Am 20.08.2018 um 16:59 schrieb Eugene Grosbein <eu...@grosbein.net>: > > 20.08.2018 21:47, Stefan Bethke wrote: > >> I have a Go program (acme-dns) that wants to bind 53, 80, and 443, and I’d >> rather have it run as a non-privileged user. The program doesn’t provide a >> facility to drop privs after binding the ports. I’m planning to run it in a >> jail. >> >> After some googling, it appears that a couple of years ago I should have >> been able to do: >> sysctl net.inet.ip.portrange.reservedhigh=0 >> and allow all processes to bind to „low“ ports. This does not work in my >> jails on a 11-stable host. >> >> $ sudo sysctl net.inet.ip.portrange.reservedhigh=0 >> net.inet.ip.portrange.reservedhigh: 1023 >> sysctl: net.inet.ip.portrange.reservedhigh=0: Operation not permitted >> >> Securelevel should not interfere: >> $ sysctl kern.securelevel >> kern.securelevel: -1 >> >> Is there a way to allow regular processes to bind to low ports? > > Yes. Just use mac_portacl kernel module: kldload mac_portacl > > Once loaded, it duplicates net.inet.ip.portrange.reservedhigh protection > with its own security.mac.portacl.port_high, so it's safe to disable > "reservedhigh" for whole system by running sysctl > net.inet.ip.portrange.reservedhigh=0 > for host. > > The trick is that mac_portacl provides a way to selectively give permission > for non-root UID > to bind low ports: > > security.mac.portacl.rules=uid:88:tcp:80,uid:88:tcp:443,uid:53:tcp:53,uid:53:udp:53 > > It works just fine for a host and I use it for name servers utilizing port 53 > for a box with dynamically created interfaces, so it may bind the port for > distinct IP addresses > after it dropped privilegies when new interface is created and get new IP > assigned. > > I have not tried it for a jails, though. Please try and respond.
Thanks, but do I understand correctly that the security.mac.portacl.rules are system-wide and not per-jail? I’m running ~10 jails on this host, and I don’t want to allow all of them to bind to low ports. Stefan -- Stefan Bethke <s...@lassitu.de> Fon +49 151 14070811 _______________________________________________ freebsd-stable@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
