src/pam-module.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23 #include <fcntl.h>
  24 #include <sys/file.h>
  25 #include <pwd.h>
  26 #include <endian.h>
  27
  28 #include <security/pam_modules.h>
  29 #include <security/_pam_macros.h>
  30 #include <security/pam_modutil.h>
  31 #include <security/pam_ext.h>
  32 #include <security/pam_misc.h>
  33
  34 #include "util.h"
  35 #include "cgroup-util.h"
  36 #include "macro.h"
  37 #include "sd-daemon.h"
  38 #include "strv.h"
  39
  40 static int parse_argv(pam_handle_t *handle,
  41                       int argc, const char **argv,
  42                       bool *create_session,
  43                       bool *kill_session,
  44                       bool *kill_user,
  45                       char ***controllers,
  46                       char ***reset_controllers,
  47                       char ***kill_only_users,
  48                       char ***kill_exclude_users) {
  49
  50         unsigned i;
  51         bool reset_controller_set = false;
  52         bool kill_exclude_users_set = false;
  53
  54         assert(argc >= 0);
  55         assert(argc == 0 || argv);
  56
  57         for (i = 0; i < (unsigned) argc; i++) {
  58                 int k;
  59
  60                 if (startswith(argv[i], "create-session=")) {
  61                         if ((k = parse_boolean(argv[i] + 15)) < 0) {
  62                                 pam_syslog(handle, LOG_ERR, "Failed to parse create-session= argument.");
  63                                 return k;
  64                         }
  65
  66                         if (create_session)
  67                                 *create_session = k;
  68
  69                 } else if (startswith(argv[i], "kill-session=")) {
  70                         if ((k = parse_boolean(argv[i] + 13)) < 0) {
  71                                 pam_syslog(handle, LOG_ERR, "Failed to parse kill-session= argument.");
  72                                 return k;
  73                         }
  74
  75                         if (kill_session)
  76                                 *kill_session = k;
  77
  78                 } else if (startswith(argv[i], "kill-user=")) {
  79                         if ((k = parse_boolean(argv[i] + 10)) < 0) {
  80                                 pam_syslog(handle, LOG_ERR, "Failed to parse kill-user= argument.");
  81                                 return k;
  82                         }
  83
  84                         if (kill_user)
  85                                 *kill_user = k;
  86
  87                 } else if (startswith(argv[i], "controllers=")) {
  88
  89                         if (controllers) {
  90                                 char **l;
  91
  92                                 if (!(l = strv_split(argv[i] + 12, ","))) {
  93                                         pam_syslog(handle, LOG_ERR, "Out of memory.");
  94                                         return -ENOMEM;
  95                                 }
  96
  97                                 strv_free(*controllers);
  98                                 *controllers = l;
  99                         }
 100
 101                 } else if (startswith(argv[i], "reset-controllers=")) {
 102
 103                         if (reset_controllers) {
 104                                 char **l;
 105
 106                                 if (!(l = strv_split(argv[i] + 18, ","))) {
 107                                         pam_syslog(handle, LOG_ERR, "Out of memory.");
 108                                         return -ENOMEM;
 109                                 }
 110
 111                                 strv_free(*reset_controllers);
 112                                 *reset_controllers = l;
 113                         }
 114
 115                         reset_controller_set = true;
 116
 117                 } else if (startswith(argv[i], "kill-only-users=")) {
 118
 119                         if (kill_only_users) {
 120                                 char **l;
 121
 122                                 if (!(l = strv_split(argv[i] + 16, ","))) {
 123                                         pam_syslog(handle, LOG_ERR, "Out of memory.");
 124                                         return -ENOMEM;
 125                                 }
 126
 127                                 strv_free(*kill_only_users);
 128                                 *kill_only_users = l;
 129                         }
 130
 131                 } else if (startswith(argv[i], "kill-exclude-users=")) {
 132
 133                         if (kill_exclude_users) {
 134                                 char **l;
 135
 136                                 if (!(l = strv_split(argv[i] + 19, ","))) {
