src/login/pam_systemd.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <endian.h>
   4 #include <fcntl.h>
   5 #include <pwd.h>
   6 #include <security/_pam_macros.h>
   7 #include <security/pam_ext.h>
   8 #include <security/pam_misc.h>
   9 #include <security/pam_modules.h>
  10 #include <security/pam_modutil.h>
  11 #include <sys/file.h>
  12 #include "time-util.h"
  13 #include <sys/stat.h>
  14 #include <sys/sysmacros.h>
  15 #include <unistd.h>
  16
  17 #include "sd-bus.h"
  18 #include "sd-varlink.h"
  19
  20 #include "alloc-util.h"
  21 #include "bus-common-errors.h"
  22 #include "bus-error.h"
  23 #include "bus-internal.h"
  24 #include "bus-locator.h"
  25 #include "cap-list.h"
  26 #include "capability-util.h"
  27 #include "cgroup-setup.h"
  28 #include "chase.h"
  29 #include "creds-util.h"
  30 #include "devnum-util.h"
  31 #include "errno-util.h"
  32 #include "extract-word.h"
  33 #include "fd-util.h"
  34 #include "format-util.h"
  35 #include "fs-util.h"
  36 #include "hostname-util.h"
  37 #include "io-util.h"
  38 #include "json-util.h"
  39 #include "locale-util.h"
  40 #include "login-util.h"
  41 #include "osc-context.h"
  42 #include "pam-util.h"
  43 #include "parse-util.h"
  44 #include "path-util.h"
  45 #include "percent-util.h"
  46 #include "pidfd-util.h"
  47 #include "pidref.h"
  48 #include "process-util.h"
  49 #include "rlimit-util.h"
  50 #include "socket-util.h"
  51 #include "stdio-util.h"
  52 #include "string-util.h"
  53 #include "strv.h"
  54 #include "terminal-util.h"
  55 #include "tmpfile-util.h"
  56 #include "user-util.h"
  57 #include "userdb.h"
  58
  59 #define LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC (2*USEC_PER_MINUTE)
  60
  61 static int parse_caps(
  62                 pam_handle_t *handle,
  63                 const char *value,
  64                 uint64_t *caps) {
  65
  66         bool subtract;
  67         int r;
  68
  69         assert(handle);
  70         assert(value);
  71
  72         if (value[0] == '~') {
  73                 subtract = true;
  74                 value++;
  75         } else
  76                 subtract = false;
  77
  78         for (;;) {
  79                 _cleanup_free_ char *s = NULL;
  80                 uint64_t b, m;
  81                 int c;
  82
  83                 /* We can't use spaces as separators here, as PAM's simplistic argument parser doesn't allow
  84                  * spaces inside of arguments. We use commas instead (which is similar to cap_from_text(),
  85                  * which also uses commas). */
  86                 r = extract_first_word(&value, &s, ",", EXTRACT_DONT_COALESCE_SEPARATORS);
  87                 if (r < 0)
  88                         return r;
  89                 if (r == 0)
  90                         break;
  91
  92                 c = capability_from_name(s);
  93                 if (c < 0) {
  94                         pam_syslog(handle, LOG_WARNING, "Unknown capability, ignoring: %s", s);
  95                         continue;
  96                 }
  97
  98                 m = UINT64_C(1) << c;
  99
 100                 if (!caps)
 101                         continue;
 102
 103                 if (*caps == UINT64_MAX)
 104                         b = subtract ? all_capabilities() : 0;
 105                 else
 106                         b = *caps;
 107
 108                 if (subtract)
 109                         *caps = b & ~m;
 110                 else
 111                         *caps = b | m;
 112         }
 113
 114         return 0;
 115 }
 116
 117 static int parse_argv(
 118                 pam_handle_t *handle,
 119                 int argc, const char **argv,
 120                 const char **class,
 121                 const char **type,
 122                 const char **desktop,
 123                 const char **area,
 124                 bool *debug,
 125                 uint64_t *default_capability_bounding_set,
 126                 uint64_t *default_capability_ambient_set) {
 127
 128         int r;
 129
 130         assert(handle);
 131         assert(argc >= 0);
 132         assert(argc == 0 || argv);
 133
 134         for (int i = 0; i < argc; i++) {
 135                 const char *p;
 136
 137                 if ((p = startswith(argv[i], "class="))) {
 138                         if (class)
 139                                 *class = p;
 140
 141                 } else if ((p = startswith(argv[i], "type="))) {
 142                         if (type)
 143                                 *type = p;
 144
 145                 } else if ((p = startswith(argv[i], "desktop="))) {
 146                         if (desktop)
 147                                 *desktop = p;
 148
 149                 } else if ((p = startswith(argv[i], "area="))) {
 150
 151                         if (!isempty(p) && !filename_is_valid(p))
 152                                 pam_syslog(handle, LOG_WARNING, "Area name specified among PAM module parameters is not valid, ignoring: %m");
 153                         else if (area)
 154                                 *area = p;
 155
 156                 } else if (streq(argv[i], "debug")) {
 157                         if (debug)
 158                                 *debug = true;
 159
 160                 } else if ((p = startswith(argv[i], "debug="))) {
 161                         r = parse_boolean(p);
 162                         if (r < 0)
 163                                 pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring: %s", p);
 164                         else if (debug)
 165                                 *debug = r;
 166
 167                 } else if ((p = startswith(argv[i], "default-capability-bounding-set="))) {
 168                         r = parse_caps(handle, p, default_capability_bounding_set);
 169                         if (r < 0)
 170                                 pam_syslog(handle, LOG_WARNING, "Failed to parse default-capability-bounding-set= argument, ignoring: %s", p);
 171
 172                 } else if ((p = startswith(argv[i], "default-capability-ambient-set="))) {
 173                         r = parse_caps(handle, p, default_capability_ambient_set);
 174                         if (r < 0)
 175                                 pam_syslog(handle, LOG_WARNING, "Failed to parse default-capability-ambient-set= argument, ignoring: %s", p);
 176
 177                 } else
 178                         pam_syslog(handle, LOG_WARNING, "Unknown parameter '%s', ignoring.", argv[i]);
 179         }
 180
 181         return 0;
 182 }
 183
 184 static int acquire_user_record(
 185                 pam_handle_t *handle,
 186                 UserRecord **ret_record) {
 187
 188         int r;
 189
 190         assert(handle);
 191
 192         const char *username = NULL;
 193         r = pam_get_user(handle, &username, NULL);
 194         if (r != PAM_SUCCESS)
 195                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get user name: @PAMERR@");
 196         if (isempty(username))
 197                 return pam_syslog_pam_error(handle, LOG_ERR, PAM_SERVICE_ERR, "User name not valid.");
 198
 199         /* If pam_systemd_homed (or some other module) already acquired the user record we can reuse it
 200          * here. */
 201         _cleanup_free_ char *field = strjoin("systemd-user-record-", username);
 202         if (!field)
 203                 return pam_log_oom(handle);
 204
 205         _cleanup_(user_record_unrefp) UserRecord *ur = NULL;
 206         const char *json = NULL;
 207         r = pam_get_data(handle, field, (const void**) &json);
 208         if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA))
 209                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM user record data: @PAMERR@");
 210         if (r == PAM_SUCCESS && json) {
 211                 _cleanup_(sd_json_variant_unrefp) sd_json_variant *v = NULL;
 212
 213                 /* Parse cached record */
 214                 r = sd_json_parse(json, SD_JSON_PARSE_SENSITIVE, &v, NULL, NULL);
 215                 if (r < 0)
 216                         return pam_syslog_errno(handle, LOG_ERR, r, "Failed to parse JSON user record: %m");
 217
 218                 ur = user_record_new();
 219                 if (!ur)
 220                         return pam_log_oom(handle);
 221
 222                 r = user_record_load(ur, v, USER_RECORD_LOAD_REFUSE_SECRET|USER_RECORD_PERMISSIVE);
 223                 if (r < 0)
 224                         return pam_syslog_errno(handle, LOG_ERR, r, "Failed to load user record: %m");
 225
 226                 /* Safety check if cached record actually matches what we are looking for */
 227                 if (!user_record_matches_user_name(ur, username))
 228                         return pam_syslog_pam_error(handle, LOG_ERR, PAM_SERVICE_ERR,
 229                                                     "Acquired user record does not match user name.");
 230         } else {
 231                 _cleanup_free_ char *formatted = NULL;
 232
 233                 /* Request the record ourselves */
 234                 r = userdb_by_name(username, /* match= */ NULL, /* flags= */ 0, &ur);
 235                 if (r < 0) {
 236                         pam_syslog_errno(handle, LOG_ERR, r, "Failed to get user record: %m");
 237                         return PAM_USER_UNKNOWN;
 238                 }
 239
 240                 if (!uid_is_valid(ur->uid)) {
 241                         pam_syslog_errno(handle, LOG_ERR, r, "User record of user '%s' has no UID, refusing: %m", username);
 242                         return PAM_USER_UNKNOWN;
 243                 }
 244
 245                 r = sd_json_variant_format(ur->json, 0, &formatted);
 246                 if (r < 0)
 247                         return pam_syslog_errno(handle, LOG_ERR, r, "Failed to format user JSON: %m");
 248
 249                 /* And cache it for everyone else */
 250                 r = pam_set_data(handle, field, formatted, pam_cleanup_free);
 251                 if (r != PAM_SUCCESS)
 252                         return pam_syslog_pam_error(handle, LOG_ERR, r,
 253                                                     "Failed to set PAM user record data '%s': @PAMERR@", field);
 254                 TAKE_PTR(formatted);
 255         }
 256
 257         if (!uid_is_valid(ur->uid))
 258                 return pam_syslog_pam_error(handle, LOG_ERR, PAM_SERVICE_ERR,
 259                                             "Acquired user record does not have a UID.");
