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 "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 #include "qemu/uuid.h"
  33
  34 #include "qemu/coroutine.h"
  35
  36 /*
  37  * Reference for the LUKS format implemented here is
  38  *
  39  *   docs/on-disk-format.pdf
  40  *
  41  * in 'cryptsetup' package source code
  42  *
  43  * This file implements the 1.2.1 specification, dated
  44  * Oct 16, 2011.
  45  */
  46
  47 typedef struct QCryptoBlockLUKS QCryptoBlockLUKS;
  48 typedef struct QCryptoBlockLUKSHeader QCryptoBlockLUKSHeader;
  49 typedef struct QCryptoBlockLUKSKeySlot QCryptoBlockLUKSKeySlot;
  50
  51
  52 /* The following constants are all defined by the LUKS spec */
  53 #define QCRYPTO_BLOCK_LUKS_VERSION 1
  54
  55 #define QCRYPTO_BLOCK_LUKS_MAGIC_LEN 6
  56 #define QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN 32
  57 #define QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN 32
  58 #define QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN 32
  59 #define QCRYPTO_BLOCK_LUKS_DIGEST_LEN 20
  60 #define QCRYPTO_BLOCK_LUKS_SALT_LEN 32
  61 #define QCRYPTO_BLOCK_LUKS_UUID_LEN 40
  62 #define QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS 8
  63 #define QCRYPTO_BLOCK_LUKS_STRIPES 4000
  64 #define QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS 1000
  65 #define QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS 1000
  66 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET 4096
  67
  68 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED 0x0000DEAD
  69 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED 0x00AC71F3
  70
  71 #define QCRYPTO_BLOCK_LUKS_SECTOR_SIZE 512LL
  72
  73 static const char qcrypto_block_luks_magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN] = {
  74     'L', 'U', 'K', 'S', 0xBA, 0xBE
  75 };
  76
  77 typedef struct QCryptoBlockLUKSNameMap QCryptoBlockLUKSNameMap;
  78 struct QCryptoBlockLUKSNameMap {
  79     const char *name;
  80     int id;
  81 };
  82
  83 typedef struct QCryptoBlockLUKSCipherSizeMap QCryptoBlockLUKSCipherSizeMap;
  84 struct QCryptoBlockLUKSCipherSizeMap {
  85     uint32_t key_bytes;
  86     int id;
  87 };
  88 typedef struct QCryptoBlockLUKSCipherNameMap QCryptoBlockLUKSCipherNameMap;
  89 struct QCryptoBlockLUKSCipherNameMap {
  90     const char *name;
  91     const QCryptoBlockLUKSCipherSizeMap *sizes;
  92 };
  93
  94
  95 static const QCryptoBlockLUKSCipherSizeMap
  96 qcrypto_block_luks_cipher_size_map_aes[] = {
  97     { 16, QCRYPTO_CIPHER_ALG_AES_128 },
  98     { 24, QCRYPTO_CIPHER_ALG_AES_192 },
  99     { 32, QCRYPTO_CIPHER_ALG_AES_256 },
 100     { 0, 0 },
 101 };
 102
 103 static const QCryptoBlockLUKSCipherSizeMap
 104 qcrypto_block_luks_cipher_size_map_cast5[] = {
 105     { 16, QCRYPTO_CIPHER_ALG_CAST5_128 },
 106     { 0, 0 },
 107 };
 108
 109 static const QCryptoBlockLUKSCipherSizeMap
 110 qcrypto_block_luks_cipher_size_map_serpent[] = {
 111     { 16, QCRYPTO_CIPHER_ALG_SERPENT_128 },
 112     { 24, QCRYPTO_CIPHER_ALG_SERPENT_192 },
 113     { 32, QCRYPTO_CIPHER_ALG_SERPENT_256 },
 114     { 0, 0 },
 115 };
 116
 117 static const QCryptoBlockLUKSCipherSizeMap
 118 qcrypto_block_luks_cipher_size_map_twofish[] = {
 119     { 16, QCRYPTO_CIPHER_ALG_TWOFISH_128 },
 120     { 24, QCRYPTO_CIPHER_ALG_TWOFISH_192 },
 121     { 32, QCRYPTO_CIPHER_ALG_TWOFISH_256 },
 122     { 0, 0 },
 123 };
 124
 125 static const QCryptoBlockLUKSCipherNameMap
 126 qcrypto_block_luks_cipher_name_map[] = {
 127     { "aes", qcrypto_block_luks_cipher_size_map_aes },
 128     { "cast5", qcrypto_block_luks_cipher_size_map_cast5 },
 129     { "serpent", qcrypto_block_luks_cipher_size_map_serpent },
 130     { "twofish", qcrypto_block_luks_cipher_size_map_twofish },
 131 };
 132
 133
 134 /*
 135  * This struct is written to disk in big-endian format,
 136  * but operated upon in native-endian format.
