[sldev] Improving the avatar in SL: hair...

[Callum Lerwick]

On Mon, 2007-08-27 at 07:55 +0000, Matthew Dowd wrote:
> > In theory you could just allow people to write shaders in GLSL. I'm not
> > up on the spec but seems to me that should be safe, the worst people
> > could do is maybe lock up the video card, and I would hope that would
> > only be because of bugs in the GL driver's compiler.
> 
> You are basically writing machine code to run on the GPU - there's limited checking even a perfect/bug free driver could do.

Well, you're not. You're programming in GLSL, a fairly limited language,
for a fairly limited architecture. You don't get things such as pointers
to cause trouble with, for example. The worst you could do is maybe
infinite loops, which could be dealt with.

Though I'm sure someone will figure out something.

An unprivileged user space program with the ability to lock up the
hardware is a major security failure any way you slice it. It should not
be possible. If it is, oh boy, the vulnerable video cards are going to
find themselves blacklisted by systems administrators worldwide until
they fix it. :)
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