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
  14 #include "alloc-util.h"
  15 #include "audit-util.h"
  16 #include "bus-common-errors.h"
  17 #include "bus-error.h"
  18 #include "bus-util.h"
  19 #include "cgroup-util.h"
  20 #include "def.h"
  21 #include "fd-util.h"
  22 #include "fileio.h"
  23 #include "format-util.h"
  24 #include "hostname-util.h"
  25 #include "login-util.h"
  26 #include "macro.h"
  27 #include "parse-util.h"
  28 #include "path-util.h"
  29 #include "process-util.h"
  30 #include "socket-util.h"
  31 #include "strv.h"
  32 #include "terminal-util.h"
  33 #include "util.h"
  34
  35 static int parse_argv(
  36                 pam_handle_t *handle,
  37                 int argc, const char **argv,
  38                 const char **class,
  39                 const char **type,
  40                 const char **desktop,
  41                 bool *debug) {
  42
  43         unsigned i;
  44
  45         assert(argc >= 0);
  46         assert(argc == 0 || argv);
  47
  48         for (i = 0; i < (unsigned) argc; i++) {
  49                 if (startswith(argv[i], "class=")) {
  50                         if (class)
  51                                 *class = argv[i] + 6;
  52
  53                 } else if (startswith(argv[i], "type=")) {
  54                         if (type)
  55                                 *type = argv[i] + 5;
  56
  57                 } else if (startswith(argv[i], "desktop=")) {
  58                         if (desktop)
  59                                 *desktop = argv[i] + 8;
  60
  61                 } else if (streq(argv[i], "debug")) {
  62                         if (debug)
  63                                 *debug = true;
  64
  65                 } else if (startswith(argv[i], "debug=")) {
  66                         int k;
  67
  68                         k = parse_boolean(argv[i] + 6);
  69                         if (k < 0)
  70                                 pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring.");
  71                         else if (debug)
  72                                 *debug = k;
  73
  74                 } else
  75                         pam_syslog(handle, LOG_WARNING, "Unknown parameter '%s', ignoring", argv[i]);
  76         }
  77
  78         return 0;
  79 }
  80
  81 static int get_user_data(
  82                 pam_handle_t *handle,
  83                 const char **ret_username,
  84                 struct passwd **ret_pw) {
  85
  86         const char *username = NULL;
  87         struct passwd *pw = NULL;
  88         int r;
  89
  90         assert(handle);
  91         assert(ret_username);
  92         assert(ret_pw);
  93
  94         r = pam_get_user(handle, &username, NULL);
  95         if (r != PAM_SUCCESS) {
  96                 pam_syslog(handle, LOG_ERR, "Failed to get user name.");
  97                 return r;
  98         }
  99
 100         if (isempty(username)) {
 101                 pam_syslog(handle, LOG_ERR, "User name not valid.");
 102                 return PAM_AUTH_ERR;
 103         }
 104
 105         pw = pam_modutil_getpwnam(handle, username);
 106         if (!pw) {
 107                 pam_syslog(handle, LOG_ERR, "Failed to get user data.");
 108                 return PAM_USER_UNKNOWN;
 109         }
 110
 111         *ret_pw = pw;
 112         *ret_username = username;
 113
 114         return PAM_SUCCESS;
 115 }
 116
 117 static int socket_from_display(const char *display, char **path) {
 118         size_t k;
 119         char *f, *c;
 120
 121         assert(display);
 122         assert(path);
 123
 124         if (!display_is_local(display))
 125                 return -EINVAL;
 126
 127         k = strspn(display+1, "0123456789");
 128
 129         f = new(char, STRLEN("/tmp/.X11-unix/X") + k + 1);
 130         if (!f)
 131                 return -ENOMEM;
 132
 133         c = stpcpy(f, "/tmp/.X11-unix/X");
 134         memcpy(c, display+1, k);
 135         c[k] = 0;
 136
 137         *path = f;
 138
 139         return 0;
 140 }
 141
 142 static int get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) {
 143         union sockaddr_union sa = {};
 144         _cleanup_free_ char *p = NULL, *tty = NULL;
 145         _cleanup_close_ int fd = -1;
 146         struct ucred ucred;
 147         int v, r, salen;
 148
 149         assert(display);
 150         assert(vtnr);
 151
 152         /* We deduce the X11 socket from the display name, then use
 153          * SO_PEERCRED to determine the X11 server process, ask for
 154          * the controlling tty of that and if it's a VC then we know
 155          * the seat and the virtual terminal. Sounds ugly, is only
 156          * semi-ugly. */
 157
 158         r = socket_from_display(display, &p);
 159         if (r < 0)
 160                 return r;
 161         salen = sockaddr_un_set_path(&sa.un, p);
