Re: FW: XP as a base for NetTop

[Luke Kenneth Casson Leighton <lkcl@lkcl.net>]

On Wed, May 26, 2004 at 04:49:00PM -0700, Chris Babcock wrote:
> > Stephen Smalley wrote:
> >> Looks like Microsoft is indeed pushing an XP-based NetTop
> >> called Trusted Multi-Net/Typhon XP, e.g.:
> >>
> >> http://www.computerweekly.com/Article123730.htm
> >>
> > http://download.microsoft.com/download/4/f/8/4f89f896-f020-46d1-adc0-08a18c8432d
> > 5/Trusted%20Multi-Net%20for%20SSE%202003.ppt
> >
> 
> Interesting.
> 
> The slides indicate that in their system threads are able to change what
> context they run in.
> 
> It makes me wonder if they have some magic to prevent threads from
> poluting shared data (unlikely), or if it is just a hack to avoid process
> vs. thread design issues on windows.

NT's security model uses DCE/RPC applications to compartmentalise
pretty much everything.

the creation of new processes therefore takes a stunningly long time
(relatively speaking) due to having to go in and out of another
application in order to vet the user's access rights.

the advantage is that process creation can in theory be vetted
and controlled by a remote and centralised NT "primary domain
controller", with the obvious implications:

1) you always have to have a connection to \\yourpdc\PIPE\NETLOGON

2) process creation could be severely delayed if that connection is
   disrupted.

consequently, to avoid any significant delays, threading is highly
recommended in NT "services".

i presume that it is possible to cache security contexts and then
make a rapid switch to them?

makes me wonder why they didn't do the same sort of thing for processes.

oh well.

l.


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