src/login/pam_systemd.c

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