lib/libdevmapper.c

   1 #include <sys/ioctl.h>
   2 #include <sys/stat.h>
   3 #include <stdio.h>
   4 #include <dirent.h>
   5 #include <errno.h>
   6 #include <libdevmapper.h>
   7 #include <fcntl.h>
   8 #include <linux/fs.h>
   9 #include <uuid/uuid.h>
  10
  11 #include "internal.h"
  12 #include "luks.h"
  13
  14 #define DEVICE_DIR              "/dev"
  15 #define DM_UUID_LEN             129
  16 #define DM_UUID_PREFIX          "CRYPT-"
  17 #define DM_UUID_PREFIX_LEN      6
  18 #define DM_CRYPT_TARGET         "crypt"
  19 #define RETRY_COUNT             5
  20
  21 static int _dm_use_count = 0;
  22 static struct crypt_device *_context = NULL;
  23
  24 /* Compatibility for old device-mapper without udev support */
  25 #ifndef HAVE_DM_TASK_SET_COOKIE
  26 #define CRYPT_TEMP_UDEV_FLAGS   0
  27 static int dm_task_set_cookie(struct dm_task *dmt, uint32_t *cookie, uint16_t flags) { return 0; }
  28 static int dm_udev_wait(uint32_t cookie) { return 0; };
  29 #else
  30 #define CRYPT_TEMP_UDEV_FLAGS   DM_UDEV_DISABLE_SUBSYSTEM_RULES_FLAG | \
  31                                 DM_UDEV_DISABLE_DISK_RULES_FLAG | \
  32                                 DM_UDEV_DISABLE_OTHER_RULES_FLAG
  33 #endif
  34
  35 static int _dm_use_udev()
  36 {
  37 #ifdef USE_UDEV /* cannot be enabled if devmapper is too old */
  38         return dm_udev_get_sync_support();
  39 #else
  40         return 0;
  41 #endif
  42 }
  43
  44 static void set_dm_error(int level, const char *file, int line,
  45                          const char *f, ...)
  46 {
  47         char *msg = NULL;
  48         va_list va;
  49
  50         va_start(va, f);
  51         if (vasprintf(&msg, f, va) > 0) {
  52                 if (level < 4) {
  53                         log_err(_context, msg);
  54                         log_err(_context, "\n");
  55                 } else
  56                         log_dbg(msg);
  57         }
  58         free(msg);
  59         va_end(va);
  60 }
  61
  62 static int _dm_simple(int task, const char *name, int udev_wait);
  63
  64 int dm_init(struct crypt_device *context, int check_kernel)
  65 {
  66         if (!_dm_use_count++) {
  67                 log_dbg("Initialising device-mapper backend%s, UDEV is %sabled.",
  68                         check_kernel ? "" : " (NO kernel check requested)",
  69                         _dm_use_udev() ? "en" : "dis");
  70                 if (check_kernel && !_dm_simple(DM_DEVICE_LIST_VERSIONS, NULL, 0)) {
  71                         log_err(context, _("Cannot initialize device-mapper. Is dm_mod kernel module loaded?\n"));
  72                         return -1;
  73                 }
  74                 if (getuid() || geteuid())
  75                         log_dbg(("WARNING: Running as a non-root user. Functionality may be unavailable."));
  76                 dm_log_init(set_dm_error);
  77                 dm_log_init_verbose(10);
  78         }
  79
  80         // FIXME: global context is not safe
  81         if (context)
  82                 _context = context;
  83
  84         return 1;       /* unsafe memory */
  85 }
  86
  87 void dm_exit(void)
  88 {
  89         if (_dm_use_count && (!--_dm_use_count)) {
  90                 log_dbg("Releasing device-mapper backend.");
  91                 dm_log_init_verbose(0);
  92                 dm_log_init(NULL);
  93                 dm_lib_release();
  94                 _context = NULL;
  95         }
  96 }
  97
  98 static char *__lookup_dev(char *path, dev_t dev, int dir_level, const int max_level)
  99 {
 100         struct dirent *entry;
 101         struct stat st;
 102         char *ptr;
 103         char *result = NULL;
