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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Mon, 16 Nov 2020 15:00:09 -0800
Message-ID: <CAADnVQ+6zXX0V8Qn7VOrdgcVVjgbyTEguAKpqkwvW4b3spSHYw@mail.gmail.com>
Subject: Re: [PATCH bpf-next 1/2] bpf: Add bpf_lsm_set_bprm_opts helper
To:     KP Singh <kpsingh@chromium.org>
Cc:     Daniel Borkmann <daniel@iogearbox.net>,
        open list <linux-kernel@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Paul Turner <pjt@google.com>,
        Pauline Middelink <middelin@google.com>
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On Mon, Nov 16, 2020 at 2:48 PM KP Singh <kpsingh@chromium.org> wrote:
>
> [...]
>
> > >
> > > +BPF_CALL_2(bpf_lsm_set_bprm_opts, struct linux_binprm *, bprm, u64, flags)
> > > +{
> >
> > This should also reject invalid flags. I'd rather change this helper from RET_VOID
> > to RET_INTEGER and throw -EINVAL for everything other than BPF_LSM_F_BPRM_SECUREEXEC
> > passed in here including zero so it can be extended in future.
>
> Sounds good, I added:
>
>  enum {
>         BPF_LSM_F_BPRM_SECUREEXEC       = (1ULL << 0),
> +       /* Mask for all the currently supported BPRM options */
> +       BPF_LSM_F_BRPM_OPTS_MASK        = 0x1ULL,
>  };

No need to add it to uapi.
Keep it next to the helper in .c file like it's done with other flags.