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-rw-r--r--src/grp-login/pam_systemd/Makefile55
-rw-r--r--src/grp-login/pam_systemd/pam_systemd.c553
-rw-r--r--src/grp-login/pam_systemd/pam_systemd.sym15
-rw-r--r--src/grp-login/pam_systemd/pam_systemd.xml296
4 files changed, 919 insertions, 0 deletions
diff --git a/src/grp-login/pam_systemd/Makefile b/src/grp-login/pam_systemd/Makefile
new file mode 100644
index 0000000000..56cbe98570
--- /dev/null
+++ b/src/grp-login/pam_systemd/Makefile
@@ -0,0 +1,55 @@
+# -*- Mode: makefile; indent-tabs-mode: t -*-
+#
+# This file is part of systemd.
+#
+# Copyright 2010-2012 Lennart Poettering
+# Copyright 2010-2012 Kay Sievers
+# Copyright 2013 Zbigniew Jędrzejewski-Szmek
+# Copyright 2013 David Strauss
+# Copyright 2016 Luke Shumaker
+#
+# systemd is free software; you can redistribute it and/or modify it
+# under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation; either version 2.1 of the License, or
+# (at your option) any later version.
+#
+# systemd is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with systemd; If not, see <http://www.gnu.org/licenses/>.
+include $(dir $(lastword $(MAKEFILE_LIST)))/../../../config.mk
+include $(topsrcdir)/build-aux/Makefile.head.mk
+
+ifneq ($(HAVE_PAM),)
+pam_systemd_la_SOURCES = \
+ src/login/pam_systemd.sym \
+ src/login/pam_systemd.c
+
+pam_systemd_la_CFLAGS = \
+ $(PAM_CFLAGS)
+
+pam_systemd_la_LDFLAGS = \
+ -module \
+ -export-dynamic \
+ -avoid-version \
+ -shared \
+ -Wl,--version-script=$(srcdir)/pam_systemd.sym
+
+pam_systemd_la_LIBADD = \
+ libsystemd-shared.la \
+ $(PAM_LIBS)
+
+pamlib_LTLIBRARIES = \
+ pam_systemd.la
+
+dist_pamconf_DATA = \
+ src/login/systemd-user
+
+EXTRA_DIST += \
+ src/login/systemd-user.m4
+endif # HAVE_PAM
+
+include $(topsrcdir)/build-aux/Makefile.tail.mk
diff --git a/src/grp-login/pam_systemd/pam_systemd.c b/src/grp-login/pam_systemd/pam_systemd.c
new file mode 100644
index 0000000000..fe1a2266b7
--- /dev/null
+++ b/src/grp-login/pam_systemd/pam_systemd.c
@@ -0,0 +1,553 @@
+/***
+ This file is part of systemd.
+
+ Copyright 2010 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <endian.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <security/_pam_macros.h>
+#include <security/pam_ext.h>
+#include <security/pam_misc.h>
+#include <security/pam_modules.h>
+#include <security/pam_modutil.h>
+#include <sys/file.h>
+
+#include "sd-bus/bus-common-errors.h"
+#include "sd-bus/bus-error.h"
+#include "sd-bus/bus-util.h"
+#include "systemd-basic/alloc-util.h"
+#include "systemd-basic/audit-util.h"
+#include "systemd-basic/def.h"
+#include "systemd-basic/fd-util.h"
+#include "systemd-basic/fileio.h"
+#include "systemd-basic/formats-util.h"
+#include "systemd-basic/hostname-util.h"
+#include "systemd-basic/login-util.h"
+#include "systemd-basic/macro.h"
+#include "systemd-basic/parse-util.h"
+#include "systemd-basic/socket-util.h"
+#include "systemd-basic/strv.h"
+#include "systemd-basic/terminal-util.h"
+#include "systemd-basic/util.h"
+
+static int parse_argv(
+ pam_handle_t *handle,
+ int argc, const char **argv,
+ const char **class,
+ const char **type,
+ bool *debug) {
+
+ unsigned i;
+
