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
,
53 bool reset_controller_set
= false;
54 bool kill_exclude_users_set
= false;
57 assert(argc
== 0 || argv
);
59 for (i
= 0; i
< (unsigned) argc
; i
++) {
62 if (startswith(argv
[i
], "create-session=")) {
63 if ((k
= parse_boolean(argv
[i
] + 15)) < 0) {
64 pam_syslog(handle
, LOG_ERR
, "Failed to parse create-session= argument.");
71 } else if (startswith(argv
[i
], "kill-session=")) {
72 if ((k
= parse_boolean(argv
[i
] + 13)) < 0) {
73 pam_syslog(handle
, LOG_ERR
, "Failed to parse kill-session= argument.");
80 } else if (startswith(argv
[i
], "kill-user=")) {
81 if ((k
= parse_boolean(argv
[i
] + 10)) < 0) {
82 pam_syslog(handle
, LOG_ERR
, "Failed to parse kill-user= argument.");
89 } else if (startswith(argv
[i
], "controllers=")) {
94 if (!(l
= strv_split(argv
[i
] + 12, ","))) {
95 pam_syslog(handle
, LOG_ERR
, "Out of memory.");
99 strv_free(*controllers
);
103 } else if (startswith(argv
[i
], "reset-controllers=")) {
105 if (reset_controllers
) {
108 if (!(l
= strv_split(argv
[i
] + 18, ","))) {
109 pam_syslog(handle
, LOG_ERR
, "Out of memory.");
113 strv_free(*reset_controllers
);
114 *reset_controllers
= l
;
117 reset_controller_set
= true;
119 } else if (startswith(argv
[i
], "kill-only-users=")) {
121 if (kill_only_users
) {
124 if (!(l
= strv_split(argv
[i
] + 16, ","))) {
125 pam_syslog(handle
, LOG_ERR
, "Out of memory.");
129 strv_free(*kill_only_users
);
130 *kill_only_users
= l
;
133 } else if (startswith(argv
[i
], "kill-exclude-users=")) {
135 if (kill_exclude_users
) {
138 if (!(l
= strv_split(argv
[i
] + 19, ","))) {
139 pam_syslog(handle
, LOG_ERR
, "Out of memory.");
143 strv_free(*kill_exclude_users
);
144 *kill_exclude_users
= l
;
147 kill_exclude_users_set
= true;
149 } else if (startswith(argv
[i
], "debug=")) {
150 if ((k
= parse_boolean(argv
[i
] + 6)) < 0) {
151 pam_syslog(handle
, LOG_ERR
, "Failed to parse debug= argument.");
159 pam_syslog(handle
, LOG_ERR
, "Unknown parameter '%s'.", argv
[i
]);
164 if (!reset_controller_set
&& reset_controllers
) {
167 if (!(l
= strv_new("cpu", NULL
))) {
168 pam_syslog(handle
, LOG_ERR
, "Out of memory");
172 *reset_controllers
= l
;
176 strv_remove(*controllers
, "name=systemd");
178 if (reset_controllers
)
179 strv_remove(*reset_controllers
, "name=systemd");
181 if (kill_session
&& *kill_session
&& kill_user
)
184 if (!kill_exclude_users_set
&& kill_exclude_users
) {
187 if (!(l
= strv_new("root", NULL
))) {
188 pam_syslog(handle
, LOG_ERR
, "Out of memory");
192 *kill_exclude_users
= l
;
198 static int open_file_and_lock(const char *fn
) {
203 if ((fd
= open(fn
, O_RDWR
|O_CLOEXEC
|O_NOCTTY
|O_NOFOLLOW
|O_CREAT
, 0600)) < 0)
206 /* The BSD socket semantics are a lot nicer than those of
207 * POSIX locks. Which is why we use flock() here. BSD locking
208 * does not work across NFS which however is not needed here
209 * as the filesystems in question should be local, and only
210 * locally accessible, and most likely even tmpfs. */
212 if (flock(fd
, LOCK_EX
) < 0) {
213 close_nointr_nofail(fd
);
221 SESSION_ID_AUDIT
= 'a',
222 SESSION_ID_COUNTER
= 'c',
223 SESSION_ID_RANDOM
