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 (have_effective_cap(CAP_AUDIT_CONTROL) > 0)
 225                 if (read_one_line_file("/proc/self/sessionid", &s) >= 0) {
 226                         uint32_t u;
 227                         int r;
 228
 229                         r = safe_atou32(s, &u);
 230                         free(s);
 231
 232                         if (r >= 0 && u != (uint32_t) -1 && u > 0) {
 233                                 *mode = SESSION_ID_AUDIT;
 234                                 return (uint64_t) u;
 235                         }
 236                 }
 237
 238         /* Second attempt, use our own counter. */
 239         if ((fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-session")) >= 0) {
 240                 uint64_t counter;
 241                 ssize_t r;
 242
 243                 /* We do a bit of endianess swapping here, just to be
 244                  * sure. /run should be machine specific anyway, and
 245                  * even mounted from tmpfs, so this byteswapping
 246                  * should really not be necessary. But then again, you
 247                  * never know, so let's avoid any risk. */
 248
 249                 if (loop_read(fd, &counter, sizeof(counter), false) != sizeof(counter))
 250                         counter = 1;
 251                 else
 252                         counter = le64toh(counter) + 1;
 253
 254                 if (lseek(fd, 0, SEEK_SET) == 0) {
 255                         uint64_t swapped = htole64(counter);
 256
 257                         r = loop_write(fd, &swapped, sizeof(swapped), false);
 258
 259                         if (r != sizeof(swapped))
 260                                 r = -EIO;
 261                 } else
 262                         r = -errno;
 263
 264                 close_nointr_nofail(fd);
 265
 266                 if (r >= 0) {
 267                         *mode = SESSION_ID_COUNTER;
 268                         return counter;
 269                 }
 270         }
 271
 272         *mode = SESSION_ID_RANDOM;
 273
 274         /* Last attempt, pick a random value */
 275         return (uint64_t) random_ull();
 276 }
 277
 278 static int get_user_data(
 279                 pam_handle_t *handle,
 280                 const char **ret_username,
 281                 struct passwd **ret_pw) {
 282
 283         const char *username = NULL;
 284         struct passwd *pw = NULL;
 285         int r;
 286         bool have_loginuid = false;
 287         char *s;
 288
 289         assert(handle);
 290         assert(ret_username);
 291         assert(ret_pw);
 292
 293         if (have_effective_cap(CAP_AUDIT_CONTROL) > 0) {
 294                 /* Only use audit login uid if we are executed with
 295                  * sufficient capabilities so that pam_loginuid could
 296                  * do its job. If we are lacking the CAP_AUDIT_CONTROL
 297                  * capabality we most likely are being run in a
 298                  * container and /proc/self/loginuid is useless since
 299                  * it probably contains a uid of the host system. */
 300
 301                 if (read_one_line_file("/proc/self/loginuid", &s) >= 0) {
 302                         uint32_t u;
 303
 304                         r = safe_atou32(s, &u);
 305                         free(s);
 306
 307                         if (r >= 0 && u != (uint32_t) -1 && u > 0) {
 308                                 have_loginuid = true;
 309                                 pw = pam_modutil_getpwuid(handle, u);
 310                         }
 311                 }
 312         }
 313
 314         if (!have_loginuid) {
 315                 if ((r = pam_get_user(handle, &username, NULL)) != PAM_SUCCESS) {
 316                         pam_syslog(handle, LOG_ERR, "Failed to get user name.");
 317                         return r;
 318                 }
 319
 320                 if (!username || !*username) {
 321                         pam_syslog(handle, LOG_ERR, "User name not valid.");
 322                         return PAM_AUTH_ERR;
 323                 }
 324
 325                 pw = pam_modutil_getpwnam(handle, username);
 326         }
 327
 328         if (!pw) {
 329                 pam_syslog(handle, LOG_ERR, "Failed to get user data.");