 137  */
 138 struct QCryptoBlockLUKSKeySlot {
 139     /* state of keyslot, enabled/disable */
 140     uint32_t active;
 141     /* iterations for PBKDF2 */
 142     uint32_t iterations;
 143     /* salt for PBKDF2 */
 144     uint8_t salt[QCRYPTO_BLOCK_LUKS_SALT_LEN];
 145     /* start sector of key material */
 146     uint32_t key_offset;
 147     /* number of anti-forensic stripes */
 148     uint32_t stripes;
 149 } QEMU_PACKED;
 150
 151 QEMU_BUILD_BUG_ON(sizeof(struct QCryptoBlockLUKSKeySlot) != 48);
 152
 153
 154 /*
 155  * This struct is written to disk in big-endian format,
 156  * but operated upon in native-endian format.
 157  */
 158 struct QCryptoBlockLUKSHeader {
 159     /* 'L', 'U', 'K', 'S', '0xBA', '0xBE' */
 160     char magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN];
 161
 162     /* LUKS version, currently 1 */
 163     uint16_t version;
 164
 165     /* cipher name specification (aes, etc) */
 166     char cipher_name[QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN];
 167
 168     /* cipher mode specification (cbc-plain, xts-essiv:sha256, etc) */
 169     char cipher_mode[QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN];
 170
 171     /* hash specification (sha256, etc) */
 172     char hash_spec[QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN];
 173
 174     /* start offset of the volume data (in 512 byte sectors) */
 175     uint32_t payload_offset;
 176
 177     /* Number of key bytes */
 178     uint32_t key_bytes;
 179
 180     /* master key checksum after PBKDF2 */
 181     uint8_t master_key_digest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN];
 182
 183     /* salt for master key PBKDF2 */
 184     uint8_t master_key_salt[QCRYPTO_BLOCK_LUKS_SALT_LEN];
 185
 186     /* iterations for master key PBKDF2 */
 187     uint32_t master_key_iterations;
 188
 189     /* UUID of the partition in standard ASCII representation */
 190     uint8_t uuid[QCRYPTO_BLOCK_LUKS_UUID_LEN];
 191
 192     /* key slots */
 193     QCryptoBlockLUKSKeySlot key_slots[QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS];
 194 } QEMU_PACKED;
 195
 196 QEMU_BUILD_BUG_ON(sizeof(struct QCryptoBlockLUKSHeader) != 592);
 197
 198
 199 struct QCryptoBlockLUKS {
 200     QCryptoBlockLUKSHeader header;
 201
 202     /* Cache parsed versions of what's in header fields,
 203      * as we can't rely on QCryptoBlock.cipher being
 204      * non-NULL */
 205     QCryptoCipherAlgorithm cipher_alg;
 206     QCryptoCipherMode cipher_mode;
 207     QCryptoIVGenAlgorithm ivgen_alg;
 208     QCryptoHashAlgorithm ivgen_hash_alg;
 209     QCryptoHashAlgorithm hash_alg;
 210 };
 211
 212
 213 static int qcrypto_block_luks_cipher_name_lookup(const char *name,
 214                                                  QCryptoCipherMode mode,
 215                                                  uint32_t key_bytes,
 216                                                  Error **errp)
 217 {
 218     const QCryptoBlockLUKSCipherNameMap *map =
 219         qcrypto_block_luks_cipher_name_map;
 220     size_t maplen = G_N_ELEMENTS(qcrypto_block_luks_cipher_name_map);
 221     size_t i, j;
 222
 223     if (mode == QCRYPTO_CIPHER_MODE_XTS) {
 224         key_bytes /= 2;
 225     }
 226
 227     for (i = 0; i < maplen; i++) {
 228         if (!g_str_equal(map[i].name, name)) {
 229             continue;
 230         }
 231         for (j = 0; j < map[i].sizes[j].key_bytes; j++) {
 232             if (map[i].sizes[j].key_bytes == key_bytes) {
 233                 return map[i].sizes[j].id;
 234             }
 235         }
 236     }
 237
 238     error_setg(errp, "Algorithm %s with key size %d bytes not supported",
 239                name, key_bytes);
 240     return 0;
 241 }
 242
 243 static const char *
 244 qcrypto_block_luks_cipher_alg_lookup(QCryptoCipherAlgorithm alg,
 245                                      Error **errp)
 246 {
 247     const QCryptoBlockLUKSCipherNameMap *map =
 248         qcrypto_block_luks_cipher_name_map;
 249     size_t maplen = G_N_ELEMENTS(qcrypto_block_luks_cipher_name_map);
 250     size_t i, j;
 251     for (i = 0; i < maplen; i++) {
 252         for (j = 0; j < map[i].sizes[j].key_bytes; j++) {
 253             if (map[i].sizes[j].id == alg) {
 254                 return map[i].name;
 255             }
 256         }
 257     }
 258
 259     error_setg(errp, "Algorithm '%s' not supported",
 260                QCryptoCipherAlgorithm_str(alg));
 261     return NULL;
 262 }
 263
 264 /* XXX replace with qapi_enum_parse() in future, when we can
 265  * make that function emit a more friendly error message */
 266 static int qcrypto_block_luks_name_lookup(const char *name,
 267                                           const QEnumLookup *map,
 268                                           const char *type,
 269                                           Error **errp)
 270 {
 271     int ret = qapi_enum_parse(map, name, -1, NULL);
 272
 273     if (ret < 0) {
 274         error_setg(errp, "%s %s not supported", type, name);
 275         return 0;
 276     }
 277     return ret;
 278 }
 279
