Re: [PATCH] wifi: ath6kl: Check that the read operation returns a data length of 0

Greg KH
2024-08-25T07:25:41Z

On Sun, Aug 25, 2024 at 03:10:03PM +0800, Edward Adam Davis wrote:
> If the data length returned by the device is 0, the read operation
> should be considered a failure.
>
> Reported-and-tested-by: syzbot+92c6dd14aaa230be6855@syzkaller.appspotmail.com
> Signed-off-by: Edward Adam Davis <eadavis@qq.com>
> ---
> drivers/net/wireless/ath/ath6kl/usb.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/net/wireless/ath/ath6kl/usb.c b/drivers/net/wireless/ath/ath6kl/usb.c
> index 5220809841a6..2a89bab81b24 100644
> --- a/drivers/net/wireless/ath/ath6kl/usb.c
> +++ b/drivers/net/wireless/ath/ath6kl/usb.c
> @@ -1034,6 +1034,9 @@ static int ath6kl_usb_bmi_read(struct ath6kl *ar, u8 *buf, u32 len)
> ath6kl_err("Unable to read the bmi data from the device: %d\n",
> ret);
> return ret;
> + } else {
> + ath6kl_err("Actual read the bmi data length is 0 from the device\n");
> + return -EIO;

Close, but not quite there. ath6kl_usb_submit_ctrl_in() needs to verify
that the actual amount of data was read that was asked for. If a short
read happens (or a long one), then an error needs to propagate out, not
just 0. See the "note:" line in that function for what needs to be
properly checked.

hope this helps,

greg k-h