linux-kernel - Re: [PATCH] iio: fix infinite loop for gain_to

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5dae4924-5c07-48b6-a818-809cd4dd1c80@gmail.com>
Date: Thu, 31 Oct 2024 09:25:16 +0200
From: Matti Vaittinen <mazziesaccount@...il.com>
To: Zicheng Qu <quzicheng@...wei.com>, jic23@...nel.org, lars@...afoo.de,
 linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: tanghui20@...wei.com, zhangqiao22@...wei.com, judy.chenhui@...wei.com
Subject: Re: [PATCH] iio: fix infinite loop for gain_to_scaletables()

Thanks again Zicheng!

On 31/10/2024 03:46, Zicheng Qu wrote:
> In iio_gts_build_avail_time_table(), it is checked that gts->num_itime is
> non-zero, but gts->num_itime is not checked in gain_to_scaletables(). The
> variable time_idx is initialized as gts->num_itime - 1. This implies that
> time_idx might initially be set to -1 (0 - 1 = -1). Consequently, using
> while (time_idx--) could lead to an infinite loop.
> 
> Cc: stable@...r.kernel.org # v6.6+
> Fixes: 38416c28e168 ("iio: light: Add gain-time-scale helpers")
> Signed-off-by: Zicheng Qu <quzicheng@...wei.com>
> ---
>   drivers/iio/industrialio-gts-helper.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/industrialio-gts-helper.c b/drivers/iio/industrialio-gts-helper.c
> index 59d7615c0f56..f3acd392f4fc 100644
> --- a/drivers/iio/industrialio-gts-helper.c
> +++ b/drivers/iio/industrialio-gts-helper.c
> @@ -205,7 +205,7 @@ static int gain_to_scaletables(struct iio_gts *gts, int **gains, int **scales)
>   	memcpy(all_gains, gains[time_idx], gain_bytes);
>   	new_idx = gts->num_hwgain;
>   
> -	while (time_idx--) {
> +	while (time_idx-- > 0) {
>   		for (j = 0; j < gts->num_hwgain; j++) {
>   			int candidate = gains[time_idx][j];
>   			int chk;

This, too, brings the question if supporting 0 times is worth.

At least this shows that it'd be nice to cover the "only times, no 
hw-gains" and "no times, only hw-gains" cases in the Kunit tests...

Anyways - Thanks!

Reviewed-by: Matti Vaittinen <mazziesaccount@...il.com>

Yours,
	-- Matti