 280 #define qcrypto_block_luks_cipher_mode_lookup(name, errp)               \
 281     qcrypto_block_luks_name_lookup(name,                                \
 282                                    &QCryptoCipherMode_lookup,           \
 283                                    "Cipher mode",                       \
 284                                    errp)
 285
 286 #define qcrypto_block_luks_hash_name_lookup(name, errp)                 \
 287     qcrypto_block_luks_name_lookup(name,                                \
 288                                    &QCryptoHashAlgorithm_lookup,        \
 289                                    "Hash algorithm",                    \
 290                                    errp)
 291
 292 #define qcrypto_block_luks_ivgen_name_lookup(name, errp)                \
 293     qcrypto_block_luks_name_lookup(name,                                \
 294                                    &QCryptoIVGenAlgorithm_lookup,       \
 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_str(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                   opaque,
 473                   errp);
 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                         const char *optprefix,
 636                         QCryptoBlockReadFunc readfunc,
 637                         void *opaque,
 638                         unsigned int flags,
 639                         Error **errp)
 640 {
 641     QCryptoBlockLUKS *luks;
 642     Error *local_err = NULL;
 643     int ret = 0;
 644     size_t i;
 645     ssize_t rv;
 646     uint8_t *masterkey = NULL;
 647     size_t masterkeylen;
 648     char *ivgen_name, *ivhash_name;
 649     QCryptoCipherMode ciphermode;
 650     QCryptoCipherAlgorithm cipheralg;
 651     QCryptoIVGenAlgorithm ivalg;
 652     QCryptoCipherAlgorithm ivcipheralg;
 653     QCryptoHashAlgorithm hash;
 654     QCryptoHashAlgorithm ivhash;
 655     char *password = NULL;
 656
 657     if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) {
 658         if (!options->u.luks.key_secret) {
 659             error_setg(errp, "Parameter '%skey-secret' is required for cipher",
 660                        optprefix ? optprefix : "");
 661             return -1;
 662         }
 663         password = qcrypto_secret_lookup_as_utf8(
 664             options->u.luks.key_secret, errp);
 665         if (!password) {
 666             return -1;
 667         }
 668     }
 669
 670     luks = g_new0(QCryptoBlockLUKS, 1);
 671     block->opaque = luks;
 672
 673     /* Read the entire LUKS header, minus the key material from
 674      * the underlying device */
 675     rv = readfunc(block, 0,
 676                   (uint8_t *)&luks->header,
 677                   sizeof(luks->header),
 678                   opaque,
 679                   errp);
 680     if (rv < 0) {
 681         ret = rv;
 682         goto fail;
 683     }
 684
 685     /* The header is always stored in big-endian format, so
 686      * convert everything to native */
 687     be16_to_cpus(&luks->header.version);
 688     be32_to_cpus(&luks->header.payload_offset);
 689     be32_to_cpus(&luks->header.key_bytes);
 690     be32_to_cpus(&luks->header.master_key_iterations);
 691
 692     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
 693         be32_to_cpus(&luks->header.key_slots[i].active);
 694         be32_to_cpus(&luks->header.key_slots[i].iterations);
 695         be32_to_cpus(&luks->header.key_slots[i].key_offset);
 696         be32_to_cpus(&luks->header.key_slots[i].stripes);
 697     }
 698
 699     if (memcmp(luks->header.magic, qcrypto_block_luks_magic,
 700                QCRYPTO_BLOCK_LUKS_MAGIC_LEN) != 0) {
 701         error_setg(errp, "Volume is not in LUKS format");
 702         ret = -EINVAL;
 703         goto fail;
 704     }
 705     if (luks->header.version != QCRYPTO_BLOCK_LUKS_VERSION) {
 706         error_setg(errp, "LUKS version %" PRIu32 " is not supported",
 707                    luks->header.version);
 708         ret = -ENOTSUP;
 709         goto fail;
 710     }
 711
 712     /*
 713      * The cipher_mode header contains a string that we have
 714      * to further parse, of the format
 715      *
 716      *    <cipher-mode>-<iv-generator>[:<iv-hash>]
 717      *
 718      * eg  cbc-essiv:sha256, cbc-plain64
 719      */
 720     ivgen_name = strchr(luks->header.cipher_mode, '-');
 721     if (!ivgen_name) {
 722         ret = -EINVAL;
 723         error_setg(errp, "Unexpected cipher mode string format %s",
 724                    luks->header.cipher_mode);
 725         goto fail;
 726     }
 727     *ivgen_name = '\0';
 728     ivgen_name++;
 729
 730     ivhash_name = strchr(ivgen_name, ':');
 731     if (!ivhash_name) {
 732         ivhash = 0;
 733     } else {
 734         *ivhash_name = '\0';
 735         ivhash_name++;
 736
 737         ivhash = qcrypto_block_luks_hash_name_lookup(ivhash_name,
 738                                                      &local_err);
 739         if (local_err) {
 740             ret = -ENOTSUP;
 741             error_propagate(errp, local_err);
 742             goto fail;
 743         }
 744     }
 745
