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# Copyright 2015, Tresys Technology, LLC
#
# 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/>.
#
import logging
import re
from .descriptors import CriteriaDescriptor, CriteriaSetDescriptor
from .exception import ConstraintUseError
from .mixins import MatchObjClass, MatchPermission
from .policyrep import ConstraintRuletype
from .query import PolicyQuery
from .util import match_in_set
class ConstraintQuery(MatchObjClass, MatchPermission, PolicyQuery):
"""
Query constraint rules, (mls)constrain/(mls)validatetrans.
Parameter:
policy The policy to query.
Keyword Parameters/Class attributes:
ruletype The list of rule type(s) to match.
tclass The object class(es) to match.
tclass_regex If true, use a regular expression for
matching the rule's object class.
perms The 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.
perms_regex If true, regular expression matching will be used
on the permission names instead of set logic.
role The name of the role to match in the
constraint expression.
role_indirect If true, members of an attribute will be
matched rather than the attribute itself.
role_regex If true, regular expression matching will
be used on the role.
type_ The name of the type/attribute to match in the
constraint expression.
type_indirect If true, members of an attribute will be
matched rather than the attribute itself.
type_regex If true, regular expression matching will
be used on the type/attribute.
user The name of the user to match in the
constraint expression.
user_regex If true, regular expression matching will
be used on the user.
"""
ruletype = CriteriaSetDescriptor(enum_class=ConstraintRuletype)
user = CriteriaDescriptor("user_regex", "lookup_user")
user_regex = False
role = CriteriaDescriptor("role_regex", "lookup_role")
role_regex = False
role_indirect = True
type_ = CriteriaDescriptor("type_regex", "lookup_type_or_attr")
type_regex = False
type_indirect = True
def __init__(self, policy, **kwargs):
super(ConstraintQuery, self).__init__(policy, **kwargs)
self.log = logging.getLogger(__name__)
def _match_expr(self, expr, criteria, indirect, regex):
"""
Match roles/types/users in a constraint expression,
optionally by expanding the contents of attributes.
Parameters:
expr The expression to match.
criteria The criteria to match.
indirect If attributes in the expression should be expanded.
regex If regular expression matching should be used.
"""
if indirect:
obj = set()
for item in expr:
obj.update(item.expand())
else:
obj = expr
return match_in_set(obj, criteria, regex)
def results(self):
"""Generator which yields all matching constraints rules."""
self.log.info("Generating constraint results from {0.policy}".format(self))
self.log.debug("Ruletypes: {0.ruletype}".format(self))
self._match_object_class_debug(self.log)
self._match_perms_debug(self.log)
self.log.debug("User: {0.user!r}, regex: {0.user_regex}".format(self))
self.log.debug("Role: {0.role!r}, regex: {0.role_regex}".format(self))
self.log.debug("Type: {0.type_!r}, regex: {0.type_regex}".format(self))
for c in self.policy.constraints():
if self.ruletype:
if c.ruletype not in self.ruletype:
continue
if not self._match_object_class(c):
continue
try:
if not self._match_perms(c):
continue
except ConstraintUseError:
continue
if self.role and not self._match_expr(
c.expression.roles,
self.role,
self.role_indirect,
self.role_regex):
continue
if self.type_ and not self._match_expr(
c.expression.types,
self.type_,
self.type_indirect,
self.type_regex):
continue
if self.user and not self._match_expr(
c.expression.users,
self.user,
False,
self.user_regex):
continue
yield c