crypto/block-luks.c

   1 /*
   2  * QEMU Crypto block device encryption LUKS format
   3  *
   4  * Copyright (c) 2015-2016 Red Hat, Inc.
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  */
  20
  21 #include "qemu/osdep.h"
  22
  23 #include "crypto/block-luks.h"
  24
  25 #include "crypto/hash.h"
  26 #include "crypto/afsplit.h"
  27 #include "crypto/pbkdf.h"
  28 #include "crypto/secret.h"
  29 #include "crypto/random.h"
  30
  31 #ifdef CONFIG_UUID
  32 #include <uuid/uuid.h>
  33 #endif
  34
  35 #include "qemu/coroutine.h"
  36
  37 /*
  38  * Reference for the LUKS format implemented here is
  39  *
  40  *   docs/on-disk-format.pdf
  41  *
  42  * in 'cryptsetup' package source code
  43  *
  44  * This file implements the 1.2.1 specification, dated
  45  * Oct 16, 2011.
  46  */
  47
  48 typedef struct QCryptoBlockLUKS QCryptoBlockLUKS;
  49 typedef struct QCryptoBlockLUKSHeader QCryptoBlockLUKSHeader;
  50 typedef struct QCryptoBlockLUKSKeySlot QCryptoBlockLUKSKeySlot;
  51
  52
  53 /* The following constants are all defined by the LUKS spec */
  54 #define QCRYPTO_BLOCK_LUKS_VERSION 1
  55
  56 #define QCRYPTO_BLOCK_LUKS_MAGIC_LEN 6
  57 #define QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN 32
  58 #define QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN 32
  59 #define QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN 32
  60 #define QCRYPTO_BLOCK_LUKS_DIGEST_LEN 20
  61 #define QCRYPTO_BLOCK_LUKS_SALT_LEN 32
  62 #define QCRYPTO_BLOCK_LUKS_UUID_LEN 40
  63 #define QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS 8
  64 #define QCRYPTO_BLOCK_LUKS_STRIPES 4000
  65 #define QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS 1000
  66 #define QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS 1000
  67 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET 4096
  68
  69 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED 0x0000DEAD
  70 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED 0x00AC71F3
  71
  72 #define QCRYPTO_BLOCK_LUKS_SECTOR_SIZE 512LL
  73
  74 static const char qcrypto_block_luks_magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN] = {
  75     'L', 'U', 'K', 'S', 0xBA, 0xBE
  76 };
  77
  78 typedef struct QCryptoBlockLUKSNameMap QCryptoBlockLUKSNameMap;
  79 struct QCryptoBlockLUKSNameMap {
  80     const char *name;
  81     int id;
  82 };
  83
  84 typedef struct QCryptoBlockLUKSCipherSizeMap QCryptoBlockLUKSCipherSizeMap;
  85 struct QCryptoBlockLUKSCipherSizeMap {
  86     uint32_t key_bytes;
  87     int id;
  88 };
  89 typedef struct QCryptoBlockLUKSCipherNameMap QCryptoBlockLUKSCipherNameMap;
  90 struct QCryptoBlockLUKSCipherNameMap {
  91     const char *name;
  92     const QCryptoBlockLUKSCipherSizeMap *sizes;
  93 };
  94
  95
  96 static const QCryptoBlockLUKSCipherSizeMap
  97 qcrypto_block_luks_cipher_size_map_aes[] = {
  98     { 16, QCRYPTO_CIPHER_ALG_AES_128 },
  99     { 24, QCRYPTO_CIPHER_ALG_AES_192 },
 100     { 32, QCRYPTO_CIPHER_ALG_AES_256 },
 101     { 0, 0 },
 102 };
 103
 104 static const QCryptoBlockLUKSCipherSizeMap
 105 qcrypto_block_luks_cipher_size_map_cast5[] = {
 106     { 16, QCRYPTO_CIPHER_ALG_CAST5_128 },
 107     { 0, 0 },
 108 };
 109
 110 static const QCryptoBlockLUKSCipherSizeMap
 111 qcrypto_block_luks_cipher_size_map_serpent[] = {
 112     { 16, QCRYPTO_CIPHER_ALG_SERPENT_128 },
 113     { 24, QCRYPTO_CIPHER_ALG_SERPENT_192 },
 114     { 32, QCRYPTO_CIPHER_ALG_SERPENT_256 },
 115     { 0, 0 },
 116 };
 117
 118 static const QCryptoBlockLUKSCipherSizeMap
 119 qcrypto_block_luks_cipher_size_map_twofish[] = {
 120     { 16, QCRYPTO_CIPHER_ALG_TWOFISH_128 },
 121     { 24, QCRYPTO_CIPHER_ALG_TWOFISH_192 },
 122     { 32, QCRYPTO_CIPHER_ALG_TWOFISH_256 },
 123     { 0, 0 },
 124 };
 125
 126 static const QCryptoBlockLUKSCipherNameMap
 127 qcrypto_block_luks_cipher_name_map[] = {
 128     { "aes", qcrypto_block_luks_cipher_size_map_aes },
 129     { "cast5", qcrypto_block_luks_cipher_size_map_cast5 },
 130     { "serpent", qcrypto_block_luks_cipher_size_map_serpent },
 131     { "twofish", qcrypto_block_luks_cipher_size_map_twofish },
 132 };
 133
 134
 135 /*
 136  * This struct is written to disk in big-endian format,
 137  * but operated upon in native-endian format.
 138  */
 139 struct QCryptoBlockLUKSKeySlot {
 140     /* state of keyslot, enabled/disable */
 141     uint32_t active;
 142     /* iterations for PBKDF2 */
 143     uint32_t iterations;
 144     /* salt for PBKDF2 */
 145     uint8_t salt[QCRYPTO_BLOCK_LUKS_SALT_LEN];
 146     /* start sector of key material */
 147     uint32_t key_offset;
 148     /* number of anti-forensic stripes */
 149     uint32_t stripes;
 150 } QEMU_PACKED;
 151
 152 QEMU_BUILD_BUG_ON(sizeof(struct QCryptoBlockLUKSKeySlot) != 48);
 153
 154
 155 /*
 156  * This struct is written to disk in big-endian format,
 157  * but operated upon in native-endian format.
