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,
47 char ***reset_controllers) {
50 bool reset_controller_set = false;
53 assert(argc == 0 || argv);
55 for (i = 0; i < (unsigned) argc; i++) {
58 if (startswith(argv[i], "create-session=")) {
59 if ((k = parse_boolean(argv[i] + 15)) < 0) {
60 pam_syslog(handle, LOG_ERR, "Failed to parse create-session= argument.");
67 } else if (startswith(argv[i], "kill-session=")) {
68 if ((k = parse_boolean(argv[i] + 13)) < 0) {
69 pam_syslog(handle, LOG_ERR, "Failed to parse kill-session= argument.");
76 } else if (startswith(argv[i], "kill-user=")) {
77 if ((k = parse_boolean(argv[i] + 10)) < 0) {
78 pam_syslog(handle, LOG_ERR, "Failed to parse kill-user= argument.");
85 } else if (startswith(argv[i], "keep-root=")) {
86 if ((k = parse_boolean(argv[i] + 10)) < 0) {
87 pam_syslog(handle, LOG_ERR, "Failed to parse keep-root= argument.");
94 } else if (startswith(argv[i], "controllers=")) {
99 if (!(l = strv_split(argv[i] + 12, ","))) {
100 pam_syslog(handle, LOG_ERR, "Out of memory.");
104 strv_free(*controllers);
108 } else if (startswith(argv[i], "reset-controllers=")) {
110 if (reset_controllers) {
113 if (!(l = strv_split(argv[i] + 18, ","))) {
114 pam_syslog(handle, LOG_ERR, "Out of memory.");
118 strv_free(*reset_controllers);
119 *reset_controllers = l;
122 reset_controller_set = true;
125 pam_syslog(handle, LOG_ERR, "Unknown parameter '%s'.", argv[i]);
130 if (!reset_controller_set && reset_controllers) {
133 if (!(l = strv_new("cpu", NULL))) {
134 pam_syslog(handle, LOG_ERR, "Out of memory");
138 *reset_controllers = l;
142 strv_remove(*controllers, "name=systemd");
144 if (reset_controllers)
145 strv_remove(*reset_controllers, "name=systemd");
147 if (kill_session && *kill_session && kill_user)
153 static int open_file_and_lock(const char *fn) {
158 if ((fd = open(fn, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_CREAT, 0600)) < 0)
161 /* The BSD socket semantics are a lot nicer than those of
162 * POSIX locks. Which is why we use flock() here. BSD locking
163 * does not work across NFS which however is not needed here
164 * as the filesystems in question should be local, and only
165 * locally accessible, and most likely even tmpfs. */
167 if (flock(fd, LOCK_EX) < 0)
174 SESSION_ID_AUDIT = 'a',
175 SESSION_ID_COUNTER = 'c',
176 SESSION_ID_RANDOM = 'r'
179 static uint64_t get_session_id(int *mode) {
185 /* First attempt: let's use the session ID of the audit
186 * system, if it is available. */
187 if (read_one_line_file("/proc/self/sessionid", &s) >= 0) {
191 r = safe_atou32(s, &u);
194 if (r >= 0 && u != (uint32_t) -1 && u > 0) {
195 *mode = SESSION_ID_AUDIT;
200 /* Second attempt, use our own counter. */
201 if ((fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-session")) >= 0) {
205 /* We do a bit of endianess swapping here, just to be
206 * sure. /var should be machine specific anyway, and
207 * /var/run even mounted from tmpfs, so this
208 * byteswapping should really not be necessary. But
209 * then again, you never know, so let's avoid any
212 if (loop_read(fd, &counter, sizeof(counter), false) != sizeof(counter))
215 counter = le64toh(counter) + 1;
217 if (lseek(fd, 0, SEEK_SET) == 0) {
218 uint64_t swapped = htole64(counter);
220 r = loop_write(fd, &swapped, sizeof(swapped), false);
222 if (r != sizeof(swapped))
227 close_nointr_nofail(fd);
230 *mode = SESSION_ID_COUNTER;
235 *mode = SESSION_ID_RANDOM;
237 /* Last attempt, pick a random value */
238 return (uint64_t) random_ull();
240 static int get_user_data(
241 pam_handle_t *handle,
242 const char **ret_username,
243 struct passwd **ret_pw) {
245 const char *username = NULL;
246 struct passwd *pw = NULL;
248 bool have_loginuid = false;
252 assert(ret_username);
255 if (read_one_line_file("/proc/self/loginuid", &s) >= 0) {
258 r = safe_atou32(s, &u);
261 if (r >= 0 && u != (uint32_t) -1 && u > 0) {
262 have_loginuid = true;
263 pw = pam_modutil_getpwuid(handle, u);
267 if (!have_loginuid) {
268 if ((r = pam_get_user(handle, &username, NULL)) != PAM_SUCCESS) {
269 pam_syslog(handle, LOG_ERR, "Failed to get user name.");
273 if (!username || !*username) {
274 pam_syslog(handle, LOG_ERR, "User name not valid.");
278 pw = pam_modutil_getpwnam(handle, username);
