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 #include "qapi/error.h"
  23 #include "qemu/bswap.h"
  24
  25 #include "crypto/block-luks.h"
  26
  27 #include "crypto/hash.h"
  28 #include "crypto/afsplit.h"
  29 #include "crypto/pbkdf.h"
  30 #include "crypto/secret.h"
  31 #include "crypto/random.h"
  32
  33 #ifdef CONFIG_UUID
  34 #include <uuid/uuid.h>
  35 #endif
  36
  37 #include "qemu/coroutine.h"
  38
  39 /*
  40  * Reference for the LUKS format implemented here is
  41  *
  42  *   docs/on-disk-format.pdf
  43  *
  44  * in 'cryptsetup' package source code
  45  *
  46  * This file implements the 1.2.1 specification, dated
  47  * Oct 16, 2011.
  48  */
  49
  50 typedef struct QCryptoBlockLUKS QCryptoBlockLUKS;
  51 typedef struct QCryptoBlockLUKSHeader QCryptoBlockLUKSHeader;
  52 typedef struct QCryptoBlockLUKSKeySlot QCryptoBlockLUKSKeySlot;
  53
  54
  55 /* The following constants are all defined by the LUKS spec */
  56 #define QCRYPTO_BLOCK_LUKS_VERSION 1
  57
  58 #define QCRYPTO_BLOCK_LUKS_MAGIC_LEN 6
  59 #define QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN 32
  60 #define QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN 32
  61 #define QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN 32
  62 #define QCRYPTO_BLOCK_LUKS_DIGEST_LEN 20
  63 #define QCRYPTO_BLOCK_LUKS_SALT_LEN 32
  64 #define QCRYPTO_BLOCK_LUKS_UUID_LEN 40
  65 #define QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS 8
  66 #define QCRYPTO_BLOCK_LUKS_STRIPES 4000
  67 #define QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS 1000
  68 #define QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS 1000
  69 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET 4096
  70
  71 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED 0x0000DEAD
  72 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED 0x00AC71F3
  73
  74 #define QCRYPTO_BLOCK_LUKS_SECTOR_SIZE 512LL
  75
  76 static const char qcrypto_block_luks_magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN] = {
  77     'L', 'U', 'K', 'S', 0xBA, 0xBE
  78 };
  79
  80 typedef struct QCryptoBlockLUKSNameMap QCryptoBlockLUKSNameMap;
  81 struct QCryptoBlockLUKSNameMap {
  82     const char *name;
  83     int id;
  84 };
  85
  86 typedef struct QCryptoBlockLUKSCipherSizeMap QCryptoBlockLUKSCipherSizeMap;
  87 struct QCryptoBlockLUKSCipherSizeMap {
  88     uint32_t key_bytes;
  89     int id;
  90 };
  91 typedef struct QCryptoBlockLUKSCipherNameMap QCryptoBlockLUKSCipherNameMap;
  92 struct QCryptoBlockLUKSCipherNameMap {
  93     const char *name;
  94     const QCryptoBlockLUKSCipherSizeMap *sizes;
  95 };
  96
  97
  98 static const QCryptoBlockLUKSCipherSizeMap
  99 qcrypto_block_luks_cipher_size_map_aes[] = {
 100     { 16, QCRYPTO_CIPHER_ALG_AES_128 },
 101     { 24, QCRYPTO_CIPHER_ALG_AES_192 },
 102     { 32, QCRYPTO_CIPHER_ALG_AES_256 },
 103     { 0, 0 },
 104 };
 105
 106 static const QCryptoBlockLUKSCipherSizeMap
 107 qcrypto_block_luks_cipher_size_map_cast5[] = {
 108     { 16, QCRYPTO_CIPHER_ALG_CAST5_128 },
 109     { 0, 0 },
 110 };
 111
 112 static const QCryptoBlockLUKSCipherSizeMap
 113 qcrypto_block_luks_cipher_size_map_serpent[] = {
 114     { 16, QCRYPTO_CIPHER_ALG_SERPENT_128 },
 115     { 24, QCRYPTO_CIPHER_ALG_SERPENT_192 },
 116     { 32, QCRYPTO_CIPHER_ALG_SERPENT_256 },
 117     { 0, 0 },
 118 };
 119
 120 static const QCryptoBlockLUKSCipherSizeMap
 121 qcrypto_block_luks_cipher_size_map_twofish[] = {
 122     { 16, QCRYPTO_CIPHER_ALG_TWOFISH_128 },
 123     { 24, QCRYPTO_CIPHER_ALG_TWOFISH_192 },
 124     { 32, QCRYPTO_CIPHER_ALG_TWOFISH_256 },
 125     { 0, 0 },
 126 };
 127
 128 static const QCryptoBlockLUKSCipherNameMap
 129 qcrypto_block_luks_cipher_name_map[] = {
 130     { "aes", qcrypto_block_luks_cipher_size_map_aes },
 131     { "cast5", qcrypto_block_luks_cipher_size_map_cast5 },
 132     { "serpent", qcrypto_block_luks_cipher_size_map_serpent },
 133     { "twofish", qcrypto_block_luks_cipher_size_map_twofish },
 134 };
 135
 136
 137 /*
 138  * This struct is written to disk in big-endian format,
 139  * but operated upon in native-endian format.
 140  */
 141 struct QCryptoBlockLUKSKeySlot {
 142     /* state of keyslot, enabled/disable */
 143     uint32_t active;
 144     /* iterations for PBKDF2 */
 145     uint32_t iterations;
 146     /* salt for PBKDF2 */
 147     uint8_t salt[QCRYPTO_BLOCK_LUKS_SALT_LEN];
 148     /* start sector of key material */
 149     uint32_t key_offset;
 150     /* number of anti-forensic stripes */
 151     uint32_t stripes;
 152 } QEMU_PACKED;
 153
 154 QEMU_BUILD_BUG_ON(sizeof(struct QCryptoBlockLUKSKeySlot) != 48);
 155
 156
 157 /*
 158  * This struct is written to disk in big-endian format,
 159  * but operated upon in native-endian format.
