src/login/pam_systemd.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <endian.h>
   4 #include <errno.h>
   5 #include <fcntl.h>
   6 #include <pwd.h>
   7 #include <security/_pam_macros.h>
   8 #include <security/pam_ext.h>
   9 #include <security/pam_misc.h>
  10 #include <security/pam_modules.h>
  11 #include <security/pam_modutil.h>
  12 #include <sys/file.h>
  13 #include <sys/stat.h>
  14 #include <sys/types.h>
  15 #include <unistd.h>
  16
  17 #include "alloc-util.h"
  18 #include "audit-util.h"
  19 #include "bus-common-errors.h"
  20 #include "bus-error.h"
  21 #include "bus-internal.h"
  22 #include "bus-util.h"
  23 #include "cgroup-setup.h"
  24 #include "errno-util.h"
  25 #include "fd-util.h"
  26 #include "fileio.h"
  27 #include "format-util.h"
  28 #include "hostname-util.h"
  29 #include "login-util.h"
  30 #include "macro.h"
  31 #include "pam-util.h"
  32 #include "parse-util.h"
  33 #include "path-util.h"
  34 #include "process-util.h"
  35 #include "socket-util.h"
  36 #include "stdio-util.h"
  37 #include "strv.h"
  38 #include "terminal-util.h"
  39
  40 #define LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC (2*USEC_PER_MINUTE)
  41
  42 static int parse_argv(
  43                 pam_handle_t *handle,
  44                 int argc, const char **argv,
  45                 const char **class,
  46                 const char **type,
  47                 const char **desktop,
  48                 bool *debug) {
  49
  50         unsigned i;
  51
  52         assert(argc >= 0);
  53         assert(argc == 0 || argv);
  54
  55         for (i = 0; i < (unsigned) argc; i++) {
  56                 const char *p;
  57
  58                 if ((p = startswith(argv[i], "class="))) {
  59                         if (class)
  60                                 *class = p;
  61
  62                 } else if ((p = startswith(argv[i], "type="))) {
  63                         if (type)
  64                                 *type = p;
  65
  66                 } else if ((p = startswith(argv[i], "desktop="))) {
  67                         if (desktop)
  68                                 *desktop = p;
  69
  70                 } else if (streq(argv[i], "debug")) {
  71                         if (debug)
  72                                 *debug = true;
  73
  74                 } else if ((p = startswith(argv[i], "debug="))) {
  75                         int k;
  76
  77                         k = parse_boolean(p);
  78                         if (k < 0)
  79                                 pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring: %s", p);
  80                         else if (debug)
  81                                 *debug = k;
  82
  83                 } else
  84                         pam_syslog(handle, LOG_WARNING, "Unknown parameter '%s', ignoring", argv[i]);
  85         }
  86
  87         return 0;
  88 }
  89
  90 static int get_user_data(
  91                 pam_handle_t *handle,
  92                 const char **ret_username,
  93                 struct passwd **ret_pw) {
  94
  95         const char *username = NULL;
  96         struct passwd *pw = NULL;
  97         int r;
  98
  99         assert(handle);
 100         assert(ret_username);
 101         assert(ret_pw);
 102
 103         r = pam_get_user(handle, &username, NULL);
 104         if (r != PAM_SUCCESS) {
 105                 pam_syslog(handle, LOG_ERR, "Failed to get user name: %s", pam_strerror(handle, r));
 106                 return r;
 107         }
 108
 109         if (isempty(username)) {
 110                 pam_syslog(handle, LOG_ERR, "User name not valid.");
 111                 return PAM_AUTH_ERR;
 112         }
 113
 114         pw = pam_modutil_getpwnam(handle, username);
 115         if (!pw) {
 116                 pam_syslog(handle, LOG_ERR, "Failed to get user data.");
 117                 return PAM_USER_UNKNOWN;
 118         }
 119
 120         *ret_pw = pw;
 121         *ret_username = username;
 122
 123         return PAM_SUCCESS;
 124 }
 125
 126 static bool display_is_local(const char *display) {
 127         assert(display);
 128
 129         return
 130                 display[0] == ':' &&
 131                 display[1] >= '0' &&
 132                 display[1] <= '9';
 133 }
 134
 135 static int socket_from_display(const char *display, char **path) {
 136         size_t k;
 137         char *f, *c;
 138
 139         assert(display);
 140         assert(path);
 141
 142         if (!display_is_local(display))
 143                 return -EINVAL;
 144
 145         k = strspn(display+1, "0123456789");
 146
 147         f = new(char, STRLEN("/tmp/.X11-unix/X") + k + 1);
 148         if (!f)
 149                 return -ENOMEM;
 150
