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>

2 files changed, 7 insertions, 0 deletions

diff --git a/tests/auto/dbus/qdbusconnection/tst_qdbusconnection.cpp b/tests/auto/dbus/qdbusconnection/tst_qdbusconnection.cpp
index 09ce947ccc..42e898eda7 100644
--- a/tests/auto/dbus/qdbusconnection/tst_qdbusconnection.cpp
+++ b/tests/auto/dbus/qdbusconnection/tst_qdbusconnection.cpp
@@ -1412,6 +1412,11 @@ void tst_QDBusConnection::pendingCallWhenDisconnected()
 #endif
 }
 
+void tst_QDBusConnection::emptyServerAddress()
+{
+    QDBusServer server({}, nullptr);
+}
+
 QString MyObject::path;
 QString MyObjectWithoutInterface::path;
 QString MyObjectWithoutInterface::interface;
diff --git a/tests/auto/dbus/qdbusconnection/tst_qdbusconnection.h b/tests/auto/dbus/qdbusconnection/tst_qdbusconnection.h
index 058f4e8115..0aec2aa0bd 100644
--- a/tests/auto/dbus/qdbusconnection/tst_qdbusconnection.h
+++ b/tests/auto/dbus/qdbusconnection/tst_qdbusconnection.h
@@ -115,6 +115,8 @@ private slots:
     void callVirtualObjectLocal();
     void pendingCallWhenDisconnected();
 
+    void emptyServerAddress();
+
 public:
     QString serviceName() const { return "org.qtproject.Qt.Autotests.QDBusConnection"; }
     bool callMethod(const QDBusConnection &conn, const QString &path);