src/login/pam_systemd.c

   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 "cap-list.h"
  25 #include "capability-util.h"
  26 #include "cgroup-setup.h"
  27 #include "devnum-util.h"
  28 #include "errno-util.h"
  29 #include "fd-util.h"
  30 #include "fileio.h"
  31 #include "format-util.h"
  32 #include "fs-util.h"
  33 #include "hostname-util.h"
  34 #include "locale-util.h"
  35 #include "login-util.h"
  36 #include "macro.h"
  37 #include "missing_syscall.h"
  38 #include "pam-util.h"
  39 #include "parse-util.h"
  40 #include "path-util.h"
  41 #include "percent-util.h"
  42 #include "process-util.h"
  43 #include "rlimit-util.h"
  44 #include "socket-util.h"
  45 #include "stdio-util.h"
  46 #include "strv.h"
  47 #include "terminal-util.h"
  48 #include "user-util.h"
  49 #include "userdb.h"
  50
  51 #define LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC (2*USEC_PER_MINUTE)
  52
  53 static int parse_caps(
  54                 pam_handle_t *handle,
  55                 const char *value,
  56                 uint64_t *caps) {
  57
  58         bool subtract;
  59         int r;
  60
  61         assert(handle);
  62         assert(value);
  63
  64         if (value[0] == '~') {
  65                 subtract = true;
  66                 value++;
  67         } else
  68                 subtract = false;
  69
  70         for (;;) {
  71                 _cleanup_free_ char *s = NULL;
  72                 uint64_t b, m;
  73                 int c;
  74
  75                 /* We can't use spaces as separators here, as PAM's simplistic argument parser doesn't allow
  76                  * spaces inside of arguments. We use commas instead (which is similar to cap_from_text(),
  77                  * which also uses commas). */
  78                 r = extract_first_word(&value, &s, ",", EXTRACT_DONT_COALESCE_SEPARATORS);
  79                 if (r < 0)
  80                         return r;
  81                 if (r == 0)
  82                         break;
  83
  84                 c = capability_from_name(s);
  85                 if (c < 0) {
  86                         pam_syslog(handle, LOG_WARNING, "Unknown capability, ignoring: %s", s);
  87                         continue;
  88                 }
  89
  90                 m = UINT64_C(1) << c;
  91
  92                 if (!caps)
  93                         continue;
  94
  95                 if (*caps == UINT64_MAX)
  96                         b = subtract ? all_capabilities() : 0;
  97                 else
  98                         b = *caps;
  99
 100                 if (subtract)
 101                         *caps = b & ~m;
 102                 else
 103                         *caps = b | m;
 104         }
 105
 106         return 0;
 107 }
 108
 109 static int parse_argv(
 110                 pam_handle_t *handle,
 111                 int argc, const char **argv,
 112                 const char **class,
 113                 const char **type,
 114                 const char **desktop,
 115                 bool *debug,
 116                 uint64_t *default_capability_bounding_set,
 117                 uint64_t *default_capability_ambient_set) {
 118
 119         int r;
 120
 121         assert(handle);
 122         assert(argc >= 0);
 123         assert(argc == 0 || argv);
 124
 125         for (int i = 0; i < argc; i++) {
 126                 const char *p;
 127
 128                 if ((p = startswith(argv[i], "class="))) {
 129                         if (class)
 130                                 *class = p;
 131
 132                 } else if ((p = startswith(argv[i], "type="))) {
 133                         if (type)
 134                                 *type = p;
 135
 136                 } else if ((p = startswith(argv[i], "desktop="))) {
 137                         if (desktop)
 138                                 *desktop = p;
 139
 140                 } else if (streq(argv[i], "debug")) {
 141                         if (debug)
 142                                 *debug = true;
 143
 144                 } else if ((p = startswith(argv[i], "debug="))) {
 145                         r = parse_boolean(p);
 146                         if (r < 0)
 147                                 pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring: %s", p);
 148                         else if (debug)
 149                                 *debug = r;
 150
 151                 } else if ((p = startswith(argv[i], "default-capability-bounding-set="))) {
 152                         r = parse_caps(handle, p, default_capability_bounding_set);
 153                         if (r < 0)
 154                                 pam_syslog(handle, LOG_WARNING, "Failed to parse default-capability-bounding-set= argument, ignoring: %s", p);
 155
 156                 } else if ((p = startswith(argv[i], "default-capability-ambient-set="))) {
 157                         r = parse_caps(handle, p, default_capability_ambient_set);
 158                         if (r < 0)
 159                                 pam_syslog(handle, LOG_WARNING, "Failed to parse default-capability-ambient-set= argument, ignoring: %s", p);
 160
 161                 } else
 162                         pam_syslog(handle, LOG_WARNING, "Unknown parameter '%s', ignoring.", argv[i]);
 163         }
 164
 165         return 0;
 166 }
 167
 168 static int acquire_user_record(
 169                 pam_handle_t *handle,
 170                 UserRecord **ret_record) {
 171
 172         _cleanup_(user_record_unrefp) UserRecord *ur = NULL;
 173         const char *username = NULL, *json = NULL;
 174         _cleanup_free_ char *field = NULL;
 175         int r;
 176
 177         assert(handle);
 178
 179         r = pam_get_user(handle, &username, NULL);
 180         if (r != PAM_SUCCESS)
 181                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get user name: @PAMERR@");
 182
 183         if (isempty(username))
 184                 return pam_syslog_pam_error(handle, LOG_ERR, PAM_SERVICE_ERR, "User name not valid.");
 185
 186         /* If pam_systemd_homed (or some other module) already acquired the user record we can reuse it
 187          * here. */
 188         field = strjoin("systemd-user-record-", username);
 189         if (!field)
 190                 return pam_log_oom(handle);
 191
 192         r = pam_get_data(handle, field, (const void**) &json);
 193         if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA))
 194                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM user record data: @PAMERR@");
