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 2.1 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_sector;
 147     /* number of anti-forensic stripes */
 148     uint32_t stripes;
 149 };
 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_sector;
 176
 177     /* Number of key bytes */
 178     uint32_t master_key_len;
 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 };
 195
 196 QEMU_BUILD_BUG_ON(sizeof(struct QCryptoBlockLUKSHeader) != 592);
 197
 198
 199 struct QCryptoBlockLUKS {
 200     QCryptoBlockLUKSHeader header;
 201
 202     /* Main encryption algorithm used for encryption*/
 203     QCryptoCipherAlgorithm cipher_alg;
 204
 205     /* Mode of encryption for the selected encryption algorithm */
 206     QCryptoCipherMode cipher_mode;
 207
 208     /* Initialization vector generation algorithm */
 209     QCryptoIVGenAlgorithm ivgen_alg;
 210
 211     /* Hash algorithm used for IV generation*/
 212     QCryptoHashAlgorithm ivgen_hash_alg;
 213
 214     /*
 215      * Encryption algorithm used for IV generation.
 216      * Usually the same as main encryption algorithm
 217      */
 218     QCryptoCipherAlgorithm ivgen_cipher_alg;
 219
 220     /* Hash algorithm used in pbkdf2 function */
 221     QCryptoHashAlgorithm hash_alg;
 222 };
 223
 224
 225 static int qcrypto_block_luks_cipher_name_lookup(const char *name,
 226                                                  QCryptoCipherMode mode,
 227                                                  uint32_t key_bytes,
 228                                                  Error **errp)
 229 {
 230     const QCryptoBlockLUKSCipherNameMap *map =
 231         qcrypto_block_luks_cipher_name_map;
 232     size_t maplen = G_N_ELEMENTS(qcrypto_block_luks_cipher_name_map);
 233     size_t i, j;
 234
 235     if (mode == QCRYPTO_CIPHER_MODE_XTS) {
 236         key_bytes /= 2;
 237     }
 238
 239     for (i = 0; i < maplen; i++) {
 240         if (!g_str_equal(map[i].name, name)) {
 241             continue;
 242         }
 243         for (j = 0; j < map[i].sizes[j].key_bytes; j++) {
 244             if (map[i].sizes[j].key_bytes == key_bytes) {
 245                 return map[i].sizes[j].id;
 246             }
 247         }
 248     }
 249
 250     error_setg(errp, "Algorithm %s with key size %d bytes not supported",
 251                name, key_bytes);
 252     return 0;
 253 }
 254
 255 static const char *
 256 qcrypto_block_luks_cipher_alg_lookup(QCryptoCipherAlgorithm alg,
 257                                      Error **errp)
 258 {
 259     const QCryptoBlockLUKSCipherNameMap *map =
 260         qcrypto_block_luks_cipher_name_map;
 261     size_t maplen = G_N_ELEMENTS(qcrypto_block_luks_cipher_name_map);
 262     size_t i, j;
 263     for (i = 0; i < maplen; i++) {
 264         for (j = 0; j < map[i].sizes[j].key_bytes; j++) {
 265             if (map[i].sizes[j].id == alg) {
 266                 return map[i].name;
 267             }
 268         }
 269     }
 270
 271     error_setg(errp, "Algorithm '%s' not supported",
 272                QCryptoCipherAlgorithm_str(alg));
 273     return NULL;
 274 }
 275
 276 /* XXX replace with qapi_enum_parse() in future, when we can
 277  * make that function emit a more friendly error message */
 278 static int qcrypto_block_luks_name_lookup(const char *name,
 279                                           const QEnumLookup *map,
 280                                           const char *type,
 281                                           Error **errp)
 282 {
 283     int ret = qapi_enum_parse(map, name, -1, NULL);
 284
 285     if (ret < 0) {
 286         error_setg(errp, "%s %s not supported", type, name);
 287         return 0;
 288     }
 289     return ret;
 290 }
 291
 292 #define qcrypto_block_luks_cipher_mode_lookup(name, errp)               \
 293     qcrypto_block_luks_name_lookup(name,                                \
 294                                    &QCryptoCipherMode_lookup,           \
 295                                    "Cipher mode",                       \
 296                                    errp)
 297
 298 #define qcrypto_block_luks_hash_name_lookup(name, errp)                 \
 299     qcrypto_block_luks_name_lookup(name,                                \
 300                                    &QCryptoHashAlgorithm_lookup,        \
 301                                    "Hash algorithm",                    \
 302                                    errp)
 303
 304 #define qcrypto_block_luks_ivgen_name_lookup(name, errp)                \
 305     qcrypto_block_luks_name_lookup(name,                                \
 306                                    &QCryptoIVGenAlgorithm_lookup,       \
 307                                    "IV generator",                      \
 308                                    errp)
 309
 310
 311 static bool
 312 qcrypto_block_luks_has_format(const uint8_t *buf,
 313                               size_t buf_size)
 314 {
 315     const QCryptoBlockLUKSHeader *luks_header = (const void *)buf;
 316
 317     if (buf_size >= offsetof(QCryptoBlockLUKSHeader, cipher_name) &&
 318         memcmp(luks_header->magic, qcrypto_block_luks_magic,
 319                QCRYPTO_BLOCK_LUKS_MAGIC_LEN) == 0 &&
 320         be16_to_cpu(luks_header->version) == QCRYPTO_BLOCK_LUKS_VERSION) {
 321         return true;
 322     } else {
 323         return false;
 324     }
 325 }
 326
 327
 328 /**
 329  * Deal with a quirk of dm-crypt usage of ESSIV.
