PAM_SYSTEMD(8) pam_systemd PAM_SYSTEMD(8)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
SEE ALSOsystemd(1), systemd-logind.service(8), logind.conf(5), loginctl(1),
pam.conf(5), pam.d(5), pam(8), pam_loginuid(8)systemd 204PAM_SYSTEMD(8)