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  * Stores the main LUKS header, taking care of endianess
 414  */
 415 static int
 416 qcrypto_block_luks_store_header(QCryptoBlock *block,
 417                                 QCryptoBlockWriteFunc writefunc,
 418                                 void *opaque,
 419                                 Error **errp)
 420 {
 421     const QCryptoBlockLUKS *luks = block->opaque;
 422     Error *local_err = NULL;
 423     size_t i;
 424     g_autofree QCryptoBlockLUKSHeader *hdr_copy = NULL;
 425
 426     /* Create a copy of the header */
 427     hdr_copy = g_new0(QCryptoBlockLUKSHeader, 1);
 428     memcpy(hdr_copy, &luks->header, sizeof(QCryptoBlockLUKSHeader));
 429
 430     /*
 431      * Everything on disk uses Big Endian (tm), so flip header fields
 432      * before writing them
 433      */
 434     cpu_to_be16s(&hdr_copy->version);
 435     cpu_to_be32s(&hdr_copy->payload_offset_sector);
 436     cpu_to_be32s(&hdr_copy->master_key_len);
 437     cpu_to_be32s(&hdr_copy->master_key_iterations);
 438
 439     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
 440         cpu_to_be32s(&hdr_copy->key_slots[i].active);
 441         cpu_to_be32s(&hdr_copy->key_slots[i].iterations);
 442         cpu_to_be32s(&hdr_copy->key_slots[i].key_offset_sector);
 443         cpu_to_be32s(&hdr_copy->key_slots[i].stripes);
 444     }
 445
 446     /* Write out the partition header and key slot headers */
 447     writefunc(block, 0, (const uint8_t *)hdr_copy, sizeof(*hdr_copy),
 448               opaque, &local_err);
 449
 450     if (local_err) {
 451         error_propagate(errp, local_err);
 452         return -1;
 453     }
 454     return 0;
 455 }
 456
 457 /*
 458  * Loads the main LUKS header,and byteswaps it to native endianess
 459  * And run basic sanity checks on it
 460  */
 461 static int
 462 qcrypto_block_luks_load_header(QCryptoBlock *block,
 463                                 QCryptoBlockReadFunc readfunc,
 464                                 void *opaque,
 465                                 Error **errp)
 466 {
 467     ssize_t rv;
 468     size_t i;
 469     QCryptoBlockLUKS *luks = block->opaque;
 470
 471     /*
 472      * Read the entire LUKS header, minus the key material from
 473      * the underlying device
 474      */
 475     rv = readfunc(block, 0,
 476                   (uint8_t *)&luks->header,
 477                   sizeof(luks->header),
 478                   opaque,
 479                   errp);
 480     if (rv < 0) {
 481         return rv;
 482     }
 483
 484     /*
 485      * The header is always stored in big-endian format, so
 486      * convert everything to native
 487      */
 488     be16_to_cpus(&luks->header.version);
 489     be32_to_cpus(&luks->header.payload_offset_sector);
 490     be32_to_cpus(&luks->header.master_key_len);
 491     be32_to_cpus(&luks->header.master_key_iterations);
 492
 493     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
 494         be32_to_cpus(&luks->header.key_slots[i].active);
 495         be32_to_cpus(&luks->header.key_slots[i].iterations);
 496         be32_to_cpus(&luks->header.key_slots[i].key_offset_sector);
 497         be32_to_cpus(&luks->header.key_slots[i].stripes);
 498     }
 499
 500     return 0;
 501 }
 502
 503 /*
 504  * Does basic sanity checks on the LUKS header
 505  */
 506 static int
 507 qcrypto_block_luks_check_header(const QCryptoBlockLUKS *luks, Error **errp)
 508 {
 509     if (memcmp(luks->header.magic, qcrypto_block_luks_magic,
 510                QCRYPTO_BLOCK_LUKS_MAGIC_LEN) != 0) {
 511         error_setg(errp, "Volume is not in LUKS format");
 512         return -1;
 513     }
 514
 515     if (luks->header.version != QCRYPTO_BLOCK_LUKS_VERSION) {
 516         error_setg(errp, "LUKS version %" PRIu32 " is not supported",
 517                    luks->header.version);
 518         return -1;
 519     }
 520     return 0;
 521 }
 522
 523 /*
