From: Sam Vilain (sam_at_vilain.net)
Date: Fri 09 May 2003 - 14:58:15 BST
On Fri, 09 May 2003 08:50, you wrote:
> Am just thinking in terms of UML running it's own kernel in userspace,
> vs a system running in a chrooted environment. Which would be easier to
> break out of?
Unless you patch the host kernel (with ``skas-mode''), UML's pretty
insecure. Without kernel co-operation, it has no way of enforcing memory
management between processes running inside the client OS. While you
can't break out to the host OS, you don't have much security within the
system.
If you're just allocating one UML instance to one user, this is fine of
course.
In my opinion, Vserver is trying to complete the UNIX virtualisation that
the classic chroot() call suggested. So, it builds on a refined model of
UNIX user and process seperation.
However, there are still bugs in the capabilities system and for instance
some drivers will let you control them in situations where they shouldn't
(because there is no CAP_SYS_ADMIN). This applies to files in /proc and
ioctl()'s.
-- Sam Vilain, sam_at_vilain.netWhat usually happens in the educational process is that the faculties are dulled, overloaded, stuffed and paralyzed so that by the time most people are mature they have lost their innate capabilities. -- Richard Buckminster Fuller