Re: Building a BSD-jail clone out of namespaces

[Chris Webb <chris@arachsys.com>]

"Eric W. Biederman" <ebiederm@xmission.com> writes:

> That will work, but you really don't want to run with uid == 0 mapped to
> uid == 0.  There are too many things in /proc and /sys and similar that
> grant access to uid == 0.

Many thanks for the swift reply. If I map UID zero in the userns to a
non-zero UID outside (say -1), is there any way to use the userns UIDs
instead of host UIDs when accessing the container's root filesystem so I
don't end up with strange file ownerships on disk? This would prevent me
from using the same filesystem on physical hosts or in VMs.

I don't think there's any kernel mechanism that lets me apply a UID
translation layer as part of a bind mount is there?

Cheers,

Chris.