 151         c = stpcpy(f, "/tmp/.X11-unix/X");
 152         memcpy(c, display+1, k);
 153         c[k] = 0;
 154
 155         *path = f;
 156
 157         return 0;
 158 }
 159
 160 static int get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) {
 161         union sockaddr_union sa = {};
 162         _cleanup_free_ char *p = NULL, *tty = NULL;
 163         _cleanup_close_ int fd = -1;
 164         struct ucred ucred;
 165         int v, r, salen;
 166
 167         assert(display);
 168         assert(vtnr);
 169
 170         /* We deduce the X11 socket from the display name, then use
 171          * SO_PEERCRED to determine the X11 server process, ask for
 172          * the controlling tty of that and if it's a VC then we know
 173          * the seat and the virtual terminal. Sounds ugly, is only
 174          * semi-ugly. */
 175
 176         r = socket_from_display(display, &p);
 177         if (r < 0)
 178                 return r;
 179         salen = sockaddr_un_set_path(&sa.un, p);
 180         if (salen < 0)
 181                 return salen;
 182
 183         fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
 184         if (fd < 0)
 185                 return -errno;
 186
 187         if (connect(fd, &sa.sa, salen) < 0)
 188                 return -errno;
 189
 190         r = getpeercred(fd, &ucred);
 191         if (r < 0)
 192                 return r;
 193
 194         r = get_ctty(ucred.pid, NULL, &tty);
 195         if (r < 0)
 196                 return r;
 197
 198         v = vtnr_from_tty(tty);
 199         if (v < 0)
 200                 return v;
 201         else if (v == 0)
 202                 return -ENOENT;
 203
 204         if (seat)
 205                 *seat = "seat0";
 206         *vtnr = (uint32_t) v;
 207
 208         return 0;
 209 }
 210
 211 static int export_legacy_dbus_address(
 212                 pam_handle_t *handle,
 213                 uid_t uid,
 214                 const char *runtime) {
 215
 216         const char *s;
 217         _cleanup_free_ char *t = NULL;
 218         int r = PAM_BUF_ERR;
 219
 220         /* We need to export $DBUS_SESSION_BUS_ADDRESS because various applications will not connect
 221          * correctly to the bus without it. This setting matches what dbus.socket does for the user
 222          * session using 'systemctl --user set-environment'. We want to have the same configuration
 223          * in processes started from the PAM session.
 224          *
 225          * The setting of the address is guarded by the access() check because it is also possible to compile
 226          * dbus without --enable-user-session, in which case this socket is not used, and
 227          * $DBUS_SESSION_BUS_ADDRESS should not be set. An alternative approach would to not do the access()
 228          * check here, and let applications try on their own, by using "unix:path=%s/bus;autolaunch:". But we
 229          * expect the socket to be present by the time we do this check, so we can just as well check once
 230          * here. */
 231
 232         s = strjoina(runtime, "/bus");
 233         if (access(s, F_OK) < 0)
 234                 return PAM_SUCCESS;
 235
 236         if (asprintf(&t, DEFAULT_USER_BUS_ADDRESS_FMT, runtime) < 0)
 237                 return pam_log_oom(handle);
 238
 239         r = pam_misc_setenv(handle, "DBUS_SESSION_BUS_ADDRESS", t, 0);
 240         if (r != PAM_SUCCESS) {
 241                 pam_syslog(handle, LOG_ERR, "Failed to set bus variable: %s", pam_strerror(handle, r));
 242                 return r;
 243         }
 244
 245         return PAM_SUCCESS;
 246 }
 247
 248 static int append_session_memory_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 249         uint64_t val;
 250         int r;
 251
 252         if (isempty(limit))
 253                 return 0;
 254
 255         if (streq(limit, "infinity")) {
 256                 r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", (uint64_t)-1);
 257                 if (r < 0)
 258                         return pam_bus_log_create_error(handle, r);
 259
 260                 return 0;
 261         }
 262
 263         r = parse_permille(limit);
 264         if (r >= 0) {
 265                 r = sd_bus_message_append(m, "(sv)", "MemoryMaxScale", "u", (uint32_t) (((uint64_t) r * UINT32_MAX) / 1000U));
 266                 if (r < 0)
 267                         return pam_bus_log_create_error(handle, r);
 268
 269                 return 0;
 270         }
 271
 272         r = parse_size(limit, 1024, &val);
 273         if (r >= 0) {
 274                 r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", val);
 275                 if (r < 0)
 276                         return pam_bus_log_create_error(handle, r);
 277
 278                 return 0;
