1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2010 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
28 #include <security/pam_modules.h>
29 #include <security/_pam_macros.h>
30 #include <security/pam_modutil.h>
31 #include <security/pam_ext.h>
32 #include <security/pam_misc.h>
35 #include "cgroup-util.h"
37 #include "sd-daemon.h"
40 static int parse_argv(pam_handle_t *handle,
41 int argc, const char **argv,
46 char ***reset_controllers,
47 char ***kill_only_users,
48 char ***kill_exclude_users) {
51 bool reset_controller_set = false;
52 bool kill_exclude_users_set = false;
55 assert(argc == 0 || argv);
57 for (i = 0; i < (unsigned) argc; i++) {
60 if (startswith(argv[i], "create-session=")) {
61 if ((k = parse_boolean(argv[i] + 15)) < 0) {
62 pam_syslog(handle, LOG_ERR, "Failed to parse create-session= argument.");
69 } else if (startswith(argv[i], "kill-session=")) {
70 if ((k = parse_boolean(argv[i] + 13)) < 0) {
71 pam_syslog(handle, LOG_ERR, "Failed to parse kill-session= argument.");
78 } else if (startswith(argv[i], "kill-user=")) {
79 if ((k = parse_boolean(argv[i] + 10)) < 0) {
80 pam_syslog(handle, LOG_ERR, "Failed to parse kill-user= argument.");
87 } else if (startswith(argv[i], "controllers=")) {
92 if (!(l = strv_split(argv[i] + 12, ","))) {
93 pam_syslog(handle, LOG_ERR, "Out of memory.");
97 strv_free(*controllers);
101 } else if (startswith(argv[i], "reset-controllers=")) {
103 if (reset_controllers) {
106 if (!(l = strv_split(argv[i] + 18, ","))) {
107 pam_syslog(handle, LOG_ERR, "Out of memory.");
111 strv_free(*reset_controllers);
112 *reset_controllers = l;
115 reset_controller_set = true;
117 } else if (startswith(argv[i], "kill-only-users=")) {
119 if (kill_only_users) {
122 if (!(l = strv_split(argv[i] + 16, ","))) {
123 pam_syslog(handle, LOG_ERR, "Out of memory.");
127 strv_free(*kill_only_users);
128 *kill_only_users = l;
131 } else if (startswith(argv[i], "kill-exclude-users=")) {
133 if (kill_exclude_users) {
136 if (!(l = strv_split(argv[i] + 19, ","))) {
137 pam_syslog(handle, LOG_ERR, "Out of memory.");
141 strv_free(*kill_exclude_users);
142 *kill_exclude_users = l;
145 kill_exclude_users_set = true;
148 pam_syslog(handle, LOG_ERR, "Unknown parameter '%s'.", argv[i]);
153 if (!reset_controller_set && reset_controllers) {
156 if (!(l = strv_new("cpu", NULL))) {
157 pam_syslog(handle, LOG_ERR, "Out of memory");
161 *reset_controllers = l;
165 strv_remove(*controllers, "name=systemd");
167 if (reset_controllers)
168 strv_remove(*reset_controllers, "name=systemd");
170 if (kill_session && *kill_session && kill_user)
173 if (!kill_exclude_users_set && kill_exclude_users) {
176 if (!(l = strv_new("root", NULL))) {
177 pam_syslog(handle, LOG_ERR, "Out of memory");
181 *kill_exclude_users = l;
187 static int open_file_and_lock(const char *fn) {
192 if ((fd = open(fn, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_CREAT, 0600)) < 0)
195 /* The BSD socket semantics are a lot nicer than those of
196 * POSIX locks. Which is why we use flock() here. BSD locking
197 * does not work across NFS which however is not needed here
198 * as the filesystems in question should be local, and only
199 * locally accessible, and most likely even tmpfs. */
201 if (flock(fd, LOCK_EX) < 0) {
202 close_nointr_nofail(fd);
210 SESSION_ID_AUDIT = 'a',
211 SESSION_ID_COUNTER = 'c',
212 SESSION_ID_RANDOM = 'r'
215 static uint64_t get_session_id(int *mode) {
221 /* First attempt: let's use the session ID of the audit
222 * system, if it is available. */
223 if (read_one_line_file("/proc/self/sessionid", &s) >= 0) {
227 r = safe_atou32(s, &u);
230 if (r >= 0 && u != (uint32_t) -1 && u > 0) {
231 *mode = SESSION_ID_AUDIT;
236 /* Second attempt, use our own counter. */
