src/login/pam_systemd.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   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-util.h"
  24 #include "cgroup-setup.h"
  25 #include "errno-util.h"
  26 #include "fd-util.h"
  27 #include "fileio.h"
  28 #include "format-util.h"
  29 #include "fs-util.h"
  30 #include "hostname-util.h"
  31 #include "locale-util.h"
  32 #include "login-util.h"
  33 #include "macro.h"
  34 #include "pam-util.h"
  35 #include "parse-util.h"
  36 #include "path-util.h"
  37 #include "process-util.h"
  38 #include "rlimit-util.h"
  39 #include "socket-util.h"
  40 #include "stdio-util.h"
  41 #include "strv.h"
  42 #include "terminal-util.h"
  43 #include "user-util.h"
  44 #include "userdb.h"
  45
  46 #define LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC (2*USEC_PER_MINUTE)
  47
  48 static int parse_argv(
  49                 pam_handle_t *handle,
  50                 int argc, const char **argv,
  51                 const char **class,
  52                 const char **type,
  53                 const char **desktop,
  54                 bool *debug) {
  55
  56         unsigned i;
  57
  58         assert(argc >= 0);
  59         assert(argc == 0 || argv);
  60
  61         for (i = 0; i < (unsigned) argc; i++) {
  62                 const char *p;
  63
  64                 if ((p = startswith(argv[i], "class="))) {
  65                         if (class)
  66                                 *class = p;
  67
  68                 } else if ((p = startswith(argv[i], "type="))) {
  69                         if (type)
  70                                 *type = p;
  71
  72                 } else if ((p = startswith(argv[i], "desktop="))) {
  73                         if (desktop)
  74                                 *desktop = p;
  75
  76                 } else if (streq(argv[i], "debug")) {
  77                         if (debug)
  78                                 *debug = true;
  79
  80                 } else if ((p = startswith(argv[i], "debug="))) {
  81                         int k;
  82
  83                         k = parse_boolean(p);
  84                         if (k < 0)
  85                                 pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring: %s", p);
  86                         else if (debug)
  87                                 *debug = k;
  88
  89                 } else
  90                         pam_syslog(handle, LOG_WARNING, "Unknown parameter '%s', ignoring", argv[i]);
  91         }
  92
  93         return 0;
  94 }
  95
  96 static int acquire_user_record(
  97                 pam_handle_t *handle,
  98                 UserRecord **ret_record) {
  99
 100         _cleanup_(user_record_unrefp) UserRecord *ur = NULL;
 101         const char *username = NULL, *json = NULL;
 102         int r;
 103
 104         assert(handle);
 105
 106         r = pam_get_user(handle, &username, NULL);
 107         if (r != PAM_SUCCESS) {
 108                 pam_syslog(handle, LOG_ERR, "Failed to get user name: %s", pam_strerror(handle, r));
 109                 return r;
 110         }
 111
 112         if (isempty(username)) {
 113                 pam_syslog(handle, LOG_ERR, "User name not valid.");
 114                 return PAM_SERVICE_ERR;
 115         }
 116
 117         /* If pam_systemd_homed (or some other module) already acqired the user record we can reuse it
 118          * here. */
 119         r = pam_get_data(handle, "systemd-user-record", (const void**) &json);
 120         if (r != PAM_SUCCESS || !json) {
 121                 _cleanup_free_ char *formatted = NULL;
 122
 123                 if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) {
 124                         pam_syslog(handle, LOG_ERR, "Failed to get PAM user record data: %s", pam_strerror(handle, r));
 125                         return r;
 126                 }
 127
 128                 /* Request the record ourselves */
 129                 r = userdb_by_name(username, 0, &ur);
 130                 if (r < 0) {
 131                         pam_syslog(handle, LOG_ERR, "Failed to get user record: %s", strerror_safe(r));
 132                         return PAM_USER_UNKNOWN;
 133                 }
 134
 135                 r = json_variant_format(ur->json, 0, &formatted);
 136                 if (r < 0) {
 137                         pam_syslog(handle, LOG_ERR, "Failed to format user JSON: %s", strerror_safe(r));
 138                         return PAM_SERVICE_ERR;
 139                 }
 140
 141                 /* And cache it for everyone else */
 142                 r = pam_set_data(handle, "systemd-user-record", formatted, pam_cleanup_free);
 143                 if (r < 0) {
 144                         pam_syslog(handle, LOG_ERR, "Failed to set PAM user record data: %s", pam_strerror(handle, r));
 145                         return r;
 146                 }
 147
 148                 TAKE_PTR(formatted);
 149         } else {
 150                 _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
