Re: Excellent job on the firewire support!

From: Julian Elischer <julian_at_elischer.org>
Date: Fri, 23 Jul 2004 12:14:07 -0700
How about setting it up to read the screen buffer during boot..


Maxim Sobolev wrote:

> Doug Rabson wrote:
>
>> 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.
>
>
> It would be nice to have some sysctl which to disable such access, 
> since it is BAD THING[tm] from the security POV.
>
> -Maxim
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Received on Fri Jul 23 2004 - 17:14:08 UTC

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