 160  */
 161 struct QCryptoBlockLUKSHeader {
 162     /* 'L', 'U', 'K', 'S', '0xBA', '0xBE' */
 163     char magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN];
 164
 165     /* LUKS version, currently 1 */
 166     uint16_t version;
 167
 168     /* cipher name specification (aes, etc) */
 169     char cipher_name[QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN];
 170
 171     /* cipher mode specification (cbc-plain, xts-essiv:sha256, etc) */
 172     char cipher_mode[QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN];
 173
 174     /* hash specification (sha256, etc) */
 175     char hash_spec[QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN];
 176
 177     /* start offset of the volume data (in 512 byte sectors) */
 178     uint32_t payload_offset;
 179
 180     /* Number of key bytes */
 181     uint32_t key_bytes;
 182
 183     /* master key checksum after PBKDF2 */
 184     uint8_t master_key_digest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN];
 185
 186     /* salt for master key PBKDF2 */
 187     uint8_t master_key_salt[QCRYPTO_BLOCK_LUKS_SALT_LEN];
 188
 189     /* iterations for master key PBKDF2 */
 190     uint32_t master_key_iterations;
 191
 192     /* UUID of the partition in standard ASCII representation */
 193     uint8_t uuid[QCRYPTO_BLOCK_LUKS_UUID_LEN];
 194
 195     /* key slots */
 196     QCryptoBlockLUKSKeySlot key_slots[QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS];
 197 } QEMU_PACKED;
 198
 199 QEMU_BUILD_BUG_ON(sizeof(struct QCryptoBlockLUKSHeader) != 592);
 200
 201
 202 struct QCryptoBlockLUKS {
 203     QCryptoBlockLUKSHeader header;
 204 };
 205
 206
 207 static int qcrypto_block_luks_cipher_name_lookup(const char *name,
 208                                                  QCryptoCipherMode mode,
 209                                                  uint32_t key_bytes,
 210                                                  Error **errp)
 211 {
 212     const QCryptoBlockLUKSCipherNameMap *map =
 213         qcrypto_block_luks_cipher_name_map;
 214     size_t maplen = G_N_ELEMENTS(qcrypto_block_luks_cipher_name_map);
 215     size_t i, j;
 216
 217     if (mode == QCRYPTO_CIPHER_MODE_XTS) {
 218         key_bytes /= 2;
 219     }
 220
 221     for (i = 0; i < maplen; i++) {
 222         if (!g_str_equal(map[i].name, name)) {
 223             continue;
 224         }
 225         for (j = 0; j < map[i].sizes[j].key_bytes; j++) {
 226             if (map[i].sizes[j].key_bytes == key_bytes) {
 227                 return map[i].sizes[j].id;
 228             }
 229         }
 230     }
 231
 232     error_setg(errp, "Algorithm %s with key size %d bytes not supported",
 233                name, key_bytes);
 234     return 0;
 235 }
 236
 237 static const char *
 238 qcrypto_block_luks_cipher_alg_lookup(QCryptoCipherAlgorithm alg,
 239                                      Error **errp)
 240 {
 241     const QCryptoBlockLUKSCipherNameMap *map =
 242         qcrypto_block_luks_cipher_name_map;
 243     size_t maplen = G_N_ELEMENTS(qcrypto_block_luks_cipher_name_map);
 244     size_t i, j;
 245     for (i = 0; i < maplen; i++) {
 246         for (j = 0; j < map[i].sizes[j].key_bytes; j++) {
 247             if (map[i].sizes[j].id == alg) {
 248                 return map[i].name;
 249             }
 250         }
 251     }
 252
 253     error_setg(errp, "Algorithm '%s' not supported",
 254                QCryptoCipherAlgorithm_lookup[alg]);
 255     return NULL;
 256 }
 257
 258 /* XXX replace with qapi_enum_parse() in future, when we can
 259  * make that function emit a more friendly error message */
 260 static int qcrypto_block_luks_name_lookup(const char *name,
 261                                           const char *const *map,
 262                                           size_t maplen,
 263                                           const char *type,
 264                                           Error **errp)
 265 {
 266     size_t i;
 267     for (i = 0; i < maplen; i++) {
 268         if (g_str_equal(map[i], name)) {
 269             return i;
 270         }
 271     }
 272
 273     error_setg(errp, "%s %s not supported", type, name);
 274     return 0;
 275 }
 276
 277 #define qcrypto_block_luks_cipher_mode_lookup(name, errp)               \
 278     qcrypto_block_luks_name_lookup(name,                                \
 279                                    QCryptoCipherMode_lookup,            \
 280                                    QCRYPTO_CIPHER_MODE__MAX,            \
 281                                    "Cipher mode",                       \
 282                                    errp)
 283
 284 #define qcrypto_block_luks_hash_name_lookup(name, errp)                 \
 285     qcrypto_block_luks_name_lookup(name,                                \
 286                                    QCryptoHashAlgorithm_lookup,         \
 287                                    QCRYPTO_HASH_ALG__MAX,               \
 288                                    "Hash algorithm",                    \
 289                                    errp)
 290
 291 #define qcrypto_block_luks_ivgen_name_lookup(name, errp)                \
 292     qcrypto_block_luks_name_lookup(name,                                \
 293                                    QCryptoIVGenAlgorithm_lookup,        \
 294                                    QCRYPTO_IVGEN_ALG__MAX,              \
 295                                    "IV generator",                      \
 296                                    errp)
 297
 298
 299 static bool
 300 qcrypto_block_luks_has_format(const uint8_t *buf,
 301                               size_t buf_size)
 302 {
 303     const QCryptoBlockLUKSHeader *luks_header = (const void *)buf;
 304
 305     if (buf_size >= offsetof(QCryptoBlockLUKSHeader, cipher_name) &&
 306         memcmp(luks_header->magic, qcrypto_block_luks_magic,
 307                QCRYPTO_BLOCK_LUKS_MAGIC_LEN) == 0 &&
 308         be16_to_cpu(luks_header->version) == QCRYPTO_BLOCK_LUKS_VERSION) {
 309         return true;
 310     } else {
 311         return false;
 312     }
 313 }
 314
 315
 316 /**
 317  * Deal with a quirk of dm-crypt usage of ESSIV.
