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 ***controllers) {
49 bool controller_set = false;
52 assert(argc == 0 || argv);
54 for (i = 0; i < (unsigned) argc; i++) {
57 if (startswith(argv[i], "create-session=")) {
58 if ((k = parse_boolean(argv[i] + 15)) < 0) {
59 pam_syslog(handle, LOG_ERR, "Failed to parse create-session= argument.");
66 } else if (startswith(argv[i], "kill-session=")) {
67 if ((k = parse_boolean(argv[i] + 13)) < 0) {
68 pam_syslog(handle, LOG_ERR, "Failed to parse kill-session= argument.");
75 } else if (startswith(argv[i], "kill-user=")) {
76 if ((k = parse_boolean(argv[i] + 10)) < 0) {
77 pam_syslog(handle, LOG_ERR, "Failed to parse kill-user= argument.");
84 } else if (startswith(argv[i], "keep-root=")) {
85 if ((k = parse_boolean(argv[i] + 10)) < 0) {
86 pam_syslog(handle, LOG_ERR, "Failed to parse keep-root= argument.");
93 } else if (startswith(argv[i], "controllers=")) {
98 if (!(l = strv_split(argv[i] + 12, ","))) {
99 pam_syslog(handle, LOG_ERR, "Out of memory.");
103 strv_free(*controllers);
107 controller_set = true;
110 pam_syslog(handle, LOG_ERR, "Unknown parameter '%s'.", argv[i]);
116 if (!controller_set && controllers) {
119 if (!(l = strv_new("cpu", NULL))) {
120 pam_syslog(handle, LOG_ERR, "Out of memory");
129 strv_remove(*controllers, "name=systemd");
131 if (kill_session && *kill_session && kill_user)
137 static int open_file_and_lock(const char *fn) {
142 if ((fd = open(fn, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_CREAT, 0600)) < 0)
145 /* The BSD socket semantics are a lot nicer than those of
146 * POSIX locks. Which is why we use flock() here. BSD locking
147 * does not work across NFS which however is not needed here
148 * as the filesystems in question should be local, and only
149 * locally accessible, and most likely even tmpfs. */
151 if (flock(fd, LOCK_EX) < 0)
158 SESSION_ID_AUDIT = 'a',
159 SESSION_ID_COUNTER = 'c',
160 SESSION_ID_RANDOM = 'r'
163 static uint64_t get_session_id(int *mode) {
169 /* First attempt: let's use the session ID of the audit
170 * system, if it is available. */
171 if (read_one_line_file("/proc/self/sessionid", &s) >= 0) {
175 r = safe_atou32(s, &u);
178 if (r >= 0 && u != (uint32_t) -1 && u > 0) {
179 *mode = SESSION_ID_AUDIT;
184 /* Second attempt, use our own counter. */
185 if ((fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-session")) >= 0) {
189 /* We do a bit of endianess swapping here, just to be
190 * sure. /var should be machine specific anyway, and
191 * /var/run even mounted from tmpfs, so this
192 * byteswapping should really not be necessary. But
193 * then again, you never know, so let's avoid any
196 if (loop_read(fd, &counter, sizeof(counter), false) != sizeof(counter))
199 counter = le64toh(counter) + 1;
201 if (lseek(fd, 0, SEEK_SET) == 0) {
202 uint64_t swapped = htole64(counter);
204 r = loop_write(fd, &swapped, sizeof(swapped), false);
206 if (r != sizeof(swapped))
211 close_nointr_nofail(fd);
214 *mode = SESSION_ID_COUNTER;
219 *mode = SESSION_ID_RANDOM;
221 /* Last attempt, pick a random value */
222 return (uint64_t) random_ull();
224 static int get_user_data(
225 pam_handle_t *handle,
226 const char **ret_username,
227 struct passwd **ret_pw) {
229 const char *username = NULL;
230 struct passwd *pw = NULL;
232 bool have_loginuid = false;
236 assert(ret_username);
239 if (read_one_line_file("/proc/self/loginuid", &s) >= 0) {
242 r = safe_atou32(s, &u);
245 if (r >= 0 && u != (uint32_t) -1 && u > 0) {
246 have_loginuid = true;
247 pw = pam_modutil_getpwuid(handle, u);
251 if (!have_loginuid) {
252 if ((r = pam_get_user(handle, &username, NULL)) != PAM_SUCCESS) {
253 pam_syslog(handle, LOG_ERR, "Failed to get user name.");
257 if (!username || !*username) {
258 pam_syslog(handle, LOG_ERR, "User name not valid.");
262 pw = pam_modutil_getpwnam(handle, username);
266 pam_syslog(handle, LOG_ERR, "Failed to get user data.");
267 return PAM_USER_UNKNOWN;
