From: John Gilmore <gnu@toad.com>
Date: Sat, 13 Jan 1996 18:09:40 +0800
To: gnu@toad.com
Subject: Re: Shimomura on BPF, NSA and Crypto
Message-ID: <9601130957.AA19298@toad.com>
MIME-Version: 1.0
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Tsutomu says the NSA is inept rather than inherently evil.  I think he
concluded this because they declined to fund his work.  An ept and
evil NSA would want Tsutomu on the payroll.

Tsutomu's stealth version of the Berkeley packet filter did a lot more
than modload into the kernel.  He was paid by the Air Force to design
one that could patch itself into SunOS kernels invisibly, even into
kernels with no modload support at all.  It had special code that
would search through the kernel binary for references to the address
of the Ethernet chip, and patch itself in during the very low level
interrupt handling.  It was highly optimized so it wouldn't show up by
loading down the machine, and it did things like decrement the
interrupt counter so that even the extra interrupts caused by running
the Ethernet chip in 'receive every packet on the wire' mode wouldn't
be visible.  He talked about enhancements that would automatically
forward packets of interest back out onto the Internet, so the whole
shebang would hide in kernel memory, never visible to users, never
running any processes or altering any files.  Think of it as Digital
Telephony wiretap technology for the Internet.

The idea was to design something that you could run on a machine
without the owner ever finding out about it.  To break into that
person's network.  It's a tool customized for crackers.  It's one
of the tools that Mitnick was after when he broke into Tsutomu's
machine.

Tsutomu actually wrote and ran this stealth BPF code (as well as
designing it) and got into a tiff with the Air Force.  They wanted the
code, not just the design paper they'd commissioned.  He countered by
offering to post the code to the net, with a copyright that let anyone
EXCEPT the government use it, if they wouldn't pay him for the paper.
I don't know how the situation was eventually resolved.

Tsutomu has lots of glib rhetoric about how he just builds tools and
they can be used for good or evil.  This tool is custom-designed for
evil.  Maybe in wartime the Air Force will want to inflict evil on an
opponent.  Or maybe instead they'll pass it to a latter-day J. Edgar
Hoover.  Either way, it's evil.  It doesn't become good when you
inflict it on someone you dislike.
-- 
John Gilmore                                    gnu@toad.com  --  gnu@eff.org
        Don't introduce that Tsutomu to your girlfriend.