 318  *
 319  * When calculating ESSIV IVs, the cipher length used by ESSIV
 320  * may be different from the cipher length used for the block
 321  * encryption, becauses dm-crypt uses the hash digest length
 322  * as the key size. ie, if you have AES 128 as the block cipher
 323  * and SHA 256 as ESSIV hash, then ESSIV will use AES 256 as
 324  * the cipher since that gets a key length matching the digest
 325  * size, not AES 128 with truncated digest as might be imagined
 326  */
 327 static QCryptoCipherAlgorithm
 328 qcrypto_block_luks_essiv_cipher(QCryptoCipherAlgorithm cipher,
 329                                 QCryptoHashAlgorithm hash,
 330                                 Error **errp)
 331 {
 332     size_t digestlen = qcrypto_hash_digest_len(hash);
 333     size_t keylen = qcrypto_cipher_get_key_len(cipher);
 334     if (digestlen == keylen) {
 335         return cipher;
 336     }
 337
 338     switch (cipher) {
 339     case QCRYPTO_CIPHER_ALG_AES_128:
 340     case QCRYPTO_CIPHER_ALG_AES_192:
 341     case QCRYPTO_CIPHER_ALG_AES_256:
 342         if (digestlen == qcrypto_cipher_get_key_len(
 343                 QCRYPTO_CIPHER_ALG_AES_128)) {
 344             return QCRYPTO_CIPHER_ALG_AES_128;
 345         } else if (digestlen == qcrypto_cipher_get_key_len(
 346                        QCRYPTO_CIPHER_ALG_AES_192)) {
 347             return QCRYPTO_CIPHER_ALG_AES_192;
 348         } else if (digestlen == qcrypto_cipher_get_key_len(
 349                        QCRYPTO_CIPHER_ALG_AES_256)) {
 350             return QCRYPTO_CIPHER_ALG_AES_256;
 351         } else {
 352             error_setg(errp, "No AES cipher with key size %zu available",
 353                        digestlen);
 354             return 0;
 355         }
 356         break;
 357     case QCRYPTO_CIPHER_ALG_SERPENT_128:
 358     case QCRYPTO_CIPHER_ALG_SERPENT_192:
 359     case QCRYPTO_CIPHER_ALG_SERPENT_256:
 360         if (digestlen == qcrypto_cipher_get_key_len(
 361                 QCRYPTO_CIPHER_ALG_SERPENT_128)) {
 362             return QCRYPTO_CIPHER_ALG_SERPENT_128;
 363         } else if (digestlen == qcrypto_cipher_get_key_len(
 364                        QCRYPTO_CIPHER_ALG_SERPENT_192)) {
 365             return QCRYPTO_CIPHER_ALG_SERPENT_192;
 366         } else if (digestlen == qcrypto_cipher_get_key_len(
 367                        QCRYPTO_CIPHER_ALG_SERPENT_256)) {
 368             return QCRYPTO_CIPHER_ALG_SERPENT_256;
 369         } else {
 370             error_setg(errp, "No Serpent cipher with key size %zu available",
 371                        digestlen);
 372             return 0;
 373         }
 374         break;
 375     case QCRYPTO_CIPHER_ALG_TWOFISH_128:
 376     case QCRYPTO_CIPHER_ALG_TWOFISH_192:
 377     case QCRYPTO_CIPHER_ALG_TWOFISH_256:
 378         if (digestlen == qcrypto_cipher_get_key_len(
 379                 QCRYPTO_CIPHER_ALG_TWOFISH_128)) {
 380             return QCRYPTO_CIPHER_ALG_TWOFISH_128;
 381         } else if (digestlen == qcrypto_cipher_get_key_len(
 382                        QCRYPTO_CIPHER_ALG_TWOFISH_192)) {
 383             return QCRYPTO_CIPHER_ALG_TWOFISH_192;
 384         } else if (digestlen == qcrypto_cipher_get_key_len(
 385                        QCRYPTO_CIPHER_ALG_TWOFISH_256)) {
 386             return QCRYPTO_CIPHER_ALG_TWOFISH_256;
 387         } else {
 388             error_setg(errp, "No Twofish cipher with key size %zu available",
 389                        digestlen);
 390             return 0;
 391         }
 392         break;
 393     default:
 394         error_setg(errp, "Cipher %s not supported with essiv",
 395                    QCryptoCipherAlgorithm_lookup[cipher]);
 396         return 0;
 397     }
 398 }
 399
 400 /*
 401  * Given a key slot, and user password, this will attempt to unlock
 402  * the master encryption key from the key slot.
 403  *
 404  * Returns:
 405  *    0 if the key slot is disabled, or key could not be decrypted
 406  *      with the provided password
 407  *    1 if the key slot is enabled, and key decrypted successfully
 408  *      with the provided password
 409  *   -1 if a fatal error occurred loading the key
 410  */
 411 static int
 412 qcrypto_block_luks_load_key(QCryptoBlock *block,
 413                             QCryptoBlockLUKSKeySlot *slot,
 414                             const char *password,
 415                             QCryptoCipherAlgorithm cipheralg,
 416                             QCryptoCipherMode ciphermode,
 417                             QCryptoHashAlgorithm hash,
 418                             QCryptoIVGenAlgorithm ivalg,
 419                             QCryptoCipherAlgorithm ivcipheralg,
 420                             QCryptoHashAlgorithm ivhash,
 421                             uint8_t *masterkey,
 422                             size_t masterkeylen,
 423                             QCryptoBlockReadFunc readfunc,
 424                             void *opaque,
 425                             Error **errp)
 426 {
 427     QCryptoBlockLUKS *luks = block->opaque;
 428     uint8_t *splitkey;
 429     size_t splitkeylen;
 430     uint8_t *possiblekey;
 431     int ret = -1;
 432     ssize_t rv;
 433     QCryptoCipher *cipher = NULL;
 434     uint8_t keydigest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN];
 435     QCryptoIVGen *ivgen = NULL;
 436     size_t niv;
 437
 438     if (slot->active != QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED) {
 439         return 0;
 440     }
 441
 442     splitkeylen = masterkeylen * slot->stripes;
 443     splitkey = g_new0(uint8_t, splitkeylen);
 444     possiblekey = g_new0(uint8_t, masterkeylen);
 445
 446     /*
 447      * The user password is used to generate a (possible)
 448      * decryption key. This may or may not successfully
 449      * decrypt the master key - we just blindly assume
 450      * the key is correct and validate the results of
 451      * decryption later.
 452      */
 453     if (qcrypto_pbkdf2(hash,
 454                        (const uint8_t *)password, strlen(password),
 455                        slot->salt, QCRYPTO_BLOCK_LUKS_SALT_LEN,
 456                        slot->iterations,
 457                        possiblekey, masterkeylen,
 458                        errp) < 0) {
 459         goto cleanup;
 460     }
 461
 462     /*
 463      * We need to read the master key material from the
 464      * LUKS key material header. What we're reading is
 465      * not the raw master key, but rather the data after
 466      * it has been passed through AFSplit and the result
 467      * then encrypted.