 330  *
 331  * When calculating ESSIV IVs, the cipher length used by ESSIV
 332  * may be different from the cipher length used for the block
 333  * encryption, becauses dm-crypt uses the hash digest length
 334  * as the key size. ie, if you have AES 128 as the block cipher
 335  * and SHA 256 as ESSIV hash, then ESSIV will use AES 256 as
 336  * the cipher since that gets a key length matching the digest
 337  * size, not AES 128 with truncated digest as might be imagined
 338  */
 339 static QCryptoCipherAlgorithm
 340 qcrypto_block_luks_essiv_cipher(QCryptoCipherAlgorithm cipher,
 341                                 QCryptoHashAlgorithm hash,
 342                                 Error **errp)
 343 {
 344     size_t digestlen = qcrypto_hash_digest_len(hash);
 345     size_t keylen = qcrypto_cipher_get_key_len(cipher);
 346     if (digestlen == keylen) {
 347         return cipher;
 348     }
 349
 350     switch (cipher) {
 351     case QCRYPTO_CIPHER_ALG_AES_128:
 352     case QCRYPTO_CIPHER_ALG_AES_192:
 353     case QCRYPTO_CIPHER_ALG_AES_256:
 354         if (digestlen == qcrypto_cipher_get_key_len(
 355                 QCRYPTO_CIPHER_ALG_AES_128)) {
 356             return QCRYPTO_CIPHER_ALG_AES_128;
 357         } else if (digestlen == qcrypto_cipher_get_key_len(
 358                        QCRYPTO_CIPHER_ALG_AES_192)) {
 359             return QCRYPTO_CIPHER_ALG_AES_192;
 360         } else if (digestlen == qcrypto_cipher_get_key_len(
 361                        QCRYPTO_CIPHER_ALG_AES_256)) {
 362             return QCRYPTO_CIPHER_ALG_AES_256;
 363         } else {
 364             error_setg(errp, "No AES cipher with key size %zu available",
 365                        digestlen);
 366             return 0;
 367         }
 368         break;
 369     case QCRYPTO_CIPHER_ALG_SERPENT_128:
 370     case QCRYPTO_CIPHER_ALG_SERPENT_192:
 371     case QCRYPTO_CIPHER_ALG_SERPENT_256:
 372         if (digestlen == qcrypto_cipher_get_key_len(
 373                 QCRYPTO_CIPHER_ALG_SERPENT_128)) {
 374             return QCRYPTO_CIPHER_ALG_SERPENT_128;
 375         } else if (digestlen == qcrypto_cipher_get_key_len(
 376                        QCRYPTO_CIPHER_ALG_SERPENT_192)) {
 377             return QCRYPTO_CIPHER_ALG_SERPENT_192;
 378         } else if (digestlen == qcrypto_cipher_get_key_len(
 379                        QCRYPTO_CIPHER_ALG_SERPENT_256)) {
 380             return QCRYPTO_CIPHER_ALG_SERPENT_256;
 381         } else {
 382             error_setg(errp, "No Serpent cipher with key size %zu available",
 383                        digestlen);
 384             return 0;
 385         }
 386         break;
 387     case QCRYPTO_CIPHER_ALG_TWOFISH_128:
 388     case QCRYPTO_CIPHER_ALG_TWOFISH_192:
 389     case QCRYPTO_CIPHER_ALG_TWOFISH_256:
 390         if (digestlen == qcrypto_cipher_get_key_len(
 391                 QCRYPTO_CIPHER_ALG_TWOFISH_128)) {
 392             return QCRYPTO_CIPHER_ALG_TWOFISH_128;
 393         } else if (digestlen == qcrypto_cipher_get_key_len(
 394                        QCRYPTO_CIPHER_ALG_TWOFISH_192)) {
 395             return QCRYPTO_CIPHER_ALG_TWOFISH_192;
 396         } else if (digestlen == qcrypto_cipher_get_key_len(
 397                        QCRYPTO_CIPHER_ALG_TWOFISH_256)) {
 398             return QCRYPTO_CIPHER_ALG_TWOFISH_256;
 399         } else {
 400             error_setg(errp, "No Twofish cipher with key size %zu available",
 401                        digestlen);
 402             return 0;
 403         }
 404         break;
 405     default:
 406         error_setg(errp, "Cipher %s not supported with essiv",
 407                    QCryptoCipherAlgorithm_str(cipher));
 408         return 0;
 409     }
 410 }
 411
 412 /*
 413  * Given a key slot, and user password, this will attempt to unlock
 414  * the master encryption key from the key slot.
 415  *
 416  * Returns:
 417  *    0 if the key slot is disabled, or key could not be decrypted
 418  *      with the provided password
 419  *    1 if the key slot is enabled, and key decrypted successfully
 420  *      with the provided password
 421  *   -1 if a fatal error occurred loading the key
 422  */
 423 static int
 424 qcrypto_block_luks_load_key(QCryptoBlock *block,
 425                             size_t slot_idx,
 426                             const char *password,
 427                             uint8_t *masterkey,
 428                             QCryptoBlockReadFunc readfunc,
 429                             void *opaque,
 430                             Error **errp)
 431 {
 432     QCryptoBlockLUKS *luks = block->opaque;
 433     const QCryptoBlockLUKSKeySlot *slot = &luks->header.key_slots[slot_idx];
 434     g_autofree uint8_t *splitkey = NULL;
 435     size_t splitkeylen;
 436     g_autofree uint8_t *possiblekey = NULL;
 437     ssize_t rv;
 438     g_autoptr(QCryptoCipher) cipher = NULL;
 439     uint8_t keydigest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN];
 440     g_autoptr(QCryptoIVGen) ivgen = NULL;
 441     size_t niv;
 442
 443     if (slot->active != QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED) {
 444         return 0;
 445     }
 446
 447     splitkeylen = luks->header.master_key_len * slot->stripes;
 448     splitkey = g_new0(uint8_t, splitkeylen);
 449     possiblekey = g_new0(uint8_t, luks->header.master_key_len);
 450
 451     /*
 452      * The user password is used to generate a (possible)
 453      * decryption key. This may or may not successfully
 454      * decrypt the master key - we just blindly assume
 455      * the key is correct and validate the results of
 456      * decryption later.
 457      */
 458     if (qcrypto_pbkdf2(luks->hash_alg,
 459                        (const uint8_t *)password, strlen(password),
 460                        slot->salt, QCRYPTO_BLOCK_LUKS_SALT_LEN,
 461                        slot->iterations,
 462                        possiblekey, luks->header.master_key_len,
 463                        errp) < 0) {
 464         return -1;
 465     }
 466
 467     /*
 468      * We need to read the master key material from the
 469      * LUKS key material header. What we're reading is
 470      * not the raw master key, but rather the data after
 471      * it has been passed through AFSplit and the result
 472      * then encrypted.
 473      */
 474     rv = readfunc(block,
 475                   slot->key_offset_sector * QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
 476                   splitkey, splitkeylen,
 477                   opaque,
 478                   errp);
 479     if (rv < 0) {
 480         return -1;
 481     }
 482
 483
 484     /* Setup the cipher/ivgen that we'll use to try to decrypt
 485      * the split master key material */
 486     cipher = qcrypto_cipher_new(luks->cipher_alg,
 487                                 luks->cipher_mode,
 488                                 possiblekey,
 489                                 luks->header.master_key_len,
 490                                 errp);
 491     if (!cipher) {
 492         return -1;
 493     }
 494
 495     niv = qcrypto_cipher_get_iv_len(luks->cipher_alg,
 496                                     luks->cipher_mode);
 497
 498     ivgen = qcrypto_ivgen_new(luks->ivgen_alg,
 499                               luks->ivgen_cipher_alg,
 500                               luks->ivgen_hash_alg,
 501                               possiblekey,
 502                               luks->header.master_key_len,
 503                               errp);
 504     if (!ivgen) {
 505         return -1;
 506     }
 507
 508
 509     /*
 510      * The master key needs to be decrypted in the same
 511      * way that the block device payload will be decrypted
 512      * later. In particular we'll be using the IV generator
 513      * to reset the encryption cipher every time the master
 514      * key crosses a sector boundary.
 515      */
 516     if (qcrypto_block_cipher_decrypt_helper(cipher,
 517                                             niv,
 518                                             ivgen,
 519                                             QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
 520                                             0,
 521                                             splitkey,
 522                                             splitkeylen,
 523                                             errp) < 0) {
 524         return -1;
 525     }
 526
 527     /*
 528      * Now we've decrypted the split master key, join
 529      * it back together to get the actual master key.
 530      */
 531     if (qcrypto_afsplit_decode(luks->hash_alg,
 532                                luks->header.master_key_len,
 533                                slot->stripes,
 534                                splitkey,
 535                                masterkey,
 536                                errp) < 0) {
 537         return -1;
 538     }
 539
 540
 541     /*
 542      * We still don't know that the masterkey we got is valid,
 543      * because we just blindly assumed the user's password
 544      * was correct. This is where we now verify it. We are
 545      * creating a hash of the master key using PBKDF and
 546      * then comparing that to the hash stored in the key slot
 547      * header
 548      */
 549     if (qcrypto_pbkdf2(luks->hash_alg,
 550                        masterkey,
 551                        luks->header.master_key_len,
 552                        luks->header.master_key_salt,
 553                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
 554                        luks->header.master_key_iterations,
 555                        keydigest,
 556                        G_N_ELEMENTS(keydigest),
 557                        errp) < 0) {
 558         return -1;
 559     }
 560
 561     if (memcmp(keydigest, luks->header.master_key_digest,
 562                QCRYPTO_BLOCK_LUKS_DIGEST_LEN) == 0) {
 563         /* Success, we got the right master key */
 564         return 1;
 565     }
 566
 567     /* Fail, user's password was not valid for this key slot,
 568      * tell caller to try another slot */
 569     return 0;
 570 }
 571
 572
 573 /*
 574  * Given a user password, this will iterate over all key
 575  * slots and try to unlock each active key slot using the
 576  * password until it successfully obtains a master key.
 577  *
 578  * Returns 0 if a key was loaded, -1 if no keys could be loaded
 579  */
 580 static int
 581 qcrypto_block_luks_find_key(QCryptoBlock *block,
 582                             const char *password,
 583                             uint8_t *masterkey,
 584                             QCryptoBlockReadFunc readfunc,
 585                             void *opaque,
 586                             Error **errp)
 587 {
 588     size_t i;
 589     int rv;
 590
 591     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
 592         rv = qcrypto_block_luks_load_key(block,
 593                                          i,
 594                                          password,
 595                                          masterkey,
 596                                          readfunc,
 597                                          opaque,
 598                                          errp);
 599         if (rv < 0) {
 600             goto error;
 601         }
 602         if (rv == 1) {
 603             return 0;
 604         }
 605     }
 606
 607     error_setg(errp, "Invalid password, cannot unlock any keyslot");
 608  error:
 609     return -1;
 610 }
 611
 612
 613 static int
 614 qcrypto_block_luks_open(QCryptoBlock *block,
 615                         QCryptoBlockOpenOptions *options,
 616                         const char *optprefix,
 617                         QCryptoBlockReadFunc readfunc,
 618                         void *opaque,
 619                         unsigned int flags,
 620                         size_t n_threads,
 621                         Error **errp)
 622 {
 623     QCryptoBlockLUKS *luks = NULL;
 624     Error *local_err = NULL;
 625     int ret = 0;
 626     size_t i;
 627     ssize_t rv;
 628     g_autofree uint8_t *masterkey = NULL;
 629     char *ivgen_name, *ivhash_name;
 630     g_autofree char *password = NULL;
 631     g_autofree char *cipher_mode = NULL;
 632
 633     if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) {
 634         if (!options->u.luks.key_secret) {
 635             error_setg(errp, "Parameter '%skey-secret' is required for cipher",
 636                        optprefix ? optprefix : "");
 637             return -1;
 638         }
 639         password = qcrypto_secret_lookup_as_utf8(
 640             options->u.luks.key_secret, errp);
 641         if (!password) {
 642             return -1;
 643         }
 644     }
 645
 646     luks = g_new0(QCryptoBlockLUKS, 1);
 647     block->opaque = luks;
 648
 649     /* Read the entire LUKS header, minus the key material from
 650      * the underlying device */
 651     rv = readfunc(block, 0,
 652                   (uint8_t *)&luks->header,
 653                   sizeof(luks->header),
 654                   opaque,
 655                   errp);
 656     if (rv < 0) {
 657         ret = rv;
 658         goto fail;
 659     }
 660
 661     /* The header is always stored in big-endian format, so
 662      * convert everything to native */
 663     be16_to_cpus(&luks->header.version);
 664     be32_to_cpus(&luks->header.payload_offset_sector);
 665     be32_to_cpus(&luks->header.master_key_len);
 666     be32_to_cpus(&luks->header.master_key_iterations);
 667
 668     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
 669         be32_to_cpus(&luks->header.key_slots[i].active);
 670         be32_to_cpus(&luks->header.key_slots[i].iterations);
 671         be32_to_cpus(&luks->header.key_slots[i].key_offset_sector);
 672         be32_to_cpus(&luks->header.key_slots[i].stripes);
 673     }
 674
 675     if (memcmp(luks->header.magic, qcrypto_block_luks_magic,
 676                QCRYPTO_BLOCK_LUKS_MAGIC_LEN) != 0) {
 677         error_setg(errp, "Volume is not in LUKS format");
 678         ret = -EINVAL;
 679         goto fail;
 680     }
 681     if (luks->header.version != QCRYPTO_BLOCK_LUKS_VERSION) {
 682         error_setg(errp, "LUKS version %" PRIu32 " is not supported",
 683                    luks->header.version);
 684         ret = -ENOTSUP;
 685         goto fail;
 686     }
 687
 688     cipher_mode = g_strdup(luks->header.cipher_mode);
 689
 690     /*
 691      * The cipher_mode header contains a string that we have
 692      * to further parse, of the format
 693      *
 694      *    <cipher-mode>-<iv-generator>[:<iv-hash>]
 695      *
 696      * eg  cbc-essiv:sha256, cbc-plain64
 697      */
 698     ivgen_name = strchr(cipher_mode, '-');
 699     if (!ivgen_name) {
 700         ret = -EINVAL;
 701         error_setg(errp, "Unexpected cipher mode string format %s",
 702                    cipher_mode);
 703         goto fail;
 704     }
 705     *ivgen_name = '\0';
 706     ivgen_name++;
 707
 708     ivhash_name = strchr(ivgen_name, ':');
 709     if (!ivhash_name) {
 710         luks->ivgen_hash_alg = 0;
 711     } else {
 712         *ivhash_name = '\0';
 713         ivhash_name++;
 714
 715         luks->ivgen_hash_alg = qcrypto_block_luks_hash_name_lookup(ivhash_name,
 716                                                                    &local_err);
 717         if (local_err) {
 718             ret = -ENOTSUP;
 719             error_propagate(errp, local_err);
 720             goto fail;
 721         }
 722     }
 723
 724     luks->cipher_mode = qcrypto_block_luks_cipher_mode_lookup(cipher_mode,
 725                                                               &local_err);
 726     if (local_err) {
 727         ret = -ENOTSUP;
 728         error_propagate(errp, local_err);
 729         goto fail;
 730     }
 731
 732     luks->cipher_alg =
 733         qcrypto_block_luks_cipher_name_lookup(luks->header.cipher_name,
 734                                               luks->cipher_mode,
 735                                               luks->header.master_key_len,
 736                                               &local_err);
 737     if (local_err) {
 738         ret = -ENOTSUP;
 739         error_propagate(errp, local_err);
 740         goto fail;
 741     }
 742
 743     luks->hash_alg =
 744             qcrypto_block_luks_hash_name_lookup(luks->header.hash_spec,
 745                                                 &local_err);
 746     if (local_err) {
 747         ret = -ENOTSUP;
 748         error_propagate(errp, local_err);
 749         goto fail;
 750     }
 751
 752     luks->ivgen_alg = qcrypto_block_luks_ivgen_name_lookup(ivgen_name,
 753                                                            &local_err);
 754     if (local_err) {
 755         ret = -ENOTSUP;
 756         error_propagate(errp, local_err);
 757         goto fail;
 758     }
 759
 760     if (luks->ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
 761         if (!ivhash_name) {
 762             ret = -EINVAL;
 763             error_setg(errp, "Missing IV generator hash specification");
 764             goto fail;
 765         }
 766         luks->ivgen_cipher_alg =
 767                 qcrypto_block_luks_essiv_cipher(luks->cipher_alg,
 768                                                 luks->ivgen_hash_alg,
 769                                                 &local_err);
 770         if (local_err) {
 771             ret = -ENOTSUP;
 772             error_propagate(errp, local_err);
 773             goto fail;
 774         }
 775     } else {
 776         /* Note we parsed the ivhash_name earlier in the cipher_mode
 777          * spec string even with plain/plain64 ivgens, but we
 778          * will ignore it, since it is irrelevant for these ivgens.
 779          * This is for compat with dm-crypt which will silently
 780          * ignore hash names with these ivgens rather than report
 781          * an error about the invalid usage
 782          */
 783         luks->ivgen_cipher_alg = luks->cipher_alg;
 784     }
 785
 786     if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) {
 787         /* Try to find which key slot our password is valid for
 788          * and unlock the master key from that slot.
