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

From "Jason A. Donenfeld" <Jason@zx2c4.com>
Newsgroups linux.kernel
Subject Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in place of MD5
Date 2016-12-22 07:10 +0100
Message-ID <sR4JH-5Az-7@gated-at.bofh.it> (permalink)
References (2 earlier) <sQYbg-1hM-43@gated-at.bofh.it> <sQYXD-1An-7@gated-at.bofh.it> <sR0Zr-32l-1@gated-at.bofh.it> <sR1C9-3eC-5@gated-at.bofh.it> <sR4qm-5dV-33@gated-at.bofh.it>
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Hi Ted,

On Thu, Dec 22, 2016 at 6:41 AM, Theodore Ts'o <tytso@mit.edu> wrote:
> The bottom line is that I think we're really "pixel peeping" at this
> point --- which is what obsessed digital photographers will do when
> debating the quality of a Canon vs Nikon DSLR by blowing up a photo by
> a thousand times, and then trying to claim that this is visible to the
> human eye.  Or people who obsessing over the frequency response curves
> of TH-X00 headphones with Mahogony vs Purpleheart wood, when it's
> likely that in a blind head-to-head comparison, most people wouldn't
> be able to tell the difference....

This is hilarious, thanks for the laugh. I believe you're right about this...

>
> I think the main argument for using the batched getrandom approach is
> that it, I would argue, simpler than introducing siphash into the
> picture.  On 64-bit platforms it is faster and more consistent, so
> it's basically that versus complexity of having to adding siphash to
> the things that people have to analyze when considering random number
> security on Linux.   But it's a close call either way, I think.

I find this compelling. We'll have one csprng for both
get_random_int/long and for /dev/urandom, and we'll be able to update
that silly warning on the comment of get_random_int/long to read
"gives output of either rdrand quality or of /dev/urandom quality",
which makes it more useful for other things. It introduces less error
prone code, and it lets the RNG analysis be spent on just one RNG, not
two.

So, with your blessing, I'm going to move ahead with implementing a
pretty version of this for v8.

Regards,
Jason

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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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