+ assert(argc >= 0);
+ assert(argc == 0 || argv);
+
+ for (i = 0; i < (unsigned) argc; i++) {
+ if (startswith(argv[i], "class=")) {
+ if (class)
+ *class = argv[i] + 6;
+
+ } else if (startswith(argv[i], "type=")) {
+ if (type)
+ *type = argv[i] + 5;
+
+ } else if (streq(argv[i], "debug")) {
+ if (debug)
+ *debug = true;
+
+ } else if (startswith(argv[i], "debug=")) {
+ int k;
+
+ k = parse_boolean(argv[i] + 6);
+ if (k < 0)
+ pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring.");
+ else if (debug)
+ *debug = k;
+
+ } else
+ pam_syslog(handle, LOG_WARNING, "Unknown parameter '%s', ignoring", argv[i]);
+ }
+
+ return 0;
+}
+
+static int get_user_data(
+ pam_handle_t *handle,
+ const char **ret_username,
+ struct passwd **ret_pw) {
+
+ const char *username = NULL;
+ struct passwd *pw = NULL;
+ int r;
+
+ assert(handle);
+ assert(ret_username);
+ assert(ret_pw);
+
+ r = pam_get_user(handle, &username, NULL);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to get user name.");
+ return r;
+ }
+
+ if (isempty(username)) {
+ pam_syslog(handle, LOG_ERR, "User name not valid.");
+ return PAM_AUTH_ERR;
+ }
+
+ pw = pam_modutil_getpwnam(handle, username);
+ if (!pw) {
+ pam_syslog(handle, LOG_ERR, "Failed to get user data.");
+ return PAM_USER_UNKNOWN;
+ }
+
+ *ret_pw = pw;
+ *ret_username = username;
+
+ return PAM_SUCCESS;
+}
+
+static int get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) {
+ union sockaddr_union sa = {
+ .un.sun_family = AF_UNIX,
+ };
+ _cleanup_free_ char *p = NULL, *tty = NULL;
+ _cleanup_close_ int fd = -1;
+ struct ucred ucred;
+ int v, r;
+
+ assert(display);
+ assert(vtnr);
+
+ /* We deduce the X11 socket from the display name, then use
+ * SO_PEERCRED to determine the X11 server process, ask for
+ * the controlling tty of that and if it's a VC then we know
+ * the seat and the virtual terminal. Sounds ugly, is only
+ * semi-ugly. */
+
+ r = socket_from_display(display, &p);
+ if (r < 0)
+ return r;
+ strncpy(sa.un.sun_path, p, sizeof(sa.un.sun_path)-1);
+
+ fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
+ if (fd < 0)
+ return -errno;
+
+ if (connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un)) < 0)
+ return -errno;
+
+ r = getpeercred(fd, &ucred);
+ if (r < 0)
+ return r;
+
+ r = get_ctty(ucred.pid, NULL, &tty);
+ if (r < 0)
+ return r;
+
+ v = vtnr_from_tty(tty);
+ if (v < 0)
+ return v;
+ else if (v == 0)
+ return -ENOENT;
+
+ if (seat)
+ *seat = "seat0";
+ *vtnr = (uint32_t) v;
+
+ return 0;
+}
+
+static int export_legacy_dbus_address(
+ pam_handle_t *handle,
+ uid_t uid,
+ const char *runtime) {
+
+ _cleanup_free_ char *s = NULL;
+ int r = PAM_BUF_ERR;
+
+ /* FIXME: We *really* should move the access() check into the
+ * daemons that spawn dbus-daemon, instead of forcing
+ * DBUS_SESSION_BUS_ADDRESS= here. */
+
+ s = strjoin(runtime, "/bus", NULL);
+ if (!s)
+ goto error;
+
+ if (access(s, F_OK) < 0)
+ return PAM_SUCCESS;
+
+ s = mfree(s);
+ if (asprintf(&s, UNIX_USER_BUS_ADDRESS_FMT, runtime) < 0)
+ goto error;
+
+ r = pam_misc_setenv(handle, "DBUS_SESSION_BUS_ADDRESS", s, 0);
+ if (r != PAM_SUCCESS)
+ goto error;
+
+ return PAM_SUCCESS;
+
+error:
