PAM_ELOGIND(8)

NAME
pam_elogind - Register user sessions in the elogind login manager

SYNOPSIS

pam_elogind.so

DESCRIPTION

pam_elogind registers user sessions with the elogind(8) login manager, and hence the elogind control group hierarchy.

On login, this module ensures the following:

    1. If it does not exist yet, the user runtime directory /run/user/$UID is either created or mounted as new "tmpfs" file system with quota applied, 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 was 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. If enabled in logind.conf(5) (KillUserProcesses=), all processes of the session are terminated. If the last concurrent session of a user ends, elogind removes the user's runtime state after the configured stop delay.

On logout, this module ensures the following:

    1. If the last concurrent session of a user ends, the user runtime directory /run/user/$UID and all its contents are removed, too.

If elogind is not running or cannot be contacted, this module does nothing and immediately returns PAM_SUCCESS.

OPTIONS

The following options are understood:

class=
    Takes a string argument which sets the session class. The XDG_SESSION_CLASS environment variable (see below) takes precedence. One of "user", "greeter", "lock-screen" or "background". See sd_session_get_class(3) for details about the session class.

    Added in version 197.

type=
    Takes a string argument which sets the session type. The XDG_SESSION_TYPE environment variable (see below) takes precedence. One of "unspecified", "tty", "x11", "wayland" or "mir". See sd_session_get_type(3) for details about the session type.

    Added in version 209.

desktop=
    Takes a single, short identifier string for the desktop environment. The XDG_SESSION_DESKTOP environment variable (see below) takes precedence. This may be used to indicate the session desktop used, where this applies and if this information is available. For example: "GNOME", or "KDE". It is recommended to use the same identifiers and capitalization as for $XDG_CURRENT_DESKTOP, as defined by the Desktop Entry Specification[1]. (However, note that the option only takes a single item, and not a colon-separated list like $XDG_CURRENT_DESKTOP.) See sd_session_get_desktop(3) for further details.

    Added in version 240.

default-capability-bounding-set=, default-capability-ambient-set=
    Takes a comma-separated list of process capabilities (e.g. CAP_WAKE_ALARM, CAP_BLOCK_SUSPEND, ...) to set for the invoked session's processes. See capabilities(7) for details on the capabilities concept. If not specified, the default bounding set is left as is (i.e. usually contains the full set of capabilities). The default ambient set is set to CAP_WAKE_ALARM for regular users if the PAM session is associated with a local seat. Otherwise, defaults to the empty set.

    Added in version 254.

debug[=]
    Takes an optional boolean argument. If yes or without the argument, the module will log debugging information as it operates.

MODULE TYPES PROVIDED

Only session is provided.

ENVIRONMENT

The following environment variables are initialized by the module and available to the processes of the user's session:

$XDG_SESSION_ID
    A short session identifier, suitable to be used in filenames. 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. Combine this ID with the boot identifier, as returned by sd_id128_get_boot(3), for a globally unique identifier.

$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 the user's 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. For further details, see the XDG Base Directory Specification[2]. $XDG_RUNTIME_DIR is not set if the current user is not the original user of the session.

The following environment variables are read by the module and may be used by the PAM service to pass metadata to the module. If these variables are not set when the PAM module is invoked but can be determined otherwise they are set by the module, so that these variables are initialized for the session and applications if known at all.

$XDG_SESSION_TYPE
    The session type. This may be used instead of type= on the module parameter line, and is usually preferred.

    Added in version 209.

$XDG_SESSION_CLASS
    The session class. This may be used instead of class= on the module parameter line, and is usually preferred.

    Added in version 209.

$XDG_SESSION_DESKTOP
    The desktop identifier. This may be used instead of desktop= on the module parameter line, and is usually preferred.

    Added in version 209.

$XDG_SEAT
    The seat name the session shall be registered for, if any.

    Added in version 209.

$XDG_VTNR
    The VT number the session shall be registered for, if any. (Only applies to seats with a VT available, such as "seat0")

    Added in version 209.

If not set, pam_elogind will initialize $XDG_SEAT and $XDG_VTNR based on the $DISPLAY variable (if the latter is set).

EXAMPLE

Here's an example PAM configuration fragment that allows users sessions to be managed by elogind:

    #%PAM-1.0
    auth            required        pam_shells.so
    auth            required        pam_nologin.so
    auth            include         system-auth
    account         required        pam_access.so
    account         required        pam_nologin.so
    account         required        pam_time.so
    account         include         system-auth
    password        include         system-auth
    session         optional        pam_loginuid.so
    session         required        pam_env.so envfile=/etc/profile.env
    session         optional        pam_lastlog.so silent
    session         include         system-auth
    session         optional        pam_motd.so motd=/etc/motd
    session         optional        pam_mail.so
    -session  optional   pam_elogind.so

SEE ALSO

logind.conf(5), loginctl(1), pam.conf(5), pam.d(5), pam(8), pam_loginuid(8),

NOTES

1.  Desktop Entry Specification
    https://standards.freedesktop.org/desktop-entry-spec/latest/

2.  XDG Base Directory Specification
    https://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html