 260
 261         if (ret_record)
 262                 *ret_record = TAKE_PTR(ur);
 263
 264         return PAM_SUCCESS;
 265 }
 266
 267 static bool display_is_local(const char *display) {
 268         assert(display);
 269
 270         return
 271                 display[0] == ':' &&
 272                 ascii_isdigit(display[1]);
 273 }
 274
 275 static int socket_from_display(const char *display) {
 276         _cleanup_free_ char *f = NULL;
 277         size_t k;
 278         char *c;
 279         union sockaddr_union sa;
 280         socklen_t sa_len;
 281         _cleanup_close_ int fd = -EBADF;
 282         int r;
 283
 284         assert(display);
 285
 286         if (!display_is_local(display))
 287                 return -EINVAL;
 288
 289         k = strspn(display+1, "0123456789");
 290
 291         /* Try abstract socket first. */
 292         f = new(char, STRLEN("@/tmp/.X11-unix/X") + k + 1);
 293         if (!f)
 294                 return -ENOMEM;
 295
 296         c = stpcpy(f, "@/tmp/.X11-unix/X");
 297         memcpy(c, display+1, k);
 298         c[k] = 0;
 299
 300         r = sockaddr_un_set_path(&sa.un, f);
 301         if (r < 0)
 302                 return r;
 303         sa_len = r;
 304
 305         fd = RET_NERRNO(socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0));
 306         if (fd < 0)
 307                 return fd;
 308
 309         r = RET_NERRNO(connect(fd, &sa.sa, sa_len));
 310         if (r >= 0)
 311                 return TAKE_FD(fd);
 312         if (r != -ECONNREFUSED)
 313                 return r;
 314
 315         /* Try also non-abstract socket. */
 316         r = sockaddr_un_set_path(&sa.un, f + 1);
 317         if (r < 0)
 318                 return r;
 319         sa_len = r;
 320
 321         r = RET_NERRNO(connect(fd, &sa.sa, sa_len));
 322         if (r >= 0)
 323                 return TAKE_FD(fd);
 324         return r;
 325 }
 326
 327 static int get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) {
 328         _cleanup_free_ char *sys_path = NULL, *tty = NULL;
 329         _cleanup_close_ int fd = -EBADF;
 330         struct ucred ucred;
 331         int v, r;
 332         dev_t display_ctty;
 333
 334         assert(display);
 335         assert(vtnr);
 336
 337         /* We deduce the X11 socket from the display name, then use
 338          * SO_PEERCRED to determine the X11 server process, ask for
 339          * the controlling tty of that and if it's a VC then we know
 340          * the seat and the virtual terminal. Sounds ugly, is only
 341          * semi-ugly. */
 342
 343         fd = socket_from_display(display);
 344         if (fd < 0)
 345                 return fd;
 346
 347         r = getpeercred(fd, &ucred);
 348         if (r < 0)
 349                 return r;
 350
 351         r = get_ctty_devnr(ucred.pid, &display_ctty);
 352         if (r < 0)
 353                 return r;
 354
 355         if (asprintf(&sys_path, "/sys/dev/char/" DEVNUM_FORMAT_STR, DEVNUM_FORMAT_VAL(display_ctty)) < 0)
 356                 return -ENOMEM;
 357         r = readlink_value(sys_path, &tty);
 358         if (r < 0)
 359                 return r;
 360
 361         v = vtnr_from_tty(tty);
 362         if (v < 0)
 363                 return v;
 364         assert(v > 0);
 365
 366         if (seat)
 367                 *seat = "seat0";
 368         *vtnr = (uint32_t) v;
 369
 370         return 0;
 371 }
 372
 373 static int export_legacy_dbus_address(
 374                 pam_handle_t *handle,
 375                 const char *runtime) {
 376
 377         int r;
 378
 379         assert(handle);
 380
 381         /* We need to export $DBUS_SESSION_BUS_ADDRESS because various applications will not connect
 382          * correctly to the bus without it. This setting matches what dbus.socket does for the user session
 383          * using 'systemctl --user set-environment'. We want to have the same configuration in processes
 384          * started from the PAM session.
 385          *
 386          * The setting of the address is guarded by the access() check because it is also possible to compile
 387          * dbus without --enable-user-session, in which case this socket is not used, and
 388          * $DBUS_SESSION_BUS_ADDRESS should not be set. An alternative approach would to not do the access()
 389          * check here, and let applications try on their own, by using "unix:path=%s/bus;autolaunch:". But we
 390          * expect the socket to be present by the time we do this check, so we can just as well check once
 391          * here. */
 392
 393         if (!runtime)
 394                 return PAM_SUCCESS;
 395
 396         const char *s = strjoina(runtime, "/bus");
 397         if (access(s, F_OK) < 0)  {
 398                 if (errno != ENOENT)
 399                         pam_syslog_errno(handle, LOG_WARNING, errno, "Failed to check if %s/bus exists, ignoring: %m", runtime);
 400
 401                 return PAM_SUCCESS;
 402         }
 403
 404         _cleanup_free_ char *t = NULL;
 405         if (asprintf(&t, DEFAULT_USER_BUS_ADDRESS_FMT, runtime) < 0)
 406                 return pam_log_oom(handle);
 407
 408         r = pam_misc_setenv(handle, "DBUS_SESSION_BUS_ADDRESS", t, /* readonly= */ false);
 409         if (r != PAM_SUCCESS)
 410                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to set bus variable: @PAMERR@");
 411
 412         return PAM_SUCCESS;
 413 }
 414
 415 static int append_session_memory_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 416         int r;
 417
 418         assert(handle);
 419         assert(m);
 420
 421         if (isempty(limit))
 422                 return 0;
 423
 424         if (streq(limit, "infinity"))
 425                 return sd_bus_message_append(m, "(sv)", "MemoryMax", "t", UINT64_MAX);
 426
 427         r = parse_permyriad(limit);
 428         if (r >= 0)
 429                 return sd_bus_message_append(m, "(sv)", "MemoryMaxScale", "u", UINT32_SCALE_FROM_PERMYRIAD(r));
 430
 431         uint64_t val;
 432         r = parse_size(limit, 1024, &val);
 433         if (r < 0) {
 434                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.memory_max, ignoring: %s", limit);
 435                 return PAM_SUCCESS;
 436         }
 437
 438         return sd_bus_message_append(m, "(sv)", "MemoryMax", "t", val);
 439 }
 440
 441 static int append_session_runtime_max_sec(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 442         int r;
 443
 444         assert(handle);
 445         assert(m);
 446
 447         /* No need to parse "infinity" here, it will be set by default later in scope_init() */
 448         if (isempty(limit) || streq(limit, "infinity"))
 449                 return 0;
 450
 451         usec_t val;
 452         r = parse_sec(limit, &val);
 453         if (r < 0) {
 454                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.runtime_max_sec: %s, ignoring.", limit);
 455                 return 0;
 456         }
 457
 458         return sd_bus_message_append(m, "(sv)", "RuntimeMaxUSec", "t", (uint64_t) val);
 459 }
 460
 461 static int append_session_tasks_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 462         int r;
 463
 464         assert(handle);
 465         assert(m);
 466
 467         /* No need to parse "infinity" here, it will be set unconditionally later in manager_start_scope() */
 468         if (isempty(limit) || streq(limit, "infinity"))
 469                 return 0;
 470
 471         uint64_t val;
 472         r = safe_atou64(limit, &val);
 473         if (r < 0) {
 474                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.tasks_max, ignoring: %s", limit);
 475                 return 0;
 476         }
 477
 478         return sd_bus_message_append(m, "(sv)", "TasksMax", "t", val);
 479 }
 480
 481 static int append_session_cpu_weight(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 482         int r;
 483
 484         assert(handle);
 485         assert(m);
 486
 487         if (isempty(limit))
 488                 return 0;
 489
 490         uint64_t val;
 491         r = cg_cpu_weight_parse(limit, &val);
 492         if (r < 0) {
 493                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.cpu_weight, ignoring: %s", limit);
 494                 return 0;
 495         }
 496
 497         return sd_bus_message_append(m, "(sv)", "CPUWeight", "t", val);
 498 }
 499
 500 static int append_session_io_weight(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 501         int r;
 502
 503         assert(handle);
 504         assert(m);
 505
 506         if (isempty(limit))
 507                 return 0;
 508
 509         uint64_t val;
 510         r = cg_weight_parse(limit, &val);
 511         if (r < 0) {
 512                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.io_weight, ignoring: %s", limit);
 513                 return 0;
 514         }
 515
 516         return sd_bus_message_append(m, "(sv)", "IOWeight", "t", val);
 517 }
 518
 519 static const char* getenv_harder(pam_handle_t *handle, const char *key, const char *fallback) {
 520         const char *v;
 521
 522         assert(handle);
 523         assert(key);
 524
 525         /* Looks for an environment variable, preferably in the environment block associated with the
 526          * specified PAM handle, falling back to the process' block instead. Why check both? Because we want
 527          * to permit configuration of session properties from unit files that invoke PAM services, so that
 528          * PAM services don't have to be reworked to set systemd-specific properties, but these properties
 529          * can still be set from the unit file Environment= block. */
 530
 531         v = pam_getenv(handle, key);
 532         if (!isempty(v))
 533                 return v;
 534
 535         /* We use secure_getenv() here, since we might get loaded into su/sudo, which are SUID. Ideally
 536          * they'd clean up the environment before invoking foreign code (such as PAM modules), but alas they
 537          * currently don't (to be precise, they clean up the environment they pass to their children, but
 538          * not their own environ[]). */
 539         v = secure_getenv(key);
 540         if (!isempty(v))
 541                 return v;
 542
 543         return fallback;
 544 }
 545
 546 static bool getenv_harder_bool(pam_handle_t *handle, const char *key, bool fallback) {
 547         const char *v;
 548         int r;
 549