 524  * Parses the crypto parameters that are stored in the LUKS header
 525  */
 526
 527 static int
 528 qcrypto_block_luks_parse_header(QCryptoBlockLUKS *luks, Error **errp)
 529 {
 530     g_autofree char *cipher_mode = g_strdup(luks->header.cipher_mode);
 531     char *ivgen_name, *ivhash_name;
 532     Error *local_err = NULL;
 533
 534     /*
 535      * The cipher_mode header contains a string that we have
 536      * to further parse, of the format
 537      *
 538      *    <cipher-mode>-<iv-generator>[:<iv-hash>]
 539      *
 540      * eg  cbc-essiv:sha256, cbc-plain64
 541      */
 542     ivgen_name = strchr(cipher_mode, '-');
 543     if (!ivgen_name) {
 544         error_setg(errp, "Unexpected cipher mode string format %s",
 545                    luks->header.cipher_mode);
 546         return -1;
 547     }
 548     *ivgen_name = '\0';
 549     ivgen_name++;
 550
 551     ivhash_name = strchr(ivgen_name, ':');
 552     if (!ivhash_name) {
 553         luks->ivgen_hash_alg = 0;
 554     } else {
 555         *ivhash_name = '\0';
 556         ivhash_name++;
 557
 558         luks->ivgen_hash_alg = qcrypto_block_luks_hash_name_lookup(ivhash_name,
 559                                                                    &local_err);
 560         if (local_err) {
 561             error_propagate(errp, local_err);
 562             return -1;
 563         }
 564     }
 565
 566     luks->cipher_mode = qcrypto_block_luks_cipher_mode_lookup(cipher_mode,
 567                                                               &local_err);
 568     if (local_err) {
 569         error_propagate(errp, local_err);
 570         return -1;
 571     }
 572
 573     luks->cipher_alg =
 574             qcrypto_block_luks_cipher_name_lookup(luks->header.cipher_name,
 575                                                   luks->cipher_mode,
 576                                                   luks->header.master_key_len,
 577                                                   &local_err);
 578     if (local_err) {
 579         error_propagate(errp, local_err);
 580         return -1;
 581     }
 582
 583     luks->hash_alg =
 584             qcrypto_block_luks_hash_name_lookup(luks->header.hash_spec,
 585                                                 &local_err);
 586     if (local_err) {
 587         error_propagate(errp, local_err);
 588         return -1;
 589     }
 590
 591     luks->ivgen_alg = qcrypto_block_luks_ivgen_name_lookup(ivgen_name,
 592                                                            &local_err);
 593     if (local_err) {
 594         error_propagate(errp, local_err);
 595         return -1;
 596     }
 597
 598     if (luks->ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
 599         if (!ivhash_name) {
 600             error_setg(errp, "Missing IV generator hash specification");
 601             return -1;
 602         }
 603         luks->ivgen_cipher_alg =
 604                 qcrypto_block_luks_essiv_cipher(luks->cipher_alg,
 605                                                 luks->ivgen_hash_alg,
 606                                                 &local_err);
 607         if (local_err) {
 608             error_propagate(errp, local_err);
 609             return -1;
 610         }
 611     } else {
 612
 613         /*
 614          * Note we parsed the ivhash_name earlier in the cipher_mode
 615          * spec string even with plain/plain64 ivgens, but we
 616          * will ignore it, since it is irrelevant for these ivgens.
 617          * This is for compat with dm-crypt which will silently
 618          * ignore hash names with these ivgens rather than report
 619          * an error about the invalid usage
 620          */
 621         luks->ivgen_cipher_alg = luks->cipher_alg;
 622     }
 623     return 0;
 624 }
 625
 626 /*
 627  * Given a key slot, and user password, this will attempt to unlock
 628  * the master encryption key from the key slot.
