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"
39 static int parse_argv(pam_handle_t
*handle
,
40 int argc
, const char **argv
,
48 assert(argc
== 0 || argv
);
50 for (i
= 0; i
< (unsigned) argc
; i
++) {
53 if (startswith(argv
[i
], "create-session=")) {
54 if ((k
= parse_boolean(argv
[i
] + 15)) < 0) {
55 pam_syslog(handle
, LOG_ERR
, "Failed to parse create-session= argument.");
61 } else if (startswith(argv
[i
], "kill-session=")) {
62 if ((k
= parse_boolean(argv
[i
] + 13)) < 0) {
63 pam_syslog(handle
, LOG_ERR
, "Failed to parse kill-session= argument.");
70 } else if (startswith(argv
[i
], "kill-user=")) {
71 if ((k
= parse_boolean(argv
[i
] + 10)) < 0) {
72 pam_syslog(handle
, LOG_ERR
, "Failed to parse kill-user= argument.");
79 pam_syslog(handle
, LOG_ERR
, "Unknown parameter '%s'.", argv
[i
]);
84 if (kill_session
&& *kill_session
&& kill_user
)
90 static int open_file_and_lock(const char *fn
) {
95 if ((fd
= open(fn
, O_RDWR
|O_CLOEXEC
|O_NOCTTY
|O_NOFOLLOW
|O_CREAT
, 0600)) < 0)
98 /* The BSD socket semantics are a lot nicer than those of
99 * POSIX locks. Which is why we use flock() here. BSD locking
100 * does not work across NFS which however is not needed here
101 * as the filesystems in question should be local, and only
102 * locally accessible, and most likely even tmpfs. */
104 if (flock(fd
, LOCK_EX
) < 0)
111 SESSION_ID_AUDIT
= 'a',
112 SESSION_ID_COUNTER
= 'c',
113 SESSION_ID_RANDOM
= 'r'
116 static uint64_t get_session_id(int *mode
) {
122 /* First attempt: let's use the session ID of the audit
123 * system, if it is available. */
124 if (read_one_line_file("/proc/self/sessionid", &s
) >= 0) {
128 r
= safe_atou32(s
, &u
);
131 if (r
>= 0 && u
!= (uint32_t) -1 && u
> 0) {
132 *mode
= SESSION_ID_AUDIT
;
137 /* Second attempt, use our own counter. */
138 if ((fd
= open_file_and_lock(RUNTIME_DIR
"/user/.pam-systemd-session")) >= 0) {
142 /* We do a bit of endianess swapping here, just to be
143 * sure. /var should be machine specific anyway, and
144 * /var/run even mounted from tmpfs, so this
145 * byteswapping should really not be necessary. But
146 * then again, you never know, so let's avoid any
149 if (loop_read(fd
, &counter
, sizeof(counter
), false) != sizeof(counter
))
152 counter
= le64toh(counter
) + 1;
154 if (lseek(fd
, 0, SEEK_SET
) == 0) {
155 uint64_t swapped
= htole64(counter
);
157 r
= loop_write(fd
, &swapped
, sizeof(swapped
), false);
159 if (r
!= sizeof(swapped
))
164 close_nointr_nofail(fd
);
167 *mode
= SESSION_ID_COUNTER
;
172 *mode
= SESSION_ID_RANDOM
;
174 /* Last attempt, pick a random value */
175 return (uint64_t) random_ull();
177 static int get_user_data(
178 pam_handle_t
*handle
,
179 const char **ret_username
,
180 struct passwd
**ret_pw
) {
182 const char *username
= NULL
;
183 struct passwd
*pw
= NULL
;
185 bool have_loginuid
= false;
189 assert(ret_username
);
192 if (read_one_line_file("/proc/self/loginuid", &s
) >= 0) {
195 r
= safe_atou32(s
, &u
);
198 if (r
>= 0 && u
!= (uint32_t) -1 && u
> 0) {
199 have_loginuid
= true;
200 pw
= pam_modutil_getpwuid(handle
, u
);
204 if (!have_loginuid
) {
205 if ((r
= pam_get_user(handle
, &username
, NULL
)) != PAM_SUCCESS
) {
206 pam_syslog(handle
, LOG_ERR
, "Failed to get user name.");
210 if (!username
|| !*username
) {
211 pam_syslog(handle
, LOG_ERR
, "User name not valid.");
215 pw
= pam_modutil_getpwnam(handle
, username
);
219 pam_syslog(handle
, LOG_ERR
, "Failed to get user data.");
220 return PAM_USER_UNKNOWN
;
224 *ret_username
= username
? username
: pw
->pw_name
;
229 static int create_user_group(pam_handle_t
