From: Steve Grubb <sgrubb@redhat.com>
To: Sandy Harris <sandyinchina@gmail.com>
Cc: Neil Horman <nhorman@redhat.com>, Tomas Mraz <tmraz@redhat.com>,
Sasha Levin <levinsasha928@gmail.com>, "Ted Ts'o" <tytso@mit.edu>,
Jarod Wilson <jarod@redhat.com>,
linux-crypto@vger.kernel.org, Matt Mackall <mpm@selenic.com>,
Herbert Xu <herbert.xu@redhat.com>,
Stephan Mueller <stephan.mueller@atsec.com>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] random: add blocking facility to urandom
Date: Fri, 9 Sep 2011 09:04:17 -0400 [thread overview]
Message-ID: <201109090904.18321.sgrubb@redhat.com> (raw)
In-Reply-To: <CACXcFmnnMLHq2VE35i4QK4wNePXHJc6T73VQNTmJo7WEz34DaQ@mail.gmail.com>
On Thursday, September 08, 2011 10:21:13 PM Sandy Harris wrote:
> > The system being low on entropy is another problem that should be
> > addressed. For our purposes, we cannot say take it from TPM or RDRND or
> > any plugin board. We have to have the mathematical analysis that goes
> > with it, we need to know where the entropy comes from, and a worst case
> > entropy estimation.
>
> Much of that is in the driver code's comments or previous email
> threads. For example,
> this thread cover many of the issues:
> http://yarchive.net/comp/linux/dev_random.html
> There are plenty of others as well.
>
> > It has to be documented in detail.
>
> Yes. But apart from code comments, what documentation
> are we talking about? Googling for /dev/random on tldp.org
> turns up nothing that treats this in any detail.
Thanks for the reply. I see that you are trying to be helpful. But I think you
misunderstand what I was trying to say or maybe I was not entirely clear. We have the
correct analysis for the kernel and it does indeed pass FIPS-140, unaided. We know the
entropy comes from what the minimum entropy estimation is, and quality. (The only
issue is guaranteeing that any seed source must also include entropy.)
But what I was trying to say is that we can't depend on these supplemental hardware
devices like TPM because we don't have access to the proprietary technical details
that would be necessary to supplement the analysis. And when it comes to TPM chips, I
bet each chip has different details and entropy sources and entropy estimations and
rates. Those details we can't get at, so we can't solve the problem by including that
hardware. That is the point I was trying to make. :)
Thanks,
-Steve
next prev parent reply other threads:[~2011-09-09 13:04 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-02 14:37 [PATCH] random: add blocking facility to urandom Jarod Wilson
2011-09-05 2:36 ` Sandy Harris
2011-09-06 14:09 ` Stephan Mueller
2011-09-07 17:38 ` Jarod Wilson
2011-09-07 18:12 ` Sasha Levin
2011-09-07 18:26 ` Jarod Wilson
2011-09-07 19:05 ` Sasha Levin
2011-09-07 19:30 ` Jarod Wilson
2011-09-07 20:00 ` Sasha Levin
2011-09-07 19:35 ` Neil Horman
2011-09-07 19:27 ` Ted Ts'o
2011-09-07 19:36 ` Jarod Wilson
2011-09-07 19:36 ` Jarod Wilson
2011-09-08 2:43 ` Sandy Harris
2011-09-07 19:49 ` David Miller
2011-09-07 20:02 ` Steve Grubb
2011-09-07 20:23 ` Sasha Levin
2011-09-07 20:30 ` Steve Grubb
2011-09-07 20:37 ` Sasha Levin
2011-09-07 20:56 ` Steve Grubb
2011-09-07 21:10 ` Sasha Levin
2011-09-07 21:28 ` Steve Grubb
2011-09-07 21:38 ` Sasha Levin
2011-09-07 21:35 ` Jarod Wilson
2011-09-07 21:43 ` Steve Grubb
2011-09-07 22:46 ` Sven-Haegar Koch
2011-09-08 7:21 ` Sasha Levin
2011-09-07 23:57 ` Neil Horman
2011-09-08 6:41 ` Tomas Mraz
2011-09-08 12:52 ` Neil Horman
2011-09-08 13:11 ` Steve Grubb
2011-09-08 13:49 ` Neil Horman
2011-09-09 2:21 ` Sandy Harris
2011-09-09 13:04 ` Steve Grubb [this message]
2011-09-09 16:25 ` Ted Ts'o
2011-09-09 21:27 ` Thomas Gleixner
2011-09-12 13:56 ` Jarod Wilson
2011-09-13 10:58 ` Peter Zijlstra
2011-09-13 12:18 ` Jarod Wilson
2011-09-11 2:05 ` Valdis.Kletnieks
2011-09-12 13:55 ` Jarod Wilson
2011-09-12 16:58 ` Valdis.Kletnieks
2011-09-12 18:26 ` Jarod Wilson
2011-09-07 20:33 ` Neil Horman
2011-09-07 20:48 ` Steve Grubb
2011-09-07 21:18 ` Ted Ts'o
2011-09-07 21:27 ` Stephan Mueller
2011-09-07 21:27 ` Stephan Mueller
2011-09-07 21:38 ` Ted Ts'o
2011-09-08 8:44 ` Christoph Hellwig
2011-09-08 11:48 ` Steve Grubb
2011-09-08 16:13 ` David Miller
2011-09-09 19:08 ` Eric Paris
2011-09-09 19:12 ` Neil Horman
2011-09-08 8:42 ` Christoph Hellwig
2011-09-08 8:42 ` Christoph Hellwig
2011-09-07 21:20 ` Nikos Mavrogiannopoulos
2011-09-08 8:41 ` Christoph Hellwig
2011-09-12 14:02 ` Jarod Wilson
2011-09-12 14:02 ` Jarod Wilson
2011-09-12 14:58 ` Neil Horman
2011-09-12 17:06 ` Mark Brown
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