Re: [9fans] security questions

["Devon H. O'Dell" <devon.odell@gmail.com>]

2009/4/17 erik quanstrom <quanstro@quanstro.net>:
>> What if each user can have a separate IP stack, separate
>> (virtualized) interfaces and so on?
>
> already possible, but you do need 1 physical ethernet
> per ip stack if you want to talk to the outside world.

I'm sure it wouldn't be hard to add a virtual ``physical'' interface,
even though that seems a little bit pervasive, given the already
semi-virtual nature due to namespaces. Not sure how much of a hassle
it would be to make multiple stacks bindable to a single interface...
but perhaps that's the better way to go?

>> But you'd have to implement some sort of limits on
>> oversubcribing (ratio of virtual to real resources). Unlike
>> securitization in the hedge fund world.
>
> this would add a lot of code and result in the same problem
> as today — you can be run out of a criticial resource.

Oversubscribing is the root of the problem. In fact, even if it was
already done, on a terminal server, imagmem is also set to kpages. So
if someone found a way to blow up the kernel's draw buffer, boom. I
don't know how far reaching that is, as I've never really seen the
draw code.

Unfortunately, that's what you have to do unless you can afford to
invest in more hardware, or have a small userbase. Or find some middle
ground -- and maybe that's what the `virtualization' would address.

> - erik

--dho