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From:   YiFei Zhu <zhuyifei1999@gmail.com>
Date:   Thu, 24 Sep 2020 03:07:23 -0500
Message-ID: <CABqSeARV4prXOWf9qOBnm5Mm_aAdjwquqFFLQSuL0EegqeWEkA@mail.gmail.com>
Subject: Re: [PATCH 3/6] seccomp: Implement constant action bitmaps
To:     Kees Cook <keescook@chromium.org>
Cc:     Jann Horn <jannh@google.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Giuseppe Scrivano <gscrivan@redhat.com>,
        Will Drewry <wad@chromium.org>, bpf <bpf@vger.kernel.org>,
        YiFei Zhu <yifeifz2@illinois.edu>,
        Linux API <linux-api@vger.kernel.org>,
        Linux Containers <containers@lists.linux-foundation.org>,
        Tobin Feldman-Fitzthum <tobin@ibm.com>,
        Hubertus Franke <frankeh@us.ibm.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Valentin Rothberg <vrothber@redhat.com>,
        Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
        Jack Chen <jianyan2@illinois.edu>,
        Josep Torrellas <torrella@illinois.edu>,
        Tianyin Xu <tyxu@illinois.edu>,
        kernel list <linux-kernel@vger.kernel.org>
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On Thu, Sep 24, 2020 at 2:37 AM Kees Cook <keescook@chromium.org> wrote:
> >
> > This belongs over into patch 1.
>
> Thanks! I was rushing to get this posted so YiFei Zhu wouldn't spend
> time fighting with arch and Kconfig stuff. :) I'll clean this (and the
> other random cruft) up.

Wait, what? I'm sorry. We have already begun fixing the mentioned
issues (mostly the split bitmaps for different arches). Although yes
it's nice to have another implementation to refer to so we get the
best of both worlds (and yes I'm already copying some of the code I
think are better here over there), don't you think it's not nice to
say "Hey I've worked on this in June, it needed rework but I didn't
send the newer version. Now you sent yours so I'll rush mine so your
work is redundant."?

That said, I do think this should be configurable. Users would be free
to experiment with the bitmap on or off, just like users may turn
seccomp off entirely. A choice also allows users to select different
implementations, a few whom I work with have ideas on how to
accelerate / cache argument dependent syscalls, for example.

YiFei Zhu