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 "parse-util.h"
  32 #include "path-util.h"
  33 #include "process-util.h"
  34 #include "socket-util.h"
  35 #include "stdio-util.h"
  36 #include "strv.h"
  37 #include "terminal-util.h"
  38
  39 #define LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC (2*USEC_PER_MINUTE)
  40
  41 static int parse_argv(
  42                 pam_handle_t *handle,
  43                 int argc, const char **argv,
  44                 const char **class,
  45                 const char **type,
  46                 const char **desktop,
  47                 bool *debug) {
  48
  49         unsigned i;
  50
  51         assert(argc >= 0);
  52         assert(argc == 0 || argv);
  53
  54         for (i = 0; i < (unsigned) argc; i++) {
  55                 const char *p;
  56
  57                 if ((p = startswith(argv[i], "class="))) {
  58                         if (class)
  59                                 *class = p;
  60
  61                 } else if ((p = startswith(argv[i], "type="))) {
  62                         if (type)
  63                                 *type = p;
  64
  65                 } else if ((p = startswith(argv[i], "desktop="))) {
  66                         if (desktop)
  67                                 *desktop = p;
  68
  69                 } else if (streq(argv[i], "debug")) {
  70                         if (debug)
  71                                 *debug = true;
  72
  73                 } else if ((p = startswith(argv[i], "debug="))) {
  74                         int k;
  75
  76                         k = parse_boolean(p);
  77                         if (k < 0)
  78                                 pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring: %s", p);
  79                         else if (debug)
  80                                 *debug = k;
  81
  82                 } else
  83                         pam_syslog(handle, LOG_WARNING, "Unknown parameter '%s', ignoring", argv[i]);
  84         }
  85
  86         return 0;
  87 }
  88
  89 static int get_user_data(
  90                 pam_handle_t *handle,
  91                 const char **ret_username,
  92                 struct passwd **ret_pw) {
  93
  94         const char *username = NULL;
  95         struct passwd *pw = NULL;
  96         int r;
  97
  98         assert(handle);
  99         assert(ret_username);
 100         assert(ret_pw);
 101
 102         r = pam_get_user(handle, &username, NULL);
 103         if (r != PAM_SUCCESS) {
 104                 pam_syslog(handle, LOG_ERR, "Failed to get user name: %s", pam_strerror(handle, r));
 105                 return r;
 106         }
 107
 108         if (isempty(username)) {
 109                 pam_syslog(handle, LOG_ERR, "User name not valid.");
 110                 return PAM_AUTH_ERR;
 111         }
 112
 113         pw = pam_modutil_getpwnam(handle, username);
 114         if (!pw) {
 115                 pam_syslog(handle, LOG_ERR, "Failed to get user data.");
 116                 return PAM_USER_UNKNOWN;
 117         }
 118
 119         *ret_pw = pw;
 120         *ret_username = username;
 121
 122         return PAM_SUCCESS;
 123 }
 124
 125 static bool display_is_local(const char *display) {
 126         assert(display);
 127
 128         return
 129                 display[0] == ':' &&
 130                 display[1] >= '0' &&
 131                 display[1] <= '9';
 132 }
 133
 134 static int socket_from_display(const char *display, char **path) {
 135         size_t k;
 136         char *f, *c;
 137
 138         assert(display);
 139         assert(path);
 140
 141         if (!display_is_local(display))
 142                 return -EINVAL;
 143
 144         k = strspn(display+1, "0123456789");
 145
 146         f = new(char, STRLEN("/tmp/.X11-unix/X") + k + 1);
 147         if (!f)
 148                 return -ENOMEM;
 149
 150         c = stpcpy(f, "/tmp/.X11-unix/X");
 151         memcpy(c, display+1, k);
 152         c[k] = 0;
 153
 154         *path = f;
 155
 156         return 0;
 157 }
 158
 159 static int get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) {
 160         union sockaddr_union sa = {};
 161         _cleanup_free_ char *p = NULL, *tty = NULL;
 162         _cleanup_close_ int fd = -1;
 163         struct ucred ucred;
 164         int v, r, salen;
 165
 166         assert(display);
 167         assert(vtnr);
 168
 169         /* We deduce the X11 socket from the display name, then use
 170          * SO_PEERCRED to determine the X11 server process, ask for
 171          * the controlling tty of that and if it's a VC then we know
 172          * the seat and the virtual terminal. Sounds ugly, is only
 173          * semi-ugly. */
 174
