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