 330                 return PAM_USER_UNKNOWN;
 331         }
 332
 333         *ret_pw = pw;
 334         *ret_username = username ? username : pw->pw_name;
 335
 336         return PAM_SUCCESS;
 337 }
 338
 339 static int create_user_group(
 340                 pam_handle_t *handle,
 341                 const char *controller,
 342                 const char *group,
 343                 struct passwd *pw,
 344                 bool attach,
 345                 bool remember) {
 346
 347         int r;
 348
 349         assert(handle);
 350         assert(group);
 351
 352         if (attach)
 353                 r = cg_create_and_attach(controller, group, 0);
 354         else
 355                 r = cg_create(controller, group);
 356
 357         if (r < 0) {
 358                 pam_syslog(handle, LOG_ERR, "Failed to create cgroup: %s", strerror(-r));
 359                 return PAM_SESSION_ERR;
 360         }
 361
 362         if (r > 0 && remember) {
 363                 /* Remember that it was us who created this group, and
 364                  * that hence we need to remove it too. This is a
 365                  * protection against removing the cgroup when run
 366                  * recursively. */
 367                 if ((r = pam_set_data(handle, "systemd.created", INT_TO_PTR(1), NULL)) != PAM_SUCCESS) {
 368                         pam_syslog(handle, LOG_ERR, "Failed to install created variable.");
 369                         return r;
 370                 }
 371         }
 372
 373         if ((r = cg_set_task_access(controller, group, 0644, pw->pw_uid, pw->pw_gid)) < 0 ||
 374             (r = cg_set_group_access(controller, group, 0755, pw->pw_uid, pw->pw_gid)) < 0) {
 375                 pam_syslog(handle, LOG_ERR, "Failed to change access modes: %s", strerror(-r));
 376                 return PAM_SESSION_ERR;
 377         }
 378
 379         return PAM_SUCCESS;
 380 }
 381
 382 static int reset_group(
 383                 pam_handle_t *handle,
 384                 const char *controller) {
 385
 386         int r;
 387
 388         assert(handle);
 389
 390         if ((r = cg_attach(controller, "/", 0)) < 0) {
 391                 pam_syslog(handle, LOG_ERR, "Failed to reset cgroup for controller %s: %s", controller, strerror(-r));
 392                 return PAM_SESSION_ERR;
 393         }
 394
 395         return PAM_SUCCESS;
 396 }
 397
 398 _public_ PAM_EXTERN int pam_sm_open_session(
 399                 pam_handle_t *handle,
 400                 int flags,
 401                 int argc, const char **argv) {
 402
 403         const char *username = NULL;
 404         struct passwd *pw;
 405         int r;
 406         char *buf = NULL;
 407         int lock_fd = -1;
 408         bool create_session = true;
 409         char **controllers = NULL, **reset_controllers = NULL, **c;
 410         char *cgroup_user_tree = NULL;
 411
 412         assert(handle);
 413
 414         /* pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing"); */
 415
 416         /* Make this a NOP on non-systemd systems */
 417         if (sd_booted() <= 0)
 418                 return PAM_SUCCESS;
 419
 420         if (parse_argv(handle,
 421                        argc, argv,
 422                        &create_session, NULL, NULL,
 423                        &controllers, &reset_controllers,
 424                        NULL, NULL) < 0)
 425                 return PAM_SESSION_ERR;
 426
 427         if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
 428                 goto finish;
 429
 430         if ((r = cg_get_user_path(&cgroup_user_tree)) < 0) {
 431                 pam_syslog(handle, LOG_ERR, "Failed to determine user cgroup tree: %s", strerror(-r));
 432                 r = PAM_SYSTEM_ERR;
 433                 goto finish;
 434         }
 435
 436         if (safe_mkdir(RUNTIME_DIR "/user", 0755, 0, 0) < 0) {
 437                 pam_syslog(handle, LOG_ERR, "Failed to create runtime directory: %m");
 438                 r = PAM_SYSTEM_ERR;
 439                 goto finish;
 440         }
 441
 442         if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
 443                 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
 444                 r = PAM_SYSTEM_ERR;
 445                 goto finish;
 446         }
 447
 448         /* Create /run/user/$USER */