= 'r'
226 static uint64_t get_session_id(int *mode
) {
232 /* First attempt: let's use the session ID of the audit
233 * system, if it is available. */
234 if (have_effective_cap(CAP_AUDIT_CONTROL
) > 0)
235 if (read_one_line_file("/proc/self/sessionid", &s
) >= 0) {
239 r
= safe_atou32(s
, &u
);
242 if (r
>= 0 && u
!= (uint32_t) -1 && u
> 0) {
243 *mode
= SESSION_ID_AUDIT
;
248 /* Second attempt, use our own counter. */
249 if ((fd
= open_file_and_lock(RUNTIME_DIR
"/user/.pam-systemd-session")) >= 0) {
253 /* We do a bit of endianess swapping here, just to be
254 * sure. /run should be machine specific anyway, and
255 * even mounted from tmpfs, so this byteswapping
256 * should really not be necessary. But then again, you
257 * never know, so let's avoid any risk. */
259 if (loop_read(fd
, &counter
, sizeof(counter
), false) != sizeof(counter
))
262 counter
= le64toh(counter
) + 1;
264 if (lseek(fd
, 0, SEEK_SET
) == 0) {
265 uint64_t swapped
= htole64(counter
);
267 r
= loop_write(fd
, &swapped
, sizeof(swapped
), false);
269 if (r
!= sizeof(swapped
))
274 close_nointr_nofail(fd
);
277 *mode
= SESSION_ID_COUNTER
;
282 *mode
= SESSION_ID_RANDOM
;
284 /* Last attempt, pick a random value */
285 return (uint64_t) random_ull();
288 static int get_user_data(
289 pam_handle_t
*handle
,
290 const char **ret_username
,
291 struct passwd
**ret_pw
) {
293 const char *username
= NULL
;
294 struct passwd
*pw
= NULL
;
296 bool have_loginuid
= false;
300 assert(ret_username
);
303 if (have_effective_cap(CAP_AUDIT_CONTROL
) > 0) {
304 /* Only use audit login uid if we are executed with
305 * sufficient capabilities so that pam_loginuid could
306 * do its job. If we are lacking the CAP_AUDIT_CONTROL
307 * capabality we most likely are being run in a
308 * container and /proc/self/loginuid is useless since
309 * it probably contains a uid of the host system. */
311 if (read_one_line_file("/proc/self/loginuid", &s
) >= 0) {
314 r
= safe_atou32(s
, &u
);
317 if (r
>= 0 && u
!= (uint32_t) -1 && u
> 0) {
318 have_loginuid
= true;
319 pw
= pam_modutil_getpwuid(handle
, u
);
324 if (!have_loginuid
) {
325 if ((r
= pam_get_user(handle
, &username
, NULL
)) != PAM_SUCCESS
) {
326 pam_syslog(handle
, LOG_ERR
, "Failed to get user name.");
330 if (!username
|| !*username
) {
331 pam_syslog(handle
, LOG_ERR
, "User name not valid.");
335 pw
= pam_modutil_getpwnam(handle
, username
);
339 pam_syslog(handle
, LOG_ERR
, "Failed to get user data.");
340 return PAM_USER_UNKNOWN
;
344 *ret_username
= username
? username
: pw
->pw_name
;
349 static int create_user_group(
350 pam_handle_t
*handle
,
351 const char *controller
,
363 r
= cg_create_and_attach(controller
, group
, 0);
365 r
= cg_create(controller
, group
);
368 pam_syslog(handle
, LOG_ERR
, "Failed to create cgroup: %s", strerror(-r
));
369 return PAM_SESSION_ERR
;
372 if (r
> 0 && remember
) {
373 /* Remember that it was us who created this group, and
374 * that hence we need to remove it too. This is a
375 * protection against removing the cgroup when run
377 if ((r
= pam_set_data(handle
, "systemd.created", INT_TO_PTR(1), NULL
)) != PAM_SUCCESS
) {