 175         r = socket_from_display(display, &p);
 176         if (r < 0)
 177                 return r;
 178         salen = sockaddr_un_set_path(&sa.un, p);
 179         if (salen < 0)
 180                 return salen;
 181
 182         fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
 183         if (fd < 0)
 184                 return -errno;
 185
 186         if (connect(fd, &sa.sa, salen) < 0)
 187                 return -errno;
 188
 189         r = getpeercred(fd, &ucred);
 190         if (r < 0)
 191                 return r;
 192
 193         r = get_ctty(ucred.pid, NULL, &tty);
 194         if (r < 0)
 195                 return r;
 196
 197         v = vtnr_from_tty(tty);
 198         if (v < 0)
 199                 return v;
 200         else if (v == 0)
 201                 return -ENOENT;
 202
 203         if (seat)
 204                 *seat = "seat0";
 205         *vtnr = (uint32_t) v;
 206
 207         return 0;
 208 }
 209
 210 static int export_legacy_dbus_address(
 211                 pam_handle_t *handle,
 212                 uid_t uid,
 213                 const char *runtime) {
 214
 215         const char *s;
 216         _cleanup_free_ char *t = NULL;
 217         int r = PAM_BUF_ERR;
 218
 219         /* We need to export $DBUS_SESSION_BUS_ADDRESS because various applications will not connect
 220          * correctly to the bus without it. This setting matches what dbus.socket does for the user
 221          * session using 'systemctl --user set-environment'. We want to have the same configuration
 222          * in processes started from the PAM session.
 223          *
 224          * The setting of the address is guarded by the access() check because it is also possible to compile
 225          * dbus without --enable-user-session, in which case this socket is not used, and
 226          * $DBUS_SESSION_BUS_ADDRESS should not be set. An alternative approach would to not do the access()
 227          * check here, and let applications try on their own, by using "unix:path=%s/bus;autolaunch:". But we
 228          * expect the socket to be present by the time we do this check, so we can just as well check once
 229          * here. */
 230
 231         s = strjoina(runtime, "/bus");
 232         if (access(s, F_OK) < 0)
 233                 return PAM_SUCCESS;
 234
 235         if (asprintf(&t, DEFAULT_USER_BUS_ADDRESS_FMT, runtime) < 0)
 236                 goto error;
 237
 238         r = pam_misc_setenv(handle, "DBUS_SESSION_BUS_ADDRESS", t, 0);
 239         if (r != PAM_SUCCESS)
 240                 goto error;
 241
 242         return PAM_SUCCESS;
 243
 244 error:
 245         pam_syslog(handle, LOG_ERR, "Failed to set bus variable.");
 246         return r;
 247 }
 248
 249 static int append_session_memory_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 250         uint64_t val;
 251         int r;
 252
 253         if (isempty(limit))
 254                 return 0;
 255
 256         if (streq(limit, "infinity")) {
 257                 r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", (uint64_t)-1);
 258                 if (r < 0) {
 259                         pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror_safe(r));
 260                         return r;
 261                 }
 262         } else {
 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                                 pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror_safe(r));
 268                                 return r;
 269                         }
 270                 } else {
 271                         r = parse_size(limit, 1024, &val);
 272                         if (r >= 0) {
 273                                 r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", val);
 274                                 if (r < 0) {
 275                                         pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror_safe(r));
 276                                         return r;
 277                                 }
 278                         } else
 279                                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.memory_max: %s, ignoring.", limit);
 280                 }
 281         }
 282
 283         return 0;
 284 }
 285
 286 static int append_session_runtime_max_sec(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 287         usec_t val;
 288         int r;
 289
 290         /* No need to parse "infinity" here, it will be set by default later in scope_init() */
 291         if (isempty(limit) || streq(limit, "infinity"))
 292                 return 0;
 293
 294         r = parse_sec(limit, &val);
 295         if (r >= 0) {
 296                 r = sd_bus_message_append(m, "(sv)", "RuntimeMaxUSec", "t", (uint64_t) val);
