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Diffstat (limited to '')
| -rw-r--r-- | compilerplugins/clang/weakobject.cxx | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/compilerplugins/clang/weakobject.cxx b/compilerplugins/clang/weakobject.cxx new file mode 100644 index 000000000..afa652bef --- /dev/null +++ b/compilerplugins/clang/weakobject.cxx @@ -0,0 +1,167 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + */ + +#ifndef LO_CLANG_SHARED_PLUGINS + +#include "check.hxx" +#include "plugin.hxx" + +/* OWeakObject::release() disposes weak references. If that isn't done + * because a sub-class improperly overrides release() then + * OWeakConnectionPoint::m_pObject continues to point to the deleted object + * and that could result in use-after-free. + */ + +namespace { + +class WeakObject + : public loplugin::FilteringPlugin<WeakObject> +{ + +public: + explicit WeakObject(loplugin::InstantiationData const& rData): FilteringPlugin(rData) + {} + + virtual bool preRun() override { + return compiler.getLangOpts().CPlusPlus; // no OWeakObject in C + } + void run() override { + if( preRun()) { + TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); + } + } + + bool isDerivedFromOWeakObject(CXXMethodDecl const*const pMethodDecl) + { + QualType const pClass(pMethodDecl->getParent()->getTypeForDecl(), 0); + if (loplugin::TypeCheck(pClass).Class("OWeakObject").Namespace("cppu")) + { + return true; + } + // hopefully it's faster to recurse overridden methods than the + // thicket of WeakImplHelper32 but that is purely speculation + for (auto it = pMethodDecl->begin_overridden_methods(); + it != pMethodDecl->end_overridden_methods(); ++it) + { + if (isDerivedFromOWeakObject(*it)) + { + return true; + } + } + return false; + } + + bool VisitCXXMethodDecl(CXXMethodDecl const*const pMethodDecl) + { + if (ignoreLocation(pMethodDecl)) { + return true; + } + if (!pMethodDecl->isThisDeclarationADefinition() + || pMethodDecl->isLateTemplateParsed()) + { + return true; + } + if (!pMethodDecl->isInstance()) { + return true; + } +// this is too "simple", if a NamedDecl class has a getName() member expecting it to actually work would clearly be unreasonable if (pMethodDecl->getName() != "release") { + if (auto const i = pMethodDecl->getIdentifier()) { + if (i != nullptr && !i->isStr("release")) { + return true; + } + } + if (pMethodDecl->getNumParams() != 0) { + return true; + } + if (loplugin::TypeCheck(QualType(pMethodDecl->getParent()->getTypeForDecl(), 0)).Class("OWeakObject").Namespace("cppu")) + { + return true; + } + + CXXMethodDecl const* pOverridden(nullptr); + for (auto it = pMethodDecl->begin_overridden_methods(); + it != pMethodDecl->end_overridden_methods(); ++it) + { + if (auto const i = (*it)->getIdentifier()) { + if (i != nullptr && i->isStr("release")) { + pOverridden = *it; + break; + } + } + } + if (pOverridden == nullptr) + { + return true; + } + if (!isDerivedFromOWeakObject(pOverridden)) + { + return true; + } + CompoundStmt const*const pCompoundStatement( + dyn_cast<CompoundStmt>(pMethodDecl->getBody())); + for (auto i = pCompoundStatement->body_begin(); + i != pCompoundStatement->body_end(); ++i) + { + // note: this is not a CXXMemberCallExpr + CallExpr const*const pCallExpr(dyn_cast<CallExpr>(*i)); + if (pCallExpr) + { + // note: this is only sometimes a CXXMethodDecl + FunctionDecl const*const pCalled(pCallExpr->getDirectCallee()); + if (pCalled->getName() == "release") + { +//this never works && pCalled == pOverridden + if (pCalled->getParent() == pOverridden->getParent()) + { + return true; + } + // Allow this convenient shortcut: + auto td = dyn_cast<TypeDecl>(pCalled->getParent()); + if (td != nullptr + && (loplugin::TypeCheck(td).Class("OWeakObject").Namespace("cppu").GlobalNamespace() + || loplugin::TypeCheck(td).Class("OWeakAggObject").Namespace("cppu").GlobalNamespace())) + { + return true; + } + } + } + } + + // whitelist + auto tc = loplugin::TypeCheck(pMethodDecl->getParent()); + if ( tc.Class("OWeakAggObject").Namespace("cppu").GlobalNamespace() // conditional call + || tc.Class("WeakComponentImplHelperBase").Namespace("cppu").GlobalNamespace() // extra magic + || tc.Class("WeakAggComponentImplHelperBase").Namespace("cppu").GlobalNamespace() // extra magic + || tc.Class("CDOMImplementation").Namespace("DOM").GlobalNamespace() // a static oddity + || tc.Class("SwXTextFrame").GlobalNamespace() // ambiguous, 3 parents + || tc.Class("SwXTextDocument").GlobalNamespace() // ambiguous, ~4 parents + || tc.Class("SdStyleSheet").GlobalNamespace() // same extra magic as WeakComponentImplHelperBase + || tc.Class("SdXImpressDocument").GlobalNamespace() // same extra magic as WeakComponentImplHelperBase + ) + { + return true; + } + + report(DiagnosticsEngine::Warning, + "override of OWeakObject::release() does not call superclass release()", + pMethodDecl->getLocation()) + << pMethodDecl->getSourceRange(); + + return true; + } + +}; + +loplugin::Plugin::Registration<WeakObject> weakobject("weakobject"); + +} // namespace + +#endif // LO_CLANG_SHARED_PLUGINS + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |