1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3 #include <endian.h>
4 #include <errno.h>
5 #include <fcntl.h>
6 #include <pwd.h>
7 #include <security/_pam_macros.h>
8 #include <security/pam_ext.h>
9 #include <security/pam_misc.h>
10 #include <security/pam_modules.h>
11 #include <security/pam_modutil.h>
12 #include <sys/file.h>
13 #include <sys/stat.h>
14 #include <sys/sysmacros.h>
15 #include <sys/types.h>
16 #include <unistd.h>
17
18 #include "alloc-util.h"
19 #include "audit-util.h"
20 #include "bus-common-errors.h"
21 #include "bus-error.h"
22 #include "bus-internal.h"
23 #include "bus-locator.h"
24 #include "cgroup-setup.h"
25 #include "errno-util.h"
26 #include "fd-util.h"
27 #include "fileio.h"
28 #include "format-util.h"
29 #include "fs-util.h"
30 #include "hostname-util.h"
31 #include "locale-util.h"
32 #include "login-util.h"
33 #include "macro.h"
34 #include "pam-util.h"
35 #include "parse-util.h"
36 #include "path-util.h"
37 #include "percent-util.h"
38 #include "process-util.h"
39 #include "rlimit-util.h"
40 #include "socket-util.h"
41 #include "stdio-util.h"
42 #include "strv.h"
43 #include "terminal-util.h"
44 #include "user-util.h"
45 #include "userdb.h"
46
47 #define LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC (2*USEC_PER_MINUTE)
48
parse_argv(pam_handle_t * handle,int argc,const char ** argv,const char ** class,const char ** type,const char ** desktop,bool * debug)49 static int parse_argv(
50 pam_handle_t *handle,
51 int argc, const char **argv,
52 const char **class,
53 const char **type,
54 const char **desktop,
55 bool *debug) {
56
57 unsigned i;
58
59 assert(argc >= 0);
60 assert(argc == 0 || argv);
61
62 for (i = 0; i < (unsigned) argc; i++) {
63 const char *p;
64
65 if ((p = startswith(argv[i], "class="))) {
66 if (class)
67 *class = p;
68
69 } else if ((p = startswith(argv[i], "type="))) {
70 if (type)
71 *type = p;
72
73 } else if ((p = startswith(argv[i], "desktop="))) {
74 if (desktop)
75 *desktop = p;
76
77 } else if (streq(argv[i], "debug")) {
78 if (debug)
79 *debug = true;
80
81 } else if ((p = startswith(argv[i], "debug="))) {
82 int k;
83
84 k = parse_boolean(p);
85 if (k < 0)
86 pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring: %s", p);
87 else if (debug)
88 *debug = k;
89
90 } else
91 pam_syslog(handle, LOG_WARNING, "Unknown parameter '%s', ignoring", argv[i]);
92 }
93
94 return 0;
95 }
96
acquire_user_record(pam_handle_t * handle,UserRecord ** ret_record)97 static int acquire_user_record(
98 pam_handle_t *handle,
99 UserRecord **ret_record) {
100
101 _cleanup_(user_record_unrefp) UserRecord *ur = NULL;
102 const char *username = NULL, *json = NULL;
103 _cleanup_free_ char *field = NULL;
104 int r;
105
106 assert(handle);
107
108 r = pam_get_user(handle, &username, NULL);
109 if (r != PAM_SUCCESS) {
110 pam_syslog(handle, LOG_ERR, "Failed to get user name: %s", pam_strerror(handle, r));
111 return r;
112 }
113
114 if (isempty(username)) {
115 pam_syslog(handle, LOG_ERR, "User name not valid.");
116 return PAM_SERVICE_ERR;
117 }
118
119 /* If pam_systemd_homed (or some other module) already acquired the user record we can reuse it
120 * here. */
121 field = strjoin("systemd-user-record-", username);
122 if (!field)
123 return pam_log_oom(handle);
124
125 r = pam_get_data(handle, field, (const void**) &json);
126 if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) {
127 pam_syslog(handle, LOG_ERR, "Failed to get PAM user record data: %s", pam_strerror(handle, r));
128 return r;
129 }
130 if (r == PAM_SUCCESS && json) {
131 _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
132
133 /* Parse cached record */
134 r = json_parse(json, JSON_PARSE_SENSITIVE, &v, NULL, NULL);
135 if (r < 0) {
136 pam_syslog(handle, LOG_ERR, "Failed to parse JSON user record: %s", strerror_safe(r));
137 return PAM_SERVICE_ERR;
138 }
139
140 ur = user_record_new();
141 if (!ur)
142 return pam_log_oom(handle);
143
144 r = user_record_load(ur, v, USER_RECORD_LOAD_REFUSE_SECRET|USER_RECORD_PERMISSIVE);
145 if (r < 0) {
146 pam_syslog(handle, LOG_ERR, "Failed to load user record: %s", strerror_safe(r));
147 return PAM_SERVICE_ERR;
148 }
149
150 /* Safety check if cached record actually matches what we are looking for */
151 if (!streq_ptr(username, ur->user_name)) {
152 pam_syslog(handle, LOG_ERR, "Acquired user record does not match user name.");
153 return PAM_SERVICE_ERR;
154 }
155 } else {
156 _cleanup_free_ char *formatted = NULL;
157
158 /* Request the record ourselves */
159 r = userdb_by_name(username, 0, &ur);
160 if (r < 0) {
161 pam_syslog(handle, LOG_ERR, "Failed to get user record: %s", strerror_safe(r));
162 return PAM_USER_UNKNOWN;
163 }
164
165 r = json_variant_format(ur->json, 0, &formatted);
166 if (r < 0) {
167 pam_syslog(handle, LOG_ERR, "Failed to format user JSON: %s", strerror_safe(r));
168 return PAM_SERVICE_ERR;
169 }
170
171 /* And cache it for everyone else */
172 r = pam_set_data(handle, field, formatted, pam_cleanup_free);
173 if (r < 0) {
174 pam_syslog(handle, LOG_ERR, "Failed to set PAM user record data '%s': %s",
175 field, pam_strerror(handle, r));
176 return r;
177 }
178
179 TAKE_PTR(formatted);
180 }
181
182 if (!uid_is_valid(ur->uid)) {
183 pam_syslog(handle, LOG_ERR, "Acquired user record does not have a UID.");
184 return PAM_SERVICE_ERR;
185 }
186
187 if (ret_record)
188 *ret_record = TAKE_PTR(ur);
189
190 return PAM_SUCCESS;
191 }
192
display_is_local(const char * display)193 static bool display_is_local(const char *display) {
194 assert(display);
195
196 return
197 display[0] == ':' &&
198 display[1] >= '0' &&
199 display[1] <= '9';
200 }
201
socket_from_display(const char * display)202 static int socket_from_display(const char *display) {
203 _cleanup_free_ char *f = NULL;
204 size_t k;
205 char *c;
206 union sockaddr_union sa;
207 socklen_t sa_len;
208 _cleanup_close_ int fd = -1;
209 int r;
210
211 assert(display);
212
213 if (!display_is_local(display))
214 return -EINVAL;
215
216 k = strspn(display+1, "0123456789");
217
218 /* Try abstract socket first. */
219 f = new(char, STRLEN("@/tmp/.X11-unix/X") + k + 1);
220 if (!f)
221 return -ENOMEM;
222
223 c = stpcpy(f, "@/tmp/.X11-unix/X");
224 memcpy(c, display+1, k);
225 c[k] = 0;
226
227 r = sockaddr_un_set_path(&sa.un, f);
228 if (r < 0)
229 return r;
230 sa_len = r;
231
232 fd = RET_NERRNO(socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0));
233 if (fd < 0)
234 return fd;
235
236 r = RET_NERRNO(connect(fd, &sa.sa, sa_len));
237 if (r >= 0)
238 return TAKE_FD(fd);
239 if (r != -ECONNREFUSED)
240 return r;
241
242 /* Try also non-abstract socket. */
243 r = sockaddr_un_set_path(&sa.un, f + 1);
244 if (r < 0)
245 return r;
246 sa_len = r;
247
248 r = RET_NERRNO(connect(fd, &sa.sa, sa_len));
249 if (r >= 0)
250 return TAKE_FD(fd);
251 return r;
252 }
253
get_seat_from_display(const char * display,const char ** seat,uint32_t * vtnr)254 static int get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) {
255 _cleanup_free_ char *sys_path = NULL, *tty = NULL;
256 _cleanup_close_ int fd = -1;
257 struct ucred ucred;
258 int v, r;
259 dev_t display_ctty;
260
261 assert(display);
262 assert(vtnr);
263
264 /* We deduce the X11 socket from the display name, then use
265 * SO_PEERCRED to determine the X11 server process, ask for
266 * the controlling tty of that and if it's a VC then we know
267 * the seat and the virtual terminal. Sounds ugly, is only
268 * semi-ugly. */
269
270 fd = socket_from_display(display);
271 if (fd < 0)
272 return fd;
273
274 r = getpeercred(fd, &ucred);
275 if (r < 0)
276 return r;
277
278 r = get_ctty_devnr(ucred.pid, &display_ctty);
279 if (r < 0)
280 return r;
281
282 if (asprintf(&sys_path, "/sys/dev/char/%d:%d", major(display_ctty), minor(display_ctty)) < 0)
283 return -ENOMEM;
284 r = readlink_value(sys_path, &tty);
285 if (r < 0)
286 return r;
287
288 v = vtnr_from_tty(tty);
289 if (v < 0)
290 return v;
291 else if (v == 0)
292 return -ENOENT;
293
294 if (seat)
295 *seat = "seat0";
296 *vtnr = (uint32_t) v;
297
298 return 0;
299 }
300
export_legacy_dbus_address(pam_handle_t * handle,const char * runtime)301 static int export_legacy_dbus_address(
302 pam_handle_t *handle,
303 const char *runtime) {
304
305 const char *s;
306 _cleanup_free_ char *t = NULL;
307 int r = PAM_BUF_ERR;
308
309 /* We need to export $DBUS_SESSION_BUS_ADDRESS because various applications will not connect
310 * correctly to the bus without it. This setting matches what dbus.socket does for the user
311 * session using 'systemctl --user set-environment'. We want to have the same configuration
312 * in processes started from the PAM session.
