Re: [RFC][PATCH 8/8] SLIM: documentation

[Pavel Machek <pavel@ucw.cz>]

Hi!

> > > +In normal operation, the system seems to stabilize with a roughly
> > > +equal mixture of SYSTEM, USER, and UNTRUSTED processes. Most
> >
> > So you split processes to three classes (why three?), and
> > automagically move them between classes based on some rules? (What
> > rules?)
> >
> > Like if I'm UNTRUSTED process, I may not read ~/.ssh/private_key? So
> > files get this kind of labels, too? And it is "mozilla starts as a
> > USER, but when it accesses first web page it becomes UNTRUSTED"?
> 
> Processes are not moved from one integrity level to another, but are
> demoted when they read from a lower integrity level object. By
> definition sockets, are defined as UNTRUSTED, so reading from a
> socket demotes the process to UNTRUSTED.  (Secrecy is a separate
> attribute.) In the Mozilla example, /usr/bin/mozilla is defined as
> SYSTEM, preventing any process with lesser integrity from modifying
> it.  'level -s' displays the level of the current process or of a
> given file.  For example,
> 
> [zohar@L3X098X ~]$ level -s /usr/bin/mozilla
> /usr/bin/mozilla
>         security.slim.level: SYSTEM PUBLIC
> 
> Both mozilla and firefox-bin are defined as SYSTEM, as soon as the
> firefox-bin process opens a socket, the process is demoted to
> UNTRUSTED.
> 
> I hope this answered some of your questions.  We're working on
> more comprehensive documentation, which we'll post with the next
> release.

Do you have examples where this security model stops an attack?

Both my mail client and my mozilla will be UNTRUSTED (because of
network connections, right?) -- so mozilla exploit will still be able
t osee my mail? Not good. And ssh connects to the net, too, so it will
not even protect my ~/.ssh/private_key ?
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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