CVE-2021-47324 Information

Description

In the Linux kernel the following vulnerability has been resolved:

watchdog: Fix possible use-after-free in wdt_startup()

This module’s remove path calls del_timer(). However that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver’s remove function has finished which would result in a use-after-free.

Fix by calling del_timer_sync() which makes sure the timer handler has finished and unable to re-schedule itself.

Reference

https://git.kernel.org/stable/c/63a3dc24bd053792f84cb4eef0168b1266202a02 https://git.kernel.org/stable/c/862f2b5a7c38762ac9e369daefbf361a91aca685 https://git.kernel.org/stable/c/0ac50a76cf3cd63db000648b3b19f3f98b8aaa76 https://git.kernel.org/stable/c/dc9403097be52d57a5c9c35efa9be79d166a78af https://git.kernel.org/stable/c/146cc288fb80c662c9c35e7bc58325d1ac0a7875 https://git.kernel.org/stable/c/a397cb4576fc2fc802562418b3a50b8f67d60d31 https://git.kernel.org/stable/c/b4ebf4a4692e84163a69444c70ad515de06e2259 https://git.kernel.org/stable/c/8adbbe6c86bb13e14f8a19e036ae5f4f5661fd90 https://git.kernel.org/stable/c/c08a6b31e4917034f0ed0cb457c3bb209576f542