378 pam_syslog(handle
, LOG_ERR
, "Failed to install created variable.");
383 if ((r
= cg_set_task_access(controller
, group
, 0644, pw
->pw_uid
, pw
->pw_gid
)) < 0 ||
384 (r
= cg_set_group_access(controller
, group
, 0755, pw
->pw_uid
, pw
->pw_gid
)) < 0) {
385 pam_syslog(handle
, LOG_ERR
, "Failed to change access modes: %s", strerror(-r
));
386 return PAM_SESSION_ERR
;
392 static int reset_group(
393 pam_handle_t
*handle
,
394 const char *controller
) {
400 if ((r
= cg_attach(controller
, "/", 0)) < 0) {
401 pam_syslog(handle
, LOG_ERR
, "Failed to reset cgroup for controller %s: %s", controller
, strerror(-r
));
402 return PAM_SESSION_ERR
;
408 _public_ PAM_EXTERN
int pam_sm_open_session(
409 pam_handle_t
*handle
,
411 int argc
, const char **argv
) {
413 const char *username
= NULL
;
418 bool create_session
= true;
420 char **controllers
= NULL
, **reset_controllers
= NULL
, **c
;
421 char *cgroup_user_tree
= NULL
;
425 /* pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing"); */
427 /* Make this a NOP on non-systemd systems */
428 if (sd_booted() <= 0)
431 if (parse_argv(handle
,
433 &create_session
, NULL
, NULL
,
434 &controllers
, &reset_controllers
,
435 NULL
, NULL
, &debug
) < 0)
436 return PAM_SESSION_ERR
;
438 if ((r
= get_user_data(handle
, &username
, &pw
)) != PAM_SUCCESS
)
441 if ((r
= cg_get_user_path(&cgroup_user_tree
)) < 0) {
442 pam_syslog(handle
, LOG_ERR
, "Failed to determine user cgroup tree: %s", strerror(-r
));
447 if (safe_mkdir(RUNTIME_DIR
"/user", 0755, 0, 0) < 0) {
448 pam_syslog(handle
, LOG_ERR
, "Failed to create runtime directory: %m");
453 if ((lock_fd
= open_file_and_lock(RUNTIME_DIR
"/user/.pam-systemd-lock")) < 0) {
454 pam_syslog(handle
, LOG_ERR
, "Failed to lock runtime directory: %m");
459 /* Create /run/user/$USER */
461 if (asprintf(&buf
, RUNTIME_DIR
"/user/%s", username
) < 0) {
466 if (safe_mkdir(buf
, 0700, pw
->pw_uid
, pw
->pw_gid
) < 0) {
467 pam_syslog(handle
, LOG_WARNING
, "Failed to create runtime directory: %m");
470 } else if ((r
= pam_misc_setenv(handle
, "XDG_RUNTIME_DIR", buf
, 0)) != PAM_SUCCESS
) {
471 pam_syslog(handle
, LOG_ERR
, "Failed to set runtime dir.");
478 if (create_session
) {
481 /* Reuse or create XDG session ID */
482 if (!(id
= pam_getenv(handle
, "XDG_SESSION_ID"))) {
485 if (asprintf(&buf
, "%llux", (unsigned long long) get_session_id(&mode
)) < 0) {
490 /* To avoid id clashes we add the session id
491 * source to our session ids. Note that the
492 * session id source might change during
493 * runtime, because a filesystem became
494 * writable or the system reconfigured. */
496 mode
!= SESSION_ID_AUDIT
? (char) mode
: 0;
498 if ((r
= pam_misc_setenv(handle
, "XDG_SESSION_ID", buf
, 0)) != PAM_SUCCESS
) {
499 pam_syslog(handle
, LOG_ERR
, "Failed to set session id.");
503 if (!(id
= pam_getenv(handle
, "XDG_SESSION_ID"))) {
504 pam_syslog(handle
, LOG_ERR
, "Failed to get session id.");
510 r
= asprintf(&buf
, "%s/%s/%s", cgroup_user_tree
, username
, id
);
512 r
= asprintf(&buf
, "%s/%s/master", cgroup_user_tree
, username
);
520 pam_syslog(handle
, LOG_DEBUG
, "Moving new user session for %s into control group %s.", username