 195         if (r == PAM_SUCCESS && json) {
 196                 _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
 197
 198                 /* Parse cached record */
 199                 r = json_parse(json, JSON_PARSE_SENSITIVE, &v, NULL, NULL);
 200                 if (r < 0)
 201                         return pam_syslog_errno(handle, LOG_ERR, r, "Failed to parse JSON user record: %m");
 202
 203                 ur = user_record_new();
 204                 if (!ur)
 205                         return pam_log_oom(handle);
 206
 207                 r = user_record_load(ur, v, USER_RECORD_LOAD_REFUSE_SECRET|USER_RECORD_PERMISSIVE);
 208                 if (r < 0)
 209                         return pam_syslog_errno(handle, LOG_ERR, r, "Failed to load user record: %m");
 210
 211                 /* Safety check if cached record actually matches what we are looking for */
 212                 if (!streq_ptr(username, ur->user_name))
 213                         return pam_syslog_pam_error(handle, LOG_ERR, PAM_SERVICE_ERR,
 214                                                     "Acquired user record does not match user name.");
 215         } else {
 216                 _cleanup_free_ char *formatted = NULL;
 217
 218                 /* Request the record ourselves */
 219                 r = userdb_by_name(username, 0, &ur);
 220                 if (r < 0) {
 221                         pam_syslog_errno(handle, LOG_ERR, r, "Failed to get user record: %m");
 222                         return PAM_USER_UNKNOWN;
 223                 }
 224
 225                 r = json_variant_format(ur->json, 0, &formatted);
 226                 if (r < 0)
 227                         return pam_syslog_errno(handle, LOG_ERR, r, "Failed to format user JSON: %m");
 228
 229                 /* And cache it for everyone else */
 230                 r = pam_set_data(handle, field, formatted, pam_cleanup_free);
 231                 if (r != PAM_SUCCESS)
 232                         return pam_syslog_pam_error(handle, LOG_ERR, r,
 233                                                     "Failed to set PAM user record data '%s': @PAMERR@", field);
 234                 TAKE_PTR(formatted);
 235         }
 236
 237         if (!uid_is_valid(ur->uid))
 238                 return pam_syslog_pam_error(handle, LOG_ERR, PAM_SERVICE_ERR,
 239                                             "Acquired user record does not have a UID.");
 240
 241         if (ret_record)
 242                 *ret_record = TAKE_PTR(ur);
 243
 244         return PAM_SUCCESS;
 245 }
 246
 247 static bool display_is_local(const char *display) {
 248         assert(display);
 249
 250         return
 251                 display[0] == ':' &&
 252                 ascii_isdigit(display[1]);
 253 }
 254
 255 static int socket_from_display(const char *display) {
 256         _cleanup_free_ char *f = NULL;
 257         size_t k;
 258         char *c;
 259         union sockaddr_union sa;
 260         socklen_t sa_len;
 261         _cleanup_close_ int fd = -EBADF;
 262         int r;
 263
 264         assert(display);
 265
 266         if (!display_is_local(display))
 267                 return -EINVAL;
 268
 269         k = strspn(display+1, "0123456789");
 270
 271         /* Try abstract socket first. */
 272         f = new(char, STRLEN("@/tmp/.X11-unix/X") + k + 1);
 273         if (!f)
 274                 return -ENOMEM;
 275
 276         c = stpcpy(f, "@/tmp/.X11-unix/X");
 277         memcpy(c, display+1, k);
 278         c[k] = 0;
 279
 280         r = sockaddr_un_set_path(&sa.un, f);
 281         if (r < 0)
 282                 return r;
 283         sa_len = r;
 284
 285         fd = RET_NERRNO(socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0));
 286         if (fd < 0)
 287                 return fd;
 288
 289         r = RET_NERRNO(connect(fd, &sa.sa, sa_len));
 290         if (r >= 0)
 291                 return TAKE_FD(fd);
 292         if (r != -ECONNREFUSED)
 293                 return r;
 294
 295         /* Try also non-abstract socket. */
 296         r = sockaddr_un_set_path(&sa.un, f + 1);
 297         if (r < 0)
 298                 return r;
 299         sa_len = r;
 300
 301         r = RET_NERRNO(connect(fd, &sa.sa, sa_len));
 302         if (r >= 0)
 303                 return TAKE_FD(fd);
 304         return r;
 305 }
 306
 307 static int get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) {
 308         _cleanup_free_ char *sys_path = NULL, *tty = NULL;
 309         _cleanup_close_ int fd = -EBADF;
 310         struct ucred ucred;
 311         int v, r;
 312         dev_t display_ctty;
 313
 314         assert(display);
 315         assert(vtnr);
 316
 317         /* We deduce the X11 socket from the display name, then use
 318          * SO_PEERCRED to determine the X11 server process, ask for
 319          * the controlling tty of that and if it's a VC then we know
 320          * the seat and the virtual terminal. Sounds ugly, is only
 321          * semi-ugly. */
 322
 323         fd = socket_from_display(display);
 324         if (fd < 0)
 325                 return fd;
 326
 327         r = getpeercred(fd, &ucred);
 328         if (r < 0)
 329                 return r;
 330
 331         r = get_ctty_devnr(ucred.pid, &display_ctty);
 332         if (r < 0)
 333                 return r;
 334
 335         if (asprintf(&sys_path, "/sys/dev/char/" DEVNUM_FORMAT_STR, DEVNUM_FORMAT_VAL(display_ctty)) < 0)
 336                 return -ENOMEM;
 337         r = readlink_value(sys_path, &tty);
 338         if (r < 0)
 339                 return r;
 340
 341         v = vtnr_from_tty(tty);
 342         if (v < 0)
 343                 return v;
 344         else if (v == 0)
 345                 return -ENOENT;
 346
 347         if (seat)
 348                 *seat = "seat0";
 349         *vtnr = (uint32_t) v;
 350
 351         return 0;
 352 }
 353
 354 static int export_legacy_dbus_address(
 355                 pam_handle_t *handle,
 356                 const char *runtime) {
 357
 358         const char *s;
 359         _cleanup_free_ char *t = NULL;
 360         int r = PAM_BUF_ERR;
 361
 362         /* We need to export $DBUS_SESSION_BUS_ADDRESS because various applications will not connect
 363          * correctly to the bus without it. This setting matches what dbus.socket does for the user
 364          * session using 'systemctl --user set-environment'. We want to have the same configuration
 365          * in processes started from the PAM session.
