Subject: Re: Regarding XFree
To: Rakhesh Sasidharan <rakhesh@cse.iitd.ernet.in>
From: Richard Rauch <rauch@eecs.ukans.edu>
List: netbsd-help
Date: 02/26/2001 06:55:47
> Hi,

Greetings from Kansas.  I'm glad that you sorted out the problem, more or
less.


> I finally figured out what was wrong, and why I couldn't run X on my
> machine.  Here's what:
 [...]
> (--) checkDevMem: warning: failed to open /dev/mem and /dev/xf86
>         (No such file or directory)
>         linear framebuffer access unavailable
 [...]
> Generally I only get the last line (marked with a <<).  This struck me as
> possibly being a problem with securelevel (I was using securelevel 1), and
> so lowered that and re-tried.  And this time it clicked!
> 
> Is this normal ?  I mean, if I want to use securelevel 1 atleast, then I
> won't be able to use X ?

That's approximately true.  As I understand it (which admittedly is only
imperfectly), the problem emerges because XFree86 is relying on something
that is inherently a security hole.  If you want a secure system, you want
the holes plugged.

I run with kernel option ``options INSECURE'' on my main system, since I
use X all of the time.

There is a compromise.  In pkgsrc, look at sysutils/aperture.  I don't run
aperture, and am not familiar with it, so I'll abstain from further
comment on it, and let you look at it for yourself (or get information
from people who DO know more about it).

A final option may be to either use the SVGA X server with your current
card, or swap in an older video card.  The aperture pkg/DESCR file
suggests that older cards would work with XFree86 without X needing direct
memory access.  This may result in suboptimal performance (or appearance),
but if it works you could avoid compromising at all on security.


  "I probably don't know what I'm talking about." --rauch@eecs.ukans.edu