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Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in place of MD5

From Hannes Frederic Sowa <hannes@stressinduktion.org>
Newsgroups linux.kernel
Subject Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in place of MD5
Date 2016-12-22 17:00 +0100
Message-ID <sRdWG-2Tv-7@gated-at.bofh.it> (permalink)
References (9 earlier) <sRdai-2C1-21@gated-at.bofh.it> <sRdjY-2Gr-1@gated-at.bofh.it> <sRdtD-2JG-17@gated-at.bofh.it> <sRdDk-2MH-21@gated-at.bofh.it> <sRdN0-2Q5-15@gated-at.bofh.it>
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On Thu, 2016-12-22 at 16:41 +0100, Jason A. Donenfeld wrote:
> Hi Hannes,
> 
> On Thu, Dec 22, 2016 at 4:33 PM, Hannes Frederic Sowa
> <hannes@stressinduktion.org> wrote:
> > IPv6 you cannot touch anymore. The hashing algorithm is part of uAPI.
> > You don't want to give people new IPv6 addresses with the same stable
> > secret (across reboots) after a kernel upgrade. Maybe they lose
> > connectivity then and it is extra work?
> 
> Ahh, too bad. So it goes.

If no other users survive we can put it into the ipv6 module.

> > The bpf hash stuff can be changed during this merge window, as it is
> > not yet in a released kernel. Albeit I would probably have preferred
> > something like sha256 here, which can be easily replicated by user
> > space tools (minus the problem of patching out references to not
> > hashable data, which must be zeroed).
> 
> Oh, interesting, so time is of the essence then. Do you want to handle
> changing the new eBPF code to something not-SHA1 before it's too late,
> as part of a new patchset that can fast track itself to David? And
> then I can preserve my large series for the next merge window.

This algorithm should be a non-seeded algorithm, because the hashes
should be stable and verifiable by user space tooling. Thus this would
need a hashing algorithm that is hardened against pre-image
attacks/collision resistance, which siphash is not. I would prefer some
higher order SHA algorithm for that actually.

Bye,
Hannes

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[PATCH v5 0/4] The SipHash Patchset "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-15 21:40 +0100
  [PATCH v5 4/4] random: use SipHash in place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-15 21:40 +0100
  [PATCH v5 3/4] secure_seq: use SipHash in place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-15 21:40 +0100
    RE: [PATCH v5 3/4] secure_seq: use SipHash in place of MD5 David Laight <David.Laight@ACULAB.COM> - 2016-12-16 11:10 +0100
      Re: [PATCH v5 3/4] secure_seq: use SipHash in place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-16 17:00 +0100
  [PATCH v5 2/4] siphash: add Nu{32,64} helpers "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-15 21:50 +0100
    RE: [PATCH v5 2/4] siphash: add Nu{32,64} helpers David Laight <David.Laight@ACULAB.COM> - 2016-12-16 11:50 +0100
      RE: [PATCH v5 2/4] siphash: add Nu{32,64} helpers "George Spelvin" <linux@sciencehorizons.net> - 2016-12-16 16:50 +0100
  [PATCH v6 4/5] md5: remove from lib and only live in crypto "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-16 04:10 +0100
  [PATCH v6 2/5] secure_seq: use SipHash in place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-16 04:10 +0100
  [PATCH v6 5/5] syncookies: use SipHash in place of SHA1 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-16 04:10 +0100
  [PATCH v6 0/5] The SipHash Patchset "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-16 04:10 +0100
    [PATCH v6 3/5] random: use SipHash in place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-16 04:10 +0100
      Re: [PATCH v6 3/5] random: use SipHash in place of MD5 Andy Lutomirski <luto@amacapital.net> - 2016-12-16 22:40 +0100
    [PATCH v6 1/5] siphash: add cryptographically secure PRF "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-16 04:10 +0100
    [PATCH v7 0/6] The SipHash Patchset "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 00:10 +0100
      [PATCH v7 6/6] siphash: implement HalfSipHash1-3 for hash tables "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 00:10 +0100
        Re: [PATCH v7 6/6] siphash: implement HalfSipHash1-3 for hash tables Andi Kleen <ak@linux.intel.com> - 2016-12-22 01:50 +0100
      [PATCH v7 5/6] syncookies: use SipHash in place of SHA1 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 00:10 +0100
      [PATCH v7 3/6] random: use SipHash in place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 00:10 +0100
        Re: [PATCH v7 3/6] random: use SipHash in place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 00:20 +0100
        Re: [PATCH v7 3/6] random: use SipHash in place of MD5 Andy Lutomirski <luto@amacapital.net> - 2016-12-22 01:00 +0100
          Re: [PATCH v7 3/6] random: use SipHash in place of MD5 Hannes Frederic Sowa <hannes@stressinduktion.org> - 2016-12-22 03:10 +0100
            Re: [PATCH v7 3/6] random: use SipHash in place of MD5 Andy Lutomirski <luto@amacapital.net> - 2016-12-22 03:20 +0100
            Re: [PATCH v7 3/6] random: use SipHash in place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 03:50 +0100
              Re: [PATCH v7 3/6] random: use SipHash in place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 04:20 +0100
              Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 Theodore Ts'o <tytso@mit.edu> - 2016-12-22 06:50 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 07:10 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 Theodore Ts'o <tytso@mit.edu> - 2016-12-22 17:00 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 17:20 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 Theodore Ts'o <tytso@mit.edu> - 2016-12-22 17:40 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 17:40 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 Hannes Frederic Sowa <hannes@stressinduktion.org> - 2016-12-22 13:50 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 14:20 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 Hannes Frederic Sowa <hannes@stressinduktion.org> - 2016-12-22 16:10 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 16:20 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 16:30 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 Hannes Frederic Sowa <hannes@stressinduktion.org> - 2016-12-22 16:40 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 16:50 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 Hannes Frederic Sowa <hannes@stressinduktion.org> - 2016-12-22 17:00 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 17:00 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 Theodore Ts'o <tytso@mit.edu> - 2016-12-22 17:00 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 Hannes Frederic Sowa <hannes@stressinduktion.org> - 2016-12-22 19:10 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 19:20 +0100
                Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in  place of MD5 Theodore Ts'o <tytso@mit.edu> - 2016-12-22 21:00 +0100
          Re: [PATCH v7 3/6] random: use SipHash in place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 03:40 +0100
      [PATCH v7 4/6] md5: remove from lib and only live in crypto "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 00:10 +0100
      [PATCH v7 2/6] secure_seq: use SipHash in place of MD5 "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 00:10 +0100
      [PATCH v7 1/6] siphash: add cryptographically secure PRF "Jason A. Donenfeld" <Jason@zx2c4.com> - 2016-12-22 00:10 +0100
        Re: [PATCH v7 1/6] siphash: add cryptographically secure PRF Stephen Hemminger <stephen@networkplumber.org> - 2016-12-22 02:50 +0100

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