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 #include <sys/capability.h>
  28
  29 #include <security/pam_modules.h>
  30 #include <security/_pam_macros.h>
  31 #include <security/pam_modutil.h>
  32 #include <security/pam_ext.h>
  33 #include <security/pam_misc.h>
  34
  35 #include "util.h"
  36 #include "cgroup-util.h"
  37 #include "macro.h"
  38 #include "sd-daemon.h"
  39 #include "strv.h"
  40
  41 static int parse_argv(pam_handle_t *handle,
  42                       int argc, const char **argv,
  43                       bool *create_session,
  44                       bool *kill_session,
  45                       bool *kill_user,
  46                       char ***controllers,
  47                       char ***reset_controllers,
  48                       char ***kill_only_users,
  49                       char ***kill_exclude_users) {
  50
  51         unsigned i;
  52         bool reset_controller_set = false;
  53         bool kill_exclude_users_set = false;
  54
  55         assert(argc >= 0);
  56         assert(argc == 0 || argv);
  57
  58         for (i = 0; i < (unsigned) argc; i++) {
  59                 int k;
  60
  61                 if (startswith(argv[i], "create-session=")) {
  62                         if ((k = parse_boolean(argv[i] + 15)) < 0) {
  63                                 pam_syslog(handle, LOG_ERR, "Failed to parse create-session= argument.");
  64                                 return k;
  65                         }
  66
  67                         if (create_session)
  68                                 *create_session = k;
  69
  70                 } else if (startswith(argv[i], "kill-session=")) {
  71                         if ((k = parse_boolean(argv[i] + 13)) < 0) {
  72                                 pam_syslog(handle, LOG_ERR, "Failed to parse kill-session= argument.");
  73                                 return k;
  74                         }
  75
  76                         if (kill_session)
  77                                 *kill_session = k;
  78
  79                 } else if (startswith(argv[i], "kill-user=")) {
  80                         if ((k = parse_boolean(argv[i] + 10)) < 0) {
  81                                 pam_syslog(handle, LOG_ERR, "Failed to parse kill-user= argument.");
  82                                 return k;
  83                         }
  84
  85                         if (kill_user)
  86                                 *kill_user = k;
  87
  88                 } else if (startswith(argv[i], "controllers=")) {
  89
  90                         if (controllers) {
  91                                 char **l;
  92
  93                                 if (!(l = strv_split(argv[i] + 12, ","))) {
  94                                         pam_syslog(handle, LOG_ERR, "Out of memory.");
  95                                         return -ENOMEM;
  96                                 }
  97
  98                                 strv_free(*controllers);
  99                                 *controllers = l;
 100                         }
 101
 102                 } else if (startswith(argv[i], "reset-controllers=")) {
 103
 104                         if (reset_controllers) {
 105                                 char **l;
 106
 107                                 if (!(l = strv_split(argv[i] + 18, ","))) {
 108                                         pam_syslog(handle, LOG_ERR, "Out of memory.");
 109                                         return -ENOMEM;
 110                                 }
 111
 112                                 strv_free(*reset_controllers);
 113                                 *reset_controllers = l;
 114                         }
 115
 116                         reset_controller_set = true;
 117
 118                 } else if (startswith(argv[i], "kill-only-users=")) {
 119
 120                         if (kill_only_users) {
 121                                 char **l;
 122
 123                                 if (!(l = strv_split(argv[i] + 16, ","))) {
 124                                         pam_syslog(handle, LOG_ERR, "Out of memory.");
 125                                         return -ENOMEM;
 126                                 }
 127
 128                                 strv_free(*kill_only_users);
 129                                 *kill_only_users = l;
 130                         }
 131
 132                 } else if (startswith(argv[i], "kill-exclude-users=")) {
 133
 134                         if (kill_exclude_users) {
 135                                 char **l;
 136
 137                                 if (!(l = strv_split(argv[i] + 19, ","))) {
 138                                         pam_syslog(handle, LOG_ERR, "Out of memory.");
 139                                         return -ENOMEM;
 140                                 }
