forked from OSchip/llvm-project
73 lines
2.3 KiB
C++
73 lines
2.3 KiB
C++
//=== PointerSubChecker.cpp - Pointer subtraction 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 PointerSubChecker, a builtin checker that checks for
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// pointer subtractions on two pointers pointing to different memory chunks.
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// This check corresponds to CWE-469.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Analysis/PathSensitive/CheckerVisitor.h"
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#include "GRExprEngineInternalChecks.h"
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using namespace clang;
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namespace {
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class VISIBILITY_HIDDEN PointerSubChecker
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: public CheckerVisitor<PointerSubChecker> {
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BuiltinBug *BT;
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public:
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PointerSubChecker() : BT(0) {}
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static void *getTag();
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void PreVisitBinaryOperator(CheckerContext &C, const BinaryOperator *B);
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};
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}
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void *PointerSubChecker::getTag() {
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static int x;
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return &x;
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}
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void PointerSubChecker::PreVisitBinaryOperator(CheckerContext &C,
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const BinaryOperator *B) {
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// When doing pointer subtraction, if the two pointers do not point to the
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// same memory chunk, emit a warning.
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if (B->getOpcode() != BinaryOperator::Sub)
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return;
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const GRState *state = C.getState();
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SVal LV = state->getSVal(B->getLHS());
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SVal RV = state->getSVal(B->getRHS());
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const MemRegion *LR = LV.getAsRegion();
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const MemRegion *RR = RV.getAsRegion();
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if (!(LR && RR) || (LR == RR))
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return;
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// We don't reason about SymbolicRegions for now.
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if (isa<SymbolicRegion>(LR) || isa<SymbolicRegion>(RR))
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return;
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if (ExplodedNode *N = C.GenerateNode(B)) {
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if (!BT)
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BT = new BuiltinBug("Pointer subtraction",
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"Subtraction of two pointers that do not point to "
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"the same memory chunk may cause incorrect result.");
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RangedBugReport *R = new RangedBugReport(*BT, BT->getDescription().c_str(),
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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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void clang::RegisterPointerSubChecker(GRExprEngine &Eng) {
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Eng.registerCheck(new PointerSubChecker());
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}
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