1 //===- OSObjectCStyleCast.cpp ------------------------------------*- C++ -*-==//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file defines OSObjectCStyleCast checker, which checks for C-style casts
10 // of OSObjects. Such casts almost always indicate a code smell,
11 // as an explicit static or dynamic cast should be used instead.
12 //===----------------------------------------------------------------------===//
14 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
15 #include "clang/ASTMatchers/ASTMatchFinder.h"
16 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
17 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
18 #include "clang/StaticAnalyzer/Core/Checker.h"
19 #include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
20 #include "llvm/Support/Debug.h"
22 using namespace clang;
24 using namespace ast_matchers;
28 const char *WarnAtNode = "OSObjCast";
30 class OSObjectCStyleCastChecker : public Checker<check::ASTCodeBody> {
32 void checkASTCodeBody(const Decl *D,
34 BugReporter &BR) const;
37 static void emitDiagnostics(const BoundNodes &Nodes,
39 AnalysisDeclContext *ADC,
40 const OSObjectCStyleCastChecker *Checker) {
41 const auto *CE = Nodes.getNodeAs<CastExpr>(WarnAtNode);
44 std::string Diagnostics;
45 llvm::raw_string_ostream OS(Diagnostics);
46 OS << "C-style cast of OSObject. Use OSDynamicCast instead.";
51 /*Name=*/"OSObject C-Style Cast",
52 /*BugCategory=*/"Security",
54 PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), ADC),
55 CE->getSourceRange());
58 static decltype(auto) hasTypePointingTo(DeclarationMatcher DeclM) {
59 return hasType(pointerType(pointee(hasDeclaration(DeclM))));
62 void OSObjectCStyleCastChecker::checkASTCodeBody(const Decl *D, AnalysisManager &AM,
63 BugReporter &BR) const {
65 AnalysisDeclContext *ADC = AM.getAnalysisDeclContext(D);
67 auto DynamicCastM = callExpr(callee(functionDecl(hasName("safeMetaCast"))));
69 auto OSObjTypeM = hasTypePointingTo(cxxRecordDecl(isDerivedFrom("OSMetaClassBase")));
70 auto OSObjSubclassM = hasTypePointingTo(
71 cxxRecordDecl(isDerivedFrom("OSObject")));
73 auto CastM = cStyleCastExpr(
74 allOf(hasSourceExpression(allOf(OSObjTypeM, unless(DynamicCastM))),
75 OSObjSubclassM)).bind(WarnAtNode);
77 auto Matches = match(stmt(forEachDescendant(CastM)), *D->getBody(), AM.getASTContext());
78 for (BoundNodes Match : Matches)
79 emitDiagnostics(Match, BR, ADC, this);
83 void ento::registerOSObjectCStyleCast(CheckerManager &Mgr) {
84 Mgr.registerChecker<OSObjectCStyleCastChecker>();
87 bool ento::shouldRegisterOSObjectCStyleCast(const CheckerManager &mgr) {