 141
 142                                 strv_free(*kill_exclude_users);
 143                                 *kill_exclude_users = l;
 144                         }
 145
 146                         kill_exclude_users_set = true;
 147
 148                 } else {
 149                         pam_syslog(handle, LOG_ERR, "Unknown parameter '%s'.", argv[i]);
 150                         return -EINVAL;
 151                 }
 152         }
 153
 154         if (!reset_controller_set && reset_controllers) {
 155                 char **l;
 156
 157                 if (!(l = strv_new("cpu", NULL))) {
 158                         pam_syslog(handle, LOG_ERR, "Out of memory");
 159                         return -ENOMEM;
 160                 }
 161
 162                 *reset_controllers = l;
 163         }
 164
 165         if (controllers)
 166                 strv_remove(*controllers, "name=systemd");
 167
 168         if (reset_controllers)
 169                 strv_remove(*reset_controllers, "name=systemd");
 170
 171         if (kill_session && *kill_session && kill_user)
 172                 *kill_user = true;
 173
 174         if (!kill_exclude_users_set && kill_exclude_users) {
 175                 char **l;
 176
 177                 if (!(l = strv_new("root", NULL))) {
 178                         pam_syslog(handle, LOG_ERR, "Out of memory");
 179                         return -ENOMEM;
 180                 }
 181
 182                 *kill_exclude_users = l;
 183         }
 184
 185         return 0;
 186 }
 187
 188 static int open_file_and_lock(const char *fn) {
 189         int fd;
 190
 191         assert(fn);
 192
 193         if ((fd = open(fn, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_CREAT, 0600)) < 0)
 194                 return -errno;
 195
 196         /* The BSD socket semantics are a lot nicer than those of
 197          * POSIX locks. Which is why we use flock() here. BSD locking
 198          * does not work across NFS which however is not needed here
 199          * as the filesystems in question should be local, and only
 200          * locally accessible, and most likely even tmpfs. */
 201
 202         if (flock(fd, LOCK_EX) < 0) {
 203                 close_nointr_nofail(fd);
 204                 return -errno;
 205         }
 206
 207         return fd;
 208 }
 209
 210 enum {
 211         SESSION_ID_AUDIT = 'a',
 212         SESSION_ID_COUNTER = 'c',
 213         SESSION_ID_RANDOM = 'r'
 214 };
 215
 216 static uint64_t get_session_id(int *mode) {
 217         char *s;
 218         int fd;
 219
 220         assert(mode);
 221
 222         /* First attempt: let's use the session ID of the audit
 223          * system, if it is available. */
 224         if (read_one_line_file("/proc/self/sessionid", &s) >= 0) {
 225                 uint32_t u;
 226                 int r;
 227
 228                 r = safe_atou32(s, &u);
 229                 free(s);
 230
 231                 if (r >= 0 && u != (uint32_t) -1 && u > 0) {
 232                         *mode = SESSION_ID_AUDIT;
 233                         return (uint64_t) u;
 234                 }
 235         }
 236
 237         /* Second attempt, use our own counter. */
 238         if ((fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-session")) >= 0) {
 239                 uint64_t counter;
 240                 ssize_t r;
 241
 242                 /* We do a bit of endianess swapping here, just to be
 243                  * sure. /run should be machine specific anyway, and
 244                  * even mounted from tmpfs, so this byteswapping
 245                  * should really not be necessary. But then again, you
 246                  * never know, so let's avoid any risk. */
 247
 248                 if (loop_read(fd, &counter, sizeof(counter), false) != sizeof(counter))
 249                         counter = 1;
 250                 else
 251                         counter = le64toh(counter) + 1;
 252
 253                 if (lseek(fd, 0, SEEK_SET) == 0) {
 254                         uint64_t swapped = htole64(counter);
 255
 256                         r = loop_write(fd, &swapped, sizeof(swapped), false);
 257
 258                         if (r != sizeof(swapped))
 259                                 r = -EIO;
 260                 } else
 261                         r = -errno;
 262
 263                 close_nointr_nofail(fd);
 264
 265                 if (r >= 0) {
 266                         *mode = SESSION_ID_COUNTER;
 267                         return counter;
 268                 }
 269         }
 270
 271         *mode = SESSION_ID_RANDOM;
 272
 273         /* Last attempt, pick a random value */
 274         return (uint64_t) random_ull();
 275 }
 276
 277 static int get_user_data(
 278                 pam_handle_t *handle,