 629  *
 630  * Returns:
 631  *    0 if the key slot is disabled, or key could not be decrypted
 632  *      with the provided password
 633  *    1 if the key slot is enabled, and key decrypted successfully
 634  *      with the provided password
 635  *   -1 if a fatal error occurred loading the key
 636  */
 637 static int
 638 qcrypto_block_luks_load_key(QCryptoBlock *block,
 639                             size_t slot_idx,
 640                             const char *password,
 641                             uint8_t *masterkey,
 642                             QCryptoBlockReadFunc readfunc,
 643                             void *opaque,
 644                             Error **errp)
 645 {
 646     QCryptoBlockLUKS *luks = block->opaque;
 647     const QCryptoBlockLUKSKeySlot *slot = &luks->header.key_slots[slot_idx];
 648     g_autofree uint8_t *splitkey = NULL;
 649     size_t splitkeylen;
 650     g_autofree uint8_t *possiblekey = NULL;
 651     ssize_t rv;
 652     g_autoptr(QCryptoCipher) cipher = NULL;
 653     uint8_t keydigest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN];
 654     g_autoptr(QCryptoIVGen) ivgen = NULL;
 655     size_t niv;
 656
 657     if (slot->active != QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED) {
 658         return 0;
 659     }
 660
 661     splitkeylen = luks->header.master_key_len * slot->stripes;
 662     splitkey = g_new0(uint8_t, splitkeylen);
 663     possiblekey = g_new0(uint8_t, luks->header.master_key_len);
 664
 665     /*
 666      * The user password is used to generate a (possible)
 667      * decryption key. This may or may not successfully
 668      * decrypt the master key - we just blindly assume
 669      * the key is correct and validate the results of
 670      * decryption later.
 671      */
 672     if (qcrypto_pbkdf2(luks->hash_alg,
 673                        (const uint8_t *)password, strlen(password),
 674                        slot->salt, QCRYPTO_BLOCK_LUKS_SALT_LEN,
 675                        slot->iterations,
 676                        possiblekey, luks->header.master_key_len,
 677                        errp) < 0) {
 678         return -1;
 679     }
 680
 681     /*
 682      * We need to read the master key material from the
 683      * LUKS key material header. What we're reading is
 684      * not the raw master key, but rather the data after
 685      * it has been passed through AFSplit and the result
 686      * then encrypted.
 687      */
 688     rv = readfunc(block,
 689                   slot->key_offset_sector * QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
 690                   splitkey, splitkeylen,
 691                   opaque,
 692                   errp);
 693     if (rv < 0) {
 694         return -1;
 695     }
 696
 697
 698     /* Setup the cipher/ivgen that we'll use to try to decrypt
 699      * the split master key material */
 700     cipher = qcrypto_cipher_new(luks->cipher_alg,
 701                                 luks->cipher_mode,
 702                                 possiblekey,
 703                                 luks->header.master_key_len,
 704                                 errp);
 705     if (!cipher) {
 706         return -1;
 707     }
 708
 709     niv = qcrypto_cipher_get_iv_len(luks->cipher_alg,
 710                                     luks->cipher_mode);
 711
 712     ivgen = qcrypto_ivgen_new(luks->ivgen_alg,
 713                               luks->ivgen_cipher_alg,
 714                               luks->ivgen_hash_alg,
 715                               possiblekey,
 716                               luks->header.master_key_len,
 717                               errp);
 718     if (!ivgen) {
 719         return -1;
 720     }
 721
 722
 723     /*
 724      * The master key needs to be decrypted in the same
 725      * way that the block device payload will be decrypted
 726      * later. In particular we'll be using the IV generator
 727      * to reset the encryption cipher every time the master
 728      * key crosses a sector boundary.
 729      */
 730     if (qcrypto_block_cipher_decrypt_helper(cipher,
 731                                             niv,
 732                                             ivgen,
 733                                             QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
 734                                             0,
 735                                             splitkey,
 736                                             splitkeylen,
 737                                             errp) < 0) {
 738         return -1;
 739     }
 740
 741     /*
 742      * Now we've decrypted the split master key, join
 743      * it back together to get the actual master key.
 744      */
 745     if (qcrypto_afsplit_decode(luks->hash_alg,
 746                                luks->header.master_key_len,
 747                                slot->stripes,
 748                                splitkey,
 749                                masterkey,
 750                                errp) < 0) {
 751         return -1;
 752     }
 753
 754
 755     /*
 756      * We still don't know that the masterkey we got is valid,
 757      * because we just blindly assumed the user's password
 758      * was correct. This is where we now verify it. We are
 759      * creating a hash of the master key using PBKDF and
 760      * then comparing that to the hash stored in the key slot
 761      * header
 762      */
 763     if (qcrypto_pbkdf2(luks->hash_alg,
 764                        masterkey,
 765                        luks->header.master_key_len,
 766                        luks->header.master_key_salt,
 767                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
 768                        luks->header.master_key_iterations,
 769                        keydigest,
 770                        G_N_ELEMENTS(keydigest),
 771                        errp) < 0) {
 772         return -1;
 773     }
 774
 775     if (memcmp(keydigest, luks->header.master_key_digest,
 776                QCRYPTO_BLOCK_LUKS_DIGEST_LEN) == 0) {
 777         /* Success, we got the right master key */
 778         return 1;
 779     }
 780
 781     /* Fail, user's password was not valid for this key slot,
 782      * tell caller to try another slot */
 783     return 0;
 784 }
 785
 786
 787 /*
 788  * Given a user password, this will iterate over all key
 789  * slots and try to unlock each active key slot using the
 790  * password until it successfully obtains a master key.
