Re: [PATCH] ALSA: firewire-lib: Avoid division by zero in apply_constraint_to_size()

[Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>]

Hi,

On Fri, Oct 18, 2024 at 09:00:18AM +0300, Andrey Shumilin wrote:
> The step variable is initialized to zero. It is changed in the loop,
> but if it's not changed it will remain zero. Add a variable check
> before the division.
> 
> The observed behavior was introduced by commit 826b5de90c0b
> ("ALSA: firewire-lib: fix insufficient PCM rule for period/buffer size"),
> and it is difficult to show that any of the interval parameters will
> satisfy the snd_interval_test() condition with data from the
> amdtp_rate_table[] table.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 826b5de90c0b ("ALSA: firewire-lib: fix insufficient PCM rule for period/buffer size")
> Signed-off-by: Andrey Shumilin <shum.sdl@xxxxxxxx>
> ---
>  sound/firewire/amdtp-stream.c | 3 +++
>  1 file changed, 3 insertions(+)

I think it a good catch.

Reviewed-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>


Regards

Takashi Sakamoto