 151
 152                 /* Parse cached record */
 153                 r = json_parse(json, JSON_PARSE_SENSITIVE, &v, NULL, NULL);
 154                 if (r < 0) {
 155                         pam_syslog(handle, LOG_ERR, "Failed to parse JSON user record: %s", strerror_safe(r));
 156                         return PAM_SERVICE_ERR;
 157                 }
 158
 159                 ur = user_record_new();
 160                 if (!ur)
 161                         return pam_log_oom(handle);
 162
 163                 r = user_record_load(ur, v, USER_RECORD_LOAD_REFUSE_SECRET);
 164                 if (r < 0) {
 165                         pam_syslog(handle, LOG_ERR, "Failed to load user record: %s", strerror_safe(r));
 166                         return PAM_SERVICE_ERR;
 167                 }
 168
 169                 /* Safety check if cached record actually matches what we are looking for */
 170                 if (!streq_ptr(username, ur->user_name)) {
 171                         pam_syslog(handle, LOG_ERR, "Acquired user record does not match user name.");
 172                         return PAM_SERVICE_ERR;
 173                 }
 174         }
 175
 176         if (!uid_is_valid(ur->uid)) {
 177                 pam_syslog(handle, LOG_ERR, "Acquired user record does not have a UID.");
 178                 return PAM_SERVICE_ERR;
 179         }
 180
 181         if (ret_record)
 182                 *ret_record = TAKE_PTR(ur);
 183
 184         return PAM_SUCCESS;
 185 }
 186
 187 static bool display_is_local(const char *display) {
 188         assert(display);
 189
 190         return
 191                 display[0] == ':' &&
 192                 display[1] >= '0' &&
 193                 display[1] <= '9';
 194 }
 195
 196 static int socket_from_display(const char *display, char **path) {
 197         size_t k;
 198         char *f, *c;
 199
 200         assert(display);
 201         assert(path);
 202
 203         if (!display_is_local(display))
 204                 return -EINVAL;
 205
 206         k = strspn(display+1, "0123456789");
 207
 208         f = new(char, STRLEN("/tmp/.X11-unix/X") + k + 1);
 209         if (!f)
 210                 return -ENOMEM;
 211
 212         c = stpcpy(f, "/tmp/.X11-unix/X");
 213         memcpy(c, display+1, k);
 214         c[k] = 0;
 215
 216         *path = f;
 217
 218         return 0;
 219 }
 220
 221 static int get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) {
 222         union sockaddr_union sa;
 223         socklen_t sa_len;
 224         _cleanup_free_ char *p = NULL, *sys_path = NULL, *tty = NULL;
 225         _cleanup_close_ int fd = -1;
 226         struct ucred ucred;
 227         int v, r;
 228         dev_t display_ctty;
 229
 230         assert(display);
 231         assert(vtnr);
 232
 233         /* We deduce the X11 socket from the display name, then use
 234          * SO_PEERCRED to determine the X11 server process, ask for
 235          * the controlling tty of that and if it's a VC then we know
 236          * the seat and the virtual terminal. Sounds ugly, is only
 237          * semi-ugly. */
 238
 239         r = socket_from_display(display, &p);
 240         if (r < 0)
 241                 return r;
 242         r = sockaddr_un_set_path(&sa.un, p);
 243         if (r < 0)
 244                 return r;
 245         sa_len = r;
 246
 247         fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
 248         if (fd < 0)
 249                 return -errno;
 250
 251         if (connect(fd, &sa.sa, sa_len) < 0)
 252                 return -errno;
 253
 254         r = getpeercred(fd, &ucred);
 255         if (r < 0)
 256                 return r;
 257
 258         r = get_ctty_devnr(ucred.pid, &display_ctty);
 259         if (r < 0)
 260                 return r;
 261
 262         if (asprintf(&sys_path, "/sys/dev/char/%d:%d", major(display_ctty), minor(display_ctty)) < 0)
 263                 return -ENOMEM;
 264         r = readlink_value(sys_path, &tty);
 265         if (r < 0)
 266                 return r;
 267
 268         v = vtnr_from_tty(tty);
 269         if (v < 0)
 270                 return v;
 271         else if (v == 0)
 272                 return -ENOENT;
 273
 274         if (seat)
 275                 *seat = "seat0";
 276         *vtnr = (uint32_t) v;
 277
 278         return 0;
 279 }
 280
 281 static int export_legacy_dbus_address(
 282                 pam_handle_t *handle,
 283                 uid_t uid,
 284                 const char *runtime) {
 285
 286         const char *s;
 287         _cleanup_free_ char *t = NULL;
 288         int r = PAM_BUF_ERR;
 289
 290         /* We need to export $DBUS_SESSION_BUS_ADDRESS because various applications will not connect
 291          * correctly to the bus without it. This setting matches what dbus.socket does for the user
 292          * session using 'systemctl --user set-environment'. We want to have the same configuration
 293          * in processes started from the PAM session.
