Re: [PATCH] USB: serial: keyspan: fix missing indat transfer sanity check

[Johan Hovold <johan@kernel.org>]

On Wed, May 20, 2026 at 12:12:30PM +0200, Johan Hovold wrote:
> Add the missing sanity check on the size of usa49wg indat transfers to
> avoid parsing stale or uninitialised slab data.
> 
> Fixes: 0ca1268e109a ("USB Serial Keyspan: add support for USA-49WG & USA-28XG")
> Cc: stable@vger.kernel.org	# 2.6.23
> Signed-off-by: Johan Hovold <johan@kernel.org>
> ---
>  drivers/usb/serial/keyspan.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/usb/serial/keyspan.c b/drivers/usb/serial/keyspan.c
> index 46448843541a..a267bc51afc1 100644
> --- a/drivers/usb/serial/keyspan.c
> +++ b/drivers/usb/serial/keyspan.c
> @@ -1187,6 +1187,10 @@ static void usa49wg_indat_callback(struct urb *urb)
>  	len = 0;
>  
>  	while (i < urb->actual_length) {
> +		if (urb->actual_length - i < 3) {
> +			dev_warn_ratelimited(&serial->dev, "malformed indat packet\n");

This dev_printk was a last minute addition before submitting which I
apparently failed to compile test. This should have been
&serial->interface->dev (or &urb->dev->dev).

Will fix up when applying.

> +			break;
> +		}
>  
>  		/* Check port number from message */
>  		if (data[i] >= serial->num_ports) {

Johan