+ pam_syslog(handle, LOG_ERR, "Failed to set bus variable.");
+ return r;
+}
+
+_public_ PAM_EXTERN int pam_sm_open_session(
+ pam_handle_t *handle,
+ int flags,
+ int argc, const char **argv) {
+
+ _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+ _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+ const char
+ *username, *id, *object_path, *runtime_path,
+ *service = NULL,
+ *tty = NULL, *display = NULL,
+ *remote_user = NULL, *remote_host = NULL,
+ *seat = NULL,
+ *type = NULL, *class = NULL,
+ *class_pam = NULL, *type_pam = NULL, *cvtnr = NULL, *desktop = NULL;
+ _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+ int session_fd = -1, existing, r;
+ bool debug = false, remote;
+ struct passwd *pw;
+ uint32_t vtnr = 0;
+ uid_t original_uid;
+
+ assert(handle);
+
+ /* Make this a NOP on non-logind systems */
+ if (!logind_running())
+ return PAM_SUCCESS;
+
+ if (parse_argv(handle,
+ argc, argv,
+ &class_pam,
+ &type_pam,
+ &debug) < 0)
+ return PAM_SESSION_ERR;
+
+ if (debug)
+ pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing");
+
+ r = get_user_data(handle, &username, &pw);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to get user data.");
+ return r;
+ }
+
+ /* Make sure we don't enter a loop by talking to
+ * systemd-logind when it is actually waiting for the
+ * background to finish start-up. If the service is
+ * "systemd-user" we simply set XDG_RUNTIME_DIR and
+ * leave. */
+
+ pam_get_item(handle, PAM_SERVICE, (const void**) &service);
+ if (streq_ptr(service, "systemd-user")) {
+ _cleanup_free_ char *rt = NULL;
+
+ if (asprintf(&rt, "/run/user/"UID_FMT, pw->pw_uid) < 0)
+ return PAM_BUF_ERR;
+
+ r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
+ return r;
+ }
+
+ r = export_legacy_dbus_address(handle, pw->pw_uid, rt);
+ if (r != PAM_SUCCESS)
+ return r;
+
+ return PAM_SUCCESS;
+ }
+
+ /* Otherwise, we ask logind to create a session for us */
+
+ pam_get_item(handle, PAM_XDISPLAY, (const void**) &display);
+ pam_get_item(handle, PAM_TTY, (const void**) &tty);
+ pam_get_item(handle, PAM_RUSER, (const void**) &remote_user);
+ pam_get_item(handle, PAM_RHOST, (const void**) &remote_host);
+
+ seat = pam_getenv(handle, "XDG_SEAT");
+ if (isempty(seat))
+ seat = getenv("XDG_SEAT");
+
+ cvtnr = pam_getenv(handle, "XDG_VTNR");
+ if (isempty(cvtnr))
+ cvtnr = getenv("XDG_VTNR");
+
+ type = pam_getenv(handle, "XDG_SESSION_TYPE");
+ if (isempty(type))
+ type = getenv("XDG_SESSION_TYPE");
+ if (isempty(type))
+ type = type_pam;
+
+ class = pam_getenv(handle, "XDG_SESSION_CLASS");
+ if (isempty(class))
+ class = getenv("XDG_SESSION_CLASS");
+ if (isempty(class))
+ class = class_pam;
+
+ desktop = pam_getenv(handle, "XDG_SESSION_DESKTOP");
+ if (isempty(desktop))
+ desktop = getenv("XDG_SESSION_DESKTOP");
+
+ tty = strempty(tty);
+
+ if (strchr(tty, ':')) {
+ /* A tty with a colon is usually an X11 display,
+ * placed there to show up in utmp. We rearrange
+ * things and don't pretend that an X display was a
+ * tty. */
+
+ if (isempty(display))
+ display = tty;
+ tty = NULL;
+ } else if (streq(tty, "cron")) {
+ /* cron has been setting PAM_TTY to "cron" for a very
+ * long time and it probably shouldn't stop doing that