237 if ((fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-session")) >= 0) {
241 /* We do a bit of endianess swapping here, just to be
242 * sure. /var should be machine specific anyway, and
243 * /var/run even mounted from tmpfs, so this
244 * byteswapping should really not be necessary. But
245 * then again, you never know, so let's avoid any
248 if (loop_read(fd, &counter, sizeof(counter), false) != sizeof(counter))
251 counter = le64toh(counter) + 1;
253 if (lseek(fd, 0, SEEK_SET) == 0) {
254 uint64_t swapped = htole64(counter);
256 r = loop_write(fd, &swapped, sizeof(swapped), false);
258 if (r != sizeof(swapped))
263 close_nointr_nofail(fd);
266 *mode = SESSION_ID_COUNTER;
271 *mode = SESSION_ID_RANDOM;
273 /* Last attempt, pick a random value */
274 return (uint64_t) random_ull();
277 static int get_user_data(
278 pam_handle_t *handle,
279 const char **ret_username,
280 struct passwd **ret_pw) {
282 const char *username = NULL;
283 struct passwd *pw = NULL;
285 bool have_loginuid = false;
289 assert(ret_username);
292 if (read_one_line_file("/proc/self/loginuid", &s) >= 0) {
295 r = safe_atou32(s, &u);
298 if (r >= 0 && u != (uint32_t) -1 && u > 0) {
299 have_loginuid = true;
300 pw = pam_modutil_getpwuid(handle, u);
304 if (!have_loginuid) {
305 if ((r = pam_get_user(handle, &username, NULL)) != PAM_SUCCESS) {
306 pam_syslog(handle, LOG_ERR, "Failed to get user name.");
310 if (!username || !*username) {
311 pam_syslog(handle, LOG_ERR, "User name not valid.");
315 pw = pam_modutil_getpwnam(handle, username);
319 pam_syslog(handle, LOG_ERR, "Failed to get user data.");
320 return PAM_USER_UNKNOWN;
324 *ret_username = username ? username : pw->pw_name;
329 static int create_user_group(
330 pam_handle_t *handle,
331 const char *controller,
343 r = cg_create_and_attach(controller, group, 0);
345 r = cg_create(controller, group);
348 pam_syslog(handle, LOG_ERR, "Failed to create cgroup: %s", strerror(-r));
349 return PAM_SESSION_ERR;
352 if (r > 0 && remember) {
353 /* Remember that it was us who created this group, and
354 * that hence we need to remove it too. This is a
355 * protection against removing the cgroup when run
357 if ((r = pam_set_data(handle, "systemd.created", INT_TO_PTR(1), NULL)) != PAM_SUCCESS) {
358 pam_syslog(handle, LOG_ERR, "Failed to install created variable.");
363 if ((r = cg_set_task_access(controller, group, 0644, pw->pw_uid, pw->pw_gid)) < 0 ||
364 (r = cg_set_group_access(controller, group, 0755, pw->pw_uid, pw->pw_gid)) < 0) {
365 pam_syslog(handle, LOG_ERR, "Failed to change access modes: %s", strerror(-r));
366 return PAM_SESSION_ERR;
372 static int reset_group(
373 pam_handle_t *handle,
374 const char *controller) {
380 if ((r = cg_attach(controller, "/", 0)) < 0) {
381 pam_syslog(handle, LOG_ERR, "Failed to reset cgroup for controller %s: %s", controller, strerror(-r));
382 return PAM_SESSION_ERR;
388 _public_ PAM_EXTERN int pam_sm_open_session(
389 pam_handle_t *handle,
391 int argc, const char **argv) {
393 const char *username = NULL;
398 bool create_session = true;
399 char **controllers = NULL, **reset_controllers = NULL, **c;
400 char *cgroup_user_tree = NULL;
404 /* pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing"); */
406 /* Make this a NOP on non-systemd systems */
407 if (sd_booted() <= 0)
410 if (parse_argv(handle,
412 &create_session, NULL, NULL,
413 &controllers, &reset_controllers,
415 return PAM_SESSION_ERR;
417 if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
420 if ((r = cg_get_user_path(&cgroup_user_tree)) < 0) {
421 pam_syslog(handle, LOG_ERR, "Failed to determine user cgroup tree: %s", strerror(-r));
426 if (safe_mkdir(RUNTIME_DIR "/user", 0755, 0, 0) < 0) {
427 pam_syslog(handle, LOG_ERR, "Failed to create runtime directory: %m");