271 *ret_username = username ? username : pw->pw_name;
276 static int create_user_group(
277 pam_handle_t *handle,
278 const char *controller,
290 r = cg_create_and_attach(controller, group, 0);
292 r = cg_create(controller, group);
295 pam_syslog(handle, LOG_ERR, "Failed to create cgroup: %s", strerror(-r));
296 return PAM_SESSION_ERR;
299 if (r > 0 && remember) {
300 /* Remember that it was us who created this group, and
301 * that hence we need to remove it too. This is a
302 * protection against removing the cgroup when run
304 if ((r = pam_set_data(handle, "systemd.created", INT_TO_PTR(1), NULL)) != PAM_SUCCESS) {
305 pam_syslog(handle, LOG_ERR, "Failed to install created variable.");
310 if ((r = cg_set_task_access(controller, group, 0644, pw->pw_uid, pw->pw_gid)) < 0 ||
311 (r = cg_set_group_access(controller, group, 0755, pw->pw_uid, pw->pw_gid)) < 0) {
312 pam_syslog(handle, LOG_ERR, "Failed to change access modes: %s", strerror(-r));
313 return PAM_SESSION_ERR;
319 _public_ PAM_EXTERN int pam_sm_open_session(
320 pam_handle_t *handle,
322 int argc, const char **argv) {
324 const char *username = NULL;
329 bool create_session = true;
330 char **controllers = NULL, **c;
334 /* pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing"); */
336 /* Make this a NOP on non-systemd systems */
337 if (sd_booted() <= 0)
340 if (parse_argv(handle, argc, argv, &create_session, NULL, NULL, NULL, &controllers) < 0)
341 return PAM_SESSION_ERR;
343 if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
346 if (safe_mkdir(RUNTIME_DIR "/user", 0755, 0, 0) < 0) {
347 pam_syslog(handle, LOG_ERR, "Failed to create runtime directory: %m");
352 if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
353 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
358 /* Create /var/run/$USER */
360 if (asprintf(&buf, RUNTIME_DIR "/user/%s", username) < 0) {
365 if (safe_mkdir(buf, 0700, pw->pw_uid, pw->pw_gid) < 0) {
366 pam_syslog(handle, LOG_WARNING, "Failed to create runtime directory: %m");
369 } else if ((r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", buf, 0)) != PAM_SUCCESS) {
370 pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
377 if (create_session) {
380 /* Reuse or create XDG session ID */
381 if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
384 if (asprintf(&buf, "%llux", (unsigned long long) get_session_id(&mode)) < 0) {
389 /* To avoid id clashes we add the session id
390 * source to our session ids. Note that the
391 * session id source might change during
392 * runtime, because a filesystem became
393 * writable or the system reconfigured. */
395 mode != SESSION_ID_AUDIT ? (char) mode : 0;
397 if ((r = pam_misc_setenv(handle, "XDG_SESSION_ID", buf, 0)) != PAM_SUCCESS) {
398 pam_syslog(handle, LOG_ERR, "Failed to set session id.");
402 if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
403 pam_syslog(handle, LOG_ERR, "Failed to get session id.");
409 r = asprintf(&buf, "/user/%s/%s", username, id);
411 r = asprintf(&buf, "/user/%s/master", username);
418 pam_syslog(handle, LOG_INFO, "Moving new user session for %s into control group %s.", username, buf);
420 if ((r = create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, buf, pw, true, true)) != PAM_SUCCESS)
423 /* The additional controllers don't really matter, so we
424 * ignore the return value */
425 STRV_FOREACH(c, controllers)
426 create_user_group(handle, *c, buf, pw, true, false);
434 close_nointr_nofail(lock_fd);
436 strv_free(controllers);
441 static int session_remains(pam_handle_t *handle, const char *user_path) {
443 bool remains = false;
447 if ((r = cg_enumerate_subgroups(SYSTEMD_CGROUP_CONTROLLER, user_path, &d)) < 0)
450 while ((r = cg_read_subgroup(d, &subgroup)) > 0) {
452 remains = !streq(subgroup, "master");
467 _public_ PAM_EXTERN int pam_sm_close_session(
468 pam_handle_t *handle,
470 int argc, const char **argv) {
472 const char *username = NULL;
473 bool kill_session = false;
474 bool kill_user = false;
