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/>.
27 #include <sys/capability.h>
29 #include <security/pam_modules.h>
30 #include <security/_pam_macros.h>
31 #include <security/pam_modutil.h>
32 #include <security/pam_ext.h>
33 #include <security/pam_misc.h>
36 #include "cgroup-util.h"
38 #include "sd-daemon.h"
41 static int parse_argv(pam_handle_t *handle,
42 int argc, const char **argv,
47 char ***reset_controllers,
48 char ***kill_only_users,
49 char ***kill_exclude_users) {
52 bool reset_controller_set = false;
53 bool kill_exclude_users_set = false;
56 assert(argc == 0 || argv);
58 for (i = 0; i < (unsigned) argc; i++) {
61 if (startswith(argv[i], "create-session=")) {
62 if ((k = parse_boolean(argv[i] + 15)) < 0) {
63 pam_syslog(handle, LOG_ERR, "Failed to parse create-session= argument.");
70 } else if (startswith(argv[i], "kill-session=")) {
71 if ((k = parse_boolean(argv[i] + 13)) < 0) {
72 pam_syslog(handle, LOG_ERR, "Failed to parse kill-session= argument.");
79 } else if (startswith(argv[i], "kill-user=")) {
80 if ((k = parse_boolean(argv[i] + 10)) < 0) {
81 pam_syslog(handle, LOG_ERR, "Failed to parse kill-user= argument.");
88 } else if (startswith(argv[i], "controllers=")) {
93 if (!(l = strv_split(argv[i] + 12, ","))) {
94 pam_syslog(handle, LOG_ERR, "Out of memory.");
98 strv_free(*controllers);
102 } else if (startswith(argv[i], "reset-controllers=")) {
104 if (reset_controllers) {
107 if (!(l = strv_split(argv[i] + 18, ","))) {
108 pam_syslog(handle, LOG_ERR, "Out of memory.");
112 strv_free(*reset_controllers);
113 *reset_controllers = l;
116 reset_controller_set = true;
118 } else if (startswith(argv[i], "kill-only-users=")) {
120 if (kill_only_users) {
123 if (!(l = strv_split(argv[i] + 16, ","))) {
124 pam_syslog(handle, LOG_ERR, "Out of memory.");
128 strv_free(*kill_only_users);
129 *kill_only_users = l;
132 } else if (startswith(argv[i], "kill-exclude-users=")) {
134 if (kill_exclude_users) {
137 if (!(l = strv_split(argv[i] + 19, ","))) {
138 pam_syslog(handle, LOG_ERR, "Out of memory.");
142 strv_free(*kill_exclude_users);
143 *kill_exclude_users = l;
146 kill_exclude_users_set = true;
149 pam_syslog(handle, LOG_ERR, "Unknown parameter '%s'.", argv[i]);
154 if (!reset_controller_set && reset_controllers) {
157 if (!(l = strv_new("cpu", NULL))) {
158 pam_syslog(handle, LOG_ERR, "Out of memory");
162 *reset_controllers = l;
166 strv_remove(*controllers, "name=systemd");
168 if (reset_controllers)
169 strv_remove(*reset_controllers, "name=systemd");
171 if (kill_session && *kill_session && kill_user)
174 if (!kill_exclude_users_set && kill_exclude_users) {
177 if (!(l = strv_new("root", NULL))) {
178 pam_syslog(handle, LOG_ERR, "Out of memory");
182 *kill_exclude_users = l;
188 static int open_file_and_lock(const char *fn) {
193 if ((fd = open(fn, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_CREAT, 0600)) < 0)
196 /* The BSD socket semantics are a lot nicer than those of
197 * POSIX locks. Which is why we use flock() here. BSD locking
198 * does not work across NFS which however is not needed here
199 * as the filesystems in question should be local, and only
200 * locally accessible, and most likely even tmpfs. */
202 if (flock(fd, LOCK_EX) < 0) {
203 close_nointr_nofail(fd);
211 SESSION_ID_AUDIT = 'a',
212 SESSION_ID_COUNTER = 'c',
213 SESSION_ID_RANDOM = 'r'
216 static uint64_t get_session_id(int *mode) {
222 /* First attempt: let's use the session ID of the audit
223 * system, if it is available. */
224 if (have_effective_cap(CAP_AUDIT_CONTROL) > 0)
225 if (read_one_line_file("/proc/self/sessionid", &s) >= 0) {
229 r = safe_atou32(s, &u);
232 if (r >= 0 && u != (uint32_t) -1 && u > 0) {
233 *mode = SESSION_ID_AUDIT;
238 /* Second attempt, use our own counter. */
239 if ((fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-session")) >= 0) {
