Re: [patch 2/2 v2] USB: keyspan: add a sanity test on "len"

walter harms
2013-04-05T07:09:04Z

Am 05.04.2013 07:43, schrieb Dan Carpenter:
> "len" comes from the USB transfer and it's probably correct. The thing
> is that we already have similar checks like:
>
> if (data[i] >= serial->num_ports) {
>
> So adding a sanity test here matches the rest of the code and is a good
> idea.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2: No change. Rebased.
>
> diff --git a/drivers/usb/serial/keyspan.c b/drivers/usb/serial/keyspan.c
> index 3d303f0..eb30d7b 100644
> --- a/drivers/usb/serial/keyspan.c
> +++ b/drivers/usb/serial/keyspan.c
> @@ -727,14 +727,15 @@ static void usa49wg_indat_callback(struct urb *urb)
> if ((data[i] & 0x80) = 0) {
> /* no error on any byte */
> i++;
> - for (x = 1; x < len ; ++x)
> + for (x = 1; x < len && i < urb->actual_length; ++x)
> tty_insert_flip_char(&port->port,
> data[i++], 0);

maybe is is a bit late ...
mixing i,x here is prone to error, the casual reader will be confused.
i suggest the following variation.
for (x = 1; x < len && i < urb->actual_length; ++x)
if (i < urb->actual_length)
tty_insert_flip_char(&port->port,ata[i++], 0);

> } else {
> /*
> * some bytes had errors, every byte has status
> */
> - for (x = 0; x + 1 < len; x += 2) {
> + for (x = 0; x + 1 < len &&
> + i + 1 < urb->actual_length; x += 2) {
> int stat = data[i], flag = 0;
>
> if (stat & RXERROR_OVERRUN)
same as above.

re,
wh

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