Re: [Part1 PATCH 00/22] Add namespace support for audit

["Serge E. Hallyn" <serge@hallyn.com>]

Quoting Eric Paris (eparis@redhat.com):
> On Thu, 2013-06-20 at 11:02 +0800, Gao feng wrote:
> > On 06/20/2013 04:51 AM, Eric Paris wrote:
> > > On Wed, 2013-06-19 at 16:49 -0400, Aristeu Rozanski wrote:
> > >> On Wed, Jun 19, 2013 at 09:53:32AM +0800, Gao feng wrote:
> > >>> This patchset is first part of namespace support for audit.
> > >>> in this patchset, the mainly resources of audit system have
> > >>> been isolated. the audit filter, rules havn't been isolated
> > >>> now. It will be implemented in Part2. We finished the isolation
> > >>> of user audit message in this patchset.
> > >>>
> > >>> I choose to assign audit to the user namespace.
> > >>> Right now,there are six kinds of namespaces, such as
> > >>> net, mount, ipc, pid, uts and user. the first five
> > >>> namespaces have special usage. the audit isn't suitable to
> > >>> belong to these five namespaces, And since the flag of system
> > >>> call clone is in short supply, we can't provide a new flag such
> > >>> as CLONE_NEWAUDIT to enable audit namespace separately. so the
> > >>> user namespace may be the best choice.
> > >>
> > >> I thought it was said on the last submission that to tie userns and
> > >> audit namespace would be a bad idea?
> > > 
> > > I consider it a non-starter.  unpriv users are allowed to launch their
> > > own user namespace.  The whole point of audit is to have only a priv
> > > user be allowed to make changes.  If you tied audit namespace to user
> > > namespace you grant an unpriv user the ability to modify audit.
> > > 
> > 
> > I understand your views.
> > 
> > But ven the unpriv user are allowed to make changes, they can do no harm.
> > they can only make changes on the audit namespace they created.they can
> > only communicate with the audit namespace they created.
> 
> Imagine I set up my machine to audit all user access to super secret
> information.  With your patch set all an malicious user has to do is
> create a new user namespace.  Now when he accesses the super secret
> information it will be logged inside the user namespace he created.  So
> he can just dump those logs in the trash.

Right, I thought I'd pointed this out last time - it makes LSPP
certification impossible.

> I believe that each audit namespace should require priv
> (CAP_AUDIT_CONTROL) in the user namespace that created the current audit
> namespace.  So lets say the machine boots and we are in the init_user

The problem with this is that ...  people will then hand out
CAP_AUDIT_CONTROL :)

I'd be happier with Eric Biederman's suggestion:  You can create a new
audit namespace, but all of the initial audit namespace's filters still
(separately) apply to you.

-serge