[linux-elitists] Introducing Myself

Jason Spence jspence@lightconsulting.com
Wed Jan 7 09:55:57 PST 2004


On Wed, Jan 07, 2004 at 06:29:34PM +0100, Eugen Leitl wrote: 
> On Wed, Jan 07, 2004 at 09:17:36AM -0800, Ben Woodard wrote:
> > This might be a stupid question but does anybody know if BASIC is still
> > hiding there in our BIOS. I don't remember how to get into it and
> > haven't stumbled across it in a while but I sort of thought it was there
> > somewhere. I think I had an XT which had it for sure and there was some
> > trick to get into it but I've forgotten what that trick is otherwise I'd
> > try it on a spare machine that I have here.

That was an artifact of the days when you either were a hobbyist or an
IBM type, the hobbyists used an awful lot of BASIC, and so the vendors
of hobbyist type machines felt providing one in ROM would be a
competitive feature.

These days the hobbysts are just as good or better than the
professional programmers and so we all kind of look funny at BASIC
since there's perfectly good alternative languages to be religious
about like Perl, Python, etc.  As a result, every BIOS I've seen in
the last, say, 14 years or so hasn't had a BASIC in ROM.

> Have you considered http://www.openbios.info/ or http://www.linuxbios.org/ ?

Also http://sourceforge.net/projects/cobalt-rom;  Somehow the Cobalt
Raq BIOS got open sourced.

Note that doing so opens up the password hashing algorithm and CMOS
checksum algorithm, allowing people with root to ENABLE AND CHANGE
YOUR FIRMWARE PASSWORDS with nothing more than an iopl() and some port
0x70 and 0x71 twiddling.

I used that in a few hacking contests; it's really quite entertaining
to see your competition locked out of their own VMware machine [1] :)

[1] Although the BX chipset and Phoenix BIOS combination emulated by
VMware doesn't keep the password in the lower 128 bytes; there's an
extended 128 bytes accessible using the usual protocol at ports 0x72
and 0x73 where the password checksum is stored.

-- 
 - Jason           Last known location:  1.3 miles northeast of Union City, CA

Always borrow money from a pessimist; he doesn't expect to be paid
back.



More information about the linux-elitists mailing list