X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fpam-module.c;h=dc7c00166e6ca35f1f313de3df236a9c57d93a9b;hp=bc99684e110702587dd6398995081047c2ee066e;hb=ed18b08bed983b845c72a83666a7d7db546d89ad;hpb=d90b9d27af56f808a275789c7aa228f6300175d7

diff --git a/src/pam-module.c b/src/pam-module.c
index bc99684e1..dc7c00166 100644
--- a/src/pam-module.c
+++ b/src/pam-module.c
@@ -24,6 +24,7 @@
 #include <sys/file.h>
 #include <pwd.h>
 #include <endian.h>
+#include <sys/capability.h>
 
 #include <security/pam_modules.h>
 #include <security/_pam_macros.h>
@@ -32,17 +33,24 @@
 #include <security/pam_misc.h>
 
 #include "util.h"
-#include "cgroup-util.h"
 #include "macro.h"
 #include "sd-daemon.h"
+#include "strv.h"
+#include "dbus-common.h"
+#include "def.h"
 
 static int parse_argv(pam_handle_t *handle,
                       int argc, const char **argv,
-                      bool *create_session,
-                      bool *kill_session,
-                      bool *kill_user) {
+                      char ***controllers,
+                      char ***reset_controllers,
+                      bool *kill_processes,
+                      char ***kill_only_users,
+                      char ***kill_exclude_users,
+                      bool *debug) {
 
         unsigned i;
+        bool reset_controller_set = false;
+        bool kill_exclude_users_set = false;
 
         assert(argc >= 0);
         assert(argc == 0 || argv);
@@ -50,130 +58,137 @@ static int parse_argv(pam_handle_t *handle,
         for (i = 0; i < (unsigned) argc; i++) {
                 int k;
 
-                if (startswith(argv[i], "create-session=")) {
+                if (startswith(argv[i], "kill-processes=")) {
                         if ((k = parse_boolean(argv[i] + 15)) < 0) {
-                                pam_syslog(handle, LOG_ERR, "Failed to parse create-session= argument.");
+                                pam_syslog(handle, LOG_ERR, "Failed to parse kill-processes= argument.");
                                 return k;
                         }
 
-                        if (create_session)
-                                *create_session = k;
+                        if (kill_processes)
+                                *kill_processes = k;
+
                 } else if (startswith(argv[i], "kill-session=")) {
+                        /* As compatibility for old versions */
+
                         if ((k = parse_boolean(argv[i] + 13)) < 0) {
                                 pam_syslog(handle, LOG_ERR, "Failed to parse kill-session= argument.");
                                 return k;
                         }
 
-                        if (kill_session)
-                                *kill_session = k;
+                        if (kill_processes)
+                                *kill_processes = k;
 
-                } else if (startswith(argv[i], "kill-user=")) {
-                        if ((k = parse_boolean(argv[i] + 10)) < 0) {
-                                pam_syslog(handle, LOG_ERR, "Failed to parse kill-user= argument.");
-                                return k;
+                } else if (startswith(argv[i], "controllers=")) {
+
+                        if (controllers) {
+                                char **l;
+
+                                if (!(l = strv_split(argv[i] + 12, ","))) {
+                                        pam_syslog(handle, LOG_ERR, "Out of memory.");
+                                        return -ENOMEM;
+                                }
+
+                                strv_free(*controllers);
+                                *controllers = l;
                         }
 
-                        if (kill_user)
-                                *kill_user = k;
-                } else {
-                        pam_syslog(handle, LOG_ERR, "Unknown parameter '%s'.", argv[i]);
-                        return -EINVAL;
-                }
-        }
+                } else if (startswith(argv[i], "reset-controllers=")) {
 
-        if (kill_session && *kill_session && kill_user)
-                *kill_user = true;
+                        if (reset_controllers) {
+                                char **l;
 
-        return 0;
-}
+                                if (!(l = strv_split(argv[i] + 18, ","))) {
+                                        pam_syslog(handle, LOG_ERR, "Out of memory.");
+                                        return -ENOMEM;
+                                }
 