 297                 if (r < 0) {
 298                         pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror_safe(r));
 299                         return r;
 300                 }
 301         } else
 302                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.runtime_max_sec: %s, ignoring.", limit);
 303
 304         return 0;
 305 }
 306
 307 static int append_session_tasks_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
 308         uint64_t val;
 309         int r;
 310
 311         /* No need to parse "infinity" here, it will be set unconditionally later in manager_start_scope() */
 312         if (isempty(limit) || streq(limit, "infinity"))
 313                 return 0;
 314
 315         r = safe_atou64(limit, &val);
 316         if (r >= 0) {
 317                 r = sd_bus_message_append(m, "(sv)", "TasksMax", "t", val);
 318                 if (r < 0) {
 319                         pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror_safe(r));
 320                         return r;
 321                 }
 322         } else
 323                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.tasks_max: %s, ignoring.", limit);
 324
 325         return 0;
 326 }
 327
 328 static int append_session_cg_weight(pam_handle_t *handle, sd_bus_message *m, const char *limit, const char *field) {
 329         uint64_t val;
 330         int r;
 331
 332         if (isempty(limit))
 333                 return 0;
 334
 335         r = cg_weight_parse(limit, &val);
 336         if (r >= 0) {
 337                 r = sd_bus_message_append(m, "(sv)", field, "t", val);
 338                 if (r < 0) {
 339                         pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror_safe(r));
 340                         return r;
 341                 }
 342         } else if (streq(field, "CPUWeight"))
 343                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.cpu_weight: %s, ignoring.", limit);
 344         else
 345                 pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.io_weight: %s, ignoring.", limit);
 346
 347         return 0;
 348 }
 349
 350 static const char* getenv_harder(pam_handle_t *handle, const char *key, const char *fallback) {
 351         const char *v;
 352
 353         assert(handle);
 354         assert(key);
 355
 356         /* Looks for an environment variable, preferably in the environment block associated with the
 357          * specified PAM handle, falling back to the process' block instead. Why check both? Because we want
 358          * to permit configuration of session properties from unit files that invoke PAM services, so that
 359          * PAM services don't have to be reworked to set systemd-specific properties, but these properties
 360          * can still be set from the unit file Environment= block. */
 361
 362         v = pam_getenv(handle, key);
 363         if (!isempty(v))
 364                 return v;
 365
 366         /* We use secure_getenv() here, since we might get loaded into su/sudo, which are SUID. Ideally
 367          * they'd clean up the environment before invoking foreign code (such as PAM modules), but alas they
 368          * currently don't (to be precise, they clean up the environment they pass to their children, but
 369          * not their own environ[]). */
 370         v = secure_getenv(key);
 371         if (!isempty(v))
 372                 return v;
 373
 374         return fallback;
 375 }
 376
 377 static int update_environment(pam_handle_t *handle, const char *key, const char *value) {
 378         int r;
 379
 380         assert(handle);
 381         assert(key);
 382
 383         /* Updates the environment, but only if there's actually a value set. Also, log about errors */
 384
 385         if (isempty(value))
 386                 return PAM_SUCCESS;
 387
 388         r = pam_misc_setenv(handle, key, value, 0);
 389         if (r != PAM_SUCCESS)
 390                 pam_syslog(handle, LOG_ERR, "Failed to set environment variable %s: %s", key, pam_strerror(handle, r));
 391
 392         return r;
 393 }
 394
 395 static bool validate_runtime_directory(pam_handle_t *handle, const char *path, uid_t uid) {
 396         struct stat st;
 397
 398         assert(handle);
 399         assert(path);
 400
 401         /* Just some extra paranoia: let's not set $XDG_RUNTIME_DIR if the directory we'd set it to isn't actually set
 402          * up properly for us. */
 403
 404         if (lstat(path, &st) < 0) {
 405                 pam_syslog(handle, LOG_ERR, "Failed to stat() runtime directory '%s': %s", path, strerror_safe(errno));
 406                 goto fail;
 407         }
 408
 409         if (!S_ISDIR(st.st_mode)) {
 410                 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not actually a directory.", path);
