linux-kernel - Re: [PATCH v4 0/6] Seeding DRBG with more entropy

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Message-ID: <20150504061350.GA25540@gondor.apana.org.au>
Date:	Mon, 4 May 2015 14:13:51 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Stephan Mueller <smueller@...onox.de>
Cc:	Theodore Ts'o <tytso@....edu>, Paul Bolle <pebolle@...cali.it>,
	Andreas Steffen <andreas.steffen@...ongswan.org>,
	Sandy Harris <sandyinchina@...il.com>,
	linux-kernel@...r.kernel.org, linux-crypto@...r.kernel.org
Subject: Re: [PATCH v4 0/6] Seeding DRBG with more entropy

On Mon, May 04, 2015 at 07:40:12AM +0200, Stephan Mueller wrote:
> 
> I am not sure that this approach is helpful, because the suggested approach 
> implies using a seeded DRNG and the used get_random_bytes already operates as 
> a (not always seeded) DRNG. If we have a blocking interface in the kernel, I 
> would recommend to make it identical to /dev/random. With the suggested 
> seeding approach for DRBG, we definitely have seed data available to start 
> with. Therefore, re-seeding it from another seeded DRNG (i.e. the nonblocking 
> pool after it is initialized) may not give us too much extra.

My main concern with your original approach was precisely the
fact that get_random_bytes may be called before the before the
kernel pool is ready.  So Ted's solution solves that perfectly.

Please do what Ted says and we can all move forward.

Thanks!
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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