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Editing: constraints.py
# Copyright 2016, Tresys Technology, LLC # Copyright 2018, Chris PeBenito <pebenito@ieee.org> # # SPDX-License-Identifier: LGPL-2.1-only # from collections import defaultdict from .. import policyrep from .descriptors import DiffResultDescriptor from .difference import Difference, SymbolWrapper, Wrapper from .objclass import class_wrapper_factory from .typing import RuleList class ConstraintsDifference(Difference): """ Determine the difference in constraints between two policies. Since the compiler does not union constraints, there may be multiple constraints with the same ruletype, object class, and permission set, so constraints can only be added or removed, not modified. The constraint expressions are compared only on a basic level. Expressions that are logically equivalent but are structurally different, for example, by associativity, will be considered different. Type and role attributes are also not expanded, so if there are changes to attribute members, it will not be reflected as a difference. """ def diff_constrains(self) -> None: """Generate the difference in constraint rules between the policies.""" self.log.info( f"Generating constraint differences from {self.left_policy} to {self.right_policy}") if self._left_constraints is None or self._right_constraints is None: self._create_constrain_lists() assert self._left_constraints is not None, "Left constraints didn't load, this a bug." assert self._right_constraints is not None, "Right constraints didn't load, this a bug." self.added_constrains, self.removed_constrains, _ = self._set_diff( (ConstraintWrapper(c) for c in self._left_constraints[ policyrep.ConstraintRuletype.constrain]), (ConstraintWrapper(c) for c in self._right_constraints[ policyrep.ConstraintRuletype.constrain])) def diff_mlsconstrains(self) -> None: """Generate the difference in MLS constraint rules between the policies.""" self.log.info( f"Generating MLS constraint differences from {self.left_policy} " f"to {self.right_policy}") if self._left_constraints is None or self._right_constraints is None: self._create_constrain_lists() assert self._left_constraints is not None, "Left constraints didn't load, this a bug." assert self._right_constraints is not None, "Right constraints didn't load, this a bug." self.added_mlsconstrains, self.removed_mlsconstrains, _ = self._set_diff( (ConstraintWrapper(c) for c in self._left_constraints[ policyrep.ConstraintRuletype.mlsconstrain]), (ConstraintWrapper(c) for c in self._right_constraints[ policyrep.ConstraintRuletype.mlsconstrain])) def diff_validatetrans(self) -> None: """Generate the difference in validatetrans rules between the policies.""" self.log.info( f"Generating validatetrans differences from {self.left_policy} to {self.right_policy}") if self._left_constraints is None or self._right_constraints is None: self._create_constrain_lists() assert self._left_constraints is not None, "Left constraints didn't load, this a bug." assert self._right_constraints is not None, "Right constraints didn't load, this a bug." self.added_validatetrans, self.removed_validatetrans, _ = self._set_diff( (ConstraintWrapper(c) for c in self._left_constraints[ policyrep.ConstraintRuletype.validatetrans]), (ConstraintWrapper(c) for c in self._right_constraints[ policyrep.ConstraintRuletype.validatetrans])) def diff_mlsvalidatetrans(self) -> None: """Generate the difference in MLS validatetrans rules between the policies.""" self.log.info( f"Generating mlsvalidatetrans differences from {self.left_policy} " f"to {self.right_policy}") if self._left_constraints is None or self._right_constraints is None: self._create_constrain_lists() assert self._left_constraints is not None, "Left constraints didn't load, this a bug." assert self._right_constraints is not None, "Right constraints didn't load, this a bug." self.added_mlsvalidatetrans, self.removed_mlsvalidatetrans, _ = self._set_diff( (ConstraintWrapper(c) for c in self._left_constraints[ policyrep.ConstraintRuletype.mlsvalidatetrans]), (ConstraintWrapper(c) for c in self._right_constraints[ policyrep.ConstraintRuletype.mlsvalidatetrans])) added_constrains = DiffResultDescriptor[policyrep.Constraint](diff_constrains) removed_constrains = DiffResultDescriptor[policyrep.Constraint](diff_constrains) added_mlsconstrains = DiffResultDescriptor[policyrep.Constraint](diff_mlsconstrains) removed_mlsconstrains = DiffResultDescriptor[policyrep.Constraint](diff_mlsconstrains) added_validatetrans = DiffResultDescriptor[policyrep.Validatetrans](diff_validatetrans) removed_validatetrans = DiffResultDescriptor[policyrep.Validatetrans](diff_validatetrans) added_mlsvalidatetrans = DiffResultDescriptor[policyrep.Validatetrans](diff_mlsvalidatetrans) removed_mlsvalidatetrans = DiffResultDescriptor[policyrep.Validatetrans](diff_mlsvalidatetrans) # Lists of rules for each policy _left_constraints: RuleList[policyrep.ConstraintRuletype, policyrep.AnyConstraint] = None _right_constraints: RuleList[policyrep.ConstraintRuletype, policyrep.AnyConstraint] = None # # Internal functions # def _create_constrain_lists(self) -> None: """Create rule lists for both policies.""" self._left_constraints = defaultdict(list) self.log.debug(f"Building constraint lists from {self.left_policy}") for rule in self.left_policy.constraints(): self._left_constraints[rule.ruletype].append(rule) for ruletype, rules in self._left_constraints.items(): self.log.debug(f"Loaded {len(rules)} {ruletype} rules.") self._right_constraints = defaultdict(list) self.log.debug(f"Building constraint lists from {self.right_policy}") for rule in self.right_policy.constraints(): self._right_constraints[rule.ruletype].append(rule) for ruletype, rules in self._right_constraints.items(): self.log.debug(f"Loaded {len(rules)} {ruletype} rules.") self.log.debug("Completed building constraint rule lists.") def _reset_diff(self) -> None: """Reset diff results on policy changes.""" self.log.debug("Resetting all constraints differences") del self.added_constrains del self.removed_constrains del self.added_mlsconstrains del self.removed_mlsconstrains del self.added_validatetrans del self.removed_validatetrans del self.added_mlsvalidatetrans del self.removed_mlsvalidatetrans # Sets of rules for each policy self._left_constraints = None self._right_constraints = None class ConstraintWrapper(Wrapper[policyrep.AnyConstraint]): """Wrap constraints for diff purposes.""" __slots__ = ("ruletype", "tclass", "perms", "expr") def __init__(self, rule: policyrep.AnyConstraint) -> None: self.origin = rule self.ruletype = rule.ruletype self.tclass = class_wrapper_factory(rule.tclass) self.perms: frozenset[str] | None try: self.perms = rule.perms except AttributeError: # (mls)validatetrans self.perms = None self.key = hash(rule) self.expr: list[frozenset[SymbolWrapper[policyrep.Role | policyrep.Type | policyrep.User]] | str] = [] for op in rule.expression: if isinstance(op, frozenset): # lists of types/users/roles self.expr.append(frozenset(SymbolWrapper(item) for item in op)) else: # strings in the expression such as u1/r1/t1 or "==" self.expr.append(op) def __hash__(self): return self.key def __lt__(self, other): return self.key < other.key def __eq__(self, other): return self.ruletype == other.ruletype and \ self.tclass == other.tclass and \ self.perms == other.perms and \ self.expr == other.expr
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