qt5base-lts/src/dbus/qdbusserver.cpp
Ievgenii Meshcheriakov 90d3c5b951 QDBusServer: Fix potential crash when private pointer is null
Check that the private pointer is not null before attempting
to dereference it. This can happen, for example, when
a QDBusServer instance was constructed with an empty string
as address. Attempting to destroy an object constructed
this way was causing a segmentation fault on Linux.

Add a test case that attempts to construct a QDBusServer
object with an empty string as address to check that this
does not cause a segmentation fault anymore.

Pick-to: 6.5 6.2
Change-Id: I5fe63134026e2a9f509b61d452285891b1ec624d
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
2023-05-02 14:54:19 +02:00

181 lines
4.2 KiB
C++

// Copyright (C) 2016 The Qt Company Ltd.
// Copyright (C) 2016 Intel Corporation.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include "qdbusserver.h"
#include "qdbusconnection_p.h"
#include "qdbusconnectionmanager_p.h"
#include "qdbusutil_p.h"
#include <QtCore/private/qlocking_p.h>
#ifndef QT_NO_DBUS
QT_BEGIN_NAMESPACE
/*!
\class QDBusServer
\inmodule QtDBus
\brief The QDBusServer class provides peer-to-peer communication
between processes on the same computer.
*/
/*!
Constructs a QDBusServer with the given \a address, and the given
\a parent.
*/
QDBusServer::QDBusServer(const QString &address, QObject *parent)
: QObject(parent), d(nullptr)
{
if (address.isEmpty())
return;
if (!qdbus_loadLibDBus())
return;
QDBusConnectionManager *instance = QDBusConnectionManager::instance();
if (!instance)
return;
emit instance->serverRequested(address, this);
Q_ASSERT(d != nullptr);
QObject::connect(d, SIGNAL(newServerConnection(QDBusConnectionPrivate*)),
this, SLOT(_q_newConnection(QDBusConnectionPrivate*)), Qt::QueuedConnection);
}
/*!
Constructs a QDBusServer with the given \a parent. The server will listen
for connections in \c {/tmp} (on Unix systems) or on a TCP port bound to
localhost (elsewhere).
*/
QDBusServer::QDBusServer(QObject *parent)
: QObject(parent), d(nullptr)
{
#ifdef Q_OS_UNIX
// Use Unix sockets on Unix systems only
const QString address = QStringLiteral("unix:tmpdir=/tmp");
#else
const QString address = QStringLiteral("tcp:");
#endif
if (!qdbus_loadLibDBus())
return;
QDBusConnectionManager *instance = QDBusConnectionManager::instance();
if (!instance)
return;
emit instance->serverRequested(address, this);
Q_ASSERT(d != nullptr);
QObject::connect(d, SIGNAL(newServerConnection(QDBusConnectionPrivate*)),
this, SLOT(_q_newConnection(QDBusConnectionPrivate*)), Qt::QueuedConnection);
}
/*!
Destructs a QDBusServer
*/
QDBusServer::~QDBusServer()
{
if (!d)
return;
auto manager = QDBusConnectionManager::instance();
if (!manager)
return;
QMutexLocker locker(&manager->mutex);
QWriteLocker writeLocker(&d->lock);
for (const QString &name : std::as_const(d->serverConnectionNames))
manager->removeConnection(name);
d->serverConnectionNames.clear();
locker.unlock();
d->serverObject = nullptr;
d->ref.storeRelaxed(0);
d->deleteLater();
}
/*!
Returns \c true if this QDBusServer object is connected.
If it isn't connected, you need to call the constructor again.
*/
bool QDBusServer::isConnected() const
{
return d && d->server && q_dbus_server_get_is_connected(d->server);
}
/*!
Returns the last error that happened in this server.
This function is provided for low-level code.
*/
QDBusError QDBusServer::lastError() const
{
return d ? d->lastError : QDBusError(QDBusError::Disconnected, QDBusUtil::disconnectedErrorMessage());
}
/*!
Returns the address this server is associated with.
*/
QString QDBusServer::address() const
{
QString addr;
if (d && d->server) {
char *c = q_dbus_server_get_address(d->server);
addr = QString::fromUtf8(c);
q_dbus_free(c);
}
return addr;
}
/*!
\since 5.3
If \a value is set to true, an incoming connection can proceed even if the
connecting client is not authenticated as a user.
By default, this value is false.
\sa isAnonymousAuthenticationAllowed()
*/
void QDBusServer::setAnonymousAuthenticationAllowed(bool value)
{
if (!d)
return;
d->anonymousAuthenticationAllowed = value;
}
/*!
\since 5.3
Returns true if anonymous authentication is allowed.
\sa setAnonymousAuthenticationAllowed()
*/
bool QDBusServer::isAnonymousAuthenticationAllowed() const
{
if (!d)
return false;
return d->anonymousAuthenticationAllowed;
}
/*!
\fn void QDBusServer::newConnection(const QDBusConnection &connection)
This signal is emitted when a new client connection \a connection is
established to the server.
*/
QT_END_NAMESPACE
#include "moc_qdbusserver.cpp"
#endif // QT_NO_DBUS