 158  */
 159 struct QCryptoBlockLUKSHeader {
 160     /* 'L', 'U', 'K', 'S', '0xBA', '0xBE' */
 161     char magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN];
 162
 163     /* LUKS version, currently 1 */
 164     uint16_t version;
 165
 166     /* cipher name specification (aes, etc) */
 167     char cipher_name[QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN];
 168
 169     /* cipher mode specification (cbc-plain, xts-essiv:sha256, etc) */
 170     char cipher_mode[QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN];
 171
 172     /* hash specification (sha256, etc) */
 173     char hash_spec[QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN];
 174
 175     /* start offset of the volume data (in 512 byte sectors) */
 176     uint32_t payload_offset;
 177
 178     /* Number of key bytes */
 179     uint32_t key_bytes;
 180
 181     /* master key checksum after PBKDF2 */
 182     uint8_t master_key_digest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN];
 183
 184     /* salt for master key PBKDF2 */
 185     uint8_t master_key_salt[QCRYPTO_BLOCK_LUKS_SALT_LEN];
 186
 187     /* iterations for master key PBKDF2 */
 188     uint32_t master_key_iterations;
 189
 190     /* UUID of the partition in standard ASCII representation */
 191     uint8_t uuid[QCRYPTO_BLOCK_LUKS_UUID_LEN];
 192
 193     /* key slots */
 194     QCryptoBlockLUKSKeySlot key_slots[QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS];
 195 } QEMU_PACKED;
 196
 197 QEMU_BUILD_BUG_ON(sizeof(struct QCryptoBlockLUKSHeader) != 592);
 198
 199
 200 struct QCryptoBlockLUKS {
 201     QCryptoBlockLUKSHeader header;
 202 };
 203
 204
 205 static int qcrypto_block_luks_cipher_name_lookup(const char *name,
 206                                                  QCryptoCipherMode mode,
 207                                                  uint32_t key_bytes,
 208                                                  Error **errp)
 209 {
 210     const QCryptoBlockLUKSCipherNameMap *map =
 211         qcrypto_block_luks_cipher_name_map;
 212     size_t maplen = G_N_ELEMENTS(qcrypto_block_luks_cipher_name_map);
 213     size_t i, j;
 214
 215     if (mode == QCRYPTO_CIPHER_MODE_XTS) {
 216         key_bytes /= 2;
 217     }
 218
 219     for (i = 0; i < maplen; i++) {
 220         if (!g_str_equal(map[i].name, name)) {
 221             continue;
 222         }
 223         for (j = 0; j < map[i].sizes[j].key_bytes; j++) {
 224             if (map[i].sizes[j].key_bytes == key_bytes) {
 225                 return map[i].sizes[j].id;
 226             }
 227         }
 228     }
 229
 230     error_setg(errp, "Algorithm %s with key size %d bytes not supported",
 231                name, key_bytes);
 232     return 0;
 233 }
 234
 235 static const char *
 236 qcrypto_block_luks_cipher_alg_lookup(QCryptoCipherAlgorithm alg,
 237                                      Error **errp)
 238 {
 239     const QCryptoBlockLUKSCipherNameMap *map =
 240         qcrypto_block_luks_cipher_name_map;
 241     size_t maplen = G_N_ELEMENTS(qcrypto_block_luks_cipher_name_map);
 242     size_t i, j;
 243     for (i = 0; i < maplen; i++) {
 244         for (j = 0; j < map[i].sizes[j].key_bytes; j++) {
 245             if (map[i].sizes[j].id == alg) {
 246                 return map[i].name;
 247             }
 248         }
 249     }
 250
 251     error_setg(errp, "Algorithm '%s' not supported",
 252                QCryptoCipherAlgorithm_lookup[alg]);
 253     return NULL;
 254 }
 255
 256 /* XXX replace with qapi_enum_parse() in future, when we can
 257  * make that function emit a more friendly error message */
 258 static int qcrypto_block_luks_name_lookup(const char *name,
 259                                           const char *const *map,
 260                                           size_t maplen,
 261                                           const char *type,
 262                                           Error **errp)
 263 {
 264     size_t i;
 265     for (i = 0; i < maplen; i++) {
 266         if (g_str_equal(map[i], name)) {
 267             return i;
 268         }
 269     }
 270
 271     error_setg(errp, "%s %s not supported", type, name);
 272     return 0;
 273 }
 274
 275 #define qcrypto_block_luks_cipher_mode_lookup(name, errp)               \
 276     qcrypto_block_luks_name_lookup(name,                                \
 277                                    QCryptoCipherMode_lookup,            \
 278                                    QCRYPTO_CIPHER_MODE__MAX,            \
 279                                    "Cipher mode",                       \
 280                                    errp)
 281
 282 #define qcrypto_block_luks_hash_name_lookup(name, errp)                 \
 283     qcrypto_block_luks_name_lookup(name,                                \
 284                                    QCryptoHashAlgorithm_lookup,         \
 285                                    QCRYPTO_HASH_ALG__MAX,               \
 286                                    "Hash algorithm",                    \
 287                                    errp)
 288
 289 #define qcrypto_block_luks_ivgen_name_lookup(name, errp)                \
 290     qcrypto_block_luks_name_lookup(name,                                \
 291                                    QCryptoIVGenAlgorithm_lookup,        \
 292                                    QCRYPTO_IVGEN_ALG__MAX,              \
 293                                    "IV generator",                      \
 294                                    errp)
 295
 296
 297 static bool
 298 qcrypto_block_luks_has_format(const uint8_t *buf,
 299                               size_t buf_size)
 300 {
 301     const QCryptoBlockLUKSHeader *luks_header = (const void *)buf;
 302
 303     if (buf_size >= offsetof(QCryptoBlockLUKSHeader, cipher_name) &&
 304         memcmp(luks_header->magic, qcrypto_block_luks_magic,
 305                QCRYPTO_BLOCK_LUKS_MAGIC_LEN) == 0 &&
 306         be16_to_cpu(luks_header->version) == QCRYPTO_BLOCK_LUKS_VERSION) {
 307         return true;
 308     } else {
 309         return false;
 310     }
 311 }
 312
 313
 314 /**
 315  * Deal with a quirk of dm-crypt usage of ESSIV.