, buf
);
522 if ((r
= create_user_group(handle
, SYSTEMD_CGROUP_CONTROLLER
, buf
, pw
, true, true)) != PAM_SUCCESS
)
525 /* The additional controllers don't really matter, so we
526 * ignore the return value */
527 STRV_FOREACH(c
, controllers
)
528 create_user_group(handle
, *c
, buf
, pw
, true, false);
530 STRV_FOREACH(c
, reset_controllers
)
531 reset_group(handle
, *c
);
539 close_nointr_nofail(lock_fd
);
541 strv_free(controllers
);
542 strv_free(reset_controllers
);
544 free(cgroup_user_tree
);
549 static int session_remains(pam_handle_t
*handle
, const char *user_path
) {
551 bool remains
= false;
555 if ((r
= cg_enumerate_subgroups(SYSTEMD_CGROUP_CONTROLLER
, user_path
, &d
)) < 0)
558 while ((r
= cg_read_subgroup(d
, &subgroup
)) > 0) {
560 remains
= !streq(subgroup
, "master");
575 static bool check_user_lists(
576 pam_handle_t
*handle
,
578 char **kill_only_users
,
579 char **kill_exclude_users
) {
581 const char *name
= NULL
;
587 name
= "root"; /* Avoid obvious NSS requests, to suppress network traffic */
591 if ((pw
= pam_modutil_getpwuid(handle
, uid
)))
595 STRV_FOREACH(l
, kill_exclude_users
) {
598 if (safe_atou32(*l
, &id
) >= 0)
599 if ((uid_t
) id
== uid
)
602 if (name
&& streq(name
, *l
))
606 if (strv_isempty(kill_only_users
))
609 STRV_FOREACH(l
, kill_only_users
) {
612 if (safe_atou32(*l
, &id
) >= 0)
613 if ((uid_t
) id
== uid
)
616 if (name
&& streq(name
, *l
))
623 _public_ PAM_EXTERN
int pam_sm_close_session(
624 pam_handle_t
*handle
,
626 int argc
, const char **argv
) {
628 const char *username
= NULL
;
629 bool kill_session
= false;
630 bool kill_user
= false;
633 char *session_path
= NULL
, *nosession_path
= NULL
, *user_path
= NULL
;
636 const void *created
= NULL
;
637 char **controllers
= NULL
, **c
, **kill_only_users
= NULL
, **kill_exclude_users
= NULL
;
638 char *cgroup_user_tree
= NULL
;
642 /* Make this a NOP on non-systemd systems */
643 if (sd_booted() <= 0)
646 if (parse_argv(handle
,
648 NULL
, &kill_session
, &kill_user
,
650 &kill_only_users
, &kill_exclude_users
, &debug
) < 0)
651 return PAM_SESSION_ERR
;
653 if ((r
= get_user_data(handle
, &username
, &pw
)) != PAM_SUCCESS
)
656 if ((r
= cg_get_user_path(&cgroup_user_tree
)) < 0) {
657 pam_syslog(handle
, LOG_ERR
, "Failed to determine user cgroup tree: %s", strerror(-r
));
662 if ((lock_fd
= open_file_and_lock(RUNTIME_DIR
"/user/.pam-systemd-lock")) < 0) {
663 pam_syslog(handle
, LOG_ERR
, "Failed to lock runtime directory: %m");
668 /* We are probably still in some session/user dir. Move ourselves out of the way as first step */
669 if ((r
= cg_attach(SYSTEMD_CGROUP_CONTROLLER
, cgroup_user_tree
, 0)) < 0)
670 pam_syslog(handle
, LOG_ERR
, "Failed to move us away: %s", strerror(-r
));
672 STRV_FOREACH(c
, controllers
)
673 if ((r
= cg_attach(*c
, cgroup_user_tree
, 0)) < 0)
674 pam_syslog(handle
, LOG_ERR
, "Failed to move us away in %s hierarchy: %s", *c
, strerror(-r
));
676 if (asprintf(&user_path
, "%s/%s", cgroup_user_tree
, username
) < 0) {
681 pam_get_data(handle
, "systemd.created", &created
);
683 if ((id
= pam_getenv(handle
, "XDG_SESSION_ID")) && created
) {