313 *
314 * The setting of the address is guarded by the access() check because it is also possible to compile
315 * dbus without --enable-user-session, in which case this socket is not used, and
316 * $DBUS_SESSION_BUS_ADDRESS should not be set. An alternative approach would to not do the access()
317 * check here, and let applications try on their own, by using "unix:path=%s/bus;autolaunch:". But we
318 * expect the socket to be present by the time we do this check, so we can just as well check once
319 * here. */
320
321 s = strjoina(runtime, "/bus");
322 if (access(s, F_OK) < 0)
323 return PAM_SUCCESS;
324
325 if (asprintf(&t, DEFAULT_USER_BUS_ADDRESS_FMT, runtime) < 0)
326 return pam_log_oom(handle);
327
328 r = pam_misc_setenv(handle, "DBUS_SESSION_BUS_ADDRESS", t, 0);
329 if (r != PAM_SUCCESS) {
330 pam_syslog(handle, LOG_ERR, "Failed to set bus variable: %s", pam_strerror(handle, r));
331 return r;
332 }
333
334 return PAM_SUCCESS;
335 }
336
append_session_memory_max(pam_handle_t * handle,sd_bus_message * m,const char * limit)337 static int append_session_memory_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
338 uint64_t val;
339 int r;
340
341 if (isempty(limit))
342 return PAM_SUCCESS;
343
344 if (streq(limit, "infinity")) {
345 r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", UINT64_MAX);
346 if (r < 0)
347 return pam_bus_log_create_error(handle, r);
348
349 return PAM_SUCCESS;
350 }
351
352 r = parse_permyriad(limit);
353 if (r >= 0) {
354 r = sd_bus_message_append(m, "(sv)", "MemoryMaxScale", "u", UINT32_SCALE_FROM_PERMYRIAD(r));
355 if (r < 0)
356 return pam_bus_log_create_error(handle, r);
357
358 return PAM_SUCCESS;
359 }
360
361 r = parse_size(limit, 1024, &val);
362 if (r >= 0) {
363 r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", val);
364 if (r < 0)
365 return pam_bus_log_create_error(handle, r);
366
367 return PAM_SUCCESS;
368 }
369
370 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.memory_max, ignoring: %s", limit);
371 return PAM_SUCCESS;
372 }
373
append_session_runtime_max_sec(pam_handle_t * handle,sd_bus_message * m,const char * limit)374 static int append_session_runtime_max_sec(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
375 usec_t val;
376 int r;
377
378 /* No need to parse "infinity" here, it will be set by default later in scope_init() */
379 if (isempty(limit) || streq(limit, "infinity"))
380 return PAM_SUCCESS;
381
382 r = parse_sec(limit, &val);
383 if (r >= 0) {
384 r = sd_bus_message_append(m, "(sv)", "RuntimeMaxUSec", "t", (uint64_t) val);
385 if (r < 0)
386 return pam_bus_log_create_error(handle, r);
387 } else
388 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.runtime_max_sec: %s, ignoring.", limit);
389
390 return PAM_SUCCESS;
391 }
392
append_session_tasks_max(pam_handle_t * handle,sd_bus_message * m,const char * limit)393 static int append_session_tasks_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
394 uint64_t val;
395 int r;
396
397 /* No need to parse "infinity" here, it will be set unconditionally later in manager_start_scope() */
398 if (isempty(limit) || streq(limit, "infinity"))
399 return PAM_SUCCESS;
400
401 r = safe_atou64(limit, &val);
402 if (r >= 0) {
403 r = sd_bus_message_append(m, "(sv)", "TasksMax", "t", val);
404 if (r < 0)
405 return pam_bus_log_create_error(handle, r);
406 } else
407 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.tasks_max, ignoring: %s", limit);
408
409 return PAM_SUCCESS;
410 }
411
append_session_cg_weight(pam_handle_t * handle,sd_bus_message * m,const char * limit,const char * field)412 static int append_session_cg_weight(pam_handle_t *handle, sd_bus_message *m, const char *limit, const char *field) {
413 uint64_t val;
414 int r;
415
416 if (isempty(limit))
417 return PAM_SUCCESS;
418
419 r = cg_weight_parse(limit, &val);
420 if (r >= 0) {
421 r = sd_bus_message_append(m, "(sv)", field, "t", val);
422 if (r < 0)
423 return pam_bus_log_create_error(handle, r);
424 } else if (streq(field, "CPUWeight"))
425 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.cpu_weight, ignoring: %s", limit);
426 else
427 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.io_weight, ignoring: %s", limit);
428
429 return PAM_SUCCESS;
430 }
431
getenv_harder(pam_handle_t * handle,const char * key,const char * fallback)432 static const char* getenv_harder(pam_handle_t *handle, const char *key, const char *fallback) {
433 const char *v;
434
435 assert(handle);
436 assert(key);
437
438 /* Looks for an environment variable, preferably in the environment block associated with the