 316  *
 317  * When calculating ESSIV IVs, the cipher length used by ESSIV
 318  * may be different from the cipher length used for the block
 319  * encryption, becauses dm-crypt uses the hash digest length
 320  * as the key size. ie, if you have AES 128 as the block cipher
 321  * and SHA 256 as ESSIV hash, then ESSIV will use AES 256 as
 322  * the cipher since that gets a key length matching the digest
 323  * size, not AES 128 with truncated digest as might be imagined
 324  */
 325 static QCryptoCipherAlgorithm
 326 qcrypto_block_luks_essiv_cipher(QCryptoCipherAlgorithm cipher,
 327                                 QCryptoHashAlgorithm hash,
 328                                 Error **errp)
 329 {
 330     size_t digestlen = qcrypto_hash_digest_len(hash);
 331     size_t keylen = qcrypto_cipher_get_key_len(cipher);
 332     if (digestlen == keylen) {
 333         return cipher;
 334     }
 335
 336     switch (cipher) {
 337     case QCRYPTO_CIPHER_ALG_AES_128:
 338     case QCRYPTO_CIPHER_ALG_AES_192:
 339     case QCRYPTO_CIPHER_ALG_AES_256:
 340         if (digestlen == qcrypto_cipher_get_key_len(
 341                 QCRYPTO_CIPHER_ALG_AES_128)) {
 342             return QCRYPTO_CIPHER_ALG_AES_128;
 343         } else if (digestlen == qcrypto_cipher_get_key_len(
 344                        QCRYPTO_CIPHER_ALG_AES_192)) {
 345             return QCRYPTO_CIPHER_ALG_AES_192;
 346         } else if (digestlen == qcrypto_cipher_get_key_len(
 347                        QCRYPTO_CIPHER_ALG_AES_256)) {
 348             return QCRYPTO_CIPHER_ALG_AES_256;
 349         } else {
 350             error_setg(errp, "No AES cipher with key size %zu available",
 351                        digestlen);
 352             return 0;
 353         }
 354         break;
 355     case QCRYPTO_CIPHER_ALG_SERPENT_128:
 356     case QCRYPTO_CIPHER_ALG_SERPENT_192:
 357     case QCRYPTO_CIPHER_ALG_SERPENT_256:
 358         if (digestlen == qcrypto_cipher_get_key_len(
 359                 QCRYPTO_CIPHER_ALG_SERPENT_128)) {
 360             return QCRYPTO_CIPHER_ALG_SERPENT_128;
 361         } else if (digestlen == qcrypto_cipher_get_key_len(
 362                        QCRYPTO_CIPHER_ALG_SERPENT_192)) {
 363             return QCRYPTO_CIPHER_ALG_SERPENT_192;
 364         } else if (digestlen == qcrypto_cipher_get_key_len(
 365                        QCRYPTO_CIPHER_ALG_SERPENT_256)) {
 366             return QCRYPTO_CIPHER_ALG_SERPENT_256;
 367         } else {
 368             error_setg(errp, "No Serpent cipher with key size %zu available",
 369                        digestlen);
 370             return 0;
 371         }
 372         break;
 373     case QCRYPTO_CIPHER_ALG_TWOFISH_128:
 374     case QCRYPTO_CIPHER_ALG_TWOFISH_192:
 375     case QCRYPTO_CIPHER_ALG_TWOFISH_256:
 376         if (digestlen == qcrypto_cipher_get_key_len(
 377                 QCRYPTO_CIPHER_ALG_TWOFISH_128)) {
 378             return QCRYPTO_CIPHER_ALG_TWOFISH_128;
 379         } else if (digestlen == qcrypto_cipher_get_key_len(
 380                        QCRYPTO_CIPHER_ALG_TWOFISH_192)) {
 381             return QCRYPTO_CIPHER_ALG_TWOFISH_192;
 382         } else if (digestlen == qcrypto_cipher_get_key_len(
 383                        QCRYPTO_CIPHER_ALG_TWOFISH_256)) {
 384             return QCRYPTO_CIPHER_ALG_TWOFISH_256;
 385         } else {
 386             error_setg(errp, "No Twofish cipher with key size %zu available",
 387                        digestlen);
 388             return 0;
 389         }
 390         break;
 391     default:
 392         error_setg(errp, "Cipher %s not supported with essiv",
 393                    QCryptoCipherAlgorithm_lookup[cipher]);
 394         return 0;
 395     }
 396 }
 397
 398 /*
 399  * Given a key slot, and user password, this will attempt to unlock
 400  * the master encryption key from the key slot.
 401  *
 402  * Returns:
 403  *    0 if the key slot is disabled, or key could not be decrypted
 404  *      with the provided password
 405  *    1 if the key slot is enabled, and key decrypted successfully
 406  *      with the provided password
 407  *   -1 if a fatal error occurred loading the key
 408  */
 409 static int
 410 qcrypto_block_luks_load_key(QCryptoBlock *block,
 411                             QCryptoBlockLUKSKeySlot *slot,
 412                             const char *password,
 413                             QCryptoCipherAlgorithm cipheralg,
 414                             QCryptoCipherMode ciphermode,
 415                             QCryptoHashAlgorithm hash,
 416                             QCryptoIVGenAlgorithm ivalg,
 417                             QCryptoCipherAlgorithm ivcipheralg,
 418                             QCryptoHashAlgorithm ivhash,
 419                             uint8_t *masterkey,
 420                             size_t masterkeylen,
 421                             QCryptoBlockReadFunc readfunc,
 422                             void *opaque,
 423                             Error **errp)
 424 {
 425     QCryptoBlockLUKS *luks = block->opaque;
 426     uint8_t *splitkey;
 427     size_t splitkeylen;
 428     uint8_t *possiblekey;
 429     int ret = -1;
 430     ssize_t rv;
 431     QCryptoCipher *cipher = NULL;
 432     uint8_t keydigest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN];
 433     QCryptoIVGen *ivgen = NULL;
 434     size_t niv;
 435
 436     if (slot->active != QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED) {
 437         return 0;
 438     }
 439
 440     splitkeylen = masterkeylen * slot->stripes;
 441     splitkey = g_new0(uint8_t, splitkeylen);
 442     possiblekey = g_new0(uint8_t, masterkeylen);
 443
 444     /*
 445      * The user password is used to generate a (possible)
 446      * decryption key. This may or may not successfully
 447      * decrypt the master key - we just blindly assume
 448      * the key is correct and validate the results of
 449      * decryption later.