 294          *
 295          * The setting of the address is guarded by the access() check because it is also possible to compile
 296          * dbus without --enable-user-session, in which case this socket is not used, and
 297          * $DBUS_SESSION_BUS_ADDRESS should not be set. An alternative approach would to not do the access()
 298          * check here, and let applications try on their own, by using "unix:path=%s/bus;autolaunch:". But we
 299          * expect the socket to be present by the time we do this check, so we can just as well check once
 300          * here. */
 301
 302         s = strjoina(runtime, "/bus");
 303         if (access(s, F_OK) < 0)
 304                 return PAM_SUCCESS;
 305
 306         if (asprintf(&t, DEFAULT_USER_BUS_ADDRESS_FMT, runtime) < 0)
 307                 return pam_log_oom(handle);
 308
 309         r = pam_misc_setenv(handle, "DBUS_SESSION_BUS_ADDRESS", t, 0);
 310         if (r != PAM_SUCCESS) {
 311                 pam_syslog(handle, LOG_ERR, "Failed to set bus variable: %s", pam_strerror(handle, r));
 312                 return r;
 313         }
 314
 315         return PAM_SUCCESS;
 316 }
 317
 318 static int append_session_memory_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 319         uint64_t val;
 320         int r;
 321
 322         if (isempty(limit))
 323                 return PAM_SUCCESS;
 324
 325         if (streq(limit, "infinity")) {
 326                 r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", (uint64_t)-1);
 327                 if (r < 0)
 328                         return pam_bus_log_create_error(handle, r);
 329
 330                 return PAM_SUCCESS;
 331         }
 332
 333         r = parse_permille(limit);
 334         if (r >= 0) {
 335                 r = sd_bus_message_append(m, "(sv)", "MemoryMaxScale", "u", (uint32_t) (((uint64_t) r * UINT32_MAX) / 1000U));
 336                 if (r < 0)
 337                         return pam_bus_log_create_error(handle, r);
 338
 339                 return PAM_SUCCESS;
 340         }
 341
 342         r = parse_size(limit, 1024, &val);
 343         if (r >= 0) {
 344                 r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", val);
 345                 if (r < 0)
 346                         return pam_bus_log_create_error(handle, r);
 347
 348                 return PAM_SUCCESS;
 349         }
 350
 351         pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.memory_max, ignoring: %s", limit);
 352         return PAM_SUCCESS;
 353 }
 354
 355 static int append_session_runtime_max_sec(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 356         usec_t val;
 357         int r;
 358
 359         /* No need to parse "infinity" here, it will be set by default later in scope_init() */
 360         if (isempty(limit) || streq(limit, "infinity"))
 361                 return PAM_SUCCESS;
 362
 363         r = parse_sec(limit, &val);
 364         if (r >= 0) {
 365                 r = sd_bus_message_append(m, "(sv)", "RuntimeMaxUSec", "t", (uint64_t) val);
 366                 if (r < 0)
 367                         return pam_bus_log_create_error(handle, r);
 368         } else
 369                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.runtime_max_sec: %s, ignoring.", limit);
 370
 371         return PAM_SUCCESS;
 372 }
 373
 374 static int append_session_tasks_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 375         uint64_t val;
 376         int r;
 377
 378         /* No need to parse "infinity" here, it will be set unconditionally later in manager_start_scope() */
 379         if (isempty(limit) || streq(limit, "infinity"))
 380                 return PAM_SUCCESS;
 381
 382         r = safe_atou64(limit, &val);
 383         if (r >= 0) {
 384                 r = sd_bus_message_append(m, "(sv)", "TasksMax", "t", val);
 385                 if (r < 0)
 386                         return pam_bus_log_create_error(handle, r);
 387         } else
 388                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.tasks_max, ignoring: %s", limit);
 389
 390         return PAM_SUCCESS;
 391 }
 392
 393 static int append_session_cg_weight(pam_handle_t *handle, sd_bus_message *m, const char *limit, const char *field) {
 394         uint64_t val;
 395         int r;
 396
 397         if (isempty(limit))
 398                 return PAM_SUCCESS;
 399
 400         r = cg_weight_parse(limit, &val);
 401         if (r >= 0) {
 402                 r = sd_bus_message_append(m, "(sv)", field, "t", val);
 403                 if (r < 0)
 404                         return pam_bus_log_create_error(handle, r);
 405         } else if (streq(field, "CPUWeight"))
 406                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.cpu_weight, ignoring: %s", limit);
 407         else
 408                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.io_weight, ignoring: %s", limit);
 409
 410         return PAM_SUCCESS;
 411 }
 412
 413 static const char* getenv_harder(pam_handle_t *handle, const char *key, const char *fallback) {
 414         const char *v;
 415
 416         assert(handle);
 417         assert(key);
 418
 419         /* Looks for an environment variable, preferably in the environment block associated with the
 420          * specified PAM handle, falling back to the process' block instead. Why check both? Because we want