+ * for compatibility reasons. */
+ type = "unspecified";
+ class = "background";
+ tty = NULL;
+ } else if (streq(tty, "ssh")) {
+ /* ssh has been setting PAM_TTY to "ssh" for a very
+ * long time and probably shouldn't stop doing that
+ * for compatibility reasons. */
+ type ="tty";
+ class = "user";
+ tty = NULL;
+ }
+
+ /* If this fails vtnr will be 0, that's intended */
+ if (!isempty(cvtnr))
+ (void) safe_atou32(cvtnr, &vtnr);
+
+ if (!isempty(display) && !vtnr) {
+ if (isempty(seat))
+ get_seat_from_display(display, &seat, &vtnr);
+ else if (streq(seat, "seat0"))
+ get_seat_from_display(display, NULL, &vtnr);
+ }
+
+ if (seat && !streq(seat, "seat0") && vtnr != 0) {
+ pam_syslog(handle, LOG_DEBUG, "Ignoring vtnr %"PRIu32" for %s which is not seat0", vtnr, seat);
+ vtnr = 0;
+ }
+
+ if (isempty(type))
+ type = !isempty(display) ? "x11" :
+ !isempty(tty) ? "tty" : "unspecified";
+
+ if (isempty(class))
+ class = streq(type, "unspecified") ? "background" : "user";
+
+ remote = !isempty(remote_host) && !is_localhost(remote_host);
+
+ /* Talk to logind over the message bus */
+
+ r = sd_bus_open_system(&bus);
+ if (r < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", strerror(-r));
+ return PAM_SESSION_ERR;
+ }
+
+ if (debug)
+ pam_syslog(handle, LOG_DEBUG, "Asking logind to create session: "
+ "uid="UID_FMT" pid="PID_FMT" service=%s type=%s class=%s desktop=%s seat=%s vtnr=%"PRIu32" tty=%s display=%s remote=%s remote_user=%s remote_host=%s",
+ pw->pw_uid, getpid(),
+ strempty(service),
+ type, class, strempty(desktop),
+ strempty(seat), vtnr, strempty(tty), strempty(display),
+ yes_no(remote), strempty(remote_user), strempty(remote_host));
+
+ r = sd_bus_call_method(bus,
+ "org.freedesktop.login1",
+ "/org/freedesktop/login1",
+ "org.freedesktop.login1.Manager",
+ "CreateSession",
+ &error,
+ &reply,
+ "uusssssussbssa(sv)",
+ (uint32_t) pw->pw_uid,
+ (uint32_t) getpid(),
+ service,
+ type,
+ class,
+ desktop,
+ seat,
+ vtnr,
+ tty,
+ display,
+ remote,
+ remote_user,
+ remote_host,
+ 0);
+ if (r < 0) {
+ if (sd_bus_error_has_name(&error, BUS_ERROR_SESSION_BUSY)) {
+ pam_syslog(handle, LOG_DEBUG, "Cannot create session: %s", bus_error_message(&error, r));
+ return PAM_SUCCESS;
+ } else {
+ pam_syslog(handle, LOG_ERR, "Failed to create session: %s", bus_error_message(&error, r));
+ return PAM_SYSTEM_ERR;
+ }
+ }
+
+ r = sd_bus_message_read(reply,
+ "soshusub",
+ &id,
+ &object_path,
+ &runtime_path,
+ &session_fd,
+ &original_uid,
+ &seat,
+ &vtnr,
+ &existing);
+ if (r < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to parse message: %s", strerror(-r));
+ return PAM_SESSION_ERR;
+ }
+
+ if (debug)
+ pam_syslog(handle, LOG_DEBUG, "Reply from logind: "
+ "id=%s object_path=%s runtime_path=%s session_fd=%d seat=%s vtnr=%u original_uid=%u",
+ id, object_path, runtime_path, session_fd, seat, vtnr, original_uid);
+
+ r = pam_misc_setenv(handle, "XDG_SESSION_ID", id, 0);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set session id.");
+ return r;
+ }
+
+ if (original_uid == pw->pw_uid) {
+ /* Don't set $XDG_RUNTIME_DIR if the user we now
+ * authenticated for does not match the original user
