Subject: Re: Boot netbsd on playstation2 with modchip
To: None <port-playstation2@NetBSD.org>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: port-playstation2
Date: 12/17/2006 22:23:41
>> I'd certainly appreciate any work done on lifting [the dependence on
>> the Sony Linux kit]. I'd be very interested in booting NetBSD on
>> mine via some variant of the Independence Day exploit [...]
> How does the ID exploit work?
Note that the following is second-hand knowledge, except where I
specifically mention my own case. While my machine behaves more or
less as though it were accurate, I have not dug deep enough to verify
the details myself.
It's a classic smash-the-stack buffer overflow. When booting a PS1
game, it takes the game's ID (eg, SCUS 63524 - an invented but
plausible-looking example - these are usually present on the game's
jewel case packaging) and looks on any PS2 memory cards in place,
looking for a file with a fixed name I forget. If it find the file, it
reads thorugh it, looking for a line giving the game's ID. If found,
the rest of the line is treated as various options - this is presumably
intended to allow specifying quirks for cases where the default PS1
emulation is not quite good enough for the game, though I don't know of
any examples.
But the line, if found, is copied into a fixed-size buffer on the
stack, which turns out to always be at the same address. Trivial to
exploit. The only hard part is getting a suitable file onto your
memory card in the first place. Someone who already has it installed
can write it for you (that's how I got started); there's a commercial
product called HDloader which also suffices, if you have Linux on your
house LAN and a disk (not necessarily the Sony one) in your PS2 - the
disk might not actually be necessary. I conjecture the Linux kit also
works; I would expect a PS2 dev station to work as well, but I
understand Sony is downright paranoid about their getting into
unconsecrated hands.
> Of course, the one nice thing you do get with the Linux kit is the
> VGA adapter.. although I suppose this isn't as big of a deal these
> days with HDTVs becoming cheaper and cheaper.
I don't expect to buy an HDTV because (almost?) all of them here would
come from the States and thus contain DRM crippling. But a friend of
mine (the one who first got me into console gaming, by giving me a
PSone) gave me a scan doubler which turns a TV signal into something a
typical VGA monitor can handle.
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