432 if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
433 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
438 /* Create /var/run/$USER */
440 if (asprintf(&buf, RUNTIME_DIR "/user/%s", username) < 0) {
445 if (safe_mkdir(buf, 0700, pw->pw_uid, pw->pw_gid) < 0) {
446 pam_syslog(handle, LOG_WARNING, "Failed to create runtime directory: %m");
449 } else if ((r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", buf, 0)) != PAM_SUCCESS) {
450 pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
457 if (create_session) {
460 /* Reuse or create XDG session ID */
461 if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
464 if (asprintf(&buf, "%llux", (unsigned long long) get_session_id(&mode)) < 0) {
469 /* To avoid id clashes we add the session id
470 * source to our session ids. Note that the
471 * session id source might change during
472 * runtime, because a filesystem became
473 * writable or the system reconfigured. */
475 mode != SESSION_ID_AUDIT ? (char) mode : 0;
477 if ((r = pam_misc_setenv(handle, "XDG_SESSION_ID", buf, 0)) != PAM_SUCCESS) {
478 pam_syslog(handle, LOG_ERR, "Failed to set session id.");
482 if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
483 pam_syslog(handle, LOG_ERR, "Failed to get session id.");
489 r = asprintf(&buf, "%s/%s/%s", cgroup_user_tree, username, id);
491 r = asprintf(&buf, "%s/%s/master", cgroup_user_tree, username);
498 pam_syslog(handle, LOG_INFO, "Moving new user session for %s into control group %s.", username, buf);
500 if ((r = create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, buf, pw, true, true)) != PAM_SUCCESS)
503 /* The additional controllers don't really matter, so we
504 * ignore the return value */
505 STRV_FOREACH(c, controllers)
506 create_user_group(handle, *c, buf, pw, true, false);
508 STRV_FOREACH(c, reset_controllers)
509 reset_group(handle, *c);
517 close_nointr_nofail(lock_fd);
519 strv_free(controllers);
520 strv_free(reset_controllers);
522 free(cgroup_user_tree);
527 static int session_remains(pam_handle_t *handle, const char *user_path) {
529 bool remains = false;
533 if ((r = cg_enumerate_subgroups(SYSTEMD_CGROUP_CONTROLLER, user_path, &d)) < 0)
536 while ((r = cg_read_subgroup(d, &subgroup)) > 0) {
538 remains = !streq(subgroup, "master");
553 static bool check_user_lists(
554 pam_handle_t *handle,
556 char **kill_only_users,
557 char **kill_exclude_users) {
559 const char *name = NULL;
565 name = "root"; /* Avoid obvious NSS requests, to suppress network traffic */
569 if ((pw = pam_modutil_getpwuid(handle, uid)))
573 STRV_FOREACH(l, kill_exclude_users) {
576 if (safe_atou32(*l, &id) >= 0)
577 if ((uid_t) id == uid)
580 if (name && streq(name, *l))
584 if (strv_isempty(kill_only_users))
587 STRV_FOREACH(l, kill_only_users) {
590 if (safe_atou32(*l, &id) >= 0)
591 if ((uid_t) id == uid)
594 if (name && streq(name, *l))
601 _public_ PAM_EXTERN int pam_sm_close_session(
602 pam_handle_t *handle,
604 int argc, const char **argv) {
606 const char *username = NULL;
607 bool kill_session = false;
608 bool kill_user = false;
610 char *session_path = NULL, *nosession_path = NULL, *user_path = NULL;
613 const void *created = NULL;
614 char **controllers = NULL, **c, **kill_only_users = NULL, **kill_exclude_users = NULL;
615 char *cgroup_user_tree = NULL;
619 /* Make this a NOP on non-systemd systems */
620 if (sd_booted() <= 0)
623 if (parse_argv(handle,
625 NULL, &kill_session, &kill_user,
627 &kill_only_users, &kill_exclude_users) < 0)
628 return PAM_SESSION_ERR;
630 if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
633 if ((r = cg_get_user_path(&cgroup_user_tree)) < 0) {
634 pam_syslog(handle, LOG_ERR, "Failed to determine user cgroup tree: %s", strerror(-r));
