Re: [PATCH ghak25 v5] audit: add subj creds to NETFILTER_CFG record to cover async unregister

From: Paul Moore <paul@paul-moore.com>
To: Richard Guy Briggs <rgb@redhat.com>
Cc: fw@strlen.de, LKML <linux-kernel@vger.kernel.org>,
	Linux-Audit Mailing List <linux-audit@redhat.com>,
	netfilter-devel@vger.kernel.org, twoerner@redhat.com,
	Eric Paris <eparis@parisplace.org>,
	tgraf@infradead.org
Subject: Re: [PATCH ghak25 v5] audit: add subj creds to NETFILTER_CFG record to cover async unregister
Date: Tue, 19 May 2020 15:59:05 -0400	[thread overview]
Message-ID: <CAHC9VhQRSwTURYZ2dL_YWqi-xnPfFGN_Aef73mip=eYNVfObRw@mail.gmail.com> (raw)
In-Reply-To: <20200519194457.nouzteqv2vpcqnta@madcap2.tricolour.ca>

On Tue, May 19, 2020 at 3:45 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> On 2020-05-19 15:18, Paul Moore wrote:
> > On Tue, May 19, 2020 at 11:31 AM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > Some table unregister actions seem to be initiated by the kernel to
> > > garbage collect unused tables that are not initiated by any userspace
> > > actions.  It was found to be necessary to add the subject credentials to
> > > cover this case to reveal the source of these actions.  A sample record:
> > >
> > > The tty, ses and exe fields have not been included since they are in the
> > > SYSCALL record and contain nothing useful in the non-user context.
> > >
> > >   type=NETFILTER_CFG msg=audit(2020-03-11 21:25:21.491:269) : table=nat family=bridge entries=0 op=unregister pid=153 uid=root auid=unset subj=system_u:system_r:kernel_t:s0 comm=kworker/u4:2
> >
> > Based on where things were left in the discussion on the previous
> > draft, I think it would be good if you could explain a bit why the uid
> > and auid fields are useful here.
>
> They aren't really useful here.  I was hoping to remove them given your
> reasoning, but I was having trouble guessing what you wanted even after
> asking for clarity.  Can you clarify what you would prefer to see in
> this patch?

/me heavily rolls eyes

In my last email to you I said:

"I think it is pointless to record the subject info in this record as we
either have that info from other records in the event or there is no
valid subject info to record."

... I also said:

"As I've mentioned in the thread above, including the auid was done as
a concession to Steve, I don't think it serves any useful purpose."

If phrases like "pointless to record the subject info" and "I don't
think it serves any useful purpose" leave you unsure about what to do,
I'm at a bit of a loss.

Drop the "uid" field.  Drop the "auid" field.  Hopefully those last
two statements should remove any ambiguity from your mind.

-- 
paul moore
www.paul-moore.com

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