 279         }
 280
 281         pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.memory_max, ignoring: %s", limit);
 282         return 0;
 283 }
 284
 285 static int append_session_runtime_max_sec(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 286         usec_t val;
 287         int r;
 288
 289         /* No need to parse "infinity" here, it will be set by default later in scope_init() */
 290         if (isempty(limit) || streq(limit, "infinity"))
 291                 return 0;
 292
 293         r = parse_sec(limit, &val);
 294         if (r >= 0) {
 295                 r = sd_bus_message_append(m, "(sv)", "RuntimeMaxUSec", "t", (uint64_t) val);
 296                 if (r < 0) {
 297                         pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror_safe(r));
 298                         return r;
 299                 }
 300         } else
 301                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.runtime_max_sec: %s, ignoring.", limit);
 302
 303         return 0;
 304 }
 305
 306 static int append_session_tasks_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 307         uint64_t val;
 308         int r;
 309
 310         /* No need to parse "infinity" here, it will be set unconditionally later in manager_start_scope() */
 311         if (isempty(limit) || streq(limit, "infinity"))
 312                 return 0;
 313
 314         r = safe_atou64(limit, &val);
 315         if (r >= 0) {
 316                 r = sd_bus_message_append(m, "(sv)", "TasksMax", "t", val);
 317                 if (r < 0)
 318                         return pam_bus_log_create_error(handle, r);
 319         } else
 320                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.tasks_max, ignoring: %s", limit);
 321
 322         return 0;
 323 }
 324
 325 static int append_session_cg_weight(pam_handle_t *handle, sd_bus_message *m, const char *limit, const char *field) {
 326         uint64_t val;
 327         int r;
 328
 329         if (isempty(limit))
 330                 return 0;
 331
 332         r = cg_weight_parse(limit, &val);
 333         if (r >= 0) {
 334                 r = sd_bus_message_append(m, "(sv)", field, "t", val);
 335                 if (r < 0)
 336                         return pam_bus_log_create_error(handle, r);
 337         } else if (streq(field, "CPUWeight"))
 338                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.cpu_weight, ignoring: %s", limit);
 339         else
 340                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.io_weight, ignoring: %s", limit);
 341
 342         return 0;
 343 }
 344
 345 static const char* getenv_harder(pam_handle_t *handle, const char *key, const char *fallback) {
 346         const char *v;
 347
 348         assert(handle);
 349         assert(key);
 350
 351         /* Looks for an environment variable, preferably in the environment block associated with the
 352          * specified PAM handle, falling back to the process' block instead. Why check both? Because we want
 353          * to permit configuration of session properties from unit files that invoke PAM services, so that
 354          * PAM services don't have to be reworked to set systemd-specific properties, but these properties
 355          * can still be set from the unit file Environment= block. */
 356
 357         v = pam_getenv(handle, key);
 358         if (!isempty(v))
 359                 return v;
 360
 361         /* We use secure_getenv() here, since we might get loaded into su/sudo, which are SUID. Ideally
 362          * they'd clean up the environment before invoking foreign code (such as PAM modules), but alas they
 363          * currently don't (to be precise, they clean up the environment they pass to their children, but
 364          * not their own environ[]). */
 365         v = secure_getenv(key);
 366         if (!isempty(v))
 367                 return v;
 368
 369         return fallback;
 370 }
 371
 372 static int update_environment(pam_handle_t *handle, const char *key, const char *value) {
 373         int r;
 374
 375         assert(handle);
 376         assert(key);
 377
 378         /* Updates the environment, but only if there's actually a value set. Also, log about errors */
 379
 380         if (isempty(value))
 381                 return PAM_SUCCESS;
 382
 383         r = pam_misc_setenv(handle, key, value, 0);
 384         if (r != PAM_SUCCESS)
 385                 pam_syslog(handle, LOG_ERR, "Failed to set environment variable %s: %s", key, pam_strerror(handle, r));
 386
 387         return r;
 388 }
 389
 390 static bool validate_runtime_directory(pam_handle_t *handle, const char *path, uid_t uid) {
 391         struct stat st;
 392
 393         assert(handle);
 394         assert(path);
