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                         if (force && (crypt_get_debug_level() == CRYPT_LOG_DEBUG))
 253                                 debug_processes_using_device(name);
 254                         sleep(1);
 255                         if (force && !error_target) {
 256                                 /* If force flag is set, replace device with error, read-only target.
 257                                  * it should stop processes from reading it and also removed underlying
 258                                  * device from mapping, so it is usable again.
 259                                  * Force flag should be used only for temporary devices, which are
 260                                  * intended to work inside cryptsetup only!
 261                                  * Anyway, if some process try to read temporary cryptsetup device,
 262                                  * it is bug - no other process should try touch it (e.g. udev).
 263                                  */
 264                                 _error_device(name, size);
 265                                 error_target = 1;
 266                         }
 267                 }
 268         } while (r == -EINVAL && retries);
 269
 270         dm_task_update_nodes();
 271
 272         return r;
 273 }
 274
 275 #define UUID_LEN 37 /* 36 + \0, libuuid ... */
 276 /*
 277  * UUID has format: CRYPT-<devicetype>-[<uuid>-]<device name>
 278  * CRYPT-PLAIN-name
 279  * CRYPT-LUKS1-00000000000000000000000000000000-name
 280  * CRYPT-TEMP-name
 281  */
 282 static void dm_prepare_uuid(const char *name, const char *type, const char *uuid, char *buf, size_t buflen)
 283 {
 284         char *ptr, uuid2[UUID_LEN] = {0};
 285         uuid_t uu;
 286         int i = 0;
 287
 288         /* Remove '-' chars */
 289         if (uuid && !uuid_parse(uuid, uu)) {
 290                 for (ptr = uuid2, i = 0; i < UUID_LEN; i++)
 291                         if (uuid[i] != '-') {
 292                                 *ptr = uuid[i];
 293                                 ptr++;
 294                         }
 295         }
 296
 297         i = snprintf(buf, buflen, DM_UUID_PREFIX "%s%s%s%s%s",
 298                 type ?: "", type ? "-" : "",
 299                 uuid2[0] ? uuid2 : "", uuid2[0] ? "-" : "",
 300                 name);
 301
 302         log_dbg("DM-UUID is %s", buf);
 303         if (i >= buflen)
 304                 log_err(NULL, _("DM-UUID for device %s was truncated.\n"), name);
 305 }
 306
 307 int dm_create_device(const char *name,
 308                      const char *device,
 309                      const char *cipher,
 310                      const char *type,
 311                      const char *uuid,
 312                      uint64_t size,
 313                      uint64_t skip,
 314                      uint64_t offset,
 315                      size_t key_size,
 316                      const char *key,
 317                      int read_only,
 318                      int reload)
 319 {
 320         struct dm_task *dmt = NULL;
 321         struct dm_task *dmt_query = NULL;
 322         struct dm_info dmi;
 323         char *params = NULL;
 324         char *error = NULL;
 325         char dev_uuid[DM_UUID_LEN] = {0};
 326         int r = -EINVAL;
 327         uint32_t read_ahead = 0;
 328
 329         params = get_params(device, skip, offset, cipher, key_size, key);
 330         if (!params)
 331                 goto out_no_removal;
 332
 333         /* All devices must have DM_UUID, only resize on old device is exception */
 334         if (reload) {
 335                 if (!(dmt = dm_task_create(DM_DEVICE_RELOAD)))
 336                         goto out_no_removal;
 337
 338                 if (!dm_task_set_name(dmt, name))
 339                         goto out_no_removal;
 340         } else {
 341                 dm_prepare_uuid(name, type, uuid, dev_uuid, sizeof(dev_uuid));
 342
 343                 if (!(dmt = dm_task_create(DM_DEVICE_CREATE)))
 344                         goto out_no_removal;
 345
 346                 if (!dm_task_set_name(dmt, name))
 347                         goto out_no_removal;
 348
 349                 if (!dm_task_set_uuid(dmt, dev_uuid))
 350                         goto out_no_removal;
 351         }
 352
 353
 354         if (read_only && !dm_task_set_ro(dmt))
