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From: Sam Lawrance <boris@brooknet.com.au>
To: Colin Percival <cperciva@freebsd.org>
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Date: Sun, 22 May 2005 15:02:50 +1000
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cc: Marcel Moolenaar <marcel@xcllnt.net>
Subject: Re: Scheduler fixes for hyperthreading
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On Sat, 2005-05-21 at 21:35 -0700, Colin Percival wrote:
> Marcel Moolenaar wrote:
> > There are a lot of variables that need to be taken into account and
> > those variables do not necessarily map perfectly from a P4 to an I2.
> > Sharing of the L1 cache is not a sufficient condition to create a
> > side-channel for timing attacks. A reliable time source with enough
> > precision is also necessary (as you and Stephan have pointed out).
> > The precision of the time source depends on latencies of the various
> > cache levels and the micro-architectural behavior of the processor.
> 
> Point taken.  I maintain, however, that it is much better to make
> "information can leak between these processors" a machine-independent
> concept which is handled appropriately by the scheduler (with the
> necessary machine-dependent code to specify *which* sets of processors,
> if any, have such leakage).

I'm just curious here... would the mac_seeotheruids policy help in
obscuring the value of any information collected by a spy process?