 104         DIR *dir;
 105         int space;
 106
 107         /* Ignore strange nested directories */
 108         if (dir_level > max_level)
 109                 return NULL;
 110
 111         path[PATH_MAX - 1] = '\0';
 112         ptr = path + strlen(path);
 113         *ptr++ = '/';
 114         *ptr = '\0';
 115         space = PATH_MAX - (ptr - path);
 116
 117         dir = opendir(path);
 118         if (!dir)
 119                 return NULL;
 120
 121         while((entry = readdir(dir))) {
 122                 if (entry->d_name[0] == '.' ||
 123                     !strncmp(entry->d_name, "..", 2))
 124                         continue;
 125
 126                 strncpy(ptr, entry->d_name, space);
 127                 if (lstat(path, &st) < 0)
 128                         continue;
 129
 130                 if (S_ISDIR(st.st_mode)) {
 131                         result = __lookup_dev(path, dev, dir_level + 1, max_level);
 132                         if (result)
 133                                 break;
 134                 } else if (S_ISBLK(st.st_mode)) {
 135                         /* workaround: ignore dm-X devices, these are internal kernel names */
 136                         if (dir_level == 0 && !strncmp(entry->d_name, "dm-", 3))
 137                                 continue;
 138                         if (st.st_rdev == dev) {
 139                                 result = strdup(path);
 140                                 break;
 141                         }
 142                 }
 143         }
 144
 145         closedir(dir);
 146         return result;
 147 }
 148
 149 static char *lookup_dev(const char *dev_id)
 150 {
 151         uint32_t major, minor;
 152         dev_t dev;
 153         char *result, buf[PATH_MAX + 1];
 154
 155         if (sscanf(dev_id, "%" PRIu32 ":%" PRIu32, &major, &minor) != 2)
 156                 return NULL;
 157
 158         dev = makedev(major, minor);
 159         strncpy(buf, DEVICE_DIR, PATH_MAX);
 160         buf[PATH_MAX] = '\0';
 161
 162         /* First try low level device */
 163         if ((result = __lookup_dev(buf, dev, 0, 0)))
 164                 return result;
 165
 166         /* If it is dm, try DM dir  */
 167         if (dm_is_dm_major(major)) {
 168                 strncpy(buf, dm_dir(), PATH_MAX);
 169                 if ((result = __lookup_dev(buf, dev, 0, 0)))
 170                         return result;
 171         }
 172
 173         strncpy(buf, DEVICE_DIR, PATH_MAX);
 174         result = __lookup_dev(buf, dev, 0, 4);
 175
 176         /* If not found, return major:minor */
 177         return result ?: strdup(dev_id);
 178 }
 179
 180 static int _dev_read_ahead(const char *dev, uint32_t *read_ahead)
 181 {
 182         int fd, r = 0;
 183         long read_ahead_long;
 184
 185         if ((fd = open(dev, O_RDONLY)) < 0)
 186                 return 0;
 187
 188         r = ioctl(fd, BLKRAGET, &read_ahead_long) ? 0 : 1;
 189         close(fd);
 190
 191         if (r)
 192                 *read_ahead = (uint32_t) read_ahead_long;
 193
 194         return r;
 195 }
 196
 197 static void hex_key(char *hexkey, size_t key_size, const char *key)
 198 {
 199         int i;
 200
 201         for(i = 0; i < key_size; i++)
 202                 sprintf(&hexkey[i * 2], "%02x", (unsigned char)key[i]);
 203 }
 204
 205 static char *get_params(const char *device, uint64_t skip, uint64_t offset,
 206                         const char *cipher, size_t key_size, const char *key)
 207 {
 208         char *params;
 209         char *hexkey;
 210
 211         hexkey = safe_alloc(key_size * 2 + 1);
 212         if (!hexkey)
