Re: Excellent job on the firewire support!

At Wed, 21 Jul 2004 15:59:01 +0100,
Doug Rabson wrote:
> > If no, assuming I had a Windows or Linux box on the firewire bus, would it be
> > possible to access physical memory from a different OS?
> 
> Windows XP has some kind of firewire debug driver that you might have to
> load (I haven't read the docs on that). I don't think the linux driver
> enables physical access by default but it would be easy to hack it in
> (just write all ones to the right fwohci register).

The physical access is usually used for SBP-2 initiator mode.
Without physical access, the performance of SBP-2 should be
poorer and we see more load on CPU.

The physical access can be restricted by two way. You can
restrict it per node-id and by physical memory range(upper bound).

As far as I have tried, WindowsXP seems not to allow physical access
of usual nodes. But I think you can easily cheat it by a node with
sbp target mode(use sbp_targ(4) ;-).

In my opinion, it's hard to ensure security with current OHCI
specification. 

https://www.netsecurity.ne.jp/article/2/6202.html

This page describes this problem in Japanese. It says that
information source is "iDEFENSE Intelligence Operations, June 18,
2002" but I cannot find the original source (in English).

/\ Hidetoshi Shimokawa
\/  simokawa_at_sat.t.u-tokyo.ac.jp
PGP public key: http://www.sat.t.u-tokyo.ac.jp/~simokawa/pgp.html