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Date: Wed, 21 Jul 2004 11:04:17 -0400 (EDT)
To: Doug Rabson <dfr@nlsystems.com>
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cc: simokawa@freebsd.org
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Subject: Re: Excellent job on the firewire support!
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Doug Rabson writes:
 > On Wed, 2004-07-21 at 15:41, Andrew Gallatin wrote:
 > > Doug Rabson writes:
 > >  > Actually thats the only downside of dcons. It doesn't cut in until the 
 > >  > firewire controller attaches. It relies on the fact that the fwohci 
 > >  > driver allows access to physical memory from any node on the bus 
 > >  > (implemeted in hardware so you can examine the memory of a hung 
 > >  > machine). The dconschat program uses this feature to access the dcons 
 > >  > ring buffers in the target machine.
 > > 
 > > Does remote access to physical memory require dcons to be loaded
 > > on the target?
 > 
 > No. The remote access to physical memory is a hardware-implemented
 > feature of the firewire ohci hardware. Its enabled in fwohci_attach().
 > In the long term, I would like to restrict this a bit but right now all
 > you have to have is fwohci loaded on the target machine.

Yes, it seems like turning it off by default would be a good idea.
Its very handy for debugging, but the security implications are rather
alarming..

Thanks for the info!

Drew