On 2018-02-13, Enrico Weigelt <lkml-EcKl7qYKIbxeoWH0uzbU5w@public.gmane.org> wrote:
> On 13.02.2018 22:12, Enrico Weigelt wrote:
> > I'm currently trying to implement plan9 semantics on Linux and
> > yet sorting out how to do the mount namespace handling.
> > 
> > On plan9, any unprivileged process can create its own namespace
> > and mount/bind at will, while on Linux this requires CAP_SYS_ADMIN.
> > 
> > What is the reason for not allowing arbitrary users to create their
> > own private mount namespace ? What could go wrong here ?

You can do this by creating a new user namespace (CLONE_NEWUSER), which
then gives you the required permissions to create other namespaces
(CLONE_NEWNS). This is how "rootless containers" or unprivileged
containers operate.

-- 
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>