 449         free(buf);
 450         if (asprintf(&buf, RUNTIME_DIR "/user/%s", username) < 0) {
 451                 r = PAM_BUF_ERR;
 452                 goto finish;
 453         }
 454
 455         if (safe_mkdir(buf, 0700, pw->pw_uid, pw->pw_gid) < 0) {
 456                 pam_syslog(handle, LOG_WARNING, "Failed to create runtime directory: %m");
 457                 r = PAM_SYSTEM_ERR;
 458                 goto finish;
 459         } else if ((r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", buf, 0)) != PAM_SUCCESS) {
 460                 pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
 461                 goto finish;
 462         }
 463
 464         free(buf);
 465         buf = NULL;
 466
 467         if (create_session) {
 468                 const char *id;
 469
 470                 /* Reuse or create XDG session ID */
 471                 if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
 472                         int mode;
 473
 474                         if (asprintf(&buf, "%llux", (unsigned long long) get_session_id(&mode)) < 0) {
 475                                 r = PAM_BUF_ERR;
 476                                 goto finish;
 477                         }
 478
 479                         /* To avoid id clashes we add the session id
 480                          * source to our session ids. Note that the
 481                          * session id source might change during
 482                          * runtime, because a filesystem became
 483                          * writable or the system reconfigured. */
 484                         buf[strlen(buf)-1] =
 485                                 mode != SESSION_ID_AUDIT ? (char) mode : 0;
 486
 487                         if ((r = pam_misc_setenv(handle, "XDG_SESSION_ID", buf, 0)) != PAM_SUCCESS) {
 488                                 pam_syslog(handle, LOG_ERR, "Failed to set session id.");
 489                                 goto finish;
 490                         }
 491
 492                         if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
 493                                 pam_syslog(handle, LOG_ERR, "Failed to get session id.");
 494                                 r = PAM_SESSION_ERR;
 495                                 goto finish;
 496                         }
 497                 }
 498
 499                 r = asprintf(&buf, "%s/%s/%s", cgroup_user_tree, username, id);
 500         } else
 501                 r = asprintf(&buf, "%s/%s/master", cgroup_user_tree, username);
 502
 503         if (r < 0) {
 504                 r = PAM_BUF_ERR;
 505                 goto finish;
 506         }
 507
 508         pam_syslog(handle, LOG_DEBUG, "Moving new user session for %s into control group %s.", username, buf);
 509
 510         if ((r = create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, buf, pw, true, true)) != PAM_SUCCESS)
 511                 goto finish;
 512
 513         /* The additional controllers don't really matter, so we
 514          * ignore the return value */
 515         STRV_FOREACH(c, controllers)
 516                 create_user_group(handle, *c, buf, pw, true, false);
 517
 518         STRV_FOREACH(c, reset_controllers)
 519                 reset_group(handle, *c);
 520
 521         r = PAM_SUCCESS;
 522
 523 finish:
 524         free(buf);
 525
 526         if (lock_fd >= 0)
 527                 close_nointr_nofail(lock_fd);
 528
 529         strv_free(controllers);
 530         strv_free(reset_controllers);
 531
 532         free(cgroup_user_tree);
 533
 534         return r;
 535 }
 536
 537 static int session_remains(pam_handle_t *handle, const char *user_path) {
 538         int r;
 539         bool remains = false;
 540         DIR *d;
 541         char *subgroup;
 542
 543         if ((r = cg_enumerate_subgroups(SYSTEMD_CGROUP_CONTROLLER, user_path, &d)) < 0)
 544                 return r;
 545
 546         while ((r = cg_read_subgroup(d, &subgroup)) > 0) {
 547
 548                 remains = !streq(subgroup, "master");
 549                 free(subgroup);
 550
 551                 if (remains)
 552                         break;
 553         }
 554
 555         closedir(d);
 556
 557         if (r < 0)
 558                 return r;
 559
 560         return !!remains;
 561 }
 562
 563 static bool check_user_lists(