243 /* We do a bit of endianess swapping here, just to be
244 * sure. /run should be machine specific anyway, and
245 * even mounted from tmpfs, so this byteswapping
246 * should really not be necessary. But then again, you
247 * never know, so let's avoid any risk. */
249 if (loop_read(fd, &counter, sizeof(counter), false) != sizeof(counter))
252 counter = le64toh(counter) + 1;
254 if (lseek(fd, 0, SEEK_SET) == 0) {
255 uint64_t swapped = htole64(counter);
257 r = loop_write(fd, &swapped, sizeof(swapped), false);
259 if (r != sizeof(swapped))
264 close_nointr_nofail(fd);
267 *mode = SESSION_ID_COUNTER;
272 *mode = SESSION_ID_RANDOM;
274 /* Last attempt, pick a random value */
275 return (uint64_t) random_ull();
278 static int get_user_data(
279 pam_handle_t *handle,
280 const char **ret_username,
281 struct passwd **ret_pw) {
283 const char *username = NULL;
284 struct passwd *pw = NULL;
286 bool have_loginuid = false;
290 assert(ret_username);
293 if (have_effective_cap(CAP_AUDIT_CONTROL) > 0) {
294 /* Only use audit login uid if we are executed with
295 * sufficient capabilities so that pam_loginuid could
296 * do its job. If we are lacking the CAP_AUDIT_CONTROL
297 * capabality we most likely are being run in a
298 * container and /proc/self/loginuid is useless since
299 * it probably contains a uid of the host system. */
301 if (read_one_line_file("/proc/self/loginuid", &s) >= 0) {
304 r = safe_atou32(s, &u);
307 if (r >= 0 && u != (uint32_t) -1 && u > 0) {
308 have_loginuid = true;
309 pw = pam_modutil_getpwuid(handle, u);
314 if (!have_loginuid) {
315 if ((r = pam_get_user(handle, &username, NULL)) != PAM_SUCCESS) {
316 pam_syslog(handle, LOG_ERR, "Failed to get user name.");
320 if (!username || !*username) {
321 pam_syslog(handle, LOG_ERR, "User name not valid.");
325 pw = pam_modutil_getpwnam(handle, username);
329 pam_syslog(handle, LOG_ERR, "Failed to get user data.");
330 return PAM_USER_UNKNOWN;
334 *ret_username = username ? username : pw->pw_name;
339 static int create_user_group(
340 pam_handle_t *handle,
341 const char *controller,
353 r = cg_create_and_attach(controller, group, 0);
355 r = cg_create(controller, group);
358 pam_syslog(handle, LOG_ERR, "Failed to create cgroup: %s", strerror(-r));
359 return PAM_SESSION_ERR;
362 if (r > 0 && remember) {
363 /* Remember that it was us who created this group, and
364 * that hence we need to remove it too. This is a
365 * protection against removing the cgroup when run
367 if ((r = pam_set_data(handle, "systemd.created", INT_TO_PTR(1), NULL)) != PAM_SUCCESS) {
368 pam_syslog(handle, LOG_ERR, "Failed to install created variable.");
373 if ((r = cg_set_task_access(controller, group, 0644, pw->pw_uid, pw->pw_gid)) < 0 ||
374 (r = cg_set_group_access(controller, group, 0755, pw->pw_uid, pw->pw_gid)) < 0) {
375 pam_syslog(handle, LOG_ERR, "Failed to change access modes: %s", strerror(-r));
376 return PAM_SESSION_ERR;
382 static int reset_group(
383 pam_handle_t *handle,
384 const char *controller) {
390 if ((r = cg_attach(controller, "/", 0)) < 0) {
391 pam_syslog(handle, LOG_ERR, "Failed to reset cgroup for controller %s: %s", controller, strerror(-r));
392 return PAM_SESSION_ERR;
398 _public_ PAM_EXTERN int pam_sm_open_session(
399 pam_handle_t *handle,
401 int argc, const char **argv) {
403 const char *username = NULL;
408 bool create_session = true;
409 char **controllers = NULL, **reset_controllers = NULL, **c;
410 char *cgroup_user_tree = NULL;
414 /* pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing"); */
416 /* Make this a NOP on non-systemd systems */
417 if (sd_booted() <= 0)
420 if (parse_argv(handle,
422 &create_session, NULL, NULL,
423 &controllers, &reset_controllers,
425 return PAM_SESSION_ERR;
427 if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
430 if ((r = cg_get_user_path(&cgroup_user_tree)) < 0) {
