Re: [PATCH bpf-next v1 1/6] HID: initial BPF implementation

[Benjamin Tissoires <benjamin.tissoires@redhat.com>]

On Thu, Feb 24, 2022 at 12:41 PM Greg KH <greg@kroah.com> wrote:
>
> On Thu, Feb 24, 2022 at 12:08:23PM +0100, Benjamin Tissoires wrote:
> > index 000000000000..243ac45a253f
> > --- /dev/null
> > +++ b/include/uapi/linux/bpf_hid.h
> > @@ -0,0 +1,39 @@
> > +/* SPDX-License-Identifier: GPL-2.0-or-later WITH Linux-syscall-note */
> > +
> > +/*
> > + *  HID BPF public headers
> > + *
> > + *  Copyright (c) 2021 Benjamin Tissoires
> > + */
> > +
> > +#ifndef _UAPI__LINUX_BPF_HID_H__
> > +#define _UAPI__LINUX_BPF_HID_H__
> > +
> > +#include <linux/types.h>
> > +
> > +#define HID_BPF_MAX_BUFFER_SIZE              16384           /* 16kb */
> > +
> > +struct hid_device;
> > +
> > +enum hid_bpf_event {
> > +     HID_BPF_UNDEF = 0,
> > +     HID_BPF_DEVICE_EVENT,
> > +};
> > +
> > +/* type is HID_BPF_DEVICE_EVENT */
> > +struct hid_bpf_ctx_device_event {
> > +     __u8 data[HID_BPF_MAX_BUFFER_SIZE];
> > +     unsigned long size;
>
> That's not a valid type to cross the user/kernel boundry, shouldn't it
> be "__u64"?  But really, isn't __u32 enough here?

thanks. Even __u16 should be enough, given that the upper bound is
16384. I'll amend it in v2.

Cheers,
Benjamin

>
> thanks,
>
> greg k-h
>