 279                 const char **ret_username,
 280                 struct passwd **ret_pw) {
 281
 282         const char *username = NULL;
 283         struct passwd *pw = NULL;
 284         int r;
 285         bool have_loginuid = false;
 286         char *s;
 287
 288         assert(handle);
 289         assert(ret_username);
 290         assert(ret_pw);
 291
 292         if (have_effective_cap(CAP_AUDIT_CONTROL)) {
 293                 /* Only use audit login uid if we are executed with
 294                  * sufficient capabilities so that pam_loginuid could
 295                  * do its job. If we are lacking the CAP_AUDIT_CONTROL
 296                  * capabality we most likely are being run in a
 297                  * container and /proc/self/loginuid is useless since
 298                  * it probably contains a uid of the host system. */
 299
 300                 if (read_one_line_file("/proc/self/loginuid", &s) >= 0) {
 301                         uint32_t u;
 302
 303                         r = safe_atou32(s, &u);
 304                         free(s);
 305
 306                         if (r >= 0 && u != (uint32_t) -1 && u > 0) {
 307                                 have_loginuid = true;
 308                                 pw = pam_modutil_getpwuid(handle, u);
 309                         }
 310                 }
 311         }
 312
 313         if (!have_loginuid) {
 314                 if ((r = pam_get_user(handle, &username, NULL)) != PAM_SUCCESS) {
 315                         pam_syslog(handle, LOG_ERR, "Failed to get user name.");
 316                         return r;
 317                 }
 318
 319                 if (!username || !*username) {
 320                         pam_syslog(handle, LOG_ERR, "User name not valid.");
 321                         return PAM_AUTH_ERR;
 322                 }
 323
 324                 pw = pam_modutil_getpwnam(handle, username);
 325         }
 326
 327         if (!pw) {
 328                 pam_syslog(handle, LOG_ERR, "Failed to get user data.");
 329                 return PAM_USER_UNKNOWN;
 330         }
 331
 332         *ret_pw = pw;
 333         *ret_username = username ? username : pw->pw_name;
 334
 335         return PAM_SUCCESS;
 336 }
 337
 338 static int create_user_group(
 339                 pam_handle_t *handle,
 340                 const char *controller,
 341                 const char *group,
 342                 struct passwd *pw,
 343                 bool attach,
 344                 bool remember) {
 345
 346         int r;
 347
 348         assert(handle);
 349         assert(group);
 350
 351         if (attach)
 352                 r = cg_create_and_attach(controller, group, 0);
 353         else
 354                 r = cg_create(controller, group);
 355
 356         if (r < 0) {
 357                 pam_syslog(handle, LOG_ERR, "Failed to create cgroup: %s", strerror(-r));
 358                 return PAM_SESSION_ERR;
 359         }
 360
 361         if (r > 0 && remember) {
 362                 /* Remember that it was us who created this group, and
 363                  * that hence we need to remove it too. This is a
 364                  * protection against removing the cgroup when run
 365                  * recursively. */
 366                 if ((r = pam_set_data(handle, "systemd.created", INT_TO_PTR(1), NULL)) != PAM_SUCCESS) {
 367                         pam_syslog(handle, LOG_ERR, "Failed to install created variable.");
 368                         return r;
 369                 }
 370         }
 371
 372         if ((r = cg_set_task_access(controller, group, 0644, pw->pw_uid, pw->pw_gid)) < 0 ||
 373             (r = cg_set_group_access(controller, group, 0755, pw->pw_uid, pw->pw_gid)) < 0) {
 374                 pam_syslog(handle, LOG_ERR, "Failed to change access modes: %s", strerror(-r));
 375                 return PAM_SESSION_ERR;
 376         }
 377
 378         return PAM_SUCCESS;
 379 }
 380
 381 static int reset_group(
 382                 pam_handle_t *handle,
 383                 const char *controller) {
 384
 385         int r;
 386
 387         assert(handle);
 388
 389         if ((r = cg_attach(controller, "/", 0)) < 0) {
 390                 pam_syslog(handle, LOG_ERR, "Failed to reset cgroup for controller %s: %s", controller, strerror(-r));
 391                 return PAM_SESSION_ERR;
 392         }
 393
 394         return PAM_SUCCESS;
 395 }
 396
 397 _public_ PAM_EXTERN int pam_sm_open_session(
 398                 pam_handle_t *handle,
 399                 int flags,
 400                 int argc, const char **argv) {
 401
 402         const char *username = NULL;
 403         struct passwd *pw;
 404         int r;
 405         char *buf = NULL;
 406         int lock_fd = -1;
 407         bool create_session = true;
 408         char **controllers = NULL, **reset_controllers = NULL, **c;
