Re: [PATCH] media: cec: extron-da-hd-4k-plus: add sanity check

[Hans Verkuil <hverkuil+cisco@kernel.org>]

On 18/06/2026 13:03, Hans Verkuil wrote:
> Add check to prevent overflowing msg.msg[] in case the incoming data
> is malformed.
> 
> Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>

Fixes: 056f2821b631 ("media: cec: extron-da-hd-4k-plus: add the Extron DA HD 4K Plus CEC driver")
Cc: stable@vger.kernel.org

Regards,

	Hans

> ---
> diff --git a/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c b/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c
> index 3381d86096a1..3c6ce6f3d93e 100644
> --- a/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c
> +++ b/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c
> @@ -657,7 +657,8 @@ static void extron_process_received(struct extron_port *port, const char *data)
>  	if (!port || port->disconnected)
>  		return;
> 
> -	if (len < 5 || (len - 2) % 3 || data[len - 2] != '*')
> +	if (len < 5 || ((len - 2) / 3 > sizeof(msg.msg)) ||
> +	    (len - 2) % 3 || data[len - 2] != '*')
>  		goto malformed;
> 
>  	while (*data != '*') {
>