 137                                         pam_syslog(handle, LOG_ERR, "Out of memory.");
 138                                         return -ENOMEM;
 139                                 }
 140
 141                                 strv_free(*kill_exclude_users);
 142                                 *kill_exclude_users = l;
 143                         }
 144
 145                         kill_exclude_users_set = true;
 146
 147                 } else {
 148                         pam_syslog(handle, LOG_ERR, "Unknown parameter '%s'.", argv[i]);
 149                         return -EINVAL;
 150                 }
 151         }
 152
 153         if (!reset_controller_set && reset_controllers) {
 154                 char **l;
 155
 156                 if (!(l = strv_new("cpu", NULL))) {
 157                         pam_syslog(handle, LOG_ERR, "Out of memory");
 158                         return -ENOMEM;
 159                 }
 160
 161                 *reset_controllers = l;
 162         }
 163
 164         if (controllers)
 165                 strv_remove(*controllers, "name=systemd");
 166
 167         if (reset_controllers)
 168                 strv_remove(*reset_controllers, "name=systemd");
 169
 170         if (kill_session && *kill_session && kill_user)
 171                 *kill_user = true;
 172
 173         if (!kill_exclude_users_set && kill_exclude_users) {
 174                 char **l;
 175
 176                 if (!(l = strv_new("root", NULL))) {
 177                         pam_syslog(handle, LOG_ERR, "Out of memory");
 178                         return -ENOMEM;
 179                 }
 180
 181                 *kill_exclude_users = l;
 182         }
 183
 184         return 0;
 185 }
 186
 187 static int open_file_and_lock(const char *fn) {
 188         int fd;
 189
 190         assert(fn);
 191
 192         if ((fd = open(fn, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_CREAT, 0600)) < 0)
 193                 return -errno;
 194
 195         /* The BSD socket semantics are a lot nicer than those of
 196          * POSIX locks. Which is why we use flock() here. BSD locking
 197          * does not work across NFS which however is not needed here
 198          * as the filesystems in question should be local, and only
 199          * locally accessible, and most likely even tmpfs. */
 200
 201         if (flock(fd, LOCK_EX) < 0) {
 202                 close_nointr_nofail(fd);
 203                 return -errno;
 204         }
 205
 206         return fd;
 207 }
 208
 209 enum {
 210         SESSION_ID_AUDIT = 'a',
 211         SESSION_ID_COUNTER = 'c',
 212         SESSION_ID_RANDOM = 'r'
 213 };
 214
 215 static uint64_t get_session_id(int *mode) {
 216         char *s;
 217         int fd;
 218
 219         assert(mode);
 220
 221         /* First attempt: let's use the session ID of the audit
 222          * system, if it is available. */
 223         if (read_one_line_file("/proc/self/sessionid", &s) >= 0) {
 224                 uint32_t u;
 225                 int r;
 226
 227                 r = safe_atou32(s, &u);
 228                 free(s);
 229
 230                 if (r >= 0 && u != (uint32_t) -1 && u > 0) {
 231                         *mode = SESSION_ID_AUDIT;
 232                         return (uint64_t) u;
 233                 }
 234         }
 235
 236         /* Second attempt, use our own counter. */
 237         if ((fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-session")) >= 0) {
 238                 uint64_t counter;
 239                 ssize_t r;
 240
 241                 /* We do a bit of endianess swapping here, just to be
 242                  * sure. /run should be machine specific anyway, and
 243                  * even mounted from tmpfs, so this byteswapping
 244                  * should really not be necessary. But then again, you
 245                  * never know, so let's avoid any risk. */
 246
 247                 if (loop_read(fd, &counter, sizeof(counter), false) != sizeof(counter))
 248                         counter = 1;
 249                 else
 250                         counter = le64toh(counter) + 1;
 251
 252                 if (lseek(fd, 0, SEEK_SET) == 0) {
 253                         uint64_t swapped = htole64(counter);
 254
 255                         r = loop_write(fd, &swapped, sizeof(swapped), false);
 256
 257                         if (r != sizeof(swapped))
 258                                 r = -EIO;
 259                 } else
 260                         r = -errno;
 261
 262                 close_nointr_nofail(fd);
 263
 264                 if (r >= 0) {
 265                         *mode = SESSION_ID_COUNTER;
 266                         return counter;
 267                 }
 268         }
