Re: [PATCH 5.14 165/169] usbnet: sanity check for maxpacket

Johan Hovold
2021-10-26T12:34:16Z

On Mon, Oct 25, 2021 at 09:15:46PM +0200, Greg Kroah-Hartman wrote:
> From: Oliver Neukum <oneukum@suse.com>
>
> commit 397430b50a363d8b7bdda00522123f82df6adc5e upstream.
>
> maxpacket of 0 makes no sense and oopses as we need to divide
> by it. Give up.
>
> V2: fixed typo in log and stylistic issues
>
> Signed-off-by: Oliver Neukum <oneukum@suse.com>
> Reported-by: syzbot+76bb1d34ffa0adc03baa@syzkaller.appspotmail.com
> Reviewed-by: Johan Hovold <johan@kernel.org>
> Link: https://lore.kernel.org/r/20211021122944.21816-1-oneukum@suse.com
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Please drop this one from all stable queues until

https://lore.kernel.org/r/20211026124015.3025136-1-wanghai38@huawei.com

has landed.

> ---
> drivers/net/usb/usbnet.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> --- a/drivers/net/usb/usbnet.c
> +++ b/drivers/net/usb/usbnet.c
> @@ -1788,6 +1788,10 @@ usbnet_probe (struct usb_interface *udev
> if (!dev->rx_urb_size)
> dev->rx_urb_size = dev->hard_mtu;
> dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
> + if (dev->maxpacket == 0) {
> + /* that is a broken device */
> + goto out4;
> + }
>
> /* let userspace know we have a random address */
> if (ether_addr_equal(net->dev_addr, node_id))

Johan