On Thu, Jul 09, 2020 at 12:44:25PM -0700, Doug Hardie wrote: > > On 9 July 2020, at 08:13, Mark Johnston <ma...@freebsd.org> wrote: > > > > Hi, > > > > 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. > > > > 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. > > > > 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. > > > > 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.
To be clear, with the proposed change SCTP can be loaded at boot by adding a single line: sctp_load="YES" to /boot/loader.conf, or kld_list="sctp" to /etc/rc.conf. Also, the change will not be present in a release until 13.0 or possibly 12.2, which provides plenty of time, and the release notes will reflect the change. I was really looking for objections pointing out that a dynamically loaded SCTP stack would prevent or inhibit some workflow. Relying on being able to configure systems from memory rather than using a checklist or some automated configuration management does not seem to be a good reason for keeping SCTP in the kernel. > What is going to happen if you run an application that uses SCTP and the > module is not loaded? An attempt to create an SCTP socket will fail with EPROTONOSUPPORT, "Protocol not supported". > What will remind me how to fix the issue? I am not likely to remember about > this 6 months from now. Hopefully "protocol not supported" is a sufficiently descriptive error message. _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