 746     ciphermode = qcrypto_block_luks_cipher_mode_lookup(luks->header.cipher_mode,
 747                                                        &local_err);
 748     if (local_err) {
 749         ret = -ENOTSUP;
 750         error_propagate(errp, local_err);
 751         goto fail;
 752     }
 753
 754     cipheralg = qcrypto_block_luks_cipher_name_lookup(luks->header.cipher_name,
 755                                                       ciphermode,
 756                                                       luks->header.key_bytes,
 757                                                       &local_err);
 758     if (local_err) {
 759         ret = -ENOTSUP;
 760         error_propagate(errp, local_err);
 761         goto fail;
 762     }
 763
 764     hash = qcrypto_block_luks_hash_name_lookup(luks->header.hash_spec,
 765                                                &local_err);
 766     if (local_err) {
 767         ret = -ENOTSUP;
 768         error_propagate(errp, local_err);
 769         goto fail;
 770     }
 771
 772     ivalg = qcrypto_block_luks_ivgen_name_lookup(ivgen_name,
 773                                                  &local_err);
 774     if (local_err) {
 775         ret = -ENOTSUP;
 776         error_propagate(errp, local_err);
 777         goto fail;
 778     }
 779
 780     if (ivalg == QCRYPTO_IVGEN_ALG_ESSIV) {
 781         if (!ivhash_name) {
 782             ret = -EINVAL;
 783             error_setg(errp, "Missing IV generator hash specification");
 784             goto fail;
 785         }
 786         ivcipheralg = qcrypto_block_luks_essiv_cipher(cipheralg,
 787                                                       ivhash,
 788                                                       &local_err);
 789         if (local_err) {
 790             ret = -ENOTSUP;
 791             error_propagate(errp, local_err);
 792             goto fail;
 793         }
 794     } else {
 795         /* Note we parsed the ivhash_name earlier in the cipher_mode
 796          * spec string even with plain/plain64 ivgens, but we
 797          * will ignore it, since it is irrelevant for these ivgens.
 798          * This is for compat with dm-crypt which will silently
 799          * ignore hash names with these ivgens rather than report
 800          * an error about the invalid usage
 801          */
 802         ivcipheralg = cipheralg;
 803     }
 804
 805     if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) {
 806         /* Try to find which key slot our password is valid for
 807          * and unlock the master key from that slot.
 808          */
 809         if (qcrypto_block_luks_find_key(block,
 810                                         password,
 811                                         cipheralg, ciphermode,
 812                                         hash,
 813                                         ivalg,
 814                                         ivcipheralg,
 815                                         ivhash,
 816                                         &masterkey, &masterkeylen,
 817                                         readfunc, opaque,
 818                                         errp) < 0) {
 819             ret = -EACCES;
 820             goto fail;
 821         }
 822
 823         /* We have a valid master key now, so can setup the
 824          * block device payload decryption objects
 825          */
 826         block->kdfhash = hash;
 827         block->niv = qcrypto_cipher_get_iv_len(cipheralg,
 828                                                ciphermode);
 829         block->ivgen = qcrypto_ivgen_new(ivalg,
 830                                          ivcipheralg,
 831                                          ivhash,
 832                                          masterkey, masterkeylen,
 833                                          errp);
 834         if (!block->ivgen) {
 835             ret = -ENOTSUP;
 836             goto fail;
 837         }
 838
 839         block->cipher = qcrypto_cipher_new(cipheralg,
 840                                            ciphermode,
 841                                            masterkey, masterkeylen,
 842                                            errp);
 843         if (!block->cipher) {
 844             ret = -ENOTSUP;
 845             goto fail;
 846         }
 847     }
 848
 849     block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
 850     block->payload_offset = luks->header.payload_offset *
 851         block->sector_size;
 852
 853     luks->cipher_alg = cipheralg;
 854     luks->cipher_mode = ciphermode;
 855     luks->ivgen_alg = ivalg;
 856     luks->ivgen_hash_alg = ivhash;
 857     luks->hash_alg = hash;
 858
 859     g_free(masterkey);
 860     g_free(password);
 861
 862     return 0;
 863
 864  fail:
 865     g_free(masterkey);
 866     qcrypto_cipher_free(block->cipher);
 867     qcrypto_ivgen_free(block->ivgen);
 868     g_free(luks);
 869     g_free(password);
 870     return ret;
 871 }
 872
 873
 874 static void
 875 qcrypto_block_luks_uuid_gen(uint8_t *uuidstr)
 876 {
 877     QemuUUID uuid;
 878     qemu_uuid_generate(&uuid);