 550         assert(handle);
 551         assert(key);
 552
 553         v = getenv_harder(handle, key, NULL);
 554         if (isempty(v))
 555                 return fallback;
 556
 557         r = parse_boolean(v);
 558         if (r < 0) {
 559                 pam_syslog(handle, LOG_WARNING, "Failed to parse environment variable value '%s' of '%s', falling back to using '%s'.", v, key, true_false(fallback));
 560                 return fallback;
 561         }
 562
 563         return r;
 564 }
 565
 566 static uint32_t getenv_harder_uint32(pam_handle_t *handle, const char *key, uint32_t fallback) {
 567         int r;
 568
 569         assert(handle);
 570         assert(key);
 571
 572         const char *v = getenv_harder(handle, key, NULL);
 573         if (isempty(v))
 574                 return fallback;
 575
 576         uint32_t u;
 577         r = safe_atou32(v, &u);
 578         if (r < 0) {
 579                 pam_syslog(handle, LOG_WARNING, "Failed to parse environment variable value '%s' of '%s' as unsigned integer, falling back to using %" PRIu32 ".", v, key, fallback);
 580                 return fallback;
 581         }
 582
 583         return u;
 584 }
 585
 586 static int update_environment(pam_handle_t *handle, const char *key, const char *value) {
 587         int r;
 588
 589         assert(handle);
 590         assert(key);
 591
 592         /* Updates the environment, and removes environment variables if value is NULL or empty. Also, log
 593          * about errors. */
 594
 595         if (isempty(value)) {
 596                 /* Unset the variable if set. Note that pam_putenv() would log nastily behind our back if we
 597                  * call it without the variable actually being set. Hence we check explicitly if it's set
 598                  * before. */
 599
 600                 if (!pam_getenv(handle, key))
 601                         return PAM_SUCCESS;
 602
 603                 r = pam_putenv(handle, key);
 604                 if (!IN_SET(r, PAM_SUCCESS, PAM_BAD_ITEM))
 605                         return pam_syslog_pam_error(handle, LOG_WARNING, r,
 606                                                     "Failed to unset %s environment variable: @PAMERR@", key);
 607
 608                 return PAM_SUCCESS;
 609         }
 610
 611         r = pam_misc_setenv(handle, key, value, /* readonly= */ false);
 612         if (r != PAM_SUCCESS)
 613                 return pam_syslog_pam_error(handle, LOG_ERR, r,
 614                                             "Failed to set environment variable %s: @PAMERR@", key);
 615
 616         return PAM_SUCCESS;
 617 }
 618
 619 static int propagate_credential_to_environment(pam_handle_t *handle, const char *credential, const char *varname) {
 620         int r;
 621
 622         assert(handle);
 623         assert(credential);
 624         assert(varname);
 625
 626         _cleanup_free_ char *value = NULL;
 627
 628         /* Read a service credential, and propagate it into an environment variable */
 629
 630         r = read_credential(credential, (void**) &value, /* ret_size= */ NULL);
 631         if (r < 0) {
 632                 log_debug_errno(r, "Failed to read credential '%s', ignoring: %m", credential);
 633                 return PAM_SUCCESS;
 634         }
 635
 636         r = pam_misc_setenv(handle, varname, value, 0);
 637         if (r != PAM_SUCCESS)
 638                 return pam_syslog_pam_error(handle, LOG_ERR, r,
 639                                             "Failed to set environment variable %s: @PAMERR@", varname);
 640
 641         return PAM_SUCCESS;
 642 }
 643
 644 static bool validate_runtime_directory(pam_handle_t *handle, const char *path, uid_t uid) {
 645         struct stat st;
 646
 647         assert(handle);
 648         assert(path);
 649
 650         /* Some extra paranoia: let's not set $XDG_RUNTIME_DIR if the directory we'd set it to isn't actually
 651          * set up properly for us. This is supposed to provide a careful safety net for supporting su/sudo
 652          * type transitions: in that case the UID changes, but the session and thus the user owning it
 653          * doesn't change. Since the $XDG_RUNTIME_DIR lifecycle is bound to the session's user being logged
 654          * in at least once we should be particularly careful when setting the environment variable, since
 655          * otherwise we might end up setting $XDG_RUNTIME_DIR to some directory owned by the wrong user. */
 656
 657         if (!path_is_absolute(path)) {
 658                 pam_syslog(handle, LOG_ERR, "Provided runtime directory '%s' is not absolute.", path);
 659                 goto fail;
 660         }
 661
 662         if (lstat(path, &st) < 0) {
 663                 pam_syslog_errno(handle, LOG_ERR, errno, "Failed to stat() runtime directory '%s': %m", path);
 664                 goto fail;
 665         }
 666
 667         if (!S_ISDIR(st.st_mode)) {
 668                 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not actually a directory.", path);
 669                 goto fail;
 670         }
 671
 672         if (st.st_uid != uid) {
 673                 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not owned by UID " UID_FMT ", as it should.", path, uid);
 674                 goto fail;
 675         }
 676
 677         return true;
 678
 679 fail:
 680         pam_syslog(handle, LOG_WARNING, "Not setting $XDG_RUNTIME_DIR, as the directory is not in order.");
 681         return false;
 682 }
 683
 684 static int pam_putenv_and_log(pam_handle_t *handle, const char *e, bool debug) {
 685         int r;
 686
 687         assert(handle);
 688         assert(e);
 689
 690         r = pam_putenv(handle, e);
 691         if (r != PAM_SUCCESS)
 692                 return pam_syslog_pam_error(handle, LOG_ERR, r,
 693                                             "Failed to set PAM environment variable %s: @PAMERR@", e);
 694
 695         pam_debug_syslog(handle, debug, "PAM environment variable %s set based on user record.", e);
 696
 697         return PAM_SUCCESS;
 698 }
 699
 700 static int apply_user_record_settings(
 701                 pam_handle_t *handle,
 702                 UserRecord *ur,
 703                 bool debug,
 704                 uint64_t default_capability_bounding_set,
 705                 uint64_t default_capability_ambient_set) {
 706         _cleanup_strv_free_ char **langs = NULL;
 707         int r;
 708
 709         assert(handle);
 710         assert(ur);
 711
 712         if (ur->umask != MODE_INVALID) {
 713                 umask(ur->umask);
 714                 pam_debug_syslog(handle, debug, "Set user umask to %04o based on user record.", ur->umask);
 715         }
 716
 717         STRV_FOREACH(i, ur->environment) {
 718                 r = pam_putenv_and_log(handle, *i, debug);
 719                 if (r != PAM_SUCCESS)
 720                         return r;
 721         }
 722
 723         if (ur->email_address) {
 724                 _cleanup_free_ char *joined = NULL;
 725
 726                 joined = strjoin("EMAIL=", ur->email_address);
 727                 if (!joined)
 728                         return pam_log_oom(handle);
 729
 730                 r = pam_putenv_and_log(handle, joined, debug);
 731                 if (r != PAM_SUCCESS)
 732                         return r;
 733         }
 734
 735         if (ur->time_zone) {
 736                 if (!timezone_is_valid(ur->time_zone, LOG_DEBUG))
 737                         pam_debug_syslog(handle, debug,
 738                                          "Time zone specified in user record is not valid locally, not setting $TZ.");
 739                 else {
 740                         _cleanup_free_ char *joined = NULL;
 741
 742                         joined = strjoin("TZ=:", ur->time_zone);
 743                         if (!joined)
 744                                 return pam_log_oom(handle);
 745
 746                         r = pam_putenv_and_log(handle, joined, debug);
 747                         if (r != PAM_SUCCESS)
 748                                 return r;
 749                 }
 750         }
 751
 752         r = user_record_languages(ur, &langs);
 753         if (r < 0)
 754                 pam_syslog_errno(handle, LOG_ERR, r,
 755                                  "Failed to acquire user's language preferences, ignoring: %m");
 756         else if (strv_isempty(langs))
 757                 ; /* User has no preference set so we do nothing */
 758         else if (locale_is_installed(langs[0]) <= 0)
 759                 pam_debug_syslog(handle, debug,
 760                                  "Preferred languages specified in user record are not installed locally, not setting $LANG or $LANGUAGE.");
 761         else {
 762                 _cleanup_free_ char *lang = NULL;
 763
 764                 lang = strjoin("LANG=", langs[0]);
 765                 if (!lang)
 766                         return pam_log_oom(handle);
 767
 768                 r = pam_putenv_and_log(handle, lang, debug);
 769                 if (r != PAM_SUCCESS)
 770                         return r;
 771
 772                 if (strv_length(langs) > 1) {
 773                         _cleanup_free_ char *joined = NULL, *language = NULL;
 774
 775                         joined = strv_join(langs, ":");
 776                         if (!joined)
 777                                 return pam_log_oom(handle);
 778
 779                         language = strjoin("LANGUAGE=", joined);
 780                         if (!language)
 781                                 return pam_log_oom(handle);
 782
 783                         r = pam_putenv_and_log(handle, language, debug);
 784                         if (r != PAM_SUCCESS)
 785                                 return r;
 786                 }
 787         }
 788
 789         if (nice_is_valid(ur->nice_level)) {
 790                 if (nice(ur->nice_level) < 0)
 791                         pam_syslog_errno(handle, LOG_WARNING, errno,
 792                                          "Failed to set nice level to %i, ignoring: %m", ur->nice_level);
 793                 else
 794                         pam_debug_syslog(handle, debug,
 795                                          "Nice level set to %i, based on user record.", ur->nice_level);
 796         }
 797
 798         for (int rl = 0; rl < _RLIMIT_MAX; rl++) {
 799                 if (!ur->rlimits[rl])
 800                         continue;
 801
 802                 r = setrlimit_closest(rl, ur->rlimits[rl]);