639 if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
640 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
645 /* We are probably still in some session/user dir. Move ourselves out of the way as first step */
646 if ((r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, cgroup_user_tree, 0)) < 0)
647 pam_syslog(handle, LOG_ERR, "Failed to move us away: %s", strerror(-r));
649 STRV_FOREACH(c, controllers)
650 if ((r = cg_attach(*c, cgroup_user_tree, 0)) < 0)
651 pam_syslog(handle, LOG_ERR, "Failed to move us away in %s hierarchy: %s", *c, strerror(-r));
653 if (asprintf(&user_path, "%s/%s", cgroup_user_tree, username) < 0) {
658 pam_get_data(handle, "systemd.created", &created);
660 if ((id = pam_getenv(handle, "XDG_SESSION_ID")) && created) {
662 if (asprintf(&session_path, "%s/%s/%s", cgroup_user_tree, username, id) < 0 ||
663 asprintf(&nosession_path, "%s/%s/master", cgroup_user_tree, username) < 0) {
668 if (kill_session && check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users)) {
669 pam_syslog(handle, LOG_INFO, "Killing remaining processes of user session %s of %s.", id, username);
671 /* Kill processes in session cgroup, and delete it */
672 if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, session_path, true)) < 0)
673 pam_syslog(handle, LOG_ERR, "Failed to kill session cgroup: %s", strerror(-r));
675 pam_syslog(handle, LOG_INFO, "Moving remaining processes of user session %s of %s into control group %s.", id, username, nosession_path);
677 /* Migrate processes from session to user
678 * cgroup. First, try to create the user group
679 * in case it doesn't exist yet. Also, delete
680 * the session group. */
681 create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, nosession_path, pw, false, false);
683 if ((r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, session_path, nosession_path, false, true)) < 0)
684 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup: %s", strerror(-r));
687 STRV_FOREACH(c, controllers) {
688 create_user_group(handle, *c, nosession_path, pw, false, false);
690 if ((r = cg_migrate_recursive(*c, session_path, nosession_path, false, true)) < 0)
691 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup in hierarchy %s: %s", *c, strerror(-r));
696 cg_trim(SYSTEMD_CGROUP_CONTROLLER, user_path, false);
698 if ((r = session_remains(handle, user_path)) < 0)
699 pam_syslog(handle, LOG_ERR, "Failed to determine whether a session remains: %s", strerror(-r));
701 /* Kill user processes not attached to any session */
702 if (kill_user && r == 0 && check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users)) {
704 /* Kill user cgroup */
705 if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
706 pam_syslog(handle, LOG_ERR, "Failed to kill user cgroup: %s", strerror(-r));
709 if ((r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
710 pam_syslog(handle, LOG_ERR, "Failed to check user cgroup: %s", strerror(-r));
712 /* Remove user cgroup */
714 if ((r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, user_path)) < 0)
715 pam_syslog(handle, LOG_ERR, "Failed to delete user cgroup: %s", strerror(-r));
717 /* If we managed to find somebody, don't cleanup the cgroup. */
722 STRV_FOREACH(c, controllers)
723 cg_trim(*c, user_path, true);
726 const char *runtime_dir;
728 if ((runtime_dir = pam_getenv(handle, "XDG_RUNTIME_DIR")))
729 if ((r = rm_rf(runtime_dir, false, true)) < 0)
730 pam_syslog(handle, LOG_ERR, "Failed to remove runtime directory: %s", strerror(-r));
733 /* pam_syslog(handle, LOG_DEBUG, "pam-systemd done"); */
739 close_nointr_nofail(lock_fd);
742 free(nosession_path);
745 strv_free(controllers);
746 strv_free(kill_exclude_users);
747 strv_free(kill_only_users);
749 free(cgroup_user_tree);