 395
 396         /* Just some extra paranoia: let's not set $XDG_RUNTIME_DIR if the directory we'd set it to isn't actually set
 397          * up properly for us. */
 398
 399         if (lstat(path, &st) < 0) {
 400                 pam_syslog(handle, LOG_ERR, "Failed to stat() runtime directory '%s': %s", path, strerror_safe(errno));
 401                 goto fail;
 402         }
 403
 404         if (!S_ISDIR(st.st_mode)) {
 405                 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not actually a directory.", path);
 406                 goto fail;
 407         }
 408
 409         if (st.st_uid != uid) {
 410                 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not owned by UID " UID_FMT ", as it should.", path, uid);
 411                 goto fail;
 412         }
 413
 414         return true;
 415
 416 fail:
 417         pam_syslog(handle, LOG_WARNING, "Not setting $XDG_RUNTIME_DIR, as the directory is not in order.");
 418         return false;
 419 }
 420
 421 _public_ PAM_EXTERN int pam_sm_open_session(
 422                 pam_handle_t *handle,
 423                 int flags,
 424                 int argc, const char **argv) {
 425
 426         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 427         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
 428         const char
 429                 *username, *id, *object_path, *runtime_path,
 430                 *service = NULL,
 431                 *tty = NULL, *display = NULL,
 432                 *remote_user = NULL, *remote_host = NULL,
 433                 *seat = NULL,
 434                 *type = NULL, *class = NULL,
 435                 *class_pam = NULL, *type_pam = NULL, *cvtnr = NULL, *desktop = NULL, *desktop_pam = NULL,
 436                 *memory_max = NULL, *tasks_max = NULL, *cpu_weight = NULL, *io_weight = NULL, *runtime_max_sec = NULL;
 437         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
 438         int session_fd = -1, existing, r;
 439         bool debug = false, remote;
 440         struct passwd *pw;
 441         uint32_t vtnr = 0;
 442         uid_t original_uid;
 443
 444         assert(handle);
 445
 446         /* Make this a NOP on non-logind systems */
 447         if (!logind_running())
 448                 return PAM_SUCCESS;
 449
 450         if (parse_argv(handle,
 451                        argc, argv,
 452                        &class_pam,
 453                        &type_pam,
 454                        &desktop_pam,
 455                        &debug) < 0)
 456                 return PAM_SESSION_ERR;
 457
 458         if (debug)
 459                 pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing");
 460
 461         r = get_user_data(handle, &username, &pw);
 462         if (r != PAM_SUCCESS)
 463                 return r;
 464
 465         /* Make sure we don't enter a loop by talking to
 466          * systemd-logind when it is actually waiting for the
 467          * background to finish start-up. If the service is
 468          * "systemd-user" we simply set XDG_RUNTIME_DIR and
 469          * leave. */
 470
 471         (void) pam_get_item(handle, PAM_SERVICE, (const void**) &service);
 472         if (streq_ptr(service, "systemd-user")) {
 473                 char rt[STRLEN("/run/user/") + DECIMAL_STR_MAX(uid_t)];
 474
 475                 xsprintf(rt, "/run/user/"UID_FMT, pw->pw_uid);
 476                 if (validate_runtime_directory(handle, rt, pw->pw_uid)) {
 477                         r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
 478                         if (r != PAM_SUCCESS) {
 479                                 pam_syslog(handle, LOG_ERR, "Failed to set runtime dir: %s", pam_strerror(handle, r));
 480                                 return r;
 481                         }
 482                 }
 483
 484                 r = export_legacy_dbus_address(handle, pw->pw_uid, rt);
 485                 if (r != PAM_SUCCESS)
 486                         return r;
 487
 488                 return PAM_SUCCESS;
 489         }
 490
 491         /* Otherwise, we ask logind to create a session for us */
 492
 493         (void) pam_get_item(handle, PAM_XDISPLAY, (const void**) &display);
 494         (void) pam_get_item(handle, PAM_TTY, (const void**) &tty);
 495         (void) pam_get_item(handle, PAM_RUSER, (const void**) &remote_user);
 496         (void) pam_get_item(handle, PAM_RHOST, (const void**) &remote_host);
 497
 498         seat = getenv_harder(handle, "XDG_SEAT", NULL);
 499         cvtnr = getenv_harder(handle, "XDG_VTNR", NULL);
 500         type = getenv_harder(handle, "XDG_SESSION_TYPE", type_pam);
 501         class = getenv_harder(handle, "XDG_SESSION_CLASS", class_pam);
