Re: entropy at stage 1

From: Rasmus Villemoes <>
Date: Wed, 27 Sep 2017 09:36:15 +0200

On 2017-09-26 18:20, Jorge Almeida wrote:
> This is what I do at stage 1, regarding entropy gathering:

Thanks, but nothing short of an ioctl(RNDADDTOENTCNT) or
ioctl(RNDADDENTROPY) will the change the kernel's measure of the
gathered entropy, and to use those in good conscience obviously requires
actually saving a seed across reboots, something which is not very
easily achievable in my case. But if I can't convince Laurent to not
rely on getrandom() in s6-rc-update I'll either have to try that, or
(more likely) just change getrandom: yes to getrandom: no in the sysdeps.

> - start haveged service soon
> - in background,
> - read 512 bytes from /dev/random and write them to /dev/urandom
> - write something to a pipe entropy_pipe
> -meanwhile, do other stuff (filesystem checking, etc)
> -in background,
> -read from entropy_pipe (blocks until ready)
> - start services that require /dev/urandom in a sane state

The two processes with an entropy_pipe between them seems overkill, why
not just have one process do getrandom(,,0)?

> To my experience (common 1 user workstations) startup is very fast (1
> or 2 secs).

Yes, but this is far from a common user workstation.

Rasmus Villemoes
Software Developer
Prevas A/S
Hedeager 1
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Received on Wed Sep 27 2017 - 07:36:15 UTC

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