Re: Who wants to test cracklinux??

Måns Rullgård
2006-03-28T23:49:52Z

Pavel Machek <pavel@suse.cz> writes:

> Hi!
>
>> I've written a small kernel module & shared object for kernel 2.6 to
>> enable the following for normal users:
>>
>> - inb()/outb()... via a wrapper function
>
> ioperm() does that already, no? You mean, you enable it for non-root,
> too? That's security hole.
>
>> - enable direct IO access (like ioperm())
>> - direct access on physical memory addresses
>
> read/write on /dev/mem. chmod 666 /dev/mem if you want to allow normal
> users to access physical memory (security hole, again).

It's a security risk, but one that you might sometimes take to gain
some performance on a non-critical machine. I've done this in the
past to be able to play videos smoothly on a slow machine.

>> - installation of user space ISR
>
> That seems nice. Does it work with PCI shared interrupts?

I obviously can't comment on this case, but I've successfully done it
previously, so it's demonstrably possible. The code is all available
from vidix.sf.net, although it's not updated to the latest ways of
doing things.

--
Måns Rullgård
mru@inprovide.com