 803                 if (r < 0)
 804                         pam_syslog_errno(handle, LOG_ERR, r,
 805                                          "Failed to set resource limit %s, ignoring: %m", rlimit_to_string(rl));
 806                 else
 807                         pam_debug_syslog(handle, debug,
 808                                          "Resource limit %s set, based on user record.", rlimit_to_string(rl));
 809         }
 810
 811         uint64_t a, b;
 812         a = user_record_capability_ambient_set(ur);
 813         if (a == UINT64_MAX)
 814                 a = default_capability_ambient_set;
 815
 816         b = user_record_capability_bounding_set(ur);
 817         if (b == UINT64_MAX)
 818                 b = default_capability_bounding_set;
 819
 820         if (a != UINT64_MAX && a != 0) {
 821                 a &= b;
 822
 823                 r = capability_ambient_set_apply(a, /* also_inherit= */ true);
 824                 if (r < 0)
 825                         pam_syslog_errno(handle, LOG_ERR, r,
 826                                          "Failed to set ambient capabilities, ignoring: %m");
 827         }
 828
 829         if (b != UINT64_MAX && !cap_test_all(b)) {
 830                 r = capability_bounding_set_drop(b, /* right_now= */ false);
 831                 if (r < 0)
 832                         pam_syslog_errno(handle, LOG_ERR, r,
 833                                          "Failed to set bounding capabilities, ignoring: %m");
 834         }
 835
 836         return PAM_SUCCESS;
 837 }
 838
 839 static uint64_t pick_default_capability_ambient_set(
 840                 UserRecord *ur,
 841                 const char *service,
 842                 const char *seat) {
 843
 844         /* If not configured otherwise, let's enable CAP_WAKE_ALARM for regular users when logging in on a
 845          * seat (i.e. when they are present physically on the device), or when invoked for the systemd --user
 846          * instances. This allows desktops to install CAP_WAKE_ALARM to implement alarm clock apps without
 847          * much fuss. */
 848
 849         return ur &&
 850                 user_record_disposition(ur) == USER_REGULAR &&
 851                 (streq_ptr(service, "systemd-user") || !isempty(seat)) ? (UINT64_C(1) << CAP_WAKE_ALARM) : UINT64_MAX;
 852 }
 853
 854 typedef struct SessionContext {
 855         const char *service;
 856         const char *type;
 857         const char *class;
 858         const char *desktop;
 859         const char *seat;
 860         uint32_t vtnr;
 861         const char *tty;
 862         const char *display;
 863         bool remote;
 864         const char *remote_user;
 865         const char *remote_host;
 866         const char *memory_max;
 867         const char *tasks_max;
 868         const char *cpu_weight;
 869         const char *io_weight;
 870         const char *runtime_max_sec;
 871         const char *area;
 872         bool incomplete;
 873 } SessionContext;
 874
 875 static int create_session_message(
 876                 sd_bus *bus,
 877                 pam_handle_t *handle,
 878                 UserRecord *ur,
 879                 const SessionContext *context,
 880                 bool avoid_pidfd,
 881                 sd_bus_message **ret) {
 882
 883         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
 884         _cleanup_close_ int pidfd = -EBADF;
 885         int r;
 886
 887         assert(bus);
 888         assert(handle);
 889         assert(ur);
 890         assert(context);
 891         assert(ret);
 892
 893         if (!avoid_pidfd) {
 894                 pidfd = pidfd_open(getpid_cached(), 0);
 895                 if (pidfd < 0)
 896                         return -errno;
 897         }
 898
 899         r = bus_message_new_method_call(bus, &m, bus_login_mgr, pidfd >= 0 ? "CreateSessionWithPIDFD" : "CreateSession");
 900         if (r < 0)
 901                 return r;
 902
 903         r = sd_bus_message_append(
 904                         m,
 905                         pidfd >= 0 ? "uhsssssussbss" : "uusssssussbss",
 906                         (uint32_t) ur->uid,
 907                         pidfd >= 0 ? pidfd : 0,
 908                         context->service,
 909                         context->type,
 910                         context->class,
 911                         context->desktop,
 912                         context->seat,
 913                         context->vtnr,
 914                         context->tty,
 915                         context->display,
 916                         context->remote,
 917                         context->remote_user,
 918                         context->remote_host);
 919         if (r < 0)
 920                 return r;
 921
 922         if (pidfd >= 0) {
 923                 r = sd_bus_message_append(m, "t", UINT64_C(0));
 924                 if (r < 0)
 925                         return r;
 926         }
 927
 928         r = sd_bus_message_open_container(m, 'a', "(sv)");
 929         if (r < 0)
 930                 return r;
 931
 932         r = append_session_memory_max(handle, m, context->memory_max);
 933         if (r < 0)
 934                 return r;
 935
 936         r = append_session_runtime_max_sec(handle, m, context->runtime_max_sec);
 937         if (r < 0)
 938                 return r;
 939
 940         r = append_session_tasks_max(handle, m, context->tasks_max);
 941         if (r < 0)
 942                 return r;
 943
 944         r = append_session_cpu_weight(handle, m, context->cpu_weight);
 945         if (r < 0)
 946                 return r;
 947
 948         r = append_session_io_weight(handle, m, context->io_weight);
 949         if (r < 0)
 950                 return r;
 951
 952         r = sd_bus_message_close_container(m);
 953         if (r < 0)
 954                 return r;
 955
 956         *ret = TAKE_PTR(m);
 957         return 0;
 958 }
 959
 960 static void session_context_mangle(
 961                 pam_handle_t *handle,
 962                 SessionContext *c,
 963                 UserRecord *ur,
 964                 bool debug) {
 965
 966         assert(handle);
 967         assert(c);
 968         assert(ur);
 969
 970         if (streq_ptr(c->service, "systemd-user")) {
 971                 /* If we detect that we are running in the "systemd-user" PAM stack, then let's patch the class to
 972                  * 'manager' if not set, simply for robustness reasons. */
 973                 c->type = "unspecified";
 974                 c->class = IN_SET(user_record_disposition(ur), USER_INTRINSIC, USER_SYSTEM, USER_DYNAMIC) ?
 975                         "manager-early" : "manager";
 976                 c->tty = NULL;
 977
 978         } else if (c->tty && strchr(c->tty, ':')) {
 979                 /* A tty with a colon is usually an X11 display, placed there to show up in utmp. We rearrange things
 980                  * and don't pretend that an X display was a tty. */
 981                 if (isempty(c->display))
 982                         c->display = c->tty;
 983                 c->tty = NULL;
 984
 985         } else if (streq_ptr(c->tty, "cron")) {
 986                 /* cron is setting PAM_TTY to "cron" for some reason (the commit carries no information why, but
 987                  * probably because it wants to set it to something as pam_time/pam_access/… require PAM_TTY to be set
 988                  * (as they otherwise even try to update it!) — but cron doesn't actually allocate a TTY for its forked
 989                  * off processes.) */
 990                 c->type = "unspecified";
 991                 c->class = "background";
 992                 c->tty = NULL;
 993
 994         } else if (streq_ptr(c->tty, "ssh")) {
 995                 /* ssh has been setting PAM_TTY to "ssh" (for the same reason as cron does this, see above. For further
 996                  * details look for "PAM_TTY_KLUDGE" in the openssh sources). */
 997                 c->type = "tty";
 998                 c->class = "user";
 999                 c->tty = NULL; /* This one is particularly sad, as this means that ssh sessions — even though
1000                                * usually associated with a pty — won't be tracked by their tty in
1001                                * logind. This is because ssh does the PAM session registration early for new
1002                                * connections, and registers a pty only much later (this is because it doesn't
1003                                * know yet if it needs one at all, as whether to register a pty or not is
1004                                * negotiated much later in the protocol). */
1005
1006         } else if (c->tty)
1007                 /* Chop off leading /dev prefix that some clients specify, but others do not. */
1008                 c->tty = skip_dev_prefix(c->tty);
1009
1010         if (!isempty(c->display) && !c->vtnr) {
1011                 if (isempty(c->seat))
1012                         (void) get_seat_from_display(c->display, &c->seat, &c->vtnr);
1013                 else if (streq(c->seat, "seat0"))
1014                         (void) get_seat_from_display(c->display, /* seat= */ NULL, &c->vtnr);
1015         }
1016
1017         if (c->seat && !streq(c->seat, "seat0") && c->vtnr != 0) {
1018                 pam_debug_syslog(handle, debug, "Ignoring vtnr %"PRIu32" for %s which is not seat0", c->vtnr, c->seat);
1019                 c->vtnr = 0;
1020         }
1021
1022         if (isempty(c->type)) {
1023                 c->type = !isempty(c->display) ? "x11" :
1024                               !isempty(c->tty) ? "tty" : "unspecified";
1025                 pam_debug_syslog(handle, debug, "Automatically chose session type '%s'.", c->type);
1026         }
1027
1028         if (!c->area)
1029                 c->area = ur->default_area;
1030
1031         if (!isempty(c->area) && !filename_is_valid(c->area)) {
1032                 pam_syslog(handle, LOG_WARNING, "Specified area '%s' is not a valid filename, ignoring area request.", c->area);
1033                 c->area = NULL;
1034         }
1035
1036         if (isempty(c->class)) {
1037                 c->class = streq(c->type, "unspecified") ? "background" : "user";
1038
1039                 /* For non-regular users tweak the type a bit:
1040                  *
1041                  * - Allow root tty logins *before* systemd-user-sessions.service is run, to allow early boot
1042                  *   logins to debug things.
