The audit "context" and when to expect it.

[Casey Schaufler]

On 5/29/2020 2:49 PM, Paul Moore wrote:
> On Fri, May 29, 2020 at 5:42 PM Casey Schaufler <casey at schaufler-ca.com> wrote:
>> On 5/29/2020 12:01 PM, Paul Moore wrote:
>>> On Fri, May 29, 2020 at 1:59 PM Casey Schaufler <casey at schaufler-ca.com> wrote:
>>>> What does a NULL audit context (e.g. ab->cxt == NULL) tell
>>>> me about the status of the audit buffer? It seems like it should
>>>> be telling me that the audit buffer is being created for some
>>>> purpose unrelated to the current task. And yet there are places
>>>> where information is pulled from the current task even when
>>>> the cxt is NULL.
>>> The simple answer is that a NULL audit_context indicates a standalone
>>> record, meaning a record with a unique timestamp so that it is not
>>> associated with any other records into an event.  If the audit_context
>>> it not NULL then the information in the context is used to group, or
>>> associate, all of the records sharing that context into a single
>>> event.
>> OK, so if I want a add a sub-record with the multiple secctx values
> Terminology nit-pick: there are "records" and "events", there is
> nothing we would call a sub-record.

Thanks. I stand corrected.

>   In the case you are referring to,
> this is a record which would always be part of a larger collection of
> records.  It's similar to a PATH record in that it doesn't make sense
> by itself, but when combined with the other records in an event, it
> provides useful information.
>
>> for the events that include a subject value I need to change those
>> events to use an audit_context. Is that going to introduce an
>> unacceptable memory or performance burden?
> No more so than any additional record.  Or rather, it seems like this
> is the only way to do what you want to do so I don't see a way around
> it.

That's what I'll do then. Thanks again.