usb: misc: lvs: fix race condition in disconnect handling

[ Upstream commit c4ba329cabca7c839ab48fb58b5bcc2582951a48 ]

There is a small window during which the an URB may
remain active after disconnect has returned. If in that case
already freed memory may be accessed and executed.

The fix is to poison the URB befotre the work is flushed.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/misc/lvstest.c b/drivers/usb/misc/lvstest.c
index d3d1247..bd6e06e 100644 (file)
--- a/drivers/usb/misc/lvstest.c
+++ b/drivers/usb/misc/lvstest.c
@@ -433,6 +433,7 @@ static void lvs_rh_disconnect(struct usb_interface *intf)
        struct lvs_rh *lvs = usb_get_intfdata(intf);
 
        sysfs_remove_group(&intf->dev.kobj, &lvs_attr_group);
+       usb_poison_urb(lvs->urb); /* used in scheduled work */
        flush_work(&lvs->rh_work);
        usb_free_urb(lvs->urb);
 }