 355                 goto out_no_removal;
 356         if (!dm_task_add_target(dmt, 0, size, DM_CRYPT_TARGET, params))
 357                 goto out_no_removal;
 358
 359 #ifdef DM_READ_AHEAD_MINIMUM_FLAG
 360         if (_dev_read_ahead(device, &read_ahead) &&
 361             !dm_task_set_read_ahead(dmt, read_ahead, DM_READ_AHEAD_MINIMUM_FLAG))
 362                 goto out_no_removal;
 363 #endif
 364
 365         if (!dm_task_run(dmt))
 366                 goto out_no_removal;
 367
 368         if (reload) {
 369                 dm_task_destroy(dmt);
 370                 if (!(dmt = dm_task_create(DM_DEVICE_RESUME)))
 371                         goto out;
 372                 if (!dm_task_set_name(dmt, name))
 373                         goto out;
 374                 if (uuid && !dm_task_set_uuid(dmt, dev_uuid))
 375                         goto out;
 376                 if (!dm_task_run(dmt))
 377                         goto out;
 378         }
 379
 380         if (!dm_task_get_info(dmt, &dmi))
 381                 goto out;
 382
 383         r = 0;
 384 out:
 385         if (r < 0 && !reload) {
 386                 if (get_error())
 387                         error = strdup(get_error());
 388
 389                 dm_remove_device(name, 0, 0);
 390
 391                 if (error) {
 392                         set_error(error);
 393                         free(error);
 394                 }
 395         }
 396
 397 out_no_removal:
 398         if (params)
 399                 safe_free(params);
 400         if (dmt)
 401                 dm_task_destroy(dmt);
 402         if(dmt_query)
 403                 dm_task_destroy(dmt_query);
 404         dm_task_update_nodes();
 405         return r;
 406 }
 407
 408 int dm_status_device(const char *name)
 409 {
 410         struct dm_task *dmt;
 411         struct dm_info dmi;
 412         uint64_t start, length;
 413         char *target_type, *params;
 414         void *next = NULL;
 415         int r = -EINVAL;
 416
 417         if (!(dmt = dm_task_create(DM_DEVICE_STATUS)))
 418                 return -EINVAL;
 419
 420         if (!dm_task_set_name(dmt, name)) {
 421                 r = -EINVAL;
 422                 goto out;
 423         }
 424
 425         if (!dm_task_run(dmt)) {
 426                 r = -EINVAL;
 427                 goto out;
 428         }
 429
 430         if (!dm_task_get_info(dmt, &dmi)) {
 431                 r = -EINVAL;
 432                 goto out;
 433         }
 434
 435         if (!dmi.exists) {
 436                 r = -ENODEV;
 437                 goto out;
 438         }
 439
 440         next = dm_get_next_target(dmt, next, &start, &length,
 441                                   &target_type, &params);
 442         if (!target_type || strcmp(target_type, DM_CRYPT_TARGET) != 0 ||
 443             start != 0 || next)
 444                 r = -EINVAL;
 445         else
 446                 r = (dmi.open_count > 0);
 447 out:
 448         if (dmt)
 449                 dm_task_destroy(dmt);
 450
 451         return r;
 452 }
 453
 454 int dm_query_device(const char *name,
 455                     char **device,
 456                     uint64_t *size,
 457                     uint64_t *skip,
 458                     uint64_t *offset,
 459                     char **cipher,
 460                     int *key_size,
 461                     char **key,
 462                     int *read_only,
 463                     int *suspended,
 464                     char **uuid)
 465 {
 466         struct dm_task *dmt;
 467         struct dm_info dmi;
 468         uint64_t start, length, val64;
 469         char *target_type, *params, *rcipher, *key_, *rdevice, *endp, buffer[3], *tmp_uuid;
 470         void *next = NULL;
 471         int i, r = -EINVAL;
 472
 473         if (!(dmt = dm_task_create(DM_DEVICE_TABLE)))
 474                 goto out;
 475         if (!dm_task_set_name(dmt, name))
 476                 goto out;
 477         r = -ENODEV;
 478         if (!dm_task_run(dmt))
 479                 goto out;
 480
 481         r = -EINVAL;
 482         if (!dm_task_get_info(dmt, &dmi))
 483                 goto out;
 484
 485         if (!dmi.exists) {
 486                 r = -ENODEV;
 487                 goto out;
 488         }
 489
 490         next = dm_get_next_target(dmt, next, &start, &length,
