93 lines
3.5 KiB
C++
93 lines
3.5 KiB
C++
//===- 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 {
|
|
static constexpr const char *const WarnAtNode = "WarnAtNode";
|
|
static constexpr const char *const WarnRecordDecl = "WarnRecordDecl";
|
|
|
|
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);
|
|
const CXXRecordDecl *RD = Nodes.getNodeAs<CXXRecordDecl>(WarnRecordDecl);
|
|
assert(CE && RD);
|
|
|
|
std::string Diagnostics;
|
|
llvm::raw_string_ostream OS(Diagnostics);
|
|
OS << "C-style cast of an OSObject is prone to type confusion attacks; "
|
|
<< "use 'OSRequiredCast' if the object is definitely of type '"
|
|
<< RD->getNameAsString() << "', or 'OSDynamicCast' followed by "
|
|
<< "a null check if unsure",
|
|
|
|
BR.EmitBasicReport(
|
|
ADC->getDecl(),
|
|
Checker,
|
|
/*Name=*/"OSObject C-Style Cast",
|
|
categories::SecurityError,
|
|
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")).bind(WarnRecordDecl));
|
|
|
|
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;
|
|
}
|