 213                 return NULL;
 214
 215         hex_key(hexkey, key_size, key);
 216
 217         params = safe_alloc(strlen(hexkey) + strlen(cipher) + strlen(device) + 64);
 218         if (!params)
 219                 goto out;
 220
 221         sprintf(params, "%s %s %" PRIu64 " %s %" PRIu64,
 222                 cipher, hexkey, skip, device, offset);
 223
 224 out:
 225         safe_free(hexkey);
 226         return params;
 227 }
 228
 229 /* DM helpers */
 230 static int _dm_simple(int task, const char *name, int udev_wait)
 231 {
 232         int r = 0;
 233         struct dm_task *dmt;
 234         uint32_t cookie = 0;
 235
 236         if (!_dm_use_udev())
 237                 udev_wait = 0;
 238
 239         if (!(dmt = dm_task_create(task)))
 240                 return 0;
 241
 242         if (name && !dm_task_set_name(dmt, name))
 243                 goto out;
 244
 245         if (udev_wait && !dm_task_set_cookie(dmt, &cookie, 0))
 246                 goto out;
 247
 248         r = dm_task_run(dmt);
 249
 250         if (udev_wait)
 251                 (void)dm_udev_wait(cookie);
 252
 253       out:
 254         dm_task_destroy(dmt);
 255         return r;
 256 }
 257
 258 static int _error_device(const char *name, size_t size)
 259 {
 260         struct dm_task *dmt;
 261         int r = 0;
 262
 263         if (!(dmt = dm_task_create(DM_DEVICE_RELOAD)))
 264                 return 0;
 265
 266         if (!dm_task_set_name(dmt, name))
 267                 goto error;
 268
 269         if (!dm_task_add_target(dmt, UINT64_C(0), size, "error", ""))
 270                 goto error;
 271
 272         if (!dm_task_set_ro(dmt))
 273                 goto error;
 274
 275         if (!dm_task_no_open_count(dmt))
 276                 goto error;
 277
 278         if (!dm_task_run(dmt))
 279                 goto error;
 280
 281         if (!_dm_simple(DM_DEVICE_RESUME, name, 1)) {
 282                 _dm_simple(DM_DEVICE_CLEAR, name, 0);
 283                 goto error;
 284         }
 285
 286         r = 1;
 287
 288 error:
 289         dm_task_destroy(dmt);
 290         return r;
 291 }
 292
 293 int dm_remove_device(const char *name, int force, uint64_t size)
 294 {
 295         int r = -EINVAL;
 296         int retries = force ? RETRY_COUNT : 1;
 297         int error_target = 0;
 298
 299         if (!name || (force && !size))
 300                 return -EINVAL;
 301
 302         do {
 303                 r = _dm_simple(DM_DEVICE_REMOVE, name, 1) ? 0 : -EINVAL;
 304                 if (--retries && r) {
 305                         log_dbg("WARNING: other process locked internal device %s, %s.",
 306                                 name, retries ? "retrying remove" : "giving up");
 307                         if (force && (crypt_get_debug_level() == CRYPT_LOG_DEBUG))
 308                                 debug_processes_using_device(name);
 309                         sleep(1);
 310                         if (force && !error_target) {
 311                                 /* If force flag is set, replace device with error, read-only target.
 312                                  * it should stop processes from reading it and also removed underlying
 313                                  * device from mapping, so it is usable again.
 314                                  * Force flag should be used only for temporary devices, which are
 315                                  * intended to work inside cryptsetup only!
 316                                  * Anyway, if some process try to read temporary cryptsetup device,
 317                                  * it is bug - no other process should try touch it (e.g. udev).
