Ubuntu Manpage: pam_systemd - Register user sessions in the systemd login manager

Provided by: libpam-systemd_204-5ubuntu20.31_amd64

NAME

       pam_systemd - Register user sessions in the systemd login manager

SYNOPSIS

       pam_systemd.so

DESCRIPTION

       pam_systemd registers user sessions in the systemd login manager systemd-
       logind.service(8), and hence the systemd control group hierarchy.

       On login, this module ensures the following:

        1. If it does not exist yet, the user runtime directory /run/user/$USER is created and
           its ownership changed to the user that is logging in.

        2. The $XDG_SESSION_ID environment variable is initialized. If auditing is available and
           pam_loginuid.so run before this module (which is highly recommended), the variable is
           initialized from the auditing session id (/proc/self/sessionid). Otherwise an
           independent session counter is used.

        3. A new control group /user/$USER/$XDG_SESSION_ID is created and the login process moved
           into it.

       On logout, this module ensures the following:

        1. If $XDG_SESSION_ID is set and kill-session-processes=1 specified, all remaining
           processes in the /user/$USER/$XDG_SESSION_ID control group are killed and the control
           group is removed.

        2. If the last subgroup of the /user/$USER control group was removed the $XDG_RUNTIME_DIR
           directory and all its contents are removed, too.

       If the system was not booted up with systemd as init system, this module does nothing and
       immediately returns PAM_SUCCESS.

OPTIONS

The following options are understood:

kill-session-processes=
Takes a boolean argument. If true, all processes created by the user during his
session and from his session will be terminated when he logs out from his session.

kill-only-users=
Takes a comma separated list of user names or numeric user ids as argument. If this
option is used the effect of the kill-session-processes= options will apply only to
the listed users. If this option is not used the option applies to all local users.
Note that kill-exclude-users= takes precedence over this list and is hence subtracted
from the list specified here.

kill-exclude-users=
Takes a comma separated list of user names or numeric user ids as argument. Users
listed in this argument will not be subject to the effect of kill-session-processes=.
Note that this option takes precedence over kill-only-users=, and hence whatever is
listed for kill-exclude-users= is guaranteed to never be killed by this PAM module,
independent of any other configuration setting.

controllers=
Takes a comma separated list of control group controllers in which hierarchies a
user/session control group will be created by default for each user logging in, in
addition to the control group in the named 'name=systemd' hierarchy. If omitted,
defaults to an empty list.

reset-controllers=
Takes a comma separated list of control group controllers in which hierarchies the
logged in processes will be reset to the root control group.

class=
Takes a string argument which sets the session class. The XDG_SESSION_CLASS
environmental variable takes precedence.

debug=
Takes a boolean argument. If yes, the module will log debugging information as it
operates.

Note that setting kill-session-processes=1 will break tools like screen(1).

Note that kill-session-processes=1 is a stricter version of KillUserProcesses=1 which may
be configured system-wide in logind.conf(5). The former kills processes of a session as
soon as it ends, the latter kills processes as soon as the last session of the user ends.

If the options are omitted they default to kill-session-processes=0, kill-only-users=,
kill-exclude-users=, controllers=, reset-controllers=, debug=no.

MODULE TYPES PROVIDED

       Only session is provided.

ENVIRONMENT

       The following environment variables are set for the processes of the user's session:

       $XDG_SESSION_ID
           A session identifier, suitable to be used in file names. The string itself should be
           considered opaque, although often it is just the audit session ID as reported by
           /proc/self/sessionid. Each ID will be assigned only once during machine uptime. It may
           hence be used to uniquely label files or other resources of this session.

       $XDG_RUNTIME_DIR
           Path to a user-private user-writable directory that is bound to the user login time on
           the machine. It is automatically created the first time a user logs in and removed on
           his final logout. If a user logs in twice at the same time, both sessions will see the
           same $XDG_RUNTIME_DIR and the same contents. If a user logs in once, then logs out
           again, and logs in again, the directory contents will have been lost in between, but
           applications should not rely on this behavior and must be able to deal with stale
           files. To store session-private data in this directory the user should include the
           value of $XDG_SESSION_ID in the filename. This directory shall be used for runtime
           file system objects such as AF_UNIX sockets, FIFOs, PID files and similar. It is
           guaranteed that this directory is local and offers the greatest possible file system
           feature set the operating system provides.

EXAMPLE

           #%PAM-1.0
           auth       required     pam_unix.so
           auth       required     pam_nologin.so
           account    required     pam_unix.so
           password   required     pam_unix.so
           session    required     pam_unix.so
           session    required     pam_loginuid.so
           session    required     pam_systemd.so kill-session-processes=1