Re: Building a BSD-jail clone out of namespaces

From: Chris Webb
Date: Thu Jun 06 2013 - 12:47:00 EST


"Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> 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.
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