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# Copyright 2015, Tresys Technology, LLC
# Copyright 2018, Chris PeBenito <pebenito@ieee.org>
#
# This file is part of SETools.
#
# SETools is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as
# published by the Free Software Foundation, either version 2.1 of
# the License, or (at your option) any later version.
#
# SETools is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with SETools. If not, see
# <http://www.gnu.org/licenses/>.
#
from collections import defaultdict, namedtuple
from .descriptors import DiffResultDescriptor
from .difference import Difference, SymbolWrapper
from .types import type_wrapper_factory
modified_roles_record = namedtuple("modified_role", ["added_types",
"removed_types",
"matched_types"])
_roles_cache = defaultdict(dict)
def role_wrapper_factory(role):
"""
Wrap roles from the specified policy.
This caches results to prevent duplicate wrapper
objects in memory.
"""
try:
return _roles_cache[role.policy][role]
except KeyError:
r = SymbolWrapper(role)
_roles_cache[role.policy][role] = r
return r
class RolesDifference(Difference):
"""Determine the difference in roles between two policies."""
added_roles = DiffResultDescriptor("diff_roles")
removed_roles = DiffResultDescriptor("diff_roles")
modified_roles = DiffResultDescriptor("diff_roles")
def diff_roles(self):
"""Generate the difference in roles between the policies."""
self.log.info(
"Generating role differences from {0.left_policy} to {0.right_policy}".format(self))
self.added_roles, self.removed_roles, matched_roles = self._set_diff(
(role_wrapper_factory(r) for r in self.left_policy.roles()),
(role_wrapper_factory(r) for r in self.right_policy.roles()))
self.modified_roles = dict()
for left_role, right_role in matched_roles:
# Criteria for modified roles
# 1. change to type set, or
# 2. change to attribute set (not implemented)
added_types, removed_types, matched_types = self._set_diff(
(type_wrapper_factory(t) for t in left_role.types()),
(type_wrapper_factory(t) for t in right_role.types()))
if added_types or removed_types:
self.modified_roles[left_role] = modified_roles_record(added_types,
removed_types,
matched_types)
#
# Internal functions
#
def _reset_diff(self):
"""Reset diff results on policy changes."""
self.log.debug("Resetting role differences")
self.added_roles = None
self.removed_roles = None
self.modified_roles = None