From owner-freebsd-net@freebsd.org Thu Jul 9 19:44:32 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 665193544EC for ; Thu, 9 Jul 2020 19:44:32 +0000 (UTC) (envelope-from SRS0=nAK9=AU=mail.sermon-archive.info=doug@sermon-archive.info) Received: from mail.sermon-archive.info (sermon-archive.info [71.177.216.148]) by mx1.freebsd.org (Postfix) with ESMTP id 4B2mpR4J1bz4WxZ; Thu, 9 Jul 2020 19:44:31 +0000 (UTC) (envelope-from SRS0=nAK9=AU=mail.sermon-archive.info=doug@sermon-archive.info) Received: from [10.0.1.251] (mini [10.0.1.251]) by mail.sermon-archive.info (Postfix) with ESMTPSA id 4B2mpK2fG8z2fjRM; Thu, 9 Jul 2020 12:44:25 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.14\)) Subject: Re: making SCTP loadable and removing it from GENERIC From: Doug Hardie In-Reply-To: <20200709151300.GC8947@raichu> Date: Thu, 9 Jul 2020 12:44:25 -0700 Cc: freebsd-net@freebsd.org, tuexen@freebsd.org Content-Transfer-Encoding: quoted-printable Message-Id: <63F4446F-DECF-4DE8-99CA-EC8755A5D4A1@mail.sermon-archive.info> References: <20200709151300.GC8947@raichu> To: Mark Johnston X-Mailer: Apple Mail (2.3445.104.14) X-Virus-Scanned: clamav-milter 0.101.4 at mail X-Virus-Status: Clean X-Rspamd-Queue-Id: 4B2mpR4J1bz4WxZ X-Spamd-Bar: - Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of SRS0=nAK9=AU=mail.sermon-archive.info=doug@sermon-archive.info designates 71.177.216.148 as permitted sender) smtp.mailfrom=SRS0=nAK9=AU=mail.sermon-archive.info=doug@sermon-archive.info X-Spamd-Result: default: False [-1.63 / 15.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.001]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; MV_CASE(0.50)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; R_SPF_ALLOW(-0.20)[+ip4:71.177.216.148]; DMARC_NA(0.00)[lafn.org: no valid DMARC record]; TO_DN_SOME(0.00)[]; NEURAL_HAM_LONG(-1.02)[-1.018]; NEURAL_HAM_SHORT(-0.21)[-0.208]; FORGED_SENDER(0.30)[bc979@lafn.org,SRS0=nAK9=AU=mail.sermon-archive.info=doug@sermon-archive.info]; RCVD_NO_TLS_LAST(0.10)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:5650, ipnet:71.177.216.0/23, country:US]; FROM_NEQ_ENVFROM(0.00)[bc979@lafn.org,SRS0=nAK9=AU=mail.sermon-archive.info=doug@sermon-archive.info]; RCVD_COUNT_TWO(0.00)[2] 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 19:44:32 -0000 > 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. 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 me how to fix the issue? I am = not likely to remember about this 6 months from now. -- Doug=