Message-ID: <20150515023221.GC965@madcap2.tricolour.ca>
Date:	Thu, 14 May 2015 22:32:21 -0400
From:	Richard Guy Briggs <rgb@...hat.com>
To:	Paul Moore <pmoore@...hat.com>
Cc:	Steve Grubb <sgrubb@...hat.com>, ebiederm@...ssion.com,
	containers@...ts.linux-foundation.org,
	linux-kernel@...r.kernel.org, linux-audit@...hat.com,
	eparis@...isplace.org, arozansk@...hat.com, serge@...lyn.com,
	zohar@...ux.vnet.ibm.com, viro@...iv.linux.org.uk,
	linux-fsdevel@...r.kernel.org, linux-api@...r.kernel.org,
	netdev@...r.kernel.org
Subject: Re: [PATCH V6 05/10] audit: log creation and deletion of namespace
 instances

On 15/05/14, Paul Moore wrote:
> On Thursday, May 14, 2015 10:57:14 AM Steve Grubb wrote:
> > On Tuesday, May 12, 2015 03:57:59 PM Richard Guy Briggs wrote:
> > > On 15/05/05, Steve Grubb wrote:
> > > > I think there needs to be some more discussion around this. It seems
> > > > like this is not exactly recording things that are useful for audit.
> > > 
> > > It seems to me that either audit has to assemble that information, or
> > > the kernel has to do so.  The kernel doesn't know about containers
> > > (yet?).
> > 
> > Auditing is something that has a lot of requirements imposed on it by
> > security standards. There was no requirement to have an auid until audit
> > came along and said that uid is not good enough to know who is issuing
> > commands because of su or sudo. There was no requirement for sessionid
> > until we had to track each action back to a login so we could see if the
> > login came from the expected place.
> > 
> > What I am saying is we have the same situation. Audit needs to track a
> > container and we need an ID. The information that is being logged is not
> > useful for auditing. Maybe someone wants that info in syslog, but I doubt
> > it. The audit trail's purpose is to allow a security officer to reconstruct
> > the events to determine what happened during some security incident.
> 
> As Eric, and others, have stated, the container concept is a userspace idea, 
> not a kernel idea; the kernel only knows, and cares about, namespaces.  This 
> is unlikely to change.
> 
> However, as Steve points out, there is precedence for the kernel to record 
> userspace tokens for the sake of audit.  Personally I'm not a big fan of this 
> in general, but I do recognize that it does satisfy a legitimate need.  Think 
> of things like auid and the sessionid as necessary evils; audit is already 
> chock full of evilness I doubt one more will doom us all to hell.
> 
> Moving forward, I'd like to see the following:
> 
> * Record the creation/removal/mgmt of the individual namespaces as Richard's 
> patchset currently does.  However, I'd suggest using an explicit namespace 
> value for the init namespace instead of the "unset" value in the V6 patchset 
> (my apologies if you've already changed this Richard, I haven't looked at V7 
> yet).

The "unset" (none) value is only there before the first namespaces have
been created.  After that, any new ones are created relative to the init
namespace of that type.

> * Create a container ID token (unsigned 32-bit integer?), similar to 
> auid/sessionid, that is set by userspace and carried by the kernel to be used 
> in audit records.  I'd like to see some discussion on how we manage this, e.g. 
> how do handle container ID inheritance, how do we handle nested containers 
> (setting the containerid when it is already set), do we care if multiple 
> different containers share the same namespace config, etc.?

(Addressed in another reply.)  Nested will need some careful thought...

> * When userspace sets the container ID, emit a new audit record with the 
> associated namespace tokens and the container ID.

That was the goal of AUDIT_VIRT_CONTROL or AUDIT_NS_INFO messages from
userspace into the kernel.

> * Look at our existing audit records to determine which records should have 
> namespace and container ID tokens added.  We may only want to add the 
> additional fields in the case where the namespace/container ID tokens are not 
> the init namespace.

If we have a record that ties a set of namespace IDs with a container
ID, then I expect we only need to list the containerID along with auid
and sessionID.

> Can we all live with this?  If not, please suggest some alternate ideas; 
> simply shouting "IT'S ALL CRAP!" isn't helpful for anyone ... it may be true, 
> but it doesn't help us solve the problem ;)

Thanks Paul.

> paul moore

- RGB

--
Richard Guy Briggs <rbriggs@...hat.com>
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
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