-static int open_file_and_lock(const char *fn) {
-        int fd;
+                                strv_free(*reset_controllers);
+                                *reset_controllers = l;
+                        }
 
-        assert(fn);
+                        reset_controller_set = true;
 
-        if ((fd = open(fn, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_CREAT, 0600)) < 0)
-                return -errno;
+                } else if (startswith(argv[i], "kill-only-users=")) {
 
-        /* The BSD socket semantics are a lot nicer than those of
-         * POSIX locks. Which is why we use flock() here. BSD locking
-         * does not work across NFS which however is not needed here
-         * as the filesystems in question should be local, and only
-         * locally accessible, and most likely even tmpfs. */
+                        if (kill_only_users) {
+                                char **l;
 
-        if (flock(fd, LOCK_EX) < 0)
-                return -errno;
+                                if (!(l = strv_split(argv[i] + 16, ","))) {
+                                        pam_syslog(handle, LOG_ERR, "Out of memory.");
+                                        return -ENOMEM;
+                                }
 
-        return fd;
-}
+                                strv_free(*kill_only_users);
+                                *kill_only_users = l;
+                        }
 
-enum {
-        SESSION_ID_AUDIT = 'a',
-        SESSION_ID_COUNTER = 'c',
-        SESSION_ID_RANDOM = 'r'
-};
+                } else if (startswith(argv[i], "kill-exclude-users=")) {
 
-static uint64_t get_session_id(int *mode) {
-        char *s;
-        int fd;
+                        if (kill_exclude_users) {
+                                char **l;
 
-        assert(mode);
+                                if (!(l = strv_split(argv[i] + 19, ","))) {
+                                        pam_syslog(handle, LOG_ERR, "Out of memory.");
+                                        return -ENOMEM;
+                                }
 
-        /* First attempt: let's use the session ID of the audit
-         * system, if it is available. */
-        if (read_one_line_file("/proc/self/sessionid", &s) >= 0) {
-                uint32_t u;
-                int r;
+                                strv_free(*kill_exclude_users);
+                                *kill_exclude_users = l;
+                        }
 
-                r = safe_atou32(s, &u);
-                free(s);
+                        kill_exclude_users_set = true;
 
-                if (r >= 0 && u != (uint32_t) -1 && u > 0) {
-                        *mode = SESSION_ID_AUDIT;
-                        return (uint64_t) u;
+                } else if (startswith(argv[i], "debug=")) {
+                        if ((k = parse_boolean(argv[i] + 6)) < 0) {
+                                pam_syslog(handle, LOG_ERR, "Failed to parse debug= argument.");
+                                return k;
+                        }
+
+                        if (debug)
+                                *debug = k;
+
+                } else if (startswith(argv[i], "create-session=") ||
+                           startswith(argv[i], "kill-user=")) {
+
+                        pam_syslog(handle, LOG_WARNING, "Option %s not supported anymore, ignoring.", argv[i]);
+
+                } else {
+                        pam_syslog(handle, LOG_ERR, "Unknown parameter '%s'.", argv[i]);
+                        return -EINVAL;
                 }
         }
 
-        /* Second attempt, use our own counter. */
-        if ((fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-session")) >= 0) {
-                uint64_t counter;
-                ssize_t r;
+        if (!reset_controller_set && reset_controllers) {
+                char **l;
 
-                /* We do a bit of endianess swapping here, just to be
-                 * sure. /var should be machine specific anyway, and
-                 * /var/run even mounted from tmpfs, so this
-                 * byteswapping should really not be necessary. But
-                 * then again, you never know, so let's avoid any
-                 * risk. */
-
-                if (loop_read(fd, &counter, sizeof(counter), false) != sizeof(counter))
-                        counter = 1;
-                else
-                        counter = le64toh(counter) + 1;
+                if (!(l = strv_new("cpu", NULL))) {
+                        pam_syslog(handle, LOG_ERR, "Out of memory");
+                        return -ENOMEM;
+                }
 