 162         if (salen < 0)
 163                 return salen;
 164
 165         fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
 166         if (fd < 0)
 167                 return -errno;
 168
 169         if (connect(fd, &sa.sa, salen) < 0)
 170                 return -errno;
 171
 172         r = getpeercred(fd, &ucred);
 173         if (r < 0)
 174                 return r;
 175
 176         r = get_ctty(ucred.pid, NULL, &tty);
 177         if (r < 0)
 178                 return r;
 179
 180         v = vtnr_from_tty(tty);
 181         if (v < 0)
 182                 return v;
 183         else if (v == 0)
 184                 return -ENOENT;
 185
 186         if (seat)
 187                 *seat = "seat0";
 188         *vtnr = (uint32_t) v;
 189
 190         return 0;
 191 }
 192
 193 static int append_session_memory_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 194         uint64_t val;
 195         int r;
 196
 197         if (isempty(limit))
 198                 return 0;
 199
 200         if (streq(limit, "infinity")) {
 201                 r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", (uint64_t)-1);
 202                 if (r < 0) {
 203                         pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror(-r));
 204                         return r;
 205                 }
 206         } else {
 207                 r = parse_permille(limit);
 208                 if (r >= 0) {
 209                         r = sd_bus_message_append(m, "(sv)", "MemoryMaxScale", "u", (uint32_t) (((uint64_t) r * UINT32_MAX) / 1000U));
 210                         if (r < 0) {
 211                                 pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror(-r));
 212                                 return r;
 213                         }
 214                 } else {
 215                         r = parse_size(limit, 1024, &val);
 216                         if (r >= 0) {
 217                                 r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", val);
 218                                 if (r < 0) {
 219                                         pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror(-r));
 220                                         return r;
 221                                 }
 222                         } else
 223                                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.limit: %s, ignoring.", limit);
 224                 }
 225         }
 226
 227         return 0;
 228 }
 229
 230 static int append_session_tasks_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 231         uint64_t val;
 232         int r;
 233
 234         /* No need to parse "infinity" here, it will be set unconditionally later in manager_start_scope() */
 235         if (isempty(limit) || streq(limit, "infinity"))
 236                 return 0;
 237
 238         r = safe_atou64(limit, &val);
 239         if (r >= 0) {
 240                 r = sd_bus_message_append(m, "(sv)", "TasksMax", "t", val);
 241                 if (r < 0) {
 242                         pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror(-r));
 243                         return r;
 244                 }
 245         } else
 246                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.limit: %s, ignoring.", limit);
 247
 248         return 0;
 249 }
 250
 251 static int append_session_cg_weight(pam_handle_t *handle, sd_bus_message *m, const char *limit, const char *field) {
 252         uint64_t val;
 253         int r;
 254
 255         if (isempty(limit))
 256                 return 0;
 257
 258         r = cg_weight_parse(limit, &val);
 259         if (r >= 0) {
 260                 r = sd_bus_message_append(m, "(sv)", field, "t", val);
 261                 if (r < 0) {
 262                         pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror(-r));
 263                         return r;
 264                 }
 265         } else if (streq(field, "CPUWeight"))
 266                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.cpu_weight: %s, ignoring.", limit);
 267         else
 268                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.io_weight: %s, ignoring.", limit);
 269
 270         return 0;
 271 }
 272
 273 static const char* getenv_harder(pam_handle_t *handle, const char *key, const char *fallback) {
 274         const char *v;
 275
 276         assert(handle);
 277         assert(key);
 278
 279         /* Looks for an environment variable, preferrably in the environment block associated with the specified PAM
 280          * handle, falling back to the process' block instead. */
 281
 282         v = pam_getenv(handle, key);
 283         if (!isempty(v))
 284                 return v;
 285
 286         v = getenv(key);
 287         if (!isempty(v))
 288                 return v;
 289