1043                  *
1044                  * - Non-graphical sessions shall be invoked without service manager.
1045                  *
1046                  * (Note that this somewhat replicates the class mangling logic on systemd-logind.service's
1047                  * server side to some degree, in case clients allocate a session and don't specify a
1048                  * class. This is somewhat redundant, but we need the class set up properly below.)
1049                  *
1050                  * For regular users also tweak the type a bit: if an area is specified at login time, switch
1051                  * to light mode too. (Mostly because at the moment we do no support a per-area service
1052                  * manager. Once we do, we should change this.).
1053                  */
1054
1055                 switch (user_record_disposition(ur)) {
1056
1057                 case USER_INTRINSIC:
1058                 case USER_SYSTEM:
1059                 case USER_DYNAMIC:
1060                         if (streq(c->class, "user"))
1061                                 c->class = user_record_is_root(ur) ? "user-early" :
1062                                         (STR_IN_SET(c->type, "x11", "wayland", "mir") ? "user" : "user-light");
1063                         else if (streq(c->class, "background"))
1064                                 c->class = "background-light";
1065                         break;
1066
1067                 case USER_REGULAR:
1068                         if (!isempty(c->area)) {
1069                                 if (streq(c->class, "user"))
1070                                         c->class = "user-light";
1071                                 else if (streq(c->class, "background"))
1072                                         c->class = "background-light";
1073                         }
1074
1075                         break;
1076
1077                 default:
1078                         ;
1079                 }
1080
1081                 pam_debug_syslog(handle, debug, "Automatically chose session class '%s'.", c->class);
1082         }
1083
1084         if (c->incomplete) {
1085                 if (streq(c->class, "user"))
1086                         c->class = "user-incomplete";
1087                 else
1088                         pam_syslog(handle, LOG_WARNING, "PAM session of class '%s' is incomplete, which is not supported, ignoring.", c->class);
1089         }
1090
1091         c->remote = !isempty(c->remote_host) && !is_localhost(c->remote_host);
1092 }
1093
1094 static bool can_use_varlink(const SessionContext *c) {
1095         /* Since PID 1 currently doesn't do Varlink right now, we cannot directly set properties for the
1096          * scope, for now. */
1097         return !c->memory_max &&
1098                 !c->runtime_max_sec &&
1099                 !c->tasks_max &&
1100                 !c->cpu_weight &&
1101                 !c->io_weight;
1102 }
1103
1104 static int register_session(
1105                 pam_handle_t *handle,
1106                 SessionContext *c,
1107                 UserRecord *ur,
1108                 bool debug,
1109                 char **ret_seat,
1110                 char **ret_type,
1111                 char **ret_runtime_dir) {
1112
1113         int r;
1114
1115         assert(handle);
1116         assert(c);
1117         assert(ur);
1118         assert(ret_seat);
1119         assert(ret_type);
1120         assert(ret_runtime_dir);
1121
1122         /* We don't register session class none with logind */
1123         if (streq(c->class, "none")) {
1124                 pam_debug_syslog(handle, debug, "Skipping logind registration for session class none.");
1125                 *ret_seat = *ret_type = *ret_runtime_dir = NULL;
1126                 return PAM_SUCCESS;
1127         }
1128
1129         /* Make most of this a NOP on non-logind systems */
1130         if (!logind_running()) {
1131                 pam_debug_syslog(handle, debug, "Skipping logind registration as logind is not running.");
1132                 *ret_seat = *ret_type = *ret_runtime_dir = NULL;
1133                 return PAM_SUCCESS;
1134         }
1135
1136         pam_debug_syslog(handle, debug,
1137                          "Asking logind to create session: "
1138                          "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",
1139                          ur->uid, getpid_cached(),
1140                          strempty(c->service),
1141                          c->type, c->class, strempty(c->desktop),
1142                          strempty(c->seat), c->vtnr, strempty(c->tty), strempty(c->display),
1143                          yes_no(c->remote), strempty(c->remote_user), strempty(c->remote_host));
1144         pam_debug_syslog(handle, debug,
1145                          "Session limits: "
1146                          "memory_max=%s tasks_max=%s cpu_weight=%s io_weight=%s runtime_max_sec=%s",
1147                          strna(c->memory_max), strna(c->tasks_max), strna(c->cpu_weight), strna(c->io_weight), strna(c->runtime_max_sec));
1148
1149         _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL; /* the following variables point into this message, hence pin it for longer */
1150         _cleanup_(sd_varlink_unrefp) sd_varlink *vl = NULL; /* similar */
1151         const char *id = NULL, *object_path = NULL, *runtime_path = NULL, *real_seat = NULL;
1152         int existing = false;
1153         uint32_t original_uid = UID_INVALID, real_vtnr = 0;
1154
1155         bool done = false;
1156         if (can_use_varlink(c)) {
1157
1158                 r = sd_varlink_connect_address(&vl, "/run/systemd/io.systemd.Login");
1159                 if (r < 0)
1160                         log_debug_errno(r, "Failed to connect to logind via Varlink, falling back to D-Bus: %m");
1161                 else {
1162                         r = sd_varlink_set_allow_fd_passing_output(vl, true);
1163                         if (r < 0)
1164                                 return pam_syslog_errno(handle, LOG_ERR, r, "Failed to enable output fd passing on Varlink socket: %m");
1165
1166                         r = sd_varlink_set_relative_timeout(vl, LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC);
1167                         if (r < 0)
1168                                 return pam_syslog_errno(handle, LOG_ERR, r, "Failed to set relative timeout on Varlink socket: %m");
1169
1170                         _cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
1171                         r = pidref_set_self(&pidref);
1172                         if (r < 0)
1173                                 return pam_syslog_errno(handle, LOG_ERR, r, "Failed to acquire PID reference on ourselves: %m");
1174
1175                         sd_json_variant *vreply = NULL;
1176                         const char *error_id = NULL;
1177                         r = sd_varlink_callbo(
1178                                         vl,
1179                                         "io.systemd.Login.CreateSession",
1180                                         &vreply,
1181                                         &error_id,
1182                                         SD_JSON_BUILD_PAIR_UNSIGNED("UID", ur->uid),
1183                                         JSON_BUILD_PAIR_PIDREF("PID", &pidref),
1184                                         JSON_BUILD_PAIR_STRING_NON_EMPTY("Service", c->service),
1185                                         SD_JSON_BUILD_PAIR("Type", JSON_BUILD_STRING_UNDERSCORIFY(c->type)),
1186                                         SD_JSON_BUILD_PAIR("Class", JSON_BUILD_STRING_UNDERSCORIFY(c->class)),
1187                                         JSON_BUILD_PAIR_STRING_NON_EMPTY("Desktop", c->desktop),
1188                                         JSON_BUILD_PAIR_STRING_NON_EMPTY("Seat", c->seat),
1189                                         SD_JSON_BUILD_PAIR_CONDITION(c->vtnr > 0, "VTNr", SD_JSON_BUILD_UNSIGNED(c->vtnr)),
1190                                         JSON_BUILD_PAIR_STRING_NON_EMPTY("TTY", c->tty),
1191                                         JSON_BUILD_PAIR_STRING_NON_EMPTY("Display", c->display),
1192                                         SD_JSON_BUILD_PAIR_BOOLEAN("Remote", c->remote),
1193                                         JSON_BUILD_PAIR_STRING_NON_EMPTY("RemoteUser", c->remote_user),
1194                                         JSON_BUILD_PAIR_STRING_NON_EMPTY("RemoteHost", c->remote_host));
1195                         if (r < 0)
1196                                 return pam_syslog_errno(handle, LOG_ERR, r,
1197                                                         "Failed to register session: %s", error_id);
1198                         if (streq_ptr(error_id, "io.systemd.Login.AlreadySessionMember")) {
1199                                 /* We are already in a session, don't do anything */
1200                                 pam_debug_syslog(handle, debug, "Not creating session: %s", error_id);
1201                                 *ret_seat = *ret_type= *ret_runtime_dir = NULL;
1202                                 return PAM_SUCCESS;
1203                         }
1204                         if (error_id)
1205                                 return pam_syslog_errno(handle, LOG_ERR, sd_varlink_error_to_errno(error_id, vreply),
1206                                                         "Failed to issue CreateSession() varlink call: %s", error_id);
1207
1208                         struct {
1209                                 const char *id;
1210                                 const char *runtime_path;
1211                                 uid_t uid;
1212                                 const char *seat;
1213                                 unsigned vtnr;
1214                                 bool existing;
1215                         } p = {
1216                                 .uid = UID_INVALID,
1217                         };
1218
1219                         static const sd_json_dispatch_field dispatch_table[] = {
1220                                 { "Id",                    SD_JSON_VARIANT_STRING,        sd_json_dispatch_const_string, voffsetof(p, id),             SD_JSON_MANDATORY },
1221                                 { "RuntimePath",           SD_JSON_VARIANT_STRING,        json_dispatch_const_path,      voffsetof(p, runtime_path),   SD_JSON_MANDATORY },
1222                                 { "UID",                   _SD_JSON_VARIANT_TYPE_INVALID, sd_json_dispatch_uid_gid,      voffsetof(p, uid),            SD_JSON_MANDATORY },
