linux-kernel - Re: ntp audit spew.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 24 Sep 2019 09:50:46 -0400
From:   Richard Guy Briggs <rgb@...hat.com>
To:     Paul Moore <paul@...l-moore.com>
Cc:     Dave Jones <davej@...emonkey.org.uk>, linux-audit@...hat.com,
        Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: ntp audit spew.

On 2019-09-23 23:01, Paul Moore wrote:
> On Mon, Sep 23, 2019 at 5:00 PM Richard Guy Briggs <rgb@...hat.com> wrote:
> > On 2019-09-23 12:14, Paul Moore wrote:
> > > On Mon, Sep 23, 2019 at 11:50 AM Dave Jones <davej@...emonkey.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.

> paul moore

- RGB

--
Richard Guy Briggs <rgb@...hat.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