Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20190923155041.GA14807@codemonkey.org.uk> <CAHC9VhTyz7fd+iQaymVXUGFe3ZA5Z_WkJeY_snDYiZ9GP6gCOA@mail.gmail.com>
 <20190923210021.5vfc2fo4wopennj5@madcap2.tricolour.ca> <CAHC9VhQPvS7mfmeomRLJ+SyXk=tZprSJQ9Ays3qr=+rqd=L16Q@mail.gmail.com>
 <20190924135046.kkt5hntbjpcampwr@madcap2.tricolour.ca> <CAHC9VhTJ53OSpNDLHMMrv65NFv7MK1XQt1zXPwd7nnAPo3rG0Q@mail.gmail.com>
In-Reply-To: <CAHC9VhTJ53OSpNDLHMMrv65NFv7MK1XQt1zXPwd7nnAPo3rG0Q@mail.gmail.com>
From:   Paul Moore <paul@paul-moore.com>
Date:   Thu, 26 Sep 2019 11:50:07 -0400
Message-ID: <CAHC9VhR+iWur_0T06=Y0Cxn6HG16NOLUiNo3yyyNo_6bkCNFXQ@mail.gmail.com>
Subject: Re: ntp audit spew.
To:     Dave Jones <davej@codemonkey.org.uk>
Cc:     linux-audit@redhat.com, Richard Guy Briggs <rgb@redhat.com>,
        Linux Kernel <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, Sep 24, 2019 at 1:05 PM Paul Moore <paul@paul-moore.com> wrote:
> On Tue, Sep 24, 2019 at 9:50 AM Richard Guy Briggs <rgb@redhat.com> wrote:
> > On 2019-09-23 23:01, Paul Moore wrote:
> > > On Mon, Sep 23, 2019 at 5:00 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > > On 2019-09-23 12:14, Paul Moore wrote:
> > > > > On Mon, Sep 23, 2019 at 11:50 AM Dave Jones <davej@codemonkey.org.uk> wrote:
> > > > > >
> > > > > > I have some hosts that are constantly spewing audit messages like so:
> > > > > >
> > > > > > [46897.591182] audit: type=1333 audit(1569250288.663:220): op=offset old=2543677901372 new=2980866217213
> > > > > > [46897.591184] audit: type=1333 audit(1569250288.663:221): op=freq old=-2443166611284 new=-2436281764244
> > > >
> > > > Odd.  It appears these two above should have the same serial number and
> > > > should be accompanied by a syscall record.  It appears that it has no
> > > > context to update to connect the two records.  Is it possible it is not
> > > > being called in a task context?  If that were the case though, I'd
> > > > expect audit_dummy_context() to return 1...
> > >
> > > Yeah, I'm a little confused with these messages too.  As you pointed
> > > out, the different serial numbers imply that the audit_context is NULL
> > > and if the audit_context is NULL I would have expected it to fail the
> > > audit_dummy_context() check in audit_ntp_log().  I'm looking at this
> > > with tired eyes at the moment, so I'm likely missing something, but I
> > > just don't see it right now ...
> > >
> > > What is even more confusing is that I don't see this issue on my test systems.
> > >
> > > > Checking audit_enabled should not be necessary but might fix the
> > > > problem, but still not explain why we're getting these records.
> > >
> > > I'd like to understand why this is happening before we start changing the code.
> >
> > Absolutely.
> >
> > This looks like a similar issue to the AUDIT_NETFILTER_CFG issue where
> > we get a lone record unconnected to a syscall when one of the netfilter
> > table initialization (ipv4 filter) is linked into the kernel rather than
> > compiled as a module, so it is run in kernel context at boot rather than
> > in user context as a module load later.  This is why I ask if it is
> > being run by a kernel thread rather than a user task, perhaps using a
> > syscall function call internally.
>
> I don't see where in the code that could happen, but I agree that it
> looks like it; maybe I'm just missing a code path somewhere.
>
> Is anyone else seeing these records?  Granted my audit test systems
> are running chrony, not ntp, but the syscalls/behaviors should be
> similar and I can't seem to recreate this.

Dave, can you provide any additional information on the systems where
you are seeing this?  Kernel, userspace, distro, relevant configs,
etc.

-- 
paul moore
www.paul-moore.com