| //=== PointerArithChecker.cpp - Pointer arithmetic 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 PointerArithChecker, a builtin checker that checks for |
| // pointer arithmetic on locations other than array elements. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #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 PointerArithChecker |
| : public Checker< check::PreStmt<BinaryOperator> > { |
| mutable llvm::OwningPtr<BuiltinBug> BT; |
| |
| public: |
| void checkPreStmt(const BinaryOperator *B, CheckerContext &C) const; |
| }; |
| } |
| |
| void PointerArithChecker::checkPreStmt(const BinaryOperator *B, |
| CheckerContext &C) const { |
| if (B->getOpcode() != BO_Sub && B->getOpcode() != BO_Add) |
| return; |
| |
| const ProgramState *state = C.getState(); |
| SVal LV = state->getSVal(B->getLHS()); |
| SVal RV = state->getSVal(B->getRHS()); |
| |
| const MemRegion *LR = LV.getAsRegion(); |
| |
| if (!LR || !RV.isConstant()) |
| return; |
| |
| // If pointer arithmetic is done on variables of non-array type, this often |
| // means behavior rely on memory organization, which is dangerous. |
| if (isa<VarRegion>(LR) || isa<CodeTextRegion>(LR) || |
| isa<CompoundLiteralRegion>(LR)) { |
| |
| if (ExplodedNode *N = C.generateNode()) { |
| if (!BT) |
| BT.reset(new BuiltinBug("Dangerous pointer arithmetic", |
| "Pointer arithmetic done on non-array variables " |
| "means reliance on memory layout, which is " |
| "dangerous.")); |
| RangedBugReport *R = new RangedBugReport(*BT, BT->getDescription(), N); |
| R->addRange(B->getSourceRange()); |
| C.EmitReport(R); |
| } |
| } |
| } |
| |
| void ento::registerPointerArithChecker(CheckerManager &mgr) { |
| mgr.registerChecker<PointerArithChecker>(); |
| } |