 318                                  */
 319                                 _error_device(name, size);
 320                                 error_target = 1;
 321                         }
 322                 }
 323         } while (r == -EINVAL && retries);
 324
 325         dm_task_update_nodes();
 326
 327         return r;
 328 }
 329
 330 #define UUID_LEN 37 /* 36 + \0, libuuid ... */
 331 /*
 332  * UUID has format: CRYPT-<devicetype>-[<uuid>-]<device name>
 333  * CRYPT-PLAIN-name
 334  * CRYPT-LUKS1-00000000000000000000000000000000-name
 335  * CRYPT-TEMP-name
 336  */
 337 static void dm_prepare_uuid(const char *name, const char *type, const char *uuid, char *buf, size_t buflen)
 338 {
 339         char *ptr, uuid2[UUID_LEN] = {0};
 340         uuid_t uu;
 341         int i = 0;
 342
 343         /* Remove '-' chars */
 344         if (uuid && !uuid_parse(uuid, uu)) {
 345                 for (ptr = uuid2, i = 0; i < UUID_LEN; i++)
 346                         if (uuid[i] != '-') {
 347                                 *ptr = uuid[i];
 348                                 ptr++;
 349                         }
 350         }
 351
 352         i = snprintf(buf, buflen, DM_UUID_PREFIX "%s%s%s%s%s",
 353                 type ?: "", type ? "-" : "",
 354                 uuid2[0] ? uuid2 : "", uuid2[0] ? "-" : "",
 355                 name);
 356
 357         log_dbg("DM-UUID is %s", buf);
 358         if (i >= buflen)
 359                 log_err(NULL, _("DM-UUID for device %s was truncated.\n"), name);
 360 }
 361
 362 int dm_create_device(const char *name,
 363                      const char *device,
 364                      const char *cipher,
 365                      const char *type,
 366                      const char *uuid,
 367                      uint64_t size,
 368                      uint64_t skip,
 369                      uint64_t offset,
 370                      size_t key_size,
 371                      const char *key,
 372                      int read_only,
 373                      int reload)
 374 {
 375         struct dm_task *dmt = NULL;
 376         struct dm_info dmi;
 377         char *params = NULL;
 378         char *error = NULL;
 379         char dev_uuid[DM_UUID_LEN] = {0};
 380         int r = -EINVAL;
 381         uint32_t read_ahead = 0;
 382         uint32_t cookie = 0;
 383         uint16_t udev_flags = 0;
 384
 385         params = get_params(device, skip, offset, cipher, key_size, key);
 386         if (!params)
 387                 goto out_no_removal;
 388
 389         if (type && !strncmp(type, "TEMP", 4))
 390                 udev_flags = CRYPT_TEMP_UDEV_FLAGS;
 391
 392         /* All devices must have DM_UUID, only resize on old device is exception */
 393         if (reload) {
 394                 if (!(dmt = dm_task_create(DM_DEVICE_RELOAD)))
 395                         goto out_no_removal;
 396
 397                 if (!dm_task_set_name(dmt, name))
 398                         goto out_no_removal;
 399         } else {
 400                 dm_prepare_uuid(name, type, uuid, dev_uuid, sizeof(dev_uuid));
 401
 402                 if (!(dmt = dm_task_create(DM_DEVICE_CREATE)))
 403                         goto out_no_removal;
 404
 405                 if (!dm_task_set_name(dmt, name))
 406                         goto out_no_removal;
 407
 408                 if (!dm_task_set_uuid(dmt, dev_uuid))
 409                         goto out_no_removal;
 410
 411                 if (_dm_use_udev() && !dm_task_set_cookie(dmt, &cookie, udev_flags))
 412                         goto out_no_removal;
 413         }
 414
 415         if (read_only && !dm_task_set_ro(dmt))
 416                 goto out_no_removal;
 417         if (!dm_task_add_target(dmt, 0, size, DM_CRYPT_TARGET, params))
 418                 goto out_no_removal;
 419
 420 #ifdef DM_READ_AHEAD_MINIMUM_FLAG
 421         if (_dev_read_ahead(device, &read_ahead) &&
 422             !dm_task_set_read_ahead(dmt, read_ahead, DM_READ_AHEAD_MINIMUM_FLAG))
 423                 goto out_no_removal;
 424 #endif
 425
 426         if (!dm_task_run(dmt))
 427                 goto out_no_removal;
 428
 429         if (reload) {
 430                 dm_task_destroy(dmt);
