From: Richard Guy Briggs <rgb@redhat.com>
To: Paul Moore <paul@paul-moore.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>,
Tycho Andersen <tycho@tycho.ws>,
containers@lists.linux-foundation.org, linux-api@vger.kernel.org,
Linux-Audit Mailing List <linux-audit@redhat.com>,
linux-fsdevel@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
netdev@vger.kernel.org, netfilter-devel@vger.kernel.org,
sgrubb@redhat.com, omosnace@redhat.com, dhowells@redhat.com,
simo@redhat.com, Eric Paris <eparis@parisplace.org>,
ebiederm@xmission.com, nhorman@tuxdriver.com
Subject: Re: [PATCH ghak90 V6 02/10] audit: add container id
Date: Mon, 8 Jul 2019 14:05:58 -0400 [thread overview]
Message-ID: <20190708180558.5bar6ripag3sdadl@madcap2.tricolour.ca> (raw)
In-Reply-To: <CAHC9VhThLiQzGYRUWmSuVfOC6QCDmA75BDB7Eg7V8HX4x7ymQg@mail.gmail.com>
On 2019-05-30 15:29, Paul Moore wrote:
> On Thu, May 30, 2019 at 1:09 PM Serge E. Hallyn <serge@hallyn.com> wrote:
> > On Wed, May 29, 2019 at 06:39:48PM -0400, Paul Moore wrote:
> > > On Wed, May 29, 2019 at 6:28 PM Tycho Andersen <tycho@tycho.ws> wrote:
> > > > On Wed, May 29, 2019 at 12:03:58PM -0400, Paul Moore wrote:
> > > > > On Wed, May 29, 2019 at 11:34 AM Tycho Andersen <tycho@tycho.ws> wrote:
> > > > > > On Wed, May 29, 2019 at 11:29:05AM -0400, Paul Moore wrote:
> > > > > > > On Wed, May 29, 2019 at 10:57 AM Tycho Andersen <tycho@tycho.ws> wrote:
> > > > > > > > On Mon, Apr 08, 2019 at 11:39:09PM -0400, Richard Guy Briggs wrote:
>
> ...
>
> > > > > > > The current thinking
> > > > > > > is that you would only change the audit container ID from one
> > > > > > > set/inherited value to another if you were nesting containers, in
> > > > > > > which case the nested container orchestrator would need to be granted
> > > > > > > CAP_AUDIT_CONTROL (which everyone to date seems to agree is a workable
> > > > > > > compromise).
> > > >
> > > > won't work in user namespaced containers, because they will never be
> > > > capable(CAP_AUDIT_CONTROL); so I don't think this will work for
> > > > nesting as is. But maybe nobody cares :)
> > >
> > > That's fun :)
> > >
> > > To be honest, I've never been a big fan of supporting nested
> > > containers from an audit perspective, so I'm not really too upset
> > > about this. The k8s/cri-o folks seem okay with this, or at least I
> > > haven't heard any objections; lxc folks, what do you have to say?
> >
> > I actually thought the answer to this (when last I looked, "some time" ago)
> > was that userspace should track an audit message saying "task X in
> > container Y is changing its auditid to Z", and then decide to also track Z.
> > This should be doable, but a lot of extra work in userspace.
> >
> > Per-userns containerids would also work. So task X1 is in containerid
> > 1 on the host and creates a new task Y in new userns; it continues to
> > be reported in init_user_ns as containerid 1 forever; but in its own
> > userns it can request to be known as some other containerid. Audit
> > socks would be per-userns, allowing root in a container to watch for
> > audit events in its own (and descendent) namespaces.
> >
> > But again I'm sure we've gone over all this in the last few years.
> >
> > I suppose we can look at this as a "first step", and talk about
> > making it user-ns-nestable later. But agreed it's not useful in a
> > lot of situations as is.
>
> [REMINDER: It is an "*audit* container ID" and not a general
> "container ID" ;) Smiley aside, I'm not kidding about that part.]
