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Date:   Thu, 17 May 2018 16:56:55 -0400
From:   "Theodore Y. Ts'o" <tytso@mit.edu>
To:     Christophe LEROY <christophe.leroy@c-s.fr>
Cc:     Stephan Mueller <smueller@chronox.de>,
        linux-crypto@vger.kernel.org,
        Linux Kernel Developers List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/5] random: fix crng_ready() test
Message-ID: <20180517205655.GC15263@thunk.org>
Mail-Followup-To: "Theodore Y. Ts'o" <tytso@mit.edu>,
        Christophe LEROY <christophe.leroy@c-s.fr>,
        Stephan Mueller <smueller@chronox.de>, linux-crypto@vger.kernel.org,
        Linux Kernel Developers List <linux-kernel@vger.kernel.org>
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On Thu, May 17, 2018 at 08:01:04AM +0200, Christophe LEROY wrote:
> 
> On a powerpc embedded board which has an mpc8xx processor running at 133Mhz,
> I now get the startup done in more than 7 minutes instead of 30 seconds.
> This is due to the webserver blocking on read on /dev/random until we get
> 'random: crng init done':
> 
> [    0.000000] Linux version 4.17.0-rc4-00415-gd2f75d40072d (root@localhost)
> (gcc version 5.4.0 (GCC)) #203 PREEMPT Wed May 16 16:32:02 CEST 2018
> [    0.295453] random: get_random_u32 called from
> bucket_table_alloc+0x84/0x1bc with crng_init=0
> [    1.030472] device: 'random': device_add
> [    1.031279] device: 'urandom': device_add
> [    1.420069] device: 'hw_random': device_add
> [    2.156853] random: fast init done
> [  462.007776] random: crng init done
> 
> This has become really critical, is there anything that can be done ?

Figure out why the webserver needs to read /dev/random and is it for a
security critical purpose?

A kernel patch which makes the kernel do a "lalalalala I'm secure"
when it really isn't secure is a simple "solution", but would it
really make you happy?


						- Ted