Bug 70214

Archlinux x64
systemd 208

The "/usr/lib/systemd/systemd --user" process exists after user logout. This prevents unmounting volumes listed in the pam_mount.xml.

This affects logins to DE as well as remote logins via ssh.

The issue exists in systemd 207 and 208. Some of previous versions work fine.

Isn't there a deeper - fundamental bug:

The pam infrastructure normally is used to get credentials only.
But pam_mount does something that systemd-user should do.
And it does it by using very special xml config files!

For the user/admin this means breakage in two regards:
- a mount NOT done,registered by using Systemd
- very different scheme and logic to configure this

I've tried to create a user-specific systemd.mount unit and put it in $HOME/.config/systemd/user.

This solution does not work because the "mount" command requires the root privileges. "User=root" and "Group=root" options do not help - and it is good, I do not think that these options shall be acceptable in the user-specific units.

I believe that mounting can be achieved by writing user-specific systemd.serivce unit and tricks with sudoers and shell scripts. But it is not a graceful way I think.

User managers should now go away:
http://cgit.freedesktop.org/systemd/systemd/commit/?id=63966da.
If not, please reopen.

Retested on Archlinux systemd-208-3
Test flow: "tst" user logs in via ssh and logs out.

No user prosesses remains after logout but the volume is still mounted.

pam_mount debug=1
Journald logs:

<login>

Jan 10 15:36:30 n102805 sshd[32375]: (pam_mount.c:365): pam_mount 2.14: entering auth stage
Jan 10 15:36:30 n102805 sshd[32375]: Accepted password for tst from 127.0.0.1 port 43475 ssh2
Jan 10 15:36:30 n102805 sshd[32375]: (pam_mount.c:568): pam_mount 2.14: entering session stage
Jan 10 15:36:30 n102805 sshd[32375]: (mount.c:263): Mount info: globalconf, user=tst <volume fstyp...sh=0
Jan 10 15:36:30 n102805 sshd[32375]: (mount.c:660): Password will be sent to helper as-is.
Jan 10 15:36:30 n102805 sshd[32375]: command: 'mount' '-p0' '-osize=256M,uid=tst' '-ttmpfs' 'tmpfs...che'
Jan 10 15:36:30 n102805 sshd[32375]: (mount.c:68): Messages from underlying mount program:
Jan 10 15:36:30 n102805 sshd[32375]: (mount.c:72): mount: --pass-fd is no longer supported

***

Jan 10 15:36:30 n102805 sshd[32375]: command: 'pmvarrun' '-u' 'tst' '-o' '1'
Jan 10 15:36:30 n102805 sshd[32375]: (pam_mount.c:441): pmvarrun says login count is 1
Jan 10 15:36:30 n102805 sshd[32375]: (pam_mount.c:660): done opening session (ret=0)
Jan 10 15:36:30 n102805 sshd[32375]: pam_unix(sshd:session): session opened for user tst by (uid=0)
Jan 10 15:36:30 n102805 systemd[1]: Starting user-1001.slice.
Jan 10 15:36:30 n102805 systemd[1]: Created slice user-1001.slice.
Jan 10 15:36:30 n102805 systemd[1]: Starting User Manager for 1001...
Jan 10 15:36:30 n102805 systemd[1]: Starting Session 74 of user tst.
Jan 10 15:36:30 n102805 systemd-logind[355]: New session 74 of user tst.
Jan 10 15:36:30 n102805 systemd[1]: Started Session 74 of user tst.
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:568): pam_mount 2.14: entering session stage
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:173): conv->conv(...): Conversation error
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:477): warning: could not obtain password interactively either
Jan 10 15:36:30 n102805 systemd[32402]: (mount.c:263): Mount info: globalconf, user=tst <volume fstype="tmpfs" server="(null)" path="tmpfs" mountpoint="/home/tst/.cache" cipher="(null)" fskeypath="(null)" fskeyc
Jan 10 15:36:30 n102805 systemd[32402]: (mount.c:624): tmpfs already seems to be mounted at /home/tst/.cache, skipping
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:173): conv->conv(...): Conversation error
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:477): warning: could not obtain password interactively either
Jan 10 15:36:30 n102805 systemd[32402]: command: 'pmvarrun' '-u' 'tst' '-o' '1'
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:568): pam_mount 2.14: entering session stage
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:173): conv->conv(...): Conversation error
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:477): warning: could not obtain password interactively either
Jan 10 15:36:30 n102805 systemd[32402]: (mount.c:263): Mount info: globalconf, user=tst <volume fstype="tmpfs" server="(null)" path="tmpfs" mountpoint="/home/tst/.cache" cipher="(null)" fskeypath="(null)" fskeyc
Jan 10 15:36:30 n102805 systemd[32402]: (mount.c:624): tmpfs already seems to be mounted at /home/tst/.cache, skipping
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:173): conv->conv(...): Conversation error
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:477): warning: could not obtain password interactively either
Jan 10 15:36:30 n102805 systemd[32402]: command: 'pmvarrun' '-u' 'tst' '-o' '1'
Jan 10 15:36:30 n102805 systemd[32402]: (pmvarrun.c:254): parsed count value 1
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:441): pmvarrun says login count is 2
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:660): done opening session (ret=0)
Jan 10 15:36:30 n102805 systemd[32402]: pam_unix(systemd-user:session): session opened for user tst by (uid=0)
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:441): pmvarrun says login count is 2
Jan 10 15:36:30 n102805 systemd[32402]: (pam_mount.c:660): done opening session (ret=0)
Jan 10 15:36:30 n102805 systemd[32402]: Failed to open private bus connection: Failed to connect to socket /run/user/1001/dbus/user_bus_socket: No such file or directory
Jan 10 15:36:30 n102805 systemd[32402]: Mounted /sys/kernel/config.
Jan 10 15:36:30 n102805 systemd[32402]: Mounted /sys/fs/fuse/connections.
Jan 10 15:36:30 n102805 systemd[32402]: Stopped target Sound Card.
Jan 10 15:36:30 n102805 systemd[32402]: Starting Default.
Jan 10 15:36:30 n102805 systemd[32402]: Reached target Default.
Jan 10 15:36:30 n102805 systemd[32402]: Startup finished in 11ms.
Jan 10 15:36:30 n102805 systemd[1]: Started User Manager for 1001.