 269
 270         *mode = SESSION_ID_RANDOM;
 271
 272         /* Last attempt, pick a random value */
 273         return (uint64_t) random_ull();
 274 }
 275
 276 static int get_user_data(
 277                 pam_handle_t *handle,
 278                 const char **ret_username,
 279                 struct passwd **ret_pw) {
 280
 281         const char *username = NULL;
 282         struct passwd *pw = NULL;
 283         int r;
 284         bool have_loginuid = false;
 285         char *s;
 286
 287         assert(handle);
 288         assert(ret_username);
 289         assert(ret_pw);
 290
 291         if (read_one_line_file("/proc/self/loginuid", &s) >= 0) {
 292                 uint32_t u;
 293
 294                 r = safe_atou32(s, &u);
 295                 free(s);
 296
 297                 if (r >= 0 && u != (uint32_t) -1 && u > 0) {
 298                         have_loginuid = true;
 299                         pw = pam_modutil_getpwuid(handle, u);
 300                 }
 301         }
 302
 303         if (!have_loginuid) {
 304                 if ((r = pam_get_user(handle, &username, NULL)) != PAM_SUCCESS) {
 305                         pam_syslog(handle, LOG_ERR, "Failed to get user name.");
 306                         return r;
 307                 }
 308
 309                 if (!username || !*username) {
 310                         pam_syslog(handle, LOG_ERR, "User name not valid.");
 311                         return PAM_AUTH_ERR;
 312                 }
 313
 314                 pw = pam_modutil_getpwnam(handle, username);
 315         }
 316
 317         if (!pw) {
 318                 pam_syslog(handle, LOG_ERR, "Failed to get user data.");
 319                 return PAM_USER_UNKNOWN;
 320         }
 321
 322         *ret_pw = pw;
 323         *ret_username = username ? username : pw->pw_name;
 324
 325         return PAM_SUCCESS;
 326 }
 327
 328 static int create_user_group(
 329                 pam_handle_t *handle,
 330                 const char *controller,
 331                 const char *group,
 332                 struct passwd *pw,
 333                 bool attach,
 334                 bool remember) {
 335
 336         int r;
 337
 338         assert(handle);
 339         assert(group);
 340
 341         if (attach)
 342                 r = cg_create_and_attach(controller, group, 0);
 343         else
 344                 r = cg_create(controller, group);
 345
 346         if (r < 0) {
 347                 pam_syslog(handle, LOG_ERR, "Failed to create cgroup: %s", strerror(-r));
 348                 return PAM_SESSION_ERR;
 349         }
 350
 351         if (r > 0 && remember) {
 352                 /* Remember that it was us who created this group, and
 353                  * that hence we need to remove it too. This is a
 354                  * protection against removing the cgroup when run
 355                  * recursively. */
 356                 if ((r = pam_set_data(handle, "systemd.created", INT_TO_PTR(1), NULL)) != PAM_SUCCESS) {
 357                         pam_syslog(handle, LOG_ERR, "Failed to install created variable.");
 358                         return r;
 359                 }
 360         }
 361
 362         if ((r = cg_set_task_access(controller, group, 0644, pw->pw_uid, pw->pw_gid)) < 0 ||
 363             (r = cg_set_group_access(controller, group, 0755, pw->pw_uid, pw->pw_gid)) < 0) {
 364                 pam_syslog(handle, LOG_ERR, "Failed to change access modes: %s", strerror(-r));
 365                 return PAM_SESSION_ERR;
 366         }
 367
 368         return PAM_SUCCESS;
 369 }
 370
 371 static int reset_group(
 372                 pam_handle_t *handle,
 373                 const char *controller) {
 374
 375         int r;
 376
 377         assert(handle);
 378
 379         if ((r = cg_attach(controller, "/", 0)) < 0) {
 380                 pam_syslog(handle, LOG_ERR, "Failed to reset cgroup for controller %s: %s", controller, strerror(-r));
 381                 return PAM_SESSION_ERR;
 382         }
 383
 384         return PAM_SUCCESS;
 385 }
 386
 387 _public_ PAM_EXTERN int pam_sm_open_session(
 388                 pam_handle_t *handle,
 389                 int flags,
 390                 int argc, const char **argv) {
 391
 392         const char *username = NULL;
 393         struct passwd *pw;
 394         int r;
 395         char *buf = NULL;
 396         int lock_fd = -1;
 397         bool create_session = true;
 398         char **controllers = NULL, **reset_controllers = NULL, **c;
 399         char *cgroup_user_tree = NULL;
 400
 401         assert(handle);
 402
 403         /* pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing"); */
 404
 405         /* Make this a NOP on non-systemd systems */
