[Gllug] Editors

[home at alexhudson.com]

On Sun, Jul 29, 2001 at 06:26:14PM +0100, David Freeman wrote:
> > swapoff [part]
> > 
> > Not recommended though. 
> 
> Why is it not recommended?

Because when you have swap, and you start getting tight on memory, the
computer grinds and goes real slow. If you don't have swap, the first
indication of an app running out of the bounds of memory is that it gets
OOM'd. Ie., disappears. Eg, "Hey! Where did X just go????". Linux
overcommits memory, and the vm is tuned for swap access. You _can_ do
without swap, but, it's not recommended :)

> > Not for applications AFAIK - but it is certainly possible for an
> > application to state that pages should be locked in RAM.
> 
> Can you say that again slowly?

Hmm, worded confusingly :) I don't know of any way to tell the OS to lock an
app in RAM, but it is possible for an app to allocate a memory space which
is locked in RAM. So - a specially written app could have the behaviour you
require; I just don't know of a way to do it to any app you want.

Does that make more sense ?? :)

> > Security is always a compromise. 
> 
> It might be, but more to the point is, should it be?

It has to be. Once you get beyond a certain point, the more secure a machine
is, the more difficult it is to use. It comes to a point where your use of
the computer becomes less and less efficient, and I think you have to
justify that.

> I do understand both stegFS and RIP. I can agree with you on some of
> the above. They ask for my pass phrase which I give them, they can then
> unlock layer 1, but I can plausibly deny the existance of layers 2 - 8
> etc...

I would bet against you being able to plausibly deny their existence :) 

Let's say that you've set it up half-decently - no .historys, you've made
sure stuff isn't going into swap, etc. What about application logs? You've
got to turn those off, because otherwise you've logged the fact that you've
edited files which don't exist (by the path they would also know what steg
level it was in). Gotta get rid of those pesky core dumps too, although
hopefully they wouldn't happen too often (nice way a spook could get a
memory snapshot from your system, though, if they had you monitored - which
they would before requested keys under RIP - and were able to crash your
machine remotely). Have to make sure syslog isn't doing anything dodgy
either. And we have to make sure that the stegfs stuff is shut down before
any cron jobs run - they might start grepping our directories for cores,
etc., and leave traces in their logs. 

And that's just system stuff - we haven't even begun to delve into other
areas - such as filesystem ("we notice the pattern of activity on this
filesystem points to the fact you have a number of hidden files you haven't
told us about"). Plus, the fact that you are able to plausibly deny
(supposedly) the existence of files to authorities means that you are also
able to plausibly deny their existence to the OS (i.e., it will trash
files), so you're probably going to want to make backups too (this is
sensitive data, right?), and take some kind of security precaution with
those too...... back to square one...

Cheers,

Alex.

-- 
Gllug mailing list  -  Gllug at linux.co.uk
http://list.ftech.net/mailman/listinfo/gllug