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From:   YiFei Zhu <zhuyifei1999@gmail.com>
Date:   Mon, 21 Sep 2020 19:47:40 -0500
Message-ID: <CABqSeARpj-wRzS_bbfeD8=6LOQ64mdQR6DS5O2fSmCDTduFLGg@mail.gmail.com>
Subject: Re: [RFC PATCH seccomp 1/2] seccomp/cache: Add "emulator" to check if
 filter is arg-dependent
To:     Jann Horn <jannh@google.com>
Cc:     Kees Cook <keescook@chromium.org>,
        Linux Containers <containers@lists.linux-foundation.org>,
        YiFei Zhu <yifeifz2@illinois.edu>, bpf <bpf@vger.kernel.org>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
        Giuseppe Scrivano <gscrivan@redhat.com>,
        Hubertus Franke <frankeh@us.ibm.com>,
        Jack Chen <jianyan2@illinois.edu>,
        Josep Torrellas <torrella@illinois.edu>,
        Tianyin Xu <tyxu@illinois.edu>,
        Tobin Feldman-Fitzthum <tobin@ibm.com>,
        Valentin Rothberg <vrothber@redhat.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Will Drewry <wad@chromium.org>,
        Aleksa Sarai <cyphar@cyphar.com>,
        kernel list <linux-kernel@vger.kernel.org>
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On Mon, Sep 21, 2020 at 7:26 PM Jann Horn <jannh@google.com> wrote:
> > In the initial RFC patch I only added to x86. I could add it to any
> > arch that has seccomp filters. Though, I'm wondering, why is SECCOMP
> > in the arch-specific Kconfigs?
>
> Ugh, yeah, the existing code is already bad... as far as I can tell,
> SECCOMP shouldn't be there, and instead the arch-specific Kconfig
> should define something like HAVE_ARCH_SECCOMP and then arch/Kconfig
> would define SECCOMP and let it depend on HAVE_ARCH_SECCOMP. It's
> really gross how the SECCOMP config description has been copypasted
> into a dozen different Kconfig files; and looking around a bit, you
> can actually see that e.g. s390 has an utterly outdated help text
> which still claims that seccomp is controlled via the ancient
> "/proc/<pid>/seccomp". I guess this very nicely illustrates why
> putting such options into arch-specific Kconfig is a bad idea. :P

Ah, time to fix this then.

YiFei Zhu