 491                                   &target_type, &params);
 492         if (!target_type || strcmp(target_type, DM_CRYPT_TARGET) != 0 ||
 493             start != 0 || next)
 494                 goto out;
 495
 496         if (size)
 497                 *size = length;
 498
 499         rcipher = strsep(&params, " ");
 500         /* cipher */
 501         if (cipher)
 502                 *cipher = strdup(rcipher);
 503
 504         /* skip */
 505         key_ = strsep(&params, " ");
 506         if (!params)
 507                 goto out;
 508         val64 = strtoull(params, &params, 10);
 509         if (*params != ' ')
 510                 goto out;
 511         params++;
 512         if (skip)
 513                 *skip = val64;
 514
 515         /* device */
 516         rdevice = strsep(&params, " ");
 517         if (device)
 518                 *device = lookup_dev(rdevice);
 519
 520         /*offset */
 521         if (!params)
 522                 goto out;
 523         val64 = strtoull(params, &params, 10);
 524         if (*params)
 525                 goto out;
 526         if (offset)
 527                 *offset = val64;
 528
 529         /* key_size */
 530         if (key_size)
 531                 *key_size = strlen(key_) / 2;
 532
 533         /* key */
 534         if (key_size && key) {
 535                 *key = safe_alloc(*key_size);
 536                 if (!*key) {
 537                         r = -ENOMEM;
 538                         goto out;
 539                 }
 540
 541                 buffer[2] = '\0';
 542                 for(i = 0; i < *key_size; i++) {
 543                         memcpy(buffer, &key_[i * 2], 2);
 544                         (*key)[i] = strtoul(buffer, &endp, 16);
 545                         if (endp != &buffer[2]) {
 546                                 safe_free(key);
 547                                 *key = NULL;
 548                                 goto out;
 549                         }
 550                 }
 551         }
 552         memset(key_, 0, strlen(key_));
 553
 554         if (read_only)
 555                 *read_only = dmi.read_only;
 556
 557         if (suspended)
 558                 *suspended = dmi.suspended;
 559
 560         if (uuid && (tmp_uuid = (char*)dm_task_get_uuid(dmt)) &&
 561             !strncmp(tmp_uuid, DM_UUID_PREFIX, DM_UUID_PREFIX_LEN))
 562                 *uuid = strdup(tmp_uuid + DM_UUID_PREFIX_LEN);
 563
 564         r = (dmi.open_count > 0);
 565 out:
 566         if (dmt)
 567                 dm_task_destroy(dmt);
 568
 569         return r;
 570 }
 571
 572 static int _dm_message(const char *name, const char *msg)
 573 {
 574         int r = 0;
 575         struct dm_task *dmt;
 576
 577         if (!(dmt = dm_task_create(DM_DEVICE_TARGET_MSG)))
 578                 return 0;
 579
 580         if (name && !dm_task_set_name(dmt, name))
 581                 goto out;
 582
 583         if (!dm_task_set_sector(dmt, (uint64_t) 0))
 584                 goto out;
 585
 586         if (!dm_task_set_message(dmt, msg))
 587                 goto out;
 588
 589         r = dm_task_run(dmt);
 590
 591       out:
 592         dm_task_destroy(dmt);
 593         return r;
 594 }
 595
 596 int dm_suspend_and_wipe_key(const char *name)
 597 {
 598         if (!_dm_simple(DM_DEVICE_SUSPEND, name))
 599                 return -EINVAL;
 600
 601         if (!_dm_message(name, "key wipe")) {
 602                 _dm_simple(DM_DEVICE_RESUME, name);
 603                 return -EINVAL;
 604         }
 605
 606         return 0;
 607 }
 608
 609 int dm_resume_and_reinstate_key(const char *name,
 610                                 size_t key_size,
 611                                 const char *key)
 612 {
 613         int msg_size = key_size * 2 + 10; // key set <key>
 614         char *msg;
 615         int r = 0;
 616
 617         msg = safe_alloc(msg_size);
 618         if (!msg)
 619                 return -ENOMEM;
 620
 621         memset(msg, 0, msg_size);
 622         strcpy(msg, "key set ");
 623         hex_key(&msg[8], key_size, key);
 624
 625         if (!_dm_message(name, msg) ||
 626             !_dm_simple(DM_DEVICE_RESUME, name))
 627                 r = -EINVAL;
 628
 629         safe_free(msg);
 630         return r;
 631 }
 632
 633 const char *dm_get_dir(void)
 634 {
 635         return dm_dir();
 636 }