 366          *
 367          * The setting of the address is guarded by the access() check because it is also possible to compile
 368          * dbus without --enable-user-session, in which case this socket is not used, and
 369          * $DBUS_SESSION_BUS_ADDRESS should not be set. An alternative approach would to not do the access()
 370          * check here, and let applications try on their own, by using "unix:path=%s/bus;autolaunch:". But we
 371          * expect the socket to be present by the time we do this check, so we can just as well check once
 372          * here. */
 373
 374         s = strjoina(runtime, "/bus");
 375         if (access(s, F_OK) < 0)
 376                 return PAM_SUCCESS;
 377
 378         if (asprintf(&t, DEFAULT_USER_BUS_ADDRESS_FMT, runtime) < 0)
 379                 return pam_log_oom(handle);
 380
 381         r = pam_misc_setenv(handle, "DBUS_SESSION_BUS_ADDRESS", t, 0);
 382         if (r != PAM_SUCCESS)
 383                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to set bus variable: @PAMERR@");
 384
 385         return PAM_SUCCESS;
 386 }
 387
 388 static int append_session_memory_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 389         uint64_t val;
 390         int r;
 391
 392         if (isempty(limit))
 393                 return PAM_SUCCESS;
 394
 395         if (streq(limit, "infinity")) {
 396                 r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", UINT64_MAX);
 397                 if (r < 0)
 398                         return pam_bus_log_create_error(handle, r);
 399
 400                 return PAM_SUCCESS;
 401         }
 402
 403         r = parse_permyriad(limit);
 404         if (r >= 0) {
 405                 r = sd_bus_message_append(m, "(sv)", "MemoryMaxScale", "u", UINT32_SCALE_FROM_PERMYRIAD(r));
 406                 if (r < 0)
 407                         return pam_bus_log_create_error(handle, r);
 408
 409                 return PAM_SUCCESS;
 410         }
 411
 412         r = parse_size(limit, 1024, &val);
 413         if (r >= 0) {
 414                 r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", val);
 415                 if (r < 0)
 416                         return pam_bus_log_create_error(handle, r);
 417
 418                 return PAM_SUCCESS;
 419         }
 420
 421         pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.memory_max, ignoring: %s", limit);
 422         return PAM_SUCCESS;
 423 }
 424
 425 static int append_session_runtime_max_sec(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 426         usec_t val;
 427         int r;
 428
 429         /* No need to parse "infinity" here, it will be set by default later in scope_init() */
 430         if (isempty(limit) || streq(limit, "infinity"))
 431                 return PAM_SUCCESS;
 432
 433         r = parse_sec(limit, &val);
 434         if (r >= 0) {
 435                 r = sd_bus_message_append(m, "(sv)", "RuntimeMaxUSec", "t", (uint64_t) val);
 436                 if (r < 0)
 437                         return pam_bus_log_create_error(handle, r);
 438         } else
 439                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.runtime_max_sec: %s, ignoring.", limit);
 440
 441         return PAM_SUCCESS;
 442 }
 443
 444 static int append_session_tasks_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 445         uint64_t val;
 446         int r;
 447
 448         /* No need to parse "infinity" here, it will be set unconditionally later in manager_start_scope() */
 449         if (isempty(limit) || streq(limit, "infinity"))
 450                 return PAM_SUCCESS;
 451
 452         r = safe_atou64(limit, &val);
 453         if (r >= 0) {
 454                 r = sd_bus_message_append(m, "(sv)", "TasksMax", "t", val);
 455                 if (r < 0)
 456                         return pam_bus_log_create_error(handle, r);
 457         } else
 458                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.tasks_max, ignoring: %s", limit);
 459
 460         return PAM_SUCCESS;
 461 }
 462
 463 static int append_session_cpu_weight(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 464         uint64_t val;
 465         int r;
 466
 467         if (isempty(limit))
 468                 return PAM_SUCCESS;
 469
 470         r = cg_cpu_weight_parse(limit, &val);
 471         if (r < 0)
 472                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.cpu_weight, ignoring: %s", limit);
 473         else {
 474                 r = sd_bus_message_append(m, "(sv)", "CPUWeight", "t", val);
 475                 if (r < 0)
 476                         return pam_bus_log_create_error(handle, r);
 477         }
 478
 479         return PAM_SUCCESS;
 480 }
 481
 482 static int append_session_io_weight(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 483         uint64_t val;
 484         int r;
 485
 486         if (isempty(limit))
 487                 return PAM_SUCCESS;
 488
 489         r = cg_weight_parse(limit, &val);
 490         if (r < 0)
 491                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.io_weight, ignoring: %s", limit);
 492         else {
 493                 r = sd_bus_message_append(m, "(sv)", "IOWeight", "t", val);
 494                 if (r < 0)
 495                         return pam_bus_log_create_error(handle, r);
 496         }
 497
 498         return PAM_SUCCESS;
 499 }
 500
 501 static const char* getenv_harder(pam_handle_t *handle, const char *key, const char *fallback) {
 502         const char *v;
 503
 504         assert(handle);
 505         assert(key);
 506
 507         /* Looks for an environment variable, preferably in the environment block associated with the
 508          * specified PAM handle, falling back to the process' block instead. Why check both? Because we want
 509          * to permit configuration of session properties from unit files that invoke PAM services, so that
 510          * PAM services don't have to be reworked to set systemd-specific properties, but these properties
 511          * can still be set from the unit file Environment= block. */
 512
 513         v = pam_getenv(handle, key);
 514         if (!isempty(v))
 515                 return v;
 516
 517         /* We use secure_getenv() here, since we might get loaded into su/sudo, which are SUID. Ideally
