Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 16 May 2005 21:47:33 +0200
From:      "Poul-Henning Kamp" <phk@phk.freebsd.dk>
To:        Colin Percival <cperciva@freebsd.org>
Cc:        Nate Lawson <nate@root.org>
Subject:   Re: cvs commit: src/sys/amd64/amd64 mp_machdep.c src/sys/amd64/include cpufunc.h src/sys/i386/i386 mp_machdep.c src/sys/i386/include cpufunc.h 
Message-ID:  <1976.1116272853@critter.freebsd.dk>
In-Reply-To: Your message of "Sun, 15 May 2005 16:29:32 EDT." <4287B12C.9080903@freebsd.org> 

next in thread | previous in thread | raw e-mail | index | archive | help
In message <4287B12C.9080903@freebsd.org>, Colin Percival writes:
>Nate Lawson wrote:
>> Every general-purpose machine has measurable timing side channels.  The
>> question is merely one of bandwidth.
>
>Absolutely.  Most covert channels operate at up to a few kbps; this covert
>channel operates at several Mbps.

Not only that, but the measurement precision is much better than for more
indirect inspection methods like ps(1).

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?1976.1116272853>