 290         return fallback;
 291 }
 292
 293 static int update_environment(pam_handle_t *handle, const char *key, const char *value) {
 294         int r;
 295
 296         assert(handle);
 297         assert(key);
 298
 299         /* Updates the environment, but only if there's actually a value set. Also, log about errors */
 300
 301         if (isempty(value))
 302                 return PAM_SUCCESS;
 303
 304         r = pam_misc_setenv(handle, key, value, 0);
 305         if (r != PAM_SUCCESS)
 306                 pam_syslog(handle, LOG_ERR, "Failed to set environment variable %s.", key);
 307
 308         return r;
 309 }
 310
 311 static bool validate_runtime_directory(pam_handle_t *handle, const char *path, uid_t uid) {
 312         struct stat st;
 313
 314         assert(path);
 315
 316         /* Just some extra paranoia: let's not set $XDG_RUNTIME_DIR if the directory we'd set it to isn't actually set
 317          * up properly for us. */
 318
 319         if (lstat(path, &st) < 0) {
 320                 pam_syslog(handle, LOG_ERR, "Failed to stat() runtime directory '%s': %s", path, strerror(errno));
 321                 goto fail;
 322         }
 323
 324         if (!S_ISDIR(st.st_mode)) {
 325                 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not actually a directory.", path);
 326                 goto fail;
 327         }
 328
 329         if (st.st_uid != uid) {
 330                 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not owned by UID " UID_FMT ", as it should.", path, uid);
 331                 goto fail;
 332         }
 333
 334         return true;
 335
 336 fail:
 337         pam_syslog(handle, LOG_WARNING, "Not setting $XDG_RUNTIME_DIR, as the directory is not in order.");
 338         return false;
 339 }
 340
 341 _public_ PAM_EXTERN int pam_sm_open_session(
 342                 pam_handle_t *handle,
 343                 int flags,
 344                 int argc, const char **argv) {
 345
 346         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 347         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
 348         const char
 349                 *username, *id, *object_path, *runtime_path,
 350                 *service = NULL,
 351                 *tty = NULL, *display = NULL,
 352                 *remote_user = NULL, *remote_host = NULL,
 353                 *seat = NULL,
 354                 *type = NULL, *class = NULL,
 355                 *class_pam = NULL, *type_pam = NULL, *cvtnr = NULL, *desktop = NULL, *desktop_pam = NULL,
 356                 *memory_max = NULL, *tasks_max = NULL, *cpu_weight = NULL, *io_weight = NULL;
 357         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
 358         int session_fd = -1, existing, r;
 359         bool debug = false, remote;
 360         struct passwd *pw;
 361         uint32_t vtnr = 0;
 362         uid_t original_uid;
 363
 364         assert(handle);
 365
 366         /* Make this a NOP on non-logind systems */
 367         if (!logind_running())
 368                 return PAM_SUCCESS;
 369
 370         if (parse_argv(handle,
 371                        argc, argv,
 372                        &class_pam,
 373                        &type_pam,
 374                        &desktop_pam,
 375                        &debug) < 0)
 376                 return PAM_SESSION_ERR;
 377
 378         if (debug)
 379                 pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing");
 380
 381         r = get_user_data(handle, &username, &pw);
 382         if (r != PAM_SUCCESS) {
 383                 pam_syslog(handle, LOG_ERR, "Failed to get user data.");
 384                 return r;
 385         }
 386
 387         /* Make sure we don't enter a loop by talking to
 388          * systemd-logind when it is actually waiting for the
 389          * background to finish start-up. If the service is
 390          * "systemd-user" we simply set XDG_RUNTIME_DIR and
 391          * leave. */
 392
 393         pam_get_item(handle, PAM_SERVICE, (const void**) &service);
 394         if (streq_ptr(service, "systemd-user")) {
 395                 _cleanup_free_ char *rt = NULL;
 396
 397                 if (asprintf(&rt, "/run/user/"UID_FMT, pw->pw_uid) < 0)
 398                         return PAM_BUF_ERR;
 399
 400                 if (validate_runtime_directory(handle, rt, pw->pw_uid)) {
 401                         r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
 402                         if (r != PAM_SUCCESS) {
 403                                 pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
 404                                 return r;
 405                         }
 406                 }
 407
 408                 return PAM_SUCCESS;
 409         }
 410
 411         /* Otherwise, we ask logind to create a session for us */
 412
 413         pam_get_item(handle, PAM_XDISPLAY, (const void**) &display);