-                if (lseek(fd, 0, SEEK_SET) == 0) {
-                        uint64_t swapped = htole64(counter);
+                *reset_controllers = l;
+        }
 
-                        r = loop_write(fd, &swapped, sizeof(swapped), false);
+        if (controllers)
+                strv_remove(*controllers, SYSTEMD_CGROUP_CONTROLLER);
 
-                        if (r != sizeof(swapped))
-                                r = -EIO;
-                } else
-                        r = -errno;
+        if (reset_controllers)
+                strv_remove(*reset_controllers, SYSTEMD_CGROUP_CONTROLLER);
 
-                close_nointr_nofail(fd);
+        if (!kill_exclude_users_set && kill_exclude_users) {
+                char **l;
 
-                if (r >= 0) {
-                        *mode = SESSION_ID_COUNTER;
-                        return counter;
+                if (!(l = strv_new("root", NULL))) {
+                        pam_syslog(handle, LOG_ERR, "Out of memory");
+                        return -ENOMEM;
                 }
-        }
 
-        *mode = SESSION_ID_RANDOM;
+                *kill_exclude_users = l;
+        }
 
-        /* Last attempt, pick a random value */
-        return (uint64_t) random_ull();
+        return 0;
 }
+
 static int get_user_data(
                 pam_handle_t *handle,
                 const char **ret_username,
@@ -189,15 +204,24 @@ static int get_user_data(
         assert(ret_username);
         assert(ret_pw);
 
-        if (read_one_line_file("/proc/self/loginuid", &s) >= 0) {
-                uint32_t u;
+        if (have_effective_cap(CAP_AUDIT_CONTROL) > 0) {
+                /* Only use audit login uid if we are executed with
+                 * sufficient capabilities so that pam_loginuid could
+                 * do its job. If we are lacking the CAP_AUDIT_CONTROL
+                 * capabality we most likely are being run in a
+                 * container and /proc/self/loginuid is useless since
+                 * it probably contains a uid of the host system. */
+
+                if (read_one_line_file("/proc/self/loginuid", &s) >= 0) {
+                        uint32_t u;
 
-                r = safe_atou32(s, &u);
-                free(s);
+                        r = safe_atou32(s, &u);
+                        free(s);
 
-                if (r >= 0 && u != (uint32_t) -1 && u > 0) {
-                        have_loginuid = true;
-                        pw = pam_modutil_getpwuid(handle, u);
+                        if (r >= 0 && u != (uint32_t) -1 && u > 0) {
+                                have_loginuid = true;
+                                pw = pam_modutil_getpwuid(handle, u);
+                        }
                 }
         }
 
@@ -226,40 +250,53 @@ static int get_user_data(
         return PAM_SUCCESS;
 }
 
-static int create_user_group(pam_handle_t *handle, const char *group, struct passwd *pw, bool attach, bool remember) {
-        int r;
+static bool check_user_lists(
+                pam_handle_t *handle,
+                uid_t uid,
+                char **kill_only_users,
+                char **kill_exclude_users) {
+
+        const char *name = NULL;
+        char **l;
 
         assert(handle);
-        assert(group);
 
-        if (attach)
-                r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, group, 0);
-        else
-                r = cg_create(SYSTEMD_CGROUP_CONTROLLER, group);
+        if (uid == 0)
+                name = "root"; /* Avoid obvious NSS requests, to suppress network traffic */
+        else {
+                struct passwd *pw;
 
-        if (r < 0) {
-                pam_syslog(handle, LOG_ERR, "Failed to create cgroup: %s", strerror(-r));
-                return PAM_SESSION_ERR;
+                pw = pam_modutil_getpwuid(handle, uid);
+                if (pw)
+                        name = pw->pw_name;
         }
 
-        if (r > 0 && remember) {
-                /* Remember that it was us who created this group, and
-                 * that hence we need to remove it too. This is a
-                 * protection against removing the cgroup when run
-                 * recursively. */
-                if ((r = pam_set_data(handle, "systemd.created", INT_TO_PTR(1), NULL)) != PAM_SUCCESS) {
-                        pam_syslog(handle, LOG_ERR, "Failed to install created variable.");
-                        return r;
-                }
+        STRV_FOREACH(l, kill_exclude_users) {
+                uint32_t id;
+
+                if (safe_atou32(*l, &id) >= 0)
+                        if ((uid_t) id == uid)
+                                return false;
+
+                if (name && streq(name, *l))
+                        return false;
         }
 