*handle
, const char *group
, struct passwd
*pw
, bool attach
, bool remember
) {
236 r
= cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER
, group
, 0);
238 r
= cg_create(SYSTEMD_CGROUP_CONTROLLER
, group
);
241 pam_syslog(handle
, LOG_ERR
, "Failed to create cgroup: %s", strerror(-r
));
242 return PAM_SESSION_ERR
;
245 if (r
> 0 && remember
) {
246 /* Remember that it was us who created this group, and
247 * that hence we need to remove it too. This is a
248 * protection against removing the cgroup when run
250 if ((r
= pam_set_data(handle
, "systemd.created", INT_TO_PTR(1), NULL
)) != PAM_SUCCESS
) {
251 pam_syslog(handle
, LOG_ERR
, "Failed to install created variable.");
256 if ((r
= cg_set_task_access(SYSTEMD_CGROUP_CONTROLLER
, group
, 0755, pw
->pw_uid
, pw
->pw_gid
)) < 0 ||
257 (r
= cg_set_group_access(SYSTEMD_CGROUP_CONTROLLER
, group
, 0755, pw
->pw_uid
, pw
->pw_gid
)) < 0) {
258 pam_syslog(handle
, LOG_ERR
, "Failed to change access modes: %s", strerror(-r
));
259 return PAM_SESSION_ERR
;
265 _public_ PAM_EXTERN
int pam_sm_open_session(
266 pam_handle_t
*handle
,
268 int argc
, const char **argv
) {
270 const char *username
= NULL
;
275 bool create_session
= true;
279 /* pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing"); */
281 if (parse_argv(handle
, argc
, argv
, &create_session
, NULL
, NULL
) < 0)
282 return PAM_SESSION_ERR
;
284 /* Make this a NOP on non-systemd systems */
285 if (sd_booted() <= 0)
288 if ((r
= get_user_data(handle
, &username
, &pw
)) != PAM_SUCCESS
)
291 if (safe_mkdir(RUNTIME_DIR
"/user", 0755, 0, 0) < 0) {
292 pam_syslog(handle
, LOG_ERR
, "Failed to create runtime directory: %m");
297 if ((lock_fd
= open_file_and_lock(RUNTIME_DIR
"/user/.pam-systemd-lock")) < 0) {
298 pam_syslog(handle
, LOG_ERR
, "Failed to lock runtime directory: %m");
303 /* Create /var/run/$USER */
305 if (asprintf(&buf
, RUNTIME_DIR
"/user/%s", username
) < 0) {
310 if (safe_mkdir(buf
, 0700, pw
->pw_uid
, pw
->pw_gid
) < 0) {
311 pam_syslog(handle
, LOG_WARNING
, "Failed to create runtime directory: %m");
314 } else if ((r
= pam_misc_setenv(handle
, "XDG_RUNTIME_DIR", buf
, 0)) != PAM_SUCCESS
) {
315 pam_syslog(handle
, LOG_ERR
, "Failed to set runtime dir.");
322 if (create_session
) {
325 /* Reuse or create XDG session ID */
326 if (!(id
= pam_getenv(handle
, "XDG_SESSION_ID"))) {
329 if (asprintf(&buf
, "%llux", (unsigned long long) get_session_id(&mode
)) < 0) {
334 /* To avoid id clashes we add the session id
335 * source to our session ids. Note that the
336 * session id source might change during
337 * runtime, because a filesystem became
338 * writable or the system reconfigured. */
340 mode
!= SESSION_ID_AUDIT
? (char) mode
: 0;
342 if ((r
= pam_misc_setenv(handle
, "XDG_SESSION_ID", buf
, 0)) != PAM_SUCCESS
) {
343 pam_syslog(handle
, LOG_ERR
, "Failed to set session id.");
347 if (!(id
= pam_getenv(handle
, "XDG_SESSION_ID"))) {
348 pam_syslog(handle
, LOG_ERR
, "Failed to get session id.");
354 r
= asprintf(&buf
, "/user/%s/%s", username
, id
);
356 r
= asprintf(&buf
, "/user/%s/master", username
);
363 pam_syslog(handle
, LOG_INFO
, "Moving new user session for %s into control group %s.", username
, buf
);
365 if ((r
= create_user_group(handle
, buf
, pw
, true, true)) != PAM_SUCCESS
)
374 close_nointr_nofail(lock_fd
);
379 static int session_remains(pam_handle_t
*handle
, const char *user_path
) {
381 bool remains
= false;
385 if ((r
= cg_enumerate_subgroups(SYSTEMD_CGROUP_CONTROLLER
, user_path
, &d
)) < 0)
388 while ((r
= cg_read_subgroup(d
, &subgroup
)) > 0) {
390 remains
= !streq(subgroup
