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cdown

Member

From: London, England

Registered: 2013-02-09

Posts: 55

Website

[SOLVED] Instantiating systemd user sessions on new SSH login

I want systemd user sessions to be instantiated automatically on SSH login. It looks like this should just work out of the box, since `pam_systemd` is configured to optionally run by the default `/etc/pam.d/system-login` provided by `pambase`:

server % cat /etc/pam.d/system-login
#%PAM-1.0

auth       required   pam_tally.so         onerr=succeed file=/var/log/faillog
auth       required   pam_shells.so
auth       requisite  pam_nologin.so
auth       include    system-auth

account    required   pam_access.so
account    required   pam_nologin.so
account    include    system-auth

password   include    system-auth

session    optional   pam_loginuid.so
session    optional   pam_keyinit.so       force revoke
session    include    system-auth
session    optional   pam_motd.so          motd=/etc/motd
session    optional   pam_mail.so          dir=/var/spool/mail standard quiet
-session   optional   pam_systemd.so
session    required   pam_env.so

This, however, doesn't appear to do much:

laptop % ssh server
server % systemctl --user status
Failed to connect to bus: No such file or directory
server % loginctl list-sessions 
   SESSION        UID USER             SEAT             TTY             

0 sessions listed.

Looking at the journal for `systemd-logind` shows that it's not even being asked to create login sessions for non-root users:

server % sudo systemctl status systemd-logind
● systemd-logind.service - Login Service
   Loaded: loaded (/usr/lib/systemd/system/systemd-logind.service; static; vendor preset: disabled)
   Active: active (running) since Tue 2017-12-05 02:37:47 CET; 19h ago
     Docs: man:systemd-logind.service(8)
           man:logind.conf(5)
           https://www.freedesktop.org/wiki/Software/systemd/logind
           https://www.freedesktop.org/wiki/Software/systemd/multiseat
 Main PID: 290 (systemd-logind)
   Status: "Processing requests..."
    Tasks: 1 (limit: 4915)
   CGroup: /system.slice/systemd-logind.service
           └─290 /usr/lib/systemd/systemd-logind

Dec 05 02:37:47 tangsanjiao systemd[1]: Starting Login Service...
Dec 05 02:37:47 tangsanjiao systemd[1]: Started Login Service.
Dec 05 02:37:47 tangsanjiao systemd-logind[290]: New seat seat0.
Dec 05 02:37:47 tangsanjiao systemd-logind[290]: Watching system buttons on /dev/input/event3 (Power Button)
Dec 05 02:37:47 tangsanjiao systemd-logind[290]: Watching system buttons on /dev/input/event1 (Power Button)
Dec 05 02:37:47 tangsanjiao systemd-logind[290]: Watching system buttons on /dev/input/event2 (Sleep Button)
Dec 05 02:38:20 tangsanjiao systemd-logind[290]: New session c1 of user root.
Dec 05 02:38:56 tangsanjiao systemd-logind[290]: Removed session c1.
Dec 05 02:39:04 tangsanjiao systemd-logind[290]: New session c2 of user root.
Dec 05 02:39:05 tangsanjiao systemd-logind[290]: Removed session c2.

Any idea what's wrong here?

Last edited by cdown (2017-12-05 21:00:32)

cdown

Member

From: London, England

Registered: 2013-02-09

Posts: 55

Website

Re: [SOLVED] Instantiating systemd user sessions on new SSH login

Ah, I assumed sshd defaulted to using PAM, but to my surprise by default UsePAM is `no` in upstream sshd. That was easy to fix :-)

Last edited by cdown (2017-12-05 21:00:20)