-        if ((r = cg_set_task_access(SYSTEMD_CGROUP_CONTROLLER, group, 0755, pw->pw_uid, pw->pw_gid)) < 0 ||
-            (r = cg_set_group_access(SYSTEMD_CGROUP_CONTROLLER, group, 0755, pw->pw_uid, pw->pw_gid)) < 0) {
-                pam_syslog(handle, LOG_ERR, "Failed to change access modes: %s", strerror(-r));
-                return PAM_SESSION_ERR;
+        if (strv_isempty(kill_only_users))
+                return true;
+
+        STRV_FOREACH(l, kill_only_users) {
+                uint32_t id;
+
+                if (safe_atou32(*l, &id) >= 0)
+                        if ((uid_t) id == uid)
+                                return true;
+
+                if (name && streq(name, *l))
+                        return true;
         }
 
-        return PAM_SUCCESS;
+        return false;
 }
 
 _public_ PAM_EXTERN int pam_sm_open_session(
@@ -267,258 +304,205 @@ _public_ PAM_EXTERN int pam_sm_open_session(
                 int flags,
                 int argc, const char **argv) {
 
-        const char *username = NULL;
         struct passwd *pw;
+        bool kill_processes = false, debug = false;
+        const char *username, *id, *object_path, *runtime_path, *service = NULL, *tty = NULL, *display = NULL, *remote_user = NULL, *remote_host = NULL, *seat = NULL, *type;
+        char **controllers = NULL, **reset_controllers = NULL, **kill_only_users = NULL, **kill_exclude_users = NULL;
+        DBusError error;
+        uint32_t uid, pid;
+        DBusMessageIter iter;
+        dbus_bool_t kp;
+        int session_fd = -1;
+        DBusConnection *bus = NULL;
+        DBusMessage *m = NULL, *reply = NULL;
+        dbus_bool_t remote;
         int r;
-        char *buf = NULL;
-        int lock_fd = -1;
-        bool create_session = true;
 
         assert(handle);
 
-        /* pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing"); */
+        dbus_error_init(&error);
 
-        if (parse_argv(handle, argc, argv, &create_session, NULL, NULL) < 0)
-                return PAM_SESSION_ERR;
+        /* pam_syslog(handle, LOG_INFO, "pam-systemd initializing"); */
 
         /* Make this a NOP on non-systemd systems */
         if (sd_booted() <= 0)
                 return PAM_SUCCESS;
 
-        if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
+        if (parse_argv(handle,
+                       argc, argv,
+                       &controllers, &reset_controllers,
+                       &kill_processes, &kill_only_users, &kill_exclude_users,
+                       &debug) < 0) {
+                r = PAM_SESSION_ERR;
                 goto finish;
+        }
 
-        if (safe_mkdir(RUNTIME_DIR "/user", 0755, 0, 0) < 0) {
-                pam_syslog(handle, LOG_ERR, "Failed to create runtime directory: %m");
-                r = PAM_SYSTEM_ERR;
+        r = get_user_data(handle, &username, &pw);
+        if (r != PAM_SUCCESS)
                 goto finish;
-        }
 
-        if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
-                pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
-                r = PAM_SYSTEM_ERR;
+        if (kill_processes)
+                kill_processes = check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users);
+
+        dbus_connection_set_change_sigpipe(FALSE);
+
+        bus = dbus_bus_get_private(DBUS_BUS_SYSTEM, &error);
+        if (!bus) {
+                pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", bus_error_message(&error));
+                r = PAM_SESSION_ERR;
                 goto finish;
         }
 
