Re: [PATCH v1 0/6] seccomp: Implement constant action bitmaps

On Thu, Sep 24, 2020 at 02:57:02PM -0400, Andrea Arcangeli wrote:

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:

quoted

rfc: https://lore.kernel.org/lkml/20200616074934.1600036-1-keescook@chromium.org/ (local)
alternative: https://lore.kernel.org/containers/cover.1600661418.git.yifeifz2@illinois.edu/ (local)
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).

quoted

- 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/ (local)

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

?? Because it IS literally Jann's code:
https://lore.kernel.org/lkml/CAG48ez1p=dR_2ikKq=xVxkoGg0fYpTBpkhJSv1w-6BG=76PAvw@mail.gmail.com/ (local)
As the first reply to 20200616074934.1600036-5-keescook@chromium.org. In
June. Which I agreed was the way to go. In June.

And When YiFei Zhu sent their series, I saw they were headed in
a direction that looked functionally similar, but significantly
over-engineered, and done without building on the June RFC and its
discussion. So I raised the priority of putting Jann's code in to the
RFC, so I could send out an update demonstrating both how small I would
like the emulator to be, and how to handle things like x32.

How, exactly, am I not collaborating? I was literally trying to
thread-merge and avoid (more) extra work on YiFei Zhu's end.

-- 
Kees Cook