 409         char *cgroup_user_tree = NULL;
 410
 411         assert(handle);
 412
 413         /* pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing"); */
 414
 415         /* Make this a NOP on non-systemd systems */
 416         if (sd_booted() <= 0)
 417                 return PAM_SUCCESS;
 418
 419         if (parse_argv(handle,
 420                        argc, argv,
 421                        &create_session, NULL, NULL,
 422                        &controllers, &reset_controllers,
 423                        NULL, NULL) < 0)
 424                 return PAM_SESSION_ERR;
 425
 426         if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
 427                 goto finish;
 428
 429         if ((r = cg_get_user_path(&cgroup_user_tree)) < 0) {
 430                 pam_syslog(handle, LOG_ERR, "Failed to determine user cgroup tree: %s", strerror(-r));
 431                 r = PAM_SYSTEM_ERR;
 432                 goto finish;
 433         }
 434
 435         if (safe_mkdir(RUNTIME_DIR "/user", 0755, 0, 0) < 0) {
 436                 pam_syslog(handle, LOG_ERR, "Failed to create runtime directory: %m");
 437                 r = PAM_SYSTEM_ERR;
 438                 goto finish;
 439         }
 440
 441         if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
 442                 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
 443                 r = PAM_SYSTEM_ERR;
 444                 goto finish;
 445         }
 446
 447         /* Create /run/user/$USER */
 448         free(buf);
 449         if (asprintf(&buf, RUNTIME_DIR "/user/%s", username) < 0) {
 450                 r = PAM_BUF_ERR;
 451                 goto finish;
 452         }
 453
 454         if (safe_mkdir(buf, 0700, pw->pw_uid, pw->pw_gid) < 0) {
 455                 pam_syslog(handle, LOG_WARNING, "Failed to create runtime directory: %m");
 456                 r = PAM_SYSTEM_ERR;
 457                 goto finish;
 458         } else if ((r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", buf, 0)) != PAM_SUCCESS) {
 459                 pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
 460                 goto finish;
 461         }
 462
 463         free(buf);
 464         buf = NULL;
 465
 466         if (create_session) {
 467                 const char *id;
 468
 469                 /* Reuse or create XDG session ID */
 470                 if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
 471                         int mode;
 472
 473                         if (asprintf(&buf, "%llux", (unsigned long long) get_session_id(&mode)) < 0) {
 474                                 r = PAM_BUF_ERR;
 475                                 goto finish;
 476                         }
 477
 478                         /* To avoid id clashes we add the session id
 479                          * source to our session ids. Note that the
 480                          * session id source might change during
 481                          * runtime, because a filesystem became
 482                          * writable or the system reconfigured. */
 483                         buf[strlen(buf)-1] =
 484                                 mode != SESSION_ID_AUDIT ? (char) mode : 0;
 485
 486                         if ((r = pam_misc_setenv(handle, "XDG_SESSION_ID", buf, 0)) != PAM_SUCCESS) {
 487                                 pam_syslog(handle, LOG_ERR, "Failed to set session id.");
 488                                 goto finish;
 489                         }
 490
 491                         if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
 492                                 pam_syslog(handle, LOG_ERR, "Failed to get session id.");
 493                                 r = PAM_SESSION_ERR;
 494                                 goto finish;
 495                         }
 496                 }
 497
 498                 r = asprintf(&buf, "%s/%s/%s", cgroup_user_tree, username, id);
 499         } else
 500                 r = asprintf(&buf, "%s/%s/master", cgroup_user_tree, username);
 501
 502         if (r < 0) {
 503                 r = PAM_BUF_ERR;
 504                 goto finish;
 505         }
 506
 507         pam_syslog(handle, LOG_INFO, "Moving new user session for %s into control group %s.", username, buf);
 508
 509         if ((r = create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, buf, pw, true, true)) != PAM_SUCCESS)
 510                 goto finish;
 511
 512         /* The additional controllers don't really matter, so we
 513          * ignore the return value */
 514         STRV_FOREACH(c, controllers)
 515                 create_user_group(handle, *c, buf, pw, true, false);
 516
 517         STRV_FOREACH(c, reset_controllers)
 518                 reset_group(handle, *c);
 519
 520         r = PAM_SUCCESS;
 521