 411                 goto fail;
 412         }
 413
 414         if (st.st_uid != uid) {
 415                 pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not owned by UID " UID_FMT ", as it should.", path, uid);
 416                 goto fail;
 417         }
 418
 419         return true;
 420
 421 fail:
 422         pam_syslog(handle, LOG_WARNING, "Not setting $XDG_RUNTIME_DIR, as the directory is not in order.");
 423         return false;
 424 }
 425
 426 _public_ PAM_EXTERN int pam_sm_open_session(
 427                 pam_handle_t *handle,
 428                 int flags,
 429                 int argc, const char **argv) {
 430
 431         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 432         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
 433         const char
 434                 *username, *id, *object_path, *runtime_path,
 435                 *service = NULL,
 436                 *tty = NULL, *display = NULL,
 437                 *remote_user = NULL, *remote_host = NULL,
 438                 *seat = NULL,
 439                 *type = NULL, *class = NULL,
 440                 *class_pam = NULL, *type_pam = NULL, *cvtnr = NULL, *desktop = NULL, *desktop_pam = NULL,
 441                 *memory_max = NULL, *tasks_max = NULL, *cpu_weight = NULL, *io_weight = NULL, *runtime_max_sec = NULL;
 442         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
 443         int session_fd = -1, existing, r;
 444         bool debug = false, remote;
 445         struct passwd *pw;
 446         uint32_t vtnr = 0;
 447         uid_t original_uid;
 448
 449         assert(handle);
 450
 451         /* Make this a NOP on non-logind systems */
 452         if (!logind_running())
 453                 return PAM_SUCCESS;
 454
 455         if (parse_argv(handle,
 456                        argc, argv,
 457                        &class_pam,
 458                        &type_pam,
 459                        &desktop_pam,
 460                        &debug) < 0)
 461                 return PAM_SESSION_ERR;
 462
 463         if (debug)
 464                 pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing");
 465
 466         r = get_user_data(handle, &username, &pw);
 467         if (r != PAM_SUCCESS)
 468                 return r;
 469
 470         /* Make sure we don't enter a loop by talking to
 471          * systemd-logind when it is actually waiting for the
 472          * background to finish start-up. If the service is
 473          * "systemd-user" we simply set XDG_RUNTIME_DIR and
 474          * leave. */
 475
 476         (void) pam_get_item(handle, PAM_SERVICE, (const void**) &service);
 477         if (streq_ptr(service, "systemd-user")) {
 478                 char rt[STRLEN("/run/user/") + DECIMAL_STR_MAX(uid_t)];
 479
 480                 xsprintf(rt, "/run/user/"UID_FMT, pw->pw_uid);
 481                 if (validate_runtime_directory(handle, rt, pw->pw_uid)) {
 482                         r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
 483                         if (r != PAM_SUCCESS) {
 484                                 pam_syslog(handle, LOG_ERR, "Failed to set runtime dir: %s", pam_strerror(handle, r));
 485                                 return r;
 486                         }
 487                 }
 488
 489                 r = export_legacy_dbus_address(handle, pw->pw_uid, rt);
 490                 if (r != PAM_SUCCESS)
 491                         return r;
 492
 493                 return PAM_SUCCESS;
 494         }
 495
 496         /* Otherwise, we ask logind to create a session for us */
 497
 498         (void) pam_get_item(handle, PAM_XDISPLAY, (const void**) &display);
 499         (void) pam_get_item(handle, PAM_TTY, (const void**) &tty);
 500         (void) pam_get_item(handle, PAM_RUSER, (const void**) &remote_user);
 501         (void) pam_get_item(handle, PAM_RHOST, (const void**) &remote_host);
 502
 503         seat = getenv_harder(handle, "XDG_SEAT", NULL);
 504         cvtnr = getenv_harder(handle, "XDG_VTNR", NULL);
 505         type = getenv_harder(handle, "XDG_SESSION_TYPE", type_pam);
 506         class = getenv_harder(handle, "XDG_SESSION_CLASS", class_pam);
 507         desktop = getenv_harder(handle, "XDG_SESSION_DESKTOP", desktop_pam);
 508
 509         tty = strempty(tty);
 510
 511         if (strchr(tty, ':')) {
 512                 /* A tty with a colon is usually an X11 display, placed there to show up in utmp. We rearrange things
 513                  * and don't pretend that an X display was a tty. */
 514                 if (isempty(display))
 515                         display = tty;
 516                 tty = NULL;
 517
 518         } else if (streq(tty, "cron")) {
