I think Dan's summary above is very good. For clarification I would add a couple of points.
The issue is not just remote logins. xdm behaves in the same way, and the absence of a systemd-logind session may mean that sound is then unavailable to the user logged in at the console. (Mentioned to help people searching for local sound issues.) Comments 12 and 16 of bug #1915502 also mention ProtectHostname=no which I don't understand. My understanding of nscd is that, even on cache misses, it will perform the lookup itself, and, being a separate process outside the systemd- logind sandbox, it will succeed. I am not convinced that mandating the use of nscd would be a good idea though, especially as some distributions are moving away from it, e.g. https://fedoraproject.org/wiki/Changes/RemoveNSCD I suspect a lot of NIS/LDAP users do use some version of nscd, which is why there are not more people caught by this issue. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to openldap in Ubuntu. https://bugs.launchpad.net/bugs/1934393 Title: systemd-logind network access is blocked, and breaks remote authentication configurations Status in systemd: Fix Released Status in nis package in Ubuntu: Confirmed Status in openldap package in Ubuntu: Confirmed Status in systemd package in Ubuntu: Won't Fix Status in nis package in Debian: Fix Released Bug description: [impact] starting in focal, systemd-logind runs sandboxed without any network access, which breaks any configuration that uses remote servers for user data, e.g. ldap, nis, etc A more full discussion is available in the upstream bug report as well as the debian bug report, see other info section below [test case] many possible ways to reproduce this; there are reproducers in some of the bugs reported before that are caused by this, e.g. bug 1915502 or bug 1916235 [regression potential] failure to authenticate when using remote user data, incorrect authentication, security issues due to un-sandboxing of systemd-logind [scope] this is needed in f and later before focal, systemd-logind was not sandboxed so this did not apply [other info] this isn't actually a bug in systemd, this is a by-design security feature, and the intended upstream design is for systemd-logind to talk to systemd-userdb, so that systemd-logind can remain network- sandboxed while systemd-userdb performs any needed network access for user/auth data. However, Debian and Ubuntu don't enable/provide systemd-userdb, so that design does not work for Debian/Ubuntu. this also can cause systemd-udevd failures in some cases as well, apparently (based on upstream and debian discussion comments) For reference, upstream discussion around the systemd-logind sandboxing specifically: https://github.com/systemd/systemd/issues/7074 upstream updated doc PR explaining the upstream position: https://github.com/systemd/systemd/pull/7343 Debian bug report: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878625 To manage notifications about this bug go to: https://bugs.launchpad.net/systemd/+bug/1934393/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
