lib/libdevmapper.c

   1 #include <sys/ioctl.h>
   2 #include <dirent.h>
   3 #include <errno.h>
   4 #include <libdevmapper.h>
   5 #include <fcntl.h>
   6 #include <linux/fs.h>
   7
   8 #include "internal.h"
   9 #include "luks.h"
  10
  11 #define DEVICE_DIR              "/dev"
  12 #define DM_UUID_PREFIX          "CRYPT-"
  13 #define DM_UUID_PREFIX_LEN      6
  14 #define DM_UUID_LEN             UUID_STRING_L
  15 #define DM_CRYPT_TARGET         "crypt"
  16 #define RETRY_COUNT             5
  17
  18 static int _dm_use_count = 0;
  19 static struct crypt_device *_context = NULL;
  20
  21 static void set_dm_error(int level, const char *file, int line,
  22                          const char *f, ...)
  23 {
  24         va_list va;
  25
  26         if (level > 3)
  27                 return;
  28
  29         va_start(va, f);
  30         set_error_va(f, va);
  31         va_end(va);
  32 }
  33
  34 static int _dm_simple(int task, const char *name);
  35
  36 int dm_init(struct crypt_device *context, int check_kernel)
  37 {
  38         if (!_dm_use_count++) {
  39                 if (check_kernel && !_dm_simple(DM_DEVICE_LIST_VERSIONS, NULL))
  40                         return -1;
  41                 dm_log_init(set_dm_error);
  42                 dm_log_init_verbose(10);
  43         }
  44
  45         if (context)
  46                 _context = context;
  47
  48         return 1;       /* unsafe memory */
  49 }
  50
  51 void dm_exit(void)
  52 {
  53         if (_dm_use_count && (!--_dm_use_count)) {
  54                 dm_log_init_verbose(0);
  55                 dm_log_init(NULL);
  56                 dm_lib_release();
  57                 _context = NULL;
  58         }
  59 }
  60
  61 static char *__lookup_dev(char *path, dev_t dev)
  62 {
  63         struct dirent *entry;
  64         struct stat st;
  65         char *ptr;
  66         char *result = NULL;
  67         DIR *dir;
  68         int space;
  69
  70         path[PATH_MAX - 1] = '\0';
  71         ptr = path + strlen(path);
  72         *ptr++ = '/';
  73         *ptr = '\0';
  74         space = PATH_MAX - (ptr - path);
  75
  76         dir = opendir(path);
  77         if (!dir)
  78                 return NULL;
  79
  80         while((entry = readdir(dir))) {
  81                 if (entry->d_name[0] == '.' &&
  82                     (entry->d_name[1] == '\0' || (entry->d_name[1] == '.' &&
  83                                                   entry->d_name[2] == '\0')))
  84                         continue;
  85
  86                 strncpy(ptr, entry->d_name, space);
  87                 if (lstat(path, &st) < 0)
  88                         continue;
  89
  90                 if (S_ISDIR(st.st_mode)) {
  91                         result = __lookup_dev(path, dev);
  92                         if (result)
  93                                 break;
  94                 } else if (S_ISBLK(st.st_mode)) {
  95                         if (st.st_rdev == dev) {
  96                                 result = strdup(path);
  97                                 break;
  98                         }
  99                 }
 100         }
 101
 102         closedir(dir);
 103
 104         return result;
 105 }
 106
 107 static char *lookup_dev(const char *dev)
 108 {
 109         uint32_t major, minor;
 110         char buf[PATH_MAX + 1];
 111
 112         if (sscanf(dev, "%" PRIu32 ":%" PRIu32, &major, &minor) != 2)
 113                 return NULL;
 114
 115         strncpy(buf, DEVICE_DIR, PATH_MAX);
