Re: [PATCH] private mounts

[Jamie Lokier <jamie@shareable.org>]

Ram wrote:
> > Much better is the proposal to make namespaces first-class objects,
> > that can be switched to.  Then users can choose to have themselves a
> > namespace containing their private mounts, if they want it, with
> > login/libpam or even a program run from .profile switching into it.
> > 
> > While users can be allowed to create their own namespaces which affect
> > the path traversal of their _own_ directories, it's important that the
> > existence of such namespaces cannot affect path traversal of other
> > directories such as /etc, or /autofs/whatever - and that creation of
> > namespaces by a user cannot prevent the unmounting of a non-user
> > filesystem either.
> > 
> > The way to do that is shared subtrees, or something along those lines.
> 
> Right. Adding to it. To begin with the system namespace has all its
> entire tree shared. So when a new namespace is cloned, the new namespace
> can see any new mount/unmount/binds done in the system namespace as
> well. (System namespace is the first initial namespace created by
> default).
> 
> Any private mounts done by the user in his private-namespace 
> will first make that part of the tree private first and then will
> continue with the mount. Otherwise the private mount will end up showing
> in the system namespace(since it is shared).

Yes, exactly that.

-- Jamie