Re: ntp audit spew.

From: Steve Grubb <sgrubb@redhat.com>
To: linux-audit@redhat.com
Subject: Re: ntp audit spew.
Date: Tue, 24 Sep 2019 09:30:20 -0400	[thread overview]
Message-ID: <74733970.gcqqMRRzBB@x2> (raw)
In-Reply-To: <d5d92540ca5aab8916ac4d93f6b5677ab52d2e7d.camel@redhat.com>

On Monday, September 23, 2019 3:49:52 PM EDT Eric Paris wrote:
> Is this the thing where systemd is listening on the multicast netlink
> socket and causes everything to come out kmesg as well?

Almost, it actually enables audit without knowing anything about the end
user's wishes:

https://github.com/systemd/systemd/blob/master/src/journal/journald-audit.c#L458

-Steve

> On Mon, 2019-09-23 at 15:49 -0400, Dave Jones wrote:
> > On Mon, Sep 23, 2019 at 02:57:08PM -0400, Paul Moore wrote:
> >  > On Mon, Sep 23, 2019 at 12:58 PM Dave Jones <
> > 
> > davej@codemonkey.org.uk> wrote:
> >  > > On Mon, Sep 23, 2019 at 12:14:14PM -0400, 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
> > 
> >  > >  > > [48850.604005] audit: type=1333 audit(1569252241.675:222):
> > op=offset old=1850302393317 new=3190241577926
> > 
> >  > >  > > [48850.604008] audit: type=1333 audit(1569252241.675:223):
> > op=freq old=-2436281764244 new=-2413071187316
> > 
> >  > >  > > [49926.567270] audit: type=1333 audit(1569253317.638:224):
> > op=offset old=2453141035832 new=2372389610455
> > 
> >  > >  > > [49926.567273] audit: type=1333 audit(1569253317.638:225):
> > op=freq old=-2413071187316 new=-2403561671476
> > 
> >  > >  > > This gets emitted every time ntp makes an adjustment, which
> > 
> > is apparently very frequent on some hosts.
> > 
> >  > >  > > Audit isn't even enabled on these machines.
> >  > >  > > 
> >  > >  > > # auditctl -l
> >  > >  > > No rules
> >  > >  > 
> >  > >  > What happens when you run 'auditctl -a never,task'?  That
> > 
> > *should*
> > 
> >  > >  > silence those messages as the audit_ntp_log() function has
> > 
> > the
> > 
> >  > >  > requisite audit_dummy_context() check.
> >  > > 
> >  > > They still get emitted.
> >  > > 
> >  > >  > FWIW, this is the distro
> >  > >  > default for many (most? all?) distros; for example, check
> >  > >  > /etc/audit/audit.rules on a stock Fedora system.
> >  > > 
> >  > > As these machines aren't using audit, they aren't running auditd
> > 
> > either.
> > 
> >  > > Essentially: nothing enables audit, but the kernel side
> > 
> > continues to log
> > 
> >  > > ntp regardless (no other audit messages seem to do this).
> >  > 
> >  > What does your kernel command line look like?  Do you have
> > 
> > "audit=1"
> > 
> >  > somewhere in there?
> > 
> > nope.
> > 
> > ro root=LABEL=/ biosdevname=0 net.ifnames=0 fsck.repair=yes
> > systemd.gpt_auto=0 pcie_pme=nomsi ipv6.autoconf=0 erst_disable
> > crashkernel=128M console=tty0 console=ttyS1,57600
> > intel_iommu=tboot_noforce
> > 
> > 	Dave
> 
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