Subject: CVE-2024-38630: watchdog: cpu5wdt.c: Fix use-after-free bug caused by cpu5wdt_trigger

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

watchdog: cpu5wdt.c: Fix use-after-free bug caused by cpu5wdt_trigger

When the cpu5wdt module is removing, the origin code uses del_timer() to
de-activate the timer. If the timer handler is running, del_timer() could
not stop it and will return directly. If the port region is released by
release_region() and then the timer handler cpu5wdt_trigger() calls outb()
to write into the region that is released, the use-after-free bug will
happen.

Change del_timer() to timer_shutdown_sync() in order that the timer handler
could be finished before the port region is released.

The Linux kernel CVE team has assigned CVE-2024-38630 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 2.6.12 with commit 1da177e4c3f4 and fixed in 6.6.33 with commit 9b1c063ffc07
	Issue introduced in 2.6.12 with commit 1da177e4c3f4 and fixed in 6.9.4 with commit f19686d61650
	Issue introduced in 2.6.12 with commit 1da177e4c3f4 and fixed in 6.10 with commit 573601521277

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-38630
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/watchdog/cpu5wdt.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/9b1c063ffc075abf56f63e55d70b9778ff534314
	https://git.kernel.org/stable/c/f19686d616500cd0d47b30cee82392b53f7f784a
	https://git.kernel.org/stable/c/573601521277119f2e2ba5f28ae6e87fc594f4d4