1 # Copyright 2014, Tresys Technology, LLC 2 # 3 # This file is part of SETools. 4 # 5 # SETools is free software: you can redistribute it and/or modify 6 # it under the terms of the GNU Lesser General Public License as 7 # published by the Free Software Foundation, either version 2.1 of 8 # the License, or (at your option) any later version. 9 # 10 # SETools is distributed in the hope that it will be useful, 11 # but WITHOUT ANY WARRANTY; without even the implied warranty of 12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 # GNU Lesser General Public License for more details. 14 # 15 # You should have received a copy of the GNU Lesser General Public 16 # License along with SETools. If not, see 17 # <http://www.gnu.org/licenses/>. 18 # 19 from . import exception 20 from . import qpol 21 from . import rule 22 from . import typeattr 23 from . import mls 24 25 26 def mls_rule_factory(policy, symbol): 27 """Factory function for creating MLS rule objects.""" 28 if not isinstance(symbol, qpol.qpol_range_trans_t): 29 raise TypeError("MLS rules cannot be looked-up.") 30 31 return MLSRule(policy, symbol) 32 33 34 def validate_ruletype(types): 35 """Validate MLS rule types.""" 36 for t in types: 37 if t not in ["range_transition"]: 38 raise exception.InvalidMLSRuleType("{0} is not a valid MLS rule type.".format(t)) 39 40 41 class MLSRule(rule.PolicyRule): 42 43 """An MLS rule.""" 44 45 def __str__(self): 46 # TODO: If we ever get more MLS rules, fix this format. 47 return "range_transition {0.source} {0.target}:{0.tclass} {0.default};".format(self) 48 49 @property 50 def source(self): 51 """The rule's source type/attribute.""" 52 return typeattr.type_or_attr_factory(self.policy, self.qpol_symbol.source_type(self.policy)) 53 54 @property 55 def target(self): 56 """The rule's target type/attribute.""" 57 return typeattr.type_or_attr_factory(self.policy, self.qpol_symbol.target_type(self.policy)) 58 59 @property 60 def default(self): 61 """The rule's default range.""" 62 return mls.range_factory(self.policy, self.qpol_symbol.range(self.policy)) 63