 421          * to permit configuration of session properties from unit files that invoke PAM services, so that
 422          * PAM services don't have to be reworked to set systemd-specific properties, but these properties
 423          * can still be set from the unit file Environment= block. */
 424
 425         v = pam_getenv(handle, key);
 426         if (!isempty(v))
 427                 return v;
 428
 429         /* We use secure_getenv() here, since we might get loaded into su/sudo, which are SUID. Ideally
 430          * they'd clean up the environment before invoking foreign code (such as PAM modules), but alas they
 431          * currently don't (to be precise, they clean up the environment they pass to their children, but
 432          * not their own environ[]). */
 433         v = secure_getenv(key);
 434         if (!isempty(v))
 435                 return v;
 436
 437         return fallback;
 438 }
 439
 440 static int update_environment(pam_handle_t *handle, const char *key, const char *value) {
 441         int r;
 442
 443         assert(handle);
 444         assert(key);
 445
 446         /* Updates the environment, but only if there's actually a value set. Also, log about errors */
 447
 448         if (isempty(value))
 449                 return PAM_SUCCESS;
 450
 451         r = pam_misc_setenv(handle, key, value, 0);
 452         if (r != PAM_SUCCESS)
 453                 pam_syslog(handle, LOG_ERR, "Failed to set environment variable %s: %s", key, pam_strerror(handle, r));
 454
 455         return r;
 456 }
 457
 458 static bool validate_runtime_directory(pam_handle_t *handle, const char *path, uid_t uid) {
 459         struct stat st;
 460
 461         assert(handle);
 462         assert(path);
 463
 464         /* Just some extra paranoia: let's not set $XDG_RUNTIME_DIR if the directory we'd set it to isn't actually set
 465          * up properly for us. */
 466
 467         if (lstat(path, &st) < 0) {
 468                 pam_syslog(handle, LOG_ERR, "Failed to stat() runtime directory '%s': %s", path, strerror_safe(errno));
 469                 goto fail;
 470         }
 471
 472         if (!S_ISDIR(st.st_mode)) {
 473                 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not actually a directory.", path);
 474                 goto fail;
 475         }
 476
 477         if (st.st_uid != uid) {
 478                 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not owned by UID " UID_FMT ", as it should.", path, uid);
 479                 goto fail;
 480         }
 481
 482         return true;
 483
 484 fail:
 485         pam_syslog(handle, LOG_WARNING, "Not setting $XDG_RUNTIME_DIR, as the directory is not in order.");
 486         return false;
 487 }
 488
 489 static int pam_putenv_and_log(pam_handle_t *handle, const char *e, bool debug) {
 490         int r;
 491
 492         assert(handle);
 493         assert(e);
 494
 495         r = pam_putenv(handle, e);
 496         if (r != PAM_SUCCESS) {
 497                 pam_syslog(handle, LOG_ERR, "Failed to set PAM environment variable %s: %s", e, pam_strerror(handle, r));
 498                 return r;
 499         }
 500
 501         if (debug)
 502                 pam_syslog(handle, LOG_DEBUG, "PAM environment variable %s set based on user record.", e);
 503
 504         return PAM_SUCCESS;
 505 }
 506
 507 static int apply_user_record_settings(pam_handle_t *handle, UserRecord *ur, bool debug) {
 508         char **i;
 509         int r;
 510
 511         assert(handle);
 512         assert(ur);
 513
 514         if (ur->umask != MODE_INVALID) {
 515                 umask(ur->umask);
 516
 517                 if (debug)
 518                         pam_syslog(handle, LOG_DEBUG, "Set user umask to %04o based on user record.", ur->umask);
 519         }
 520
 521         STRV_FOREACH(i, ur->environment) {
 522                 _cleanup_free_ char *n = NULL;
 523                 const char *e;
 524
 525                 assert_se(e = strchr(*i, '=')); /* environment was already validated while parsing JSON record, this thus must hold */
 526
 527                 n = strndup(*i, e - *i);
 528                 if (!n)
 529                         return pam_log_oom(handle);
 530
 531                 if (pam_getenv(handle, n)) {
 532                         if (debug)
 533                                 pam_syslog(handle, LOG_DEBUG, "PAM environment variable $%s already set, not changing based on record.", *i);
 534                         continue;
 535                 }
 536
 537                 r = pam_putenv_and_log(handle, *i, debug);
 538                 if (r != PAM_SUCCESS)
 539                         return r;
 540         }
 541
 542         if (ur->email_address) {
 543                 if (pam_getenv(handle, "EMAIL")) {
 544                         if (debug)
 545                                 pam_syslog(handle, LOG_DEBUG, "PAM environment variable $EMAIL already set, not changing based on user record.");
 546                 } else {
 547                         _cleanup_free_ char *joined = NULL;
 548
 549                         joined = strjoin("EMAIL=", ur->email_address);
 550                         if (!joined)
 551                                 return pam_log_oom(handle);
 552
 553                         r = pam_putenv_and_log(handle, joined, debug);
 554                         if (r != PAM_SUCCESS)
