ALSA: firewire-lib: Avoid division by zero in apply_constraint_to_size()

[ Upstream commit 72cafe63b35d06b5cfbaf807e90ae657907858da ]

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@nppct.ru>
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://patch.msgid.link/20241018060018.1189537-1-shum.sdl@nppct.ru
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Andrey Shumilin 2024-10-18 09:00:18 +03:00 committed by Ksawlii
parent a2c183d885
commit dacb1a8ade

View file

@ -163,6 +163,9 @@ static int apply_constraint_to_size(struct snd_pcm_hw_params *params,
step = max(step, amdtp_syt_intervals[i]);
}
if (step == 0)
return -EINVAL;
t.min = roundup(s->min, step);
t.max = rounddown(s->max, step);
t.integer = 1;