 450      */
 451     if (qcrypto_pbkdf2(hash,
 452                        (const uint8_t *)password, strlen(password),
 453                        slot->salt, QCRYPTO_BLOCK_LUKS_SALT_LEN,
 454                        slot->iterations,
 455                        possiblekey, masterkeylen,
 456                        errp) < 0) {
 457         goto cleanup;
 458     }
 459
 460     /*
 461      * We need to read the master key material from the
 462      * LUKS key material header. What we're reading is
 463      * not the raw master key, but rather the data after
 464      * it has been passed through AFSplit and the result
 465      * then encrypted.
 466      */
 467     rv = readfunc(block,
 468                   slot->key_offset * QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
 469                   splitkey, splitkeylen,
 470                   errp,
 471                   opaque);
 472     if (rv < 0) {
 473         goto cleanup;
 474     }
 475
 476
 477     /* Setup the cipher/ivgen that we'll use to try to decrypt
 478      * the split master key material */
 479     cipher = qcrypto_cipher_new(cipheralg, ciphermode,
 480                                 possiblekey, masterkeylen,
 481                                 errp);
 482     if (!cipher) {
 483         goto cleanup;
 484     }
 485
 486     niv = qcrypto_cipher_get_iv_len(cipheralg,
 487                                     ciphermode);
 488     ivgen = qcrypto_ivgen_new(ivalg,
 489                               ivcipheralg,
 490                               ivhash,
 491                               possiblekey, masterkeylen,
 492                               errp);
 493     if (!ivgen) {
 494         goto cleanup;
 495     }
 496
 497
 498     /*
 499      * The master key needs to be decrypted in the same
 500      * way that the block device payload will be decrypted
 501      * later. In particular we'll be using the IV generator
 502      * to reset the encryption cipher every time the master
 503      * key crosses a sector boundary.
 504      */
 505     if (qcrypto_block_decrypt_helper(cipher,
 506                                      niv,
 507                                      ivgen,
 508                                      QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
 509                                      0,
 510                                      splitkey,
 511                                      splitkeylen,
 512                                      errp) < 0) {
 513         goto cleanup;
 514     }
 515
 516     /*
 517      * Now we've decrypted the split master key, join
 518      * it back together to get the actual master key.
 519      */
 520     if (qcrypto_afsplit_decode(hash,
 521                                masterkeylen,
 522                                slot->stripes,
 523                                splitkey,
 524                                masterkey,
 525                                errp) < 0) {
 526         goto cleanup;
 527     }
 528
 529
 530     /*
 531      * We still don't know that the masterkey we got is valid,
 532      * because we just blindly assumed the user's password
 533      * was correct. This is where we now verify it. We are
 534      * creating a hash of the master key using PBKDF and
 535      * then comparing that to the hash stored in the key slot
 536      * header
 537      */
 538     if (qcrypto_pbkdf2(hash,
 539                        masterkey, masterkeylen,
 540                        luks->header.master_key_salt,
 541                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
 542                        luks->header.master_key_iterations,
 543                        keydigest, G_N_ELEMENTS(keydigest),
 544                        errp) < 0) {
 545         goto cleanup;
 546     }
 547
 548     if (memcmp(keydigest, luks->header.master_key_digest,
 549                QCRYPTO_BLOCK_LUKS_DIGEST_LEN) == 0) {
 550         /* Success, we got the right master key */
 551         ret = 1;
 552         goto cleanup;
 553     }
 554
 555     /* Fail, user's password was not valid for this key slot,
 556      * tell caller to try another slot */
 557     ret = 0;
 558
 559  cleanup:
 560     qcrypto_ivgen_free(ivgen);
 561     qcrypto_cipher_free(cipher);
 562     g_free(splitkey);
 563     g_free(possiblekey);
 564     return ret;
 565 }
 566
 567
 568 /*
 569  * Given a user password, this will iterate over all key
 570  * slots and try to unlock each active key slot using the
 571  * password until it successfully obtains a master key.
 572  *
 573  * Returns 0 if a key was loaded, -1 if no keys could be loaded
 574  */
 575 static int
 576 qcrypto_block_luks_find_key(QCryptoBlock *block,
 577                             const char *password,
 578                             QCryptoCipherAlgorithm cipheralg,
 579                             QCryptoCipherMode ciphermode,
 580                             QCryptoHashAlgorithm hash,
 581                             QCryptoIVGenAlgorithm ivalg,
 582                             QCryptoCipherAlgorithm ivcipheralg,
 583                             QCryptoHashAlgorithm ivhash,
 584                             uint8_t **masterkey,
 585                             size_t *masterkeylen,
 586                             QCryptoBlockReadFunc readfunc,
 587                             void *opaque,
 588                             Error **errp)
 589 {
 590     QCryptoBlockLUKS *luks = block->opaque;
 591     size_t i;
 592     int rv;
 593
 594     *masterkey = g_new0(uint8_t, luks->header.key_bytes);
 595     *masterkeylen = luks->header.key_bytes;
 596
 597     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
 598         rv = qcrypto_block_luks_load_key(block,
 599                                          &luks->header.key_slots[i],
 600                                          password,
 601                                          cipheralg,
 602                                          ciphermode,
 603                                          hash,
 604                                          ivalg,
 605                                          ivcipheralg,
 606                                          ivhash,
 607                                          *masterkey,
 608                                          *masterkeylen,
 609                                          readfunc,
 610                                          opaque,
