lib/libdevmapper.c

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