1223                                 { "Seat",                  SD_JSON_VARIANT_STRING,        sd_json_dispatch_const_string, voffsetof(p, seat),           0                 },
1224                                 { "VTNr",                  _SD_JSON_VARIANT_TYPE_INVALID, sd_json_dispatch_uint,         voffsetof(p, vtnr),           0                 },
1225                                 {}
1226                         };
1227
1228                         r = sd_json_dispatch(vreply, dispatch_table, SD_JSON_ALLOW_EXTENSIONS, &p);
1229                         if (r < 0)
1230                                 return pam_syslog_errno(handle, LOG_ERR, r, "Failed to parse CreateSession() reply: %m");
1231
1232                         id = p.id;
1233                         runtime_path = p.runtime_path;
1234                         original_uid = p.uid;
1235                         real_seat = p.seat;
1236                         real_vtnr = p.vtnr;
1237                         existing = false; /* Even on D-Bus logind only returns false these days */
1238
1239                         done = true;
1240                 }
1241         }
1242
1243         if (!done) {
1244                 /* Let's release the D-Bus connection once we are done here, after all the session might live
1245                  * quite a long time, and we are not going to process the bus connection in that time, so
1246                  * let's better close before the daemon kicks us off because we are not processing
1247                  * anything. */
1248                 _cleanup_(pam_bus_data_disconnectp) PamBusData *d = NULL;
1249                 _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
1250
1251                 /* Talk to logind over the message bus */
1252                 r = pam_acquire_bus_connection(handle, "pam-systemd", debug, &bus, &d);
1253                 if (r != PAM_SUCCESS)
1254                         return r;
1255
1256                 _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
1257                 r = create_session_message(
1258                                 bus,
1259                                 handle,
1260                                 ur,
1261                                 c,
1262                                 /* avoid_pidfd = */ false,
1263                                 &m);
1264                 if (r < 0)
1265                         return pam_bus_log_create_error(handle, r);
1266
1267                 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
1268                 r = sd_bus_call(bus, m, LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC, &error, &reply);
1269                 if (r < 0 && sd_bus_error_has_name(&error, SD_BUS_ERROR_UNKNOWN_METHOD)) {
1270                         sd_bus_error_free(&error);
1271                         pam_debug_syslog(handle, debug,
1272                                          "CreateSessionWithPIDFD() API is not available, retrying with CreateSession().");
1273
1274                         m = sd_bus_message_unref(m);
1275                         r = create_session_message(bus,
1276                                                    handle,
1277                                                    ur,
1278                                                    c,
1279                                                    /* avoid_pidfd = */ true,
1280                                                    &m);
1281                         if (r < 0)
1282                                 return pam_bus_log_create_error(handle, r);
1283
1284                         r = sd_bus_call(bus, m, LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC, &error, &reply);
1285                 }
1286                 if (r < 0) {
1287                         if (sd_bus_error_has_name(&error, BUS_ERROR_SESSION_BUSY)) {
1288                                 /* We are already in a session, don't do anything */
1289                                 pam_debug_syslog(handle, debug,
1290                                                  "Not creating session: %s", bus_error_message(&error, r));
1291                                 *ret_seat = *ret_type = *ret_runtime_dir = NULL;
1292                                 return PAM_SUCCESS;
1293                         }
1294
1295                         pam_syslog(handle, LOG_ERR,
1296                                    "Failed to create session: %s", bus_error_message(&error, r));
1297                         return PAM_SESSION_ERR;
1298                 }
1299
1300                 r = sd_bus_message_read(
1301                                 reply,
1302                                 "soshusub",
1303                                 &id,
1304                                 &object_path,
1305                                 &runtime_path,
1306                                 /* session_fd = */ NULL,
1307                                 &original_uid,
1308                                 &real_seat,
1309                                 &real_vtnr,
1310                                 &existing);
1311                 if (r < 0)
1312                         return pam_bus_log_parse_error(handle, r);
1313         }
1314
1315         pam_debug_syslog(handle, debug,
1316                          "Reply from logind: "
1317                          "id=%s object_path=%s runtime_path=%s seat=%s vtnr=%u original_uid=%u",
1318                          id, strna(object_path), runtime_path, real_seat, real_vtnr, original_uid);
1319
1320         /* Please update manager_default_environment() in core/manager.c accordingly if more session envvars
1321          * shall be added. */
1322
1323         r = update_environment(handle, "XDG_SESSION_ID", id);
1324         if (r != PAM_SUCCESS)
1325                 return r;
1326
1327         /* Most likely we got the session/type/class from environment variables, but might have gotten the data
1328          * somewhere else (for example PAM module parameters). Let's now update the environment variables, so that this
1329          * data is inherited into the session processes, and programs can rely on them to be initialized. */
1330
1331         _cleanup_free_ char *real_type = strdup(c->type); /* make copy because this might point to env block, which we are going to update shortly */
1332         if (!real_type)
1333                 return pam_log_oom(handle);
1334
1335         r = update_environment(handle, "XDG_SESSION_TYPE", c->type);
1336         if (r != PAM_SUCCESS)
1337                 return r;
1338
1339         r = update_environment(handle, "XDG_SESSION_CLASS", c->class);
1340         if (r != PAM_SUCCESS)
1341                 return r;
1342
1343         r = update_environment(handle, "XDG_SESSION_DESKTOP", c->desktop);
1344         if (r != PAM_SUCCESS)
1345                 return r;
1346
1347         r = update_environment(handle, "XDG_SEAT", real_seat);
1348         if (r != PAM_SUCCESS)
1349                 return r;
1350
1351         if (real_vtnr > 0) {
1352                 char buf[DECIMAL_STR_MAX(real_vtnr)];
1353                 xsprintf(buf, "%u", real_vtnr);
1354
1355                 r = update_environment(handle, "XDG_VTNR", buf);
1356                 if (r != PAM_SUCCESS)
1357                         return r;
1358         }
1359
1360         r = pam_set_data(handle, "systemd.existing", INT_TO_PTR(!!existing), NULL);
1361         if (r != PAM_SUCCESS)
1362                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to install existing flag: @PAMERR@");
1363
1364         /* Don't set $XDG_RUNTIME_DIR if the user we now authenticated for does not match the
1365          * original user of the session. We do this in order not to result in privileged apps
1366          * clobbering the runtime directory unnecessarily. */
1367         _cleanup_free_ char *rt = NULL;
1368         if (original_uid == ur->uid && validate_runtime_directory(handle, runtime_path, ur->uid))
1369                 if (strdup_to(&rt, runtime_path) < 0)
1370                         return pam_log_oom(handle);
1371
1372         /* Everything worked, hence let's patch in the data we learned. Since 'real_set' points into the
1373          * D-Bus message, let's copy it and return it as a buffer */
1374         _cleanup_free_ char *rs = NULL;
1375         if (strdup_to(&rs, real_seat) < 0)
1376                 return pam_log_oom(handle);
1377
1378         c->vtnr = real_vtnr;
1379         c->seat = *ret_seat = TAKE_PTR(rs);
1380         c->type = *ret_type = TAKE_PTR(real_type);
1381         *ret_runtime_dir = TAKE_PTR(rt);
1382
1383         return PAM_SUCCESS;
1384 }
1385
1386 static int import_shell_credentials(pam_handle_t *handle) {
1387
1388         static const char *const propagate[] = {
1389                 "shell.prompt.prefix", "SHELL_PROMPT_PREFIX",
1390                 "shell.prompt.suffix", "SHELL_PROMPT_SUFFIX",
1391                 "shell.welcome",       "SHELL_WELCOME",
1392                 NULL
1393         };
1394         int r;
1395
1396         assert(handle);
1397
1398         STRV_FOREACH_PAIR(k, v, propagate) {
1399                 r = propagate_credential_to_environment(handle, *k, *v);
1400                 if (r != PAM_SUCCESS)
1401                         return r;
1402         }
1403
1404         return PAM_SUCCESS;
1405 }
1406
1407 static int mkdir_chown_open_directory(
1408                 int parent_fd,
1409                 const char *name,
1410                 uid_t uid,
1411                 gid_t gid,
1412                 mode_t mode) {
1413
1414         _cleanup_free_ char *t = NULL;
1415         int r;
1416
1417         assert(parent_fd >= 0);
1418         assert(name);
1419         assert(uid_is_valid(uid));
1420         assert(gid_is_valid(gid));
1421         assert(mode != MODE_INVALID);
1422
1423         for (unsigned attempt = 0;; attempt++) {
1424                 _cleanup_close_ int fd = openat(parent_fd, name, O_CLOEXEC|O_DIRECTORY|O_NOFOLLOW);
1425                 if (fd >= 0)
1426                         return TAKE_FD(fd);
1427                 if (errno != ENOENT)
1428                         return -errno;
1429
1430                 /* Let's create the directory under a temporary name first, since we want to make sure that
1431                  * once it appears under the right name it has the right ownership */
1432                 r = tempfn_random(name, /* extra= */ NULL, &t);
1433                 if (r < 0)
1434                         return r;