 519                 /* cron is setting PAM_TTY to "cron" for some reason (the commit carries no information why, but
 520                  * probably because it wants to set it to something as pam_time/pam_access/… require PAM_TTY to be set
 521                  * (as they otherwise even try to update it!) — but cron doesn't actually allocate a TTY for its forked
 522                  * off processes.) */
 523                 type = "unspecified";
 524                 class = "background";
 525                 tty = NULL;
 526
 527         } else if (streq(tty, "ssh")) {
 528                 /* ssh has been setting PAM_TTY to "ssh" (for the same reason as cron does this, see above. For further
 529                  * details look for "PAM_TTY_KLUDGE" in the openssh sources). */
 530                 type ="tty";
 531                 class = "user";
 532                 tty = NULL; /* This one is particularly sad, as this means that ssh sessions — even though usually
 533                              * associated with a pty — won't be tracked by their tty in logind. This is because ssh
 534                              * does the PAM session registration early for new connections, and registers a pty only
 535                              * much later (this is because it doesn't know yet if it needs one at all, as whether to
 536                              * register a pty or not is negotiated much later in the protocol). */
 537
 538         } else
 539                 /* Chop off leading /dev prefix that some clients specify, but others do not. */
 540                 tty = skip_dev_prefix(tty);
 541
 542         /* If this fails vtnr will be 0, that's intended */
 543         if (!isempty(cvtnr))
 544                 (void) safe_atou32(cvtnr, &vtnr);
 545
 546         if (!isempty(display) && !vtnr) {
 547                 if (isempty(seat))
 548                         (void) get_seat_from_display(display, &seat, &vtnr);
 549                 else if (streq(seat, "seat0"))
 550                         (void) get_seat_from_display(display, NULL, &vtnr);
 551         }
 552
 553         if (seat && !streq(seat, "seat0") && vtnr != 0) {
 554                 if (debug)
 555                         pam_syslog(handle, LOG_DEBUG, "Ignoring vtnr %"PRIu32" for %s which is not seat0", vtnr, seat);
 556                 vtnr = 0;
 557         }
 558
 559         if (isempty(type))
 560                 type = !isempty(display) ? "x11" :
 561                            !isempty(tty) ? "tty" : "unspecified";
 562
 563         if (isempty(class))
 564                 class = streq(type, "unspecified") ? "background" : "user";
 565
 566         remote = !isempty(remote_host) && !is_localhost(remote_host);
 567
 568         (void) pam_get_data(handle, "systemd.memory_max", (const void **)&memory_max);
 569         (void) pam_get_data(handle, "systemd.tasks_max",  (const void **)&tasks_max);
 570         (void) pam_get_data(handle, "systemd.cpu_weight", (const void **)&cpu_weight);
 571         (void) pam_get_data(handle, "systemd.io_weight",  (const void **)&io_weight);
 572         (void) pam_get_data(handle, "systemd.runtime_max_sec", (const void **)&runtime_max_sec);
 573
 574         /* Talk to logind over the message bus */
 575
 576         r = sd_bus_open_system(&bus);
 577         if (r < 0) {
 578                 pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", strerror_safe(r));
 579                 return PAM_SESSION_ERR;
 580         }
 581
 582         if (debug) {
 583                 pam_syslog(handle, LOG_DEBUG, "Asking logind to create session: "
 584                            "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",
 585                            pw->pw_uid, getpid_cached(),
 586                            strempty(service),
 587                            type, class, strempty(desktop),
 588                            strempty(seat), vtnr, strempty(tty), strempty(display),
 589                            yes_no(remote), strempty(remote_user), strempty(remote_host));
 590                 pam_syslog(handle, LOG_DEBUG, "Session limits: "
 591                            "memory_max=%s tasks_max=%s cpu_weight=%s io_weight=%s runtime_max_sec=%s",
 592                            strna(memory_max), strna(tasks_max), strna(cpu_weight), strna(io_weight), strna(runtime_max_sec));
 593         }
 594
 595         r = sd_bus_message_new_method_call(
 596                         bus,
 597                         &m,
 598                         "org.freedesktop.login1",
 599                         "/org/freedesktop/login1",
 600                         "org.freedesktop.login1.Manager",
 601                         "CreateSession");
 602         if (r < 0) {
