[PATCH 4.4 055/101] virtio_console: fix a crash in config_work_handler

From: Greg Kroah-Hartman
Date: Mon Jul 03 2017 - 10:59:24 EST

4.4-stable review patch. If anyone has any objections, please let me know.


From: "G. Campana" <gcampana@xxxxxxxxxxxxx>

[ Upstream commit 8379cadf71c3ee8173a1c6fc1ea7762a9638c047 ]

Using control_work instead of config_work as the 3rd argument to
container_of results in an invalid portdev pointer. Indeed, the work
structure is initialized as below:

INIT_WORK(&portdev->config_work, &config_work_handler);

It leads to a crash when portdev->vdev is dereferenced later. This
is triggered when the guest uses a virtio-console without multiport
feature and receives a config_changed virtio interrupt.

Signed-off-by: G. Campana <gcampana@xxxxxxxxxxxxx>
Reviewed-by: Amit Shah <amit.shah@xxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/char/virtio_console.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1864,7 +1864,7 @@ static void config_work_handler(struct w
struct ports_device *portdev;

- portdev = container_of(work, struct ports_device, control_work);
+ portdev = container_of(work, struct ports_device, config_work);
if (!use_multiport(portdev)) {
struct virtio_device *vdev;
struct port *port;