-        /* Create /var/run/$USER */
-        free(buf);
-        if (asprintf(&buf, RUNTIME_DIR "/user/%s", username) < 0) {
+        m = dbus_message_new_method_call(
+                        "org.freedesktop.login1",
+                        "/org/freedesktop/login1",
+                        "org.freedesktop.login1.Manager",
+                        "CreateSession");
+
+        if (!m) {
+                pam_syslog(handle, LOG_ERR, "Could not allocate create session message.");
                 r = PAM_BUF_ERR;
                 goto finish;
         }
 
-        if (safe_mkdir(buf, 0700, pw->pw_uid, pw->pw_gid) < 0) {
-                pam_syslog(handle, LOG_WARNING, "Failed to create runtime directory: %m");
-                r = PAM_SYSTEM_ERR;
-                goto finish;
-        } else if ((r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", buf, 0)) != PAM_SUCCESS) {
-                pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
+        uid = pw->pw_uid;
+        pid = getpid();
+
+        pam_get_item(handle, PAM_SERVICE, (const void**) &service);
+        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");
+
+        service = strempty(service);
+        tty = strempty(tty);
+        display = strempty(display);
+        remote_user = strempty(remote_user);
+        remote_host = strempty(remote_host);
+        seat = strempty(seat);
+
+        type = !isempty(display) ? "x11" :
+                   !isempty(tty) ? "tty" : "other";
+
+        remote = !isempty(remote_host) && !streq(remote_host, "localhost") && !streq(remote_host, "localhost.localdomain");
+
+        if (!dbus_message_append_args(m,
+                                      DBUS_TYPE_UINT32, &uid,
+                                      DBUS_TYPE_UINT32, &pid,
+                                      DBUS_TYPE_STRING, &service,
+                                      DBUS_TYPE_STRING, &type,
+                                      DBUS_TYPE_STRING, &seat,
+                                      DBUS_TYPE_STRING, &tty,
+                                      DBUS_TYPE_STRING, &display,
+                                      DBUS_TYPE_BOOLEAN, &remote,
+                                      DBUS_TYPE_STRING, &remote_user,
+                                      DBUS_TYPE_STRING, &remote_host,
+                                      DBUS_TYPE_INVALID)) {
+                pam_syslog(handle, LOG_ERR, "Could not attach parameters to message.");
+                r = PAM_BUF_ERR;
                 goto finish;
         }
 
-        free(buf);
-        buf = NULL;
-
-        if (create_session) {
-                const char *id;
-
-                /* Reuse or create XDG session ID */
-                if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
-                        int mode;
-
-                        if (asprintf(&buf, "%llux", (unsigned long long) get_session_id(&mode)) < 0) {
-                                r = PAM_BUF_ERR;
-                                goto finish;
-                        }
-
-                        /* To avoid id clashes we add the session id
-                         * source to our session ids. Note that the
-                         * session id source might change during
-                         * runtime, because a filesystem became
-                         * writable or the system reconfigured. */
-                        buf[strlen(buf)-1] =
-                                mode != SESSION_ID_AUDIT ? (char) mode : 0;
-
-                        if ((r = pam_misc_setenv(handle, "XDG_SESSION_ID", buf, 0)) != PAM_SUCCESS) {
-                                pam_syslog(handle, LOG_ERR, "Failed to set session id.");
-                                goto finish;
-                        }
-
-                        if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
-                                pam_syslog(handle, LOG_ERR, "Failed to get session id.");
-                                r = PAM_SESSION_ERR;
-                                goto finish;
-                        }
-                }
-
-                r = asprintf(&buf, "/user/%s/%s", username, id);
-        } else
-                r = asprintf(&buf, "/user/%s/master", username);
+        dbus_message_iter_init_append(m, &iter);
 
+        r = bus_append_strv_iter(&iter, controllers);
         if (r < 0) {
+                pam_syslog(handle, LOG_ERR, "Could not attach parameter to message.");
                 r = PAM_BUF_ERR;
                 goto finish;
         }
 