282 pam_syslog(handle, LOG_ERR, "Failed to get user data.");
283 return PAM_USER_UNKNOWN;
287 *ret_username = username ? username : pw->pw_name;
292 static int create_user_group(
293 pam_handle_t *handle,
294 const char *controller,
306 r = cg_create_and_attach(controller, group, 0);
308 r = cg_create(controller, group);
311 pam_syslog(handle, LOG_ERR, "Failed to create cgroup: %s", strerror(-r));
312 return PAM_SESSION_ERR;
315 if (r > 0 && remember) {
316 /* Remember that it was us who created this group, and
317 * that hence we need to remove it too. This is a
318 * protection against removing the cgroup when run
320 if ((r = pam_set_data(handle, "systemd.created", INT_TO_PTR(1), NULL)) != PAM_SUCCESS) {
321 pam_syslog(handle, LOG_ERR, "Failed to install created variable.");
326 if ((r = cg_set_task_access(controller, group, 0644, pw->pw_uid, pw->pw_gid)) < 0 ||
327 (r = cg_set_group_access(controller, group, 0755, pw->pw_uid, pw->pw_gid)) < 0) {
328 pam_syslog(handle, LOG_ERR, "Failed to change access modes: %s", strerror(-r));
329 return PAM_SESSION_ERR;
335 static int reset_group(
336 pam_handle_t *handle,
337 const char *controller) {
343 if ((r = cg_attach(controller, "/", 0)) < 0) {
344 pam_syslog(handle, LOG_ERR, "Failed to reset cgroup for controller %s: %s", controller, strerror(-r));
345 return PAM_SESSION_ERR;
351 _public_ PAM_EXTERN int pam_sm_open_session(
352 pam_handle_t *handle,
354 int argc, const char **argv) {
356 const char *username = NULL;
361 bool create_session = true;
362 char **controllers = NULL, **reset_controllers = NULL, **c;
366 /* pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing"); */
368 /* Make this a NOP on non-systemd systems */
369 if (sd_booted() <= 0)
372 if (parse_argv(handle, argc, argv, &create_session, NULL, NULL, NULL, &controllers, &reset_controllers) < 0)
373 return PAM_SESSION_ERR;
375 if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
378 if (safe_mkdir(RUNTIME_DIR "/user", 0755, 0, 0) < 0) {
379 pam_syslog(handle, LOG_ERR, "Failed to create runtime directory: %m");
384 if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
385 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
390 /* Create /var/run/$USER */
392 if (asprintf(&buf, RUNTIME_DIR "/user/%s", username) < 0) {
397 if (safe_mkdir(buf, 0700, pw->pw_uid, pw->pw_gid) < 0) {
398 pam_syslog(handle, LOG_WARNING, "Failed to create runtime directory: %m");
401 } else if ((r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", buf, 0)) != PAM_SUCCESS) {
402 pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
409 if (create_session) {
412 /* Reuse or create XDG session ID */
413 if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
416 if (asprintf(&buf, "%llux", (unsigned long long) get_session_id(&mode)) < 0) {
421 /* To avoid id clashes we add the session id
422 * source to our session ids. Note that the
423 * session id source might change during
424 * runtime, because a filesystem became
425 * writable or the system reconfigured. */
427 mode != SESSION_ID_AUDIT ? (char) mode : 0;
429 if ((r = pam_misc_setenv(handle, "XDG_SESSION_ID", buf, 0)) != PAM_SUCCESS) {
430 pam_syslog(handle, LOG_ERR, "Failed to set session id.");
434 if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
435 pam_syslog(handle, LOG_ERR, "Failed to get session id.");
441 r = asprintf(&buf, "/user/%s/%s", username, id);
443 r = asprintf(&buf, "/user/%s/master", username);
450 pam_syslog(handle, LOG_INFO, "Moving new user session for %s into control group %s.", username, buf);
452 if ((r = create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, buf, pw, true, true)) != PAM_SUCCESS)
455 /* The additional controllers don't really matter, so we
456 * ignore the return value */
457 STRV_FOREACH(c, controllers)
458 create_user_group(handle, *c, buf, pw, true, false);
460 STRV_FOREACH(c, reset_controllers)
461 reset_group(handle, *c);
469 close_nointr_nofail(lock_fd);
471 strv_free(controllers);
472 strv_free(reset_controllers);
477 static int session_remains(pam_handle_t *handle, const char *user_path) {
479 bool remains = false;
483 if ((r = cg_enumerate_subgroups(SYSTEMD_CGROUP_CONTROLLER, user_path, &d)) < 0)