 518          * they'd clean up the environment before invoking foreign code (such as PAM modules), but alas they
 519          * currently don't (to be precise, they clean up the environment they pass to their children, but
 520          * not their own environ[]). */
 521         v = secure_getenv(key);
 522         if (!isempty(v))
 523                 return v;
 524
 525         return fallback;
 526 }
 527
 528 static bool getenv_harder_bool(pam_handle_t *handle, const char *key, bool fallback) {
 529         const char *v;
 530         int r;
 531
 532         assert(handle);
 533         assert(key);
 534
 535         v = getenv_harder(handle, key, NULL);
 536         if (isempty(v))
 537                 return fallback;
 538
 539         r = parse_boolean(v);
 540         if (r < 0) {
 541                 pam_syslog(handle, LOG_ERR, "Boolean environment variable value of '%s' is not valid: %s", key, v);
 542                 return fallback;
 543         }
 544
 545         return r;
 546 }
 547
 548 static int update_environment(pam_handle_t *handle, const char *key, const char *value) {
 549         int r;
 550
 551         assert(handle);
 552         assert(key);
 553
 554         /* Updates the environment, but only if there's actually a value set. Also, log about errors */
 555
 556         if (isempty(value))
 557                 return PAM_SUCCESS;
 558
 559         r = pam_misc_setenv(handle, key, value, 0);
 560         if (r != PAM_SUCCESS)
 561                 return pam_syslog_pam_error(handle, LOG_ERR, r,
 562                                             "Failed to set environment variable %s: @PAMERR@", key);
 563
 564         return PAM_SUCCESS;
 565 }
 566
 567 static bool validate_runtime_directory(pam_handle_t *handle, const char *path, uid_t uid) {
 568         struct stat st;
 569
 570         assert(handle);
 571         assert(path);
 572
 573         /* Some extra paranoia: let's not set $XDG_RUNTIME_DIR if the directory we'd set it to isn't actually
 574          * set up properly for us. This is supposed to provide a careful safety net for supporting su/sudo
 575          * type transitions: in that case the UID changes, but the session and thus the user owning it
 576          * doesn't change. Since the $XDG_RUNTIME_DIR lifecycle is bound to the session's user being logged
 577          * in at least once we should be particularly careful when setting the environment variable, since
 578          * otherwise we might end up setting $XDG_RUNTIME_DIR to some directory owned by the wrong user. */
 579
 580         if (!path_is_absolute(path)) {
 581                 pam_syslog(handle, LOG_ERR, "Provided runtime directory '%s' is not absolute.", path);
 582                 goto fail;
 583         }
 584
 585         if (lstat(path, &st) < 0) {
 586                 pam_syslog_errno(handle, LOG_ERR, errno, "Failed to stat() runtime directory '%s': %m", path);
 587                 goto fail;
 588         }
 589
 590         if (!S_ISDIR(st.st_mode)) {
 591                 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not actually a directory.", path);
 592                 goto fail;
 593         }
 594
 595         if (st.st_uid != uid) {
 596                 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not owned by UID " UID_FMT ", as it should.", path, uid);
 597                 goto fail;
 598         }
 599
 600         return true;
 601
 602 fail:
 603         pam_syslog(handle, LOG_WARNING, "Not setting $XDG_RUNTIME_DIR, as the directory is not in order.");
 604         return false;
 605 }
 606
 607 static int pam_putenv_and_log(pam_handle_t *handle, const char *e, bool debug) {
 608         int r;
 609
 610         assert(handle);
 611         assert(e);
 612
 613         r = pam_putenv(handle, e);
 614         if (r != PAM_SUCCESS)
 615                 return pam_syslog_pam_error(handle, LOG_ERR, r,
 616                                             "Failed to set PAM environment variable %s: @PAMERR@", e);
 617
 618         pam_debug_syslog(handle, debug, "PAM environment variable %s set based on user record.", e);
 619
 620         return PAM_SUCCESS;
 621 }
 622
 623 static int apply_user_record_settings(
 624                 pam_handle_t *handle,
 625                 UserRecord *ur,
 626                 bool debug,
 627                 uint64_t default_capability_bounding_set,
 628                 uint64_t default_capability_ambient_set) {
 629         _cleanup_strv_free_ char **langs = NULL;
 630         int r;
 631
 632         assert(handle);
 633         assert(ur);
 634
 635         if (ur->umask != MODE_INVALID) {
 636                 umask(ur->umask);
 637                 pam_debug_syslog(handle, debug, "Set user umask to %04o based on user record.", ur->umask);
 638         }
 639
 640         STRV_FOREACH(i, ur->environment) {
 641                 r = pam_putenv_and_log(handle, *i, debug);
 642                 if (r != PAM_SUCCESS)
 643                         return r;
 644         }
 645
 646         if (ur->email_address) {
 647                 _cleanup_free_ char *joined = NULL;
 648
 649                 joined = strjoin("EMAIL=", ur->email_address);
 650                 if (!joined)
 651                         return pam_log_oom(handle);
 652
 653                 r = pam_putenv_and_log(handle, joined, debug);
 654                 if (r != PAM_SUCCESS)
 655                         return r;
 656         }
 657
 658         if (ur->time_zone) {
 659                 if (!timezone_is_valid(ur->time_zone, LOG_DEBUG))
 660                         pam_debug_syslog(handle, debug,
 661                                          "Time zone specified in user record is not valid locally, not setting $TZ.");
 662                 else {
 663                         _cleanup_free_ char *joined = NULL;
 664
 665                         joined = strjoin("TZ=:", ur->time_zone);
 666                         if (!joined)
 667                                 return pam_log_oom(handle);
 668
 669                         r = pam_putenv_and_log(handle, joined, debug);
 670                         if (r != PAM_SUCCESS)
 671                                 return r;
 672                 }
 673         }
 674
 675         r = user_record_languages(ur, &langs);
 676         if (r < 0)
 677                 pam_syslog_errno(handle, LOG_ERR, r,
 678                                  "Failed to acquire user's language preferences, ignoring: %m");
