lib/libdevmapper.c

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