486 while ((r = cg_read_subgroup(d, &subgroup)) > 0) {
488 remains = !streq(subgroup, "master");
503 _public_ PAM_EXTERN int pam_sm_close_session(
504 pam_handle_t *handle,
506 int argc, const char **argv) {
508 const char *username = NULL;
509 bool kill_session = false;
510 bool kill_user = false;
511 bool keep_root = true;
513 char *session_path = NULL, *nosession_path = NULL, *user_path = NULL;
516 const void *created = NULL;
517 char **controllers = NULL, **c;
521 /* Make this a NOP on non-systemd systems */
522 if (sd_booted() <= 0)
525 if (parse_argv(handle, argc, argv, NULL, &kill_session, &kill_user, &keep_root, &controllers, NULL) < 0)
526 return PAM_SESSION_ERR;
528 if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
531 if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
532 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
537 /* We are probably still in some session/user dir. Move ourselves out of the way as first step */
538 if ((r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, "/user", 0)) < 0)
539 pam_syslog(handle, LOG_ERR, "Failed to move us away: %s", strerror(-r));
541 STRV_FOREACH(c, controllers)
542 if ((r = cg_attach(*c, "/user", 0)) < 0)
543 pam_syslog(handle, LOG_ERR, "Failed to move us away in %s hierarchy: %s", *c, strerror(-r));
545 if (asprintf(&user_path, "/user/%s", username) < 0) {
550 pam_get_data(handle, "systemd.created", &created);
552 if ((id = pam_getenv(handle, "XDG_SESSION_ID")) && created) {
554 if (asprintf(&session_path, "/user/%s/%s", username, id) < 0 ||
555 asprintf(&nosession_path, "/user/%s/master", username) < 0) {
560 if (kill_session && (pw->pw_uid != 0 || !keep_root)) {
561 pam_syslog(handle, LOG_INFO, "Killing remaining processes of user session %s of %s.", id, username);
563 /* Kill processes in session cgroup, and delete it */
564 if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, session_path, true)) < 0)
565 pam_syslog(handle, LOG_ERR, "Failed to kill session cgroup: %s", strerror(-r));
567 pam_syslog(handle, LOG_INFO, "Moving remaining processes of user session %s of %s into control group %s.", id, username, nosession_path);
569 /* Migrate processes from session to user
570 * cgroup. First, try to create the user group
571 * in case it doesn't exist yet. Also, delete
572 * the session group. */
573 create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, nosession_path, pw, false, false);
575 if ((r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, session_path, nosession_path, false, true)) < 0)
576 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup: %s", strerror(-r));
579 STRV_FOREACH(c, controllers) {
580 create_user_group(handle, *c, nosession_path, pw, false, false);
582 if ((r = cg_migrate_recursive(*c, session_path, nosession_path, false, true)) < 0)
583 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup in hierarchy %s: %s", *c, strerror(-r));
588 cg_trim(SYSTEMD_CGROUP_CONTROLLER, user_path, false);
590 if ((r = session_remains(handle, user_path)) < 0)
591 pam_syslog(handle, LOG_ERR, "Failed to determine whether a session remains: %s", strerror(-r));
593 /* Kill user processes not attached to any session */
594 if (kill_user && r == 0 && (pw->pw_uid != 0 || !keep_root)) {
596 /* Kill user cgroup */
597 if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
598 pam_syslog(handle, LOG_ERR, "Failed to kill user cgroup: %s", strerror(-r));
601 if ((r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
602 pam_syslog(handle, LOG_ERR, "Failed to check user cgroup: %s", strerror(-r));
604 /* Remove user cgroup */
606 if ((r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, user_path)) < 0)
607 pam_syslog(handle, LOG_ERR, "Failed to delete user cgroup: %s", strerror(-r));
609 /* If we managed to find somebody, don't cleanup the cgroup. */
614 STRV_FOREACH(c, controllers)
615 cg_trim(*c, user_path, true);
618 const char *runtime_dir;
620 if ((runtime_dir = pam_getenv(handle, "XDG_RUNTIME_DIR")))
621 if ((r = rm_rf(runtime_dir, false, true)) < 0)
622 pam_syslog(handle, LOG_ERR, "Failed to remove runtime directory: %s", strerror(-r));
625 /* pam_syslog(handle, LOG_DEBUG, "pam-systemd done"); */
631 close_nointr_nofail(lock_fd);
634 free(nosession_path);
637 strv_free(controllers);