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Date:   Wed, 30 Sep 2020 15:53:55 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Jann Horn <jannh@google.com>
Cc:     YiFei Zhu <zhuyifei1999@gmail.com>,
        Linux Containers <containers@lists.linux-foundation.org>,
        YiFei Zhu <yifeifz2@illinois.edu>, bpf <bpf@vger.kernel.org>,
        kernel list <linux-kernel@vger.kernel.org>,
        Aleksa Sarai <cyphar@cyphar.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Andy Lutomirski <luto@amacapital.net>,
        David Laight <David.Laight@aculab.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>,
        Tycho Andersen <tycho@tycho.pizza>,
        Valentin Rothberg <vrothber@redhat.com>,
        Will Drewry <wad@chromium.org>
Subject: Re: [PATCH v3 seccomp 1/5] x86: Enable seccomp architecture tracking
Message-ID: <202009301549.17D3DE5@keescook>
References: <cover.1601478774.git.yifeifz2@illinois.edu>
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On Wed, Sep 30, 2020 at 11:33:15PM +0200, Jann Horn wrote:
> On Wed, Sep 30, 2020 at 11:21 PM Kees Cook <keescook@chromium.org> wrote:
> > On Wed, Sep 30, 2020 at 10:19:12AM -0500, YiFei Zhu wrote:
> > > From: Kees Cook <keescook@chromium.org>
> > >
> > > Provide seccomp internals with the details to calculate which syscall
> > > table the running kernel is expecting to deal with. This allows for
> > > efficient architecture pinning and paves the way for constant-action
> > > bitmaps.
> > >
> > > Signed-off-by: Kees Cook <keescook@chromium.org>
> > > [YiFei: Removed x32, added macro for nr_syscalls]
> > > Signed-off-by: YiFei Zhu <yifeifz2@illinois.edu>
> [...]
> > But otherwise, yes, looks good to me. For this patch, I think the S-o-b chain is probably more
> > accurately captured as:
> >
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > Co-developed-by: YiFei Zhu <yifeifz2@illinois.edu>
> > Signed-off-by: YiFei Zhu <yifeifz2@illinois.edu>
> 
> (Technically, https://www.kernel.org/doc/html/latest/process/submitting-patches.html#when-to-use-acked-by-cc-and-co-developed-by
> says that "every Co-developed-by: must be immediately followed by a
> Signed-off-by: of the associated co-author" (and has an example of how
> that should look).)

Right, but it is not needed for the commit author (here, the From:),
the second example given in the docs shows this:

	From: From Author <from@author.example.org>

	<changelog>

	Co-developed-by: Random Co-Author <random@coauthor.example.org>
	Signed-off-by: Random Co-Author <random@coauthor.example.org>
	Signed-off-by: From Author <from@author.example.org>
	Co-developed-by: Submitting Co-Author <sub@coauthor.example.org>
	Signed-off-by: Submitting Co-Author <sub@coauthor.example.org>

and there is no third co-developer, so it's:

	From: From Author <from@author.example.org>

	<changelog>

	Signed-off-by: From Author <from@author.example.org>
	Co-developed-by: Submitting Co-Author <sub@coauthor.example.org>
	Signed-off-by: Submitting Co-Author <sub@coauthor.example.org>

If I'm the From, and YiFei Zhu is the submitting co-developer, then
it's:

	From: Kees Cook <keescook@chromium.org>

	<changelog>

	Signed-off-by: Kees Cook <keescook@chromium.org>
	Co-developed-by: YiFei Zhu <yifeifz2@illinois.edu>
	Signed-off-by: YiFei Zhu <yifeifz2@illinois.edu>

which is what I suggested.

-- 
Kees Cook