 789          */
 790
 791         masterkey = g_new0(uint8_t, luks->header.master_key_len);
 792
 793         if (qcrypto_block_luks_find_key(block,
 794                                         password,
 795                                         masterkey,
 796                                         readfunc, opaque,
 797                                         errp) < 0) {
 798             ret = -EACCES;
 799             goto fail;
 800         }
 801
 802         /* We have a valid master key now, so can setup the
 803          * block device payload decryption objects
 804          */
 805         block->kdfhash = luks->hash_alg;
 806         block->niv = qcrypto_cipher_get_iv_len(luks->cipher_alg,
 807                                                luks->cipher_mode);
 808
 809         block->ivgen = qcrypto_ivgen_new(luks->ivgen_alg,
 810                                          luks->ivgen_cipher_alg,
 811                                          luks->ivgen_hash_alg,
 812                                          masterkey,
 813                                          luks->header.master_key_len,
 814                                          errp);
 815         if (!block->ivgen) {
 816             ret = -ENOTSUP;
 817             goto fail;
 818         }
 819
 820         ret = qcrypto_block_init_cipher(block,
 821                                         luks->cipher_alg,
 822                                         luks->cipher_mode,
 823                                         masterkey,
 824                                         luks->header.master_key_len,
 825                                         n_threads,
 826                                         errp);
 827         if (ret < 0) {
 828             ret = -ENOTSUP;
 829             goto fail;
 830         }
 831     }
 832
 833     block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
 834     block->payload_offset = luks->header.payload_offset_sector *
 835         block->sector_size;
 836
 837
 838     return 0;
 839
 840  fail:
 841     qcrypto_block_free_cipher(block);
 842     qcrypto_ivgen_free(block->ivgen);
 843     g_free(luks);
 844     return ret;
 845 }
 846
 847
 848 static void
 849 qcrypto_block_luks_uuid_gen(uint8_t *uuidstr)
 850 {
 851     QemuUUID uuid;
 852     qemu_uuid_generate(&uuid);
 853     qemu_uuid_unparse(&uuid, (char *)uuidstr);
 854 }
 855
 856 static int
 857 qcrypto_block_luks_create(QCryptoBlock *block,
 858                           QCryptoBlockCreateOptions *options,
 859                           const char *optprefix,
 860                           QCryptoBlockInitFunc initfunc,
 861                           QCryptoBlockWriteFunc writefunc,
 862                           void *opaque,
 863                           Error **errp)
 864 {
 865     QCryptoBlockLUKS *luks;
 866     QCryptoBlockCreateOptionsLUKS luks_opts;
 867     Error *local_err = NULL;
 868     g_autofree uint8_t *masterkey = NULL;
 869     g_autofree uint8_t *slotkey = NULL;
 870     g_autofree uint8_t *splitkey = NULL;
 871     size_t splitkeylen = 0;
 872     size_t i;
 873     g_autoptr(QCryptoCipher) cipher = NULL;
 874     g_autoptr(QCryptoIVGen) ivgen = NULL;
 875     g_autofree char *password = NULL;
 876     const char *cipher_alg;
 877     const char *cipher_mode;
 878     const char *ivgen_alg;
 879     const char *ivgen_hash_alg = NULL;
 880     const char *hash_alg;
 881     g_autofree char *cipher_mode_spec = NULL;
 882     uint64_t iters;
 883
 884     memcpy(&luks_opts, &options->u.luks, sizeof(luks_opts));
 885     if (!luks_opts.has_iter_time) {
 886         luks_opts.iter_time = 2000;
 887     }
 888     if (!luks_opts.has_cipher_alg) {
 889         luks_opts.cipher_alg = QCRYPTO_CIPHER_ALG_AES_256;
 890     }
 891     if (!luks_opts.has_cipher_mode) {
 892         luks_opts.cipher_mode = QCRYPTO_CIPHER_MODE_XTS;
 893     }
 894     if (!luks_opts.has_ivgen_alg) {
 895         luks_opts.ivgen_alg = QCRYPTO_IVGEN_ALG_PLAIN64;
 896     }
 897     if (!luks_opts.has_hash_alg) {
 898         luks_opts.hash_alg = QCRYPTO_HASH_ALG_SHA256;
 899     }
 900     if (luks_opts.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
 901         if (!luks_opts.has_ivgen_hash_alg) {
 902             luks_opts.ivgen_hash_alg = QCRYPTO_HASH_ALG_SHA256;
 903             luks_opts.has_ivgen_hash_alg = true;
 904         }
 905     }
 906
 907     luks = g_new0(QCryptoBlockLUKS, 1);
 908     block->opaque = luks;
 909
 910     luks->cipher_alg = luks_opts.cipher_alg;
 911     luks->cipher_mode = luks_opts.cipher_mode;
 912     luks->ivgen_alg = luks_opts.ivgen_alg;
 913     luks->ivgen_hash_alg = luks_opts.ivgen_hash_alg;
 914     luks->hash_alg = luks_opts.hash_alg;
 915
 916
 917     /* Note we're allowing ivgen_hash_alg to be set even for
 918      * non-essiv iv generators that don't need a hash. It will
 919      * be silently ignored, for compatibility with dm-crypt */
 920
 921     if (!options->u.luks.key_secret) {
 922         error_setg(errp, "Parameter '%skey-secret' is required for cipher",
 923                    optprefix ? optprefix : "");
 924         goto error;
 925     }
 926     password = qcrypto_secret_lookup_as_utf8(luks_opts.key_secret, errp);
 927     if (!password) {
 928         goto error;
 929     }
 930
 931
 932     memcpy(luks->header.magic, qcrypto_block_luks_magic,
 933            QCRYPTO_BLOCK_LUKS_MAGIC_LEN);
 934
 935     /* We populate the header in native endianness initially and
 936      * then convert everything to big endian just before writing
 937      * it out to disk
 938      */
 939     luks->header.version = QCRYPTO_BLOCK_LUKS_VERSION;
 940     qcrypto_block_luks_uuid_gen(luks->header.uuid);
 941
 942     cipher_alg = qcrypto_block_luks_cipher_alg_lookup(luks_opts.cipher_alg,
 943                                                       errp);
 944     if (!cipher_alg) {
 945         goto error;
 946     }
 947
 948     cipher_mode = QCryptoCipherMode_str(luks_opts.cipher_mode);
 949     ivgen_alg = QCryptoIVGenAlgorithm_str(luks_opts.ivgen_alg);
 950     if (luks_opts.has_ivgen_hash_alg) {
 951         ivgen_hash_alg = QCryptoHashAlgorithm_str(luks_opts.ivgen_hash_alg);
 952         cipher_mode_spec = g_strdup_printf("%s-%s:%s", cipher_mode, ivgen_alg,
