Re: [PATCH] Don't audit SECCOMP_KILL/RET_ERRNO when syscall auditing is disabled

[Andi Kleen]

On Sun, Apr 10, 2016 at 10:30:10PM -0400, Paul Moore wrote:
> On Sun, Apr 10, 2016 at 6:31 PM, Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote:
> > On Sun, Apr 10, 2016 at 06:17:53PM -0400, Paul Moore wrote:
> >> On Sat, Apr 9, 2016 at 10:41 PM, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
> >> >> What kernel version are you using?  I believe we fixed that in Linux
> >> >> 4.5 with the following:
> >> >
> >> > This is 4.6-rc2.
> >> >>
> >> >>   commit 96368701e1c89057bbf39222e965161c68a85b4b
> >> >>   From: Paul Moore <pmoore@xxxxxxxxxx>
> >> >>   Date: Wed, 13 Jan 2016 10:18:55 -0400 (09:18 -0500)
> >> >>
> >> >>   audit: force seccomp event logging to honor the audit_enabled flag
> >> >
> >> > No you didn't fix it because audit_enabled is always enabled by systemd
> >> > for user space auditing, see the original description of my patch.
> >>
> >> [NOTE: adding the audit list to the CC line]
> >
> > This mailing list is marked subscriber only in MAINTAINERS so I
> > intentionally didn't add it. It's unlikely that my emails
> > will make it through.
> 
> Steve Grubb checks it on a regular basis and approves anything
> remotely audit related.  Please make use of it in the future; it's
> listed in MAINTAINERS for a reason.

Nothing has appeared by now. A mailing list that does not allow
real time discussion is fairly useless. 

Dropped again.

> >> If you are interested, I started tracking this issue at the link below:
> >>
> >>  * https://github.com/linux-audit/audit-kernel/issues/13
> >
> > Making it a sysctl is fine for me as long as it is disabled by default
> > so that user space doesn't need to be modified to make seccomp
> > stop spamming.
> >
> > Audit should always be opt-in, not opt-out.
> 
> From my perspective, you, or rather systemd in your case, is opting in
> by enabling audit.

It wants an audit channel, but not random kernel subsystems
unconditionally spamming the logs. If it wanted the later it would
set audit rules.

> 
> > However I think making it conditional on syscall auditing like
> > in my patch is equivalent and much simpler.
> >
> > If you really insist on the sysctl I can send patch.
> 
> As I said earlier, I haven't given this a lot of thought as of yet,
> but so far I like the sysctl approach much more than the patch you
> sent earlier.

Ok I'm sending an updated patch.

-Andi
-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.