Re: User Access to I/O ports

Pavel Machek (pavel@Elf.mj.gts.cz)
Tue, 3 Jun 1997 20:16:02 +0200

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> Dear kernel maintainers,
>
> The following is actually nearly from word to word the e-mail from
> Gerry Swislow to Linus Torvalds in 1994, only the idea wasn't accomplished
> into a patch then. The needed change is actually quite important, so probably
> someone is willing to implement it in future kernel versions.
>
> I would like to suggest a change that would make the Linux
> version of the KDADDIO/KDDELIO and KDENABIO/KDDISABIO ioctl() calls
> work the same as the AT&T/USL System V/386 Releases 3 and SVR4.x
> implementations.

There's nothing special about video ports. You do _NOT_ need to change
kernel. Make suid root program that asks kernel for i/o ports, then
looses its privileges and exec's your customer's program.

And you are done.

[Or is something I miss? If so, contact me personaly, this does not
quite belong to this list.]

Pavel

--
I'm really pavel@atrey.karlin.mff.cuni.cz. 	   Pavel
Look at http://atrey.karlin.mff.cuni.cz/~pavel ;-).

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