 679         else if (strv_isempty(langs))
 680                 ; /* User has no preference set so we do nothing */
 681         else if (locale_is_installed(langs[0]) <= 0)
 682                 pam_debug_syslog(handle, debug,
 683                                  "Preferred languages specified in user record are not installed locally, not setting $LANG or $LANGUAGE.");
 684         else {
 685                 _cleanup_free_ char *lang = NULL;
 686
 687                 lang = strjoin("LANG=", langs[0]);
 688                 if (!lang)
 689                         return pam_log_oom(handle);
 690
 691                 r = pam_putenv_and_log(handle, lang, debug);
 692                 if (r != PAM_SUCCESS)
 693                         return r;
 694
 695                 if (strv_length(langs) > 1) {
 696                         _cleanup_free_ char *joined = NULL, *language = NULL;
 697
 698                         joined = strv_join(langs, ":");
 699                         if (!joined)
 700                                 return pam_log_oom(handle);
 701
 702                         language = strjoin("LANGUAGE=", joined);
 703                         if (!language)
 704                                 return pam_log_oom(handle);
 705
 706                         r = pam_putenv_and_log(handle, language, debug);
 707                         if (r != PAM_SUCCESS)
 708                                 return r;
 709                 }
 710         }
 711
 712         if (nice_is_valid(ur->nice_level)) {
 713                 if (nice(ur->nice_level) < 0)
 714                         pam_syslog_errno(handle, LOG_ERR, errno,
 715                                          "Failed to set nice level to %i, ignoring: %m", ur->nice_level);
 716                 else
 717                         pam_debug_syslog(handle, debug,
 718                                          "Nice level set to %i, based on user record.", ur->nice_level);
 719         }
 720
 721         for (int rl = 0; rl < _RLIMIT_MAX; rl++) {
 722
 723                 if (!ur->rlimits[rl])
 724                         continue;
 725
 726                 r = setrlimit_closest(rl, ur->rlimits[rl]);
 727                 if (r < 0)
 728                         pam_syslog_errno(handle, LOG_ERR, r,
 729                                          "Failed to set resource limit %s, ignoring: %m", rlimit_to_string(rl));
 730                 else
 731                         pam_debug_syslog(handle, debug,
 732                                          "Resource limit %s set, based on user record.", rlimit_to_string(rl));
 733         }
 734
 735         uint64_t a, b;
 736         a = user_record_capability_ambient_set(ur);
 737         if (a == UINT64_MAX)
 738                 a = default_capability_ambient_set;
 739
 740         b = user_record_capability_bounding_set(ur);
 741         if (b == UINT64_MAX)
 742                 b = default_capability_bounding_set;
 743
 744         if (a != UINT64_MAX && a != 0) {
 745                 a &= b;
 746
 747                 r = capability_ambient_set_apply(a, /* also_inherit= */ true);
 748                 if (r < 0)
 749                         pam_syslog_errno(handle, LOG_ERR, r,
 750                                          "Failed to set ambient capabilities, ignoring: %m");
 751         }
 752
 753         if (b != UINT64_MAX && !cap_test_all(b)) {
 754                 r = capability_bounding_set_drop(b, /* right_now= */ false);
 755                 if (r < 0)
 756                         pam_syslog_errno(handle, LOG_ERR, r,
 757                                          "Failed to set bounding capabilities, ignoring: %m");
 758         }
 759
 760         return PAM_SUCCESS;
 761 }
 762
 763 static int configure_runtime_directory(
 764                 pam_handle_t *handle,
 765                 UserRecord *ur,
 766                 const char *rt) {
 767
 768         int r;
 769
 770         assert(handle);
 771         assert(ur);
 772         assert(rt);
 773
 774         if (!validate_runtime_directory(handle, rt, ur->uid))
 775                 return PAM_SUCCESS;
 776
 777         r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
 778         if (r != PAM_SUCCESS)
 779                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to set runtime dir: @PAMERR@");
 780
 781         return export_legacy_dbus_address(handle, rt);
 782 }
 783
 784 static uint64_t pick_default_capability_ambient_set(
 785                 UserRecord *ur,
 786                 const char *service,
 787                 const char *seat) {
 788
 789         /* If not configured otherwise, let's enable CAP_WAKE_ALARM for regular users when logging in on a
 790          * seat (i.e. when they are present physically on the device), or when invoked for the systemd --user
 791          * instances. This allows desktops to install CAP_WAKE_ALARM to implement alarm clock apps without
 792          * much fuss. */
 793
 794         return ur &&
 795                 user_record_disposition(ur) == USER_REGULAR &&
 796                 (streq_ptr(service, "systemd-user") || !isempty(seat)) ? (UINT64_C(1) << CAP_WAKE_ALARM) : UINT64_MAX;
 797 }
 798
 799 typedef struct SessionContext {
 800         const uid_t uid;
 801         const pid_t pid;
 802         const char *service;
 803         const char *type;
 804         const char *class;
 805         const char *desktop;
 806         const char *seat;
 807         const uint32_t vtnr;
 808         const char *tty;
 809         const char *display;
 810         const bool remote;
 811         const char *remote_user;
 812         const char *remote_host;
 813         const char *memory_max;
 814         const char *tasks_max;
 815         const char *cpu_weight;
 816         const char *io_weight;
 817         const char *runtime_max_sec;
 818 } SessionContext;
 819
 820 static int create_session_message(
 821                 sd_bus *bus,
 822                 pam_handle_t *handle,
 823                 const SessionContext *context,
 824                 bool avoid_pidfd,
 825                 sd_bus_message **ret) {
 826
 827         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
 828         _cleanup_close_ int pidfd = -EBADF;
 829         int r;
 830
 831         assert(bus);
 832         assert(handle);
 833         assert(context);
 834         assert(ret);