 116         buf[PATH_MAX] = '\0';
 117
 118         return __lookup_dev(buf, makedev(major, minor));
 119 }
 120
 121 static int _dev_read_ahead(const char *dev, uint32_t *read_ahead)
 122 {
 123         int fd, r = 0;
 124         long read_ahead_long;
 125
 126         if ((fd = open(dev, O_RDONLY)) < 0)
 127                 return 0;
 128
 129         r = ioctl(fd, BLKRAGET, &read_ahead_long) ? 0 : 1;
 130         close(fd);
 131
 132         if (r)
 133                 *read_ahead = (uint32_t) read_ahead_long;
 134
 135         return r;
 136 }
 137
 138 static char *get_params(const char *device, uint64_t skip, uint64_t offset,
 139                         const char *cipher, size_t key_size, const char *key)
 140 {
 141         char *params;
 142         char *hexkey;
 143         int i;
 144
 145         hexkey = safe_alloc(key_size * 2 + 1);
 146         if (!hexkey)
 147                 return NULL;
 148
 149         for(i = 0; i < key_size; i++)
 150                 sprintf(&hexkey[i * 2], "%02x", (unsigned char)key[i]);
 151
 152         params = safe_alloc(strlen(hexkey) + strlen(cipher) + strlen(device) + 64);
 153         if (!params)
 154                 goto out;
 155
 156         sprintf(params, "%s %s %" PRIu64 " %s %" PRIu64,
 157                 cipher, hexkey, skip, device, offset);
 158
 159 out:
 160         safe_free(hexkey);
 161         return params;
 162 }
 163
 164 /* DM helpers */
 165 static int _dm_simple(int task, const char *name)
 166 {
 167         int r = 0;
 168         struct dm_task *dmt;
 169
 170         if (!(dmt = dm_task_create(task)))
 171                 return 0;
 172
 173         if (name && !dm_task_set_name(dmt, name))
 174                 goto out;
 175
 176         r = dm_task_run(dmt);
 177
 178       out:
 179         dm_task_destroy(dmt);
 180         return r;
 181 }
 182
 183 static int _error_device(const char *name, size_t size)
 184 {
 185         struct dm_task *dmt;
 186         int r = 0;
 187
 188         if (!(dmt = dm_task_create(DM_DEVICE_RELOAD)))
 189                 return 0;
 190
 191         if (!dm_task_set_name(dmt, name))
 192                 goto error;
 193
 194         if (!dm_task_add_target(dmt, UINT64_C(0), size, "error", ""))
 195                 goto error;
 196
 197         if (!dm_task_set_ro(dmt))
 198                 goto error;
 199
 200         if (!dm_task_no_open_count(dmt))
 201                 goto error;
 202
 203         if (!dm_task_run(dmt))
 204                 goto error;
 205
 206         if (!_dm_simple(DM_DEVICE_RESUME, name)) {
 207                 _dm_simple(DM_DEVICE_CLEAR, name);
 208                 goto error;
 209         }
 210
 211         r = 1;
 212
 213 error:
 214         dm_task_destroy(dmt);
 215         return r;
 216 }
 217
 218 int dm_remove_device(const char *name, int force, uint64_t size)
 219 {
 220         int r = -EINVAL;
 221         int retries = force ? RETRY_COUNT : 1;
 222
 223         if (!name || (force && !size))
 224                 return -EINVAL;
 225
 226         /* If force flag is set, replace device with error, read-only target.
 227          * it should stop processes from reading it and also removed underlying
 228          * device from mapping, so it is usable again.
 229          * Force flag should be used only for temporary devices, which are
 230          * intended to work inside cryptsetup only!
 231          * Anyway, if some process try to read temporary cryptsetup device,
 232          * it is bug - no other process should try touch it (e.g. udev).