 953                                            ivgen_hash_alg);
 954     } else {
 955         cipher_mode_spec = g_strdup_printf("%s-%s", cipher_mode, ivgen_alg);
 956     }
 957     hash_alg = QCryptoHashAlgorithm_str(luks_opts.hash_alg);
 958
 959
 960     if (strlen(cipher_alg) >= QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN) {
 961         error_setg(errp, "Cipher name '%s' is too long for LUKS header",
 962                    cipher_alg);
 963         goto error;
 964     }
 965     if (strlen(cipher_mode_spec) >= QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN) {
 966         error_setg(errp, "Cipher mode '%s' is too long for LUKS header",
 967                    cipher_mode_spec);
 968         goto error;
 969     }
 970     if (strlen(hash_alg) >= QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN) {
 971         error_setg(errp, "Hash name '%s' is too long for LUKS header",
 972                    hash_alg);
 973         goto error;
 974     }
 975
 976     if (luks_opts.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
 977         luks->ivgen_cipher_alg =
 978                 qcrypto_block_luks_essiv_cipher(luks_opts.cipher_alg,
 979                                                 luks_opts.ivgen_hash_alg,
 980                                                 &local_err);
 981         if (local_err) {
 982             error_propagate(errp, local_err);
 983             goto error;
 984         }
 985     } else {
 986         luks->ivgen_cipher_alg = luks_opts.cipher_alg;
 987     }
 988
 989     strcpy(luks->header.cipher_name, cipher_alg);
 990     strcpy(luks->header.cipher_mode, cipher_mode_spec);
 991     strcpy(luks->header.hash_spec, hash_alg);
 992
 993     luks->header.master_key_len =
 994         qcrypto_cipher_get_key_len(luks_opts.cipher_alg);
 995
 996     if (luks_opts.cipher_mode == QCRYPTO_CIPHER_MODE_XTS) {
 997         luks->header.master_key_len *= 2;
 998     }
 999
1000     /* Generate the salt used for hashing the master key
1001      * with PBKDF later
1002      */
1003     if (qcrypto_random_bytes(luks->header.master_key_salt,
1004                              QCRYPTO_BLOCK_LUKS_SALT_LEN,
1005                              errp) < 0) {
1006         goto error;
1007     }
1008
1009     /* Generate random master key */
1010     masterkey = g_new0(uint8_t, luks->header.master_key_len);
1011     if (qcrypto_random_bytes(masterkey,
1012                              luks->header.master_key_len, errp) < 0) {
1013         goto error;
1014     }
1015
1016
1017     /* Setup the block device payload encryption objects */
1018     if (qcrypto_block_init_cipher(block, luks_opts.cipher_alg,
1019                                   luks_opts.cipher_mode, masterkey,
1020                                   luks->header.master_key_len, 1, errp) < 0) {
1021         goto error;
1022     }
1023
1024     block->kdfhash = luks_opts.hash_alg;
1025     block->niv = qcrypto_cipher_get_iv_len(luks_opts.cipher_alg,
1026                                            luks_opts.cipher_mode);
1027     block->ivgen = qcrypto_ivgen_new(luks_opts.ivgen_alg,
1028                                      luks->ivgen_cipher_alg,
1029                                      luks_opts.ivgen_hash_alg,
1030                                      masterkey, luks->header.master_key_len,
1031                                      errp);
1032
1033     if (!block->ivgen) {
1034         goto error;
1035     }
1036
1037
1038     /* Determine how many iterations we need to hash the master
1039      * key, in order to have 1 second of compute time used
1040      */
1041     iters = qcrypto_pbkdf2_count_iters(luks_opts.hash_alg,
1042                                        masterkey, luks->header.master_key_len,
1043                                        luks->header.master_key_salt,
1044                                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1045                                        QCRYPTO_BLOCK_LUKS_DIGEST_LEN,
1046                                        &local_err);
1047     if (local_err) {
1048         error_propagate(errp, local_err);
1049         goto error;
1050     }
1051
1052     if (iters > (ULLONG_MAX / luks_opts.iter_time)) {
1053         error_setg_errno(errp, ERANGE,
1054                          "PBKDF iterations %llu too large to scale",
1055                          (unsigned long long)iters);
1056         goto error;
1057     }
1058
1059     /* iter_time was in millis, but count_iters reported for secs */
1060     iters = iters * luks_opts.iter_time / 1000;
1061
1062     /* Why /= 8 ?  That matches cryptsetup, but there's no
1063      * explanation why they chose /= 8... Probably so that
1064      * if all 8 keyslots are active we only spend 1 second
1065      * in total time to check all keys */
1066     iters /= 8;
1067     if (iters > UINT32_MAX) {
1068         error_setg_errno(errp, ERANGE,
1069                          "PBKDF iterations %llu larger than %u",
1070                          (unsigned long long)iters, UINT32_MAX);
1071         goto error;
1072     }
1073     iters = MAX(iters, QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS);
1074     luks->header.master_key_iterations = iters;
1075
1076     /* Hash the master key, saving the result in the LUKS
1077      * header. This hash is used when opening the encrypted
1078      * device to verify that the user password unlocked a
1079      * valid master key
1080      */
1081     if (qcrypto_pbkdf2(luks_opts.hash_alg,
1082                        masterkey, luks->header.master_key_len,
1083                        luks->header.master_key_salt,
1084                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1085                        luks->header.master_key_iterations,
1086                        luks->header.master_key_digest,
1087                        QCRYPTO_BLOCK_LUKS_DIGEST_LEN,
1088                        errp) < 0) {
1089         goto error;
1090     }
1091
1092
1093     /* Although LUKS has multiple key slots, we're just going
1094      * to use the first key slot */
1095     splitkeylen = luks->header.master_key_len * QCRYPTO_BLOCK_LUKS_STRIPES;
1096     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1097         luks->header.key_slots[i].active = i == 0 ?
