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

Wander Lairson Costa requested to merge walac/centos-stream-9:bz2215907-r592 into main

Bugzilla: https://bugzilla.redhat.com/2215907

CVE: CVE-2023-35825

commit 63264422785021704c39b38f65a78ab9e4a186d7

Author: Zheng Wang zyytlz.wz@163.com

Date: Wed Mar 8 00:43:38 2023 +0800

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: Zheng Wang <zyytlz.wz@163.com>
Link: https://lore.kernel.org/r/20230307164338.1246287-1-zyytlz.wz@163.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Signed-off-by: Wander Lairson Costa wander@redhat.com

Edited by Wander Lairson Costa

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