 468      */
 469     rv = readfunc(block,
 470                   slot->key_offset * QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
 471                   splitkey, splitkeylen,
 472                   errp,
 473                   opaque);
 474     if (rv < 0) {
 475         goto cleanup;
 476     }
 477
 478
 479     /* Setup the cipher/ivgen that we'll use to try to decrypt
 480      * the split master key material */
 481     cipher = qcrypto_cipher_new(cipheralg, ciphermode,
 482                                 possiblekey, masterkeylen,
 483                                 errp);
 484     if (!cipher) {
 485         goto cleanup;
 486     }
 487
 488     niv = qcrypto_cipher_get_iv_len(cipheralg,
 489                                     ciphermode);
 490     ivgen = qcrypto_ivgen_new(ivalg,
 491                               ivcipheralg,
 492                               ivhash,
 493                               possiblekey, masterkeylen,
 494                               errp);
 495     if (!ivgen) {
 496         goto cleanup;
 497     }
 498
 499
 500     /*
 501      * The master key needs to be decrypted in the same
 502      * way that the block device payload will be decrypted
 503      * later. In particular we'll be using the IV generator
 504      * to reset the encryption cipher every time the master
 505      * key crosses a sector boundary.
 506      */
 507     if (qcrypto_block_decrypt_helper(cipher,
 508                                      niv,
 509                                      ivgen,
 510                                      QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
 511                                      0,
 512                                      splitkey,
 513                                      splitkeylen,
 514                                      errp) < 0) {
 515         goto cleanup;
 516     }
 517
 518     /*
 519      * Now we've decrypted the split master key, join
 520      * it back together to get the actual master key.
 521      */
 522     if (qcrypto_afsplit_decode(hash,
 523                                masterkeylen,
 524                                slot->stripes,
 525                                splitkey,
 526                                masterkey,
 527                                errp) < 0) {
 528         goto cleanup;
 529     }
 530
 531
 532     /*
 533      * We still don't know that the masterkey we got is valid,
 534      * because we just blindly assumed the user's password
 535      * was correct. This is where we now verify it. We are
 536      * creating a hash of the master key using PBKDF and
 537      * then comparing that to the hash stored in the key slot
 538      * header
 539      */
 540     if (qcrypto_pbkdf2(hash,
 541                        masterkey, masterkeylen,
 542                        luks->header.master_key_salt,
 543                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
 544                        luks->header.master_key_iterations,
 545                        keydigest, G_N_ELEMENTS(keydigest),
 546                        errp) < 0) {
 547         goto cleanup;
 548     }
 549
 550     if (memcmp(keydigest, luks->header.master_key_digest,
 551                QCRYPTO_BLOCK_LUKS_DIGEST_LEN) == 0) {
 552         /* Success, we got the right master key */
 553         ret = 1;
 554         goto cleanup;
 555     }
 556
 557     /* Fail, user's password was not valid for this key slot,
 558      * tell caller to try another slot */
 559     ret = 0;
 560
 561  cleanup:
 562     qcrypto_ivgen_free(ivgen);
 563     qcrypto_cipher_free(cipher);
 564     g_free(splitkey);
 565     g_free(possiblekey);
 566     return ret;
 567 }
 568
 569
 570 /*
 571  * Given a user password, this will iterate over all key
 572  * slots and try to unlock each active key slot using the
 573  * password until it successfully obtains a master key.
 574  *
 575  * Returns 0 if a key was loaded, -1 if no keys could be loaded
 576  */
 577 static int
 578 qcrypto_block_luks_find_key(QCryptoBlock *block,
 579                             const char *password,
 580                             QCryptoCipherAlgorithm cipheralg,
 581                             QCryptoCipherMode ciphermode,
 582                             QCryptoHashAlgorithm hash,
 583                             QCryptoIVGenAlgorithm ivalg,
 584                             QCryptoCipherAlgorithm ivcipheralg,
 585                             QCryptoHashAlgorithm ivhash,
 586                             uint8_t **masterkey,
 587                             size_t *masterkeylen,
 588                             QCryptoBlockReadFunc readfunc,
 589                             void *opaque,
 590                             Error **errp)
 591 {
 592     QCryptoBlockLUKS *luks = block->opaque;
 593     size_t i;
 594     int rv;
 595
 596     *masterkey = g_new0(uint8_t, luks->header.key_bytes);
 597     *masterkeylen = luks->header.key_bytes;
 598
 599     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
 600         rv = qcrypto_block_luks_load_key(block,
 601                                          &luks->header.key_slots[i],
 602                                          password,
 603                                          cipheralg,
 604                                          ciphermode,
 605                                          hash,
 606                                          ivalg,
 607                                          ivcipheralg,
 608                                          ivhash,
 609                                          *masterkey,
 610                                          *masterkeylen,
 611                                          readfunc,
 612                                          opaque,
 613                                          errp);
 614         if (rv < 0) {
 615             goto error;
 616         }
 617         if (rv == 1) {
 618             return 0;
 619         }
 620     }
 621
 622     error_setg(errp, "Invalid password, cannot unlock any keyslot");
 623
 624  error:
 625     g_free(*masterkey);
 626     *masterkey = NULL;
 627     *masterkeylen = 0;
 628     return -1;
 629 }
 630
 631
 632 static int
 633 qcrypto_block_luks_open(QCryptoBlock *block,
 634                         QCryptoBlockOpenOptions *options,
 635                         QCryptoBlockReadFunc readfunc,