1098             QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED :
1099             QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED;
1100         luks->header.key_slots[i].stripes = QCRYPTO_BLOCK_LUKS_STRIPES;
1101
1102         /* This calculation doesn't match that shown in the spec,
1103          * but instead follows the cryptsetup implementation.
1104          */
1105         luks->header.key_slots[i].key_offset_sector =
1106             (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1107              QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) +
1108             (ROUND_UP(DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE),
1109                       (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1110                        QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) * i);
1111     }
1112
1113     if (qcrypto_random_bytes(luks->header.key_slots[0].salt,
1114                              QCRYPTO_BLOCK_LUKS_SALT_LEN,
1115                              errp) < 0) {
1116         goto error;
1117     }
1118
1119     /* Again we determine how many iterations are required to
1120      * hash the user password while consuming 1 second of compute
1121      * time */
1122     iters = qcrypto_pbkdf2_count_iters(luks_opts.hash_alg,
1123                                        (uint8_t *)password, strlen(password),
1124                                        luks->header.key_slots[0].salt,
1125                                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1126                                        luks->header.master_key_len,
1127                                        &local_err);
1128     if (local_err) {
1129         error_propagate(errp, local_err);
1130         goto error;
1131     }
1132
1133     if (iters > (ULLONG_MAX / luks_opts.iter_time)) {
1134         error_setg_errno(errp, ERANGE,
1135                          "PBKDF iterations %llu too large to scale",
1136                          (unsigned long long)iters);
1137         goto error;
1138     }
1139
1140     /* iter_time was in millis, but count_iters reported for secs */
1141     iters = iters * luks_opts.iter_time / 1000;
1142
1143     if (iters > UINT32_MAX) {
1144         error_setg_errno(errp, ERANGE,
1145                          "PBKDF iterations %llu larger than %u",
1146                          (unsigned long long)iters, UINT32_MAX);
1147         goto error;
1148     }
1149
1150     luks->header.key_slots[0].iterations =
1151         MAX(iters, QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS);
1152
1153
1154     /* Generate a key that we'll use to encrypt the master
1155      * key, from the user's password
1156      */
1157     slotkey = g_new0(uint8_t, luks->header.master_key_len);
1158     if (qcrypto_pbkdf2(luks_opts.hash_alg,
1159                        (uint8_t *)password, strlen(password),
1160                        luks->header.key_slots[0].salt,
1161                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1162                        luks->header.key_slots[0].iterations,
1163                        slotkey, luks->header.master_key_len,
1164                        errp) < 0) {
1165         goto error;
1166     }
1167
1168
1169     /* Setup the encryption objects needed to encrypt the
1170      * master key material
1171      */
1172     cipher = qcrypto_cipher_new(luks_opts.cipher_alg,
1173                                 luks_opts.cipher_mode,
1174                                 slotkey, luks->header.master_key_len,
1175                                 errp);
1176     if (!cipher) {
1177         goto error;
1178     }
1179
1180     ivgen = qcrypto_ivgen_new(luks_opts.ivgen_alg,
1181                               luks->ivgen_cipher_alg,
1182                               luks_opts.ivgen_hash_alg,
1183                               slotkey, luks->header.master_key_len,
1184                               errp);
1185     if (!ivgen) {
1186         goto error;
1187     }
1188
1189     /* Before storing the master key, we need to vastly
1190      * increase its size, as protection against forensic
1191      * disk data recovery */
1192     splitkey = g_new0(uint8_t, splitkeylen);
1193
1194     if (qcrypto_afsplit_encode(luks_opts.hash_alg,
1195                                luks->header.master_key_len,
1196                                luks->header.key_slots[0].stripes,
1197                                masterkey,
1198                                splitkey,
1199                                errp) < 0) {
1200         goto error;
1201     }
1202
1203     /* Now we encrypt the split master key with the key generated
1204      * from the user's password, before storing it */
1205     if (qcrypto_block_cipher_encrypt_helper(cipher, block->niv, ivgen,
1206                                             QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1207                                             0,
1208                                             splitkey,
1209                                             splitkeylen,
1210                                             errp) < 0) {
1211         goto error;
1212     }
1213
1214
1215     /* The total size of the LUKS headers is the partition header + key
1216      * slot headers, rounded up to the nearest sector, combined with
1217      * the size of each master key material region, also rounded up
1218      * to the nearest sector */
1219     luks->header.payload_offset_sector =
1220         (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1221          QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) +
1222         (ROUND_UP(DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE),
1223                   (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1224                    QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) *
1225          QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS);
1226
1227     block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
1228     block->payload_offset = luks->header.payload_offset_sector *
1229         block->sector_size;
1230
1231     /* Reserve header space to match payload offset */
1232     initfunc(block, block->payload_offset, opaque, &local_err);
1233     if (local_err) {
1234         error_propagate(errp, local_err);
1235         goto error;
1236     }
1237
1238     /* Everything on disk uses Big Endian, so flip header fields
