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From: Christian Brauner <christian.brauner@ubuntu.com>
To: Sargun Dhillon <sargun@sargun.me>
Cc: Tycho Andersen <tycho@tycho.ws>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux Containers <containers@lists.linux-foundation.org>,
	Linux API <linux-api@vger.kernel.org>,
	Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH 3/4] seccomp: Add SECCOMP_USER_NOTIF_FLAG_PIDFD to get pidfd on listener trap
Date: Fri, 15 May 2020 13:58:21 +0200	[thread overview]
Message-ID: <20200515115821.5qvkaeuxzklhikuo@wittgenstein> (raw)
In-Reply-To: <CAMp4zn_Xv2iicmH2Nc4-EZceD7T8AFe9PQRNX4bNEiAuoKs+vA@mail.gmail.com>

On Fri, May 15, 2020 at 04:49:14AM -0700, Sargun Dhillon wrote:
> On Sat, Jan 25, 2020 at 9:42 PM Tycho Andersen <tycho@tycho.ws> wrote:
> 
> > On Fri, Jan 24, 2020 at 12:09:37PM -0800, Sargun Dhillon wrote:
> > > On Fri, Jan 24, 2020 at 10:03 AM Tycho Andersen <tycho@tycho.ws> wrote:
> > > >
> > > > On Fri, Jan 24, 2020 at 01:17:42AM -0800, Sargun Dhillon wrote:
> > > > > Currently, this just opens the group leader of the thread that
> > triggere
> > > > > the event, as pidfds (currently) are limited to group leaders.
> > > >
> > > > I don't love the semantics of this; when they're not limited to thread
> > > > group leaders any more, we won't be able to change this. Is that work
> > > > far off?
> > > >
> > > > Tycho
> > >
> > > We would be able to change this in the future if we introduced a flag
> > like
> > > SECCOMP_USER_NOTIF_FLAG_PIDFD_THREAD which would send a
> > > pidfd that's for the thread, and not just the group leader. The flag
> > could
> > > either be XOR with SECCOMP_USER_NOTIF_FLAG_PIDFD, or
> > > could require both. Alternatively, we can rename
> > > SECCOMP_USER_NOTIF_FLAG_PIDFD to
> > > SECCOMP_USER_NOTIF_FLAG_GROUP_LEADER_PIDFD.
> >
> > Ok, but then isn't this just another temporary API? Seems like it's
> > worth waiting until the Right Way exists.
> >
> > Tycho
> >
> 
> It's been a few months. It does not appear like much progress has been made
> moving away from
> pidfd being only useful for leaders.
> 
> I would either like to respin this patch, or at a minimum, include the
> process group leader pid number
> in the seccomp notification, to simplify things for tracers.

I'd prefer if you went with the second option where you include the
process group leader pid number.
I'm against adding countless ways of producing pidfds through various
unrelated apis. The api is still quite fresh so I'd like to not overdo
it.

Christian

  parent reply	other threads:[~2020-05-15 11:58 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-24  9:17 [PATCH 0/4] Add the ability to get a pidfd on seccomp user notifications Sargun Dhillon
2020-01-24  9:17 ` [PATCH 1/4] pid: Add pidfd_create_file helper Sargun Dhillon
2020-01-24  9:17 ` [PATCH 2/4] fork: Use newly created " Sargun Dhillon
2020-01-24  9:17 ` [PATCH 3/4] seccomp: Add SECCOMP_USER_NOTIF_FLAG_PIDFD to get pidfd on listener trap Sargun Dhillon
2020-01-24 18:03   ` Tycho Andersen
2020-01-24 20:09     ` Sargun Dhillon
2020-01-26  4:10       ` Aleksa Sarai
2020-01-26  5:42       ` Tycho Andersen
     [not found]         ` <CAMp4zn_Xv2iicmH2Nc4-EZceD7T8AFe9PQRNX4bNEiAuoKs+vA@mail.gmail.com>
2020-05-15 11:58           ` Christian Brauner [this message]
2020-01-26  4:03   ` Aleksa Sarai
2020-01-26  4:14     ` Aleksa Sarai
2020-01-27  5:06       ` Sargun Dhillon
2020-01-24  9:17 ` [PATCH 4/4] selftests/seccomp: test SECCOMP_USER_NOTIF_FLAG_PIDFD Sargun Dhillon

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