 564                 pam_handle_t *handle,
 565                 uid_t uid,
 566                 char **kill_only_users,
 567                 char **kill_exclude_users) {
 568
 569         const char *name = NULL;
 570         char **l;
 571
 572         assert(handle);
 573
 574         if (uid == 0)
 575                 name = "root"; /* Avoid obvious NSS requests, to suppress network traffic */
 576         else {
 577                 struct passwd *pw;
 578
 579                 if ((pw = pam_modutil_getpwuid(handle, uid)))
 580                         name = pw->pw_name;
 581         }
 582
 583         STRV_FOREACH(l, kill_exclude_users) {
 584                 uint32_t id;
 585
 586                 if (safe_atou32(*l, &id) >= 0)
 587                         if ((uid_t) id == uid)
 588                                 return false;
 589
 590                 if (name && streq(name, *l))
 591                         return false;
 592         }
 593
 594         if (strv_isempty(kill_only_users))
 595                 return true;
 596
 597         STRV_FOREACH(l, kill_only_users) {
 598                 uint32_t id;
 599
 600                 if (safe_atou32(*l, &id) >= 0)
 601                         if ((uid_t) id == uid)
 602                                 return true;
 603
 604                 if (name && streq(name, *l))
 605                         return true;
 606         }
 607
 608         return false;
 609 }
 610
 611 _public_ PAM_EXTERN int pam_sm_close_session(
 612                 pam_handle_t *handle,
 613                 int flags,
 614                 int argc, const char **argv) {
 615
 616         const char *username = NULL;
 617         bool kill_session = false;
 618         bool kill_user = false;
 619         int lock_fd = -1, r;
 620         char *session_path = NULL, *nosession_path = NULL, *user_path = NULL;
 621         const char *id;
 622         struct passwd *pw;
 623         const void *created = NULL;
 624         char **controllers = NULL, **c, **kill_only_users = NULL, **kill_exclude_users = NULL;
 625         char *cgroup_user_tree = NULL;
 626
 627         assert(handle);
 628
 629         /* Make this a NOP on non-systemd systems */
 630         if (sd_booted() <= 0)
 631                 return PAM_SUCCESS;
 632
 633         if (parse_argv(handle,
 634                        argc, argv,
 635                        NULL, &kill_session, &kill_user,
 636                        &controllers, NULL,
 637                        &kill_only_users, &kill_exclude_users) < 0)
 638                 return PAM_SESSION_ERR;
 639
 640         if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
 641                 goto finish;
 642
 643         if ((r = cg_get_user_path(&cgroup_user_tree)) < 0) {
 644                 pam_syslog(handle, LOG_ERR, "Failed to determine user cgroup tree: %s", strerror(-r));
 645                 r = PAM_SYSTEM_ERR;
 646                 goto finish;
 647         }
 648
 649         if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
 650                 pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
 651                 r = PAM_SYSTEM_ERR;
 652                 goto finish;
 653         }
 654
 655         /* We are probably still in some session/user dir. Move ourselves out of the way as first step */
 656         if ((r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, cgroup_user_tree, 0)) < 0)
 657                 pam_syslog(handle, LOG_ERR, "Failed to move us away: %s", strerror(-r));
 658
 659         STRV_FOREACH(c, controllers)
 660                 if ((r = cg_attach(*c, cgroup_user_tree, 0)) < 0)
 661                         pam_syslog(handle, LOG_ERR, "Failed to move us away in %s hierarchy: %s", *c, strerror(-r));
 662
 663         if (asprintf(&user_path, "%s/%s", cgroup_user_tree, username) < 0) {
 664                 r = PAM_BUF_ERR;
 665                 goto finish;
 666         }
 667
 668         pam_get_data(handle, "systemd.created", &created);
 669
 670         if ((id = pam_getenv(handle, "XDG_SESSION_ID")) && created) {
 671
 672                 if (asprintf(&session_path, "%s/%s/%s", cgroup_user_tree, username, id) < 0 ||
 673                     asprintf(&nosession_path, "%s/%s/master", cgroup_user_tree, username) < 0) {
 674                         r = PAM_BUF_ERR;