>
> I'm not interested in supporting/merging something that isn't useful;
> if this doesn't work for your use case then we need to figure out what
> would work. It sounds like nested containers are much more common in
> the lxc world, can you elaborate a bit more on this?
>
> As far as the possible solutions you mention above, I'm not sure I
> like the per-userns audit container IDs, I'd much rather just emit the
> necessary tracking information via the audit record stream and let the
> log analysis tools figure it out. However, the bigger question is how
> to limit (re)setting the audit container ID when you are in a non-init
> userns. For reasons already mentioned, using capable() is a non
> starter for everything but the initial userns, and using ns_capable()
> is equally poor as it essentially allows any userns the ability to
> munge it's audit container ID (obviously not good). It appears we
> need a different method for controlling access to the audit container
> ID.
We're not quite ready yet for multiple audit daemons and possibly not
yet for audit namespaces, but this is starting to look a lot like the
latter.
If we can't trust ns_capable() then why are we passing on
CAP_AUDIT_CONTROL? It is being passed down and not stripped purposely
by the orchestrator/engine. If ns_capable() isn't inherited how is it
gained otherwise? Can it be inserted by cotainer image? I think the
answer is "no". Either we trust ns_capable() or we have audit
namespaces (recommend based on user namespace) (or both).
At this point I would say we are at an impasse unless we trust
ns_capable() or we implement audit namespaces.
I don't think another mechanism to trust nested orchestrators/engines
will buy us anything.
Am I missing something?
> Punting this to a LSM hook is an obvious thing to do, and something we
> might want to do anyway, but currently audit doesn't rely on the LSM
> for proper/safe operation and I'm not sure I want to change that now.
>
> The next obvious thing is to create some sort of access control knob
> in audit itself. Perhaps an auditctl operation that would allow the
> administrator to specify which containers, via their corresponding
> audit container IDs, are allowed to change their audit container ID?
> The permission granting would need to be done in the init userns, but
> it would allow containers with a non-init userns the ability to change
> their audit container ID. We would probably still want a
> ns_capable(CAP_AUDIT_CONTROL) restriction in this case.
This auditctl knob of which you speak is an additional API, not changing
the existing proposed one.
> Does anyone else have any other ideas?
>
> --
> paul moore
> www.paul-moore.com
- RGB
--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635
next prev parent reply other threads:[~2019-07-08 18:06 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-09 3:39 [PATCH ghak90 V6 00/10] audit: implement container identifier Richard Guy Briggs
2019-04-09 3:39 ` [PATCH ghak90 V6 01/10] audit: collect audit task parameters Richard Guy Briggs
2019-04-09 3:39 ` [PATCH ghak90 V6 02/10] audit: add container id Richard Guy Briggs
2019-05-29 14:57 ` Tycho Andersen
2019-05-29 15:29 ` Paul Moore
2019-05-29 15:34 ` Tycho Andersen
2019-05-29 16:03 ` Paul Moore
2019-05-29 22:28 ` Tycho Andersen
2019-05-29 22:39 ` Paul Moore
