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