qt: playlist_controller: Ensure the path points to a directory

Not doing so could end up opening a file with the default application
associated with it, instead of opening a folder, leading to a potential
remote code execution.

Reported-by: Fabian Bräunlein <fabian@positive.security>
Reported-by: Lukas Euler <lukas@positive.security>
Signed-off-by: Hugo Beauzée-Luyssen <hugo@beauzee.fr>

modules/gui/qt/components/playlist/standardpanel.cpp

@@ -322,8 +322,10 @@ void StandardPLPanel::popupAction( QAction *action )
         temp = model->getURI( index );
         if( ! temp.isEmpty() ) path = vlc_uri2path( temp.toLatin1().constData() );
         if( path == NULL ) return;
+        temp = QFileInfo( qfu( path ) ).absolutePath();
+        if( !QFileInfo( temp ).isDir() ) return;
         QDesktopServices::openUrl(
-                    QUrl::fromLocalFile( QFileInfo( qfu( path ) ).absolutePath() ) );
+                    QUrl::fromLocalFile( temp ) );
         free( path );
         break;