| # Copyright 2014, 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/>. |
| # |
| from . import exception |
| from . import qpol |
| from . import symbol |
| |
| |
| def _symbol_lookup(qpol_policy, name): |
| """Look up the low-level qpol policy reference""" |
| if isinstance(name, qpol.qpol_type_t): |
| return name |
| |
| try: |
| return qpol.qpol_type_t(qpol_policy, str(name)) |
| except ValueError: |
| raise exception.InvalidType("{0} is not a valid type/attribute".format(name)) |
| |
| |
| def attribute_factory(qpol_policy, name): |
| """Factory function for creating attribute objects.""" |
| |
| if isinstance(name, TypeAttribute): |
| assert name.policy == qpol_policy |
| return name |
| |
| qpol_symbol = _symbol_lookup(qpol_policy, name) |
| |
| if not qpol_symbol.isattr(qpol_policy): |
| raise TypeError("{0} is a type".format(qpol_symbol.name(qpol_policy))) |
| |
| return TypeAttribute(qpol_policy, qpol_symbol) |
| |
| |
| def type_factory(qpol_policy, name, deref=False): |
| """Factory function for creating type objects.""" |
| |
| if isinstance(name, Type): |
| assert name.policy == qpol_policy |
| return name |
| |
| qpol_symbol = _symbol_lookup(qpol_policy, name) |
| |
| if qpol_symbol.isattr(qpol_policy): |
| raise TypeError("{0} is an attribute".format(qpol_symbol.name(qpol_policy))) |
| elif qpol_symbol.isalias(qpol_policy) and not deref: |
| raise TypeError("{0} is an alias.".format(qpol_symbol.name(qpol_policy))) |
| |
| return Type(qpol_policy, qpol_symbol) |
| |
| |
| def type_or_attr_factory(qpol_policy, name, deref=False): |
| """Factory function for creating type or attribute objects.""" |
| |
| if isinstance(name, (Type, TypeAttribute)): |
| assert name.policy == qpol_policy |
| return name |
| |
| qpol_symbol = _symbol_lookup(qpol_policy, name) |
| |
| if qpol_symbol.isalias(qpol_policy) and not deref: |
| raise TypeError("{0} is an alias.".format(qpol_symbol.name(qpol_policy))) |
| |
| if qpol_symbol.isattr(qpol_policy): |
| return TypeAttribute(qpol_policy, qpol_symbol) |
| else: |
| return Type(qpol_policy, qpol_symbol) |
| |
| |
| class BaseType(symbol.PolicySymbol): |
| |
| """Type/attribute base class.""" |
| |
| @property |
| def ispermissive(self): |
| raise NotImplementedError |
| |
| def expand(self): |
| """Generator that expands this attribute into its member types.""" |
| raise NotImplementedError |
| |
| def attributes(self): |
| """Generator that yields all attributes for this type.""" |
| raise NotImplementedError |
| |
| def aliases(self): |
| """Generator that yields all aliases for this type.""" |
| raise NotImplementedError |
| |
| |
| class Type(BaseType): |
| |
| """A type.""" |
| |
| @property |
| def ispermissive(self): |
| """(T/F) the type is permissive.""" |
| return self.qpol_symbol.ispermissive(self.policy) |
| |
| def expand(self): |
| """Generator that expands this into its member types.""" |
| yield self |
| |
| def attributes(self): |
| """Generator that yields all attributes for this type.""" |
| for attr in self.qpol_symbol.attr_iter(self.policy): |
| yield attribute_factory(self.policy, attr) |
| |
| def aliases(self): |
| """Generator that yields all aliases for this type.""" |
| for alias in self.qpol_symbol.alias_iter(self.policy): |
| yield alias |
| |
| def statement(self): |
| attrs = list(self.attributes()) |
| aliases = list(self.aliases()) |
| stmt = "type {0}".format(self) |
| if aliases: |
| if len(aliases) > 1: |
| stmt += " alias {{ {0} }}".format(' '.join(aliases)) |
| else: |
| stmt += " alias {0}".format(aliases[0]) |
| for attr in attrs: |
| stmt += ", {0}".format(attr) |
| stmt += ";" |
| return stmt |
| |
| |
| class TypeAttribute(BaseType): |
| |
| """An attribute.""" |
| |
| def __contains__(self, other): |
| for type_ in self.expand(): |
| if other == type_: |
| return True |
| |
| return False |
| |
| def expand(self): |
| """Generator that expands this attribute into its member types.""" |
| for type_ in self.qpol_symbol.type_iter(self.policy): |
| yield type_factory(self.policy, type_) |
| |
| def attributes(self): |
| """Generator that yields all attributes for this type.""" |
| raise exception.SymbolUseError("{0} is an attribute, thus does not have attributes.". |
| format(self)) |
| |
| def aliases(self): |
| """Generator that yields all aliases for this type.""" |
| raise exception.SymbolUseError("{0} is an attribute, thus does not have aliases.". |
| format(self)) |
| |
| @property |
| def ispermissive(self): |
| """(T/F) the type is permissive.""" |
| raise exception.SymbolUseError("{0} is an attribute, thus cannot be permissive.". |
| format(self)) |
| |
| def statement(self): |
| return "attribute {0};".format(self) |