+ * of the session. We do this in order not to result
+ * in privileged apps clobbering the runtime directory
+ * unnecessarily. */
+
+ r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", runtime_path, 0);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
+ return r;
+ }
+
+ r = export_legacy_dbus_address(handle, pw->pw_uid, runtime_path);
+ if (r != PAM_SUCCESS)
+ return r;
+ }
+
+ if (!isempty(seat)) {
+ r = pam_misc_setenv(handle, "XDG_SEAT", seat, 0);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set seat.");
+ return r;
+ }
+ }
+
+ if (vtnr > 0) {
+ char buf[DECIMAL_STR_MAX(vtnr)];
+ sprintf(buf, "%u", vtnr);
+
+ r = pam_misc_setenv(handle, "XDG_VTNR", buf, 0);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set virtual terminal number.");
+ return r;
+ }
+ }
+
+ r = pam_set_data(handle, "systemd.existing", INT_TO_PTR(!!existing), NULL);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to install existing flag.");
+ return r;
+ }
+
+ if (session_fd >= 0) {
+ session_fd = fcntl(session_fd, F_DUPFD_CLOEXEC, 3);
+ if (session_fd < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to dup session fd: %m");
+ return PAM_SESSION_ERR;
+ }
+
+ r = pam_set_data(handle, "systemd.session-fd", FD_TO_PTR(session_fd), NULL);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to install session fd.");
+ safe_close(session_fd);
+ return r;
+ }
+ }
+
+ return PAM_SUCCESS;
+}
+
+_public_ PAM_EXTERN int pam_sm_close_session(
+ pam_handle_t *handle,
+ int flags,
+ int argc, const char **argv) {
+
+ _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+ _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+ const void *existing = NULL;
+ const char *id;
+ int r;
+
+ assert(handle);
+
+ /* Only release session if it wasn't pre-existing when we
+ * tried to create it */
+ pam_get_data(handle, "systemd.existing", &existing);
+
+ id = pam_getenv(handle, "XDG_SESSION_ID");
+ if (id && !existing) {
+
+ /* Before we go and close the FIFO we need to tell
+ * logind that this is a clean session shutdown, so
+ * that it doesn't just go and slaughter us
+ * immediately after closing the fd */
+
+ r = sd_bus_open_system(&bus);
+ if (r < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", strerror(-r));
+ return PAM_SESSION_ERR;
+ }
+
+ r = sd_bus_call_method(bus,
+ "org.freedesktop.login1",
+ "/org/freedesktop/login1",
+ "org.freedesktop.login1.Manager",
+ "ReleaseSession",
+ &error,
+ NULL,
+ "s",
+ id);
+ if (r < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to release session: %s", bus_error_message(&error, r));
+ return PAM_SESSION_ERR;
+ }
+ }
+
+ /* Note that we are knowingly leaking the FIFO fd here. This
+ * way, logind can watch us die. If we closed it here it would
+ * not have any clue when that is completed. Given that one
+ * cannot really have multiple PAM sessions open from the same
+ * process this means we will leak one FD at max. */
+
+ return PAM_SUCCESS;
+}
diff --git a/src/grp-login/pam_systemd/pam_systemd.sym b/src/grp-login/pam_systemd/pam_systemd.sym
new file mode 100644
index 0000000000..23ff75f688
--- /dev/null
+++ b/src/grp-login/pam_systemd/pam_systemd.sym
@@ -0,0 +1,15 @@
+/***
+ This file is part of systemd.
