Re: [PATCH v4] media: siano: Replace strlcat() with scnprintf() in sms_ir_init()

[Alejandro Colomar <alx+linux-hardening@kernel.org>]

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> Date: 2026-11-06 19:39:28-0800
> From: Mariia Nikitash <nikitash.mariiaw@gmail.com>
>
> In preparation for removing the deprecated strlcat() API[1], replace
> the strscpy() and strlcat() calls with a single bounded scnprintf()
> call to construct the IR device path.
> 
> This preserves the original NUL-terminated output, including partial
> or omitted "/ir0" suffixes when the 32-byte buffer is too small.
> 
> Link: https://github.com/KSPP/linux/issues/370 [1]
> Signed-off-by: Mariia Nikitash <nikitash.mariiaw@gmail.com>

Reviewed-by: Alejandro Colomar <alx@kernel.org>


Cheers,
Alex

> ---
> Changes in v4:
> - Replace seq_buf with scnprintf(), as suggested by David Laight
>   and Kees Cook.
> - Remove the unused seq_buf include and local variable.
> 
> Changes in v3:
> - Replace snprintf() with seq_buf operations after reproducing
>   the GCC -Wformat-truncation warning noted by David Laight.
> - Drop the previous Reviewed-by tags due to the implementation change.
> 
> Changes in v2:
> - No code changes.
> - Remove the statement about buffer capacities from the commit message.
> - Add Reviewed-by tags from Alejandro Colomar and Shihuang Liu.
> 
>  drivers/media/common/siano/smsir.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/common/siano/smsir.c b/drivers/media/common/siano/smsir.c
> index 283770d583d5..6952871c5816 100644
> --- a/drivers/media/common/siano/smsir.c
> +++ b/drivers/media/common/siano/smsir.c
> @@ -55,8 +55,8 @@ int sms_ir_init(struct smscore_device_t *coredev)
>  	snprintf(coredev->ir.name, sizeof(coredev->ir.name),
>  		 "SMS IR (%s)", sms_get_board(board_id)->name);
>  
> -	strscpy(coredev->ir.phys, coredev->devpath, sizeof(coredev->ir.phys));
> -	strlcat(coredev->ir.phys, "/ir0", sizeof(coredev->ir.phys));
> +	scnprintf(coredev->ir.phys, sizeof(coredev->ir.phys),
> +		  "%s/ir0", coredev->devpath);
>  
>  	dev->device_name = coredev->ir.name;
>  	dev->input_phys = coredev->ir.phys;
> -- 
> 2.43.0
> 
> 

-- 
<https://www.alejandro-colomar.es>

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