 502         desktop = getenv_harder(handle, "XDG_SESSION_DESKTOP", desktop_pam);
 503
 504         tty = strempty(tty);
 505
 506         if (strchr(tty, ':')) {
 507                 /* A tty with a colon is usually an X11 display, placed there to show up in utmp. We rearrange things
 508                  * and don't pretend that an X display was a tty. */
 509                 if (isempty(display))
 510                         display = tty;
 511                 tty = NULL;
 512
 513         } else if (streq(tty, "cron")) {
 514                 /* cron is setting PAM_TTY to "cron" for some reason (the commit carries no information why, but
 515                  * probably because it wants to set it to something as pam_time/pam_access/… require PAM_TTY to be set
 516                  * (as they otherwise even try to update it!) — but cron doesn't actually allocate a TTY for its forked
 517                  * off processes.) */
 518                 type = "unspecified";
 519                 class = "background";
 520                 tty = NULL;
 521
 522         } else if (streq(tty, "ssh")) {
 523                 /* ssh has been setting PAM_TTY to "ssh" (for the same reason as cron does this, see above. For further
 524                  * details look for "PAM_TTY_KLUDGE" in the openssh sources). */
 525                 type ="tty";
 526                 class = "user";
 527                 tty = NULL; /* This one is particularly sad, as this means that ssh sessions — even though usually
 528                              * associated with a pty — won't be tracked by their tty in logind. This is because ssh
 529                              * does the PAM session registration early for new connections, and registers a pty only
 530                              * much later (this is because it doesn't know yet if it needs one at all, as whether to
 531                              * register a pty or not is negotiated much later in the protocol). */
 532
 533         } else
 534                 /* Chop off leading /dev prefix that some clients specify, but others do not. */
 535                 tty = skip_dev_prefix(tty);
 536
 537         /* If this fails vtnr will be 0, that's intended */
 538         if (!isempty(cvtnr))
 539                 (void) safe_atou32(cvtnr, &vtnr);
 540
 541         if (!isempty(display) && !vtnr) {
 542                 if (isempty(seat))
 543                         (void) get_seat_from_display(display, &seat, &vtnr);
 544                 else if (streq(seat, "seat0"))
 545                         (void) get_seat_from_display(display, NULL, &vtnr);
 546         }
 547
 548         if (seat && !streq(seat, "seat0") && vtnr != 0) {
 549                 if (debug)
 550                         pam_syslog(handle, LOG_DEBUG, "Ignoring vtnr %"PRIu32" for %s which is not seat0", vtnr, seat);
 551                 vtnr = 0;
 552         }
 553
 554         if (isempty(type))
 555                 type = !isempty(display) ? "x11" :
 556                            !isempty(tty) ? "tty" : "unspecified";
 557
 558         if (isempty(class))
 559                 class = streq(type, "unspecified") ? "background" : "user";
 560
 561         remote = !isempty(remote_host) && !is_localhost(remote_host);
 562
 563         (void) pam_get_data(handle, "systemd.memory_max", (const void **)&memory_max);
 564         (void) pam_get_data(handle, "systemd.tasks_max",  (const void **)&tasks_max);
 565         (void) pam_get_data(handle, "systemd.cpu_weight", (const void **)&cpu_weight);
 566         (void) pam_get_data(handle, "systemd.io_weight",  (const void **)&io_weight);
 567         (void) pam_get_data(handle, "systemd.runtime_max_sec", (const void **)&runtime_max_sec);
 568
 569         /* Talk to logind over the message bus */
 570
 571         r = sd_bus_open_system(&bus);
 572         if (r < 0) {
 573                 pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", strerror_safe(r));
 574                 return PAM_SESSION_ERR;
 575         }
 576
 577         if (debug) {
 578                 pam_syslog(handle, LOG_DEBUG, "Asking logind to create session: "
 579                            "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",
 580                            pw->pw_uid, getpid_cached(),
 581                            strempty(service),
 582                            type, class, strempty(desktop),
 583                            strempty(seat), vtnr, strempty(tty), strempty(display),
 584                            yes_no(remote), strempty(remote_user), strempty(remote_host));
 585                 pam_syslog(handle, LOG_DEBUG, "Session limits: "
 586                            "memory_max=%s tasks_max=%s cpu_weight=%s io_weight=%s runtime_max_sec=%s",
