OSObjectCStyleCast.cpp source code [clang_source_code/lib/StaticAnalyzer/Checkers/OSObjectCStyleCast.cpp]

1	//===- OSObjectCStyleCast.cpp ------------------------------------- C++ --==//
2	//
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
6	//
7	//===----------------------------------------------------------------------===//
8	//
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	//===----------------------------------------------------------------------===//
13
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"
21
22	using namespace clang;
23	using namespace ento;
24	using namespace ast_matchers;
25
26	namespace {
27
28	const char *WarnAtNode = "OSObjCast";
29
30	class OSObjectCStyleCastChecker : public Checker<check::ASTCodeBody> {
31	public:
32	void checkASTCodeBody(const Decl *D,
33	AnalysisManager &AM,
34	BugReporter &BR) const;
35	};
36
37	static void emitDiagnostics(const BoundNodes &Nodes,
38	BugReporter &BR,
39	AnalysisDeclContext *ADC,
40	const OSObjectCStyleCastChecker *Checker) {
41	const auto *CE = Nodes.getNodeAs<CastExpr>(WarnAtNode);
42	assert(CE);
43
44	std::string Diagnostics;
45	llvm::raw_string_ostream OS(Diagnostics);
46	OS << "C-style cast of OSObject. Use OSDynamicCast instead.";
47
48	BR.EmitBasicReport(
49	ADC->getDecl(),
50	Checker,
51	/Name=/"OSObject C-Style Cast",
52	/Category=/"Security",
53	OS.str(),
54	PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), ADC),
55	CE->getSourceRange());
56	}
57
58	static auto hasTypePointingTo(DeclarationMatcher DeclM)
59	-> decltype(hasType(pointerType())) {
60	return hasType(pointerType(pointee(hasDeclaration(DeclM))));
61	}
62
63	void OSObjectCStyleCastChecker::checkASTCodeBody(const Decl *D, AnalysisManager &AM,
64	BugReporter &BR) const {
65
66	AnalysisDeclContext *ADC = AM.getAnalysisDeclContext(D);
67
68	auto DynamicCastM = callExpr(callee(functionDecl(hasName("safeMetaCast"))));
69
70	auto OSObjTypeM = hasTypePointingTo(cxxRecordDecl(isDerivedFrom("OSMetaClassBase")));
71	auto OSObjSubclassM = hasTypePointingTo(
72	cxxRecordDecl(isDerivedFrom("OSObject")));
73
74	auto CastM = cStyleCastExpr(
75	allOf(hasSourceExpression(allOf(OSObjTypeM, unless(DynamicCastM))),
76	OSObjSubclassM)).bind(WarnAtNode);
77
78	auto Matches = match(stmt(forEachDescendant(CastM)), *D->getBody(), AM.getASTContext());
79	for (BoundNodes Match : Matches)
80	emitDiagnostics(Match, BR, ADC, this);
81	}
82	}
83
84	void ento::registerOSObjectCStyleCast(CheckerManager &Mgr) {
85	Mgr.registerChecker<OSObjectCStyleCastChecker>();
86	}
87
88	bool ento::shouldRegisterOSObjectCStyleCast(const LangOptions &LO) {
89	return true;
90	}
91

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