lkml.org 
[lkml]   [1999]   [Mar]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: 3dfx - a security hazard?
Nathan Hand wrote:
>
> On Thu, 11 Mar 1999, Tigran Aivazian wrote:
>
> > > It didnt - its a security hazard. Any user with access to it can crash
> > > the entire machine
> >
> > I am probably missing something, but access to both /dev/3dfx and (e.g.)
> > /dev/mem is controlled by filesystem permission rules. Writing garbage to
> > either will crash the entire machine. Why is one a security hazard and
> > another is not?
>
> The 3dfx can lock the pci bus if fed garbage. The /dev/3dfx driver
> doesn't stop garbage being fed in, and so has no benefit over suid
> glide libs which tickle the hardware directly.

The only real secure way of handling such devices are with full kernel
drivers or at least kernel drivers that do proper sanity checking.
However, since 3Dfx won't release anything but the binary-only Glide
libs, we've got only the two choices. Both ways of using Glide
introduce security risks. Suid-root however has a larger set of
security risks that are more easily exploitable.

We've been through this argument before with the X/fbcon/svgalib/KGI
deal. Control of graphics hardware, like all other hardware, is the
domain of the kernel. Needing root privileges to access hardware is a
bad situation no matter how you look at it.

> The proper way is to have an opengl interface which prevents nasty
> garbage being sent to the 3dfx card. This has numerous other neato
> benefits too, like hardware independence for 3d developers, and an
> already well documented API that ties in nicely with X11 if you're
> looking for that sort of thing.

OpenGL is truly the way to go, but the X server shouldn't have to get
involved. It just adds more overhead to a usually speed demanding
operation. OpenGL vs. Glide hasn't been much of an issue up until now
since 3Dfx was the only hardware that had _any_ support under Linux.
Now that the Matrox G200 specs are out there will finally be more
supported cards and OpenGL will gain acceptance. However, until 3Dfx
releases info, you still need Glide, even to use Mesa, which means
user-space access to the hardware.

--

Brian Gerst

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:50    [W:0.897 / U:0.016 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site