[RFC Part1 PATCH 00/20 v2] Add namespace support for audit

[Serge E. Hallyn]

Quoting Gao feng (gaofeng at cn.fujitsu.com):
> Here is the v1 patchset: http://lwn.net/Articles/549546/
> 
> The main target of this patchset is allowing user in audit
> namespace to generate the USER_MSG type of audit message,
> some userspace tools need to generate audit message, or
> these tools will broken.
> 
> And the login process in container may want to setup
> /proc/<pid>/loginuid, right now this value is unalterable
> once it being set. this will also broke the login problem
> in container. After this patchset, we can reset this loginuid
> to zero if task is running in a new audit namespace.
> 
> Same with v1 patchset, in this patchset, only the privileged
> user in init_audit_ns and init_user_ns has rights to
> add/del audit rules. and these rules are gloabl. all
> audit namespace will comply with the rules.
> 
> Compared with v1, v2 patch has some big changes.
> 1, the audit namespace is not assigned to user namespace.
>    since there is no available bit of flags for clone, we
>    create audit namespace through netlink, patch[18/20]
>    introduces a new audit netlink type AUDIT_CREATE_NS.
>    the privileged user in userns has rights to create a
>    audit namespace, it means the unprivileged user can
>    create auditns through create userns first. In order
>    to prevent them from doing harm to host, the default
>    audit_backlog_limit of un-init-audit-ns is zero(means
>    audit is unavailable in audit namespace). and it can't
>    be changed in auditns through netlink.

So the unprivileged user can create an audit-ns, but can't
then actually send any messages there?  I guess setting it
to something small would just be hacky?