 879     qemu_uuid_unparse(&uuid, (char *)uuidstr);
 880 }
 881
 882 static int
 883 qcrypto_block_luks_create(QCryptoBlock *block,
 884                           QCryptoBlockCreateOptions *options,
 885                           const char *optprefix,
 886                           QCryptoBlockInitFunc initfunc,
 887                           QCryptoBlockWriteFunc writefunc,
 888                           void *opaque,
 889                           Error **errp)
 890 {
 891     QCryptoBlockLUKS *luks;
 892     QCryptoBlockCreateOptionsLUKS luks_opts;
 893     Error *local_err = NULL;
 894     uint8_t *masterkey = NULL;
 895     uint8_t *slotkey = NULL;
 896     uint8_t *splitkey = NULL;
 897     size_t splitkeylen = 0;
 898     size_t i;
 899     QCryptoCipher *cipher = NULL;
 900     QCryptoIVGen *ivgen = NULL;
 901     char *password;
 902     const char *cipher_alg;
 903     const char *cipher_mode;
 904     const char *ivgen_alg;
 905     const char *ivgen_hash_alg = NULL;
 906     const char *hash_alg;
 907     char *cipher_mode_spec = NULL;
 908     QCryptoCipherAlgorithm ivcipheralg = 0;
 909     uint64_t iters;
 910
 911     memcpy(&luks_opts, &options->u.luks, sizeof(luks_opts));
 912     if (!luks_opts.has_iter_time) {
 913         luks_opts.iter_time = 2000;
 914     }
 915     if (!luks_opts.has_cipher_alg) {
 916         luks_opts.cipher_alg = QCRYPTO_CIPHER_ALG_AES_256;
 917     }
 918     if (!luks_opts.has_cipher_mode) {
 919         luks_opts.cipher_mode = QCRYPTO_CIPHER_MODE_XTS;
 920     }
 921     if (!luks_opts.has_ivgen_alg) {
 922         luks_opts.ivgen_alg = QCRYPTO_IVGEN_ALG_PLAIN64;
 923     }
 924     if (!luks_opts.has_hash_alg) {
 925         luks_opts.hash_alg = QCRYPTO_HASH_ALG_SHA256;
 926     }
 927     if (luks_opts.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
 928         if (!luks_opts.has_ivgen_hash_alg) {
 929             luks_opts.ivgen_hash_alg = QCRYPTO_HASH_ALG_SHA256;
 930             luks_opts.has_ivgen_hash_alg = true;
 931         }
 932     }
 933     /* Note we're allowing ivgen_hash_alg to be set even for
 934      * non-essiv iv generators that don't need a hash. It will
 935      * be silently ignored, for compatibility with dm-crypt */
 936
 937     if (!options->u.luks.key_secret) {
 938         error_setg(errp, "Parameter '%skey-secret' is required for cipher",
 939                    optprefix ? optprefix : "");
 940         return -1;
 941     }
 942     password = qcrypto_secret_lookup_as_utf8(luks_opts.key_secret, errp);
 943     if (!password) {
 944         return -1;
 945     }
 946
 947     luks = g_new0(QCryptoBlockLUKS, 1);
 948     block->opaque = luks;
 949
 950     memcpy(luks->header.magic, qcrypto_block_luks_magic,
 951            QCRYPTO_BLOCK_LUKS_MAGIC_LEN);
 952
 953     /* We populate the header in native endianness initially and
 954      * then convert everything to big endian just before writing
 955      * it out to disk
 956      */
 957     luks->header.version = QCRYPTO_BLOCK_LUKS_VERSION;
 958     qcrypto_block_luks_uuid_gen(luks->header.uuid);
 959
 960     cipher_alg = qcrypto_block_luks_cipher_alg_lookup(luks_opts.cipher_alg,
 961                                                       errp);
 962     if (!cipher_alg) {
 963         goto error;
 964     }
 965
 966     cipher_mode = QCryptoCipherMode_str(luks_opts.cipher_mode);
 967     ivgen_alg = QCryptoIVGenAlgorithm_str(luks_opts.ivgen_alg);
 968     if (luks_opts.has_ivgen_hash_alg) {
 969         ivgen_hash_alg = QCryptoHashAlgorithm_str(luks_opts.ivgen_hash_alg);
 970         cipher_mode_spec = g_strdup_printf("%s-%s:%s", cipher_mode, ivgen_alg,
 971                                            ivgen_hash_alg);
 972     } else {
 973         cipher_mode_spec = g_strdup_printf("%s-%s", cipher_mode, ivgen_alg);
 974     }
 975     hash_alg = QCryptoHashAlgorithm_str(luks_opts.hash_alg);
 976
 977
 978     if (strlen(cipher_alg) >= QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN) {
 979         error_setg(errp, "Cipher name '%s' is too long for LUKS header",
 980                    cipher_alg);
 981         goto error;
 982     }
 983     if (strlen(cipher_mode_spec) >= QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN) {
 984         error_setg(errp, "Cipher mode '%s' is too long for LUKS header",
 985                    cipher_mode_spec);
 986         goto error;
 987     }
 988     if (strlen(hash_alg) >= QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN) {
 989         error_setg(errp, "Hash name '%s' is too long for LUKS header",
 990                    hash_alg);
 991         goto error;
 992     }
 993
 994     if (luks_opts.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
 995         ivcipheralg = qcrypto_block_luks_essiv_cipher(luks_opts.cipher_alg,
 996                                                       luks_opts.ivgen_hash_alg,
 997                                                       &local_err);
 998         if (local_err) {
 999             error_propagate(errp, local_err);
1000             goto error;
1001         }
1002     } else {
1003         ivcipheralg = luks_opts.cipher_alg;
