> On Fri, 21 Jul 2000, Mark Murray wrote:
> > Section 2.1, last paragraph:
> > "If a system is shut down, and restarted, it is desirable to store some
> > high-entropy data (such as the key) in non-volatile memory. This allows
> > the PRNG to be restarted in an unguessable state at the next restart. We
> > call this data the reseed file."
> I'm all for storing a sample at shutdown and using it to help seed the
> PRNG at startup, but it shouldn't be the only seed used (for example, the
> case where the system has never been shut down (cleanly) before and so has
> no pre-existing seed file is a BIG corner case to consider since thats how
> the system is at the time it first generates SSH keys after a fresh
> install).
> It might be only an academic vulnerability, but if someone can read your
> HD during the time the system is shut down then I'd prefer them not to
> know the precise state when the system next starts up again. Yes, if they
> can read they can probably also write, but it seems like a mistake when
> there's nothing really gained by saving the complete state, as opposed to
> an extract.

And for folks like us who do mass installs via dd if=/dev/da1 of=/dev/da2,
where da1 is a mastered image created via ``make installworld DESTDIR=/mnt'',
the corner case is very large.  I have been bitten by an event where the
master disk was booted once before replication, and thus all systems
had _IDENTICAL_ /etc/ssh contents.  Not a very good idea !!

We have amended the manufacturing process now, so that part of the
disk replication is the nuking and regeneration of /etc/ssh.

Rod Grimes - KD7CAX @ CN85sl - (RWG25)               [EMAIL PROTECTED]

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