Commit 63264422 authored by Zheng Wang's avatar Zheng Wang Committed by Ulf Hansson
Browse files

memstick: r592: Fix UAF bug in r592_remove due to race condition 



In r592_probe, dev->detect_timer was bound with r592_detect_timer.
In r592_irq function, the timer function will be invoked by mod_timer.

If we remove the module which will call hantro_release to make cleanup,
there may be a unfinished work. The possible sequence is as follows,
which will cause a typical UAF bug.

Fix it by canceling the work before cleanup in r592_remove.

CPU0                  CPU1

                    |r592_detect_timer
r592_remove         |
  memstick_free_host|
  put_device;       |
  kfree(host);      |
                    |
                    | queue_work
                    |   &host->media_checker //use

Signed-off-by: default avatarZheng Wang <zyytlz.wz@163.com>
Link: https://lore.kernel.org/r/20230307164338.1246287-1-zyytlz.wz@163.com


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 4b4b7ac7

drivers/memstick/host/r592.c

+1 −1
Original line number Diff line number Diff line
@@ -829,7 +829,7 @@ static void r592_remove(struct pci_dev *pdev) 
	/* Stop the processing thread.

	That ensures that we won't take any more requests */

	kthread_stop(dev->io_thread);



	del_timer_sync(&dev->detect_timer);

	r592_enable_device(dev, false);



	while (!error && dev->req) {