107 lines · cpp
1//== BoolAssignmentChecker.cpp - Boolean assignment checker -----*- C++ -*--==//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// This defines BoolAssignmentChecker, a builtin check in ExprEngine that10// performs checks for assignment of non-Boolean values to Boolean variables.11//12//===----------------------------------------------------------------------===//13 14#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"15#include "clang/StaticAnalyzer/Checkers/Taint.h"16#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"17#include "clang/StaticAnalyzer/Core/Checker.h"18#include "clang/StaticAnalyzer/Core/CheckerManager.h"19#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"20#include <optional>21 22using namespace clang;23using namespace ento;24 25namespace {26class BoolAssignmentChecker : public Checker<check::Bind> {27 const BugType BT{this, "Assignment of a non-Boolean value"};28 void emitReport(ProgramStateRef State, CheckerContext &C,29 bool IsTainted = false) const;30 31public:32 void checkBind(SVal Loc, SVal Val, const Stmt *S, bool AtDeclInit,33 CheckerContext &C) const;34};35} // end anonymous namespace36 37void BoolAssignmentChecker::emitReport(ProgramStateRef State, CheckerContext &C,38 bool IsTainted) const {39 if (ExplodedNode *N = C.generateNonFatalErrorNode(State)) {40 StringRef Msg = IsTainted ? "Might assign a tainted non-Boolean value"41 : "Assignment of a non-Boolean value";42 C.emitReport(std::make_unique<PathSensitiveBugReport>(BT, Msg, N));43 }44}45 46static bool isBooleanType(QualType Ty) {47 if (Ty->isBooleanType()) // C++ or C9948 return true;49 50 if (const TypedefType *TT = Ty->getAs<TypedefType>())51 return TT->getDecl()->getName() == "BOOL" || // Objective-C52 TT->getDecl()->getName() == "_Bool" || // stdbool.h < C9953 TT->getDecl()->getName() == "Boolean"; // MacTypes.h54 55 return false;56}57 58void BoolAssignmentChecker::checkBind(SVal Loc, SVal Val, const Stmt *S,59 bool AtDeclInit,60 CheckerContext &C) const {61 62 // We are only interested in stores into Booleans.63 const TypedValueRegion *TR =64 dyn_cast_or_null<TypedValueRegion>(Loc.getAsRegion());65 66 if (!TR)67 return;68 69 QualType RegTy = TR->getValueType();70 71 if (!isBooleanType(RegTy))72 return;73 74 // Get the value of the right-hand side. We only care about values75 // that are defined (UnknownVals and UndefinedVals are handled by other76 // checkers).77 std::optional<NonLoc> NV = Val.getAs<NonLoc>();78 if (!NV)79 return;80 81 // Check if the assigned value meets our criteria for correctness. It must82 // be a value that is either 0 or 1. One way to check this is to see if83 // the value is possibly < 0 (for a negative value) or greater than 1.84 ProgramStateRef State = C.getState();85 BasicValueFactory &BVF = C.getSValBuilder().getBasicValueFactory();86 ConstraintManager &CM = C.getConstraintManager();87 88 llvm::APSInt Zero = BVF.getValue(0, RegTy);89 llvm::APSInt One = BVF.getValue(1, RegTy);90 91 ProgramStateRef StIn, StOut;92 std::tie(StIn, StOut) = CM.assumeInclusiveRangeDual(State, *NV, Zero, One);93 94 if (!StIn)95 emitReport(StOut, C);96 if (StIn && StOut && taint::isTainted(State, *NV))97 emitReport(StOut, C, /*IsTainted=*/true);98}99 100void ento::registerBoolAssignmentChecker(CheckerManager &Mgr) {101 Mgr.registerChecker<BoolAssignmentChecker>();102}103 104bool ento::shouldRegisterBoolAssignmentChecker(const CheckerManager &Mgr) {105 return true;106}107