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

On 8/20/2021 12:06 PM, Paul Moore wrote: > On Thu, Aug 19, 2021 at 6:41 PM Casey Schaufler <casey(a)schaufler-ca.com&gt; 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 :) Yup, adding "audit=1" to the command line appears to have gotten systemd an audit context. It looks like user space enabling audit doesn't assign an audit context to the existing systemd process.