 611                                          errp);
 612         if (rv < 0) {
 613             goto error;
 614         }
 615         if (rv == 1) {
 616             return 0;
 617         }
 618     }
 619
 620     error_setg(errp, "Invalid password, cannot unlock any keyslot");
 621
 622  error:
 623     g_free(*masterkey);
 624     *masterkey = NULL;
 625     *masterkeylen = 0;
 626     return -1;
 627 }
 628
 629
 630 static int
 631 qcrypto_block_luks_open(QCryptoBlock *block,
 632                         QCryptoBlockOpenOptions *options,
 633                         QCryptoBlockReadFunc readfunc,
 634                         void *opaque,
 635                         unsigned int flags,
 636                         Error **errp)
 637 {
 638     QCryptoBlockLUKS *luks;
 639     Error *local_err = NULL;
 640     int ret = 0;
 641     size_t i;
 642     ssize_t rv;
 643     uint8_t *masterkey = NULL;
 644     size_t masterkeylen;
 645     char *ivgen_name, *ivhash_name;
 646     QCryptoCipherMode ciphermode;
 647     QCryptoCipherAlgorithm cipheralg;
 648     QCryptoIVGenAlgorithm ivalg;
 649     QCryptoCipherAlgorithm ivcipheralg;
 650     QCryptoHashAlgorithm hash;
 651     QCryptoHashAlgorithm ivhash;
 652     char *password = NULL;
 653
 654     if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) {
 655         if (!options->u.luks.key_secret) {
 656             error_setg(errp, "Parameter 'key-secret' is required for cipher");
 657             return -1;
 658         }
 659         password = qcrypto_secret_lookup_as_utf8(
 660             options->u.luks.key_secret, errp);
 661         if (!password) {
 662             return -1;
 663         }
 664     }
 665
 666     luks = g_new0(QCryptoBlockLUKS, 1);
 667     block->opaque = luks;
 668
 669     /* Read the entire LUKS header, minus the key material from
 670      * the underlying device */
 671     rv = readfunc(block, 0,
 672                   (uint8_t *)&luks->header,
 673                   sizeof(luks->header),
 674                   errp,
 675                   opaque);
 676     if (rv < 0) {
 677         ret = rv;
 678         goto fail;
 679     }
 680
 681     /* The header is always stored in big-endian format, so
 682      * convert everything to native */
 683     be16_to_cpus(&luks->header.version);
 684     be32_to_cpus(&luks->header.payload_offset);
 685     be32_to_cpus(&luks->header.key_bytes);
 686     be32_to_cpus(&luks->header.master_key_iterations);
 687
 688     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
 689         be32_to_cpus(&luks->header.key_slots[i].active);
 690         be32_to_cpus(&luks->header.key_slots[i].iterations);
 691         be32_to_cpus(&luks->header.key_slots[i].key_offset);
 692         be32_to_cpus(&luks->header.key_slots[i].stripes);
 693     }
 694
 695     if (memcmp(luks->header.magic, qcrypto_block_luks_magic,
 696                QCRYPTO_BLOCK_LUKS_MAGIC_LEN) != 0) {
 697         error_setg(errp, "Volume is not in LUKS format");
 698         ret = -EINVAL;
 699         goto fail;
 700     }
 701     if (luks->header.version != QCRYPTO_BLOCK_LUKS_VERSION) {
 702         error_setg(errp, "LUKS version %" PRIu32 " is not supported",
 703                    luks->header.version);
 704         ret = -ENOTSUP;
 705         goto fail;
 706     }
 707
 708     /*
 709      * The cipher_mode header contains a string that we have
 710      * to further parse, of the format
 711      *
 712      *    <cipher-mode>-<iv-generator>[:<iv-hash>]
 713      *
 714      * eg  cbc-essiv:sha256, cbc-plain64
 715      */
 716     ivgen_name = strchr(luks->header.cipher_mode, '-');
 717     if (!ivgen_name) {
 718         ret = -EINVAL;
 719         error_setg(errp, "Unexpected cipher mode string format %s",
 720                    luks->header.cipher_mode);
 721         goto fail;
 722     }
 723     *ivgen_name = '\0';
 724     ivgen_name++;
 725
 726     ivhash_name = strchr(ivgen_name, ':');
 727     if (!ivhash_name) {
 728         ivhash = 0;
 729     } else {
 730         *ivhash_name = '\0';
 731         ivhash_name++;
 732
 733         ivhash = qcrypto_block_luks_hash_name_lookup(ivhash_name,
 734                                                      &local_err);
 735         if (local_err) {
 736             ret = -ENOTSUP;
 737             error_propagate(errp, local_err);
 738             goto fail;
 739         }
 740     }
 741
 742     ciphermode = qcrypto_block_luks_cipher_mode_lookup(luks->header.cipher_mode,
 743                                                        &local_err);
 744     if (local_err) {
 745         ret = -ENOTSUP;
 746         error_propagate(errp, local_err);
 747         goto fail;
 748     }
 749
 750     cipheralg = qcrypto_block_luks_cipher_name_lookup(luks->header.cipher_name,
 751                                                       ciphermode,
 752                                                       luks->header.key_bytes,
 753                                                       &local_err);
 754     if (local_err) {
 755         ret = -ENOTSUP;
 756         error_propagate(errp, local_err);
 757         goto fail;
 758     }
 759
 760     hash = qcrypto_block_luks_hash_name_lookup(luks->header.hash_spec,
 761                                                &local_err);
 762     if (local_err) {
 763         ret = -ENOTSUP;
 764         error_propagate(errp, local_err);
 765         goto fail;
 766     }
 767
 768     ivalg = qcrypto_block_luks_ivgen_name_lookup(ivgen_name,
 769                                                  &local_err);
 770     if (local_err) {
 771         ret = -ENOTSUP;
 772         error_propagate(errp, local_err);
 773         goto fail;
 774     }
 775
 776     if (ivalg == QCRYPTO_IVGEN_ALG_ESSIV) {
 777         ivcipheralg = qcrypto_block_luks_essiv_cipher(cipheralg,
 778                                                       ivhash,
 779                                                       &local_err);
 780         if (local_err) {
 781             ret = -ENOTSUP;
 782             error_propagate(errp, local_err);
 783             goto fail;
 784         }
 785     } else {
 786         ivcipheralg = cipheralg;
 787     }
 788
 789     if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) {
 790         /* Try to find which key slot our password is valid for
 791          * and unlock the master key from that slot.