 406         if (sd_booted() <= 0)
 407                 return PAM_SUCCESS;
 408
 409         if (parse_argv(handle,
 410                        argc, argv,
 411                        &create_session, NULL, NULL,
 412                        &controllers, &reset_controllers,
 413                        NULL, NULL) < 0)
 414                 return PAM_SESSION_ERR;
 415
 416         if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
 417                 goto finish;
 418
 419         if ((r = cg_get_user_path(&cgroup_user_tree)) < 0) {
 420                 pam_syslog(handle, LOG_ERR, "Failed to determine user cgroup tree: %s", strerror(-r));
 421                 r = PAM_SYSTEM_ERR;
 422                 goto finish;
 423         }
 424
 425         if (safe_mkdir(RUNTIME_DIR "/user", 0755, 0, 0) < 0) {
 426                 pam_syslog(handle, LOG_ERR, "Failed to create runtime directory: %m");
 427                 r = PAM_SYSTEM_ERR;
 428                 goto finish;
 429         }
 430
 431         if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
 432                 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
 433                 r = PAM_SYSTEM_ERR;
 434                 goto finish;
 435         }
 436
 437         /* Create /run/user/$USER */
 438         free(buf);
 439         if (asprintf(&buf, RUNTIME_DIR "/user/%s", username) < 0) {
 440                 r = PAM_BUF_ERR;
 441                 goto finish;
 442         }
 443
 444         if (safe_mkdir(buf, 0700, pw->pw_uid, pw->pw_gid) < 0) {
 445                 pam_syslog(handle, LOG_WARNING, "Failed to create runtime directory: %m");
 446                 r = PAM_SYSTEM_ERR;
 447                 goto finish;
 448         } else if ((r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", buf, 0)) != PAM_SUCCESS) {
 449                 pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
 450                 goto finish;
 451         }
 452
 453         free(buf);
 454         buf = NULL;
 455
 456         if (create_session) {
 457                 const char *id;
 458
 459                 /* Reuse or create XDG session ID */
 460                 if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
 461                         int mode;
 462
 463                         if (asprintf(&buf, "%llux", (unsigned long long) get_session_id(&mode)) < 0) {
 464                                 r = PAM_BUF_ERR;
 465                                 goto finish;
 466                         }
 467
 468                         /* To avoid id clashes we add the session id
 469                          * source to our session ids. Note that the
 470                          * session id source might change during
 471                          * runtime, because a filesystem became
 472                          * writable or the system reconfigured. */
 473                         buf[strlen(buf)-1] =
 474                                 mode != SESSION_ID_AUDIT ? (char) mode : 0;
 475
 476                         if ((r = pam_misc_setenv(handle, "XDG_SESSION_ID", buf, 0)) != PAM_SUCCESS) {
 477                                 pam_syslog(handle, LOG_ERR, "Failed to set session id.");
 478                                 goto finish;
 479                         }
 480
 481                         if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
 482                                 pam_syslog(handle, LOG_ERR, "Failed to get session id.");
 483                                 r = PAM_SESSION_ERR;
 484                                 goto finish;
 485                         }
 486                 }
 487
 488                 r = asprintf(&buf, "%s/%s/%s", cgroup_user_tree, username, id);
 489         } else
 490                 r = asprintf(&buf, "%s/%s/master", cgroup_user_tree, username);
 491
 492         if (r < 0) {
 493                 r = PAM_BUF_ERR;
 494                 goto finish;
 495         }
 496
 497         pam_syslog(handle, LOG_INFO, "Moving new user session for %s into control group %s.", username, buf);
 498
 499         if ((r = create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, buf, pw, true, true)) != PAM_SUCCESS)
 500                 goto finish;
 501
 502         /* The additional controllers don't really matter, so we
 503          * ignore the return value */
 504         STRV_FOREACH(c, controllers)
 505                 create_user_group(handle, *c, buf, pw, true, false);
 506
 507         STRV_FOREACH(c, reset_controllers)
 508                 reset_group(handle, *c);
 509
 510         r = PAM_SUCCESS;
 511
 512 finish:
 513         free(buf);
 514
 515         if (lock_fd >= 0)
 516                 close_nointr_nofail(lock_fd);
 517
 518         strv_free(controllers);