 636                         void *opaque,
 637                         unsigned int flags,
 638                         Error **errp)
 639 {
 640     QCryptoBlockLUKS *luks;
 641     Error *local_err = NULL;
 642     int ret = 0;
 643     size_t i;
 644     ssize_t rv;
 645     uint8_t *masterkey = NULL;
 646     size_t masterkeylen;
 647     char *ivgen_name, *ivhash_name;
 648     QCryptoCipherMode ciphermode;
 649     QCryptoCipherAlgorithm cipheralg;
 650     QCryptoIVGenAlgorithm ivalg;
 651     QCryptoCipherAlgorithm ivcipheralg;
 652     QCryptoHashAlgorithm hash;
 653     QCryptoHashAlgorithm ivhash;
 654     char *password = NULL;
 655
 656     if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) {
 657         if (!options->u.luks.key_secret) {
 658             error_setg(errp, "Parameter 'key-secret' is required for cipher");
 659             return -1;
 660         }
 661         password = qcrypto_secret_lookup_as_utf8(
 662             options->u.luks.key_secret, errp);
 663         if (!password) {
 664             return -1;
 665         }
 666     }
 667
 668     luks = g_new0(QCryptoBlockLUKS, 1);
 669     block->opaque = luks;
 670
 671     /* Read the entire LUKS header, minus the key material from
 672      * the underlying device */
 673     rv = readfunc(block, 0,
 674                   (uint8_t *)&luks->header,
 675                   sizeof(luks->header),
 676                   errp,
 677                   opaque);
 678     if (rv < 0) {
 679         ret = rv;
 680         goto fail;
 681     }
 682
 683     /* The header is always stored in big-endian format, so
 684      * convert everything to native */
 685     be16_to_cpus(&luks->header.version);
 686     be32_to_cpus(&luks->header.payload_offset);
 687     be32_to_cpus(&luks->header.key_bytes);
 688     be32_to_cpus(&luks->header.master_key_iterations);
 689
 690     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
 691         be32_to_cpus(&luks->header.key_slots[i].active);
 692         be32_to_cpus(&luks->header.key_slots[i].iterations);
 693         be32_to_cpus(&luks->header.key_slots[i].key_offset);
 694         be32_to_cpus(&luks->header.key_slots[i].stripes);
 695     }
 696
 697     if (memcmp(luks->header.magic, qcrypto_block_luks_magic,
 698                QCRYPTO_BLOCK_LUKS_MAGIC_LEN) != 0) {
 699         error_setg(errp, "Volume is not in LUKS format");
 700         ret = -EINVAL;
 701         goto fail;
 702     }
 703     if (luks->header.version != QCRYPTO_BLOCK_LUKS_VERSION) {
 704         error_setg(errp, "LUKS version %" PRIu32 " is not supported",
 705                    luks->header.version);
 706         ret = -ENOTSUP;
 707         goto fail;
 708     }
 709
 710     /*
 711      * The cipher_mode header contains a string that we have
 712      * to further parse, of the format
 713      *
 714      *    <cipher-mode>-<iv-generator>[:<iv-hash>]
 715      *
 716      * eg  cbc-essiv:sha256, cbc-plain64
 717      */
 718     ivgen_name = strchr(luks->header.cipher_mode, '-');
 719     if (!ivgen_name) {
 720         ret = -EINVAL;
 721         error_setg(errp, "Unexpected cipher mode string format %s",
 722                    luks->header.cipher_mode);
 723         goto fail;
 724     }
 725     *ivgen_name = '\0';
 726     ivgen_name++;
 727
 728     ivhash_name = strchr(ivgen_name, ':');
 729     if (!ivhash_name) {
 730         ivhash = 0;
 731     } else {
 732         *ivhash_name = '\0';
 733         ivhash_name++;
 734
 735         ivhash = qcrypto_block_luks_hash_name_lookup(ivhash_name,
 736                                                      &local_err);
 737         if (local_err) {
 738             ret = -ENOTSUP;
 739             error_propagate(errp, local_err);
 740             goto fail;
 741         }
 742     }
 743
 744     ciphermode = qcrypto_block_luks_cipher_mode_lookup(luks->header.cipher_mode,
 745                                                        &local_err);
 746     if (local_err) {
 747         ret = -ENOTSUP;
 748         error_propagate(errp, local_err);
 749         goto fail;
 750     }
 751
 752     cipheralg = qcrypto_block_luks_cipher_name_lookup(luks->header.cipher_name,
 753                                                       ciphermode,
 754                                                       luks->header.key_bytes,
 755                                                       &local_err);
 756     if (local_err) {
 757         ret = -ENOTSUP;
 758         error_propagate(errp, local_err);
 759         goto fail;
 760     }
 761
 762     hash = qcrypto_block_luks_hash_name_lookup(luks->header.hash_spec,
 763                                                &local_err);
 764     if (local_err) {
 765         ret = -ENOTSUP;
 766         error_propagate(errp, local_err);
 767         goto fail;
 768     }
 769
 770     ivalg = qcrypto_block_luks_ivgen_name_lookup(ivgen_name,
 771                                                  &local_err);
 772     if (local_err) {
 773         ret = -ENOTSUP;
 774         error_propagate(errp, local_err);
 775         goto fail;
 776     }
 777
 778     if (ivalg == QCRYPTO_IVGEN_ALG_ESSIV) {
 779         if (!ivhash_name) {
 780             ret = -EINVAL;
 781             error_setg(errp, "Missing IV generator hash specification");
 782             goto fail;
 783         }
 784         ivcipheralg = qcrypto_block_luks_essiv_cipher(cipheralg,
 785                                                       ivhash,
 786                                                       &local_err);
 787         if (local_err) {
 788             ret = -ENOTSUP;
 789             error_propagate(errp, local_err);
 790             goto fail;
 791         }
 792     } else {
 793         /* Note we parsed the ivhash_name earlier in the cipher_mode
 794          * spec string even with plain/plain64 ivgens, but we
 795          * will ignore it, since it is irrelevant for these ivgens.
 796          * This is for compat with dm-crypt which will silently
 797          * ignore hash names with these ivgens rather than report
 798          * an error about the invalid usage
 799          */
 800         ivcipheralg = cipheralg;
 801     }
 802
 803     if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) {
 804         /* Try to find which key slot our password is valid for
 805          * and unlock the master key from that slot.