 587                            strna(memory_max), strna(tasks_max), strna(cpu_weight), strna(io_weight), strna(runtime_max_sec));
 588         }
 589
 590         r = sd_bus_message_new_method_call(
 591                         bus,
 592                         &m,
 593                         "org.freedesktop.login1",
 594                         "/org/freedesktop/login1",
 595                         "org.freedesktop.login1.Manager",
 596                         "CreateSession");
 597         if (r < 0)
 598                 return pam_bus_log_create_error(handle, r);
 599
 600         r = sd_bus_message_append(m, "uusssssussbss",
 601                         (uint32_t) pw->pw_uid,
 602                         0,
 603                         service,
 604                         type,
 605                         class,
 606                         desktop,
 607                         seat,
 608                         vtnr,
 609                         tty,
 610                         display,
 611                         remote,
 612                         remote_user,
 613                         remote_host);
 614         if (r < 0)
 615                 return pam_bus_log_create_error(handle, r);
 616
 617         r = sd_bus_message_open_container(m, 'a', "(sv)");
 618         if (r < 0)
 619                 return pam_bus_log_create_error(handle, r);
 620
 621         r = append_session_memory_max(handle, m, memory_max);
 622         if (r < 0)
 623                 return PAM_SESSION_ERR;
 624
 625         r = append_session_runtime_max_sec(handle, m, runtime_max_sec);
 626         if (r < 0)
 627                 return PAM_SESSION_ERR;
 628
 629         r = append_session_tasks_max(handle, m, tasks_max);
 630         if (r < 0)
 631                 return PAM_SESSION_ERR;
 632
 633         r = append_session_cg_weight(handle, m, cpu_weight, "CPUWeight");
 634         if (r < 0)
 635                 return PAM_SESSION_ERR;
 636
 637         r = append_session_cg_weight(handle, m, io_weight, "IOWeight");
 638         if (r < 0)
 639                 return PAM_SESSION_ERR;
 640
 641         r = sd_bus_message_close_container(m);
 642         if (r < 0)
 643                 return pam_bus_log_create_error(handle, r);
 644
 645         r = sd_bus_call(bus, m, LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC, &error, &reply);
 646         if (r < 0) {
 647                 if (sd_bus_error_has_name(&error, BUS_ERROR_SESSION_BUSY)) {
 648                         if (debug)
 649                                 pam_syslog(handle, LOG_DEBUG, "Not creating session: %s", bus_error_message(&error, r));
 650                         return PAM_SUCCESS;
 651                 } else {
 652                         pam_syslog(handle, LOG_ERR, "Failed to create session: %s", bus_error_message(&error, r));
 653                         return PAM_SESSION_ERR;
 654                 }
 655         }
 656
 657         r = sd_bus_message_read(reply,
 658                                 "soshusub",
 659                                 &id,
 660                                 &object_path,
 661                                 &runtime_path,
 662                                 &session_fd,
 663                                 &original_uid,
 664                                 &seat,
 665                                 &vtnr,
 666                                 &existing);
 667         if (r < 0)
 668                 return pam_bus_log_parse_error(handle, r);
 669
 670         if (debug)
 671                 pam_syslog(handle, LOG_DEBUG, "Reply from logind: "
 672                            "id=%s object_path=%s runtime_path=%s session_fd=%d seat=%s vtnr=%u original_uid=%u",
 673                            id, object_path, runtime_path, session_fd, seat, vtnr, original_uid);
 674
 675         r = update_environment(handle, "XDG_SESSION_ID", id);
 676         if (r != PAM_SUCCESS)
 677                 return r;
 678
 679         if (original_uid == pw->pw_uid) {
 680                 /* Don't set $XDG_RUNTIME_DIR if the user we now
 681                  * authenticated for does not match the original user
 682                  * of the session. We do this in order not to result
 683                  * in privileged apps clobbering the runtime directory
 684                  * unnecessarily. */
 685
 686                 if (validate_runtime_directory(handle, runtime_path, pw->pw_uid)) {
 687                         r = update_environment(handle, "XDG_RUNTIME_DIR", runtime_path);
 688                         if (r != PAM_SUCCESS)
 689                                 return r;
 690                 }
 691
 692                 r = export_legacy_dbus_address(handle, pw->pw_uid, runtime_path);
 693                 if (r != PAM_SUCCESS)
 694                         return r;