1004     }
1005
1006     strcpy(luks->header.cipher_name, cipher_alg);
1007     strcpy(luks->header.cipher_mode, cipher_mode_spec);
1008     strcpy(luks->header.hash_spec, hash_alg);
1009
1010     luks->header.key_bytes = qcrypto_cipher_get_key_len(luks_opts.cipher_alg);
1011     if (luks_opts.cipher_mode == QCRYPTO_CIPHER_MODE_XTS) {
1012         luks->header.key_bytes *= 2;
1013     }
1014
1015     /* Generate the salt used for hashing the master key
1016      * with PBKDF later
1017      */
1018     if (qcrypto_random_bytes(luks->header.master_key_salt,
1019                              QCRYPTO_BLOCK_LUKS_SALT_LEN,
1020                              errp) < 0) {
1021         goto error;
1022     }
1023
1024     /* Generate random master key */
1025     masterkey = g_new0(uint8_t, luks->header.key_bytes);
1026     if (qcrypto_random_bytes(masterkey,
1027                              luks->header.key_bytes, errp) < 0) {
1028         goto error;
1029     }
1030
1031
1032     /* Setup the block device payload encryption objects */
1033     block->cipher = qcrypto_cipher_new(luks_opts.cipher_alg,
1034                                        luks_opts.cipher_mode,
1035                                        masterkey, luks->header.key_bytes,
1036                                        errp);
1037     if (!block->cipher) {
1038         goto error;
1039     }
1040
1041     block->kdfhash = luks_opts.hash_alg;
1042     block->niv = qcrypto_cipher_get_iv_len(luks_opts.cipher_alg,
1043                                            luks_opts.cipher_mode);
1044     block->ivgen = qcrypto_ivgen_new(luks_opts.ivgen_alg,
1045                                      ivcipheralg,
1046                                      luks_opts.ivgen_hash_alg,
1047                                      masterkey, luks->header.key_bytes,
1048                                      errp);
1049
1050     if (!block->ivgen) {
1051         goto error;
1052     }
1053
1054
1055     /* Determine how many iterations we need to hash the master
1056      * key, in order to have 1 second of compute time used
1057      */
1058     iters = qcrypto_pbkdf2_count_iters(luks_opts.hash_alg,
1059                                        masterkey, luks->header.key_bytes,
1060                                        luks->header.master_key_salt,
1061                                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1062                                        QCRYPTO_BLOCK_LUKS_DIGEST_LEN,
1063                                        &local_err);
1064     if (local_err) {
1065         error_propagate(errp, local_err);
1066         goto error;
1067     }
1068
1069     if (iters > (ULLONG_MAX / luks_opts.iter_time)) {
1070         error_setg_errno(errp, ERANGE,
1071                          "PBKDF iterations %llu too large to scale",
1072                          (unsigned long long)iters);
1073         goto error;
1074     }
1075
1076     /* iter_time was in millis, but count_iters reported for secs */
1077     iters = iters * luks_opts.iter_time / 1000;
1078
1079     /* Why /= 8 ?  That matches cryptsetup, but there's no
1080      * explanation why they chose /= 8... Probably so that
1081      * if all 8 keyslots are active we only spend 1 second
1082      * in total time to check all keys */
1083     iters /= 8;
1084     if (iters > UINT32_MAX) {
1085         error_setg_errno(errp, ERANGE,
1086                          "PBKDF iterations %llu larger than %u",
1087                          (unsigned long long)iters, UINT32_MAX);
1088         goto error;
1089     }
1090     iters = MAX(iters, QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS);
1091     luks->header.master_key_iterations = iters;
1092
1093     /* Hash the master key, saving the result in the LUKS
1094      * header. This hash is used when opening the encrypted
1095      * device to verify that the user password unlocked a
1096      * valid master key
1097      */
1098     if (qcrypto_pbkdf2(luks_opts.hash_alg,
1099                        masterkey, luks->header.key_bytes,
1100                        luks->header.master_key_salt,
1101                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1102                        luks->header.master_key_iterations,
1103                        luks->header.master_key_digest,
1104                        QCRYPTO_BLOCK_LUKS_DIGEST_LEN,
1105                        errp) < 0) {
1106         goto error;
1107     }
1108
1109
1110     /* Although LUKS has multiple key slots, we're just going
1111      * to use the first key slot */
1112     splitkeylen = luks->header.key_bytes * QCRYPTO_BLOCK_LUKS_STRIPES;
1113     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1114         luks->header.key_slots[i].active = i == 0 ?
1115             QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED :
1116             QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED;
1117         luks->header.key_slots[i].stripes = QCRYPTO_BLOCK_LUKS_STRIPES;
1118
1119         /* This calculation doesn't match that shown in the spec,
1120          * but instead follows the cryptsetup implementation.
