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Date:   Thu, 24 Sep 2020 14:57:02 -0400
From:   Andrea Arcangeli <aarcange@redhat.com>
To:     Kees Cook <keescook@chromium.org>
Cc:     YiFei Zhu <yifeifz2@illinois.edu>, Jann Horn <jannh@google.com>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Tycho Andersen <tycho@tycho.pizza>,
        Andy Lutomirski <luto@amacapital.net>,
        Will Drewry <wad@chromium.org>,
        Giuseppe Scrivano <gscrivan@redhat.com>,
        Tobin Feldman-Fitzthum <tobin@ibm.com>,
        Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
        Valentin Rothberg <vrothber@redhat.com>,
        Hubertus Franke <frankeh@us.ibm.com>,
        Jack Chen <jianyan2@illinois.edu>,
        Josep Torrellas <torrella@illinois.edu>,
        Tianyin Xu <tyxu@illinois.edu>, bpf@vger.kernel.org,
        containers@lists.linux-foundation.org, linux-api@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 0/6] seccomp: Implement constant action bitmaps
Message-ID: <20200924185702.GA9225@redhat.com>
References: <20200923232923.3142503-1-keescook@chromium.org>
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Hello,

I'm posting this only for the record, feel free to ignore.

On Wed, Sep 23, 2020 at 04:29:17PM -0700, Kees Cook wrote:
> rfc: https://lore.kernel.org/lkml/20200616074934.1600036-1-keescook@chromium.org/
> alternative: https://lore.kernel.org/containers/cover.1600661418.git.yifeifz2@illinois.edu/
> v1:
> - rebase to for-next/seccomp
> - finish X86_X32 support for both pinning and bitmaps

It's pretty clear the O(1) seccomp filter bitmap was first was
proposed by your RFC in June (albeit it was located in the wrong place
and is still in the wrong place in v1).

> - replace TLB magic with Jann's emulator
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    
That's a pretty fundamental change in v1 compared to your the
non-competing TLB magic technique you used in the RFC last June.

The bitmap isn't the clever part of the patch, the bitmap can be
reviewed in seconds, the difficult part to implement and to review is
how you fill the bitmap and in that respect there's absolutely nothing
in common in between the "rfc:" and the "alternative" link.

In June your bitmap-filling engine was this:

https://lore.kernel.org/lkml/20200616074934.1600036-5-keescook@chromium.org/

Then on Sep 21 YiFei Zhu posted his new innovative BPF emulation
innovation that obsoleted your TLB magic of June:

https://lists.linuxfoundation.org/pipermail/containers/2020-September/042153.html

And on Sep 23 instead of collaborating and helping YiFei Zhu to
improve his BPF emulator, you posted the same technique that looks
remarkably similar without giving YiFei Zhu any attribution and you
instead attribute the whole idea to Jann Horn:

https://lkml.kernel.org/r/20200923232923.3142503-5-keescook@chromium.org

Thanks,
Andrea