439 * specified PAM handle, falling back to the process' block instead. Why check both? Because we want
440 * to permit configuration of session properties from unit files that invoke PAM services, so that
441 * PAM services don't have to be reworked to set systemd-specific properties, but these properties
442 * can still be set from the unit file Environment= block. */
443
444 v = pam_getenv(handle, key);
445 if (!isempty(v))
446 return v;
447
448 /* We use secure_getenv() here, since we might get loaded into su/sudo, which are SUID. Ideally
449 * they'd clean up the environment before invoking foreign code (such as PAM modules), but alas they
450 * currently don't (to be precise, they clean up the environment they pass to their children, but
451 * not their own environ[]). */
452 v = secure_getenv(key);
453 if (!isempty(v))
454 return v;
455
456 return fallback;
457 }
458
update_environment(pam_handle_t * handle,const char * key,const char * value)459 static int update_environment(pam_handle_t *handle, const char *key, const char *value) {
460 int r;
461
462 assert(handle);
463 assert(key);
464
465 /* Updates the environment, but only if there's actually a value set. Also, log about errors */
466
467 if (isempty(value))
468 return PAM_SUCCESS;
469
470 r = pam_misc_setenv(handle, key, value, 0);
471 if (r != PAM_SUCCESS)
472 pam_syslog(handle, LOG_ERR, "Failed to set environment variable %s: %s", key, pam_strerror(handle, r));
473
474 return r;
475 }
476
validate_runtime_directory(pam_handle_t * handle,const char * path,uid_t uid)477 static bool validate_runtime_directory(pam_handle_t *handle, const char *path, uid_t uid) {
478 struct stat st;
479
480 assert(handle);
481 assert(path);
482
483 /* Some extra paranoia: let's not set $XDG_RUNTIME_DIR if the directory we'd set it to isn't actually
484 * set up properly for us. This is supposed to provide a careful safety net for supporting su/sudo
485 * type transitions: in that case the UID changes, but the session and thus the user owning it
486 * doesn't change. Since the $XDG_RUNTIME_DIR lifecycle is bound to the session's user being logged
487 * in at least once we should be particularly careful when setting the environment variable, since
488 * otherwise we might end up setting $XDG_RUNTIME_DIR to some directory owned by the wrong user. */
489
490 if (!path_is_absolute(path)) {
491 pam_syslog(handle, LOG_ERR, "Provided runtime directory '%s' is not absolute.", path);
492 goto fail;
493 }
494
495 if (lstat(path, &st) < 0) {
496 pam_syslog(handle, LOG_ERR, "Failed to stat() runtime directory '%s': %s", path, strerror_safe(errno));
497 goto fail;
498 }
499
500 if (!S_ISDIR(st.st_mode)) {
501 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not actually a directory.", path);
502 goto fail;
503 }
504
505 if (st.st_uid != uid) {
506 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not owned by UID " UID_FMT ", as it should.", path, uid);
507 goto fail;
508 }
509
510 return true;
511
512 fail:
513 pam_syslog(handle, LOG_WARNING, "Not setting $XDG_RUNTIME_DIR, as the directory is not in order.");
514 return false;
515 }
516
pam_putenv_and_log(pam_handle_t * handle,const char * e,bool debug)517 static int pam_putenv_and_log(pam_handle_t *handle, const char *e, bool debug) {
518 int r;
519
520 assert(handle);
521 assert(e);
522
523 r = pam_putenv(handle, e);
524 if (r != PAM_SUCCESS) {
525 pam_syslog(handle, LOG_ERR, "Failed to set PAM environment variable %s: %s", e, pam_strerror(handle, r));
526 return r;
527 }
528
529 if (debug)
530 pam_syslog(handle, LOG_DEBUG, "PAM environment variable %s set based on user record.", e);
531
532 return PAM_SUCCESS;
533 }
534
apply_user_record_settings(pam_handle_t * handle,UserRecord * ur,bool debug)535 static int apply_user_record_settings(pam_handle_t *handle, UserRecord *ur, bool debug) {
536 int r;
537
538 assert(handle);
539 assert(ur);
540
541 if (ur->umask != MODE_INVALID) {
542 umask(ur->umask);
543
544 if (debug)
545 pam_syslog(handle, LOG_DEBUG, "Set user umask to %04o based on user record.", ur->umask);
546 }
547
548 STRV_FOREACH(i, ur->environment) {
549 _cleanup_free_ char *n = NULL;
550 const char *e;
551
552 assert_se(e = strchr(*i, '=')); /* environment was already validated while parsing JSON record, this thus must hold */
553
554 n = strndup(*i, e - *i);
555 if (!n)
556 return pam_log_oom(handle);
557
558 if (pam_getenv(handle, n)) {
559 if (debug)
560 pam_syslog(handle, LOG_DEBUG, "PAM environment variable $%s already set, not changing based on record.", *i);