 233          */
 234         if (force) {
 235                  _error_device(name, size);
 236                 retries = RETRY_COUNT;
 237         }
 238
 239         do {
 240                 r = _dm_simple(DM_DEVICE_REMOVE, name) ? 0 : -EINVAL;
 241                 if (--retries && r) {
 242                         sleep(1);
 243                 }
 244         } while (r == -EINVAL && retries);
 245
 246         dm_task_update_nodes();
 247
 248         return r;
 249 }
 250
 251 int dm_create_device(const char *name,
 252                      const char *device,
 253                      const char *cipher,
 254                      const char *uuid,
 255                      uint64_t size,
 256                      uint64_t skip,
 257                      uint64_t offset,
 258                      size_t key_size,
 259                      const char *key,
 260                      int read_only,
 261                      int reload)
 262 {
 263         struct dm_task *dmt = NULL;
 264         struct dm_task *dmt_query = NULL;
 265         struct dm_info dmi;
 266         char *params = NULL;
 267         char *error = NULL;
 268         char dev_uuid[DM_UUID_PREFIX_LEN + DM_UUID_LEN + 1] = {0};
 269         int r = -EINVAL;
 270         uint32_t read_ahead = 0;
 271
 272         params = get_params(device, skip, offset, cipher, key_size, key);
 273         if (!params)
 274                 goto out_no_removal;
 275
 276         if (uuid) {
 277                 strncpy(dev_uuid, DM_UUID_PREFIX, DM_UUID_PREFIX_LEN);
 278                 strncpy(dev_uuid + DM_UUID_PREFIX_LEN, uuid, DM_UUID_LEN);
 279                 dev_uuid[DM_UUID_PREFIX_LEN + DM_UUID_LEN] = '\0';
 280         }
 281
 282         if (!(dmt = dm_task_create(reload ? DM_DEVICE_RELOAD
 283                                           : DM_DEVICE_CREATE)))
 284                 goto out_no_removal;
 285         if (!dm_task_set_name(dmt, name))
 286                 goto out_no_removal;
 287         if (read_only && !dm_task_set_ro(dmt))
 288                 goto out_no_removal;
 289         if (!dm_task_add_target(dmt, 0, size, DM_CRYPT_TARGET, params))
 290                 goto out_no_removal;
 291
 292 #ifdef DM_READ_AHEAD_MINIMUM_FLAG
 293         if (_dev_read_ahead(device, &read_ahead) &&
 294             !dm_task_set_read_ahead(dmt, read_ahead, DM_READ_AHEAD_MINIMUM_FLAG))
 295                 goto out_no_removal;
 296 #endif
 297
 298         if (uuid && !dm_task_set_uuid(dmt, dev_uuid))
 299                 goto out_no_removal;
 300
 301         if (!dm_task_run(dmt))
 302                 goto out_no_removal;
 303
 304         if (reload) {
 305                 dm_task_destroy(dmt);
 306                 if (!(dmt = dm_task_create(DM_DEVICE_RESUME)))
 307                         goto out;
 308                 if (!dm_task_set_name(dmt, name))
 309                         goto out;
 310                 if (uuid && !dm_task_set_uuid(dmt, dev_uuid))
 311                         goto out;
 312                 if (!dm_task_run(dmt))
 313                         goto out;
 314         }
 315
 316         if (!dm_task_get_info(dmt, &dmi))
 317                 goto out;
 318
 319         r = 0;
 320 out:
 321         if (r < 0 && !reload) {
 322                 if (get_error())
 323                         error = strdup(get_error());
 324
 325                 dm_remove_device(name, 0, 0);
 326
 327                 if (error) {
 328                         set_error(error);
 329                         free(error);
 330                 }
 331         }
 332
 333 out_no_removal:
 334         if (params)
 335                 safe_free(params);
 336         if (dmt)
 337                 dm_task_destroy(dmt);
 338         if(dmt_query)
 339                 dm_task_destroy(dmt_query);
 340         dm_task_update_nodes();
 341         return r;
 342 }
 343
 344 int dm_status_device(const char *name)
 345 {
 346         struct dm_task *dmt;
 347         struct dm_info dmi;
 348         uint64_t start, length;
 349         char *target_type, *params;
 350         void *next = NULL;
 351         int r = -EINVAL;
 352
 353         if (!(dmt = dm_task_create(DM_DEVICE_STATUS)))
 354                 return -EINVAL;
 355
 356         if (!dm_task_set_name(dmt, name)) {
 357                 r = -EINVAL;
 358                 goto out;
 359         }
 360
 361         if (!dm_task_run(dmt)) {
