From owner-freebsd-net@freebsd.org Thu Jul 9 20:00:20 2020 Return-Path: Delivered-To: freebsd-net@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 213FC354B81 for ; Thu, 9 Jul 2020 20:00:20 +0000 (UTC) (envelope-from tuexen@freebsd.org) Received: from drew.franken.de (mail-n.franken.de [193.175.24.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.franken.de", Issuer "Sectigo RSA Domain Validation Secure Server CA" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4B2n8g6r4kz4Y0x; Thu, 9 Jul 2020 20:00:19 +0000 (UTC) (envelope-from tuexen@freebsd.org) Received: from mb.fritz.box (ip4d15f5fc.dynamic.kabel-deutschland.de [77.21.245.252]) (Authenticated sender: macmic) by mail-n.franken.de (Postfix) with ESMTPSA id 2BE847220B82B; Thu, 9 Jul 2020 22:00:17 +0200 (CEST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 13.4 \(3608.80.23.2.2\)) Subject: Re: making SCTP loadable and removing it from GENERIC From: Michael Tuexen In-Reply-To: <63F4446F-DECF-4DE8-99CA-EC8755A5D4A1@mail.sermon-archive.info> Date: Thu, 9 Jul 2020 22:00:16 +0200 Cc: Mark Johnston , freebsd-net@freebsd.org Content-Transfer-Encoding: quoted-printable Message-Id: <5C210E52-0447-450C-B515-70FDC5EA29F4@freebsd.org> References: <20200709151300.GC8947@raichu> <63F4446F-DECF-4DE8-99CA-EC8755A5D4A1@mail.sermon-archive.info> To: Doug Hardie X-Mailer: Apple Mail (2.3608.80.23.2.2) X-Spam-Status: No, score=-2.9 required=5.0 tests=ALL_TRUSTED,BAYES_00 autolearn=disabled version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on mail-n.franken.de X-Rspamd-Queue-Id: 4B2n8g6r4kz4Y0x X-Spamd-Bar: / Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [0.00 / 15.00]; local_wl_from(0.00)[freebsd.org]; ASN(0.00)[asn:680, ipnet:193.174.0.0/15, country:DE] X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 09 Jul 2020 20:00:20 -0000 > On 9. Jul 2020, at 21:44, Doug Hardie wrote: >=20 >> On 9 July 2020, at 08:13, Mark Johnston wrote: >>=20 >> Hi, >>=20 >> I spent some time working on making it possible to load the SCTP = stack >> as a kernel module, the same as we do today with IPSec. There is one >> patch remaining to be committed before that can be done in head. One >> caveat is that the module can't be unloaded, as some work is needed = to >> make this safe. However, this obviously isn't a regression. >>=20 >> The work is based on the observations that: >> 1) the in-kernel SCTP stack is not widely used (I know that the same >> code is used in some userland applications), and >> 2) the SCTP stack is quite large, most FreeBSD kernel developers are >> unfamiliar with it, and bugs in it can easily lead to security = holes. >>=20 >> Michael has done a lot of work to fix issues in the SCTP code, >> particularly those found by syzkaller, but given that in-kernel SCTP = has >> few users (almost certainly fewer than IPSec), it seems reasonable to >> require users to opt in to having an SCTP stack with a simple = "kldload >> sctp". Thus, once the last patch is committed I would like to = propose >> removing "options SCTP" from GENERIC kernel configs in head, = replacing >> it with "options SCTP_SUPPORT" to enable sctp.ko to be loaded. >>=20 >> I am wondering if anyone has any objections to or concerns about this >> proposal. Any feedback is appreciated. >=20 > I have a number of systems using SCTP. It is a key part of a = distributed application. As a user of SCTP, I have a slight objection = to removing it from the kernel. It would require me to remember when = setting up a new system to enable that. I am not likely to remember. = What is going to happen if you run an application that uses SCTP and the = module is not loaded? What will remind=20 The socket() call would fail. What then happens depend on the error = handling in your application. > me how to fix the issue? I am not likely to remember about this 6 = months from now. I'm not sure, but I guess Mark is planning to MFC the changes to = stable/12. So you would test this when upgrading to 12.2, I guess. I suggested to document what user have to do (assuming they read UPGRADING and it gets documented there. Best regards Michael >=20 > -- Doug