 792          */
 793         if (qcrypto_block_luks_find_key(block,
 794                                         password,
 795                                         cipheralg, ciphermode,
 796                                         hash,
 797                                         ivalg,
 798                                         ivcipheralg,
 799                                         ivhash,
 800                                         &masterkey, &masterkeylen,
 801                                         readfunc, opaque,
 802                                         errp) < 0) {
 803             ret = -EACCES;
 804             goto fail;
 805         }
 806
 807         /* We have a valid master key now, so can setup the
 808          * block device payload decryption objects
 809          */
 810         block->kdfhash = hash;
 811         block->niv = qcrypto_cipher_get_iv_len(cipheralg,
 812                                                ciphermode);
 813         block->ivgen = qcrypto_ivgen_new(ivalg,
 814                                          ivcipheralg,
 815                                          ivhash,
 816                                          masterkey, masterkeylen,
 817                                          errp);
 818         if (!block->ivgen) {
 819             ret = -ENOTSUP;
 820             goto fail;
 821         }
 822
 823         block->cipher = qcrypto_cipher_new(cipheralg,
 824                                            ciphermode,
 825                                            masterkey, masterkeylen,
 826                                            errp);
 827         if (!block->cipher) {
 828             ret = -ENOTSUP;
 829             goto fail;
 830         }
 831     }
 832
 833     block->payload_offset = luks->header.payload_offset *
 834         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
 835
 836     g_free(masterkey);
 837     g_free(password);
 838
 839     return 0;
 840
 841  fail:
 842     g_free(masterkey);
 843     qcrypto_cipher_free(block->cipher);
 844     qcrypto_ivgen_free(block->ivgen);
 845     g_free(luks);
 846     g_free(password);
 847     return ret;
 848 }
 849
 850
 851 static int
 852 qcrypto_block_luks_uuid_gen(uint8_t *uuidstr, Error **errp)
 853 {
 854 #ifdef CONFIG_UUID
 855     uuid_t uuid;
 856     uuid_generate(uuid);
 857     uuid_unparse(uuid, (char *)uuidstr);
 858     return 0;
 859 #else
 860     error_setg(errp, "Unable to generate uuids on this platform");
 861     return -1;
 862 #endif
 863 }
 864
 865 static int
 866 qcrypto_block_luks_create(QCryptoBlock *block,
 867                           QCryptoBlockCreateOptions *options,
 868                           QCryptoBlockInitFunc initfunc,
 869                           QCryptoBlockWriteFunc writefunc,
 870                           void *opaque,
 871                           Error **errp)
 872 {
 873     QCryptoBlockLUKS *luks;
 874     QCryptoBlockCreateOptionsLUKS luks_opts;
 875     Error *local_err = NULL;
 876     uint8_t *masterkey = NULL;
 877     uint8_t *slotkey = NULL;
 878     uint8_t *splitkey = NULL;
 879     size_t splitkeylen = 0;
 880     size_t i;
 881     QCryptoCipher *cipher = NULL;
 882     QCryptoIVGen *ivgen = NULL;
 883     char *password;
 884     const char *cipher_alg;
 885     const char *cipher_mode;
 886     const char *ivgen_alg;
 887     const char *ivgen_hash_alg = NULL;
 888     const char *hash_alg;
 889     char *cipher_mode_spec = NULL;
 890     QCryptoCipherAlgorithm ivcipheralg = 0;
 891
 892     memcpy(&luks_opts, &options->u.luks, sizeof(luks_opts));
 893     if (!luks_opts.has_cipher_alg) {
 894         luks_opts.cipher_alg = QCRYPTO_CIPHER_ALG_AES_256;
 895     }
 896     if (!luks_opts.has_cipher_mode) {
 897         luks_opts.cipher_mode = QCRYPTO_CIPHER_MODE_XTS;
 898     }
 899     if (!luks_opts.has_ivgen_alg) {
 900         luks_opts.ivgen_alg = QCRYPTO_IVGEN_ALG_PLAIN64;
 901     }
 902     if (!luks_opts.has_hash_alg) {
 903         luks_opts.hash_alg = QCRYPTO_HASH_ALG_SHA256;
 904     }
 905
 906     if (!options->u.luks.key_secret) {
 907         error_setg(errp, "Parameter 'key-secret' is required for cipher");
 908         return -1;
 909     }
 910     password = qcrypto_secret_lookup_as_utf8(luks_opts.key_secret, errp);
 911     if (!password) {
 912         return -1;
 913     }
 914
 915     luks = g_new0(QCryptoBlockLUKS, 1);
 916     block->opaque = luks;
 917
 918     memcpy(luks->header.magic, qcrypto_block_luks_magic,
 919            QCRYPTO_BLOCK_LUKS_MAGIC_LEN);
 920
 921     /* We populate the header in native endianness initially and
 922      * then convert everything to big endian just before writing
 923      * it out to disk
 924      */
 925     luks->header.version = QCRYPTO_BLOCK_LUKS_VERSION;
 926     if (qcrypto_block_luks_uuid_gen(luks->header.uuid,
 927                                     errp) < 0) {
 928         goto error;
 929     }
 930
 931     cipher_alg = qcrypto_block_luks_cipher_alg_lookup(luks_opts.cipher_alg,
 932                                                       errp);
 933     if (!cipher_alg) {
 934         goto error;
 935     }
 936
 937     cipher_mode = QCryptoCipherMode_lookup[luks_opts.cipher_mode];
 938     ivgen_alg = QCryptoIVGenAlgorithm_lookup[luks_opts.ivgen_alg];
 939     if (luks_opts.has_ivgen_hash_alg) {
 940         ivgen_hash_alg = QCryptoHashAlgorithm_lookup[luks_opts.ivgen_hash_alg];
 941         cipher_mode_spec = g_strdup_printf("%s-%s:%s", cipher_mode, ivgen_alg,
 942                                            ivgen_hash_alg);
 943     } else {
 944         cipher_mode_spec = g_strdup_printf("%s-%s", cipher_mode, ivgen_alg);
 945     }
 946     hash_alg = QCryptoHashAlgorithm_lookup[luks_opts.hash_alg];
 947
 948
 949     if (strlen(cipher_alg) >= QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN) {
 950         error_setg(errp, "Cipher name '%s' is too long for LUKS header",
 951                    cipher_alg);
 952         goto error;
 953     }
 954     if (strlen(cipher_mode_spec) >= QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN) {
 955         error_setg(errp, "Cipher mode '%s' is too long for LUKS header",
 956                    cipher_mode_spec);
 957         goto error;
 958     }
 959     if (strlen(hash_alg) >= QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN) {
 960         error_setg(errp, "Hash name '%s' is too long for LUKS header",
 961                    hash_alg);
 962         goto error;
 963     }
 964
 965     if (luks_opts.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
 966         ivcipheralg = qcrypto_block_luks_essiv_cipher(luks_opts.cipher_alg,
 967                                                       luks_opts.ivgen_hash_alg,
 968                                                       &local_err);
 969         if (local_err) {
 970             error_propagate(errp, local_err);
 971             goto error;
 972         }
 973     } else {
 974         ivcipheralg = luks_opts.cipher_alg;
 975     }
 976
 977     strcpy(luks->header.cipher_name, cipher_alg);
 978     strcpy(luks->header.cipher_mode, cipher_mode_spec);
 979     strcpy(luks->header.hash_spec, hash_alg);