 555                                 return r;
 556                 }
 557         }
 558
 559         if (ur->time_zone) {
 560                 if (pam_getenv(handle, "TZ")) {
 561                         if (debug)
 562                                 pam_syslog(handle, LOG_DEBUG, "PAM environment variable $TZ already set, not changing based on user record.");
 563                 } else if (!timezone_is_valid(ur->time_zone, LOG_DEBUG)) {
 564                         if (debug)
 565                                 pam_syslog(handle, LOG_DEBUG, "Time zone specified in user record is not valid locally, not setting $TZ.");
 566                 } else {
 567                         _cleanup_free_ char *joined = NULL;
 568
 569                         joined = strjoin("TZ=:", ur->time_zone);
 570                         if (!joined)
 571                                 return pam_log_oom(handle);
 572
 573                         r = pam_putenv_and_log(handle, joined, debug);
 574                         if (r != PAM_SUCCESS)
 575                                 return r;
 576                 }
 577         }
 578
 579         if (ur->preferred_language) {
 580                 if (pam_getenv(handle, "LANG")) {
 581                         if (debug)
 582                                 pam_syslog(handle, LOG_DEBUG, "PAM environment variable $LANG already set, not changing based on user record.");
 583                 } else if (!locale_is_valid(ur->preferred_language)) {
 584                         if (debug)
 585                                 pam_syslog(handle, LOG_DEBUG, "Preferred language specified in user record is not valid locally, not setting $LANG.");
 586                 } else {
 587                         _cleanup_free_ char *joined = NULL;
 588
 589                         joined = strjoin("LANG=", ur->preferred_language);
 590                         if (!joined)
 591                                 return pam_log_oom(handle);
 592
 593                         r = pam_putenv_and_log(handle, joined, debug);
 594                         if (r != PAM_SUCCESS)
 595                                 return r;
 596                 }
 597         }
 598
 599         if (nice_is_valid(ur->nice_level)) {
 600                 if (nice(ur->nice_level) < 0)
 601                         pam_syslog(handle, LOG_ERR, "Failed to set nice level to %i, ignoring: %s", ur->nice_level, strerror_safe(errno));
 602                 else if (debug)
 603                         pam_syslog(handle, LOG_DEBUG, "Nice level set, based on user record.");
 604         }
 605
 606         for (int rl = 0; rl < _RLIMIT_MAX; rl++) {
 607
 608                 if (!ur->rlimits[rl])
 609                         continue;
 610
 611                 r = setrlimit_closest(rl, ur->rlimits[rl]);
 612                 if (r < 0)
 613                         pam_syslog(handle, LOG_ERR, "Failed to set resource limit %s, ignoring: %s", rlimit_to_string(rl), strerror_safe(r));
 614                 else if (debug)
 615                         pam_syslog(handle, LOG_DEBUG, "Resource limit %s set, based on user record.", rlimit_to_string(rl));
 616         }
 617
 618         return PAM_SUCCESS;
 619 }
 620
 621 _public_ PAM_EXTERN int pam_sm_open_session(
 622                 pam_handle_t *handle,
 623                 int flags,
 624                 int argc, const char **argv) {
 625
 626         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 627         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
 628         const char
 629                 *id, *object_path, *runtime_path,
 630                 *service = NULL,
 631                 *tty = NULL, *display = NULL,
 632                 *remote_user = NULL, *remote_host = NULL,
 633                 *seat = NULL,
 634                 *type = NULL, *class = NULL,
 635                 *class_pam = NULL, *type_pam = NULL, *cvtnr = NULL, *desktop = NULL, *desktop_pam = NULL,
 636                 *memory_max = NULL, *tasks_max = NULL, *cpu_weight = NULL, *io_weight = NULL, *runtime_max_sec = NULL;
 637         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
 638         _cleanup_(user_record_unrefp) UserRecord *ur = NULL;
 639         int session_fd = -1, existing, r;
 640         bool debug = false, remote;
 641         uint32_t vtnr = 0;
 642         uid_t original_uid;
 643
 644         assert(handle);
 645
 646         /* Make this a NOP on non-logind systems */
 647         if (!logind_running())
 648                 return PAM_SUCCESS;
 649
 650         if (parse_argv(handle,
 651                        argc, argv,
 652                        &class_pam,
 653                        &type_pam,
 654                        &desktop_pam,
 655                        &debug) < 0)
 656                 return PAM_SESSION_ERR;
 657
 658         if (debug)
 659                 pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing");
 660
 661         r = acquire_user_record(handle, &ur);
 662         if (r != PAM_SUCCESS)
 663                 return r;
 664
 665         /* Make sure we don't enter a loop by talking to
 666          * systemd-logind when it is actually waiting for the
 667          * background to finish start-up. If the service is
 668          * "systemd-user" we simply set XDG_RUNTIME_DIR and
 669          * leave. */
 670
 671         (void) pam_get_item(handle, PAM_SERVICE, (const void**) &service);