685 if (asprintf(&session_path
, "%s/%s/%s", cgroup_user_tree
, username
, id
) < 0 ||
686 asprintf(&nosession_path
, "%s/%s/master", cgroup_user_tree
, username
) < 0) {
691 if (kill_session
&& check_user_lists(handle
, pw
->pw_uid
, kill_only_users
, kill_exclude_users
)) {
693 pam_syslog(handle
, LOG_DEBUG
, "Killing remaining processes of user session %s of %s.", id
, username
);
695 /* Kill processes in session cgroup, and delete it */
696 if ((r
= cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER
, session_path
, true)) < 0)
697 pam_syslog(handle
, LOG_ERR
, "Failed to kill session cgroup: %s", strerror(-r
));
700 pam_syslog(handle
, LOG_DEBUG
, "Moving remaining processes of user session %s of %s into control group %s.", id
, username
, nosession_path
);
702 /* Migrate processes from session to user
703 * cgroup. First, try to create the user group
704 * in case it doesn't exist yet. Also, delete
705 * the session group. */
706 create_user_group(handle
, SYSTEMD_CGROUP_CONTROLLER
, nosession_path
, pw
, false, false);
708 if ((r
= cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER
, session_path
, nosession_path
, false, true)) < 0)
709 pam_syslog(handle
, LOG_ERR
, "Failed to migrate session cgroup: %s", strerror(-r
));
712 STRV_FOREACH(c
, controllers
) {
713 create_user_group(handle
, *c
, nosession_path
, pw
, false, false);
715 if ((r
= cg_migrate_recursive(*c
, session_path
, nosession_path
, false, true)) < 0)
716 pam_syslog(handle
, LOG_ERR
, "Failed to migrate session cgroup in hierarchy %s: %s", *c
, strerror(-r
));
721 cg_trim(SYSTEMD_CGROUP_CONTROLLER
, user_path
, false);
723 if ((r
= session_remains(handle
, user_path
)) < 0)
724 pam_syslog(handle
, LOG_ERR
, "Failed to determine whether a session remains: %s", strerror(-r
));
726 /* Kill user processes not attached to any session */
727 if (kill_user
&& r
== 0 && check_user_lists(handle
, pw
->pw_uid
, kill_only_users
, kill_exclude_users
)) {
729 /* Kill user cgroup */
730 if ((r
= cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER
, user_path
, true)) < 0)
731 pam_syslog(handle
, LOG_ERR
, "Failed to kill user cgroup: %s", strerror(-r
));
734 if ((r
= cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER
, user_path
, true)) < 0)
735 pam_syslog(handle
, LOG_ERR
, "Failed to check user cgroup: %s", strerror(-r
));
737 /* Remove user cgroup */
739 if ((r
= cg_delete(SYSTEMD_CGROUP_CONTROLLER
, user_path
)) < 0)
740 pam_syslog(handle
, LOG_ERR
, "Failed to delete user cgroup: %s", strerror(-r
));
742 /* If we managed to find somebody, don't cleanup the cgroup. */
747 STRV_FOREACH(c
, controllers
)
748 cg_trim(*c
, user_path
, true);
751 const char *runtime_dir
;
753 if ((runtime_dir
= pam_getenv(handle
, "XDG_RUNTIME_DIR")))
754 if ((r
= rm_rf(runtime_dir
, false, true)) < 0)
755 pam_syslog(handle
, LOG_ERR
, "Failed to remove runtime directory: %s", strerror(-r
));
758 /* pam_syslog(handle, LOG_DEBUG, "pam-systemd done"); */
764 close_nointr_nofail(lock_fd
);
767 free(nosession_path
);
770 strv_free(controllers
);
771 strv_free(kill_exclude_users
);
772 strv_free(kill_only_users
);
774 free(cgroup_user_tree
);