561 continue;
562 }
563
564 r = pam_putenv_and_log(handle, *i, debug);
565 if (r != PAM_SUCCESS)
566 return r;
567 }
568
569 if (ur->email_address) {
570 if (pam_getenv(handle, "EMAIL")) {
571 if (debug)
572 pam_syslog(handle, LOG_DEBUG, "PAM environment variable $EMAIL already set, not changing based on user record.");
573 } else {
574 _cleanup_free_ char *joined = NULL;
575
576 joined = strjoin("EMAIL=", ur->email_address);
577 if (!joined)
578 return pam_log_oom(handle);
579
580 r = pam_putenv_and_log(handle, joined, debug);
581 if (r != PAM_SUCCESS)
582 return r;
583 }
584 }
585
586 if (ur->time_zone) {
587 if (pam_getenv(handle, "TZ")) {
588 if (debug)
589 pam_syslog(handle, LOG_DEBUG, "PAM environment variable $TZ already set, not changing based on user record.");
590 } else if (!timezone_is_valid(ur->time_zone, LOG_DEBUG)) {
591 if (debug)
592 pam_syslog(handle, LOG_DEBUG, "Time zone specified in user record is not valid locally, not setting $TZ.");
593 } else {
594 _cleanup_free_ char *joined = NULL;
595
596 joined = strjoin("TZ=:", ur->time_zone);
597 if (!joined)
598 return pam_log_oom(handle);
599
600 r = pam_putenv_and_log(handle, joined, debug);
601 if (r != PAM_SUCCESS)
602 return r;
603 }
604 }
605
606 if (ur->preferred_language) {
607 if (pam_getenv(handle, "LANG")) {
608 if (debug)
609 pam_syslog(handle, LOG_DEBUG, "PAM environment variable $LANG already set, not changing based on user record.");
610 } else if (locale_is_installed(ur->preferred_language) <= 0) {
611 if (debug)
612 pam_syslog(handle, LOG_DEBUG, "Preferred language specified in user record is not valid or not installed, not setting $LANG.");
613 } else {
614 _cleanup_free_ char *joined = NULL;
615
616 joined = strjoin("LANG=", ur->preferred_language);
617 if (!joined)
618 return pam_log_oom(handle);
619
620 r = pam_putenv_and_log(handle, joined, debug);
621 if (r != PAM_SUCCESS)
622 return r;
623 }
624 }
625
626 if (nice_is_valid(ur->nice_level)) {
627 if (nice(ur->nice_level) < 0)
628 pam_syslog(handle, LOG_ERR, "Failed to set nice level to %i, ignoring: %s", ur->nice_level, strerror_safe(errno));
629 else if (debug)
630 pam_syslog(handle, LOG_DEBUG, "Nice level set, based on user record.");
631 }
632
633 for (int rl = 0; rl < _RLIMIT_MAX; rl++) {
634
635 if (!ur->rlimits[rl])
636 continue;
637
638 r = setrlimit_closest(rl, ur->rlimits[rl]);
639 if (r < 0)
640 pam_syslog(handle, LOG_ERR, "Failed to set resource limit %s, ignoring: %s", rlimit_to_string(rl), strerror_safe(r));
641 else if (debug)
642 pam_syslog(handle, LOG_DEBUG, "Resource limit %s set, based on user record.", rlimit_to_string(rl));
643 }
644
645 return PAM_SUCCESS;
646 }
647
configure_runtime_directory(pam_handle_t * handle,UserRecord * ur,const char * rt)648 static int configure_runtime_directory(
649 pam_handle_t *handle,
650 UserRecord *ur,
651 const char *rt) {
652
653 int r;
654
655 assert(handle);
656 assert(ur);
657 assert(rt);
658
659 if (!validate_runtime_directory(handle, rt, ur->uid))
660 return PAM_SUCCESS;
661
662 r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
663 if (r != PAM_SUCCESS) {
664 pam_syslog(handle, LOG_ERR, "Failed to set runtime dir: %s", pam_strerror(handle, r));
665 return r;
666 }
667
668 return export_legacy_dbus_address(handle, rt);
669 }
670
pam_sm_open_session(pam_handle_t * handle,int flags,int argc,const char ** argv)671 _public_ PAM_EXTERN int pam_sm_open_session(
672 pam_handle_t *handle,
673 int flags,
674 int argc, const char **argv) {
675
676 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
677 _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
678 const char
679 *id, *object_path, *runtime_path,
680 *service = NULL,
681 *tty = NULL, *display = NULL,
682 *remote_user = NULL, *remote_host = NULL,
683 *seat = NULL,
684 *type = NULL, *class = NULL,
685 *class_pam = NULL, *type_pam = NULL, *cvtnr = NULL, *desktop = NULL, *desktop_pam = NULL,
686 *memory_max = NULL, *tasks_max = NULL, *cpu_weight = NULL, *io_weight = NULL, *runtime_max_sec = NULL;
687 _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
688 _cleanup_(user_record_unrefp) UserRecord *ur = NULL;
689 int session_fd = -1, existing, r;
690 bool debug = false, remote;
691 uint32_t vtnr = 0;
692 uid_t original_uid;
693
694 assert(handle);
695
696 if (parse_argv(handle,
697 argc, argv,
698 &class_pam,
699 &type_pam,
700 &desktop_pam,
701 &debug) < 0)
702 return PAM_SESSION_ERR;
703
704 if (debug)
705 pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing");