 414         pam_get_item(handle, PAM_TTY, (const void**) &tty);
 415         pam_get_item(handle, PAM_RUSER, (const void**) &remote_user);
 416         pam_get_item(handle, PAM_RHOST, (const void**) &remote_host);
 417
 418         seat = getenv_harder(handle, "XDG_SEAT", NULL);
 419         cvtnr = getenv_harder(handle, "XDG_VTNR", NULL);
 420         type = getenv_harder(handle, "XDG_SESSION_TYPE", type_pam);
 421         class = getenv_harder(handle, "XDG_SESSION_CLASS", class_pam);
 422         desktop = getenv_harder(handle, "XDG_SESSION_DESKTOP", desktop_pam);
 423
 424         tty = strempty(tty);
 425
 426         if (strchr(tty, ':')) {
 427                 /* A tty with a colon is usually an X11 display, placed there to show up in utmp. We rearrange things
 428                  * and don't pretend that an X display was a tty. */
 429                 if (isempty(display))
 430                         display = tty;
 431                 tty = NULL;
 432
 433         } else if (streq(tty, "cron")) {
 434                 /* cron is setting PAM_TTY to "cron" for some reason (the commit carries no information why, but
 435                  * probably because it wants to set it to something as pam_time/pam_access/… require PAM_TTY to be set
 436                  * (as they otherwise even try to update it!) — but cron doesn't actually allocate a TTY for its forked
 437                  * off processes.) */
 438                 type = "unspecified";
 439                 class = "background";
 440                 tty = NULL;
 441
 442         } else if (streq(tty, "ssh")) {
 443                 /* ssh has been setting PAM_TTY to "ssh" (for the same reason as cron does this, see above. For further
 444                  * details look for "PAM_TTY_KLUDGE" in the openssh sources). */
 445                 type ="tty";
 446                 class = "user";
 447                 tty = NULL; /* This one is particularly sad, as this means that ssh sessions — even though usually
 448                              * associated with a pty — won't be tracked by their tty in logind. This is because ssh
 449                              * does the PAM session registration early for new connections, and registers a pty only
 450                              * much later (this is because it doesn't know yet if it needs one at all, as whether to
 451                              * register a pty or not is negotiated much later in the protocol). */
 452
 453         } else
 454                 /* Chop off leading /dev prefix that some clients specify, but others do not. */
 455                 tty = skip_dev_prefix(tty);
 456
 457         /* If this fails vtnr will be 0, that's intended */
 458         if (!isempty(cvtnr))
 459                 (void) safe_atou32(cvtnr, &vtnr);
 460
 461         if (!isempty(display) && !vtnr) {
 462                 if (isempty(seat))
 463                         (void) get_seat_from_display(display, &seat, &vtnr);
 464                 else if (streq(seat, "seat0"))
 465                         (void) get_seat_from_display(display, NULL, &vtnr);
 466         }
 467
 468         if (seat && !streq(seat, "seat0") && vtnr != 0) {
 469                 pam_syslog(handle, LOG_DEBUG, "Ignoring vtnr %"PRIu32" for %s which is not seat0", vtnr, seat);
 470                 vtnr = 0;
 471         }
 472
 473         if (isempty(type))
 474                 type = !isempty(display) ? "x11" :
 475                            !isempty(tty) ? "tty" : "unspecified";
 476
 477         if (isempty(class))
 478                 class = streq(type, "unspecified") ? "background" : "user";
 479
 480         remote = !isempty(remote_host) && !is_localhost(remote_host);
 481
 482         (void) pam_get_data(handle, "systemd.memory_max", (const void **)&memory_max);
 483         (void) pam_get_data(handle, "systemd.tasks_max",  (const void **)&tasks_max);
 484         (void) pam_get_data(handle, "systemd.cpu_weight", (const void **)&cpu_weight);
 485         (void) pam_get_data(handle, "systemd.io_weight",  (const void **)&io_weight);
 486
 487         /* Talk to logind over the message bus */
 488
 489         r = sd_bus_open_system(&bus);
 490         if (r < 0) {
 491                 pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", strerror(-r));
 492                 return PAM_SESSION_ERR;
 493         }
 494
 495         if (debug) {
 496                 pam_syslog(handle, LOG_DEBUG, "Asking logind to create session: "
 497                            "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",
 498                            pw->pw_uid, getpid_cached(),
 499                            strempty(service),
 500                            type, class, strempty(desktop),
 501                            strempty(seat), vtnr, strempty(tty), strempty(display),