475 bool keep_root = true;
477 char *session_path = NULL, *nosession_path = NULL, *user_path = NULL;
480 const void *created = NULL;
481 char **controllers = NULL, **c;
485 /* Make this a NOP on non-systemd systems */
486 if (sd_booted() <= 0)
489 if (parse_argv(handle, argc, argv, NULL, &kill_session, &kill_user, &keep_root, &controllers) < 0)
490 return PAM_SESSION_ERR;
492 if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
495 if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
496 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
501 /* We are probably still in some session/user dir. Move ourselves out of the way as first step */
502 if ((r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, "/user", 0)) < 0)
503 pam_syslog(handle, LOG_ERR, "Failed to move us away: %s", strerror(-r));
505 STRV_FOREACH(c, controllers)
506 if ((r = cg_attach(*c, "/user", 0)) < 0)
507 pam_syslog(handle, LOG_ERR, "Failed to move us away in %s hierarchy: %s", *c, strerror(-r));
509 if (asprintf(&user_path, "/user/%s", username) < 0) {
514 pam_get_data(handle, "systemd.created", &created);
516 if ((id = pam_getenv(handle, "XDG_SESSION_ID")) && created) {
518 if (asprintf(&session_path, "/user/%s/%s", username, id) < 0 ||
519 asprintf(&nosession_path, "/user/%s/master", username) < 0) {
524 if (kill_session && (pw->pw_uid != 0 || !keep_root)) {
525 pam_syslog(handle, LOG_INFO, "Killing remaining processes of user session %s of %s.", id, username);
527 /* Kill processes in session cgroup, and delete it */
528 if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, session_path, true)) < 0)
529 pam_syslog(handle, LOG_ERR, "Failed to kill session cgroup: %s", strerror(-r));
531 pam_syslog(handle, LOG_INFO, "Moving remaining processes of user session %s of %s into control group %s.", id, username, nosession_path);
533 /* Migrate processes from session to user
534 * cgroup. First, try to create the user group
535 * in case it doesn't exist yet. Also, delete
536 * the session group. */
537 create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, nosession_path, pw, false, false);
539 if ((r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, session_path, nosession_path, false, true)) < 0)
540 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup: %s", strerror(-r));
543 STRV_FOREACH(c, controllers) {
544 create_user_group(handle, *c, nosession_path, pw, false, false);
546 if ((r = cg_migrate_recursive(*c, session_path, nosession_path, false, true)) < 0)
547 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup in hierarchy %s: %s", *c, strerror(-r));
552 cg_trim(SYSTEMD_CGROUP_CONTROLLER, user_path, false);
554 if ((r = session_remains(handle, user_path)) < 0)
555 pam_syslog(handle, LOG_ERR, "Failed to determine whether a session remains: %s", strerror(-r));
557 /* Kill user processes not attached to any session */
558 if (kill_user && r == 0 && (pw->pw_uid != 0 || !keep_root)) {
560 /* Kill user cgroup */
561 if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
562 pam_syslog(handle, LOG_ERR, "Failed to kill user cgroup: %s", strerror(-r));
565 if ((r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
566 pam_syslog(handle, LOG_ERR, "Failed to check user cgroup: %s", strerror(-r));
568 /* Remove user cgroup */
570 if ((r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, user_path)) < 0)
571 pam_syslog(handle, LOG_ERR, "Failed to delete user cgroup: %s", strerror(-r));
573 /* If we managed to find somebody, don't cleanup the cgroup. */
578 STRV_FOREACH(c, controllers)
579 cg_trim(*c, user_path, true);
582 const char *runtime_dir;
584 if ((runtime_dir = pam_getenv(handle, "XDG_RUNTIME_DIR")))
585 if ((r = rm_rf(runtime_dir, false, true)) < 0)
586 pam_syslog(handle, LOG_ERR, "Failed to remove runtime directory: %s", strerror(-r));
589 /* pam_syslog(handle, LOG_DEBUG, "pam-systemd done"); */
595 close_nointr_nofail(lock_fd);
598 free(nosession_path);
601 strv_free(controllers);