 519         strv_free(reset_controllers);
 520
 521         free(cgroup_user_tree);
 522
 523         return r;
 524 }
 525
 526 static int session_remains(pam_handle_t *handle, const char *user_path) {
 527         int r;
 528         bool remains = false;
 529         DIR *d;
 530         char *subgroup;
 531
 532         if ((r = cg_enumerate_subgroups(SYSTEMD_CGROUP_CONTROLLER, user_path, &d)) < 0)
 533                 return r;
 534
 535         while ((r = cg_read_subgroup(d, &subgroup)) > 0) {
 536
 537                 remains = !streq(subgroup, "master");
 538                 free(subgroup);
 539
 540                 if (remains)
 541                         break;
 542         }
 543
 544         closedir(d);
 545
 546         if (r < 0)
 547                 return r;
 548
 549         return !!remains;
 550 }
 551
 552 static bool check_user_lists(
 553                 pam_handle_t *handle,
 554                 uid_t uid,
 555                 char **kill_only_users,
 556                 char **kill_exclude_users) {
 557
 558         const char *name = NULL;
 559         char **l;
 560
 561         assert(handle);
 562
 563         if (uid == 0)
 564                 name = "root"; /* Avoid obvious NSS requests, to suppress network traffic */
 565         else {
 566                 struct passwd *pw;
 567
 568                 if ((pw = pam_modutil_getpwuid(handle, uid)))
 569                         name = pw->pw_name;
 570         }
 571
 572         STRV_FOREACH(l, kill_exclude_users) {
 573                 uint32_t id;
 574
 575                 if (safe_atou32(*l, &id) >= 0)
 576                         if ((uid_t) id == uid)
 577                                 return false;
 578
 579                 if (name && streq(name, *l))
 580                         return false;
 581         }
 582
 583         if (strv_isempty(kill_only_users))
 584                 return true;
 585
 586         STRV_FOREACH(l, kill_only_users) {
 587                 uint32_t id;
 588
 589                 if (safe_atou32(*l, &id) >= 0)
 590                         if ((uid_t) id == uid)
 591                                 return true;
 592
 593                 if (name && streq(name, *l))
 594                         return true;
 595         }
 596
 597         return false;
 598 }
 599
 600 _public_ PAM_EXTERN int pam_sm_close_session(
 601                 pam_handle_t *handle,
 602                 int flags,
 603                 int argc, const char **argv) {
 604
 605         const char *username = NULL;
 606         bool kill_session = false;
 607         bool kill_user = false;
 608         int lock_fd = -1, r;
 609         char *session_path = NULL, *nosession_path = NULL, *user_path = NULL;
 610         const char *id;
 611         struct passwd *pw;
 612         const void *created = NULL;
 613         char **controllers = NULL, **c, **kill_only_users = NULL, **kill_exclude_users = NULL;
 614         char *cgroup_user_tree = NULL;
 615
 616         assert(handle);
 617
 618         /* Make this a NOP on non-systemd systems */
 619         if (sd_booted() <= 0)
 620                 return PAM_SUCCESS;
 621
 622         if (parse_argv(handle,
 623                        argc, argv,
 624                        NULL, &kill_session, &kill_user,
 625                        &controllers, NULL,
 626                        &kill_only_users, &kill_exclude_users) < 0)
 627                 return PAM_SESSION_ERR;
 628
 629         if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
 630                 goto finish;
 631
 632         if ((r = cg_get_user_path(&cgroup_user_tree)) < 0) {
 633                 pam_syslog(handle, LOG_ERR, "Failed to determine user cgroup tree: %s", strerror(-r));
 634                 r = PAM_SYSTEM_ERR;
 635                 goto finish;
 636         }
 637
 638         if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
 639                 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
 640                 r = PAM_SYSTEM_ERR;
 641                 goto finish;
 642         }
 643
 644         /* We are probably still in some session/user dir. Move ourselves out of the way as first step */
 645         if ((r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, cgroup_user_tree, 0)) < 0)
 646                 pam_syslog(handle, LOG_ERR, "Failed to move us away: %s", strerror(-r));
 647
 648         STRV_FOREACH(c, controllers)
 649                 if ((r = cg_attach(*c, cgroup_user_tree, 0)) < 0)
 650                         pam_syslog(handle, LOG_ERR, "Failed to move us away in %s hierarchy: %s", *c, strerror(-r));
 651
 652         if (asprintf(&user_path, "%s/%s", cgroup_user_tree, username) < 0) {
 653                 r = PAM_BUF_ERR;
 654                 goto finish;