706
707 r = acquire_user_record(handle, &ur);
708 if (r != PAM_SUCCESS)
709 return r;
710
711 /* Make most of this a NOP on non-logind systems */
712 if (!logind_running())
713 goto success;
714
715 /* Make sure we don't enter a loop by talking to
716 * systemd-logind when it is actually waiting for the
717 * background to finish start-up. If the service is
718 * "systemd-user" we simply set XDG_RUNTIME_DIR and
719 * leave. */
720
721 r = pam_get_item(handle, PAM_SERVICE, (const void**) &service);
722 if (!IN_SET(r, PAM_BAD_ITEM, PAM_SUCCESS)) {
723 pam_syslog(handle, LOG_ERR, "Failed to get PAM service: %s", pam_strerror(handle, r));
724 return r;
725 }
726 if (streq_ptr(service, "systemd-user")) {
727 char rt[STRLEN("/run/user/") + DECIMAL_STR_MAX(uid_t)];
728
729 xsprintf(rt, "/run/user/"UID_FMT, ur->uid);
730 r = configure_runtime_directory(handle, ur, rt);
731 if (r != PAM_SUCCESS)
732 return r;
733
734 goto success;
735 }
736
737 /* Otherwise, we ask logind to create a session for us */
738
739 r = pam_get_item(handle, PAM_XDISPLAY, (const void**) &display);
740 if (!IN_SET(r, PAM_BAD_ITEM, PAM_SUCCESS)) {
741 pam_syslog(handle, LOG_ERR, "Failed to get PAM XDISPLAY: %s", pam_strerror(handle, r));
742 return r;
743 }
744 r = pam_get_item(handle, PAM_TTY, (const void**) &tty);
745 if (!IN_SET(r, PAM_BAD_ITEM, PAM_SUCCESS)) {
746 pam_syslog(handle, LOG_ERR, "Failed to get PAM TTY: %s", pam_strerror(handle, r));
747 return r;
748 }
749 r = pam_get_item(handle, PAM_RUSER, (const void**) &remote_user);
750 if (!IN_SET(r, PAM_BAD_ITEM, PAM_SUCCESS)) {
751 pam_syslog(handle, LOG_ERR, "Failed to get PAM RUSER: %s", pam_strerror(handle, r));
752 return r;
753 }
754 r = pam_get_item(handle, PAM_RHOST, (const void**) &remote_host);
755 if (!IN_SET(r, PAM_BAD_ITEM, PAM_SUCCESS)) {
756 pam_syslog(handle, LOG_ERR, "Failed to get PAM RHOST: %s", pam_strerror(handle, r));
757 return r;
758 }
759
760 seat = getenv_harder(handle, "XDG_SEAT", NULL);
761 cvtnr = getenv_harder(handle, "XDG_VTNR", NULL);
762 type = getenv_harder(handle, "XDG_SESSION_TYPE", type_pam);
763 class = getenv_harder(handle, "XDG_SESSION_CLASS", class_pam);
764 desktop = getenv_harder(handle, "XDG_SESSION_DESKTOP", desktop_pam);
765
766 tty = strempty(tty);
767
768 if (strchr(tty, ':')) {
769 /* A tty with a colon is usually an X11 display, placed there to show up in utmp. We rearrange things
770 * and don't pretend that an X display was a tty. */
771 if (isempty(display))
772 display = tty;
773 tty = NULL;
774
775 } else if (streq(tty, "cron")) {
776 /* cron is setting PAM_TTY to "cron" for some reason (the commit carries no information why, but
777 * probably because it wants to set it to something as pam_time/pam_access/… require PAM_TTY to be set
778 * (as they otherwise even try to update it!) — but cron doesn't actually allocate a TTY for its forked
779 * off processes.) */
780 type = "unspecified";
781 class = "background";
782 tty = NULL;
783
784 } else if (streq(tty, "ssh")) {
785 /* ssh has been setting PAM_TTY to "ssh" (for the same reason as cron does this, see above. For further
786 * details look for "PAM_TTY_KLUDGE" in the openssh sources). */
787 type ="tty";
788 class = "user";
789 tty = NULL; /* This one is particularly sad, as this means that ssh sessions — even though usually
790 * associated with a pty — won't be tracked by their tty in logind. This is because ssh
791 * does the PAM session registration early for new connections, and registers a pty only
792 * much later (this is because it doesn't know yet if it needs one at all, as whether to
793 * register a pty or not is negotiated much later in the protocol). */
794
795 } else
796 /* Chop off leading /dev prefix that some clients specify, but others do not. */
797 tty = skip_dev_prefix(tty);
798
799 /* If this fails vtnr will be 0, that's intended */
800 if (!isempty(cvtnr))
801 (void) safe_atou32(cvtnr, &vtnr);
802
803 if (!isempty(display) && !vtnr) {
804 if (isempty(seat))
805 (void) get_seat_from_display(display, &seat, &vtnr);
806 else if (streq(seat, "seat0"))
807 (void) get_seat_from_display(display, NULL, &vtnr);
808 }
809
810 if (seat && !streq(seat, "seat0") && vtnr != 0) {
811 if (debug)
812 pam_syslog(handle, LOG_DEBUG, "Ignoring vtnr %"PRIu32" for %s which is not seat0", vtnr, seat);
813 vtnr = 0;
814 }
815
816 if (isempty(type))
817 type = !isempty(display) ? "x11" :
818 !isempty(tty) ? "tty" : "unspecified";
819
820 if (isempty(class))
821 class = streq(type, "unspecified") ? "background" : "user";
822