 806          */
 807         if (qcrypto_block_luks_find_key(block,
 808                                         password,
 809                                         cipheralg, ciphermode,
 810                                         hash,
 811                                         ivalg,
 812                                         ivcipheralg,
 813                                         ivhash,
 814                                         &masterkey, &masterkeylen,
 815                                         readfunc, opaque,
 816                                         errp) < 0) {
 817             ret = -EACCES;
 818             goto fail;
 819         }
 820
 821         /* We have a valid master key now, so can setup the
 822          * block device payload decryption objects
 823          */
 824         block->kdfhash = hash;
 825         block->niv = qcrypto_cipher_get_iv_len(cipheralg,
 826                                                ciphermode);
 827         block->ivgen = qcrypto_ivgen_new(ivalg,
 828                                          ivcipheralg,
 829                                          ivhash,
 830                                          masterkey, masterkeylen,
 831                                          errp);
 832         if (!block->ivgen) {
 833             ret = -ENOTSUP;
 834             goto fail;
 835         }
 836
 837         block->cipher = qcrypto_cipher_new(cipheralg,
 838                                            ciphermode,
 839                                            masterkey, masterkeylen,
 840                                            errp);
 841         if (!block->cipher) {
 842             ret = -ENOTSUP;
 843             goto fail;
 844         }
 845     }
 846
 847     block->payload_offset = luks->header.payload_offset *
 848         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
 849
 850     g_free(masterkey);
 851     g_free(password);
 852
 853     return 0;
 854
 855  fail:
 856     g_free(masterkey);
 857     qcrypto_cipher_free(block->cipher);
 858     qcrypto_ivgen_free(block->ivgen);
 859     g_free(luks);
 860     g_free(password);
 861     return ret;
 862 }
 863
 864
 865 static int
 866 qcrypto_block_luks_uuid_gen(uint8_t *uuidstr, Error **errp)
 867 {
 868 #ifdef CONFIG_UUID
 869     uuid_t uuid;
 870     uuid_generate(uuid);
 871     uuid_unparse(uuid, (char *)uuidstr);
 872     return 0;
 873 #else
 874     error_setg(errp, "Unable to generate uuids on this platform");
 875     return -1;
 876 #endif
 877 }
 878
 879 static int
 880 qcrypto_block_luks_create(QCryptoBlock *block,
 881                           QCryptoBlockCreateOptions *options,
 882                           QCryptoBlockInitFunc initfunc,
 883                           QCryptoBlockWriteFunc writefunc,
 884                           void *opaque,
 885                           Error **errp)
 886 {
 887     QCryptoBlockLUKS *luks;
 888     QCryptoBlockCreateOptionsLUKS luks_opts;
 889     Error *local_err = NULL;
 890     uint8_t *masterkey = NULL;
 891     uint8_t *slotkey = NULL;
 892     uint8_t *splitkey = NULL;
 893     size_t splitkeylen = 0;
 894     size_t i;
 895     QCryptoCipher *cipher = NULL;
 896     QCryptoIVGen *ivgen = NULL;
 897     char *password;
 898     const char *cipher_alg;
 899     const char *cipher_mode;
 900     const char *ivgen_alg;
 901     const char *ivgen_hash_alg = NULL;
 902     const char *hash_alg;
 903     char *cipher_mode_spec = NULL;
 904     QCryptoCipherAlgorithm ivcipheralg = 0;
 905
 906     memcpy(&luks_opts, &options->u.luks, sizeof(luks_opts));
 907     if (!luks_opts.has_cipher_alg) {
 908         luks_opts.cipher_alg = QCRYPTO_CIPHER_ALG_AES_256;
 909     }
 910     if (!luks_opts.has_cipher_mode) {
 911         luks_opts.cipher_mode = QCRYPTO_CIPHER_MODE_XTS;
 912     }
 913     if (!luks_opts.has_ivgen_alg) {
 914         luks_opts.ivgen_alg = QCRYPTO_IVGEN_ALG_PLAIN64;
 915     }
 916     if (!luks_opts.has_hash_alg) {
 917         luks_opts.hash_alg = QCRYPTO_HASH_ALG_SHA256;
 918     }
 919     if (luks_opts.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
 920         if (!luks_opts.has_ivgen_hash_alg) {
 921             luks_opts.ivgen_hash_alg = QCRYPTO_HASH_ALG_SHA256;
 922             luks_opts.has_ivgen_hash_alg = true;
 923         }
 924     }
 925     /* Note we're allowing ivgen_hash_alg to be set even for
 926      * non-essiv iv generators that don't need a hash. It will
 927      * be silently ignored, for compatibility with dm-crypt */
 928
 929     if (!options->u.luks.key_secret) {
 930         error_setg(errp, "Parameter 'key-secret' is required for cipher");
 931         return -1;
 932     }
 933     password = qcrypto_secret_lookup_as_utf8(luks_opts.key_secret, errp);
 934     if (!password) {
 935         return -1;
 936     }
 937
 938     luks = g_new0(QCryptoBlockLUKS, 1);
 939     block->opaque = luks;
 940
 941     memcpy(luks->header.magic, qcrypto_block_luks_magic,
 942            QCRYPTO_BLOCK_LUKS_MAGIC_LEN);
 943
 944     /* We populate the header in native endianness initially and
 945      * then convert everything to big endian just before writing
 946      * it out to disk
 947      */
 948     luks->header.version = QCRYPTO_BLOCK_LUKS_VERSION;
 949     if (qcrypto_block_luks_uuid_gen(luks->header.uuid,
 950                                     errp) < 0) {
 951         goto error;
 952     }
 953
 954     cipher_alg = qcrypto_block_luks_cipher_alg_lookup(luks_opts.cipher_alg,
 955                                                       errp);
 956     if (!cipher_alg) {
 957         goto error;
 958     }
 959
 960     cipher_mode = QCryptoCipherMode_lookup[luks_opts.cipher_mode];
 961     ivgen_alg = QCryptoIVGenAlgorithm_lookup[luks_opts.ivgen_alg];
 962     if (luks_opts.has_ivgen_hash_alg) {
 963         ivgen_hash_alg = QCryptoHashAlgorithm_lookup[luks_opts.ivgen_hash_alg];
 964         cipher_mode_spec = g_strdup_printf("%s-%s:%s", cipher_mode, ivgen_alg,
 965                                            ivgen_hash_alg);
 966     } else {
 967         cipher_mode_spec = g_strdup_printf("%s-%s", cipher_mode, ivgen_alg);
 968     }
 969     hash_alg = QCryptoHashAlgorithm_lookup[luks_opts.hash_alg];
 970
 971
 972     if (strlen(cipher_alg) >= QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN) {
 973         error_setg(errp, "Cipher name '%s' is too long for LUKS header",
 974                    cipher_alg);
 975         goto error;
 976     }
 977     if (strlen(cipher_mode_spec) >= QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN) {
 978         error_setg(errp, "Cipher mode '%s' is too long for LUKS header",
 979                    cipher_mode_spec);
 980         goto error;
 981     }
 982     if (strlen(hash_alg) >= QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN) {
 983         error_setg(errp, "Hash name '%s' is too long for LUKS header",
 984                    hash_alg);
 985         goto error;
 986     }
 987
 988     if (luks_opts.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
 989         ivcipheralg = qcrypto_block_luks_essiv_cipher(luks_opts.cipher_alg,
 990                                                       luks_opts.ivgen_hash_alg,
 991                                                       &local_err);
 992         if (local_err) {