 603                 pam_syslog(handle, LOG_ERR, "Failed to create CreateSession method call: %s", strerror_safe(r));
 604                 return PAM_SESSION_ERR;
 605         }
 606
 607         r = sd_bus_message_append(m, "uusssssussbss",
 608                         (uint32_t) pw->pw_uid,
 609                         0,
 610                         service,
 611                         type,
 612                         class,
 613                         desktop,
 614                         seat,
 615                         vtnr,
 616                         tty,
 617                         display,
 618                         remote,
 619                         remote_user,
 620                         remote_host);
 621         if (r < 0) {
 622                 pam_syslog(handle, LOG_ERR, "Failed to append to bus message: %s", strerror_safe(r));
 623                 return PAM_SESSION_ERR;
 624         }
 625
 626         r = sd_bus_message_open_container(m, 'a', "(sv)");
 627         if (r < 0) {
 628                 pam_syslog(handle, LOG_ERR, "Failed to open message container: %s", strerror_safe(r));
 629                 return PAM_SYSTEM_ERR;
 630         }
 631
 632         r = append_session_memory_max(handle, m, memory_max);
 633         if (r < 0)
 634                 return PAM_SESSION_ERR;
 635
 636         r = append_session_runtime_max_sec(handle, m, runtime_max_sec);
 637         if (r < 0)
 638                 return PAM_SESSION_ERR;
 639
 640         r = append_session_tasks_max(handle, m, tasks_max);
 641         if (r < 0)
 642                 return PAM_SESSION_ERR;
 643
 644         r = append_session_cg_weight(handle, m, cpu_weight, "CPUWeight");
 645         if (r < 0)
 646                 return PAM_SESSION_ERR;
 647
 648         r = append_session_cg_weight(handle, m, io_weight, "IOWeight");
 649         if (r < 0)
 650                 return PAM_SESSION_ERR;
 651
 652         r = sd_bus_message_close_container(m);
 653         if (r < 0) {
 654                 pam_syslog(handle, LOG_ERR, "Failed to close message container: %s", strerror_safe(r));
 655                 return PAM_SYSTEM_ERR;
 656         }
 657
 658         r = sd_bus_call(bus, m, LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC, &error, &reply);
 659         if (r < 0) {
 660                 if (sd_bus_error_has_name(&error, BUS_ERROR_SESSION_BUSY)) {
 661                         if (debug)
 662                                 pam_syslog(handle, LOG_DEBUG, "Not creating session: %s", bus_error_message(&error, r));
 663                         return PAM_SUCCESS;
 664                 } else {
 665                         pam_syslog(handle, LOG_ERR, "Failed to create session: %s", bus_error_message(&error, r));
 666                         return PAM_SESSION_ERR;
 667                 }
 668         }
 669
 670         r = sd_bus_message_read(reply,
 671                                 "soshusub",
 672                                 &id,
 673                                 &object_path,
 674                                 &runtime_path,
 675                                 &session_fd,
 676                                 &original_uid,
 677                                 &seat,
 678                                 &vtnr,
 679                                 &existing);
 680         if (r < 0) {
 681                 pam_syslog(handle, LOG_ERR, "Failed to parse message: %s", strerror_safe(r));
 682                 return PAM_SESSION_ERR;
 683         }
 684
 685         if (debug)
 686                 pam_syslog(handle, LOG_DEBUG, "Reply from logind: "
 687                            "id=%s object_path=%s runtime_path=%s session_fd=%d seat=%s vtnr=%u original_uid=%u",
 688                            id, object_path, runtime_path, session_fd, seat, vtnr, original_uid);
 689
 690         r = update_environment(handle, "XDG_SESSION_ID", id);
 691         if (r != PAM_SUCCESS)
 692                 return r;
 693
 694         if (original_uid == pw->pw_uid) {
 695                 /* Don't set $XDG_RUNTIME_DIR if the user we now
 696                  * authenticated for does not match the original user
 697                  * of the session. We do this in order not to result
 698                  * in privileged apps clobbering the runtime directory
 699                  * unnecessarily. */
 700
 701                 if (validate_runtime_directory(handle, runtime_path, pw->pw_uid)) {
 702                         r = update_environment(handle, "XDG_RUNTIME_DIR", runtime_path);
 703                         if (r != PAM_SUCCESS)
 704                                 return r;
 705                 }
 706
 707                 r = export_legacy_dbus_address(handle, pw->pw_uid, runtime_path);
 708                 if (r != PAM_SUCCESS)