 502                            yes_no(remote), strempty(remote_user), strempty(remote_host));
 503                 pam_syslog(handle, LOG_DEBUG, "Session limits: "
 504                            "memory_max=%s tasks_max=%s cpu_weight=%s io_weight=%s",
 505                            strna(memory_max), strna(tasks_max), strna(cpu_weight), strna(io_weight));
 506         }
 507
 508         r = sd_bus_message_new_method_call(
 509                         bus,
 510                         &m,
 511                         "org.freedesktop.login1",
 512                         "/org/freedesktop/login1",
 513                         "org.freedesktop.login1.Manager",
 514                         "CreateSession");
 515         if (r < 0) {
 516                 pam_syslog(handle, LOG_ERR, "Failed to create CreateSession method call: %s", strerror(-r));
 517                 return PAM_SESSION_ERR;
 518         }
 519
 520         r = sd_bus_message_append(m, "uusssssussbss",
 521                         (uint32_t) pw->pw_uid,
 522                         0,
 523                         service,
 524                         type,
 525                         class,
 526                         desktop,
 527                         seat,
 528                         vtnr,
 529                         tty,
 530                         display,
 531                         remote,
 532                         remote_user,
 533                         remote_host);
 534         if (r < 0) {
 535                 pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror(-r));
 536                 return PAM_SESSION_ERR;
 537         }
 538
 539         r = sd_bus_message_open_container(m, 'a', "(sv)");
 540         if (r < 0) {
 541                 pam_syslog(handle, LOG_ERR, "Failed to open message container: %s", strerror(-r));
 542                 return PAM_SYSTEM_ERR;
 543         }
 544
 545         r = append_session_memory_max(handle, m, memory_max);
 546         if (r < 0)
 547                 return PAM_SESSION_ERR;
 548
 549         r = append_session_tasks_max(handle, m, tasks_max);
 550         if (r < 0)
 551                 return PAM_SESSION_ERR;
 552
 553         r = append_session_cg_weight(handle, m, cpu_weight, "CPUWeight");
 554         if (r < 0)
 555                 return PAM_SESSION_ERR;
 556
 557         r = append_session_cg_weight(handle, m, io_weight, "IOWeight");
 558         if (r < 0)
 559                 return PAM_SESSION_ERR;
 560
 561         r = sd_bus_message_close_container(m);
 562         if (r < 0) {
 563                 pam_syslog(handle, LOG_ERR, "Failed to close message container: %s", strerror(-r));
 564                 return PAM_SYSTEM_ERR;
 565         }
 566
 567         r = sd_bus_call(bus, m, 0, &error, &reply);
 568         if (r < 0) {
 569                 if (sd_bus_error_has_name(&error, BUS_ERROR_SESSION_BUSY)) {
 570                         pam_syslog(handle, LOG_DEBUG, "Cannot create session: %s", bus_error_message(&error, r));
 571                         return PAM_SUCCESS;
 572                 } else {
 573                         pam_syslog(handle, LOG_ERR, "Failed to create session: %s", bus_error_message(&error, r));
 574                         return PAM_SYSTEM_ERR;
 575                 }
 576         }
 577
 578         r = sd_bus_message_read(reply,
 579                                 "soshusub",
 580                                 &id,
 581                                 &object_path,
 582                                 &runtime_path,
 583                                 &session_fd,
 584                                 &original_uid,
 585                                 &seat,
 586                                 &vtnr,
 587                                 &existing);
 588         if (r < 0) {
 589                 pam_syslog(handle, LOG_ERR, "Failed to parse message: %s", strerror(-r));
 590                 return PAM_SESSION_ERR;
 591         }
 592
 593         if (debug)
 594                 pam_syslog(handle, LOG_DEBUG, "Reply from logind: "
 595                            "id=%s object_path=%s runtime_path=%s session_fd=%d seat=%s vtnr=%u original_uid=%u",
 596                            id, object_path, runtime_path, session_fd, seat, vtnr, original_uid);
 597
 598         r = update_environment(handle, "XDG_SESSION_ID", id);
 599         if (r != PAM_SUCCESS)
 600                 return r;
 601
 602         if (original_uid == pw->pw_uid) {
 603                 /* Don't set $XDG_RUNTIME_DIR if the user we now
 604                  * authenticated for does not match the original user
 605                  * of the session. We do this in order not to result
 606                  * in privileged apps clobbering the runtime directory
 607                  * unnecessarily. */
 608
 609                 if (validate_runtime_directory(handle, runtime_path, pw->pw_uid)) {