823 remote = !isempty(remote_host) && !is_localhost(remote_host);
824
825 r = pam_get_data(handle, "systemd.memory_max", (const void **)&memory_max);
826 if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) {
827 pam_syslog(handle, LOG_ERR, "Failed to get PAM systemd.memory_max data: %s", pam_strerror(handle, r));
828 return r;
829 }
830 r = pam_get_data(handle, "systemd.tasks_max", (const void **)&tasks_max);
831 if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) {
832 pam_syslog(handle, LOG_ERR, "Failed to get PAM systemd.tasks_max data: %s", pam_strerror(handle, r));
833 return r;
834 }
835 r = pam_get_data(handle, "systemd.cpu_weight", (const void **)&cpu_weight);
836 if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) {
837 pam_syslog(handle, LOG_ERR, "Failed to get PAM systemd.cpu_weight data: %s", pam_strerror(handle, r));
838 return r;
839 }
840 r = pam_get_data(handle, "systemd.io_weight", (const void **)&io_weight);
841 if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) {
842 pam_syslog(handle, LOG_ERR, "Failed to get PAM systemd.io_weight data: %s", pam_strerror(handle, r));
843 return r;
844 }
845 r = pam_get_data(handle, "systemd.runtime_max_sec", (const void **)&runtime_max_sec);
846 if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) {
847 pam_syslog(handle, LOG_ERR, "Failed to get PAM systemd.runtime_max_sec data: %s", pam_strerror(handle, r));
848 return r;
849 }
850
851 /* Talk to logind over the message bus */
852
853 r = pam_acquire_bus_connection(handle, &bus);
854 if (r != PAM_SUCCESS)
855 return r;
856
857 if (debug) {
858 pam_syslog(handle, LOG_DEBUG, "Asking logind to create session: "
859 "uid="UID_FMT" pid="PID_FMT" service=%s type=%s class=%s desktop=%s seat=%s vtnr=%"PRIu32" tty=%s display=%s remote=%s remote_user=%s remote_host=%s",
860 ur->uid, getpid_cached(),
861 strempty(service),
862 type, class, strempty(desktop),
863 strempty(seat), vtnr, strempty(tty), strempty(display),
864 yes_no(remote), strempty(remote_user), strempty(remote_host));
865 pam_syslog(handle, LOG_DEBUG, "Session limits: "
866 "memory_max=%s tasks_max=%s cpu_weight=%s io_weight=%s runtime_max_sec=%s",
867 strna(memory_max), strna(tasks_max), strna(cpu_weight), strna(io_weight), strna(runtime_max_sec));
868 }
869
870 r = bus_message_new_method_call(bus, &m, bus_login_mgr, "CreateSession");
871 if (r < 0)
872 return pam_bus_log_create_error(handle, r);
873
874 r = sd_bus_message_append(m, "uusssssussbss",
875 (uint32_t) ur->uid,
876 0,
877 service,
878 type,
879 class,
880 desktop,
881 seat,
882 vtnr,
883 tty,
884 display,
885 remote,
886 remote_user,
887 remote_host);
888 if (r < 0)
889 return pam_bus_log_create_error(handle, r);
890
891 r = sd_bus_message_open_container(m, 'a', "(sv)");
892 if (r < 0)
893 return pam_bus_log_create_error(handle, r);
894
895 r = append_session_memory_max(handle, m, memory_max);
896 if (r != PAM_SUCCESS)
897 return r;
898
899 r = append_session_runtime_max_sec(handle, m, runtime_max_sec);
900 if (r != PAM_SUCCESS)
901 return r;
902
903 r = append_session_tasks_max(handle, m, tasks_max);
904 if (r != PAM_SUCCESS)
905 return r;
906
907 r = append_session_cg_weight(handle, m, cpu_weight, "CPUWeight");
908 if (r != PAM_SUCCESS)
909 return r;
910
911 r = append_session_cg_weight(handle, m, io_weight, "IOWeight");
912 if (r != PAM_SUCCESS)
913 return r;
914
915 r = sd_bus_message_close_container(m);
916 if (r < 0)
917 return pam_bus_log_create_error(handle, r);
918
919 r = sd_bus_call(bus, m, LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC, &error, &reply);
920 if (r < 0) {
921 if (sd_bus_error_has_name(&error, BUS_ERROR_SESSION_BUSY)) {
922 if (debug)
923 pam_syslog(handle, LOG_DEBUG, "Not creating session: %s", bus_error_message(&error, r));
924
925 /* We are already in a session, don't do anything */
926 goto success;
927 } else {
928 pam_syslog(handle, LOG_ERR, "Failed to create session: %s", bus_error_message(&error, r));
929 return PAM_SESSION_ERR;
930 }
931 }
932
933 r = sd_bus_message_read(reply,
934 "soshusub",
935 &id,
936 &object_path,
937 &runtime_path,
938 &session_fd,
939 &original_uid,
940 &seat,
941 &vtnr,
942 &existing);
943 if (r < 0)
944 return pam_bus_log_parse_error(handle, r);
945
946 if (debug)
947 pam_syslog(handle, LOG_DEBUG, "Reply from logind: "
948 "id=%s object_path=%s runtime_path=%s session_fd=%d seat=%s vtnr=%u original_uid=%u",
949 id, object_path, runtime_path, session_fd, seat, vtnr, original_uid);
950
951 r = update_environment(handle, "XDG_SESSION_ID", id);
952 if (r != PAM_SUCCESS)