 993             error_propagate(errp, local_err);
 994             goto error;
 995         }
 996     } else {
 997         ivcipheralg = luks_opts.cipher_alg;
 998     }
 999
1000     strcpy(luks->header.cipher_name, cipher_alg);
1001     strcpy(luks->header.cipher_mode, cipher_mode_spec);
1002     strcpy(luks->header.hash_spec, hash_alg);
1003
1004     luks->header.key_bytes = qcrypto_cipher_get_key_len(luks_opts.cipher_alg);
1005     if (luks_opts.cipher_mode == QCRYPTO_CIPHER_MODE_XTS) {
1006         luks->header.key_bytes *= 2;
1007     }
1008
1009     /* Generate the salt used for hashing the master key
1010      * with PBKDF later
1011      */
1012     if (qcrypto_random_bytes(luks->header.master_key_salt,
1013                              QCRYPTO_BLOCK_LUKS_SALT_LEN,
1014                              errp) < 0) {
1015         goto error;
1016     }
1017
1018     /* Generate random master key */
1019     masterkey = g_new0(uint8_t, luks->header.key_bytes);
1020     if (qcrypto_random_bytes(masterkey,
1021                              luks->header.key_bytes, errp) < 0) {
1022         goto error;
1023     }
1024
1025
1026     /* Setup the block device payload encryption objects */
1027     block->cipher = qcrypto_cipher_new(luks_opts.cipher_alg,
1028                                        luks_opts.cipher_mode,
1029                                        masterkey, luks->header.key_bytes,
1030                                        errp);
1031     if (!block->cipher) {
1032         goto error;
1033     }
1034
1035     block->kdfhash = luks_opts.hash_alg;
1036     block->niv = qcrypto_cipher_get_iv_len(luks_opts.cipher_alg,
1037                                            luks_opts.cipher_mode);
1038     block->ivgen = qcrypto_ivgen_new(luks_opts.ivgen_alg,
1039                                      ivcipheralg,
1040                                      luks_opts.ivgen_hash_alg,
1041                                      masterkey, luks->header.key_bytes,
1042                                      errp);
1043
1044     if (!block->ivgen) {
1045         goto error;
1046     }
1047
1048
1049     /* Determine how many iterations we need to hash the master
1050      * key, in order to have 1 second of compute time used
1051      */
1052     luks->header.master_key_iterations =
1053         qcrypto_pbkdf2_count_iters(luks_opts.hash_alg,
1054                                    masterkey, luks->header.key_bytes,
1055                                    luks->header.master_key_salt,
1056                                    QCRYPTO_BLOCK_LUKS_SALT_LEN,
1057                                    &local_err);
1058     if (local_err) {
1059         error_propagate(errp, local_err);
1060         goto error;
1061     }
1062
1063     /* Why /= 8 ?  That matches cryptsetup, but there's no
1064      * explanation why they chose /= 8... Probably so that
1065      * if all 8 keyslots are active we only spend 1 second
1066      * in total time to check all keys */
1067     luks->header.master_key_iterations /= 8;
1068     luks->header.master_key_iterations = MAX(
1069         luks->header.master_key_iterations,
1070         QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS);
1071
1072
1073     /* Hash the master key, saving the result in the LUKS
1074      * header. This hash is used when opening the encrypted
1075      * device to verify that the user password unlocked a
1076      * valid master key
1077      */
1078     if (qcrypto_pbkdf2(luks_opts.hash_alg,
1079                        masterkey, luks->header.key_bytes,
1080                        luks->header.master_key_salt,
1081                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1082                        luks->header.master_key_iterations,
1083                        luks->header.master_key_digest,
1084                        QCRYPTO_BLOCK_LUKS_DIGEST_LEN,
1085                        errp) < 0) {
1086         goto error;
1087     }
1088
1089
1090     /* Although LUKS has multiple key slots, we're just going
1091      * to use the first key slot */
1092     splitkeylen = luks->header.key_bytes * QCRYPTO_BLOCK_LUKS_STRIPES;
1093     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1094         luks->header.key_slots[i].active = i == 0 ?
1095             QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED :
1096             QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED;
1097         luks->header.key_slots[i].stripes = QCRYPTO_BLOCK_LUKS_STRIPES;
1098
1099         /* This calculation doesn't match that shown in the spec,
1100          * but instead follows the cryptsetup implementation.
1101          */
1102         luks->header.key_slots[i].key_offset =
1103             (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1104              QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) +
1105             (ROUND_UP(DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE),
1106                       (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1107                        QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) * i);
1108     }
1109
1110     if (qcrypto_random_bytes(luks->header.key_slots[0].salt,
1111                              QCRYPTO_BLOCK_LUKS_SALT_LEN,
1112                              errp) < 0) {
1113         goto error;
1114     }
1115
1116     /* Again we determine how many iterations are required to
1117      * hash the user password while consuming 1 second of compute
1118      * time */
1119     luks->header.key_slots[0].iterations =
1120         qcrypto_pbkdf2_count_iters(luks_opts.hash_alg,
1121                                    (uint8_t *)password, strlen(password),
1122                                    luks->header.key_slots[0].salt,
1123                                    QCRYPTO_BLOCK_LUKS_SALT_LEN,
1124                                    &local_err);
1125     if (local_err) {
1126         error_propagate(errp, local_err);
1127         goto error;
1128     }
1129     /* Why /= 2 ?  That matches cryptsetup, but there's no
1130      * explanation why they chose /= 2... */
1131     luks->header.key_slots[0].iterations /= 2;
1132     luks->header.key_slots[0].iterations = MAX(
1133         luks->header.key_slots[0].iterations,
1134         QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS);
1135
1136
1137     /* Generate a key that we'll use to encrypt the master
1138      * key, from the user's password
1139      */
1140     slotkey = g_new0(uint8_t, luks->header.key_bytes);
1141     if (qcrypto_pbkdf2(luks_opts.hash_alg,
1142                        (uint8_t *)password, strlen(password),
1143                        luks->header.key_slots[0].salt,
1144                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1145                        luks->header.key_slots[0].iterations,
1146                        slotkey, luks->header.key_bytes,
1147                        errp) < 0) {
1148         goto error;
1149     }
1150
1151
1152     /* Setup the encryption objects needed to encrypt the
1153      * master key material
1154      */
1155     cipher = qcrypto_cipher_new(luks_opts.cipher_alg,
1156                                 luks_opts.cipher_mode,
1157                                 slotkey, luks->header.key_bytes,
1158                                 errp);