 672         if (streq_ptr(service, "systemd-user")) {
 673                 char rt[STRLEN("/run/user/") + DECIMAL_STR_MAX(uid_t)];
 674
 675                 xsprintf(rt, "/run/user/"UID_FMT, ur->uid);
 676                 if (validate_runtime_directory(handle, rt, ur->uid)) {
 677                         r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
 678                         if (r != PAM_SUCCESS) {
 679                                 pam_syslog(handle, LOG_ERR, "Failed to set runtime dir: %s", pam_strerror(handle, r));
 680                                 return r;
 681                         }
 682                 }
 683
 684                 r = export_legacy_dbus_address(handle, ur->uid, rt);
 685                 if (r != PAM_SUCCESS)
 686                         return r;
 687
 688                 r = apply_user_record_settings(handle, ur, debug);
 689                 if (r != PAM_SUCCESS)
 690                         return r;
 691
 692                 return PAM_SUCCESS;
 693         }
 694
 695         /* Otherwise, we ask logind to create a session for us */
 696
 697         (void) pam_get_item(handle, PAM_XDISPLAY, (const void**) &display);
 698         (void) pam_get_item(handle, PAM_TTY, (const void**) &tty);
 699         (void) pam_get_item(handle, PAM_RUSER, (const void**) &remote_user);
 700         (void) pam_get_item(handle, PAM_RHOST, (const void**) &remote_host);
 701
 702         seat = getenv_harder(handle, "XDG_SEAT", NULL);
 703         cvtnr = getenv_harder(handle, "XDG_VTNR", NULL);
 704         type = getenv_harder(handle, "XDG_SESSION_TYPE", type_pam);
 705         class = getenv_harder(handle, "XDG_SESSION_CLASS", class_pam);
 706         desktop = getenv_harder(handle, "XDG_SESSION_DESKTOP", desktop_pam);
 707
 708         tty = strempty(tty);
 709
 710         if (strchr(tty, ':')) {
 711                 /* A tty with a colon is usually an X11 display, placed there to show up in utmp. We rearrange things
 712                  * and don't pretend that an X display was a tty. */
 713                 if (isempty(display))
 714                         display = tty;
 715                 tty = NULL;
 716
 717         } else if (streq(tty, "cron")) {
 718                 /* cron is setting PAM_TTY to "cron" for some reason (the commit carries no information why, but
 719                  * probably because it wants to set it to something as pam_time/pam_access/… require PAM_TTY to be set
 720                  * (as they otherwise even try to update it!) — but cron doesn't actually allocate a TTY for its forked
 721                  * off processes.) */
 722                 type = "unspecified";
 723                 class = "background";
 724                 tty = NULL;
 725
 726         } else if (streq(tty, "ssh")) {
 727                 /* ssh has been setting PAM_TTY to "ssh" (for the same reason as cron does this, see above. For further
 728                  * details look for "PAM_TTY_KLUDGE" in the openssh sources). */
 729                 type ="tty";
 730                 class = "user";
 731                 tty = NULL; /* This one is particularly sad, as this means that ssh sessions — even though usually
 732                              * associated with a pty — won't be tracked by their tty in logind. This is because ssh
 733                              * does the PAM session registration early for new connections, and registers a pty only
 734                              * much later (this is because it doesn't know yet if it needs one at all, as whether to
 735                              * register a pty or not is negotiated much later in the protocol). */
 736
 737         } else
 738                 /* Chop off leading /dev prefix that some clients specify, but others do not. */
 739                 tty = skip_dev_prefix(tty);
 740
 741         /* If this fails vtnr will be 0, that's intended */
 742         if (!isempty(cvtnr))
 743                 (void) safe_atou32(cvtnr, &vtnr);
 744
 745         if (!isempty(display) && !vtnr) {
 746                 if (isempty(seat))
 747                         (void) get_seat_from_display(display, &seat, &vtnr);
 748                 else if (streq(seat, "seat0"))
 749                         (void) get_seat_from_display(display, NULL, &vtnr);
 750         }
 751
 752         if (seat && !streq(seat, "seat0") && vtnr != 0) {
 753                 if (debug)
 754                         pam_syslog(handle, LOG_DEBUG, "Ignoring vtnr %"PRIu32" for %s which is not seat0", vtnr, seat);
 755                 vtnr = 0;
 756         }
 757
 758         if (isempty(type))
 759                 type = !isempty(display) ? "x11" :
 760                            !isempty(tty) ? "tty" : "unspecified";
 761
 762         if (isempty(class))
 763                 class = streq(type, "unspecified") ? "background" : "user";
 764
 765         remote = !isempty(remote_host) && !is_localhost(remote_host);
 766
 767         (void) pam_get_data(handle, "systemd.memory_max", (const void **)&memory_max);
 768         (void) pam_get_data(handle, "systemd.tasks_max",  (const void **)&tasks_max);
 769         (void) pam_get_data(handle, "systemd.cpu_weight", (const void **)&cpu_weight);
 770         (void) pam_get_data(handle, "systemd.io_weight",  (const void **)&io_weight);
 771         (void) pam_get_data(handle, "systemd.runtime_max_sec", (const void **)&runtime_max_sec);