 362                 r = -ENODEV;
 363                 goto out;
 364         }
 365
 366         if (!dm_task_get_info(dmt, &dmi)) {
 367                 r = -EINVAL;
 368                 goto out;
 369         }
 370
 371         if (!dmi.exists) {
 372                 r = -ENODEV;
 373                 goto out;
 374         }
 375
 376         next = dm_get_next_target(dmt, next, &start, &length,
 377                                   &target_type, &params);
 378         if (!target_type || strcmp(target_type, DM_CRYPT_TARGET) != 0 ||
 379             start != 0 || next)
 380                 r = -EINVAL;
 381         else
 382                 r = (dmi.open_count > 0);
 383 out:
 384         if (dmt)
 385                 dm_task_destroy(dmt);
 386
 387         return r;
 388 }
 389
 390 int dm_query_device(const char *name,
 391                     char **device,
 392                     uint64_t *size,
 393                     uint64_t *skip,
 394                     uint64_t *offset,
 395                     char **cipher,
 396                     int *key_size,
 397                     char **key,
 398                     int *read_only)
 399 {
 400         struct dm_task *dmt;
 401         struct dm_info dmi;
 402         uint64_t start, length, val64;
 403         char *target_type, *params, *rcipher, *key_, *rdevice, *endp, buffer[3];
 404         void *next = NULL;
 405         int i, r = -EINVAL;
 406
 407         if (!(dmt = dm_task_create(DM_DEVICE_TABLE)))
 408                 goto out;
 409         if (!dm_task_set_name(dmt, name))
 410                 goto out;
 411         r = -ENODEV;
 412         if (!dm_task_run(dmt))
 413                 goto out;
 414
 415         r = -EINVAL;
 416         if (!dm_task_get_info(dmt, &dmi))
 417                 goto out;
 418
 419         if (!dmi.exists) {
 420                 r = -ENODEV;
 421                 goto out;
 422         }
 423
 424         next = dm_get_next_target(dmt, next, &start, &length,
 425                                   &target_type, &params);
 426         if (!target_type || strcmp(target_type, DM_CRYPT_TARGET) != 0 ||
 427             start != 0 || next)
 428                 goto out;
 429
 430         if (size)
 431                 *size = length;
 432
 433         rcipher = strsep(&params, " ");
 434         /* cipher */
 435         if (cipher)
 436                 *cipher = strdup(rcipher);
 437
 438         /* skip */
 439         key_ = strsep(&params, " ");
 440         if (!params)
 441                 goto out;
 442         val64 = strtoull(params, &params, 10);
 443         if (*params != ' ')
 444                 goto out;
 445         params++;
 446         if (skip)
 447                 *skip = val64;
 448
 449         /* device */
 450         rdevice = strsep(&params, " ");
 451         if (device)
 452                 *device = lookup_dev(rdevice);
 453
 454         /*offset */
 455         if (!params)
 456                 goto out;
 457         val64 = strtoull(params, &params, 10);
 458         if (*params)
 459                 goto out;
 460         if (offset)
 461                 *offset = val64;
 462
 463         /* key_size */
 464         if (key_size)
 465                 *key_size = strlen(key_) / 2;
 466
 467         /* key */
 468         if (key_size && key) {
 469                 *key = safe_alloc(*key_size);
 470                 if (!*key) {
 471                         r = -ENOMEM;
 472                         goto out;
 473                 }
 474
 475                 buffer[2] = '\0';
 476                 for(i = 0; i < *key_size; i++) {
 477                         memcpy(buffer, &key_[i * 2], 2);
 478                         (*key)[i] = strtoul(buffer, &endp, 16);
 479                         if (endp != &buffer[2]) {
 480                                 safe_free(key);
 481                                 *key = NULL;
 482                                 goto out;
 483                         }
 484                 }
 485         }
 486         memset(key_, 0, strlen(key_));
 487
 488         /* read_only */
 489         if (read_only)
 490                 *read_only = dmi.read_only;
 491
 492         r = (dmi.open_count > 0);
 493 out:
 494         if (dmt)
 495                 dm_task_destroy(dmt);
 496
 497         return r;
 498 }
 499
 500 const char *dm_get_dir(void)
 501 {
 502         return dm_dir();
 503 }