 709                         return r;
 710         }
 711
 712         /* Most likely we got the session/type/class from environment variables, but might have gotten the data
 713          * somewhere else (for example PAM module parameters). Let's now update the environment variables, so that this
 714          * data is inherited into the session processes, and programs can rely on them to be initialized. */
 715
 716         r = update_environment(handle, "XDG_SESSION_TYPE", type);
 717         if (r != PAM_SUCCESS)
 718                 return r;
 719
 720         r = update_environment(handle, "XDG_SESSION_CLASS", class);
 721         if (r != PAM_SUCCESS)
 722                 return r;
 723
 724         r = update_environment(handle, "XDG_SESSION_DESKTOP", desktop);
 725         if (r != PAM_SUCCESS)
 726                 return r;
 727
 728         r = update_environment(handle, "XDG_SEAT", seat);
 729         if (r != PAM_SUCCESS)
 730                 return r;
 731
 732         if (vtnr > 0) {
 733                 char buf[DECIMAL_STR_MAX(vtnr)];
 734                 sprintf(buf, "%u", vtnr);
 735
 736                 r = update_environment(handle, "XDG_VTNR", buf);
 737                 if (r != PAM_SUCCESS)
 738                         return r;
 739         }
 740
 741         r = pam_set_data(handle, "systemd.existing", INT_TO_PTR(!!existing), NULL);
 742         if (r != PAM_SUCCESS) {
 743                 pam_syslog(handle, LOG_ERR, "Failed to install existing flag: %s", pam_strerror(handle, r));
 744                 return r;
 745         }
 746
 747         if (session_fd >= 0) {
 748                 session_fd = fcntl(session_fd, F_DUPFD_CLOEXEC, 3);
 749                 if (session_fd < 0) {
 750                         pam_syslog(handle, LOG_ERR, "Failed to dup session fd: %m");
 751                         return PAM_SESSION_ERR;
 752                 }
 753
 754                 r = pam_set_data(handle, "systemd.session-fd", FD_TO_PTR(session_fd), NULL);
 755                 if (r != PAM_SUCCESS) {
 756                         pam_syslog(handle, LOG_ERR, "Failed to install session fd: %s", pam_strerror(handle, r));
 757                         safe_close(session_fd);
 758                         return r;
 759                 }
 760         }
 761
 762         return PAM_SUCCESS;
 763 }
 764
 765 _public_ PAM_EXTERN int pam_sm_close_session(
 766                 pam_handle_t *handle,
 767                 int flags,
 768                 int argc, const char **argv) {
 769
 770         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 771         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
 772         const void *existing = NULL;
 773         const char *id;
 774         int r;
 775
 776         assert(handle);
 777
 778         /* Only release session if it wasn't pre-existing when we
 779          * tried to create it */
 780         (void) pam_get_data(handle, "systemd.existing", &existing);
 781
 782         id = pam_getenv(handle, "XDG_SESSION_ID");
 783         if (id && !existing) {
 784
 785                 /* Before we go and close the FIFO we need to tell
 786                  * logind that this is a clean session shutdown, so
 787                  * that it doesn't just go and slaughter us
 788                  * immediately after closing the fd */
 789
 790                 r = sd_bus_open_system(&bus);
 791                 if (r < 0) {
 792                         pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", strerror_safe(r));
 793                         return PAM_SESSION_ERR;
 794                 }
 795
 796                 r = sd_bus_call_method(bus,
 797                                        "org.freedesktop.login1",
 798                                        "/org/freedesktop/login1",
 799                                        "org.freedesktop.login1.Manager",
 800                                        "ReleaseSession",
 801                                        &error,
 802                                        NULL,
 803                                        "s",
 804                                        id);
 805                 if (r < 0) {
 806                         pam_syslog(handle, LOG_ERR, "Failed to release session: %s", bus_error_message(&error, r));
 807                         return PAM_SESSION_ERR;
 808                 }
 809         }
 810
 811         /* Note that we are knowingly leaking the FIFO fd here. This
 812          * way, logind can watch us die. If we closed it here it would
 813          * not have any clue when that is completed. Given that one
 814          * cannot really have multiple PAM sessions open from the same
 815          * process this means we will leak one FD at max. */
 816
 817         return PAM_SUCCESS;
 818 }