1121          */
1122         luks->header.key_slots[i].key_offset =
1123             (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1124              QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) +
1125             (ROUND_UP(DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE),
1126                       (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1127                        QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) * i);
1128     }
1129
1130     if (qcrypto_random_bytes(luks->header.key_slots[0].salt,
1131                              QCRYPTO_BLOCK_LUKS_SALT_LEN,
1132                              errp) < 0) {
1133         goto error;
1134     }
1135
1136     /* Again we determine how many iterations are required to
1137      * hash the user password while consuming 1 second of compute
1138      * time */
1139     iters = qcrypto_pbkdf2_count_iters(luks_opts.hash_alg,
1140                                        (uint8_t *)password, strlen(password),
1141                                        luks->header.key_slots[0].salt,
1142                                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1143                                        luks->header.key_bytes,
1144                                        &local_err);
1145     if (local_err) {
1146         error_propagate(errp, local_err);
1147         goto error;
1148     }
1149
1150     if (iters > (ULLONG_MAX / luks_opts.iter_time)) {
1151         error_setg_errno(errp, ERANGE,
1152                          "PBKDF iterations %llu too large to scale",
1153                          (unsigned long long)iters);
1154         goto error;
1155     }
1156
1157     /* iter_time was in millis, but count_iters reported for secs */
1158     iters = iters * luks_opts.iter_time / 1000;
1159
1160     if (iters > UINT32_MAX) {
1161         error_setg_errno(errp, ERANGE,
1162                          "PBKDF iterations %llu larger than %u",
1163                          (unsigned long long)iters, UINT32_MAX);
1164         goto error;
1165     }
1166
1167     luks->header.key_slots[0].iterations =
1168         MAX(iters, QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS);
1169
1170
1171     /* Generate a key that we'll use to encrypt the master
1172      * key, from the user's password
1173      */
1174     slotkey = g_new0(uint8_t, luks->header.key_bytes);
1175     if (qcrypto_pbkdf2(luks_opts.hash_alg,
1176                        (uint8_t *)password, strlen(password),
1177                        luks->header.key_slots[0].salt,
1178                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1179                        luks->header.key_slots[0].iterations,
1180                        slotkey, luks->header.key_bytes,
1181                        errp) < 0) {
1182         goto error;
1183     }
1184
1185
1186     /* Setup the encryption objects needed to encrypt the
1187      * master key material
1188      */
1189     cipher = qcrypto_cipher_new(luks_opts.cipher_alg,
1190                                 luks_opts.cipher_mode,
1191                                 slotkey, luks->header.key_bytes,
1192                                 errp);
1193     if (!cipher) {
1194         goto error;
1195     }
1196
1197     ivgen = qcrypto_ivgen_new(luks_opts.ivgen_alg,
1198                               ivcipheralg,
1199                               luks_opts.ivgen_hash_alg,
1200                               slotkey, luks->header.key_bytes,
1201                               errp);
1202     if (!ivgen) {
1203         goto error;
1204     }
1205
1206     /* Before storing the master key, we need to vastly
1207      * increase its size, as protection against forensic
1208      * disk data recovery */
1209     splitkey = g_new0(uint8_t, splitkeylen);
1210
1211     if (qcrypto_afsplit_encode(luks_opts.hash_alg,
1212                                luks->header.key_bytes,
1213                                luks->header.key_slots[0].stripes,
1214                                masterkey,
1215                                splitkey,
1216                                errp) < 0) {
1217         goto error;
1218     }
1219
1220     /* Now we encrypt the split master key with the key generated
1221      * from the user's password, before storing it */
1222     if (qcrypto_block_encrypt_helper(cipher, block->niv, ivgen,
1223                                      QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1224                                      0,
1225                                      splitkey,
1226                                      splitkeylen,
1227                                      errp) < 0) {
1228         goto error;
1229     }
1230
1231
1232     /* The total size of the LUKS headers is the partition header + key
1233      * slot headers, rounded up to the nearest sector, combined with
1234      * the size of each master key material region, also rounded up
1235      * to the nearest sector */
1236     luks->header.payload_offset =
1237         (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1238          QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) +
1239         (ROUND_UP(DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE),
1240                   (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1241                    QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) *
1242          QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS);
1243
1244     block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
1245     block->payload_offset = luks->header.payload_offset *
1246         block->sector_size;
1247
1248     /* Reserve header space to match payload offset */
1249     initfunc(block, block->payload_offset, opaque, &local_err);
1250     if (local_err) {
1251         error_propagate(errp, local_err);
1252         goto error;
1253     }
1254
1255     /* Everything on disk uses Big Endian, so flip header fields
1256      * before writing them */
1257     cpu_to_be16s(&luks->header.version);
1258     cpu_to_be32s(&luks->header.payload_offset);
1259     cpu_to_be32s(&luks->header.key_bytes);
1260     cpu_to_be32s(&luks->header.master_key_iterations);
1261
1262     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1263         cpu_to_be32s(&luks->header.key_slots[i].active);
1264         cpu_to_be32s(&luks->header.key_slots[i].iterations);
1265         cpu_to_be32s(&luks->header.key_slots[i].key_offset);
1266         cpu_to_be32s(&luks->header.key_slots[i].stripes);
1267     }
1268
1269
