1# Copyright 2015, 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# 19from collections import namedtuple 20 21from .descriptors import DiffResultDescriptor 22from .difference import Difference, SymbolWrapper 23 24 25modified_types_record = namedtuple("modified_type", ["added_attributes", 26 "removed_attributes", 27 "matched_attributes", 28 "modified_permissive", 29 "permissive", 30 "added_aliases", 31 "removed_aliases", 32 "matched_aliases"]) 33 34 35class TypesDifference(Difference): 36 37 """Determine the difference in types between two policies.""" 38 39 added_types = DiffResultDescriptor("diff_types") 40 removed_types = DiffResultDescriptor("diff_types") 41 modified_types = DiffResultDescriptor("diff_types") 42 43 def diff_types(self): 44 """Generate the difference in types between the policies.""" 45 46 self.log.info( 47 "Generating type differences from {0.left_policy} to {0.right_policy}".format(self)) 48 49 self.added_types, self.removed_types, matched_types = self._set_diff( 50 (SymbolWrapper(t) for t in self.left_policy.types()), 51 (SymbolWrapper(t) for t in self.right_policy.types())) 52 53 self.modified_types = dict() 54 55 for left_type, right_type in matched_types: 56 # Criteria for modified types 57 # 1. change to attribute set, or 58 # 2. change to alias set, or 59 # 3. different permissive setting 60 added_attr, removed_attr, matched_attr = self._set_diff( 61 (SymbolWrapper(a) for a in left_type.attributes()), 62 (SymbolWrapper(a) for a in right_type.attributes())) 63 64 added_aliases, removed_aliases, matched_aliases = self._set_diff(left_type.aliases(), 65 right_type.aliases()) 66 67 left_permissive = left_type.ispermissive 68 right_permissive = right_type.ispermissive 69 mod_permissive = left_permissive != right_permissive 70 71 if added_attr or removed_attr or added_aliases or removed_aliases or mod_permissive: 72 self.modified_types[left_type] = modified_types_record(added_attr, 73 removed_attr, 74 matched_attr, 75 mod_permissive, 76 left_permissive, 77 added_aliases, 78 removed_aliases, 79 matched_aliases) 80 81 # 82 # Internal functions 83 # 84 def _reset_diff(self): 85 """Reset diff results on policy changes.""" 86 self.log.debug("Resetting type differences") 87 self.added_types = None 88 self.removed_types = None 89 self.modified_types = None 90