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References: <20220304172852.274126-1-benjamin.tissoires@redhat.com> <20220304172852.274126-2-benjamin.tissoires@redhat.com>
In-Reply-To: <20220304172852.274126-2-benjamin.tissoires@redhat.com>
From:   Song Liu <song@kernel.org>
Date:   Fri, 4 Mar 2022 15:12:14 -0800
Message-ID: <CAPhsuW4otgwwDN6+xcjPXmZyUDiynEKFtXjaFb-=kjz7HzUmZw@mail.gmail.com>
Subject: Re: [PATCH bpf-next v2 01/28] bpf: add new is_sys_admin_prog_type() helper
To:     Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc:     Greg KH <gregkh@linuxfoundation.org>,
        Jiri Kosina <jikos@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>, Shuah Khan <shuah@kernel.org>,
        Dave Marchevsky <davemarchevsky@fb.com>,
        Joe Stringer <joe@cilium.io>,
        Tero Kristo <tero.kristo@linux.intel.com>,
        open list <linux-kernel@vger.kernel.org>,
        "open list:HID CORE LAYER" <linux-input@vger.kernel.org>,
        Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
        linux-kselftest@vger.kernel.org, Sean Young <sean@mess.org>
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On Fri, Mar 4, 2022 at 9:30 AM Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
>
> LIRC_MODE2 does not really need net_admin capability, but only sys_admin.
>
> Extract a new helper for it, it will be also used for the HID bpf
> implementation.
>
> Cc: Sean Young <sean@mess.org>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
>
> ---
>
> new in v2
> ---
>  kernel/bpf/syscall.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index db402ebc5570..cc570891322b 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -2165,7 +2165,6 @@ static bool is_net_admin_prog_type(enum bpf_prog_type prog_type)
>         case BPF_PROG_TYPE_LWT_SEG6LOCAL:
>         case BPF_PROG_TYPE_SK_SKB:
>         case BPF_PROG_TYPE_SK_MSG:
> -       case BPF_PROG_TYPE_LIRC_MODE2:
>         case BPF_PROG_TYPE_FLOW_DISSECTOR:
>         case BPF_PROG_TYPE_CGROUP_DEVICE:
>         case BPF_PROG_TYPE_CGROUP_SOCK:
> @@ -2202,6 +2201,17 @@ static bool is_perfmon_prog_type(enum bpf_prog_type prog_type)
>         }
>  }
>
> +static bool is_sys_admin_prog_type(enum bpf_prog_type prog_type)
> +{
> +       switch (prog_type) {
> +       case BPF_PROG_TYPE_LIRC_MODE2:
> +       case BPF_PROG_TYPE_EXT: /* extends any prog */
> +               return true;
> +       default:
> +               return false;
> +       }
> +}

I am not sure whether we should do this. This is a behavior change, that may
break some user space. Also, BPF_PROG_TYPE_EXT is checked in
is_perfmon_prog_type(), and this change will make that case useless.

Thanks,
Song

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