 791  *
 792  * Returns 0 if a key was loaded, -1 if no keys could be loaded
 793  */
 794 static int
 795 qcrypto_block_luks_find_key(QCryptoBlock *block,
 796                             const char *password,
 797                             uint8_t *masterkey,
 798                             QCryptoBlockReadFunc readfunc,
 799                             void *opaque,
 800                             Error **errp)
 801 {
 802     size_t i;
 803     int rv;
 804
 805     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
 806         rv = qcrypto_block_luks_load_key(block,
 807                                          i,
 808                                          password,
 809                                          masterkey,
 810                                          readfunc,
 811                                          opaque,
 812                                          errp);
 813         if (rv < 0) {
 814             goto error;
 815         }
 816         if (rv == 1) {
 817             return 0;
 818         }
 819     }
 820
 821     error_setg(errp, "Invalid password, cannot unlock any keyslot");
 822  error:
 823     return -1;
 824 }
 825
 826
 827 static int
 828 qcrypto_block_luks_open(QCryptoBlock *block,
 829                         QCryptoBlockOpenOptions *options,
 830                         const char *optprefix,
 831                         QCryptoBlockReadFunc readfunc,
 832                         void *opaque,
 833                         unsigned int flags,
 834                         size_t n_threads,
 835                         Error **errp)
 836 {
 837     QCryptoBlockLUKS *luks = NULL;
 838     g_autofree uint8_t *masterkey = NULL;
 839     g_autofree char *password = NULL;
 840
 841     if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) {
 842         if (!options->u.luks.key_secret) {
 843             error_setg(errp, "Parameter '%skey-secret' is required for cipher",
 844                        optprefix ? optprefix : "");
 845             return -1;
 846         }
 847         password = qcrypto_secret_lookup_as_utf8(
 848             options->u.luks.key_secret, errp);
 849         if (!password) {
 850             return -1;
 851         }
 852     }
 853
 854     luks = g_new0(QCryptoBlockLUKS, 1);
 855     block->opaque = luks;
 856
 857     if (qcrypto_block_luks_load_header(block, readfunc, opaque, errp) < 0) {
 858         goto fail;
 859     }
 860
 861     if (qcrypto_block_luks_check_header(luks, errp) < 0) {
 862         goto fail;
 863     }
 864
 865     if (qcrypto_block_luks_parse_header(luks, errp) < 0) {
 866         goto fail;
 867     }
 868
 869     if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) {
 870         /* Try to find which key slot our password is valid for
 871          * and unlock the master key from that slot.