 610                         r = update_environment(handle, "XDG_RUNTIME_DIR", runtime_path);
 611                         if (r != PAM_SUCCESS)
 612                                 return r;
 613                 }
 614         }
 615
 616         /* Most likely we got the session/type/class from environment variables, but might have gotten the data
 617          * somewhere else (for example PAM module parameters). Let's now update the environment variables, so that this
 618          * data is inherited into the session processes, and programs can rely on them to be initialized. */
 619
 620         r = update_environment(handle, "XDG_SESSION_TYPE", type);
 621         if (r != PAM_SUCCESS)
 622                 return r;
 623
 624         r = update_environment(handle, "XDG_SESSION_CLASS", class);
 625         if (r != PAM_SUCCESS)
 626                 return r;
 627
 628         r = update_environment(handle, "XDG_SESSION_DESKTOP", desktop);
 629         if (r != PAM_SUCCESS)
 630                 return r;
 631
 632         r = update_environment(handle, "XDG_SEAT", seat);
 633         if (r != PAM_SUCCESS)
 634                 return r;
 635
 636         if (vtnr > 0) {
 637                 char buf[DECIMAL_STR_MAX(vtnr)];
 638                 sprintf(buf, "%u", vtnr);
 639
 640                 r = update_environment(handle, "XDG_VTNR", buf);
 641                 if (r != PAM_SUCCESS)
 642                         return r;
 643         }
 644
 645         r = pam_set_data(handle, "systemd.existing", INT_TO_PTR(!!existing), NULL);
 646         if (r != PAM_SUCCESS) {
 647                 pam_syslog(handle, LOG_ERR, "Failed to install existing flag.");
 648                 return r;
 649         }
 650
 651         if (session_fd >= 0) {
 652                 session_fd = fcntl(session_fd, F_DUPFD_CLOEXEC, 3);
 653                 if (session_fd < 0) {
 654                         pam_syslog(handle, LOG_ERR, "Failed to dup session fd: %m");
 655                         return PAM_SESSION_ERR;
 656                 }
 657
 658                 r = pam_set_data(handle, "systemd.session-fd", FD_TO_PTR(session_fd), NULL);
 659                 if (r != PAM_SUCCESS) {
 660                         pam_syslog(handle, LOG_ERR, "Failed to install session fd.");
 661                         safe_close(session_fd);
 662                         return r;
 663                 }
 664         }
 665
 666         return PAM_SUCCESS;
 667 }
 668
 669 _public_ PAM_EXTERN int pam_sm_close_session(
 670                 pam_handle_t *handle,
 671                 int flags,
 672                 int argc, const char **argv) {
 673
 674         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 675         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
 676         const void *existing = NULL;
 677         const char *id;
 678         int r;
 679
 680         assert(handle);
 681
 682         /* Only release session if it wasn't pre-existing when we
 683          * tried to create it */
 684         (void) pam_get_data(handle, "systemd.existing", &existing);
 685
 686         id = pam_getenv(handle, "XDG_SESSION_ID");
 687         if (id && !existing) {
 688
 689                 /* Before we go and close the FIFO we need to tell
 690                  * logind that this is a clean session shutdown, so
 691                  * that it doesn't just go and slaughter us
 692                  * immediately after closing the fd */
 693
 694                 r = sd_bus_open_system(&bus);
 695                 if (r < 0) {
 696                         pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", strerror(-r));
 697                         return PAM_SESSION_ERR;
 698                 }
 699
 700                 r = sd_bus_call_method(bus,
 701                                        "org.freedesktop.login1",
 702                                        "/org/freedesktop/login1",
 703                                        "org.freedesktop.login1.Manager",
 704                                        "ReleaseSession",
 705                                        &error,
 706                                        NULL,
 707                                        "s",
 708                                        id);
 709                 if (r < 0) {
 710                         pam_syslog(handle, LOG_ERR, "Failed to release session: %s", bus_error_message(&error, r));
 711                         return PAM_SESSION_ERR;
 712                 }
 713         }
 714
 715         /* Note that we are knowingly leaking the FIFO fd here. This
 716          * way, logind can watch us die. If we closed it here it would
 717          * not have any clue when that is completed. Given that one
 718          * cannot really have multiple PAM sessions open from the same
 719          * process this means we will leak one FD at max. */
 720
 721         return PAM_SUCCESS;
 722 }