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