 675                         goto finish;
 676                 }
 677
 678                 if (kill_session && check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users))  {
 679                         pam_syslog(handle, LOG_DEBUG, "Killing remaining processes of user session %s of %s.", id, username);
 680
 681                         /* Kill processes in session cgroup, and delete it */
 682                         if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, session_path, true)) < 0)
 683                                 pam_syslog(handle, LOG_ERR, "Failed to kill session cgroup: %s", strerror(-r));
 684                 } else {
 685                         pam_syslog(handle, LOG_DEBUG, "Moving remaining processes of user session %s of %s into control group %s.", id, username, nosession_path);
 686
 687                         /* Migrate processes from session to user
 688                          * cgroup. First, try to create the user group
 689                          * in case it doesn't exist yet. Also, delete
 690                          * the session group. */
 691                         create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, nosession_path, pw, false, false);
 692
 693                         if ((r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, session_path, nosession_path, false, true)) < 0)
 694                                 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup: %s", strerror(-r));
 695                 }
 696
 697                 STRV_FOREACH(c, controllers) {
 698                         create_user_group(handle, *c, nosession_path, pw, false, false);
 699
 700                         if ((r = cg_migrate_recursive(*c, session_path, nosession_path, false, true)) < 0)
 701                                 pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup in hierarchy %s: %s", *c, strerror(-r));
 702                 }
 703         }
 704
 705         /* GC user tree */
 706         cg_trim(SYSTEMD_CGROUP_CONTROLLER, user_path, false);
 707
 708         if ((r = session_remains(handle, user_path)) < 0)
 709                 pam_syslog(handle, LOG_ERR, "Failed to determine whether a session remains: %s", strerror(-r));
 710
 711         /* Kill user processes not attached to any session */
 712         if (kill_user && r == 0 && check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users)) {
 713
 714                 /* Kill user cgroup */
 715                 if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
 716                         pam_syslog(handle, LOG_ERR, "Failed to kill user cgroup: %s", strerror(-r));
 717         } else {
 718
 719                 if ((r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0)
 720                         pam_syslog(handle, LOG_ERR, "Failed to check user cgroup: %s", strerror(-r));
 721
 722                 /* Remove user cgroup */
 723                 if (r > 0) {
 724                         if ((r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, user_path)) < 0)
 725                                 pam_syslog(handle, LOG_ERR, "Failed to delete user cgroup: %s", strerror(-r));
 726
 727                 /* If we managed to find somebody, don't cleanup the cgroup. */
 728                 } else if (r == 0)
 729                         r = -EBUSY;
 730         }
 731
 732         STRV_FOREACH(c, controllers)
 733                 cg_trim(*c, user_path, true);
 734
 735         if (r >= 0) {
 736                 const char *runtime_dir;
 737
 738                 if ((runtime_dir = pam_getenv(handle, "XDG_RUNTIME_DIR")))
 739                         if ((r = rm_rf(runtime_dir, false, true)) < 0)
 740                                 pam_syslog(handle, LOG_ERR, "Failed to remove runtime directory: %s", strerror(-r));
 741         }
 742
 743         /* pam_syslog(handle, LOG_DEBUG, "pam-systemd done"); */
 744
 745         r = PAM_SUCCESS;
 746
 747 finish:
 748         if (lock_fd >= 0)
 749                 close_nointr_nofail(lock_fd);
 750
 751         free(session_path);
 752         free(nosession_path);
 753         free(user_path);
 754
 755         strv_free(controllers);
 756         strv_free(kill_exclude_users);
 757         strv_free(kill_only_users);
 758
 759         free(cgroup_user_tree);
 760
 761         return r;
 762 }