mirror of
https://github.com/SELinuxProject/setools
synced 2025-04-04 23:39:29 +00:00
134 lines
4.9 KiB
Python
134 lines
4.9 KiB
Python
# Copyright 2016, Tresys Technology, LLC
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#
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# This file is part of SETools.
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#
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# SETools is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License as
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# published by the Free Software Foundation, either version 2.1 of
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# the License, or (at your option) any later version.
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#
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# SETools is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with SETools. If not, see
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# <http://www.gnu.org/licenses/>.
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#
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from collections import namedtuple
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from .descriptors import DiffResultDescriptor
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from .difference import Difference, SymbolWrapper, Wrapper
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from .mls import RangeWrapper
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modified_mlsrule_record = namedtuple("modified_mlsrule", ["rule",
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"added_default",
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"removed_default"])
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class MLSRulesDifference(Difference):
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"""Determine the difference in MLS rules between two policies."""
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added_range_transitions = DiffResultDescriptor("diff_range_transitions")
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removed_range_transitions = DiffResultDescriptor("diff_range_transitions")
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modified_range_transitions = DiffResultDescriptor("diff_range_transitions")
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# Lists of rules for each policy
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_left_range_transitions = None
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_right_range_transitions = None
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def diff_range_transitions(self):
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"""Generate the difference in range_transition rules between the policies."""
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self.log.info(
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"Generating range_transition differences from {0.left_policy} to {0.right_policy}".
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format(self))
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if self._left_range_transitions is None or self._right_range_transitions is None:
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self._create_mls_rule_lists()
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self.added_range_transitions, \
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self.removed_range_transitions, \
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self.modified_range_transitions = self._diff_mls_rules(
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self._expand_generator(self._left_range_transitions, MLSRuleWrapper),
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self._expand_generator(self._right_range_transitions, MLSRuleWrapper))
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#
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# Internal functions
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#
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def _create_mls_rule_lists(self):
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"""Create rule lists for both policies."""
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self._left_range_transitions = []
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for rule in self.left_policy.mlsrules():
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# do not expand yet, to keep memory
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# use down as long as possible
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if rule.ruletype == "range_transition":
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self._left_range_transitions.append(rule)
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else:
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raise TypeError("Unknown rule type: {0}".format(rule.ruletype))
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self._right_range_transitions = []
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for rule in self.right_policy.mlsrules():
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# do not expand yet, to keep memory
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# use down as long as possible
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if rule.ruletype == "range_transition":
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self._right_range_transitions.append(rule)
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else:
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raise TypeError("Unknown rule type: {0}".format(rule.ruletype))
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def _diff_mls_rules(self, left_list, right_list):
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"""Common method for comparing type_* rules."""
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added, removed, matched = self._set_diff(left_list, right_list)
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modified = []
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for left_rule, right_rule in matched:
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# Criteria for modified rules
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# 1. change to default range
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if RangeWrapper(left_rule.default) != RangeWrapper(right_rule.default):
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modified.append(modified_mlsrule_record(left_rule,
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right_rule.default,
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left_rule.default))
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return added, removed, modified
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def _reset_diff(self):
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"""Reset diff results on policy changes."""
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self.log.debug("Resetting MLS rule differences")
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self.added_range_transitions = None
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self.removed_range_transitions = None
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self.modified_range_transitions = None
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# Sets of rules for each policy
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self._left_range_transitions = None
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self._right_range_transitions = None
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class MLSRuleWrapper(Wrapper):
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"""Wrap MLS rules to allow set operations."""
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def __init__(self, rule):
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self.origin = rule
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self.ruletype = rule.ruletype
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self.source = SymbolWrapper(rule.source)
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self.target = SymbolWrapper(rule.target)
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self.tclass = SymbolWrapper(rule.tclass)
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self.key = hash(rule)
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def __hash__(self):
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return self.key
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def __lt__(self, other):
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return self.key < other.key
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def __eq__(self, other):
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# because MLSRuleDifference groups rules by ruletype,
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# the ruletype always matches.
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return self.source == other.source and \
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self.target == other.target and \
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self.tclass == other.tclass
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