ACK/Cmt: [SRU][F/J][PATCH 0/1] CVE-2024-38630

[Mehmet Basaran]

Acked-by: Mehmet Basaran <mehmet.basaran at canonical.com>

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Koichiro Den <koichiro.den at canonical.com> writes:

> [Impact]
>
> 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.
>
> [Backport]
>
> For Jammy, the fix commit was cleanly applied.
> For Focal, I adjusted context due to lack of timer_shutdown_sync(),
> which was introduced on upstream in the following patch series:
>
>   [patch V3 00/17] timers: Provide timer_shutdown[_sync]()
>   https://lore.kernel.org/all/20221123201306.823305113@linutronix.de/]
>
> Even though part of it was pulled in via stable upstream. I did not
> backport the rest here since it would introduce unnecessary changes.
>
> [Fix]
>
> Noble:  fixed via stable (pending)
> Jammy:  Cleanly applied
> Focal:  Backport - adjusted contexts, see [Backport]
> Bionic: fix sent to esm ML
> Xenial: fix sent to esm ML
> Trusty: won't fix
>
> [Test case]
>
> Compile and boot tested
>
> [Where problems could occur]
>
> This fix affects those who use SMA CPU5 watchdog card, an issue with
> with this fix would lead to UAF access to PCI IO resource immediately
> released on cpu5wdt module unload.
>
>
> Duoming Zhou (1):
>   watchdog: cpu5wdt.c: Fix use-after-free bug caused by cpu5wdt_trigger
>
>  drivers/watchdog/cpu5wdt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> -- 
> 2.43.0
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