 522 finish:
 523         free(buf);
 524
 525         if (lock_fd >= 0)
 526                 close_nointr_nofail(lock_fd);
 527
 528         strv_free(controllers);
 529         strv_free(reset_controllers);
 530
 531         free(cgroup_user_tree);
 532
 533         return r;
 534 }
 535
 536 static int session_remains(pam_handle_t *handle, const char *user_path) {
 537         int r;
 538         bool remains = false;
 539         DIR *d;
 540         char *subgroup;
 541
 542         if ((r = cg_enumerate_subgroups(SYSTEMD_CGROUP_CONTROLLER, user_path, &d)) < 0)
 543                 return r;
 544
 545         while ((r = cg_read_subgroup(d, &subgroup)) > 0) {
 546
 547                 remains = !streq(subgroup, "master");
 548                 free(subgroup);
 549
 550                 if (remains)
 551                         break;
 552         }
 553
 554         closedir(d);
 555
 556         if (r < 0)
 557                 return r;
 558
 559         return !!remains;
 560 }
 561
 562 static bool check_user_lists(
 563                 pam_handle_t *handle,
 564                 uid_t uid,
 565                 char **kill_only_users,
 566                 char **kill_exclude_users) {
 567
 568         const char *name = NULL;
 569         char **l;
 570
 571         assert(handle);
 572
 573         if (uid == 0)
 574                 name = "root"; /* Avoid obvious NSS requests, to suppress network traffic */
 575         else {
 576                 struct passwd *pw;
 577
 578                 if ((pw = pam_modutil_getpwuid(handle, uid)))
 579                         name = pw->pw_name;
 580         }
 581
 582         STRV_FOREACH(l, kill_exclude_users) {
 583                 uint32_t id;
 584
 585                 if (safe_atou32(*l, &id) >= 0)
 586                         if ((uid_t) id == uid)
 587                                 return false;
 588
 589                 if (name && streq(name, *l))
 590                         return false;
 591         }
 592
 593         if (strv_isempty(kill_only_users))
 594                 return true;
 595
 596         STRV_FOREACH(l, kill_only_users) {
 597                 uint32_t id;
 598
 599                 if (safe_atou32(*l, &id) >= 0)
 600                         if ((uid_t) id == uid)
 601                                 return true;
 602
 603                 if (name && streq(name, *l))
 604                         return true;
 605         }
 606
 607         return false;
 608 }
 609
 610 _public_ PAM_EXTERN int pam_sm_close_session(
 611                 pam_handle_t *handle,
 612                 int flags,
 613                 int argc, const char **argv) {
 614
 615         const char *username = NULL;
 616         bool kill_session = false;
 617         bool kill_user = false;
 618         int lock_fd = -1, r;
 619         char *session_path = NULL, *nosession_path = NULL, *user_path = NULL;
 620         const char *id;
 621         struct passwd *pw;
 622         const void *created = NULL;
 623         char **controllers = NULL, **c, **kill_only_users = NULL, **kill_exclude_users = NULL;
 624         char *cgroup_user_tree = NULL;
 625
 626         assert(handle);
 627
 628         /* Make this a NOP on non-systemd systems */
 629         if (sd_booted() <= 0)
 630                 return PAM_SUCCESS;
 631
 632         if (parse_argv(handle,
 633                        argc, argv,
 634                        NULL, &kill_session, &kill_user,
 635                        &controllers, NULL,
 636                        &kill_only_users, &kill_exclude_users) < 0)
 637                 return PAM_SESSION_ERR;
 638
 639         if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
 640                 goto finish;
 641
 642         if ((r = cg_get_user_path(&cgroup_user_tree)) < 0) {
 643                 pam_syslog(handle, LOG_ERR, "Failed to determine user cgroup tree: %s", strerror(-r));
 644                 r = PAM_SYSTEM_ERR;
 645                 goto finish;
 646         }
 647
 648         if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
 649                 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
 650                 r = PAM_SYSTEM_ERR;
 651                 goto finish;
 652         }
 653
 654         /* We are probably still in some session/user dir. Move ourselves out of the way as first step */
 655         if ((r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, cgroup_user_tree, 0)) < 0)
 656                 pam_syslog(handle, LOG_ERR, "Failed to move us away: %s", strerror(-r));
 657
 658         STRV_FOREACH(c, controllers)
 659                 if ((r = cg_attach(*c, cgroup_user_tree, 0)) < 0)
 660                         pam_syslog(handle, LOG_ERR, "Failed to move us away in %s hierarchy: %s", *c, strerror(-r));
 661
 662         if (asprintf(&user_path, "%s/%s", cgroup_user_tree, username) < 0) {
