[Gllug] Anyone having broadband (probably PlusNet) problems today?

[Nix]

On Tue, 29 Mar 2005, Russell Howe whispered secretively:
> On Tue, Mar 29, 2005 at 10:35:13AM +0100, Nix wrote:
>> Actaully, in general, if the hardware is DMA-capable, the firmware could
>> do anything in RAM it liked, including (if the firmware were malicious
>> or buggy) introducing security holes.
>> 
>> Disk controllers tend to be DMA-capable. :)
> 
> True, and I suppose this would bypass the memory protections afforded by
> the CPU and/or MMU as I guess the DMA transfer would bypass this?

Yeah, DMA is direct-to-physical-memory: you lose.

(This is why scatter-gather support is so important: contiguous virtual
memory blocks tend to be discontiguous in physical memory...)

-- 
This is like system("/usr/funky/bin/perl -e 'exec sleep 1'");
   --- Peter da Silva
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