1159     if (!cipher) {
1160         goto error;
1161     }
1162
1163     ivgen = qcrypto_ivgen_new(luks_opts.ivgen_alg,
1164                               ivcipheralg,
1165                               luks_opts.ivgen_hash_alg,
1166                               slotkey, luks->header.key_bytes,
1167                               errp);
1168     if (!ivgen) {
1169         goto error;
1170     }
1171
1172     /* Before storing the master key, we need to vastly
1173      * increase its size, as protection against forensic
1174      * disk data recovery */
1175     splitkey = g_new0(uint8_t, splitkeylen);
1176
1177     if (qcrypto_afsplit_encode(luks_opts.hash_alg,
1178                                luks->header.key_bytes,
1179                                luks->header.key_slots[0].stripes,
1180                                masterkey,
1181                                splitkey,
1182                                errp) < 0) {
1183         goto error;
1184     }
1185
1186     /* Now we encrypt the split master key with the key generated
1187      * from the user's password, before storing it */
1188     if (qcrypto_block_encrypt_helper(cipher, block->niv, ivgen,
1189                                      QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1190                                      0,
1191                                      splitkey,
1192                                      splitkeylen,
1193                                      errp) < 0) {
1194         goto error;
1195     }
1196
1197
1198     /* The total size of the LUKS headers is the partition header + key
1199      * slot headers, rounded up to the nearest sector, combined with
1200      * the size of each master key material region, also rounded up
1201      * to the nearest sector */
1202     luks->header.payload_offset =
1203         (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1204          QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) +
1205         (ROUND_UP(DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE),
1206                   (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1207                    QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) *
1208          QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS);
1209
1210     block->payload_offset = luks->header.payload_offset *
1211         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
1212
1213     /* Reserve header space to match payload offset */
1214     initfunc(block, block->payload_offset, &local_err, opaque);
1215     if (local_err) {
1216         error_propagate(errp, local_err);
1217         goto error;
1218     }
1219
1220     /* Everything on disk uses Big Endian, so flip header fields
1221      * before writing them */
1222     cpu_to_be16s(&luks->header.version);
1223     cpu_to_be32s(&luks->header.payload_offset);
1224     cpu_to_be32s(&luks->header.key_bytes);
1225     cpu_to_be32s(&luks->header.master_key_iterations);
1226
1227     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1228         cpu_to_be32s(&luks->header.key_slots[i].active);
1229         cpu_to_be32s(&luks->header.key_slots[i].iterations);
1230         cpu_to_be32s(&luks->header.key_slots[i].key_offset);
1231         cpu_to_be32s(&luks->header.key_slots[i].stripes);
1232     }
1233
1234
1235     /* Write out the partition header and key slot headers */
1236     writefunc(block, 0,
1237               (const uint8_t *)&luks->header,
1238               sizeof(luks->header),
1239               &local_err,
1240               opaque);
1241
1242     /* Delay checking local_err until we've byte-swapped */
1243
1244     /* Byte swap the header back to native, in case we need
1245      * to read it again later */
1246     be16_to_cpus(&luks->header.version);
1247     be32_to_cpus(&luks->header.payload_offset);
1248     be32_to_cpus(&luks->header.key_bytes);
1249     be32_to_cpus(&luks->header.master_key_iterations);
1250
1251     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1252         be32_to_cpus(&luks->header.key_slots[i].active);
1253         be32_to_cpus(&luks->header.key_slots[i].iterations);
1254         be32_to_cpus(&luks->header.key_slots[i].key_offset);
1255         be32_to_cpus(&luks->header.key_slots[i].stripes);
1256     }
1257
1258     if (local_err) {
1259         error_propagate(errp, local_err);
1260         goto error;
1261     }
1262
1263     /* Write out the master key material, starting at the
1264      * sector immediately following the partition header. */
1265     if (writefunc(block,
1266                   luks->header.key_slots[0].key_offset *
1267                   QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1268                   splitkey, splitkeylen,
1269                   errp,
1270                   opaque) != splitkeylen) {
1271         goto error;
1272     }
1273
1274     memset(masterkey, 0, luks->header.key_bytes);
1275     g_free(masterkey);
1276     memset(slotkey, 0, luks->header.key_bytes);
1277     g_free(slotkey);
1278     g_free(splitkey);
1279     g_free(password);
1280     g_free(cipher_mode_spec);
1281
1282     qcrypto_ivgen_free(ivgen);
1283     qcrypto_cipher_free(cipher);
1284
1285     return 0;
1286
1287  error:
1288     if (masterkey) {
1289         memset(masterkey, 0, luks->header.key_bytes);
1290     }
1291     g_free(masterkey);
1292     if (slotkey) {
1293         memset(slotkey, 0, luks->header.key_bytes);
1294     }
1295     g_free(slotkey);
1296     g_free(splitkey);
1297     g_free(password);
1298     g_free(cipher_mode_spec);
1299
1300     qcrypto_ivgen_free(ivgen);
1301     qcrypto_cipher_free(cipher);
1302
1303     g_free(luks);
1304     return -1;
1305 }
1306
1307
1308 static void qcrypto_block_luks_cleanup(QCryptoBlock *block)
1309 {
1310     g_free(block->opaque);
1311 }
1312
1313
1314 static int
1315 qcrypto_block_luks_decrypt(QCryptoBlock *block,
1316                            uint64_t startsector,
1317                            uint8_t *buf,
1318                            size_t len,
1319                            Error **errp)
1320 {
1321     return qcrypto_block_decrypt_helper(block->cipher,
1322                                         block->niv, block->ivgen,
1323                                         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1324                                         startsector, buf, len, errp);
1325 }
1326
1327
1328 static int
1329 qcrypto_block_luks_encrypt(QCryptoBlock *block,
1330                            uint64_t startsector,
1331                            uint8_t *buf,
1332                            size_t len,
1333                            Error **errp)
1334 {
1335     return qcrypto_block_encrypt_helper(block->cipher,
1336                                         block->niv, block->ivgen,
1337                                         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1338                                         startsector, buf, len, errp);
1339 }
1340
1341
1342 const QCryptoBlockDriver qcrypto_block_driver_luks = {
1343     .open = qcrypto_block_luks_open,
1344     .create = qcrypto_block_luks_create,
1345     .cleanup = qcrypto_block_luks_cleanup,
1346     .decrypt = qcrypto_block_luks_decrypt,
1347     .encrypt = qcrypto_block_luks_encrypt,
1348     .has_format = qcrypto_block_luks_has_format,
1349 };