
return False
return True
def add_check(self, rule):
"""Adds rule to be tested.
Allows addition of another rule to the list of rules that will
be tested.
:returns: self
:rtype: :class:`.AndCheck`
"""
self.rules.append(rule)
return self
class OrCheck(BaseCheck):
def __init__(self, rules):
self.rules = rules
def __str__(self):
"""Return a string representation of this check."""
return '(%s)' % ' or '.join(str(r) for r in self.rules)
def __call__(self, target, cred, enforcer):
"""Check the policy.
Requires that at least one rule accept in order to return True.
"""
for rule in self.rules:
if rule(target, cred, enforcer):
return True
return False
def add_check(self, rule):
"""Adds rule to be tested.
Allows addition of another rule to the list of rules that will
be tested. Returns the OrCheck object for convenience.
"""
self.rules.append(rule)
return self
def pop_check(self):
"""Pops the last check from the list and returns them
:returns: self, the popped check
:rtype: :class:`.OrCheck`, class:`.Check`
"""
check = self.rules.pop()
return self, check
def register(name, func=None):
# Perform the actual decoration by registering the function or
# class. Returns the function or class for compliance with the
# decorator interface.
def decorator(func):
registered_checks[name] = func
return func
# If the function or class is given, do the registration
if func:
return decorator(func)
return decorator
@register('rule')
class RuleCheck(Check):
def __call__(self, target, creds, enforcer):
try:
return enforcer.rules[self.match](target, creds, enforcer)
except KeyError:
# We don't have any matching rule; fail closed
return False
@register('role')
class RoleCheck(Check):
"""Check that there is a matching role in the ``creds`` dict."""
def __call__(self, target, creds, enforcer):
try:
match = self.match % target
except KeyError:
# While doing RoleCheck if key not
# present in Target return false
return False
if 'roles' in creds:
return match.lower() in [x.lower() for x in creds['roles']]
return False
@register('http')
class HttpCheck(Check):
"""Check ``http:`` rules by calling to a remote server.
This example implementation simply verifies that the response
is exactly ``True``.
"""
def __call__(self, target, creds, enforcer):
url = ('http:' + self.match) % target
# Convert instances of object() in target temporarily to
# empty dict to avoid circular reference detection
# errors in jsonutils.dumps().
temp_target = copy.deepcopy(target)
for key in target.keys():
element = target.get(key)
if type(element) is object:
temp_target[key] = {}
data = {'target': jsonutils.dumps(temp_target),
'credentials': jsonutils.dumps(creds)}
with contextlib.closing(requests.post(url, data=data)) as r:
return r.text == 'True'
@register(None)
class GenericCheck(Check):
"""Check an individual match.
Matches look like:
- tenant:%(tenant_id)s
- role:compute:admin
- True:%(user.enabled)s
- 'Member':%(role.name)s
"""
def _find_in_dict(self, test_value, path_segments, match):
'''Searches for a match in the dictionary.
test_value is a reference inside the dictionary. Since the process is
recursive, each call to _find_in_dict will be one level deeper.
path_segments is the segments of the path to search. The recursion
ends when there are no more segments of path.
When specifying a value inside a list, each element of the list is
checked for a match. If the value is found within any of the sub lists
the check succeeds; The check only fails if the entry is not in any of
the sublists.
'''
if len(path_segments) == 0:
return match == six.text_type(test_value)
key, path_segments = path_segments[0], path_segments[1:]
try:
test_value = test_value[key]
except KeyError:
return False
if isinstance(test_value, list):
for val in test_value:
if self._find_in_dict(val, path_segments, match):
return True
return False
else:
return self._find_in_dict(test_value, path_segments, match)
def __call__(self, target, creds, enforcer):
try:
match = self.match % target
except KeyError:
# While doing GenericCheck if key not
# present in Target return false
return False
try:
# Try to interpret self.kind as a literal
test_value = ast.literal_eval(self.kind)
return match == six.text_type(test_value)
except ValueError:
pass
path_segments = self.kind.split('.')
return self._find_in_dict(creds, path_segments, match)
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