953 return r;
954
955 if (original_uid == ur->uid) {
956 /* Don't set $XDG_RUNTIME_DIR if the user we now authenticated for does not match the
957 * original user of the session. We do this in order not to result in privileged apps
958 * clobbering the runtime directory unnecessarily. */
959
960 r = configure_runtime_directory(handle, ur, runtime_path);
961 if (r != PAM_SUCCESS)
962 return r;
963 }
964
965 /* Most likely we got the session/type/class from environment variables, but might have gotten the data
966 * somewhere else (for example PAM module parameters). Let's now update the environment variables, so that this
967 * data is inherited into the session processes, and programs can rely on them to be initialized. */
968
969 r = update_environment(handle, "XDG_SESSION_TYPE", type);
970 if (r != PAM_SUCCESS)
971 return r;
972
973 r = update_environment(handle, "XDG_SESSION_CLASS", class);
974 if (r != PAM_SUCCESS)
975 return r;
976
977 r = update_environment(handle, "XDG_SESSION_DESKTOP", desktop);
978 if (r != PAM_SUCCESS)
979 return r;
980
981 r = update_environment(handle, "XDG_SEAT", seat);
982 if (r != PAM_SUCCESS)
983 return r;
984
985 if (vtnr > 0) {
986 char buf[DECIMAL_STR_MAX(vtnr)];
987 sprintf(buf, "%u", vtnr);
988
989 r = update_environment(handle, "XDG_VTNR", buf);
990 if (r != PAM_SUCCESS)
991 return r;
992 }
993
994 r = pam_set_data(handle, "systemd.existing", INT_TO_PTR(!!existing), NULL);
995 if (r != PAM_SUCCESS) {
996 pam_syslog(handle, LOG_ERR, "Failed to install existing flag: %s", pam_strerror(handle, r));
997 return r;
998 }
999
1000 if (session_fd >= 0) {
1001 session_fd = fcntl(session_fd, F_DUPFD_CLOEXEC, 3);
1002 if (session_fd < 0) {
1003 pam_syslog(handle, LOG_ERR, "Failed to dup session fd: %m");
1004 return PAM_SESSION_ERR;
1005 }
1006
1007 r = pam_set_data(handle, "systemd.session-fd", FD_TO_PTR(session_fd), NULL);
1008 if (r != PAM_SUCCESS) {
1009 pam_syslog(handle, LOG_ERR, "Failed to install session fd: %s", pam_strerror(handle, r));
1010 safe_close(session_fd);
1011 return r;
1012 }
1013 }
1014
1015 success:
1016 r = apply_user_record_settings(handle, ur, debug);
1017 if (r != PAM_SUCCESS)
1018 return r;
1019
1020 /* Let's release the D-Bus connection, after all the session might live quite a long time, and we are
1021 * not going to use the bus connection in that time, so let's better close before the daemon kicks us
1022 * off because we are not processing anything. */
1023 (void) pam_release_bus_connection(handle);
1024 return PAM_SUCCESS;
1025 }
1026
pam_sm_close_session(pam_handle_t * handle,int flags,int argc,const char ** argv)1027 _public_ PAM_EXTERN int pam_sm_close_session(
1028 pam_handle_t *handle,
1029 int flags,
1030 int argc, const char **argv) {
1031
1032 const void *existing = NULL;
1033 bool debug = false;
1034 const char *id;
1035 int r;
1036
1037 assert(handle);
1038
1039 if (parse_argv(handle,
1040 argc, argv,
1041 NULL,
1042 NULL,
1043 NULL,
1044 &debug) < 0)
1045 return PAM_SESSION_ERR;
1046
1047 if (debug)
1048 pam_syslog(handle, LOG_DEBUG, "pam-systemd shutting down");
1049
1050 /* Only release session if it wasn't pre-existing when we
1051 * tried to create it */
1052 r = pam_get_data(handle, "systemd.existing", &existing);
1053 if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) {
1054 pam_syslog(handle, LOG_ERR, "Failed to get PAM systemd.existing data: %s", pam_strerror(handle, r));
1055 return r;
1056 }
1057
1058 id = pam_getenv(handle, "XDG_SESSION_ID");
1059 if (id && !existing) {
1060 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
1061 _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
1062
1063 /* Before we go and close the FIFO we need to tell logind that this is a clean session
1064 * shutdown, so that it doesn't just go and slaughter us immediately after closing the fd */
1065
1066 r = pam_acquire_bus_connection(handle, &bus);
1067 if (r != PAM_SUCCESS)
1068 return r;
1069
1070 r = bus_call_method(bus, bus_login_mgr, "ReleaseSession", &error, NULL, "s", id);
1071 if (r < 0) {
1072 pam_syslog(handle, LOG_ERR, "Failed to release session: %s", bus_error_message(&error, r));
1073 return PAM_SESSION_ERR;
1074 }
1075 }
1076
1077 /* Note that we are knowingly leaking the FIFO fd here. This way, logind can watch us die. If we
1078 * closed it here it would not have any clue when that is completed. Given that one cannot really
1079 * have multiple PAM sessions open from the same process this means we will leak one FD at max. */
1080
1081 return PAM_SUCCESS;
1082 }
1083