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author | Carlo Zancanaro <carlo@pc-4w14-0.cs.usyd.edu.au> | 2012-10-15 17:10:06 +1100 |
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committer | Carlo Zancanaro <carlo@pc-4w14-0.cs.usyd.edu.au> | 2012-10-15 17:10:06 +1100 |
commit | be1de4be954c80875ad4108e0a33e8e131b2f2c0 (patch) | |
tree | 1fbbecf276bf7c7bdcbb4dd446099d6d90eaa516 /clang/lib/StaticAnalyzer/Checkers/PointerSubChecker.cpp | |
parent | c4626a62754862d20b41e8a46a3574264ea80e6d (diff) | |
parent | f1bd2e48c5324d3f7cda4090c87f8a5b6f463ce2 (diff) |
Merge branch 'master' of ssh://bitbucket.org/czan/honours
Diffstat (limited to 'clang/lib/StaticAnalyzer/Checkers/PointerSubChecker.cpp')
-rw-r--r-- | clang/lib/StaticAnalyzer/Checkers/PointerSubChecker.cpp | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/clang/lib/StaticAnalyzer/Checkers/PointerSubChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/PointerSubChecker.cpp new file mode 100644 index 0000000..fa5c6a3 --- /dev/null +++ b/clang/lib/StaticAnalyzer/Checkers/PointerSubChecker.cpp @@ -0,0 +1,76 @@ +//=== 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/Checker.h" +#include "clang/StaticAnalyzer/Core/CheckerManager.h" +#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" +#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" + +using namespace clang; +using namespace ento; + +namespace { +class PointerSubChecker + : public Checker< check::PreStmt<BinaryOperator> > { + mutable OwningPtr<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("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>(); +} |