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//===- OSObjectCStyleCast.cpp ------------------------------------*- C++ -*-==//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines OSObjectCStyleCast checker, which checks for C-style casts
// of OSObjects. Such casts almost always indicate a code smell,
// as an explicit static or dynamic cast should be used instead.
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
#include "llvm/Support/Debug.h"
using namespace clang;
using namespace ento;
using namespace ast_matchers;
namespace {
const char *WarnAtNode = "OSObjCast";
class OSObjectCStyleCastChecker : public Checker<check::ASTCodeBody> {
public:
void checkASTCodeBody(const Decl *D,
AnalysisManager &AM,
BugReporter &BR) const;
};
static void emitDiagnostics(const BoundNodes &Nodes,
BugReporter &BR,
AnalysisDeclContext *ADC,
const OSObjectCStyleCastChecker *Checker) {
const auto *CE = Nodes.getNodeAs<CastExpr>(WarnAtNode);
assert(CE);
std::string Diagnostics;
llvm::raw_string_ostream OS(Diagnostics);
OS << "C-style cast of OSObject. Use OSDynamicCast instead.";
BR.EmitBasicReport(
ADC->getDecl(),
Checker,
/*Name=*/"OSObject C-Style Cast",
/*BugCategory=*/"Security",
OS.str(),
PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), ADC),
CE->getSourceRange());
}
static decltype(auto) hasTypePointingTo(DeclarationMatcher DeclM) {
return hasType(pointerType(pointee(hasDeclaration(DeclM))));
}
void OSObjectCStyleCastChecker::checkASTCodeBody(const Decl *D, AnalysisManager &AM,
BugReporter &BR) const {
AnalysisDeclContext *ADC = AM.getAnalysisDeclContext(D);
auto DynamicCastM = callExpr(callee(functionDecl(hasName("safeMetaCast"))));
auto OSObjTypeM = hasTypePointingTo(cxxRecordDecl(isDerivedFrom("OSMetaClassBase")));
auto OSObjSubclassM = hasTypePointingTo(
cxxRecordDecl(isDerivedFrom("OSObject")));
auto CastM = cStyleCastExpr(
allOf(hasSourceExpression(allOf(OSObjTypeM, unless(DynamicCastM))),
OSObjSubclassM)).bind(WarnAtNode);
auto Matches = match(stmt(forEachDescendant(CastM)), *D->getBody(), AM.getASTContext());
for (BoundNodes Match : Matches)
emitDiagnostics(Match, BR, ADC, this);
}
}
void ento::registerOSObjectCStyleCast(CheckerManager &Mgr) {
Mgr.registerChecker<OSObjectCStyleCastChecker>();
}
bool ento::shouldRegisterOSObjectCStyleCast(const CheckerManager &mgr) {
return true;
}
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