Re: [PATCH] staging: comedi: ni_tio: Adjust clock period calculation in ni_tio_set_clock_src()

[Ian Abbott]

On 17/09/2024 07:23, Aleksandr Mishin wrote:
> In ni_tio_set_clock_src() clock period is a subject to overflow because
> 'period_ns' (which comes from user, may have any value and is not
> validated anywhere) is not cast to a larger data type before performing
> arithmetic.
>
> Cast 'period_ns' to u64 to prevent overflow.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 3e90b1c7ebe9 ("staging: comedi: ni_tio: tidy up ni_tio_set_clock_src() and helpers")
> Signed-off-by: Aleksandr Mishin <amishin@xxxxxxxxxx>
> ---
>   drivers/comedi/drivers/ni_tio.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/comedi/drivers/ni_tio.c b/drivers/comedi/drivers/ni_tio.c
> index da6826d77e60..98b5b44416cf 100644
> --- a/drivers/comedi/drivers/ni_tio.c
> +++ b/drivers/comedi/drivers/ni_tio.c
> @@ -800,7 +800,7 @@ static int ni_tio_set_clock_src(struct ni_gpct *counter,
>   				GI_PRESCALE_X2(counter_dev->variant) |
>   				GI_PRESCALE_X8(counter_dev->variant), bits);
>   	}
> -	counter->clock_period_ps = period_ns * 1000;
> +	counter->clock_period_ps = (u64)period_ns * 1000;
>   	ni_tio_set_sync_mode(counter);
>   	return 0;
>   }

Thanks.  The patch looks good but since comedi was migrated out of 
staging, it should no longer be tagged as "staging:" in the title.

Reviewed-by: Ian Abbott <abbotti@xxxxxxxxx>

--
-=( Ian Abbott <abbotti@xxxxxxxxx> || MEV Ltd. is a company  )=-
-=( registered in England & Wales.  Regd. number: 02862268.  )=-
-=( Regd. addr.: S11 & 12 Building 67, Europa Business Park, )=-
-=( Bird Hall Lane, STOCKPORT, SK3 0XA, UK. || www.mev.co.uk )=-