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Re: Fixing Linux getrandom() in stable

Cross-posted to 2 groups.

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Am 10.05.2018 um 00:46 schrieb Ben Hutchings:
> 1. Add entropy to the kernel during boot; either:
>    a. Improve systemd-random-seed
>    b. Recommend use of haveged
> 2. For each affected userland package, either:
>    a. Revert to using /dev/urandom
>    b. Tolerate a longer wait for getrandom() to return
> 
> I asked about haveged on Twitter, and got into a discussion with Jann
> Horn (who reported the original issue).  He pointed out that the
> systemd-random-seed service already saves and restores some random data
> between boots.  It currently doesn't tell the RNG that this should be
> treated as adding to available entropy, so it doesn't help to unblock
> getrandom().  It also doesn't fully protect against using the same
> saved data twice, which would be a prerequisite.

There is https://github.com/systemd/systemd/issues/4271 which seems
related. If there is further feedback from our side, this should
probably be added to the upstream bug report.

> The libbsd maintainer (Guillem Jover) favours option 2a.
> 
> One of the krb5 maintainers (Benjamin Kaduk) favours option 2b, and
> also proposed that systemd could provide a wait-for-rng-ready unit to
> support this.

What exactly would such a wait-for-rng-ready service do and how would it
solve this particular problem?

Michael

-- 
Why is it that all of the instruments seeking intelligent life in the
universe are pointed away from Earth?

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Thread

Fixing Linux getrandom() in stable Ben Hutchings <ben@decadent.org.uk> - 2018-05-10 00:50 +0200
  Re: Fixing Linux getrandom() in stable Michael Biebl <biebl@debian.org> - 2018-05-10 15:50 +0200
    Re: Fixing Linux getrandom() in stable Russ Allbery <rra@debian.org> - 2018-05-10 19:30 +0200
      Re: Fixing Linux getrandom() in stable Michael Biebl <biebl@debian.org> - 2018-05-10 19:40 +0200
        Re: Fixing Linux getrandom() in stable Russ Allbery <rra@debian.org> - 2018-05-10 19:50 +0200
          Re: Fixing Linux getrandom() in stable Ian Campbell <ijc@debian.org> - 2018-05-10 21:20 +0200
        Re: Fixing Linux getrandom() in stable Benjamin Kaduk <kaduk@mit.edu> - 2018-05-10 19:50 +0200
  Re: Fixing Linux getrandom() in stable Yves-Alexis Perez <corsac@debian.org> - 2018-05-13 11:30 +0200
    Re: Fixing Linux getrandom() in stable Ben Hutchings <ben@decadent.org.uk> - 2018-05-13 19:20 +0200
  Re: Fixing Linux getrandom() in stable Adrian Bunk <bunk@debian.org> - 2018-05-13 22:50 +0200
    Re: Fixing Linux getrandom() in stable Thorsten Glaser <tg@mirbsd.de> - 2018-05-13 23:40 +0200
      Re: Fixing Linux getrandom() in stable Thorsten Glaser <tg@mirbsd.de> - 2018-05-14 03:00 +0200
      Re: Fixing Linux getrandom() in stable "Theodore Y. Ts'o" <tytso@mit.edu> - 2018-05-14 03:20 +0200
      Re: Fixing Linux getrandom() in stable Sam Hartman <hartmans@debian.org> - 2018-05-14 15:20 +0200
    Re: Fixing Linux getrandom() in stable Ben Hutchings <ben@decadent.org.uk> - 2018-05-14 04:20 +0200
      Re: Fixing Linux getrandom() in stable Adrian Bunk <bunk@debian.org> - 2018-05-22 21:50 +0200

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