From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A45B1C35240 for ; Sun, 26 Jan 2020 04:10:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7994A2071E for ; Sun, 26 Jan 2020 04:10:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729224AbgAZEKX (ORCPT ); Sat, 25 Jan 2020 23:10:23 -0500 Received: from mout-p-102.mailbox.org ([80.241.56.152]:45856 "EHLO mout-p-102.mailbox.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728842AbgAZEKX (ORCPT ); Sat, 25 Jan 2020 23:10:23 -0500 Received: from smtp1.mailbox.org (smtp1.mailbox.org [80.241.60.240]) (using TLSv1.2 with cipher ECDHE-RSA-CHACHA20-POLY1305 (256/256 bits)) (No client certificate requested) by mout-p-102.mailbox.org (Postfix) with ESMTPS id 484ztj4mYPzKmmG; Sun, 26 Jan 2020 05:10:21 +0100 (CET) X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from smtp1.mailbox.org ([80.241.60.240]) by spamfilter01.heinlein-hosting.de (spamfilter01.heinlein-hosting.de [80.241.56.115]) (amavisd-new, port 10030) with ESMTP id cyVBuGgdlFHA; Sun, 26 Jan 2020 05:10:18 +0100 (CET) Date: Sun, 26 Jan 2020 15:10:09 +1100 From: Aleksa Sarai To: Sargun Dhillon Cc: Tycho Andersen , LKML , Linux Containers , Linux API , Linux FS-devel Mailing List , Christian Brauner Subject: Re: [PATCH 3/4] seccomp: Add SECCOMP_USER_NOTIF_FLAG_PIDFD to get pidfd on listener trap Message-ID: <20200126041009.wubw4t5iaypf6bkk@yavin.dot.cyphar.com> References: <20200124091743.3357-1-sargun@sargun.me> <20200124091743.3357-4-sargun@sargun.me> <20200124180332.GA4151@cisco> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="b547hxjkssbqtln5" Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --b547hxjkssbqtln5 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2020-01-24, Sargun Dhillon wrote: > On Fri, Jan 24, 2020 at 10:03 AM Tycho Andersen 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 trigge= re > > > 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 >=20 > 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. Possibly unpopular proposal -- would it make sense to just store the pidfd_open(2) flags rather than coming up with our own set for SECCOMP_USER_NOTIF? If/when pidfds are expanded to include non-leaders there will be a corresponding flag for pidfd_open(2). Something like: struct seccomp_notif { __u64 id; __u32 pid; __u32 flags; struct seccomp_data data; __u64 pidfd_flags; // or __u32 -- not sure what Christian plans __u32 pidfd; __u32 __padding; }; This does mean there'll be an additional flags field, but I think it's a slightly more consistent way to indicate "SECCOMP_USER_NOTIF_FLAG_PIDFD implies a pidfd_open(2) on the traced task". --=20 Aleksa Sarai Senior Software Engineer (Containers) SUSE Linux GmbH --b547hxjkssbqtln5 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQSxZm6dtfE8gxLLfYqdlLljIbnQEgUCXi0RHgAKCRCdlLljIbnQ EhRBAP9kCf5WxYqsddLpbde2EDbbHMYUsQFCJzkEKqYgxO8v6gEAodewLdV9xQjY t35JSLzrhWvvTNnq1B+Vvdyvj9MvDwA= =bVpa -----END PGP SIGNATURE----- --b547hxjkssbqtln5--