 772
 773         /* Talk to logind over the message bus */
 774
 775         r = pam_acquire_bus_connection(handle, &bus);
 776         if (r != PAM_SUCCESS)
 777                 return r;
 778
 779         if (debug) {
 780                 pam_syslog(handle, LOG_DEBUG, "Asking logind to create session: "
 781                            "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",
 782                            ur->uid, getpid_cached(),
 783                            strempty(service),
 784                            type, class, strempty(desktop),
 785                            strempty(seat), vtnr, strempty(tty), strempty(display),
 786                            yes_no(remote), strempty(remote_user), strempty(remote_host));
 787                 pam_syslog(handle, LOG_DEBUG, "Session limits: "
 788                            "memory_max=%s tasks_max=%s cpu_weight=%s io_weight=%s runtime_max_sec=%s",
 789                            strna(memory_max), strna(tasks_max), strna(cpu_weight), strna(io_weight), strna(runtime_max_sec));
 790         }
 791
 792         r = sd_bus_message_new_method_call(
 793                         bus,
 794                         &m,
 795                         "org.freedesktop.login1",
 796                         "/org/freedesktop/login1",
 797                         "org.freedesktop.login1.Manager",
 798                         "CreateSession");
 799         if (r < 0)
 800                 return pam_bus_log_create_error(handle, r);
 801
 802         r = sd_bus_message_append(m, "uusssssussbss",
 803                         (uint32_t) ur->uid,
 804                         0,
 805                         service,
 806                         type,
 807                         class,
 808                         desktop,
 809                         seat,
 810                         vtnr,
 811                         tty,
 812                         display,
 813                         remote,
 814                         remote_user,
 815                         remote_host);
 816         if (r < 0)
 817                 return pam_bus_log_create_error(handle, r);
 818
 819         r = sd_bus_message_open_container(m, 'a', "(sv)");
 820         if (r < 0)
 821                 return pam_bus_log_create_error(handle, r);
 822
 823         r = append_session_memory_max(handle, m, memory_max);
 824         if (r != PAM_SUCCESS)
 825                 return r;
 826
 827         r = append_session_runtime_max_sec(handle, m, runtime_max_sec);
 828         if (r != PAM_SUCCESS)
 829                 return r;
 830
 831         r = append_session_tasks_max(handle, m, tasks_max);
 832         if (r != PAM_SUCCESS)
 833                 return r;
 834
 835         r = append_session_cg_weight(handle, m, cpu_weight, "CPUWeight");
 836         if (r != PAM_SUCCESS)
 837                 return r;
 838
 839         r = append_session_cg_weight(handle, m, io_weight, "IOWeight");
 840         if (r != PAM_SUCCESS)
 841                 return r;
 842
 843         r = sd_bus_message_close_container(m);
 844         if (r < 0)
 845                 return pam_bus_log_create_error(handle, r);
 846
 847         r = sd_bus_call(bus, m, LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC, &error, &reply);
 848         if (r < 0) {
 849                 if (sd_bus_error_has_name(&error, BUS_ERROR_SESSION_BUSY)) {
 850                         if (debug)
 851                                 pam_syslog(handle, LOG_DEBUG, "Not creating session: %s", bus_error_message(&error, r));
 852                         return PAM_SUCCESS;
 853                 } else {
 854                         pam_syslog(handle, LOG_ERR, "Failed to create session: %s", bus_error_message(&error, r));
 855                         return PAM_SESSION_ERR;
 856                 }
 857         }
 858
 859         r = sd_bus_message_read(reply,
 860                                 "soshusub",
 861                                 &id,
 862                                 &object_path,
 863                                 &runtime_path,
 864                                 &session_fd,
 865                                 &original_uid,
 866                                 &seat,
 867                                 &vtnr,
 868                                 &existing);
 869         if (r < 0)
 870                 return pam_bus_log_parse_error(handle, r);
 871
 872         if (debug)
 873                 pam_syslog(handle, LOG_DEBUG, "Reply from logind: "
 874                            "id=%s object_path=%s runtime_path=%s session_fd=%d seat=%s vtnr=%u original_uid=%u",
 875                            id, object_path, runtime_path, session_fd, seat, vtnr, original_uid);
 876
 877         r = update_environment(handle, "XDG_SESSION_ID", id);
 878         if (r != PAM_SUCCESS)
 879                 return r;
 880
 881         if (original_uid == ur->uid) {
 882                 /* Don't set $XDG_RUNTIME_DIR if the user we now
 883                  * authenticated for does not match the original user
 884                  * of the session. We do this in order not to result
 885                  * in privileged apps clobbering the runtime directory
 886                  * unnecessarily. */
 887
 888                 if (validate_runtime_directory(handle, runtime_path, ur->uid)) {