 872          */
 873
 874         masterkey = g_new0(uint8_t, luks->header.master_key_len);
 875
 876         if (qcrypto_block_luks_find_key(block,
 877                                         password,
 878                                         masterkey,
 879                                         readfunc, opaque,
 880                                         errp) < 0) {
 881             goto fail;
 882         }
 883
 884         /* We have a valid master key now, so can setup the
 885          * block device payload decryption objects
 886          */
 887         block->kdfhash = luks->hash_alg;
 888         block->niv = qcrypto_cipher_get_iv_len(luks->cipher_alg,
 889                                                luks->cipher_mode);
 890
 891         block->ivgen = qcrypto_ivgen_new(luks->ivgen_alg,
 892                                          luks->ivgen_cipher_alg,
 893                                          luks->ivgen_hash_alg,
 894                                          masterkey,
 895                                          luks->header.master_key_len,
 896                                          errp);
 897         if (!block->ivgen) {
 898             goto fail;
 899         }
 900
 901         if (qcrypto_block_init_cipher(block,
 902                                       luks->cipher_alg,
 903                                       luks->cipher_mode,
 904                                       masterkey,
 905                                       luks->header.master_key_len,
 906                                       n_threads,
 907                                       errp) < 0) {
 908             goto fail;
 909         }
 910     }
 911
 912     block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
 913     block->payload_offset = luks->header.payload_offset_sector *
 914         block->sector_size;
 915
 916     return 0;
 917
 918  fail:
 919     qcrypto_block_free_cipher(block);
 920     qcrypto_ivgen_free(block->ivgen);
 921     g_free(luks);
 922     return -1;
 923 }
 924
 925
 926 static void
 927 qcrypto_block_luks_uuid_gen(uint8_t *uuidstr)
 928 {
 929     QemuUUID uuid;
 930     qemu_uuid_generate(&uuid);
 931     qemu_uuid_unparse(&uuid, (char *)uuidstr);
 932 }
 933
 934 static int
 935 qcrypto_block_luks_create(QCryptoBlock *block,
 936                           QCryptoBlockCreateOptions *options,
 937                           const char *optprefix,
 938                           QCryptoBlockInitFunc initfunc,
 939                           QCryptoBlockWriteFunc writefunc,
 940                           void *opaque,
 941                           Error **errp)
 942 {
 943     QCryptoBlockLUKS *luks;
 944     QCryptoBlockCreateOptionsLUKS luks_opts;
 945     Error *local_err = NULL;
 946     g_autofree uint8_t *masterkey = NULL;
 947     g_autofree uint8_t *slotkey = NULL;
 948     g_autofree uint8_t *splitkey = NULL;
 949     size_t splitkeylen = 0;
 950     size_t i;
 951     g_autoptr(QCryptoCipher) cipher = NULL;
 952     g_autoptr(QCryptoIVGen) ivgen = NULL;
 953     g_autofree char *password = NULL;
 954     const char *cipher_alg;
 955     const char *cipher_mode;
 956     const char *ivgen_alg;
 957     const char *ivgen_hash_alg = NULL;
 958     const char *hash_alg;
 959     g_autofree char *cipher_mode_spec = NULL;
 960     uint64_t iters;
 961
 962     memcpy(&luks_opts, &options->u.luks, sizeof(luks_opts));
 963     if (!luks_opts.has_iter_time) {
 964         luks_opts.iter_time = 2000;
 965     }
 966     if (!luks_opts.has_cipher_alg) {
 967         luks_opts.cipher_alg = QCRYPTO_CIPHER_ALG_AES_256;
 968     }
 969     if (!luks_opts.has_cipher_mode) {
 970         luks_opts.cipher_mode = QCRYPTO_CIPHER_MODE_XTS;
 971     }
 972     if (!luks_opts.has_ivgen_alg) {
 973         luks_opts.ivgen_alg = QCRYPTO_IVGEN_ALG_PLAIN64;
 974     }
 975     if (!luks_opts.has_hash_alg) {
 976         luks_opts.hash_alg = QCRYPTO_HASH_ALG_SHA256;
 977     }
 978     if (luks_opts.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
 979         if (!luks_opts.has_ivgen_hash_alg) {
 980             luks_opts.ivgen_hash_alg = QCRYPTO_HASH_ALG_SHA256;
 981             luks_opts.has_ivgen_hash_alg = true;
 982         }
 983     }
 984
 985     luks = g_new0(QCryptoBlockLUKS, 1);
 986     block->opaque = luks;
 987
 988     luks->cipher_alg = luks_opts.cipher_alg;
 989     luks->cipher_mode = luks_opts.cipher_mode;
 990     luks->ivgen_alg = luks_opts.ivgen_alg;
 991     luks->ivgen_hash_alg = luks_opts.ivgen_hash_alg;
 992     luks->hash_alg = luks_opts.hash_alg;
 993
 994
 995     /* Note we're allowing ivgen_hash_alg to be set even for
 996      * non-essiv iv generators that don't need a hash. It will
 997      * be silently ignored, for compatibility with dm-crypt */
 998
 999     if (!options->u.luks.key_secret) {
1000         error_setg(errp, "Parameter '%skey-secret' is required for cipher",
