[PATCH v28 22/25] Audit: Add record for multiple process LSM attributes

[Paul Moore]

On Thu, Aug 19, 2021 at 6:41 PM Casey Schaufler <casey at schaufler-ca.com> wrote:
> On 8/18/2021 5:56 PM, Casey Schaufler wrote:
> > On 8/18/2021 5:47 PM, Paul Moore wrote:
> >> ...
> >> I just spent a few minutes tracing the code paths up from audit
> >> through netlink and then through the socket layer and I'm not seeing
> >> anything obvious where the path differs from any other syscall;
> >> current->audit_context *should* be valid just like any other syscall.
> >> However, I do have to ask, are you only seeing these audit records
> >> with a current->audit_context equal to NULL during early boot?
> >
> > Nope. Sorry.
>
> It looks as if all of the NULL audit_context cases are for either
> auditd or systemd. Given what the events are, this isn't especially
> surprising.

I think we may be back to the "early boot" theory.

Unless you explicitly enable audit on the kernel cmdline, e.g.
"audit=1", processes started before userspace enables audit will not
have a properly allocated audit_context; see the "if
(likely(!audit_ever_enabled))" check at the top of audit_alloc() for
the reason why.

I could be wrong here, but I suspect if you add "audit=1" to your
kernel command line those remaining cases of NULL audit_contexts will
resolve themselves.  If not, we still have work to do ... well, I mean
we still have (different) work to do even if this solves the mystery,
it's just that we can now explain what you are seeing :)

-- 
paul moore
www.paul-moore.com