431 pam_syslog(handle, LOG_ERR, "Failed to determine user cgroup tree: %s", strerror(-r));
436 if (safe_mkdir(RUNTIME_DIR "/user", 0755, 0, 0) < 0) {
437 pam_syslog(handle, LOG_ERR, "Failed to create runtime directory: %m");
442 if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
443 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
448 /* Create /run/user/$USER */
450 if (asprintf(&buf, RUNTIME_DIR "/user/%s", username) < 0) {
455 if (safe_mkdir(buf, 0700, pw->pw_uid, pw->pw_gid) < 0) {
456 pam_syslog(handle, LOG_WARNING, "Failed to create runtime directory: %m");
459 } else if ((r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", buf, 0)) != PAM_SUCCESS) {
460 pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
467 if (create_session) {
470 /* Reuse or create XDG session ID */
471 if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
474 if (asprintf(&buf, "%llux", (unsigned long long) get_session_id(&mode)) < 0) {
479 /* To avoid id clashes we add the session id
480 * source to our session ids. Note that the
481 * session id source might change during
482 * runtime, because a filesystem became
483 * writable or the system reconfigured. */
485 mode != SESSION_ID_AUDIT ? (char) mode : 0;
487 if ((r = pam_misc_setenv(handle, "XDG_SESSION_ID", buf, 0)) != PAM_SUCCESS) {
488 pam_syslog(handle, LOG_ERR, "Failed to set session id.");
492 if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
493 pam_syslog(handle, LOG_ERR, "Failed to get session id.");
499 r = asprintf(&buf, "%s/%s/%s", cgroup_user_tree, username, id);
501 r = asprintf(&buf, "%s/%s/master", cgroup_user_tree, username);
508 pam_syslog(handle, LOG_DEBUG, "Moving new user session for %s into control group %s.", username, buf);
510 if ((r = create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, buf, pw, true, true)) != PAM_SUCCESS)
513 /* The additional controllers don't really matter, so we
514 * ignore the return value */
515 STRV_FOREACH(c, controllers)
516 create_user_group(handle, *c, buf, pw, true, false);
518 STRV_FOREACH(c, reset_controllers)
519 reset_group(handle, *c);
527 close_nointr_nofail(lock_fd);
529 strv_free(controllers);
530 strv_free(reset_controllers);
532 free(cgroup_user_tree);
537 static int session_remains(pam_handle_t *handle, const char *user_path) {
539 bool remains = false;
543 if ((r = cg_enumerate_subgroups(SYSTEMD_CGROUP_CONTROLLER, user_path, &d)) < 0)
546 while ((r = cg_read_subgroup(d, &subgroup)) > 0) {
548 remains = !streq(subgroup, "master");
563 static bool check_user_lists(
564 pam_handle_t *handle,
566 char **kill_only_users,
567 char **kill_exclude_users) {
569 const char *name = NULL;
575 name = "root"; /* Avoid obvious NSS requests, to suppress network traffic */
579 if ((pw = pam_modutil_getpwuid(handle, uid)))
583 STRV_FOREACH(l, kill_exclude_users) {
586 if (safe_atou32(*l, &id) >= 0)
587 if ((uid_t) id == uid)
590 if (name && streq(name, *l))
594 if (strv_isempty(kill_only_users))
597 STRV_FOREACH(l, kill_only_users) {
600 if (safe_atou32(*l, &id) >= 0)
601 if ((uid_t) id == uid)
604 if (name && streq(name, *l))
611 _public_ PAM_EXTERN int pam_sm_close_session(
612 pam_handle_t *handle,
614 int argc, const char **argv) {
616 const char *username = NULL;
617 bool kill_session = false;
618 bool kill_user = false;
620 char *session_path = NULL, *nosession_path = NULL, *user_path = NULL;
623 const void *created = NULL;
624 char **controllers = NULL, **c, **kill_only_users = NULL, **kill_exclude_users = NULL;
625 char *cgroup_user_tree = NULL;
629 /* Make this a NOP on non-systemd systems */
630 if (sd_booted() <= 0)
633 if (parse_argv(handle,
635 NULL, &kill_session, &kill_user,
637 &kill_only_users, &kill_exclude_users) < 0)
638 return PAM_SESSION_ERR;
640 if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
643 if ((r = cg_get_user_path(&cgroup_user_tree)) < 0) {