, "master");
405 _public_ PAM_EXTERN
int pam_sm_close_session(
406 pam_handle_t
*handle
,
408 int argc
, const char **argv
) {
410 const char *username
= NULL
;
411 bool kill_session
= false;
412 bool kill_user
= false;
414 char *session_path
= NULL
, *nosession_path
= NULL
, *user_path
= NULL
;
417 const void *created
= NULL
;
421 if (parse_argv(handle
, argc
, argv
, NULL
, &kill_session
, &kill_user
) < 0)
422 return PAM_SESSION_ERR
;
424 /* Make this a NOP on non-systemd systems */
425 if (sd_booted() <= 0)
428 if ((r
= get_user_data(handle
, &username
, &pw
)) != PAM_SUCCESS
)
431 if ((lock_fd
= open_file_and_lock(RUNTIME_DIR
"/user/.pam-systemd-lock")) < 0) {
432 pam_syslog(handle
, LOG_ERR
, "Failed to lock runtime directory: %m");
437 /* We are probably still in some session/user dir. Move ourselves out of the way as first step */
438 if ((r
= cg_attach(SYSTEMD_CGROUP_CONTROLLER
, "/user", 0)) < 0)
439 pam_syslog(handle
, LOG_ERR
, "Failed to move us away: %s", strerror(-r
));
441 if (asprintf(&user_path
, "/user/%s", username
) < 0) {
446 pam_get_data(handle
, "systemd.created", &created
);
448 if ((id
= pam_getenv(handle
, "XDG_SESSION_ID")) && created
) {
450 if (asprintf(&session_path
, "/user/%s/%s", username
, id
) < 0 ||
451 asprintf(&nosession_path
, "/user/%s/master", username
) < 0) {
457 pam_syslog(handle
, LOG_INFO
, "Killing remaining processes of user session %s of %s.", id
, username
);
459 /* Kill processes in session cgroup, and delete it */
460 if ((r
= cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER
, session_path
, true)) < 0)
461 pam_syslog(handle
, LOG_ERR
, "Failed to kill session cgroup: %s", strerror(-r
));
463 pam_syslog(handle
, LOG_INFO
, "Moving remaining processes of user session %s of %s into control group %s.", id
, username
, nosession_path
);
465 /* Migrate processes from session to user
466 * cgroup. First, try to create the user group
467 * in case it doesn't exist yet. Also, delete
468 * the session group. */
469 create_user_group(handle
, nosession_path
, pw
, false, false);
471 if ((r
= cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER
, session_path
, nosession_path
, false, true)) < 0)
472 pam_syslog(handle
, LOG_ERR
, "Failed to migrate session cgroup: %s", strerror(-r
));
477 cg_trim(SYSTEMD_CGROUP_CONTROLLER
, user_path
, false);
479 if ((r
= session_remains(handle
, user_path
)) < 0)
480 pam_syslog(handle
, LOG_ERR
, "Failed to determine whether a session remains: %s", strerror(-r
));
482 /* Kill user processes not attached to any session */
483 if (kill_user
&& r
== 0) {
485 /* Kill user cgroup */
486 if ((r
= cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER
, user_path
, true)) < 0)
487 pam_syslog(handle
, LOG_ERR
, "Failed to kill user cgroup: %s", strerror(-r
));
490 if ((r
= cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER
, user_path
, true)) < 0)
491 pam_syslog(handle
, LOG_ERR
, "Failed to check user cgroup: %s", strerror(-r
));
493 /* Remove user cgroup */
495 if ((r
= cg_delete(SYSTEMD_CGROUP_CONTROLLER
, user_path
)) < 0)
496 pam_syslog(handle
, LOG_ERR
, "Failed to delete user cgroup: %s", strerror(-r
));
498 /* If we managed to find somebody, don't cleanup the cgroup. */
504 const char *runtime_dir
;
506 if ((runtime_dir
= pam_getenv(handle
, "XDG_RUNTIME_DIR")))
507 if ((r
= rm_rf(runtime_dir
, false, true)) < 0)
508 pam_syslog(handle
, LOG_ERR
, "Failed to remove runtime directory: %s", strerror(-r
));
511 /* pam_syslog(handle, LOG_DEBUG, "pam-systemd done"); */
517 close_nointr_nofail(lock_fd
);
520 free(nosession_path
);