 835
 836         if (!avoid_pidfd) {
 837                 pidfd = pidfd_open(getpid_cached(), 0);
 838                 if (pidfd < 0 && !ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno))
 839                         return -errno;
 840         }
 841
 842         r = bus_message_new_method_call(bus, &m, bus_login_mgr, pidfd >= 0 ? "CreateSessionWithPIDFD" : "CreateSession");
 843         if (r < 0)
 844                 return r;
 845
 846         r = sd_bus_message_append(m,
 847                                   pidfd >= 0 ? "uhsssssussbss" : "uusssssussbss",
 848                                   (uint32_t) context->uid,
 849                                   pidfd >= 0 ? pidfd : context->pid,
 850                                   context->service,
 851                                   context->type,
 852                                   context->class,
 853                                   context->desktop,
 854                                   context->seat,
 855                                   context->vtnr,
 856                                   context->tty,
 857                                   context->display,
 858                                   context->remote,
 859                                   context->remote_user,
 860                                   context->remote_host);
 861         if (r < 0)
 862                 return r;
 863
 864         if (pidfd >= 0) {
 865                 r = sd_bus_message_append(m, "t", UINT64_C(0));
 866                 if (r < 0)
 867                         return r;
 868         }
 869
 870         r = sd_bus_message_open_container(m, 'a', "(sv)");
 871         if (r < 0)
 872                 return r;
 873
 874         r = append_session_memory_max(handle, m, context->memory_max);
 875         if (r != PAM_SUCCESS)
 876                 return r;
 877
 878         r = append_session_runtime_max_sec(handle, m, context->runtime_max_sec);
 879         if (r != PAM_SUCCESS)
 880                 return r;
 881
 882         r = append_session_tasks_max(handle, m, context->tasks_max);
 883         if (r != PAM_SUCCESS)
 884                 return r;
 885
 886         r = append_session_cpu_weight(handle, m, context->cpu_weight);
 887         if (r != PAM_SUCCESS)
 888                 return r;
 889
 890         r = append_session_io_weight(handle, m, context->io_weight);
 891         if (r != PAM_SUCCESS)
 892                 return r;
 893
 894         r = sd_bus_message_close_container(m);
 895         if (r < 0)
 896                 return r;
 897
 898         *ret = TAKE_PTR(m);
 899         return 0;
 900 }
 901
 902 _public_ PAM_EXTERN int pam_sm_open_session(
 903                 pam_handle_t *handle,
 904                 int flags,
 905                 int argc, const char **argv) {
 906
 907         /* Let's release the D-Bus connection once this function exits, after all the session might live
 908          * quite a long time, and we are not going to process the bus connection in that time, so let's
 909          * better close before the daemon kicks us off because we are not processing anything. */
 910         _cleanup_(pam_bus_data_disconnectp) PamBusData *d = NULL;
 911         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 912         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
 913         const char
 914                 *id, *object_path, *runtime_path,
 915                 *service = NULL,
 916                 *tty = NULL, *display = NULL,
 917                 *remote_user = NULL, *remote_host = NULL,
 918                 *seat = NULL,
 919                 *type = NULL, *class = NULL,
 920                 *class_pam = NULL, *type_pam = NULL, *cvtnr = NULL, *desktop = NULL, *desktop_pam = NULL,
 921                 *memory_max = NULL, *tasks_max = NULL, *cpu_weight = NULL, *io_weight = NULL, *runtime_max_sec = NULL;
 922         uint64_t default_capability_bounding_set = UINT64_MAX, default_capability_ambient_set = UINT64_MAX;
 923         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
 924         _cleanup_(user_record_unrefp) UserRecord *ur = NULL;
 925         int session_fd = -EBADF, existing, r;
 926         bool debug = false, remote, incomplete;
 927         uint32_t vtnr = 0;
 928         uid_t original_uid;
 929
 930         assert(handle);
 931
 932         if (parse_argv(handle,
 933                        argc, argv,
 934                        &class_pam,
 935                        &type_pam,
 936                        &desktop_pam,
 937                        &debug,
 938                        &default_capability_bounding_set,
 939                        &default_capability_ambient_set) < 0)
 940                 return PAM_SESSION_ERR;
 941
 942         pam_debug_syslog(handle, debug, "pam-systemd initializing");
 943
 944         r = acquire_user_record(handle, &ur);
 945         if (r != PAM_SUCCESS)
 946                 return r;
 947
 948         /* Make most of this a NOP on non-logind systems */
 949         if (!logind_running())
 950                 goto success;
 951
 952         r = pam_get_item_many(
 953                         handle,
 954                         PAM_SERVICE, &service,
 955                         PAM_XDISPLAY, &display,
 956                         PAM_TTY, &tty,
 957                         PAM_RUSER, &remote_user,
 958                         PAM_RHOST, &remote_host);
 959         if (r != PAM_SUCCESS)
 960                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM items: @PAMERR@");
 961
 962         seat = getenv_harder(handle, "XDG_SEAT", NULL);
 963         cvtnr = getenv_harder(handle, "XDG_VTNR", NULL);
 964         type = getenv_harder(handle, "XDG_SESSION_TYPE", type_pam);
 965         class = getenv_harder(handle, "XDG_SESSION_CLASS", class_pam);
 966         desktop = getenv_harder(handle, "XDG_SESSION_DESKTOP", desktop_pam);
 967         incomplete = getenv_harder_bool(handle, "XDG_SESSION_INCOMPLETE", false);
 968
 969         if (streq_ptr(service, "systemd-user")) {
 970                 /* If we detect that we are running in the "systemd-user" PAM stack, then let's patch the class to
 971                  * 'manager' if not set, simply for robustness reasons. */
 972                 type = "unspecified";
 973                 class = IN_SET(user_record_disposition(ur), USER_INTRINSIC, USER_SYSTEM, USER_DYNAMIC) ?