 980
 981     luks->header.key_bytes = qcrypto_cipher_get_key_len(luks_opts.cipher_alg);
 982     if (luks_opts.cipher_mode == QCRYPTO_CIPHER_MODE_XTS) {
 983         luks->header.key_bytes *= 2;
 984     }
 985
 986     /* Generate the salt used for hashing the master key
 987      * with PBKDF later
 988      */
 989     if (qcrypto_random_bytes(luks->header.master_key_salt,
 990                              QCRYPTO_BLOCK_LUKS_SALT_LEN,
 991                              errp) < 0) {
 992         goto error;
 993     }
 994
 995     /* Generate random master key */
 996     masterkey = g_new0(uint8_t, luks->header.key_bytes);
 997     if (qcrypto_random_bytes(masterkey,
 998                              luks->header.key_bytes, errp) < 0) {
 999         goto error;
1000     }
1001
1002
1003     /* Setup the block device payload encryption objects */
1004     block->cipher = qcrypto_cipher_new(luks_opts.cipher_alg,
1005                                        luks_opts.cipher_mode,
1006                                        masterkey, luks->header.key_bytes,
1007                                        errp);
1008     if (!block->cipher) {
1009         goto error;
1010     }
1011
1012     block->kdfhash = luks_opts.hash_alg;
1013     block->niv = qcrypto_cipher_get_iv_len(luks_opts.cipher_alg,
1014                                            luks_opts.cipher_mode);
1015     block->ivgen = qcrypto_ivgen_new(luks_opts.ivgen_alg,
1016                                      ivcipheralg,
1017                                      luks_opts.ivgen_hash_alg,
1018                                      masterkey, luks->header.key_bytes,
1019                                      errp);
1020
1021     if (!block->ivgen) {
1022         goto error;
1023     }
1024
1025
1026     /* Determine how many iterations we need to hash the master
1027      * key, in order to have 1 second of compute time used
1028      */
1029     luks->header.master_key_iterations =
1030         qcrypto_pbkdf2_count_iters(luks_opts.hash_alg,
1031                                    masterkey, luks->header.key_bytes,
1032                                    luks->header.master_key_salt,
1033                                    QCRYPTO_BLOCK_LUKS_SALT_LEN,
1034                                    &local_err);
1035     if (local_err) {
1036         error_propagate(errp, local_err);
1037         goto error;
1038     }
1039
1040     /* Why /= 8 ?  That matches cryptsetup, but there's no
1041      * explanation why they chose /= 8... Probably so that
1042      * if all 8 keyslots are active we only spend 1 second
1043      * in total time to check all keys */
1044     luks->header.master_key_iterations /= 8;
1045     luks->header.master_key_iterations = MAX(
1046         luks->header.master_key_iterations,
1047         QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS);
1048
1049
1050     /* Hash the master key, saving the result in the LUKS
1051      * header. This hash is used when opening the encrypted
1052      * device to verify that the user password unlocked a
1053      * valid master key
1054      */
1055     if (qcrypto_pbkdf2(luks_opts.hash_alg,
1056                        masterkey, luks->header.key_bytes,
1057                        luks->header.master_key_salt,
1058                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1059                        luks->header.master_key_iterations,
1060                        luks->header.master_key_digest,
1061                        QCRYPTO_BLOCK_LUKS_DIGEST_LEN,
1062                        errp) < 0) {
1063         goto error;
1064     }
1065
1066
1067     /* Although LUKS has multiple key slots, we're just going
1068      * to use the first key slot */
1069     splitkeylen = luks->header.key_bytes * QCRYPTO_BLOCK_LUKS_STRIPES;
1070     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1071         luks->header.key_slots[i].active = i == 0 ?
1072             QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED :
1073             QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED;
1074         luks->header.key_slots[i].stripes = QCRYPTO_BLOCK_LUKS_STRIPES;
1075
1076         /* This calculation doesn't match that shown in the spec,
1077          * but instead follows the cryptsetup implementation.
1078          */
1079         luks->header.key_slots[i].key_offset =
1080             (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1081              QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) +
1082             (ROUND_UP(((splitkeylen + (QCRYPTO_BLOCK_LUKS_SECTOR_SIZE - 1)) /
1083                        QCRYPTO_BLOCK_LUKS_SECTOR_SIZE),
1084                       (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1085                        QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) * i);
1086     }
1087
1088     if (qcrypto_random_bytes(luks->header.key_slots[0].salt,
1089                              QCRYPTO_BLOCK_LUKS_SALT_LEN,
1090                              errp) < 0) {
1091         goto error;
1092     }
1093
1094     /* Again we determine how many iterations are required to
1095      * hash the user password while consuming 1 second of compute
1096      * time */
1097     luks->header.key_slots[0].iterations =
1098         qcrypto_pbkdf2_count_iters(luks_opts.hash_alg,
1099                                    (uint8_t *)password, strlen(password),
1100                                    luks->header.key_slots[0].salt,
1101                                    QCRYPTO_BLOCK_LUKS_SALT_LEN,
1102                                    &local_err);
1103     if (local_err) {
1104         error_propagate(errp, local_err);
1105         goto error;
1106     }
1107     /* Why /= 2 ?  That matches cryptsetup, but there's no
1108      * explanation why they chose /= 2... */
1109     luks->header.key_slots[0].iterations /= 2;
1110     luks->header.key_slots[0].iterations = MAX(
1111         luks->header.key_slots[0].iterations,
1112         QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS);
1113
1114
1115     /* Generate a key that we'll use to encrypt the master
1116      * key, from the user's password
1117      */
1118     slotkey = g_new0(uint8_t, luks->header.key_bytes);
1119     if (qcrypto_pbkdf2(luks_opts.hash_alg,
1120                        (uint8_t *)password, strlen(password),
1121                        luks->header.key_slots[0].salt,
1122                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1123                        luks->header.key_slots[0].iterations,
1124                        slotkey, luks->header.key_bytes,
1125                        errp) < 0) {
1126         goto error;
1127     }
1128
1129
1130     /* Setup the encryption objects needed to encrypt the
1131      * master key material
1132      */
1133     cipher = qcrypto_cipher_new(luks_opts.cipher_alg,
1134                                 luks_opts.cipher_mode,
1135                                 slotkey, luks->header.key_bytes,
1136                                 errp);
1137     if (!cipher) {
1138         goto error;
1139     }
1140
1141     ivgen = qcrypto_ivgen_new(luks_opts.ivgen_alg,
1142                               ivcipheralg,