1239      * before writing them */
1240     cpu_to_be16s(&luks->header.version);
1241     cpu_to_be32s(&luks->header.payload_offset_sector);
1242     cpu_to_be32s(&luks->header.master_key_len);
1243     cpu_to_be32s(&luks->header.master_key_iterations);
1244
1245     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1246         cpu_to_be32s(&luks->header.key_slots[i].active);
1247         cpu_to_be32s(&luks->header.key_slots[i].iterations);
1248         cpu_to_be32s(&luks->header.key_slots[i].key_offset_sector);
1249         cpu_to_be32s(&luks->header.key_slots[i].stripes);
1250     }
1251
1252
1253     /* Write out the partition header and key slot headers */
1254     writefunc(block, 0,
1255               (const uint8_t *)&luks->header,
1256               sizeof(luks->header),
1257               opaque,
1258               &local_err);
1259
1260     /* Delay checking local_err until we've byte-swapped */
1261
1262     /* Byte swap the header back to native, in case we need
1263      * to read it again later */
1264     be16_to_cpus(&luks->header.version);
1265     be32_to_cpus(&luks->header.payload_offset_sector);
1266     be32_to_cpus(&luks->header.master_key_len);
1267     be32_to_cpus(&luks->header.master_key_iterations);
1268
1269     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1270         be32_to_cpus(&luks->header.key_slots[i].active);
1271         be32_to_cpus(&luks->header.key_slots[i].iterations);
1272         be32_to_cpus(&luks->header.key_slots[i].key_offset_sector);
1273         be32_to_cpus(&luks->header.key_slots[i].stripes);
1274     }
1275
1276     if (local_err) {
1277         error_propagate(errp, local_err);
1278         goto error;
1279     }
1280
1281     /* Write out the master key material, starting at the
1282      * sector immediately following the partition header. */
1283     if (writefunc(block,
1284                   luks->header.key_slots[0].key_offset_sector *
1285                   QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1286                   splitkey, splitkeylen,
1287                   opaque,
1288                   errp) != splitkeylen) {
1289         goto error;
1290     }
1291
1292     memset(masterkey, 0, luks->header.master_key_len);
1293     memset(slotkey, 0, luks->header.master_key_len);
1294
1295     return 0;
1296
1297  error:
1298     if (masterkey) {
1299         memset(masterkey, 0, luks->header.master_key_len);
1300     }
1301     if (slotkey) {
1302         memset(slotkey, 0, luks->header.master_key_len);
1303     }
1304
1305     qcrypto_block_free_cipher(block);
1306     qcrypto_ivgen_free(block->ivgen);
1307
1308     g_free(luks);
1309     return -1;
1310 }
1311
1312
1313 static int qcrypto_block_luks_get_info(QCryptoBlock *block,
1314                                        QCryptoBlockInfo *info,
1315                                        Error **errp)
1316 {
1317     QCryptoBlockLUKS *luks = block->opaque;
1318     QCryptoBlockInfoLUKSSlot *slot;
1319     QCryptoBlockInfoLUKSSlotList *slots = NULL, **prev = &info->u.luks.slots;
1320     size_t i;
1321
1322     info->u.luks.cipher_alg = luks->cipher_alg;
1323     info->u.luks.cipher_mode = luks->cipher_mode;
1324     info->u.luks.ivgen_alg = luks->ivgen_alg;
1325     if (info->u.luks.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
1326         info->u.luks.has_ivgen_hash_alg = true;
1327         info->u.luks.ivgen_hash_alg = luks->ivgen_hash_alg;
1328     }
1329     info->u.luks.hash_alg = luks->hash_alg;
1330     info->u.luks.payload_offset = block->payload_offset;
1331     info->u.luks.master_key_iters = luks->header.master_key_iterations;
1332     info->u.luks.uuid = g_strndup((const char *)luks->header.uuid,
1333                                   sizeof(luks->header.uuid));
1334
1335     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1336         slots = g_new0(QCryptoBlockInfoLUKSSlotList, 1);
1337         *prev = slots;
1338
1339         slots->value = slot = g_new0(QCryptoBlockInfoLUKSSlot, 1);
1340         slot->active = luks->header.key_slots[i].active ==
1341             QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED;
1342         slot->key_offset = luks->header.key_slots[i].key_offset_sector
1343              * QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
1344         if (slot->active) {
1345             slot->has_iters = true;
1346             slot->iters = luks->header.key_slots[i].iterations;
1347             slot->has_stripes = true;
1348             slot->stripes = luks->header.key_slots[i].stripes;
1349         }
1350
1351         prev = &slots->next;
1352     }
1353
1354     return 0;
1355 }
1356
1357
1358 static void qcrypto_block_luks_cleanup(QCryptoBlock *block)
1359 {
1360     g_free(block->opaque);
1361 }
1362
1363
1364 static int
1365 qcrypto_block_luks_decrypt(QCryptoBlock *block,
1366                            uint64_t offset,
1367                            uint8_t *buf,
1368                            size_t len,
1369                            Error **errp)
1370 {
1371     assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE));
1372     assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE));
1373     return qcrypto_block_decrypt_helper(block,
1374                                         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1375                                         offset, buf, len, errp);
1376 }
1377
1378
1379 static int
1380 qcrypto_block_luks_encrypt(QCryptoBlock *block,
1381                            uint64_t offset,
1382                            uint8_t *buf,
1383                            size_t len,
1384                            Error **errp)
1385 {
1386     assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE));
1387     assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE));
1388     return qcrypto_block_encrypt_helper(block,
1389                                         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1390                                         offset, buf, len, errp);
1391 }
1392
1393
1394 const QCryptoBlockDriver qcrypto_block_driver_luks = {
1395     .open = qcrypto_block_luks_open,
1396     .create = qcrypto_block_luks_create,
1397     .get_info = qcrypto_block_luks_get_info,
1398     .cleanup = qcrypto_block_luks_cleanup,
1399     .decrypt = qcrypto_block_luks_decrypt,
1400     .encrypt = qcrypto_block_luks_encrypt,
1401     .has_format = qcrypto_block_luks_has_format,
1402 };