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+***/
+
+{
+global:
+ pam_sm_close_session;
+ pam_sm_open_session;
+local: *;
+};
diff --git a/src/grp-login/pam_systemd/pam_systemd.xml b/src/grp-login/pam_systemd/pam_systemd.xml
new file mode 100644
index 0000000000..ddda81bc90
--- /dev/null
+++ b/src/grp-login/pam_systemd/pam_systemd.xml
@@ -0,0 +1,296 @@
+<?xml version='1.0'?> <!--*-nxml-*-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+ "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+
+<!--
+ This file is part of systemd.
+
+ Copyright 2010 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+-->
+
+<refentry id="pam_systemd" conditional='HAVE_PAM'>
+
+ <refentryinfo>
+ <title>pam_systemd</title>
+ <productname>systemd</productname>
+
+ <authorgroup>
+ <author>
+ <contrib>Developer</contrib>
+ <firstname>Lennart</firstname>
+ <surname>Poettering</surname>
+ <email>lennart@poettering.net</email>
+ </author>
+ </authorgroup>
+ </refentryinfo>
+
+ <refmeta>
+ <refentrytitle>pam_systemd</refentrytitle>
+ <manvolnum>8</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>pam_systemd</refname>
+ <refpurpose>Register user sessions in the systemd login manager</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <para><filename>pam_systemd.so</filename></para>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para><command>pam_systemd</command> registers user sessions with
+ the systemd login manager
+ <citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ and hence the systemd control group hierarchy.</para>
+
+ <para>On login, this module ensures the following:</para>
+
+ <orderedlist>
+ <listitem><para>If it does not exist yet, the user runtime
+ directory <filename>/run/user/$USER</filename> is created and
+ its ownership changed to the user that is logging
+ in.</para></listitem>
+
+ <listitem><para>The <varname>$XDG_SESSION_ID</varname>
+ environment variable is initialized. If auditing is available
+ and <command>pam_loginuid.so</command> was run before this
+ module (which is highly recommended), the variable is
+ initialized from the auditing session id
+ (<filename>/proc/self/sessionid</filename>). Otherwise, an
+ independent session counter is used.</para></listitem>
+
+ <listitem><para>A new systemd scope unit is created for the
+ session. If this is the first concurrent session of the user, an
+ implicit slice below <filename>user.slice</filename> is
+ automatically created and the scope placed into it. An instance
+ of the system service <filename>user@.service</filename>, which
+ runs the systemd user manager instance, is started.
+ </para></listitem>
+ </orderedlist>
+
+ <para>On logout, this module ensures the following:</para>
+
+ <orderedlist>
+ <listitem><para>If enabled in
+ <citerefentry><refentrytitle>logind.conf</refentrytitle>
+ <manvolnum>5</manvolnum></citerefentry>, all processes of the
+ session are terminated. If the last concurrent session of a user
+ ends, the user's systemd instance will be terminated too, and so
+ will the user's slice unit.</para></listitem>
+
+ <listitem><para>If the last concurrent session of a user ends,
+ the <varname>$XDG_RUNTIME_DIR</varname> directory and all its
+ contents are removed, too.</para></listitem>
+ </orderedlist>
+
+ <para>If the system was not booted up with systemd as init system,
+ this module does nothing and immediately returns
+ <constant>PAM_SUCCESS</constant>.</para>
+
+ </refsect1>
+
+ <refsect1>
+ <title>Options</title>
+
+ <para>The following options are understood:</para>
+
+ <variablelist class='pam-directives'>
+
+ <varlistentry>
+ <term><option>class=</option></term>
+
+ <listitem><para>Takes a string argument which sets the session
+ class. The XDG_SESSION_CLASS environmental variable takes
+ precedence. One of
+ <literal>user</literal>,
+ <literal>greeter</literal>,
+ <literal>lock-screen</literal> or
+ <literal>background</literal>. See
+ <citerefentry><refentrytitle>sd_session_get_class</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ for details about the session class.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>type=</option></term>
+
+ <listitem><para>Takes a string argument which sets the session
+ type. The XDG_SESSION_TYPE environmental variable takes
+ precedence. One of
+ <literal>unspecified</literal>,
+ <literal>tty</literal>,
+ <literal>x11</literal>,
+ <literal>wayland</literal> or
+ <literal>mir</literal>. See
+ <citerefentry><refentrytitle>sd_session_get_type</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ for details about the session type.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>debug<optional>=</optional></option></term>