1435
1436                 fd = open_mkdir_at(parent_fd, t, O_CLOEXEC|O_EXCL, 0700); /* Use restrictive mode until ownership is in order */
1437                 if (fd < 0)
1438                         return fd;
1439
1440                 r = RET_NERRNO(fchown(fd, uid, gid));
1441                 if (r < 0)
1442                         goto fail;
1443
1444                 r = RET_NERRNO(fchmod(fd, mode));
1445                 if (r < 0)
1446                         goto fail;
1447
1448                 r = rename_noreplace(parent_fd, t, parent_fd, name);
1449                 if (r >= 0)
1450                         return TAKE_FD(fd);
1451                 if (r != -EEXIST || attempt >= 5)
1452                         goto fail;
1453
1454                 /* Maybe some other login attempt created the directory at the same time? Let's retry */
1455                 (void) unlinkat(parent_fd, t, AT_REMOVEDIR);
1456                 t = mfree(t);
1457         }
1458
1459 fail:
1460         (void) unlinkat(parent_fd, ASSERT_PTR(t), AT_REMOVEDIR);
1461         return r;
1462 }
1463
1464 static int make_area_runtime_directory(
1465                 pam_handle_t *handle,
1466                 UserRecord *ur,
1467                 const char *runtime_directory,
1468                 const char *area,
1469                 char **ret) {
1470
1471         assert(handle);
1472         assert(ur);
1473         assert(runtime_directory);
1474         assert(area);
1475         assert(ret);
1476
1477         /* Let's be careful with creating these directories, the runtime directory is owned by the user after all,
1478          * and they might play symlink games with us. */
1479
1480         _cleanup_close_ int fd = open(runtime_directory, O_CLOEXEC|O_PATH|O_DIRECTORY);
1481         if (fd < 0)
1482                 return pam_syslog_errno(handle, LOG_ERR, errno, "Unable to open runtime directory '%s': %m", runtime_directory);
1483
1484         _cleanup_close_ int fd_areas = mkdir_chown_open_directory(fd, "Areas", ur->uid, user_record_gid(ur), 0755);
1485         if (fd_areas < 0)
1486                 return pam_syslog_errno(handle, LOG_ERR, fd_areas, "Unable to create 'Areas' directory below '%s': %m", runtime_directory);
1487
1488         _cleanup_close_ int fd_area = mkdir_chown_open_directory(fd_areas, area, ur->uid, user_record_gid(ur), 0755);
1489         if (fd_area < 0)
1490                 return pam_syslog_errno(handle, LOG_ERR, fd_area, "Unable to create '%s' directory below '%s/Areas': %m", area, runtime_directory);
1491
1492         char *j = path_join(runtime_directory, "Areas", area);
1493         if (!j)
1494                 return pam_log_oom(handle);
1495
1496         *ret = j;
1497         return 0;
1498 }
1499
1500 static int setup_environment(
1501                 pam_handle_t *handle,
1502                 UserRecord *ur,
1503                 const char *runtime_directory,
1504                 const char *area,
1505                 bool debug) {
1506
1507         int r;
1508
1509         assert(handle);
1510         assert(ur);
1511
1512         const char *h = ASSERT_PTR(user_record_home_directory(ur));
1513
1514         /* If an empty area string is specified, this means an explicit: do not use the area logic, normalize this here */
1515         area = empty_to_null(area);
1516
1517         _cleanup_free_ char *ha = NULL, *area_copy = NULL;
1518         if (area) {
1519                 _cleanup_free_ char *j = path_join(h, "Areas", area);
1520                 if (!j)
1521                         return pam_log_oom(handle);
1522
1523                 _cleanup_close_ int fd = -EBADF;
1524                 r = chase(j, /* root= */ NULL, CHASE_MUST_BE_DIRECTORY, &ha, &fd);
1525                 if (r < 0) {
1526                         /* Log the precise error */
1527                         pam_syslog_errno(handle, LOG_WARNING, r, "Path '%s' of requested user area '%s' is not accessible, reverting to regular home directory: %m", j, area);
1528
1529                         /* Also tell the user directly at login, but a bit more vague */
1530                         pam_info(handle, "Path '%s' of requested user area '%s' is not accessible, reverting to regular home directory.", j, area);
1531                         area = NULL;
1532                 } else {
1533                         /* Validate that the target is definitely owned by user */
1534                         struct stat st;
1535                         if (fstat(fd, &st) < 0)
1536                                 return pam_syslog_errno(handle, LOG_ERR, errno, "Unable to fstat() target area directory '%s': %m", ha);
1537
1538                         if (st.st_uid != ur->uid) {
1539                                 pam_syslog(handle, LOG_ERR, "Path '%s' of requested user area '%s' is not owned by user, reverting to regular home directory.", ha, area);
1540
1541                                 /* Also tell the user directly at login. */
1542                                 pam_info(handle, "Path '%s' of requested user area '%s' is not owned by user, reverting to regular home directory.", ha, area);
1543                                 area = NULL;
1544                         } else {
1545                                 /* All good, now make a copy of the area string, since we quite likely are
1546                                  * going to invalidate it (if it points into the environment block), via the
1547                                  * update_environment() call below */
1548                                 area_copy = strdup(area);
1549                                 if (!area_copy)
1550                                         return pam_log_oom(handle);
1551
1552                                 pam_debug_syslog(handle, debug, "Area '%s' selected, setting $HOME to '%s'.", area, ha);
1553                                 h = ha;
1554                                 area = area_copy;
1555                         }
1556                 }
1557         }
1558
1559         r = update_environment(handle, "XDG_AREA", area);
1560         if (r != PAM_SUCCESS)
1561                 return r;
1562
1563         r = update_environment(handle, "HOME", h);
1564         if (r != PAM_SUCCESS)
1565                 return r;
1566
1567         _cleanup_free_ char *per_area_runtime_directory = NULL;
1568         if (runtime_directory && area) {
1569                 /* Also create a per-area subdirectory for $XDG_RUNTIME_DIR, so that each area has their own
1570                  * set of runtime services. We follow the same directory structure as for $HOME. Note that we
1571                  * do not define any form of automatic clean-up for the per-aera subdirs beyond the regular
1572                  * clean-up of the whole $XDG_RUNTIME_DIRECTORY hierarchy when the user finally logs out. */
1573
1574                 r = make_area_runtime_directory(handle, ur, runtime_directory, area, &per_area_runtime_directory);
1575                 if (r != PAM_SUCCESS)
1576                         return r;
1577
1578                 runtime_directory = per_area_runtime_directory;
1579         }
1580
1581         r = update_environment(handle, "XDG_RUNTIME_DIR", runtime_directory);
1582         if (r != PAM_SUCCESS)
1583                 return r;
1584
1585         return export_legacy_dbus_address(handle, runtime_directory);
1586 }
1587
1588 static int open_osc_context(pam_handle_t *handle, const char *session_type, UserRecord *ur) {
1589         int r;
1590
1591         assert(handle);
1592         assert(ur);
1593
1594         /* If this is a TTY session, then output the session start OSC sequence */
1595
1596         if (!streq_ptr(session_type, "tty"))
1597                 return PAM_SUCCESS;
1598
1599         const char *e = pam_getenv(handle, "TERM");
1600         if (!e)
1601                 e = getenv("TERM");
1602         if (streq_ptr(e, "dumb"))
1603                 return PAM_SUCCESS;
1604
1605         /* NB: we output directly to stdout, instead of going via pam_info() or so, because that's too
1606          * high-level for us, as it suffixes the output with a newline, expecting a full blown text message
1607          * as prompt string, not just an ANSI sequence. Note that PAM's conv_misc() actually goes to stdout
1608          * anyway, hence let's do so here too, but only after careful validation. */
1609         if (!isatty_safe(STDOUT_FILENO))
1610                 return PAM_SUCCESS;
1611
1612         /* Keep a reference to the TTY we are operating on, so that we can issue the OSC close sequence also
1613          * if the TTY is already closed. We use an O_PATH reference here, rather than a properly opened fd,
1614          * so that we don't delay tty hang-up. */
1615         _cleanup_close_ int tty_opath_fd = fd_reopen(STDOUT_FILENO, O_PATH|O_CLOEXEC);
1616         if (tty_opath_fd < 0)
1617                 pam_syslog_errno(handle, LOG_DEBUG, tty_opath_fd, "Failed to pin TTY, ignoring: %m");
1618         else
1619                 tty_opath_fd = fd_move_above_stdio(tty_opath_fd);
1620
1621         _cleanup_free_ char *osc = NULL;
1622         sd_id128_t osc_id;
1623         r = osc_context_open_session(
1624                         ur->user_name,
1625                         pam_getenv(handle, "XDG_SESSION_ID"),
1626                         &osc,
1627                         &osc_id);
1628         if (r < 0)
1629                 return pam_syslog_errno(handle, LOG_ERR, r, "Failed to prepare OSC sequence: %m");
1630
1631         r = loop_write(STDOUT_FILENO, osc, SIZE_MAX);
1632         if (r < 0)
1633                 return pam_syslog_errno(handle, LOG_ERR, r, "Failed to write OSC sequence to TTY: %m");
1634
1635         /* Remember the OSC context id, so that we can close it cleanly later */
1636         _cleanup_free_ sd_id128_t *osc_id_copy = newdup(sd_id128_t, &osc_id, 1);
1637         if (!osc_id_copy)
1638                 return pam_log_oom(handle);
1639
1640         r = pam_set_data(handle, "systemd.osc-context-id", osc_id_copy, pam_cleanup_free);
1641         if (r != PAM_SUCCESS)
1642                 return pam_syslog_pam_error(handle, LOG_ERR, r,
1643                                             "Failed to set PAM OSC sequence ID data: @PAMERR@");
1644
1645         TAKE_PTR(osc_id_copy);
1646
1647         if (tty_opath_fd >= 0) {
1648                 r = pam_set_data(handle, "systemd.osc-context-fd", FD_TO_PTR(tty_opath_fd), pam_cleanup_close);
1649                 if (r != PAM_SUCCESS)
