Re: [PATCH] USB: io_edgeport: fix slab-out-of-bounds Read in edge_interrupt_callback

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Mar 25, 2020 at 03:52:37PM +0800, Qiujun Huang wrote:
> The boundary condition should be (length - 1) as we access data[position+1].
> 
> Reported-and-tested-by: syzbot+37ba33391ad5f3935bbd@syzkaller.appspotmail.com
> Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
> ---
>  drivers/usb/serial/io_edgeport.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
> index 5737add..4cca0b8 100644
> --- a/drivers/usb/serial/io_edgeport.c
> +++ b/drivers/usb/serial/io_edgeport.c
> @@ -710,7 +710,7 @@ static void edge_interrupt_callback(struct urb *urb)
>  		/* grab the txcredits for the ports if available */
>  		position = 2;
>  		portNumber = 0;
> -		while ((position < length) &&
> +		while ((position < length - 1) &&
>  				(portNumber < edge_serial->serial->num_ports)) {
>  			txCredits = data[position] | (data[position+1] << 8);
>  			if (txCredits) {
> -- 
> 1.8.3.1
> 

Johan, any objection from me taking this in my tree now?

thanks,

greg k-h