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Subject: Re: [PATCH bpf-next v5 5/7] bpf: lsm: Initialize the BPF LSM hooks
To:     Kees Cook <keescook@chromium.org>
Cc:     KP Singh <kpsingh@chromium.org>, linux-kernel@vger.kernel.org,
        linux-security-module@vger.kernel.org,
        Brendan Jackman <jackmanb@google.com>,
        Florent Revest <revest@google.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        James Morris <jmorris@namei.org>, Paul Turner <pjt@google.com>,
        Jann Horn <jannh@google.com>,
        Florent Revest <revest@chromium.org>,
        Brendan Jackman <jackmanb@chromium.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Casey Schaufler <casey@schaufler-ca.com>
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From:   Casey Schaufler <casey@schaufler-ca.com>
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Date:   Mon, 23 Mar 2020 16:39:35 -0700
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On 3/23/2020 3:12 PM, Kees Cook wrote:
> On Mon, Mar 23, 2020 at 02:58:18PM -0700, Casey Schaufler wrote:
>> That's not too terrible, I suppose. What would you be thinking for
>> the calls that do use call_int_hook()?
>>
>> 	rc =3D call_int_hook(something, something_default, goodnesses);
>>
>> or embedded in the macro:
>>
>> 	rc =3D call_int_hook(something, goodnesses);
> Oh yes, good point. The hook call already knows the name, so:
>
> #define call_int_hook(FUNC, ...) ({                        \
>         int RC =3D FUNC#_default;                            \
> ...

That makes the most sense, I think. It's getting a little heavy on
hidden magic, but we do tend to have a pretty good set of eyes watching
when a new hook is proposed. I would expect the changes to call_int_hook(=
)
and its callers should be made when default is added to LSM_HOOK, not
after.