virtio: console: prevent use-after-free of port name in port unplug

Remove the debugfs path before freeing port->name, to prevent a possible
use-after-free.

Reported-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index d0e75aa..b79cf3e 100644 (file)
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1591,9 +1591,8 @@ static void unplug_port(struct port *port)
        device_destroy(pdrvdata.class, port->dev->devt);
        cdev_del(port->cdev);
 
-       kfree(port->name);
-
        debugfs_remove(port->debugfs_file);
+       kfree(port->name);
 
        /*
         * Locks around here are not necessary - a port can't be