Re: Filesystem Capabilities in 2.6?

On Sun, Nov 03, 2002 at 11:56:22AM -0500, Alexander Viro wrote:
> 
> 
> On 3 Nov 2002, Alan Cox wrote:
> 
> > On Sun, 2002-11-03 at 14:51, Alexander Viro wrote:
> > > No messing with chroot needed - just a way to irrevertibly turn off the
> > > ability (for anybody) to do mounts/umounts in a given namespace and ability
> > > to clone that namespace.  Then give them ramfs for root and bind whatever
> > > you need in there.  No breaking out of that, since there is nothing below
> > > their root where they could break out to...
> > 
> > mkdir foo
> > chroot foo
> > cd ../../../..
> > chroot .
> 
> ... will give him nothing, since he is not in chroot jail to start with.
> He has a namespace of his own with his own root filesystem.  Which has
> several empty directories and nothing else - everything else is bound on
> these.  He is at his absolute root and can't break out of it - there is
> nowhere to break out.  So his /foo will be a subdirectory of root of his
> root filesystem.  OK, he chroots there.  His cwd is still at absolute root
> and he can follow .. until he's blue in the face - he will stay where he
> started.

Plan 9 !

-- 
---------------------------------------------------------
Victor Yodaiken 
Finite State Machine Labs: The RTLinux Company.
www.fsmlabs.com  www.rtlinux.com
1+ 505 838 9109