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