 974                         "manager-early" : "manager";
 975                 tty = NULL;
 976
 977         } else if (tty && strchr(tty, ':')) {
 978                 /* A tty with a colon is usually an X11 display, placed there to show up in utmp. We rearrange things
 979                  * and don't pretend that an X display was a tty. */
 980                 if (isempty(display))
 981                         display = tty;
 982                 tty = NULL;
 983
 984         } else if (streq_ptr(tty, "cron")) {
 985                 /* cron is setting PAM_TTY to "cron" for some reason (the commit carries no information why, but
 986                  * probably because it wants to set it to something as pam_time/pam_access/… require PAM_TTY to be set
 987                  * (as they otherwise even try to update it!) — but cron doesn't actually allocate a TTY for its forked
 988                  * off processes.) */
 989                 type = "unspecified";
 990                 class = "background";
 991                 tty = NULL;
 992
 993         } else if (streq_ptr(tty, "ssh")) {
 994                 /* ssh has been setting PAM_TTY to "ssh" (for the same reason as cron does this, see above. For further
 995                  * details look for "PAM_TTY_KLUDGE" in the openssh sources). */
 996                 type = "tty";
 997                 class = "user";
 998                 tty = NULL; /* This one is particularly sad, as this means that ssh sessions — even though usually
 999                              * associated with a pty — won't be tracked by their tty in logind. This is because ssh
1000                              * does the PAM session registration early for new connections, and registers a pty only
1001                              * much later (this is because it doesn't know yet if it needs one at all, as whether to
1002                              * register a pty or not is negotiated much later in the protocol). */
1003
1004         } else if (tty)
1005                 /* Chop off leading /dev prefix that some clients specify, but others do not. */
1006                 tty = skip_dev_prefix(tty);
1007
1008         /* If this fails vtnr will be 0, that's intended */
1009         if (!isempty(cvtnr))
1010                 (void) safe_atou32(cvtnr, &vtnr);
1011
1012         if (!isempty(display) && !vtnr) {
1013                 if (isempty(seat))
1014                         (void) get_seat_from_display(display, &seat, &vtnr);
1015                 else if (streq(seat, "seat0"))
1016                         (void) get_seat_from_display(display, NULL, &vtnr);
1017         }
1018
1019         if (seat && !streq(seat, "seat0") && vtnr != 0) {
1020                 pam_debug_syslog(handle, debug, "Ignoring vtnr %"PRIu32" for %s which is not seat0", vtnr, seat);
1021                 vtnr = 0;
1022         }
1023
1024         if (isempty(type))
1025                 type = !isempty(display) ? "x11" :
1026                            !isempty(tty) ? "tty" : "unspecified";
1027
1028         if (isempty(class))
1029                 class = streq(type, "unspecified") ? "background" :
1030                         ((IN_SET(user_record_disposition(ur), USER_INTRINSIC, USER_SYSTEM, USER_DYNAMIC) &&
1031                          streq(type, "tty")) ? "user-early" : "user");
1032
1033         if (incomplete) {
1034                 if (streq(class, "user"))
1035                         class = "user-incomplete";
1036                 else
1037                         pam_syslog_pam_error(handle, LOG_WARNING, 0, "PAM session of class '%s' is incomplete, which is not supported, ignoring.", class);
1038         }
1039
1040         remote = !isempty(remote_host) && !is_localhost(remote_host);
1041
1042         r = pam_get_data(handle, "systemd.memory_max", (const void **)&memory_max);
1043         if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA))
1044                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM systemd.memory_max data: @PAMERR@");
1045         r = pam_get_data(handle, "systemd.tasks_max",  (const void **)&tasks_max);
1046         if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA))
1047                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM systemd.tasks_max data: @PAMERR@");
1048         r = pam_get_data(handle, "systemd.cpu_weight", (const void **)&cpu_weight);
1049         if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA))
1050                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM systemd.cpu_weight data: @PAMERR@");
1051         r = pam_get_data(handle, "systemd.io_weight",  (const void **)&io_weight);
1052         if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA))
1053                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM systemd.io_weight data: @PAMERR@");
1054         r = pam_get_data(handle, "systemd.runtime_max_sec", (const void **)&runtime_max_sec);
1055         if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA))
1056                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM systemd.runtime_max_sec data: @PAMERR@");
1057
1058         /* Talk to logind over the message bus */
1059         r = pam_acquire_bus_connection(handle, "pam-systemd", &bus, &d);
1060         if (r != PAM_SUCCESS)
1061                 return r;
1062
1063         pam_debug_syslog(handle, debug,
1064                          "Asking logind to create session: "
1065                          "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",
1066                          ur->uid, getpid_cached(),
1067                          strempty(service),
1068                          type, class, strempty(desktop),
1069                          strempty(seat), vtnr, strempty(tty), strempty(display),
1070                          yes_no(remote), strempty(remote_user), strempty(remote_host));
1071         pam_debug_syslog(handle, debug,
1072                          "Session limits: "
1073                          "memory_max=%s tasks_max=%s cpu_weight=%s io_weight=%s runtime_max_sec=%s",
1074                          strna(memory_max), strna(tasks_max), strna(cpu_weight), strna(io_weight), strna(runtime_max_sec));
1075
1076         const SessionContext context = {
1077                 .uid = ur->uid,
1078                 .pid = 0,
1079                 .service = service,
1080                 .type = type,
1081                 .class = class,
1082                 .desktop = desktop,
1083                 .seat = seat,
1084                 .vtnr = vtnr,
1085                 .tty = tty,
1086                 .display = display,
1087                 .remote = remote,
1088                 .remote_user = remote_user,
1089                 .remote_host = remote_host,
1090                 .memory_max = memory_max,
1091                 .tasks_max = tasks_max,
1092                 .cpu_weight = cpu_weight,
1093                 .io_weight = io_weight,
1094                 .runtime_max_sec = runtime_max_sec,
1095         };
1096
1097         r = create_session_message(bus,
1098                                    handle,
1099                                    &context,
1100                                    /* avoid_pidfd = */ false,
1101                                    &m);
1102         if (r < 0)
1103                 return pam_bus_log_create_error(handle, r);
1104
1105         r = sd_bus_call(bus, m, LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC, &error, &reply);
1106         if (r < 0 && sd_bus_error_has_name(&error, SD_BUS_ERROR_UNKNOWN_METHOD)) {
1107                 sd_bus_error_free(&error);
1108                 pam_debug_syslog(handle, debug,
1109                                  "CreateSessionWithPIDFD() API is not available, retrying with CreateSession().");
1110
1111                 m = sd_bus_message_unref(m);
