//=== FixedAddressChecker.cpp - Fixed address usage checker ----*- C++ -*--===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

// This files defines FixedAddressChecker, a builtin checker that checks for

// assignment of a fixed address to a pointer.

// This check corresponds to CWE-587.

//

//===----------------------------------------------------------------------===//

#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"

#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"

#include "clang/StaticAnalyzer/Core/Checker.h"

#include "clang/StaticAnalyzer/Core/CheckerManager.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"

using namespace clang;

using namespace ento;

namespace {

class FixedAddressChecker

  : public Checker< check::PreStmt<BinaryOperator> > {

  mutable std::unique_ptr<BugType> BT;

public:

  void checkPreStmt(const BinaryOperator *B, CheckerContext &C) const;

};

}

void FixedAddressChecker::checkPreStmt(const BinaryOperator *B,

                                       CheckerContext &C) const {

  // Using a fixed address is not portable because that address will probably

  // not be valid in all environments or platforms.

  if (B->getOpcode() != BO_Assign)

    return;

  QualType T = B->getType();

  if (!T->isPointerType())

    return;

  SVal RV = C.getSVal(B->getRHS());

  if (!RV.isConstant() || 
RV.isZeroConstant()23
)

    return;

  if (ExplodedNode *N = C.generateNonFatalErrorNode()) {

    // FIXME: improve grammar in the following strings:

    if (!BT)

      BT.reset(new BugType(this, "Use fixed address"));

    constexpr llvm::StringLiteral Msg =

        "Using a fixed address is not portable because that address will "

        "probably not be valid in all environments or platforms.";

    auto R = std::make_unique<PathSensitiveBugReport>(*BT, Msg, N);

    R->addRange(B->getRHS()->getSourceRange());

    C.emitReport(std::move(R));

  }

}

void ento::registerFixedAddressChecker(CheckerManager &mgr) {

  mgr.registerChecker<FixedAddressChecker>();

}

bool ento::shouldRegisterFixedAddressChecker(const CheckerManager &mgr) {

  return true;

}