Date: Fri, 23 Jul 2004 09:48:09 -0700 From: Brooks Davis <brooks@one-eyed-alien.net> To: Maxim Sobolev <sobomax@portaone.com> Cc: Andrew Gallatin <gallatin@cs.duke.edu> Subject: Re: Excellent job on the firewire support! Message-ID: <20040723164809.GA12747@Odin.AC.HMC.Edu> In-Reply-To: <41012639.3020102@portaone.com> References: <16634.47272.768935.436137@grasshopper.cs.duke.edu> <200407182039.10773.dfr@nlsystems.com> <16634.54674.966908.540880@grasshopper.cs.duke.edu> <200407182104.53221.dfr@nlsystems.com> <16638.32914.509773.486468@grasshopper.cs.duke.edu> <1090421941.7114.26.camel@builder02.qubesoft.com> <41012639.3020102@portaone.com>
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[-- Attachment #1 --] On Fri, Jul 23, 2004 at 05:52:41PM +0300, 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. In high security environments, they use a tube of epoxy. ;-) -- Brooks -- Any statement of the form "X is the one, true Y" is FALSE. PGP fingerprint 655D 519C 26A7 82E7 2529 9BF0 5D8E 8BE9 F238 1AD4 [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQFBAUFIXY6L6fI4GtQRAqLWAKC3q1TBDGvA7NMUWgb+q8oTvvtU1gCgy48/ Od+By7myC2GXEvE4ATAIU8w= =8lcY -----END PGP SIGNATURE-----
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