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Re: regarding the changes to kernel entropy gathering



At Tue, 6 Apr 2021 20:21:43 +0200, Martin Husemann <martin%duskware.de@localhost> wrote:
Subject: Re: regarding the changes to kernel entropy gathering
>
> On Tue, Apr 06, 2021 at 10:54:51AM -0700, Greg A. Woods wrote:
> >
> > And the stock implementation has no possibility of ever providing an
> > initial seed at all on its own (unlike previous implementations, and of
> > course unlike what my patch _affords_).
>
> Isn't it as simple as:
>
> 	dd bs=32 if=/dev/urandom of=/dev/random

No, that still leaves the question of _when_ to run it.  (And, at least
at the moment, where to put it.  /etc/rc.local?)

Isn't something the following better (assuming you choose your devices
carefully):

	echo 'rndctl_flags="-t env;-t disk;-t tty"' >> /etc/rc.conf

That's what my patches fix and allow, and this way you don't have to
guess when you can safely use /dev/urandom as an entropy seed -- the
seeding happens in real time, and only as entropy bits are made
available from those given devices.

That can also be done by sysinst, assuming a reasonably well worded
question can be answered, and that it might only need to be asked if
there are no "rng" type devices already.

Doing this also requires no network access (ever).

It can even be done, ahead of time, for use on immutable systems.

--
					Greg A. Woods <gwoods%acm.org@localhost>

Kelowna, BC     +1 250 762-7675           RoboHack <woods%robohack.ca@localhost>
Planix, Inc. <woods%planix.com@localhost>     Avoncote Farms <woods%avoncote.ca@localhost>

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