1650                         return pam_syslog_pam_error(handle, LOG_ERR, r,
1651                                                     "Failed to set PAM OSC sequence fd data: @PAMERR@");
1652
1653                 TAKE_FD(tty_opath_fd);
1654         }
1655
1656         return PAM_SUCCESS;
1657 }
1658
1659 static int close_osc_context(pam_handle_t *handle) {
1660         int r;
1661
1662         assert(handle);
1663
1664         const void *p;
1665         int tty_opath_fd = -EBADF;
1666         r = pam_get_data(handle, "systemd.osc-context-fd", &p);
1667         if (r == PAM_SUCCESS)
1668                 tty_opath_fd = PTR_TO_FD(p);
1669         else if (r != PAM_NO_MODULE_DATA)
1670                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM OSC context fd: @PAMERR@");
1671         if (tty_opath_fd < 0)
1672                 return PAM_SUCCESS;
1673
1674         const sd_id128_t *osc_id = NULL;
1675         r = pam_get_data(handle, "systemd.osc-context-id", (const void**) &osc_id);
1676         if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA))
1677                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM OSC context id data: @PAMERR@");
1678         if (!osc_id)
1679                 return PAM_SUCCESS;
1680
1681         /* Now open the original TTY again, so that we can write on it */
1682         _cleanup_close_ int fd = fd_reopen(tty_opath_fd, O_WRONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
1683         if (fd < 0) {
1684                 pam_syslog_errno(handle, LOG_DEBUG, fd, "Failed to reopen TTY, ignoring: %m");
1685                 return PAM_SUCCESS;
1686         }
1687
1688         /* /bin/login calls us with fds 0, 1, 2 closed, which is just weird. Let's step outside of that
1689          * range, just in case pam_syslog() or so logs to stderr */
1690         fd = fd_move_above_stdio(fd);
1691
1692         /* Safety check, let's verify this is a valid TTY we just opened */
1693         if (!isatty_safe(fd))
1694                 return PAM_SUCCESS;
1695
1696         _cleanup_free_ char *osc = NULL;
1697         r = osc_context_close(*osc_id, &osc);
1698         if (r < 0)
1699                 return pam_syslog_errno(handle, LOG_ERR, r, "Failed to prepare OSC sequence: %m");
1700
1701         r = loop_write(fd, osc, SIZE_MAX);
1702         if (r < 0)
1703                 return pam_syslog_errno(handle, LOG_ERR, r, "Failed to write OSC sequence to TTY: %m");
1704
1705         return PAM_SUCCESS;
1706 }
1707
1708 _public_ PAM_EXTERN int pam_sm_open_session(
1709                 pam_handle_t *handle,
1710                 int flags,
1711                 int argc, const char **argv) {
1712
1713         int r;
1714
1715         assert(handle);
1716
1717         pam_log_setup();
1718
1719         uint64_t default_capability_bounding_set = UINT64_MAX, default_capability_ambient_set = UINT64_MAX;
1720         const char *class_pam = NULL, *type_pam = NULL, *desktop_pam = NULL, *area_pam = NULL;
1721         bool debug = false;
1722         if (parse_argv(handle,
1723                        argc, argv,
1724                        &class_pam,
1725                        &type_pam,
1726                        &desktop_pam,
1727                        &area_pam,
1728                        &debug,
1729                        &default_capability_bounding_set,
1730                        &default_capability_ambient_set) < 0)
1731                 return PAM_SESSION_ERR;
1732
1733         pam_debug_syslog(handle, debug, "pam-systemd initializing");
1734
1735         _cleanup_(user_record_unrefp) UserRecord *ur = NULL;
1736         r = acquire_user_record(handle, &ur);
1737         if (r != PAM_SUCCESS)
1738                 return r;
1739
1740         SessionContext c = {};
1741         r = pam_get_item_many(
1742                         handle,
1743                         PAM_SERVICE,  &c.service,
1744                         PAM_XDISPLAY, &c.display,
1745                         PAM_TTY,      &c.tty,
1746                         PAM_RUSER,    &c.remote_user,
1747                         PAM_RHOST,    &c.remote_host);
1748         if (r != PAM_SUCCESS)
1749                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM items: @PAMERR@");
1750
1751         c.seat = getenv_harder(handle, "XDG_SEAT", NULL);
1752         c.vtnr = getenv_harder_uint32(handle, "XDG_VTNR", 0);
1753         c.type = getenv_harder(handle, "XDG_SESSION_TYPE", type_pam);
1754         c.class = getenv_harder(handle, "XDG_SESSION_CLASS", class_pam);
1755         c.desktop = getenv_harder(handle, "XDG_SESSION_DESKTOP", desktop_pam);
1756         c.area = getenv_harder(handle, "XDG_AREA", area_pam);
1757         c.incomplete = getenv_harder_bool(handle, "XDG_SESSION_INCOMPLETE", false);
1758
1759         r = pam_get_data_many(
1760                         handle,
1761                         "systemd.memory_max",      &c.memory_max,
1762                         "systemd.tasks_max",       &c.tasks_max,
1763                         "systemd.cpu_weight",      &c.cpu_weight,
1764                         "systemd.io_weight",       &c.io_weight,
1765                         "systemd.runtime_max_sec", &c.runtime_max_sec);
1766         if (r != PAM_SUCCESS)
1767                 return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM data: @PAMERR@");
1768
1769         session_context_mangle(handle, &c, ur, debug);
1770
1771         _cleanup_free_ char *seat_buffer = NULL, *type_buffer = NULL, *runtime_dir = NULL;
1772         r = register_session(handle, &c, ur, debug, &seat_buffer, &type_buffer, &runtime_dir);
1773         if (r != PAM_SUCCESS)
1774                 return r;
1775
1776         r = import_shell_credentials(handle);
1777         if (r != PAM_SUCCESS)
1778                 return r;
1779
1780         r = setup_environment(handle, ur, runtime_dir, c.area, debug);
1781         if (r != PAM_SUCCESS)
1782                 return r;
1783
1784         if (default_capability_ambient_set == UINT64_MAX)
1785                 default_capability_ambient_set = pick_default_capability_ambient_set(ur, c.service, c.seat);
1786
1787         r = apply_user_record_settings(handle, ur, debug, default_capability_bounding_set, default_capability_ambient_set);
1788         if (r != PAM_SUCCESS)
1789                 return r;
1790
1791         return open_osc_context(handle, c.type, ur);
1792 }
1793
1794 _public_ PAM_EXTERN int pam_sm_close_session(
1795                 pam_handle_t *handle,
1796                 int flags,
1797                 int argc, const char **argv) {
1798
1799         const void *existing = NULL;
1800         bool debug = false;
1801         const char *id;
1802         int r;
1803
1804         assert(handle);
1805
1806         pam_log_setup();
1807
1808         if (parse_argv(handle,
1809                        argc, argv,
1810                        /* class= */ NULL,
1811                        /* type= */ NULL,
1812                        /* desktop= */ NULL,
1813                        /* area= */ NULL,
1814                        &debug,
1815                        /* default_capability_bounding_set */ NULL,
1816                        /* default_capability_ambient_set= */ NULL) < 0)
1817                 return PAM_SESSION_ERR;
1818
1819         pam_debug_syslog(handle, debug, "pam-systemd shutting down");
1820
1821         /* Only release session if it wasn't pre-existing when we
1822          * tried to create it */
1823         r = pam_get_data(handle, "systemd.existing", &existing);
1824         if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA))
1825                 return pam_syslog_pam_error(handle, LOG_ERR, r,
1826                                             "Failed to get PAM systemd.existing data: @PAMERR@");
1827
1828         (void) close_osc_context(handle);
1829
1830         id = pam_getenv(handle, "XDG_SESSION_ID");
1831         if (id && !existing) {
1832                 _cleanup_(sd_varlink_unrefp) sd_varlink *vl = NULL;
1833                 bool done = false;
1834
1835                 r = sd_varlink_connect_address(&vl, "/run/systemd/io.systemd.Login");
1836                 if (r < 0)
1837                         log_debug_errno(r, "Failed to connect to logind via Varlink, falling back to D-Bus: %m");
1838                 else {
1839                         _cleanup_(sd_json_variant_unrefp) sd_json_variant *vreply = NULL;
1840                         const char *error_id = NULL;
1841                         r = sd_varlink_callbo(
1842                                         vl,
1843                                         "io.systemd.Login.ReleaseSession",
1844                                         /* ret_reply= */ NULL,
1845                                         &error_id,
1846                                         SD_JSON_BUILD_PAIR_STRING("Id", id));
1847                         if (r < 0)
1848                                 return pam_syslog_errno(handle, LOG_ERR, r, "Failed to register session: %s", error_id);
1849                         if (error_id)
1850                                 return pam_syslog_errno(handle, LOG_ERR, sd_varlink_error_to_errno(error_id, vreply),
1851                                                         "Failed to issue ReleaseSession() varlink call: %s", error_id);
1852
1853                         done = true;
1854                 }
1855
1856                 if (!done) {
1857                         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
1858                         _cleanup_(pam_bus_data_disconnectp) PamBusData *d = NULL;
1859                         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
1860
1861                         /* Before we go and close the FIFO we need to tell logind that this is a clean session
1862                          * shutdown, so that it doesn't just go and slaughter us immediately after closing the fd */
1863
1864                         r = pam_acquire_bus_connection(handle, "pam-systemd", debug, &bus, &d);
1865                         if (r != PAM_SUCCESS)
1866                                 return r;
1867
1868                         r = bus_call_method(bus, bus_login_mgr, "ReleaseSession", &error, NULL, "s", id);
1869                         if (r < 0)
1870                                 return pam_syslog_pam_error(handle, LOG_ERR, PAM_SESSION_ERR,
1871                                                             "Failed to release session: %s", bus_error_message(&error, r));
1872                 }
1873         }
1874
1875         return PAM_SUCCESS;
1876 }