Subject: Re: bug#23605: /dev/urandom not seeded across reboots

From: "Thompson, David" <[email-masked]>
Date: Tue, 24 May 2016 12:26:29 -0400

On Tue, May 24, 2016 at 12:16 PM, Leo Famulari <[email-masked]> wrote:
> On Tue, May 24, 2016 at 09:05:21AM +0200, Taylan Ulrich Bayırlı/Kammer wrote:
>> Leo Famulari <[email-masked]> writes:
>> > Does anyone have advice about the service? Am I wrong that we need to
>> > seed /dev/urandom to make it work properly?
>>
>> Yes, this is necessary under Linux if you want urandom to be random
>> enough immediately after boot, and all the distros do it as part of
>> their init.
>>
>> There's also an interesting implication here about the very first time
>> you boot the system and don't have a urandom seed file from the last
>> shutdown yet.  I don't know how this is typically handled, given that
>> for instance it's quite possible that a user might generate SSH keys
>> shortly after their first boot of a system.
>
> When I boot a GuixSD VM for the first time [0], it requires me to dance
> on the keyboard until it has collected ~200 bits of entropy. I assumed
> this is to properly bootstrap the CSPRNG in /dev/urandom, but I'm not
> sure.

This is just an annoying feature of GNU lsh.  I want to switch my
machines to OpenSSH sometime, partly due to this.

- Dave