 889                         r = update_environment(handle, "XDG_RUNTIME_DIR", runtime_path);
 890                         if (r != PAM_SUCCESS)
 891                                 return r;
 892                 }
 893
 894                 r = export_legacy_dbus_address(handle, ur->uid, runtime_path);
 895                 if (r != PAM_SUCCESS)
 896                         return r;
 897         }
 898
 899         /* Most likely we got the session/type/class from environment variables, but might have gotten the data
 900          * somewhere else (for example PAM module parameters). Let's now update the environment variables, so that this
 901          * data is inherited into the session processes, and programs can rely on them to be initialized. */
 902
 903         r = update_environment(handle, "XDG_SESSION_TYPE", type);
 904         if (r != PAM_SUCCESS)
 905                 return r;
 906
 907         r = update_environment(handle, "XDG_SESSION_CLASS", class);
 908         if (r != PAM_SUCCESS)
 909                 return r;
 910
 911         r = update_environment(handle, "XDG_SESSION_DESKTOP", desktop);
 912         if (r != PAM_SUCCESS)
 913                 return r;
 914
 915         r = update_environment(handle, "XDG_SEAT", seat);
 916         if (r != PAM_SUCCESS)
 917                 return r;
 918
 919         if (vtnr > 0) {
 920                 char buf[DECIMAL_STR_MAX(vtnr)];
 921                 sprintf(buf, "%u", vtnr);
 922
 923                 r = update_environment(handle, "XDG_VTNR", buf);
 924                 if (r != PAM_SUCCESS)
 925                         return r;
 926         }
 927
 928         r = pam_set_data(handle, "systemd.existing", INT_TO_PTR(!!existing), NULL);
 929         if (r != PAM_SUCCESS) {
 930                 pam_syslog(handle, LOG_ERR, "Failed to install existing flag: %s", pam_strerror(handle, r));
 931                 return r;
 932         }
 933
 934         if (session_fd >= 0) {
 935                 session_fd = fcntl(session_fd, F_DUPFD_CLOEXEC, 3);
 936                 if (session_fd < 0) {
 937                         pam_syslog(handle, LOG_ERR, "Failed to dup session fd: %m");
 938                         return PAM_SESSION_ERR;
 939                 }
 940
 941                 r = pam_set_data(handle, "systemd.session-fd", FD_TO_PTR(session_fd), NULL);
 942                 if (r != PAM_SUCCESS) {
 943                         pam_syslog(handle, LOG_ERR, "Failed to install session fd: %s", pam_strerror(handle, r));
 944                         safe_close(session_fd);
 945                         return r;
 946                 }
 947         }
 948
 949         r = apply_user_record_settings(handle, ur, debug);
 950         if (r != PAM_SUCCESS)
 951                 return r;
 952
 953         /* Let's release the D-Bus connection, after all the session might live quite a long time, and we are
 954          * not going to use the bus connection in that time, so let's better close before the daemon kicks us
 955          * off because we are not processing anything. */
 956         (void) pam_release_bus_connection(handle);
 957         return PAM_SUCCESS;
 958 }
 959
 960 _public_ PAM_EXTERN int pam_sm_close_session(
 961                 pam_handle_t *handle,
 962                 int flags,
 963                 int argc, const char **argv) {
 964
 965         const void *existing = NULL;
 966         const char *id;
 967         int r;
 968
 969         assert(handle);
 970
 971         /* Only release session if it wasn't pre-existing when we
 972          * tried to create it */
 973         (void) pam_get_data(handle, "systemd.existing", &existing);
 974
 975         id = pam_getenv(handle, "XDG_SESSION_ID");
 976         if (id && !existing) {
 977                 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 978                 _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
 979
 980                 /* Before we go and close the FIFO we need to tell logind that this is a clean session
 981                  * shutdown, so that it doesn't just go and slaughter us immediately after closing the fd */
 982
 983                 r = pam_acquire_bus_connection(handle, &bus);
 984                 if (r != PAM_SUCCESS)
 985                         return r;
 986
 987                 r = sd_bus_call_method(bus,
 988                                        "org.freedesktop.login1",
 989                                        "/org/freedesktop/login1",
 990                                        "org.freedesktop.login1.Manager",
 991                                        "ReleaseSession",
 992                                        &error,
 993                                        NULL,
 994                                        "s",
 995                                        id);
 996                 if (r < 0) {
 997                         pam_syslog(handle, LOG_ERR, "Failed to release session: %s", bus_error_message(&error, r));
 998                         return PAM_SESSION_ERR;
 999                 }
1000         }
1001
1002         /* Note that we are knowingly leaking the FIFO fd here. This way, logind can watch us die. If we
1003          * closed it here it would not have any clue when that is completed. Given that one cannot really
1004          * have multiple PAM sessions open from the same process this means we will leak one FD at max. */
1005
1006         return PAM_SUCCESS;
1007 }