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Bug#898814: When I log in, it hangs until crng init done



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On Fri, 2018-12-14 at 10:24 +0100, Yves-Alexis Perez wrote:
> Something puzzles me with all those issues: as far as I can tell, on most
> install, systemd-random-seed.service should save a seed at shutdown and
> restore it at startup, and this (I think) should be enough to properly init
> the RNG.
> 
> Can you check if the service has been run in your case?

Hi again,

actually don't bother, I was pointed to [1] which has explanations. The random
seed load is done by just writing to /dev/urandom which doesn't  credit
entropy [2].

But there's apparently an RFC [3] for crediting that. It's just a bit
complicated to impose trust on downstream users.

[1] https://bugs.debian.org/912087#118 
[2] 
https://sources.debian.org/src/systemd/239-15/src/random-seed/random-seed.c/#L108
[3] https://github.com/systemd/systemd/pull/10621

I don't have good solutions right now. With 4.19 and if your CPU has an RNG
you're willing to trust, you'll be able to pass random.trust_cpu=yes to the
kernel command line, which should help seeding the RNG.

Regards,
- -- 
Yves-Alexis
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