forked from OSchip/llvm-project
78 lines
2.5 KiB
C++
78 lines
2.5 KiB
C++
//=== PointerSubChecker.cpp - Pointer subtraction checker ------*- C++ -*--===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This files defines PointerSubChecker, a builtin checker that checks for
|
|
// pointer subtractions on two pointers pointing to different memory chunks.
|
|
// This check corresponds to CWE-469.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "ClangSACheckers.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 PointerSubChecker
|
|
: public Checker< check::PreStmt<BinaryOperator> > {
|
|
mutable std::unique_ptr<BuiltinBug> BT;
|
|
|
|
public:
|
|
void checkPreStmt(const BinaryOperator *B, CheckerContext &C) const;
|
|
};
|
|
}
|
|
|
|
void PointerSubChecker::checkPreStmt(const BinaryOperator *B,
|
|
CheckerContext &C) const {
|
|
// When doing pointer subtraction, if the two pointers do not point to the
|
|
// same memory chunk, emit a warning.
|
|
if (B->getOpcode() != BO_Sub)
|
|
return;
|
|
|
|
ProgramStateRef state = C.getState();
|
|
const LocationContext *LCtx = C.getLocationContext();
|
|
SVal LV = state->getSVal(B->getLHS(), LCtx);
|
|
SVal RV = state->getSVal(B->getRHS(), LCtx);
|
|
|
|
const MemRegion *LR = LV.getAsRegion();
|
|
const MemRegion *RR = RV.getAsRegion();
|
|
|
|
if (!(LR && RR))
|
|
return;
|
|
|
|
const MemRegion *BaseLR = LR->getBaseRegion();
|
|
const MemRegion *BaseRR = RR->getBaseRegion();
|
|
|
|
if (BaseLR == BaseRR)
|
|
return;
|
|
|
|
// Allow arithmetic on different symbolic regions.
|
|
if (isa<SymbolicRegion>(BaseLR) || isa<SymbolicRegion>(BaseRR))
|
|
return;
|
|
|
|
if (ExplodedNode *N = C.addTransition()) {
|
|
if (!BT)
|
|
BT.reset(
|
|
new BuiltinBug(this, "Pointer subtraction",
|
|
"Subtraction of two pointers that do not point to "
|
|
"the same memory chunk may cause incorrect result."));
|
|
BugReport *R = new BugReport(*BT, BT->getDescription(), N);
|
|
R->addRange(B->getSourceRange());
|
|
C.emitReport(R);
|
|
}
|
|
}
|
|
|
|
void ento::registerPointerSubChecker(CheckerManager &mgr) {
|
|
mgr.registerChecker<PointerSubChecker>();
|
|
}
|