Re: [dsfjdssdfsd] Risks of entropy available

Theodore Ts'o <tytso@mit.edu> Thu, 11 January 2018 22:49 UTC

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Date: Thu, 11 Jan 2018 17:49:53 -0500
From: Theodore Ts'o <tytso@mit.edu>
To: Dan Brown <danibrown@blackberry.com>
Cc: "dsfjdssdfsd@ietf.org" <dsfjdssdfsd@ietf.org>
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Subject: Re: [dsfjdssdfsd] Risks of entropy available
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On Thu, Jan 11, 2018 at 08:19:30PM +0000, Dan Brown wrote:
> 
> If an adversary gains access to this interface, then there is a
> small risk that sensitive information leaks to the adversary,
> because the entropy estimate may be derived from and correlated to
> sensitive information.

I'll note that most of the entropy is coming from interrupt timing,
and we use timing from many interrupts for a single bit.  One can get
more information about what is going on with the system using
/proc/interrupts.  You'll get far more detail about keyboard timings
from /proc/interrupts.

You can also find out what's happening with incoming network packets
using ifconfig.... and then there's vmstat, iostat, ps, etc., etc.

So there's quite a lot of system interfaces one would have to restrict
before I would even *start* worrying about the entropy count.

Regards,

						- Ted