 431                 if (!(dmt = dm_task_create(DM_DEVICE_RESUME)))
 432                         goto out;
 433                 if (!dm_task_set_name(dmt, name))
 434                         goto out;
 435                 if (uuid && !dm_task_set_uuid(dmt, dev_uuid))
 436                         goto out;
 437                 if (_dm_use_udev() && !dm_task_set_cookie(dmt, &cookie, udev_flags))
 438                         goto out;
 439                 if (!dm_task_run(dmt))
 440                         goto out;
 441         }
 442
 443         if (!dm_task_get_info(dmt, &dmi))
 444                 goto out;
 445
 446         r = 0;
 447 out:
 448         if (_dm_use_udev()) {
 449                 (void)dm_udev_wait(cookie);
 450                 cookie = 0;
 451         }
 452
 453         if (r < 0 && !reload) {
 454                 if (get_error())
 455                         error = strdup(get_error());
 456
 457                 dm_remove_device(name, 0, 0);
 458
 459                 if (error) {
 460                         set_error(error);
 461                         free(error);
 462                 }
 463         }
 464
 465 out_no_removal:
 466         if (cookie && _dm_use_udev())
 467                 (void)dm_udev_wait(cookie);
 468
 469         if (params)
 470                 safe_free(params);
 471         if (dmt)
 472                 dm_task_destroy(dmt);
 473
 474         dm_task_update_nodes();
 475         return r;
 476 }
 477
 478 int dm_status_device(const char *name)
 479 {
 480         struct dm_task *dmt;
 481         struct dm_info dmi;
 482         uint64_t start, length;
 483         char *target_type, *params;
 484         void *next = NULL;
 485         int r = -EINVAL;
 486
 487         if (!(dmt = dm_task_create(DM_DEVICE_STATUS)))
 488                 return -EINVAL;
 489
 490         if (!dm_task_set_name(dmt, name)) {
 491                 r = -EINVAL;
 492                 goto out;
 493         }
 494
 495         if (!dm_task_run(dmt)) {
 496                 r = -EINVAL;
 497                 goto out;
 498         }
 499
 500         if (!dm_task_get_info(dmt, &dmi)) {
 501                 r = -EINVAL;
 502                 goto out;
 503         }
 504
 505         if (!dmi.exists) {
 506                 r = -ENODEV;
 507                 goto out;
 508         }
 509
 510         next = dm_get_next_target(dmt, next, &start, &length,
 511                                   &target_type, &params);
 512         if (!target_type || strcmp(target_type, DM_CRYPT_TARGET) != 0 ||
 513             start != 0 || next)
 514                 r = -EINVAL;
 515         else
 516                 r = (dmi.open_count > 0);
 517 out:
 518         if (dmt)
 519                 dm_task_destroy(dmt);
 520
 521         return r;
 522 }
 523
 524 int dm_query_device(const char *name,
 525                     char **device,
 526                     uint64_t *size,
 527                     uint64_t *skip,
 528                     uint64_t *offset,
 529                     char **cipher,
 530                     int *key_size,
 531                     char **key,
 532                     int *read_only,
 533                     int *suspended,
 534                     char **uuid)
 535 {
 536         struct dm_task *dmt;
 537         struct dm_info dmi;
 538         uint64_t start, length, val64;
 539         char *target_type, *params, *rcipher, *key_, *rdevice, *endp, buffer[3], *tmp_uuid;
 540         void *next = NULL;
 541         int i, r = -EINVAL;
 542
 543         if (!(dmt = dm_task_create(DM_DEVICE_TABLE)))
 544                 goto out;
 545         if (!dm_task_set_name(dmt, name))
 546                 goto out;
 547         r = -ENODEV;
 548         if (!dm_task_run(dmt))
 549                 goto out;
 550
 551         r = -EINVAL;
 552         if (!dm_task_get_info(dmt, &dmi))
 553                 goto out;
 554
 555         if (!dmi.exists) {
 556                 r = -ENODEV;
 557                 goto out;
 558         }
 559
 560         next = dm_get_next_target(dmt, next, &start, &length,
 561                                   &target_type, &params);
 562         if (!target_type || strcmp(target_type, DM_CRYPT_TARGET) != 0 ||