<logout>

Jan 10 15:38:13 n102805 sshd[32404]: Received disconnect from 127.0.0.1: 11: disconnected by user
Jan 10 15:38:13 n102805 sshd[32375]: (pam_mount.c:706): received order to close things
Jan 10 15:38:13 n102805 sshd[32375]: command: 'pmvarrun' '-u' 'tst' '-o' '-1'
Jan 10 15:38:13 n102805 sshd[32375]: (pam_mount.c:441): pmvarrun says login count is 1
Jan 10 15:38:13 n102805 sshd[32375]: (pam_mount.c:735): tst seems to have other remaining open sessions
Jan 10 15:38:13 n102805 sshd[32375]: (pam_mount.c:743): pam_mount execution complete
Jan 10 15:38:13 n102805 sshd[32375]: pam_unix(sshd:session): session closed for user tst
Jan 10 15:38:13 n102805 sshd[32375]: (pam_mount.c:116): Clean global config (0)
Jan 10 15:38:13 n102805 sshd[32375]: (pam_mount.c:133): clean system authtok=0x1cc1a90 (0)
Jan 10 15:38:13 n102805 systemd-logind[355]: Removed session 74.
Jan 10 15:38:13 n102805 systemd[1]: Stopping User Manager for 1001...
Jan 10 15:38:13 n102805 systemd[32408]: (pam_mount.c:116): Clean global config (1073741824)
Jan 10 15:38:13 n102805 systemd[32402]: (pam_mount.c:116): Clean global config (1073741824)
Jan 10 15:38:13 n102805 systemd[32402]: Stopping Default.
Jan 10 15:38:13 n102805 systemd[32402]: Stopped target Default.
Jan 10 15:38:13 n102805 systemd[32402]: Starting Shutdown.
Jan 10 15:38:13 n102805 systemd[32402]: Reached target Shutdown.
Jan 10 15:38:13 n102805 systemd[32402]: Starting Exit the Session...
Jan 10 15:38:13 n102805 systemd[1]: Stopped User Manager for 1001.
Jan 10 15:38:13 n102805 systemd[1]: Stopping user-1001.slice.
Jan 10 15:38:13 n102805 systemd[1]: Removed slice user-1001.slice.


On login:
The sshd mounts the volume and increases /var/run/pam_mount/tst by '1'.
The systemd makes the same things. Volume is mounted already and /var/run/pam_mount/tst is increased by '1' again. Now it is equal to '2'.
(Duplicated logs from systemd/pam_mount. Is it a problem?)

On logout:
The sshd closes session. The pam_sm_close_session() (pam_mount.c) function is called. It decreases /var/run/pam_mount/tst by '-1'. But the value is still positive ('1') and no unmounting is performed.
The systemd closes session but the pam_sm_close_session() function is not called and the volume remains mounted.

pam_mount really should learn to deal with abnormal PAM session termination. For example pam_systemd/logind track sessions with a dangling fifo to make this robust.