69 lines
2.3 KiB
C++
69 lines
2.3 KiB
C++
//=== PointerArithChecker.cpp - Pointer arithmetic checker -----*- C++ -*--===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This files defines PointerArithChecker, a builtin checker that checks for
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// pointer arithmetic on locations other than array elements.
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//
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//===----------------------------------------------------------------------===//
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#include "ClangSACheckers.h"
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#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
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#include "clang/StaticAnalyzer/Core/Checker.h"
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#include "clang/StaticAnalyzer/Core/CheckerManager.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
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using namespace clang;
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using namespace ento;
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namespace {
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class PointerArithChecker
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: public Checker< check::PreStmt<BinaryOperator> > {
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mutable OwningPtr<BuiltinBug> BT;
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public:
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void checkPreStmt(const BinaryOperator *B, CheckerContext &C) const;
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};
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}
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void PointerArithChecker::checkPreStmt(const BinaryOperator *B,
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CheckerContext &C) const {
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if (B->getOpcode() != BO_Sub && B->getOpcode() != BO_Add)
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return;
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ProgramStateRef state = C.getState();
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const LocationContext *LCtx = C.getLocationContext();
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SVal LV = state->getSVal(B->getLHS(), LCtx);
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SVal RV = state->getSVal(B->getRHS(), LCtx);
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const MemRegion *LR = LV.getAsRegion();
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if (!LR || !RV.isConstant())
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return;
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// If pointer arithmetic is done on variables of non-array type, this often
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// means behavior rely on memory organization, which is dangerous.
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if (isa<VarRegion>(LR) || isa<CodeTextRegion>(LR) ||
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isa<CompoundLiteralRegion>(LR)) {
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if (ExplodedNode *N = C.addTransition()) {
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if (!BT)
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BT.reset(new BuiltinBug("Dangerous pointer arithmetic",
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"Pointer arithmetic done on non-array variables "
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"means reliance on memory layout, which is "
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"dangerous."));
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BugReport *R = new BugReport(*BT, BT->getDescription(), N);
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R->addRange(B->getSourceRange());
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C.emitReport(R);
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}
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}
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}
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void ento::registerPointerArithChecker(CheckerManager &mgr) {
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mgr.registerChecker<PointerArithChecker>();
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}
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