 563             start != 0 || next)
 564                 goto out;
 565
 566         if (size)
 567                 *size = length;
 568
 569         rcipher = strsep(&params, " ");
 570         /* cipher */
 571         if (cipher)
 572                 *cipher = strdup(rcipher);
 573
 574         /* skip */
 575         key_ = strsep(&params, " ");
 576         if (!params)
 577                 goto out;
 578         val64 = strtoull(params, &params, 10);
 579         if (*params != ' ')
 580                 goto out;
 581         params++;
 582         if (skip)
 583                 *skip = val64;
 584
 585         /* device */
 586         rdevice = strsep(&params, " ");
 587         if (device)
 588                 *device = lookup_dev(rdevice);
 589
 590         /*offset */
 591         if (!params)
 592                 goto out;
 593         val64 = strtoull(params, &params, 10);
 594         if (*params)
 595                 goto out;
 596         if (offset)
 597                 *offset = val64;
 598
 599         /* key_size */
 600         if (key_size)
 601                 *key_size = strlen(key_) / 2;
 602
 603         /* key */
 604         if (key_size && key) {
 605                 *key = safe_alloc(*key_size);
 606                 if (!*key) {
 607                         r = -ENOMEM;
 608                         goto out;
 609                 }
 610
 611                 buffer[2] = '\0';
 612                 for(i = 0; i < *key_size; i++) {
 613                         memcpy(buffer, &key_[i * 2], 2);
 614                         (*key)[i] = strtoul(buffer, &endp, 16);
 615                         if (endp != &buffer[2]) {
 616                                 safe_free(key);
 617                                 *key = NULL;
 618                                 goto out;
 619                         }
 620                 }
 621         }
 622         memset(key_, 0, strlen(key_));
 623
 624         if (read_only)
 625                 *read_only = dmi.read_only;
 626
 627         if (suspended)
 628                 *suspended = dmi.suspended;
 629
 630         if (uuid && (tmp_uuid = (char*)dm_task_get_uuid(dmt)) &&
 631             !strncmp(tmp_uuid, DM_UUID_PREFIX, DM_UUID_PREFIX_LEN))
 632                 *uuid = strdup(tmp_uuid + DM_UUID_PREFIX_LEN);
 633
 634         r = (dmi.open_count > 0);
 635 out:
 636         if (dmt)
 637                 dm_task_destroy(dmt);
 638
 639         return r;
 640 }
 641
 642 static int _dm_message(const char *name, const char *msg)
 643 {
 644         int r = 0;
 645         struct dm_task *dmt;
 646
 647         if (!(dmt = dm_task_create(DM_DEVICE_TARGET_MSG)))
 648                 return 0;
 649
 650         if (name && !dm_task_set_name(dmt, name))
 651                 goto out;
 652
 653         if (!dm_task_set_sector(dmt, (uint64_t) 0))
 654                 goto out;
 655
 656         if (!dm_task_set_message(dmt, msg))
 657                 goto out;
 658
 659         r = dm_task_run(dmt);
 660
 661       out:
 662         dm_task_destroy(dmt);
 663         return r;
 664 }
 665
 666 int dm_suspend_and_wipe_key(const char *name)
 667 {
 668         if (!_dm_simple(DM_DEVICE_SUSPEND, name, 0))
 669                 return -EINVAL;
 670
 671         if (!_dm_message(name, "key wipe")) {
 672                 _dm_simple(DM_DEVICE_RESUME, name, 1);
 673                 return -EINVAL;
 674         }
 675
 676         return 0;
 677 }
 678
 679 int dm_resume_and_reinstate_key(const char *name,
 680                                 size_t key_size,
 681                                 const char *key)
 682 {
 683         int msg_size = key_size * 2 + 10; // key set <key>
 684         char *msg;
 685         int r = 0;
 686
 687         msg = safe_alloc(msg_size);
 688         if (!msg)
 689                 return -ENOMEM;
 690
 691         memset(msg, 0, msg_size);
 692         strcpy(msg, "key set ");
 693         hex_key(&msg[8], key_size, key);
 694
 695         if (!_dm_message(name, msg) ||
 696             !_dm_simple(DM_DEVICE_RESUME, name, 1))
 697                 r = -EINVAL;
 698
 699         safe_free(msg);
 700         return r;
 701 }
 702
 703 const char *dm_get_dir(void)
 704 {
 705         return dm_dir();
 706 }