[PATCH] audit: set TIF_AUDIT_SYSCALL only if audit filter has been populated

[Jiri Kosina]

On Wed, 14 Mar 2018, Andy Lutomirski wrote:

> > Yes...I wished I was in on the beginning of this discussion. Here's the
> > problem. We need all tasks auditable unless specifically dismissed as
> > uninteresting. This would be a task,never rule.
> >
> > The way we look at it, is if it boots with audit=1, then we know auditd
> > is expected to run at some point. So, we need all tasks to stay
> > auditable. If they weren't and auditd enabled auditing, then we'd need
> > to walk the whole proctable and stab TIF_AUDIT_SYSCALL into every
> > process in the system. It was decided that this is too ugly.
> 
> When was that decided?  That's what this patch does.

I'd like to see some more justification as well.

Namely, if I compare "setting TIF_AUDIT_SYSCALL for every process on a 
need-to-be-so basis" to "we always go through the slow path and 
pessimistically assume that audit is enabled and has reasonable ruleset 
loaded", I have my own (different) opinion of what is too ugly.

Thanks,

-- 
Jiri Kosina
SUSE Labs