From: Stephan Mueller <smueller@chronox.de>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: LKML <linux-kernel@vger.kernel.org>, dave.taht@bufferbloat.net
Subject: Re: [PATCH] /dev/random: Insufficient of entropy on many architectures
Date: Tue, 10 Sep 2013 21:15:31 +0200 [thread overview]
Message-ID: <5317230.pU1YQUx7Id@tauon> (raw)
In-Reply-To: <20130910182524.GE29237@thunk.org>
Am Dienstag, 10. September 2013, 14:25:24 schrieb Theodore Ts'o:
Hi Theodore,
>
>Also note that the clocksource is not necessarily be the best choice;
>it may not be the most fine grained sampling that we have available
>(that is certainly be true for MIPS). So doing something hacky
>doesn't absolve us from the need to example every single platform that
>as a no-op get_cycles() function. (Well, at least those platforms
>that we think really are going to be running security sensitive
>systems ---- does anyone think we really have production systems
>running m68k? Maybe, but....)
That is why I arranged the clocksource call after get_cycles does not
return anything, so it would only be used if get_cycles does not have
anything.
But then, your experience with clocksource really has a point.
>
>If we believed that /dev/random was actually returning numbers which
>are exploitable, because of this, I might agree with the "we must do
>SOMETHING" attitude. But I don't believe this to be the case. Also
>note that we're talking about embedded platforms, where upgrade cycles
>are measured in years --- if you're lucky. There are probably home
>routers still stuck on 2.6, at which point they will be far more
>succeptible to the problems described at http://factorable.net.
The core problem I guess on this matter is again the strange use of
/dev/random in embedded devices -- no seeding, no spinning disks, no
heads, no nothing.
Here my CPU jitter RNG would help, but there seems to be no interest in
even discussing it... PS: I have my CPU jitter RNG running running as an
entropy feeder daemon nicely on my router box, though, which happens to
be a MIPS box...
>
>So I don't think we need to rush. I'd much rather make sure we get
>this fixed right.
>
> - Ted
Ciao
Stephan
next prev parent reply other threads:[~2013-09-10 19:15 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-10 11:31 [PATCH] /dev/random: Insufficient of entropy on many architectures Stephan Mueller
2013-09-10 11:46 ` Geert Uytterhoeven
2013-09-10 15:04 ` Theodore Ts'o
2013-09-10 16:54 ` Stephan Mueller
2013-09-10 18:25 ` Theodore Ts'o
2013-09-10 19:15 ` Stephan Mueller [this message]
2013-10-10 6:50 ` Pavel Machek
2013-10-14 21:13 ` Theodore Ts'o
2013-09-10 20:48 ` Geert Uytterhoeven
2013-09-10 21:14 ` Theodore Ts'o
2013-09-11 6:49 ` Stephan Mueller
2013-09-12 11:59 ` Geert Uytterhoeven
2013-09-12 12:08 ` Stephan Mueller
2013-09-12 12:15 ` Geert Uytterhoeven
2013-09-12 12:35 ` Stephan Mueller
2013-09-12 12:47 ` Geert Uytterhoeven
2013-09-12 12:57 ` Stephan Mueller
2013-09-12 21:18 ` Jörn Engel
2013-09-13 11:33 ` Thorsten Glaser
2013-09-12 14:25 ` Theodore Ts'o
2013-09-10 19:38 ` John Stultz
2013-09-10 19:44 ` John Stultz
2013-09-10 19:47 ` Stephan Mueller
2013-09-10 20:35 ` John Stultz
2013-09-10 20:38 ` Theodore Ts'o
2013-09-10 20:46 ` John Stultz
2013-09-10 21:10 ` Theodore Ts'o
2013-09-10 22:08 ` John Stultz
2013-09-10 22:33 ` Theodore Ts'o
2013-09-11 0:31 ` John Stultz
2013-09-11 0:50 ` Theodore Ts'o
2013-09-11 1:14 ` John Stultz
2013-09-12 20:46 ` H. Peter Anvin
2013-09-12 21:07 ` Jörn Engel
2013-09-12 23:31 ` Theodore Ts'o
2013-09-12 23:35 ` Jörn Engel
2013-09-13 0:00 ` Jörn Engel
2013-09-16 15:40 ` [PATCH,RFC] random: make fast_mix() honor its name Jörn Engel
2013-09-21 21:25 ` Theodore Ts'o
2013-09-21 21:41 ` Theodore Ts'o
2013-09-22 3:05 ` Theodore Ts'o
2013-09-22 21:01 ` Jörg-Volker Peetz
2013-09-22 21:27 ` Theodore Ts'o
2013-09-22 20:53 ` Jörn Engel
2013-09-22 23:36 ` Theodore Ts'o
2013-09-23 0:16 ` Jörn Engel
2013-09-23 2:43 ` Theodore Ts'o
2013-09-23 15:02 ` Jörn Engel
2013-09-23 7:39 ` Jörg-Volker Peetz
2013-09-22 20:31 ` Jörn Engel
2013-09-22 20:14 ` Jörn Engel
2013-09-12 21:31 ` [PATCH] /dev/random: Insufficient of entropy on many architectures Jörn Engel
2013-09-13 5:36 ` Stephan Mueller
2013-09-13 11:54 ` Thorsten Glaser
2013-09-13 19:29 ` Theodore Ts'o
2013-09-13 15:26 ` Jörn Engel
2013-09-13 18:59 ` Theodore Ts'o
2013-09-15 11:12 ` Stephan Mueller
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