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//=== CastToStructChecker.cpp - Fixed address usage 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 CastToStructChecker, a builtin checker that checks for
// cast from non-struct pointer to struct pointer.
// This check corresponds to CWE-588.
//
//===----------------------------------------------------------------------===//
#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 CastToStructChecker : public Checker< check::PreStmt<CastExpr> > {
mutable OwningPtr<BuiltinBug> BT;
public:
void checkPreStmt(const CastExpr *CE, CheckerContext &C) const;
};
}
void CastToStructChecker::checkPreStmt(const CastExpr *CE,
CheckerContext &C) const {
const Expr *E = CE->getSubExpr();
ASTContext &Ctx = C.getASTContext();
QualType OrigTy = Ctx.getCanonicalType(E->getType());
QualType ToTy = Ctx.getCanonicalType(CE->getType());
const PointerType *OrigPTy = dyn_cast<PointerType>(OrigTy.getTypePtr());
const PointerType *ToPTy = dyn_cast<PointerType>(ToTy.getTypePtr());
if (!ToPTy || !OrigPTy)
return;
QualType OrigPointeeTy = OrigPTy->getPointeeType();
QualType ToPointeeTy = ToPTy->getPointeeType();
if (!ToPointeeTy->isStructureOrClassType())
return;
// We allow cast from void*.
if (OrigPointeeTy->isVoidType())
return;
// Now the cast-to-type is struct pointer, the original type is not void*.
if (!OrigPointeeTy->isRecordType()) {
if (ExplodedNode *N = C.addTransition()) {
if (!BT)
BT.reset(new BuiltinBug("Cast from non-struct type to struct type",
"Casting a non-structure type to a structure type "
"and accessing a field can lead to memory access "
"errors or data corruption."));
BugReport *R = new BugReport(*BT,BT->getDescription(), N);
R->addRange(CE->getSourceRange());
C.EmitReport(R);
}
}
}
void ento::registerCastToStructChecker(CheckerManager &mgr) {
mgr.registerChecker<CastToStructChecker>();
}
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