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From:   Paul Moore <paul@paul-moore.com>
Date:   Fri, 13 Mar 2020 12:29:10 -0400
Message-ID: <CAHC9VhQoVOzy_b9W6h+kmizKr1rPkC4cy5aYoKT2i0ZgsceNDg@mail.gmail.com>
Subject: Re: [PATCH ghak90 V8 07/16] audit: add contid support for signalling
 the audit daemon
To:     Richard Guy Briggs <rgb@redhat.com>
Cc:     Steve Grubb <sgrubb@redhat.com>, linux-audit@redhat.com,
        nhorman@tuxdriver.com, linux-api@vger.kernel.org,
        containers@lists.linux-foundation.org,
        LKML <linux-kernel@vger.kernel.org>, dhowells@redhat.com,
        netfilter-devel@vger.kernel.org, ebiederm@xmission.com,
        simo@redhat.com, netdev@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, Eric Paris <eparis@parisplace.org>,
        mpatel@redhat.com, Serge Hallyn <serge@hallyn.com>
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On Thu, Mar 12, 2020 at 3:30 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> On 2020-02-13 16:44, Paul Moore wrote:
> > This is a bit of a thread-hijack, and for that I apologize, but
> > another thought crossed my mind while thinking about this issue
> > further ... Once we support multiple auditd instances, including the
> > necessary record routing and duplication/multiple-sends (the host
> > always sees *everything*), we will likely need to find a way to "trim"
> > the audit container ID (ACID) lists we send in the records.  The
> > auditd instance running on the host/initns will always see everything,
> > so it will want the full container ACID list; however an auditd
> > instance running inside a container really should only see the ACIDs
> > of any child containers.
>
> Agreed.  This should be easy to check and limit, preventing an auditd
> from seeing any contid that is a parent of its own contid.
>
> > For example, imagine a system where the host has containers 1 and 2,
> > each running an auditd instance.  Inside container 1 there are
> > containers A and B.  Inside container 2 there are containers Y and Z.
> > If an audit event is generated in container Z, I would expect the
> > host's auditd to see a ACID list of "1,Z" but container 1's auditd
> > should only see an ACID list of "Z".  The auditd running in container
> > 2 should not see the record at all (that will be relatively
> > straightforward).  Does that make sense?  Do we have the record
> > formats properly designed to handle this without too much problem (I'm
> > not entirely sure we do)?
>
> I completely agree and I believe we have record formats that are able to
> handle this already.

I'm not convinced we do.  What about the cases where we have a field
with a list of audit container IDs?  How do we handle that?

-- 
paul moore
www.paul-moore.com