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# Copyright 2014-2015, Tresys Technology, LLC
#
# SPDX-License-Identifier: LGPL-2.1-only
#
from typing import Iterable
from .descriptors import CriteriaDescriptor, CriteriaSetDescriptor
from .mixins import MatchObjClass
from .policyrep import MLSRule, MLSRuletype
from .query import PolicyQuery
from .util import match_indirect_regex, match_range
class MLSRuleQuery(MatchObjClass, PolicyQuery):
"""
Query MLS rules.
Parameter:
policy The policy to query.
Keyword Parameters/Class attributes:
ruletype The list of rule type(s) to match.
source The name of the source type/attribute to match.
source_regex If true, regular expression matching will
be used on the source type/attribute.
target The name of the target type/attribute to match.
target_regex If true, regular expression matching will
be used on the target type/attribute.
tclass The object class(es) to match.
tclass_regex If true, use a regular expression for
matching the rule's object class.
"""
ruletype = CriteriaSetDescriptor(enum_class=MLSRuletype)
source = CriteriaDescriptor("source_regex", "lookup_type_or_attr")
source_regex: bool = False
source_indirect: bool = True
target = CriteriaDescriptor("target_regex", "lookup_type_or_attr")
target_regex: bool = False
target_indirect: bool = True
tclass = CriteriaSetDescriptor("tclass_regex", "lookup_class")
tclass_regex: bool = False
default = CriteriaDescriptor(lookup_function="lookup_range")
default_overlap: bool = False
default_subset: bool = False
default_superset: bool = False
default_proper: bool = False
def results(self) -> Iterable[MLSRule]:
"""Generator which yields all matching MLS rules."""
self.log.info("Generating MLS rule results from {0.policy}".format(self))
self.log.debug("Ruletypes: {0.ruletype}".format(self))
self.log.debug("Source: {0.source!r}, indirect: {0.source_indirect}, "
"regex: {0.source_regex}".format(self))
self.log.debug("Target: {0.target!r}, indirect: {0.target_indirect}, "
"regex: {0.target_regex}".format(self))
self._match_object_class_debug(self.log)
self.log.debug("Default: {0.default!r}, overlap: {0.default_overlap}, "
"subset: {0.default_subset}, superset: {0.default_superset}, "
"proper: {0.default_proper}".format(self))
for rule in self.policy.mlsrules():
#
# Matching on rule type
#
if self.ruletype:
if rule.ruletype not in self.ruletype:
continue
#
# Matching on source type
#
if self.source and not match_indirect_regex(
rule.source,
self.source,
self.source_indirect,
self.source_regex):
continue
#
# Matching on target type
#
if self.target and not match_indirect_regex(
rule.target,
self.target,
self.target_indirect,
self.target_regex):
continue
#
# Matching on object class
#
if not self._match_object_class(rule):
continue
#
# Matching on range
#
if self.default and not match_range(
rule.default,
self.default,
self.default_subset,
self.default_overlap,
self.default_superset,
self.default_proper):
continue
# if we get here, we have matched all available criteria
yield rule
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