1001                    optprefix ? optprefix : "");
1002         goto error;
1003     }
1004     password = qcrypto_secret_lookup_as_utf8(luks_opts.key_secret, errp);
1005     if (!password) {
1006         goto error;
1007     }
1008
1009
1010     memcpy(luks->header.magic, qcrypto_block_luks_magic,
1011            QCRYPTO_BLOCK_LUKS_MAGIC_LEN);
1012
1013     /* We populate the header in native endianness initially and
1014      * then convert everything to big endian just before writing
1015      * it out to disk
1016      */
1017     luks->header.version = QCRYPTO_BLOCK_LUKS_VERSION;
1018     qcrypto_block_luks_uuid_gen(luks->header.uuid);
1019
1020     cipher_alg = qcrypto_block_luks_cipher_alg_lookup(luks_opts.cipher_alg,
1021                                                       errp);
1022     if (!cipher_alg) {
1023         goto error;
1024     }
1025
1026     cipher_mode = QCryptoCipherMode_str(luks_opts.cipher_mode);
1027     ivgen_alg = QCryptoIVGenAlgorithm_str(luks_opts.ivgen_alg);
1028     if (luks_opts.has_ivgen_hash_alg) {
1029         ivgen_hash_alg = QCryptoHashAlgorithm_str(luks_opts.ivgen_hash_alg);
1030         cipher_mode_spec = g_strdup_printf("%s-%s:%s", cipher_mode, ivgen_alg,
1031                                            ivgen_hash_alg);
1032     } else {
1033         cipher_mode_spec = g_strdup_printf("%s-%s", cipher_mode, ivgen_alg);
1034     }
1035     hash_alg = QCryptoHashAlgorithm_str(luks_opts.hash_alg);
1036
1037
1038     if (strlen(cipher_alg) >= QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN) {
1039         error_setg(errp, "Cipher name '%s' is too long for LUKS header",
1040                    cipher_alg);
1041         goto error;
1042     }
1043     if (strlen(cipher_mode_spec) >= QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN) {
1044         error_setg(errp, "Cipher mode '%s' is too long for LUKS header",
1045                    cipher_mode_spec);
1046         goto error;
1047     }
1048     if (strlen(hash_alg) >= QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN) {
1049         error_setg(errp, "Hash name '%s' is too long for LUKS header",
1050                    hash_alg);
1051         goto error;
1052     }
1053
1054     if (luks_opts.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
1055         luks->ivgen_cipher_alg =
1056                 qcrypto_block_luks_essiv_cipher(luks_opts.cipher_alg,
1057                                                 luks_opts.ivgen_hash_alg,
1058                                                 &local_err);
1059         if (local_err) {
1060             error_propagate(errp, local_err);
1061             goto error;
1062         }
1063     } else {
1064         luks->ivgen_cipher_alg = luks_opts.cipher_alg;
1065     }
1066
1067     strcpy(luks->header.cipher_name, cipher_alg);
1068     strcpy(luks->header.cipher_mode, cipher_mode_spec);
1069     strcpy(luks->header.hash_spec, hash_alg);
1070
1071     luks->header.master_key_len =
1072         qcrypto_cipher_get_key_len(luks_opts.cipher_alg);
1073
1074     if (luks_opts.cipher_mode == QCRYPTO_CIPHER_MODE_XTS) {
1075         luks->header.master_key_len *= 2;
1076     }
1077
1078     /* Generate the salt used for hashing the master key
1079      * with PBKDF later
1080      */
1081     if (qcrypto_random_bytes(luks->header.master_key_salt,
1082                              QCRYPTO_BLOCK_LUKS_SALT_LEN,
1083                              errp) < 0) {
1084         goto error;
1085     }
1086
1087     /* Generate random master key */
1088     masterkey = g_new0(uint8_t, luks->header.master_key_len);
1089     if (qcrypto_random_bytes(masterkey,
1090                              luks->header.master_key_len, errp) < 0) {
1091         goto error;
1092     }
1093
1094
1095     /* Setup the block device payload encryption objects */
1096     if (qcrypto_block_init_cipher(block, luks_opts.cipher_alg,
1097                                   luks_opts.cipher_mode, masterkey,
1098                                   luks->header.master_key_len, 1, errp) < 0) {
1099         goto error;
1100     }
1101
1102     block->kdfhash = luks_opts.hash_alg;
1103     block->niv = qcrypto_cipher_get_iv_len(luks_opts.cipher_alg,
1104                                            luks_opts.cipher_mode);
1105     block->ivgen = qcrypto_ivgen_new(luks_opts.ivgen_alg,
1106                                      luks->ivgen_cipher_alg,
1107                                      luks_opts.ivgen_hash_alg,
1108                                      masterkey, luks->header.master_key_len,
1109                                      errp);
1110
1111     if (!block->ivgen) {
1112         goto error;
1113     }
1114
1115
1116     /* Determine how many iterations we need to hash the master
1117      * key, in order to have 1 second of compute time used
1118      */
1119     iters = qcrypto_pbkdf2_count_iters(luks_opts.hash_alg,
