[patch 0/8] unprivileged mount syscall

[Ian Kent]

On Wed, 2007-04-11 at 12:48 +0200, Miklos Szeredi wrote:
> > > >>
> > > >> - users can use bind mounts without having to pre-configure them in
> > > >>   /etc/fstab
> > > >>
> > > 
> > > This is by far the biggest concern I see.  I think the security 
> > > implication of allowing anyone to do bind mounts are poorly understood.
> > 
> > And especially so since there is no way for a filesystem module to veto
> > such requests.
> 
> The filesystem can't veto initial mounts based on destination either.
> I don't think it's up to the filesystem to police bind/move mounts in
> any way.

But if a filesystem can't or the developer thinks that it shouldn't for
some reason, support bind/move mounts then there should be a way for the
filesystem to tell the kernel that.

Surely a filesystem is in a good position to be able to decide if a
mount request "for it" should be allowed to continue based on it's "own
situation and capabilities".

Ian