-        pam_syslog(handle, LOG_INFO, "Moving new user session for %s into control group %s.", username, buf);
-
-        if ((r = create_user_group(handle, buf, pw, true, true)) != PAM_SUCCESS)
+        r = bus_append_strv_iter(&iter, reset_controllers);
+        if (r < 0) {
+                pam_syslog(handle, LOG_ERR, "Could not attach parameter to message.");
+                r = PAM_BUF_ERR;
                 goto finish;
-
-        r = PAM_SUCCESS;
-
-finish:
-        free(buf);
-
-        if (lock_fd >= 0)
-                close_nointr_nofail(lock_fd);
-
-        return r;
-}
-
-static int session_remains(pam_handle_t *handle, const char *user_path) {
-        int r;
-        bool remains = false;
-        DIR *d;
-        char *subgroup;
-
-        if ((r = cg_enumerate_subgroups(SYSTEMD_CGROUP_CONTROLLER, user_path, &d)) < 0)
-                return r;
-
-        while ((r = cg_read_subgroup(d, &subgroup)) > 0) {
-
-                remains = !streq(subgroup, "master");
-                free(subgroup);
-
-                if (remains)
-                        break;
         }
 
-        closedir(d);
-
-        if (r < 0)
-                return r;
-
-        return !!remains;
-}
-
-_public_ PAM_EXTERN int pam_sm_close_session(
-                pam_handle_t *handle,
-                int flags,
-                int argc, const char **argv) {
-
-        const char *username = NULL;
-        bool kill_session = false;
-        bool kill_user = false;
-        int lock_fd = -1, r;
-        char *session_path = NULL, *nosession_path = NULL, *user_path = NULL;
-        const char *id;
-        struct passwd *pw;
-        const void *created = NULL;
-
-        assert(handle);
-
-        if (parse_argv(handle, argc, argv, NULL, &kill_session, &kill_user) < 0)
-                return PAM_SESSION_ERR;
-
-        /* Make this a NOP on non-systemd systems */
-        if (sd_booted() <= 0)
-                return PAM_SUCCESS;
-
-        if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
+        kp = kill_processes;
+        if (!dbus_message_iter_append_basic(&iter, DBUS_TYPE_BOOLEAN, &kp)) {
+                pam_syslog(handle, LOG_ERR, "Could not attach parameter to message.");
+                r = PAM_BUF_ERR;
                 goto finish;
+        }
 
-        if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
-                pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
-                r = PAM_SYSTEM_ERR;
+        reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error);
+        if (!reply) {
+                pam_syslog(handle, LOG_ERR, "Failed to create session: %s", bus_error_message(&error));
+                r = PAM_SESSION_ERR;
                 goto finish;
         }
 
-        /* We are probably still in some session/user dir. Move ourselves out of the way as first step */
-        if ((r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, "/user", 0)) < 0)
-                pam_syslog(handle, LOG_ERR, "Failed to move us away: %s", strerror(-r));
-
-        if (asprintf(&user_path, "/user/%s", username) < 0) {
-                r = PAM_BUF_ERR;
+        if (!dbus_message_get_args(reply, &error,
+                                   DBUS_TYPE_STRING, &id,
+                                   DBUS_TYPE_OBJECT_PATH, &object_path,
+                                   DBUS_TYPE_STRING, &runtime_path,
+                                   DBUS_TYPE_UNIX_FD, &session_fd,
+                                   DBUS_TYPE_INVALID)) {
+                pam_syslog(handle, LOG_ERR, "Failed to parse message: %s", bus_error_message(&error));
+                r = PAM_SESSION_ERR;
                 goto finish;
         }
 
-        pam_get_data(handle, "systemd.created", &created);
-
-        if ((id = pam_getenv(handle, "XDG_SESSION_ID")) && created) {
-
-                if (asprintf(&session_path, "/user/%s/%s", username, id) < 0 ||
-                    asprintf(&nosession_path, "/user/%s/master", username) < 0) {
-                        r = PAM_BUF_ERR;
-                        goto finish;
-                }
-
-                if (kill_session)  {
-                        pam_syslog(handle, LOG_INFO, "Killing remaining processes of user session %s of %s.", id, username);
-
-                        /* Kill processes in session cgroup, and delete it */
-                        if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, session_path, true)) < 0)
-                                pam_syslog(handle, LOG_ERR, "Failed to kill session cgroup: %s", strerror(-r));
-                } else {
-                        pam_syslog(handle, LOG_INFO, "Moving remaining processes of user session %s of %s into control group %s.", id, username, nosession_path);
+        r = pam_misc_setenv(handle, "XDG_SESSION_ID", id, 0);
+        if (r != PAM_SUCCESS) {
+                pam_syslog(handle, LOG_ERR, "Failed to set session id.");
+                goto finish;
+        }
 
