Emilio López <emilio.lo...@collabora.co.uk> writes:
> diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
> index 38ae877c..bf40aa6 100644
> --- a/drivers/usb/core/devio.c
> +++ b/drivers/usb/core/devio.c
> @@ -77,6 +77,8 @@ struct usb_dev_state {
> unsigned long ifclaimed;
> u32 secid;
> u32 disabled_bulk_eps;
> + bool privileges_dropped;
> + unsigned long interface_allowed_mask;
> };
>
> struct async {
> @@ -641,6 +643,14 @@ static int claimintf(struct usb_dev_state *ps, unsigned
> int ifnum)
> if (test_bit(ifnum, &ps->ifclaimed))
> return 0;
>
> + if (ps->privileges_dropped) {
> + if (ifnum >= 8*sizeof(ps->interface_allowed_mask))
> + return -EINVAL;
I don't think you need this runtime test. You can just make sure that
sizeof(ps->interface_allowed_mask) == sizeof(ps->ifclaimed) at build
time.
I do find this variable and arbitrary limit a bit confusing, but that's
not your fault - I guess it is an indication that ifnums > 31 are rare
:)
> diff --git a/include/uapi/linux/usbdevice_fs.h
> b/include/uapi/linux/usbdevice_fs.h
> index 019ba1e..9abcb34 100644
> --- a/include/uapi/linux/usbdevice_fs.h
> +++ b/include/uapi/linux/usbdevice_fs.h
> @@ -154,6 +154,10 @@ struct usbdevfs_streams {
> unsigned char eps[0];
> };
>
> +struct usbdevfs_drop_privs {
> + unsigned long interface_allowed_mask;
> +};
> +
"unsigned long" isn't a very good choice here, is it?
Bjørn