2019-05-30 17:09 ` Serge E. Hallyn
2019-05-30 19:29 ` Paul Moore
2019-05-30 21:29 ` Tycho Andersen
2019-05-30 23:26 ` Paul Moore
2019-05-31 0:20 ` Richard Guy Briggs
2019-05-31 12:44 ` Paul Moore
2019-06-03 20:24 ` Steve Grubb
2019-06-18 22:12 ` Paul Moore
2019-06-18 22:46 ` Richard Guy Briggs
2019-07-08 18:12 ` Richard Guy Briggs
2019-07-08 20:43 ` Paul Moore
2019-07-15 21:09 ` Paul Moore
2019-07-16 15:37 ` Richard Guy Briggs
2019-07-16 16:08 ` Paul Moore
2019-07-16 16:26 ` Richard Guy Briggs
2019-07-08 18:05 ` Richard Guy Briggs [this message]
2019-07-15 21:04 ` Paul Moore
2019-07-16 22:03 ` Richard Guy Briggs
2019-07-16 23:30 ` Paul Moore
2019-07-18 0:51 ` Richard Guy Briggs
2019-07-18 21:52 ` Paul Moore
2019-07-19 16:00 ` Eric W. Biederman
2019-07-20 2:19 ` James Bottomley
2019-07-19 15:32 ` Eric W. Biederman
2019-07-08 17:51 ` Richard Guy Briggs
2019-07-15 20:38 ` Paul Moore
2019-07-16 19:38 ` Richard Guy Briggs
2019-07-16 21:39 ` Paul Moore
2019-07-19 16:07 ` Eric W. Biederman
2019-04-09 3:39 ` [PATCH ghak90 V6 03/10] audit: read container ID of a process Richard Guy Briggs
2019-07-19 16:03 ` Eric W. Biederman
2019-07-19 17:05 ` Richard Guy Briggs
2019-04-09 3:39 ` [PATCH ghak90 V6 04/10] audit: log container info of syscalls Richard Guy Briggs
2019-05-29 22:15 ` Paul Moore
2019-05-30 13:08 ` Ondrej Mosnacek
2019-05-30 14:08 ` Richard Guy Briggs
2019-05-30 14:34 ` Paul Moore
2019-04-09 3:39 ` [PATCH ghak90 V6 05/10] audit: add contid support for signalling the audit daemon Richard Guy Briggs
2019-04-09 12:57 ` Ondrej Mosnacek
2019-04-09 13:40 ` Paul Moore
2019-04-09 13:48 ` Neil Horman
2019-04-09 14:00 ` Ondrej Mosnacek
2019-04-09 14:07 ` Paul Moore
2019-04-09 13:53 ` Richard Guy Briggs
2019-04-09 14:08 ` Paul Moore
2019-04-09 13:46 ` Neil Horman
2019-04-09 3:39 ` [PATCH ghak90 V6 06/10] audit: add support for non-syscall auxiliary records Richard Guy Briggs
2019-04-09 3:39 ` [PATCH ghak90 V6 07/10] audit: add containerid support for user records Richard Guy Briggs
2019-04-09 3:39 ` [PATCH ghak90 V6 08/10] audit: add containerid filtering Richard Guy Briggs
2019-05-29 22:16 ` Paul Moore
2019-05-30 14:19 ` Richard Guy Briggs
2019-05-30 14:34 ` Paul Moore
2019-05-30 20:37 ` Richard Guy Briggs
2019-05-30 20:45 ` Paul Moore
2019-05-30 21:10 ` Richard Guy Briggs
2019-04-09 3:39 ` [PATCH ghak90 V6 09/10] audit: add support for containerid to network namespaces Richard Guy Briggs
2019-05-29 22:17 ` Paul Moore
2019-05-30 14:15 ` Richard Guy Briggs
2019-05-30 14:32 ` Paul Moore
2019-04-09 3:39 ` [PATCH ghak90 V6 10/10] audit: NETFILTER_PKT: record each container ID associated with a netNS Richard Guy Briggs
2019-04-11 11:31 ` [PATCH ghak90 V6 00/10] audit: implement container identifier Richard Guy Briggs
2019-04-22 11:38 ` Neil Horman
2019-04-22 13:49 ` Paul Moore
2019-04-23 10:28 ` Neil Horman
2019-05-28 21:53 ` Daniel Walsh
2019-05-28 22:25 ` Richard Guy Briggs
2019-05-28 22:26 ` Paul Moore
2019-05-28 23:00 ` Steve Grubb
2019-05-29 0:43 ` Richard Guy Briggs
2019-05-29 12:02 ` Daniel Walsh
2019-05-29 13:17 ` Paul Moore
2019-05-29 14:07 ` Daniel Walsh
2019-05-29 14:33 ` Paul Moore
2019-05-29 13:14 ` Paul Moore
2019-05-29 22:26 ` Paul Moore
2019-05-30 13:08 ` Steve Grubb
2019-05-30 13:35 ` Paul Moore
2019-05-30 14:08 ` Richard Guy Briggs
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