-                        /* Migrate processes from session to user
-                         * cgroup. First, try to create the user group
-                         * in case it doesn't exist yet. Also, delete
-                         * the session group. */
-                        create_user_group(handle, nosession_path, pw, false, false);
+        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.");
+                goto finish;
+        }
 
-                        if ((r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, session_path, nosession_path, false, true)) < 0)
-                                pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup: %s", strerror(-r));
-                }
+        r = pam_set_data(handle, "systemd.session-fd", INT_TO_PTR(session_fd+1), NULL);
+        if (r != PAM_SUCCESS) {
+                pam_syslog(handle, LOG_ERR, "Failed to install session fd.");
+                return r;
         }
 
-        /* GC user tree */
-        cg_trim(SYSTEMD_CGROUP_CONTROLLER, user_path, false);
+        session_fd = -1;
 
-        if ((r = session_remains(handle, user_path)) < 0)
-                pam_syslog(handle, LOG_ERR, "Failed to determine whether a session remains: %s", strerror(-r));
+        r = PAM_SUCCESS;
 
-        /* Kill user processes not attached to any session */
-        if (kill_user && r == 0) {
+finish:
+        strv_free(controllers);
+        strv_free(reset_controllers);
+        strv_free(kill_only_users);
+        strv_free(kill_exclude_users);
 
-                /* Kill user cgroup */
-                if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
-                        pam_syslog(handle, LOG_ERR, "Failed to kill user cgroup: %s", strerror(-r));
-        } else {
+        dbus_error_free(&error);
 
-                if ((r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
-                        pam_syslog(handle, LOG_ERR, "Failed to check user cgroup: %s", strerror(-r));
+        if (bus) {
+                dbus_connection_close(bus);
+                dbus_connection_unref(bus);
+        }
 
-                /* Remove user cgroup */
-                if (r > 0) {
-                        if ((r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, user_path)) < 0)
-                                pam_syslog(handle, LOG_ERR, "Failed to delete user cgroup: %s", strerror(-r));
+        if (m)
+                dbus_message_unref(m);
 
-                /* If we managed to find somebody, don't cleanup the cgroup. */
-                } else if (r == 0)
-                        r = -EBUSY;
-        }
+        if (reply)
+                dbus_message_unref(reply);
 
-        if (r >= 0) {
-                const char *runtime_dir;
+        if (session_fd >= 0)
+                close_nointr_nofail(session_fd);
 
-                if ((runtime_dir = pam_getenv(handle, "XDG_RUNTIME_DIR")))
-                        if ((r = rm_rf(runtime_dir, false, true)) < 0)
-                                pam_syslog(handle, LOG_ERR, "Failed to remove runtime directory: %s", strerror(-r));
-        }
+        return r;
+}
 
-        /* pam_syslog(handle, LOG_DEBUG, "pam-systemd done"); */
+_public_ PAM_EXTERN int pam_sm_close_session(
+                pam_handle_t *handle,
+                int flags,
+                int argc, const char **argv) {
 
-        r = PAM_SUCCESS;
+        const void *p = NULL;
 
-finish:
-        if (lock_fd >= 0)
-                close_nointr_nofail(lock_fd);
+        pam_get_data(handle, "systemd.session-fd", &p);
 
-        free(session_path);
-        free(nosession_path);
-        free(user_path);
+        if (p)
+                close_nointr(PTR_TO_INT(p) - 1);
 
-        return r;
+        return PAM_SUCCESS;
 }