+
+ <listitem><para>Takes an optional
+ boolean argument. If yes or without
+ the argument, the module will log
+ debugging information as it
+ operates.</para></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Module Types Provided</title>
+
+ <para>Only <option>session</option> is provided.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Environment</title>
+
+ <para>The following environment variables are set for the
+ processes of the user's session:</para>
+
+ <variablelist class='environment-variables'>
+ <varlistentry>
+ <term><varname>$XDG_SESSION_ID</varname></term>
+
+ <listitem><para>A session identifier, suitable to be used in
+ filenames. The string itself should be considered opaque,
+ although often it is just the audit session ID as reported by
+ <filename>/proc/self/sessionid</filename>. Each ID will be
+ assigned only once during machine uptime. It may hence be used
+ to uniquely label files or other resources of this
+ session.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>$XDG_RUNTIME_DIR</varname></term>
+
+ <listitem><para>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
+ <varname>$XDG_RUNTIME_DIR</varname> and the same contents. If
+ a user logs in once, then logs out again, and logs in again,
+ the directory contents will have been lost in between, but
+ applications should not rely on this behavior and must be able
+ to deal with stale files. To store session-private data in
+ this directory, the user should include the value of
+ <varname>$XDG_SESSION_ID</varname> in the filename. This
+ directory shall be used for runtime file system objects such
+ as <constant>AF_UNIX</constant> 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 <ulink
+ url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG
+ Base Directory Specification</ulink>.</para></listitem>
+ </varlistentry>
+
+ </variablelist>
+
+ <para>The following environment variables are read by the module
+ and may be used by the PAM service to pass metadata to the
+ module:</para>
+
+ <variablelist class='environment-variables'>
+ <varlistentry>
+ <term><varname>$XDG_SESSION_TYPE</varname></term>
+
+ <listitem><para>The session type. This may be used instead of
+ <option>session=</option> on the module parameter line, and is
+ usually preferred.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>$XDG_SESSION_CLASS</varname></term>
+
+ <listitem><para>The session class. This may be used instead of
+ <option>class=</option> on the module parameter line, and is
+ usually preferred.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>$XDG_SESSION_DESKTOP</varname></term>
+
+ <listitem><para>A single, short identifier string for the
+ desktop environment. This may be used to indicate the session
+ desktop used, where this applies and if this information is
+ available. For example: <literal>GNOME</literal>, or
+ <literal>KDE</literal>. It is recommended to use the same
+ identifiers and capitalization as for
+ <varname>$XDG_CURRENT_DESKTOP</varname>, as defined by the
+ <ulink
+ url="http://standards.freedesktop.org/desktop-entry-spec/latest/">Desktop
+ Entry Specification</ulink>. (However, note that
+ <varname>$XDG_SESSION_DESKTOP</varname> only takes a single
+ item, and not a colon-separated list like
+ <varname>$XDG_CURRENT_DESKTOP</varname>.) See
+ <citerefentry><refentrytitle>sd_session_get_desktop</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ for more details.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>$XDG_SEAT</varname></term>
+
+ <listitem><para>The seat name the session shall be registered
+ for, if any.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>$XDG_VTNR</varname></term>
+
+ <listitem><para>The VT number the session shall be registered
+ for, if any. (Only applies to seats with a VT available, such
+ as <literal>seat0</literal>)</para></listitem>
+ </varlistentry>
+
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Example</title>
+
+ <programlisting>#%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</programlisting>
+ </refsect1>
+
+ <refsect1>
+ <title>See Also</title>
+ <para>
+ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>logind.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>pam.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>pam.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>pam_loginuid</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ </para>
+ </refsect1>
+
+</refentry>