1143                               luks_opts.ivgen_hash_alg,
1144                               slotkey, luks->header.key_bytes,
1145                               errp);
1146     if (!ivgen) {
1147         goto error;
1148     }
1149
1150     /* Before storing the master key, we need to vastly
1151      * increase its size, as protection against forensic
1152      * disk data recovery */
1153     splitkey = g_new0(uint8_t, splitkeylen);
1154
1155     if (qcrypto_afsplit_encode(luks_opts.hash_alg,
1156                                luks->header.key_bytes,
1157                                luks->header.key_slots[0].stripes,
1158                                masterkey,
1159                                splitkey,
1160                                errp) < 0) {
1161         goto error;
1162     }
1163
1164     /* Now we encrypt the split master key with the key generated
1165      * from the user's password, before storing it */
1166     if (qcrypto_block_encrypt_helper(cipher, block->niv, ivgen,
1167                                      QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1168                                      0,
1169                                      splitkey,
1170                                      splitkeylen,
1171                                      errp) < 0) {
1172         goto error;
1173     }
1174
1175
1176     /* The total size of the LUKS headers is the partition header + key
1177      * slot headers, rounded up to the nearest sector, combined with
1178      * the size of each master key material region, also rounded up
1179      * to the nearest sector */
1180     luks->header.payload_offset =
1181         (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1182          QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) +
1183         (ROUND_UP(((splitkeylen + (QCRYPTO_BLOCK_LUKS_SECTOR_SIZE - 1)) /
1184                    QCRYPTO_BLOCK_LUKS_SECTOR_SIZE),
1185                   (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1186                    QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) *
1187          QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS);
1188
1189     block->payload_offset = luks->header.payload_offset *
1190         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
1191
1192     /* Reserve header space to match payload offset */
1193     initfunc(block, block->payload_offset, &local_err, opaque);
1194     if (local_err) {
1195         error_propagate(errp, local_err);
1196         goto error;
1197     }
1198
1199     /* Everything on disk uses Big Endian, so flip header fields
1200      * before writing them */
1201     cpu_to_be16s(&luks->header.version);
1202     cpu_to_be32s(&luks->header.payload_offset);
1203     cpu_to_be32s(&luks->header.key_bytes);
1204     cpu_to_be32s(&luks->header.master_key_iterations);
1205
1206     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1207         cpu_to_be32s(&luks->header.key_slots[i].active);
1208         cpu_to_be32s(&luks->header.key_slots[i].iterations);
1209         cpu_to_be32s(&luks->header.key_slots[i].key_offset);
1210         cpu_to_be32s(&luks->header.key_slots[i].stripes);
1211     }
1212
1213
1214     /* Write out the partition header and key slot headers */
1215     writefunc(block, 0,
1216               (const uint8_t *)&luks->header,
1217               sizeof(luks->header),
1218               &local_err,
1219               opaque);
1220
1221     /* Delay checking local_err until we've byte-swapped */
1222
1223     /* Byte swap the header back to native, in case we need
1224      * to read it again later */
1225     be16_to_cpus(&luks->header.version);
1226     be32_to_cpus(&luks->header.payload_offset);
1227     be32_to_cpus(&luks->header.key_bytes);
1228     be32_to_cpus(&luks->header.master_key_iterations);
1229
1230     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1231         be32_to_cpus(&luks->header.key_slots[i].active);
1232         be32_to_cpus(&luks->header.key_slots[i].iterations);
1233         be32_to_cpus(&luks->header.key_slots[i].key_offset);
1234         be32_to_cpus(&luks->header.key_slots[i].stripes);
1235     }
1236
1237     if (local_err) {
1238         error_propagate(errp, local_err);
1239         goto error;
1240     }
1241
1242     /* Write out the master key material, starting at the
1243      * sector immediately following the partition header. */
1244     if (writefunc(block,
1245                   luks->header.key_slots[0].key_offset *
1246                   QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1247                   splitkey, splitkeylen,
1248                   errp,
1249                   opaque) != splitkeylen) {
1250         goto error;
1251     }
1252
1253     memset(masterkey, 0, luks->header.key_bytes);
1254     g_free(masterkey);
1255     memset(slotkey, 0, luks->header.key_bytes);
1256     g_free(slotkey);
1257     g_free(splitkey);
1258     g_free(password);
1259     g_free(cipher_mode_spec);
1260
1261     qcrypto_ivgen_free(ivgen);
1262     qcrypto_cipher_free(cipher);
1263
1264     return 0;
1265
1266  error:
1267     if (masterkey) {
1268         memset(masterkey, 0, luks->header.key_bytes);
1269     }
1270     g_free(masterkey);
1271     if (slotkey) {
1272         memset(slotkey, 0, luks->header.key_bytes);
1273     }
1274     g_free(slotkey);
1275     g_free(splitkey);
1276     g_free(password);
1277     g_free(cipher_mode_spec);
1278
1279     qcrypto_ivgen_free(ivgen);
1280     qcrypto_cipher_free(cipher);
1281
1282     g_free(luks);
1283     return -1;
1284 }
1285
1286
1287 static void qcrypto_block_luks_cleanup(QCryptoBlock *block)
1288 {
1289     g_free(block->opaque);
1290 }
1291
1292
1293 static int
1294 qcrypto_block_luks_decrypt(QCryptoBlock *block,
1295                            uint64_t startsector,
1296                            uint8_t *buf,
1297                            size_t len,
1298                            Error **errp)
1299 {
1300     return qcrypto_block_decrypt_helper(block->cipher,
1301                                         block->niv, block->ivgen,
1302                                         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1303                                         startsector, buf, len, errp);
1304 }
1305
1306
1307 static int
1308 qcrypto_block_luks_encrypt(QCryptoBlock *block,
1309                            uint64_t startsector,
1310                            uint8_t *buf,
1311                            size_t len,
1312                            Error **errp)
1313 {
1314     return qcrypto_block_encrypt_helper(block->cipher,
1315                                         block->niv, block->ivgen,
1316                                         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1317                                         startsector, buf, len, errp);
1318 }
1319
1320
1321 const QCryptoBlockDriver qcrypto_block_driver_luks = {
1322     .open = qcrypto_block_luks_open,
1323     .create = qcrypto_block_luks_create,
1324     .cleanup = qcrypto_block_luks_cleanup,
1325     .decrypt = qcrypto_block_luks_decrypt,
1326     .encrypt = qcrypto_block_luks_encrypt,
1327     .has_format = qcrypto_block_luks_has_format,
1328 };