1270     /* Write out the partition header and key slot headers */
1271     writefunc(block, 0,
1272               (const uint8_t *)&luks->header,
1273               sizeof(luks->header),
1274               opaque,
1275               &local_err);
1276
1277     /* Delay checking local_err until we've byte-swapped */
1278
1279     /* Byte swap the header back to native, in case we need
1280      * to read it again later */
1281     be16_to_cpus(&luks->header.version);
1282     be32_to_cpus(&luks->header.payload_offset);
1283     be32_to_cpus(&luks->header.key_bytes);
1284     be32_to_cpus(&luks->header.master_key_iterations);
1285
1286     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1287         be32_to_cpus(&luks->header.key_slots[i].active);
1288         be32_to_cpus(&luks->header.key_slots[i].iterations);
1289         be32_to_cpus(&luks->header.key_slots[i].key_offset);
1290         be32_to_cpus(&luks->header.key_slots[i].stripes);
1291     }
1292
1293     if (local_err) {
1294         error_propagate(errp, local_err);
1295         goto error;
1296     }
1297
1298     /* Write out the master key material, starting at the
1299      * sector immediately following the partition header. */
1300     if (writefunc(block,
1301                   luks->header.key_slots[0].key_offset *
1302                   QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1303                   splitkey, splitkeylen,
1304                   opaque,
1305                   errp) != splitkeylen) {
1306         goto error;
1307     }
1308
1309     luks->cipher_alg = luks_opts.cipher_alg;
1310     luks->cipher_mode = luks_opts.cipher_mode;
1311     luks->ivgen_alg = luks_opts.ivgen_alg;
1312     luks->ivgen_hash_alg = luks_opts.ivgen_hash_alg;
1313     luks->hash_alg = luks_opts.hash_alg;
1314
1315     memset(masterkey, 0, luks->header.key_bytes);
1316     g_free(masterkey);
1317     memset(slotkey, 0, luks->header.key_bytes);
1318     g_free(slotkey);
1319     g_free(splitkey);
1320     g_free(password);
1321     g_free(cipher_mode_spec);
1322
1323     qcrypto_ivgen_free(ivgen);
1324     qcrypto_cipher_free(cipher);
1325
1326     return 0;
1327
1328  error:
1329     if (masterkey) {
1330         memset(masterkey, 0, luks->header.key_bytes);
1331     }
1332     g_free(masterkey);
1333     if (slotkey) {
1334         memset(slotkey, 0, luks->header.key_bytes);
1335     }
1336     g_free(slotkey);
1337     g_free(splitkey);
1338     g_free(password);
1339     g_free(cipher_mode_spec);
1340
1341     qcrypto_ivgen_free(ivgen);
1342     qcrypto_cipher_free(cipher);
1343
1344     g_free(luks);
1345     return -1;
1346 }
1347
1348
1349 static int qcrypto_block_luks_get_info(QCryptoBlock *block,
1350                                        QCryptoBlockInfo *info,
1351                                        Error **errp)
1352 {
1353     QCryptoBlockLUKS *luks = block->opaque;
1354     QCryptoBlockInfoLUKSSlot *slot;
1355     QCryptoBlockInfoLUKSSlotList *slots = NULL, **prev = &info->u.luks.slots;
1356     size_t i;
1357
1358     info->u.luks.cipher_alg = luks->cipher_alg;
1359     info->u.luks.cipher_mode = luks->cipher_mode;
1360     info->u.luks.ivgen_alg = luks->ivgen_alg;
1361     if (info->u.luks.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
1362         info->u.luks.has_ivgen_hash_alg = true;
1363         info->u.luks.ivgen_hash_alg = luks->ivgen_hash_alg;
1364     }
1365     info->u.luks.hash_alg = luks->hash_alg;
1366     info->u.luks.payload_offset = block->payload_offset;
1367     info->u.luks.master_key_iters = luks->header.master_key_iterations;
1368     info->u.luks.uuid = g_strndup((const char *)luks->header.uuid,
1369                                   sizeof(luks->header.uuid));
1370
1371     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1372         slots = g_new0(QCryptoBlockInfoLUKSSlotList, 1);
1373         *prev = slots;
1374
1375         slots->value = slot = g_new0(QCryptoBlockInfoLUKSSlot, 1);
1376         slot->active = luks->header.key_slots[i].active ==
1377             QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED;
1378         slot->key_offset = luks->header.key_slots[i].key_offset
1379              * QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
1380         if (slot->active) {
1381             slot->has_iters = true;
1382             slot->iters = luks->header.key_slots[i].iterations;
1383             slot->has_stripes = true;
1384             slot->stripes = luks->header.key_slots[i].stripes;
1385         }
1386
1387         prev = &slots->next;
1388     }
1389
1390     return 0;
1391 }
1392
1393
1394 static void qcrypto_block_luks_cleanup(QCryptoBlock *block)
1395 {
1396     g_free(block->opaque);
1397 }
1398
1399
1400 static int
1401 qcrypto_block_luks_decrypt(QCryptoBlock *block,
1402                            uint64_t offset,
1403                            uint8_t *buf,
1404                            size_t len,
1405                            Error **errp)
1406 {
1407     assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE));
1408     assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE));
1409     return qcrypto_block_decrypt_helper(block->cipher,
1410                                         block->niv, block->ivgen,
1411                                         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1412                                         offset, buf, len, errp);
1413 }
1414
1415
1416 static int
1417 qcrypto_block_luks_encrypt(QCryptoBlock *block,
1418                            uint64_t offset,
1419                            uint8_t *buf,
1420                            size_t len,
1421                            Error **errp)
1422 {
1423     assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE));
1424     assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE));
1425     return qcrypto_block_encrypt_helper(block->cipher,
1426                                         block->niv, block->ivgen,
1427                                         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1428                                         offset, buf, len, errp);
1429 }
1430
1431
1432 const QCryptoBlockDriver qcrypto_block_driver_luks = {
1433     .open = qcrypto_block_luks_open,
1434     .create = qcrypto_block_luks_create,
1435     .get_info = qcrypto_block_luks_get_info,
1436     .cleanup = qcrypto_block_luks_cleanup,
1437     .decrypt = qcrypto_block_luks_decrypt,
1438     .encrypt = qcrypto_block_luks_encrypt,
1439     .has_format = qcrypto_block_luks_has_format,
1440 };