[PATCH V6 05/10] audit: log creation and deletion of namespace instances
Richard Guy Briggs
rgb at redhat.com
Fri May 15 02:25:27 UTC 2015
On 15/05/14, Eric W. Biederman wrote:
> Paul Moore <pmoore at redhat.com> writes:
> > 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:
> > * 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.?
> > 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 ;)
> Without stopping and defining what someone means by container I think it
> is pretty much nonsense.
Not complete, but this is why I'm asking for a standards document...
> Should every vsftp connection get a container every? Every chrome tab?
> At some of the connections per second numbers I have seen we might
> exhaust a 32bit number in an hour or two. Will any of that make sense
> to someone reading the audit logs?
So making it 64bits buys us some time, but sure... I think your
definition of a container may be a bit more liberal than what we're
trying to understand...
> Without considerning that container creation is an unprivileged
> operation I think it is pretty much nonsense. Do I get to say I am any
> container I want? That would seem to invalidate the concept of
> userspace setting a container id.
Ok, my impression was that we're dealing with a privileged application
as I alluded with the need to create a new CAP_AUDIT_CONTAINER_ID or
> How does any of this interact with setns? AKA entering a container?
You mean entering another namespace that might all be part of one
container? Or an an application attempting to enter the namespace of
> I will go as far as looking at patches. If someone comes up with
> a mission statement about what they are actually trying to achieve and a
> mechanism that actually achieves that, and that allows for containers to
> nest we can talk about doing something like that.
I don't pretend these patches are anywhere near finished or ready for
> But for right now I just hear proposals for things that make no sense
> and can not possibly work. Not least because it will require modifying
> every program that creates a container and who knows how many of them
> there are. Especially since you don't need to be root. Modifying
> /usr/bin/unshare seems a little far out to me.
My understanding is that just spawning or changing namespace doesn't
imply spawning or changing containers. I also don't necessarily assume
that creating a container is an atomic operation, though that concept
might make some sense to understand or predict the boundaries of
Richard Guy Briggs <rbriggs at redhat.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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