# Copyright 2014-2015, Tresys Technology, LLC
#
# SPDX-License-Identifier: LGPL-2.1-only
#
import logging
from typing import cast, Iterable, Optional, Set, Tuple
from . import mixins, query
from .descriptors import CriteriaDescriptor, CriteriaSetDescriptor
from .exception import RuleUseError, RuleNotConditional
from .policyrep import AnyTERule, AVRuleXperm, IoctlSet, TERuletype
from .util import match_indirect_regex, match_regex_or_set
class TERuleQuery(mixins.MatchObjClass, mixins.MatchPermission, query.PolicyQuery):
"""
Query the Type Enforcement 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_indirect If true, members of an attribute will be
matched rather than the attribute itself.
Default is true.
source_regex If true, regular expression matching will
be used on the source type/attribute.
Obeys the source_indirect option.
Default is false.
target The name of the target type/attribute to match.
target_indirect If true, members of an attribute will be
matched rather than the attribute itself.
Default is true.
target_regex If true, regular expression matching will
be used on the target type/attribute.
Obeys target_indirect option.
Default is false.
tclass The object class(es) to match.
tclass_regex If true, use a regular expression for
matching the rule's object class.
Default is false.
perms The set of permission(s) to match.
perms_equal If true, the permission set of the rule
must exactly match the permissions
criteria. If false, any set intersection
will match.
Default is false.
perms_regex If true, regular expression matching will be used
on the permission names instead of set logic.
Default is false.
perms_subset If true, the rule matches if the permissions criteria
is a subset of the rule's permission set.
Default is false.
default The name of the default type to match.
default_regex If true, regular expression matching will be
used on the default type.
Default is false.
boolean The set of boolean(s) to match.
boolean_regex If true, regular expression matching will be
used on the booleans.
Default is false.
boolean_equal If true, the booleans in the conditional
expression of the rule must exactly match the
criteria. If false, any set intersection
will match. Default is false.
"""
ruletype = CriteriaSetDescriptor(enum_class=TERuletype)
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
default = CriteriaDescriptor("default_regex", "lookup_type_or_attr")
default_regex: bool = False
boolean = CriteriaSetDescriptor("boolean_regex", "lookup_boolean")
boolean_regex: bool = False
boolean_equal: bool = False
_xperms: Optional[IoctlSet] = None
xperms_equal: bool = False
@property
def xperms(self) -> Optional[IoctlSet]:
return self._xperms
@xperms.setter
def xperms(self, value: Optional[Iterable[Tuple[int, int]]]) -> None:
if value:
pending_xperms: Set[int] = set()
for low, high in value:
if not (0 <= low <= 0xffff):
raise ValueError("{0:#07x} is not a valid ioctl.".format(low))
if not (0 <= high <= 0xffff):
raise ValueError("{0:#07x} is not a valid ioctl.".format(high))
if high < low:
high, low = low, high
pending_xperms.update(i for i in range(low, high + 1))
self._xperms = IoctlSet(pending_xperms)
else:
self._xperms = None
def __init__(self, policy, **kwargs) -> None:
super(TERuleQuery, self).__init__(policy, **kwargs)
self.log = logging.getLogger(__name__)
def results(self) -> Iterable[AnyTERule]:
"""Generator which yields all matching TE rules."""
self.log.info("Generating TE 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._match_perms_debug(self.log)
self.log.debug("Xperms: {0.xperms!r}, eq: {0.xperms_equal}".format(self))
self.log.debug("Default: {0.default!r}, regex: {0.default_regex}".format(self))
self.log.debug("Boolean: {0.boolean!r}, eq: {0.boolean_equal}, "
"regex: {0.boolean_regex}".format(self))
for rule in self.policy.terules():
#
# 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 permission set
#
try:
if self.perms and rule.extended:
if self.perms_equal and len(self.perms) > 1:
# if criteria is more than one standard permission,
# extended perm rules can never match if the
# permission set equality option is on.
continue
if cast(AVRuleXperm, rule).xperm_type not in self.perms:
continue
elif not self._match_perms(rule):
continue
except RuleUseError:
continue
#
# Matching on extended permissions
#
try:
if self.xperms and not match_regex_or_set(
rule.perms,
self.xperms,
self.xperms_equal,
False):
continue
except RuleUseError:
continue
#
# Matching on default type
#
if self.default:
try:
# because default type is always a single
# type, hard-code indirect to True
# so the criteria can be an attribute
if not match_indirect_regex(
rule.default,
self.default,
True,
self.default_regex):
continue
except RuleUseError:
continue
#
# Match on Boolean in conditional expression
#
if self.boolean:
try:
if not match_regex_or_set(
rule.conditional.booleans,
self.boolean,
self.boolean_equal,
self.boolean_regex):
continue
except RuleNotConditional:
continue
# if we get here, we have matched all available criteria
yield rule
