From: Richard Guy Briggs <rgb@redhat.com>
To: Paul Moore <paul@paul-moore.com>
Cc: Linux-Audit Mailing List <linux-audit@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
netfilter-devel@vger.kernel.org, sgrubb@redhat.com,
Ondrej Mosnacek <omosnace@redhat.com>,
fw@strlen.de, 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 15:44:57 -0400 [thread overview]
Message-ID: <20200519194457.nouzteqv2vpcqnta@madcap2.tricolour.ca> (raw)
In-Reply-To: <CAHC9VhQYUooJbZ9tcOOwb=48LTjtnfo0g11vQuyLzoxdetaxnw@mail.gmail.com>
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? I was hoping to skip this extra patch revision which took
longer than hoped due to trying to guess what you wanted while working
yesterday during a public holiday to get this patch out in time for the
merge window.
A UID of 0="root" is really a bit misleading since while it is the most
trusted user running the most privileged level, the event wasn't
triggered by a user. It is the default value of that field. I did
think aloud that uid could be set by the kernel to run under a
particular user's id (like a daemon dropping capabilities and switching
user after setup to limit abuse), but the kernel is just a tracker for
these IDs and doesn't really know what they mean other than root. I saw
no reply to that idea. It was set to "root" which isn't unset or
unexpected, but granted is useless in this case.
You had offered that keeping auid was a concession to Steve so I kept it
in since I had the impression that is what you wanted to see. That
explanation seems pretty thin to include in a patch description if what
you are getting at in your sentence above.
I am willing to purge both if that is what you would prefer to accept in
the patch.
> paul moore
- 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:[~2020-05-19 19:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 15:30 [PATCH ghak25 v5] audit: add subj creds to NETFILTER_CFG record to cover async unregister Richard Guy Briggs
2020-05-19 19:18 ` Paul Moore
2020-05-19 19:44 ` Richard Guy Briggs [this message]
2020-05-19 19:59 ` Paul Moore
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