 695         }
 696
 697         /* Most likely we got the session/type/class from environment variables, but might have gotten the data
 698          * somewhere else (for example PAM module parameters). Let's now update the environment variables, so that this
 699          * data is inherited into the session processes, and programs can rely on them to be initialized. */
 700
 701         r = update_environment(handle, "XDG_SESSION_TYPE", type);
 702         if (r != PAM_SUCCESS)
 703                 return r;
 704
 705         r = update_environment(handle, "XDG_SESSION_CLASS", class);
 706         if (r != PAM_SUCCESS)
 707                 return r;
 708
 709         r = update_environment(handle, "XDG_SESSION_DESKTOP", desktop);
 710         if (r != PAM_SUCCESS)
 711                 return r;
 712
 713         r = update_environment(handle, "XDG_SEAT", seat);
 714         if (r != PAM_SUCCESS)
 715                 return r;
 716
 717         if (vtnr > 0) {
 718                 char buf[DECIMAL_STR_MAX(vtnr)];
 719                 sprintf(buf, "%u", vtnr);
 720
 721                 r = update_environment(handle, "XDG_VTNR", buf);
 722                 if (r != PAM_SUCCESS)
 723                         return r;
 724         }
 725
 726         r = pam_set_data(handle, "systemd.existing", INT_TO_PTR(!!existing), NULL);
 727         if (r != PAM_SUCCESS) {
 728                 pam_syslog(handle, LOG_ERR, "Failed to install existing flag: %s", pam_strerror(handle, r));
 729                 return r;
 730         }
 731
 732         if (session_fd >= 0) {
 733                 session_fd = fcntl(session_fd, F_DUPFD_CLOEXEC, 3);
 734                 if (session_fd < 0) {
 735                         pam_syslog(handle, LOG_ERR, "Failed to dup session fd: %m");
 736                         return PAM_SESSION_ERR;
 737                 }
 738
 739                 r = pam_set_data(handle, "systemd.session-fd", FD_TO_PTR(session_fd), NULL);
 740                 if (r != PAM_SUCCESS) {
 741                         pam_syslog(handle, LOG_ERR, "Failed to install session fd: %s", pam_strerror(handle, r));
 742                         safe_close(session_fd);
 743                         return r;
 744                 }
 745         }
 746
 747         return PAM_SUCCESS;
 748 }
 749
 750 _public_ PAM_EXTERN int pam_sm_close_session(
 751                 pam_handle_t *handle,
 752                 int flags,
 753                 int argc, const char **argv) {
 754
 755         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 756         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
 757         const void *existing = NULL;
 758         const char *id;
 759         int r;
 760
 761         assert(handle);
 762
 763         /* Only release session if it wasn't pre-existing when we
 764          * tried to create it */
 765         (void) pam_get_data(handle, "systemd.existing", &existing);
 766
 767         id = pam_getenv(handle, "XDG_SESSION_ID");
 768         if (id && !existing) {
 769
 770                 /* Before we go and close the FIFO we need to tell
 771                  * logind that this is a clean session shutdown, so
 772                  * that it doesn't just go and slaughter us
 773                  * immediately after closing the fd */
 774
 775                 r = sd_bus_open_system(&bus);
 776                 if (r < 0) {
 777                         pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", strerror_safe(r));
 778                         return PAM_SESSION_ERR;
 779                 }
 780
 781                 r = sd_bus_call_method(bus,
 782                                        "org.freedesktop.login1",
 783                                        "/org/freedesktop/login1",
 784                                        "org.freedesktop.login1.Manager",
 785                                        "ReleaseSession",
 786                                        &error,
 787                                        NULL,
 788                                        "s",
 789                                        id);
 790                 if (r < 0) {
 791                         pam_syslog(handle, LOG_ERR, "Failed to release session: %s", bus_error_message(&error, r));
 792                         return PAM_SESSION_ERR;
 793                 }
 794         }
 795
 796         /* Note that we are knowingly leaking the FIFO fd here. This
 797          * way, logind can watch us die. If we closed it here it would
 798          * not have any clue when that is completed. Given that one
 799          * cannot really have multiple PAM sessions open from the same
 800          * process this means we will leak one FD at max. */
 801
 802         return PAM_SUCCESS;
 803 }