1112                 r = create_session_message(bus,
1113                                            handle,
1114                                            &context,
1115                                            /* avoid_pidfd = */ true,
1116                                            &m);
1117                 if (r < 0)
1118                         return pam_bus_log_create_error(handle, r);
1119
1120                 r = sd_bus_call(bus, m, LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC, &error, &reply);
1121         }
1122         if (r < 0) {
1123                 if (sd_bus_error_has_name(&error, BUS_ERROR_SESSION_BUSY)) {
1124                         /* We are already in a session, don't do anything */
1125                         pam_debug_syslog(handle, debug,
1126                                          "Not creating session: %s", bus_error_message(&error, r));
1127                         goto success;
1128                 }
1129
1130                 pam_syslog(handle, LOG_ERR,
1131                            "Failed to create session: %s", bus_error_message(&error, r));
1132                 return PAM_SESSION_ERR;
1133         }
1134
1135         r = sd_bus_message_read(reply,
1136                                 "soshusub",
1137                                 &id,
1138                                 &object_path,
1139                                 &runtime_path,
1140                                 &session_fd,
1141                                 &original_uid,
1142                                 &seat,
1143                                 &vtnr,
1144                                 &existing);
1145         if (r < 0)
1146                 return pam_bus_log_parse_error(handle, r);
1147
1148         pam_debug_syslog(handle, debug,
1149                          "Reply from logind: "
1150                          "id=%s object_path=%s runtime_path=%s session_fd=%d seat=%s vtnr=%u original_uid=%u",
1151                          id, object_path, runtime_path, session_fd, seat, vtnr, original_uid);
1152
1153         /* Please update manager_default_environment() in core/manager.c accordingly if more session envvars
1154          * shall be added. */
1155
1156         r = update_environment(handle, "XDG_SESSION_ID", id);
1157         if (r != PAM_SUCCESS)
1158                 return r;
1159
1160         if (original_uid == ur->uid) {
1161                 /* Don't set $XDG_RUNTIME_DIR if the user we now authenticated for does not match the
1162                  * original user of the session. We do this in order not to result in privileged apps
1163                  * clobbering the runtime directory unnecessarily. */
1164
1165                 r = configure_runtime_directory(handle, ur, runtime_path);
1166                 if (r != PAM_SUCCESS)
1167                         return r;
1168         }
1169
1170         /* Most likely we got the session/type/class from environment variables, but might have gotten the data
1171          * somewhere else (for example PAM module parameters). Let's now update the environment variables, so that this
1172          * data is inherited into the session processes, and programs can rely on them to be initialized. */
1173
1174         r = update_environment(handle, "XDG_SESSION_TYPE", type);
1175         if (r != PAM_SUCCESS)
1176                 return r;
1177
1178         r = update_environment(handle, "XDG_SESSION_CLASS", class);
1179         if (r != PAM_SUCCESS)
1180                 return r;
1181
1182         r = update_environment(handle, "XDG_SESSION_DESKTOP", desktop);
1183         if (r != PAM_SUCCESS)
1184                 return r;
1185
1186         r = update_environment(handle, "XDG_SEAT", seat);
1187         if (r != PAM_SUCCESS)
1188                 return r;
1189
1190         if (vtnr > 0) {
1191                 char buf[DECIMAL_STR_MAX(vtnr)];
1192                 sprintf(buf, "%u", vtnr);
1193
1194                 r = update_environment(handle, "XDG_VTNR", buf);
1195                 if (r != PAM_SUCCESS)
1196                         return r;
1197         }
1198
1199         r = pam_set_data(handle, "systemd.existing", INT_TO_PTR(!!existing), NULL);
1200         if (r != PAM_SUCCESS)
1201                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to install existing flag: @PAMERR@");
1202
1203         if (session_fd >= 0) {
1204                 _cleanup_close_ int fd = fcntl(session_fd, F_DUPFD_CLOEXEC, 3);
1205                 if (fd < 0)
1206                         return pam_syslog_errno(handle, LOG_ERR, errno, "Failed to dup session fd: %m");
1207
1208                 r = pam_set_data(handle, "systemd.session-fd", FD_TO_PTR(fd), NULL);
1209                 if (r != PAM_SUCCESS)
1210                         return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to install session fd: @PAMERR@");
1211                 TAKE_FD(fd);
1212         }
1213
1214 success:
1215         if (default_capability_ambient_set == UINT64_MAX)
1216                 default_capability_ambient_set = pick_default_capability_ambient_set(ur, service, seat);
1217
1218         return apply_user_record_settings(handle, ur, debug, default_capability_bounding_set, default_capability_ambient_set);
1219 }
1220
1221 _public_ PAM_EXTERN int pam_sm_close_session(
1222                 pam_handle_t *handle,
1223                 int flags,
1224                 int argc, const char **argv) {
1225
1226         const void *existing = NULL;
1227         bool debug = false;
1228         const char *id;
1229         int r;
1230
1231         assert(handle);
1232
1233         if (parse_argv(handle,
1234                        argc, argv,
1235                        NULL,
1236                        NULL,
1237                        NULL,
1238                        &debug,
1239                        NULL,
1240                        NULL) < 0)
1241                 return PAM_SESSION_ERR;
1242
1243         pam_debug_syslog(handle, debug, "pam-systemd shutting down");
1244
1245         /* Only release session if it wasn't pre-existing when we
1246          * tried to create it */
1247         r = pam_get_data(handle, "systemd.existing", &existing);
1248         if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA))
1249                 return pam_syslog_pam_error(handle, LOG_ERR, r,
1250                                             "Failed to get PAM systemd.existing data: @PAMERR@");
1251
1252         id = pam_getenv(handle, "XDG_SESSION_ID");
1253         if (id && !existing) {
1254                 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
1255                 _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
1256
1257                 /* Before we go and close the FIFO we need to tell logind that this is a clean session
1258                  * shutdown, so that it doesn't just go and slaughter us immediately after closing the fd */
1259
1260                 r = pam_acquire_bus_connection(handle, "pam-systemd", &bus, NULL);
1261                 if (r != PAM_SUCCESS)
1262                         return r;
1263
1264                 r = bus_call_method(bus, bus_login_mgr, "ReleaseSession", &error, NULL, "s", id);
1265                 if (r < 0)
1266                         return pam_syslog_pam_error(handle, LOG_ERR, PAM_SESSION_ERR,
1267                                                     "Failed to release session: %s", bus_error_message(&error, r));
1268         }
1269
1270         /* Note that we are knowingly leaking the FIFO fd here. This way, logind can watch us die. If we
1271          * closed it here it would not have any clue when that is completed. Given that one cannot really
1272          * have multiple PAM sessions open from the same process this means we will leak one FD at max. */
1273
1274         return PAM_SUCCESS;
1275 }