 663                 r = PAM_BUF_ERR;
 664                 goto finish;
 665         }
 666
 667         pam_get_data(handle, "systemd.created", &created);
 668
 669         if ((id = pam_getenv(handle, "XDG_SESSION_ID")) && created) {
 670
 671                 if (asprintf(&session_path, "%s/%s/%s", cgroup_user_tree, username, id) < 0 ||
 672                     asprintf(&nosession_path, "%s/%s/master", cgroup_user_tree, username) < 0) {
 673                         r = PAM_BUF_ERR;
 674                         goto finish;
 675                 }
 676
 677                 if (kill_session && check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users))  {
 678                         pam_syslog(handle, LOG_INFO, "Killing remaining processes of user session %s of %s.", id, username);
 679
 680                         /* Kill processes in session cgroup, and delete it */
 681                         if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, session_path, true)) < 0)
 682                                 pam_syslog(handle, LOG_ERR, "Failed to kill session cgroup: %s", strerror(-r));
 683                 } else {
 684                         pam_syslog(handle, LOG_INFO, "Moving remaining processes of user session %s of %s into control group %s.", id, username, nosession_path);
 685
 686                         /* Migrate processes from session to user
 687                          * cgroup. First, try to create the user group
 688                          * in case it doesn't exist yet. Also, delete
 689                          * the session group. */
 690                         create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, nosession_path, pw, false, false);
 691
 692                         if ((r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, session_path, nosession_path, false, true)) < 0)
 693                                 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup: %s", strerror(-r));
 694                 }
 695
 696                 STRV_FOREACH(c, controllers) {
 697                         create_user_group(handle, *c, nosession_path, pw, false, false);
 698
 699                         if ((r = cg_migrate_recursive(*c, session_path, nosession_path, false, true)) < 0)
 700                                 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup in hierarchy %s: %s", *c, strerror(-r));
 701                 }
 702         }
 703
 704         /* GC user tree */
 705         cg_trim(SYSTEMD_CGROUP_CONTROLLER, user_path, false);
 706
 707         if ((r = session_remains(handle, user_path)) < 0)
 708                 pam_syslog(handle, LOG_ERR, "Failed to determine whether a session remains: %s", strerror(-r));
 709
 710         /* Kill user processes not attached to any session */
 711         if (kill_user && r == 0 && check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users)) {
 712
 713                 /* Kill user cgroup */
 714                 if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
 715                         pam_syslog(handle, LOG_ERR, "Failed to kill user cgroup: %s", strerror(-r));
 716         } else {
 717
 718                 if ((r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
 719                         pam_syslog(handle, LOG_ERR, "Failed to check user cgroup: %s", strerror(-r));
 720
 721                 /* Remove user cgroup */
 722                 if (r > 0) {
 723                         if ((r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, user_path)) < 0)
 724                                 pam_syslog(handle, LOG_ERR, "Failed to delete user cgroup: %s", strerror(-r));
 725
 726                 /* If we managed to find somebody, don't cleanup the cgroup. */
 727                 } else if (r == 0)
 728                         r = -EBUSY;
 729         }
 730
 731         STRV_FOREACH(c, controllers)
 732                 cg_trim(*c, user_path, true);
 733
 734         if (r >= 0) {
 735                 const char *runtime_dir;
 736
 737                 if ((runtime_dir = pam_getenv(handle, "XDG_RUNTIME_DIR")))
 738                         if ((r = rm_rf(runtime_dir, false, true)) < 0)
 739                                 pam_syslog(handle, LOG_ERR, "Failed to remove runtime directory: %s", strerror(-r));
 740         }
 741
 742         /* pam_syslog(handle, LOG_DEBUG, "pam-systemd done"); */
 743
 744         r = PAM_SUCCESS;
 745
 746 finish:
 747         if (lock_fd >= 0)
 748                 close_nointr_nofail(lock_fd);
 749
 750         free(session_path);
 751         free(nosession_path);
 752         free(user_path);
 753
 754         strv_free(controllers);
 755         strv_free(kill_exclude_users);
 756         strv_free(kill_only_users);
 757
 758         free(cgroup_user_tree);
 759
 760         return r;
 761 }