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

[Jiri Kosina]

On Wed, 7 Mar 2018, Andy Lutomirski wrote:

> Wow, this was a long time ago.  

Oh yeah; but it now resurfaced on our side, as we are of course receiving 
a lot of requests with respect to making syscall performance great again 
:)

> From memory and a bit of email diving, there are two reasons.
> 
> 1. The probably was partially solved (by Oleg, IIRC) by making auditctl 
>    -a task,never cause newly spawned tasks to not suck.  Yes, it's a 
>    very partial solution.  After considerable nagging, I got Fedora to 
>    default to -a task,never.

Hm, right; that's a bit inconvenient, because it takes each and every 
vendor having to realize this option, and put it in. Making kernel do the 
right thing automatically sounds like a better option to me.

> 2. This patch, as is, may be a bit problematic.  In particular, if one 
>    task changes the audit rules while another task is in the middle of 
>    the syscall, then it's too late to audit that syscall correctly.  
>    This could be seen as a bug or it could be seen as being just fine.

I don't think this should be a problem, given the fact that the whole 
timing/ordering is not predictable anyway due to scheduling.

Paul, what do you think?

Thanks,

-- 
Jiri Kosina
SUSE Labs