Re: [PATCH 03/26] signal: Do not perform permission checks when sending pdeath_signal

[Richard Weinberger]

Eric,

On Tue, Jun 6, 2017 at 9:03 PM, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
> This fixes and old old regression.  When Roland switched from
> sending pdeath_signal with send_sig() to send_group_sig_info
> it gained a permission check, and started taking the tasklist
> lock.  Roland earlier fixed the double taking of the tasklist
> lock in 3f2a0d1df938 ("[PATCH] fix pdeath_signal SMP locking")
> but pdeath_signal still performs an unnecessary permission
> check.
>
> Ordinarily I would be hesitant at fixing an ancient regression but
> a permission check for our parent sending to us is almost never
> likely to fail (so it is unlikely anyone has noticed), and it
> is stupid.  It makes absolutely no sense to see if our
> parent has permission to send us a signal we requested be
> sent to us.

Another side effect of this change is that audit_signal_info() is no longer
being called. AFAICT this is a user space visible change.

-- 
Thanks,
//richard