# Copyright 2016, Tresys Technology, LLC # Copyright 2018, Chris PeBenito <pebenito@ieee.org> # # SPDX-License-Identifier: LGPL-2.1-only # from collections import defaultdict from typing import NamedTuple from ..policyrep import SELinuxPolicy, Boolean from .descriptors import DiffResultDescriptor from .difference import Difference, SymbolWrapper from .typing import SymbolCache _bool_cache: SymbolCache[Boolean] = defaultdict(dict) class ModifiedBoolean(NamedTuple): """Difference details for a modified Boolean.""" added_state: bool removed_state: bool def boolean_wrapper(policy: SELinuxPolicy, boolean: Boolean) -> SymbolWrapper[Boolean]: """ Wrap booleans from the specified policy. This caches results to prevent duplicate wrapper objects in memory. """ try: return _bool_cache[policy][boolean] except KeyError: b = SymbolWrapper(boolean) _bool_cache[policy][boolean] = b return b class BooleansDifference(Difference): """Determine the difference in type attributes between two policies.""" added_booleans = DiffResultDescriptor("diff_booleans") removed_booleans = DiffResultDescriptor("diff_booleans") modified_booleans = DiffResultDescriptor("diff_booleans") def diff_booleans(self) -> None: """Generate the difference in type attributes between the policies.""" self.log.info("Generating Boolean differences from {0.left_policy} to {0.right_policy}". format(self)) self.added_booleans, self.removed_booleans, matched_booleans = \ self._set_diff( (SymbolWrapper(b) for b in self.left_policy.bools()), (SymbolWrapper(b) for b in self.right_policy.bools())) self.modified_booleans = dict() for left_boolean, right_boolean in matched_booleans: # Criteria for modified booleans # 1. change to default state if left_boolean.state != right_boolean.state: self.modified_booleans[left_boolean] = ModifiedBoolean(right_boolean.state, left_boolean.state) # # Internal functions # def _reset_diff(self) -> None: """Reset diff results on policy changes.""" self.log.debug("Resetting Boolean differences") self.added_booleans = None self.removed_booleans = None self.modified_booleans = None