 655         }
 656
 657         pam_get_data(handle, "systemd.created", &created);
 658
 659         if ((id = pam_getenv(handle, "XDG_SESSION_ID")) && created) {
 660
 661                 if (asprintf(&session_path, "%s/%s/%s", cgroup_user_tree, username, id) < 0 ||
 662                     asprintf(&nosession_path, "%s/%s/master", cgroup_user_tree, username) < 0) {
 663                         r = PAM_BUF_ERR;
 664                         goto finish;
 665                 }
 666
 667                 if (kill_session && check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users))  {
 668                         pam_syslog(handle, LOG_INFO, "Killing remaining processes of user session %s of %s.", id, username);
 669
 670                         /* Kill processes in session cgroup, and delete it */
 671                         if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, session_path, true)) < 0)
 672                                 pam_syslog(handle, LOG_ERR, "Failed to kill session cgroup: %s", strerror(-r));
 673                 } else {
 674                         pam_syslog(handle, LOG_INFO, "Moving remaining processes of user session %s of %s into control group %s.", id, username, nosession_path);
 675
 676                         /* Migrate processes from session to user
 677                          * cgroup. First, try to create the user group
 678                          * in case it doesn't exist yet. Also, delete
 679                          * the session group. */
 680                         create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, nosession_path, pw, false, false);
 681
 682                         if ((r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, session_path, nosession_path, false, true)) < 0)
 683                                 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup: %s", strerror(-r));
 684                 }
 685
 686                 STRV_FOREACH(c, controllers) {
 687                         create_user_group(handle, *c, nosession_path, pw, false, false);
 688
 689                         if ((r = cg_migrate_recursive(*c, session_path, nosession_path, false, true)) < 0)
 690                                 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup in hierarchy %s: %s", *c, strerror(-r));
 691                 }
 692         }
 693
 694         /* GC user tree */
 695         cg_trim(SYSTEMD_CGROUP_CONTROLLER, user_path, false);
 696
 697         if ((r = session_remains(handle, user_path)) < 0)
 698                 pam_syslog(handle, LOG_ERR, "Failed to determine whether a session remains: %s", strerror(-r));
 699
 700         /* Kill user processes not attached to any session */
 701         if (kill_user && r == 0 && check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users)) {
 702
 703                 /* Kill user cgroup */
 704                 if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
 705                         pam_syslog(handle, LOG_ERR, "Failed to kill user cgroup: %s", strerror(-r));
 706         } else {
 707
 708                 if ((r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
 709                         pam_syslog(handle, LOG_ERR, "Failed to check user cgroup: %s", strerror(-r));
 710
 711                 /* Remove user cgroup */
 712                 if (r > 0) {
 713                         if ((r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, user_path)) < 0)
 714                                 pam_syslog(handle, LOG_ERR, "Failed to delete user cgroup: %s", strerror(-r));
 715
 716                 /* If we managed to find somebody, don't cleanup the cgroup. */
 717                 } else if (r == 0)
 718                         r = -EBUSY;
 719         }
 720
 721         STRV_FOREACH(c, controllers)
 722                 cg_trim(*c, user_path, true);
 723
 724         if (r >= 0) {
 725                 const char *runtime_dir;
 726
 727                 if ((runtime_dir = pam_getenv(handle, "XDG_RUNTIME_DIR")))
 728                         if ((r = rm_rf(runtime_dir, false, true)) < 0)
 729                                 pam_syslog(handle, LOG_ERR, "Failed to remove runtime directory: %s", strerror(-r));
 730         }
 731
 732         /* pam_syslog(handle, LOG_DEBUG, "pam-systemd done"); */
 733
 734         r = PAM_SUCCESS;
 735
 736 finish:
 737         if (lock_fd >= 0)
 738                 close_nointr_nofail(lock_fd);
 739
 740         free(session_path);
 741         free(nosession_path);
 742         free(user_path);
 743
 744         strv_free(controllers);
 745         strv_free(kill_exclude_users);
 746         strv_free(kill_only_users);
 747
 748         free(cgroup_user_tree);
 749
 750         return r;
 751 }