644 pam_syslog(handle, LOG_ERR, "Failed to determine user cgroup tree: %s", strerror(-r));
649 if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
650 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
655 /* We are probably still in some session/user dir. Move ourselves out of the way as first step */
656 if ((r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, cgroup_user_tree, 0)) < 0)
657 pam_syslog(handle, LOG_ERR, "Failed to move us away: %s", strerror(-r));
659 STRV_FOREACH(c, controllers)
660 if ((r = cg_attach(*c, cgroup_user_tree, 0)) < 0)
661 pam_syslog(handle, LOG_ERR, "Failed to move us away in %s hierarchy: %s", *c, strerror(-r));
663 if (asprintf(&user_path, "%s/%s", cgroup_user_tree, username) < 0) {
668 pam_get_data(handle, "systemd.created", &created);
670 if ((id = pam_getenv(handle, "XDG_SESSION_ID")) && created) {
672 if (asprintf(&session_path, "%s/%s/%s", cgroup_user_tree, username, id) < 0 ||
673 asprintf(&nosession_path, "%s/%s/master", cgroup_user_tree, username) < 0) {
678 if (kill_session && check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users)) {
679 pam_syslog(handle, LOG_DEBUG, "Killing remaining processes of user session %s of %s.", id, username);
681 /* Kill processes in session cgroup, and delete it */
682 if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, session_path, true)) < 0)
683 pam_syslog(handle, LOG_ERR, "Failed to kill session cgroup: %s", strerror(-r));
685 pam_syslog(handle, LOG_DEBUG, "Moving remaining processes of user session %s of %s into control group %s.", id, username, nosession_path);
687 /* Migrate processes from session to user
688 * cgroup. First, try to create the user group
689 * in case it doesn't exist yet. Also, delete
690 * the session group. */
691 create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, nosession_path, pw, false, false);
693 if ((r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, session_path, nosession_path, false, true)) < 0)
694 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup: %s", strerror(-r));
697 STRV_FOREACH(c, controllers) {
698 create_user_group(handle, *c, nosession_path, pw, false, false);
700 if ((r = cg_migrate_recursive(*c, session_path, nosession_path, false, true)) < 0)
701 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup in hierarchy %s: %s", *c, strerror(-r));
706 cg_trim(SYSTEMD_CGROUP_CONTROLLER, user_path, false);
708 if ((r = session_remains(handle, user_path)) < 0)
709 pam_syslog(handle, LOG_ERR, "Failed to determine whether a session remains: %s", strerror(-r));
711 /* Kill user processes not attached to any session */
712 if (kill_user && r == 0 && check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users)) {
714 /* Kill user cgroup */
715 if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
716 pam_syslog(handle, LOG_ERR, "Failed to kill user cgroup: %s", strerror(-r));
719 if ((r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
720 pam_syslog(handle, LOG_ERR, "Failed to check user cgroup: %s", strerror(-r));
722 /* Remove user cgroup */
724 if ((r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, user_path)) < 0)
725 pam_syslog(handle, LOG_ERR, "Failed to delete user cgroup: %s", strerror(-r));
727 /* If we managed to find somebody, don't cleanup the cgroup. */
732 STRV_FOREACH(c, controllers)
733 cg_trim(*c, user_path, true);
736 const char *runtime_dir;
738 if ((runtime_dir = pam_getenv(handle, "XDG_RUNTIME_DIR")))
739 if ((r = rm_rf(runtime_dir, false, true)) < 0)
740 pam_syslog(handle, LOG_ERR, "Failed to remove runtime directory: %s", strerror(-r));
743 /* pam_syslog(handle, LOG_DEBUG, "pam-systemd done"); */
749 close_nointr_nofail(lock_fd);
752 free(nosession_path);
755 strv_free(controllers);
756 strv_free(kill_exclude_users);
757 strv_free(kill_only_users);
759 free(cgroup_user_tree);