1120                                        masterkey, luks->header.master_key_len,
1121                                        luks->header.master_key_salt,
1122                                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1123                                        QCRYPTO_BLOCK_LUKS_DIGEST_LEN,
1124                                        &local_err);
1125     if (local_err) {
1126         error_propagate(errp, local_err);
1127         goto error;
1128     }
1129
1130     if (iters > (ULLONG_MAX / luks_opts.iter_time)) {
1131         error_setg_errno(errp, ERANGE,
1132                          "PBKDF iterations %llu too large to scale",
1133                          (unsigned long long)iters);
1134         goto error;
1135     }
1136
1137     /* iter_time was in millis, but count_iters reported for secs */
1138     iters = iters * luks_opts.iter_time / 1000;
1139
1140     /* Why /= 8 ?  That matches cryptsetup, but there's no
1141      * explanation why they chose /= 8... Probably so that
1142      * if all 8 keyslots are active we only spend 1 second
1143      * in total time to check all keys */
1144     iters /= 8;
1145     if (iters > UINT32_MAX) {
1146         error_setg_errno(errp, ERANGE,
1147                          "PBKDF iterations %llu larger than %u",
1148                          (unsigned long long)iters, UINT32_MAX);
1149         goto error;
1150     }
1151     iters = MAX(iters, QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS);
1152     luks->header.master_key_iterations = iters;
1153
1154     /* Hash the master key, saving the result in the LUKS
1155      * header. This hash is used when opening the encrypted
1156      * device to verify that the user password unlocked a
1157      * valid master key
1158      */
1159     if (qcrypto_pbkdf2(luks_opts.hash_alg,
1160                        masterkey, luks->header.master_key_len,
1161                        luks->header.master_key_salt,
1162                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1163                        luks->header.master_key_iterations,
1164                        luks->header.master_key_digest,
1165                        QCRYPTO_BLOCK_LUKS_DIGEST_LEN,
1166                        errp) < 0) {
1167         goto error;
1168     }
1169
1170
1171     /* Although LUKS has multiple key slots, we're just going
1172      * to use the first key slot */
1173     splitkeylen = luks->header.master_key_len * QCRYPTO_BLOCK_LUKS_STRIPES;
1174     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1175         luks->header.key_slots[i].active = i == 0 ?
1176             QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED :
1177             QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED;
1178         luks->header.key_slots[i].stripes = QCRYPTO_BLOCK_LUKS_STRIPES;
1179
1180         /* This calculation doesn't match that shown in the spec,
1181          * but instead follows the cryptsetup implementation.
1182          */
1183         luks->header.key_slots[i].key_offset_sector =
1184             (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1185              QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) +
1186             (ROUND_UP(DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE),
1187                       (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1188                        QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) * i);
1189     }
1190
1191     if (qcrypto_random_bytes(luks->header.key_slots[0].salt,
1192                              QCRYPTO_BLOCK_LUKS_SALT_LEN,
1193                              errp) < 0) {
1194         goto error;
1195     }
1196
1197     /* Again we determine how many iterations are required to
1198      * hash the user password while consuming 1 second of compute
1199      * time */
1200     iters = qcrypto_pbkdf2_count_iters(luks_opts.hash_alg,
1201                                        (uint8_t *)password, strlen(password),
1202                                        luks->header.key_slots[0].salt,
1203                                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1204                                        luks->header.master_key_len,
1205                                        &local_err);
1206     if (local_err) {
1207         error_propagate(errp, local_err);
1208         goto error;
1209     }
1210
1211     if (iters > (ULLONG_MAX / luks_opts.iter_time)) {
1212         error_setg_errno(errp, ERANGE,
1213                          "PBKDF iterations %llu too large to scale",
1214                          (unsigned long long)iters);
1215         goto error;
1216     }
1217
1218     /* iter_time was in millis, but count_iters reported for secs */
1219     iters = iters * luks_opts.iter_time / 1000;
1220
1221     if (iters > UINT32_MAX) {
1222         error_setg_errno(errp, ERANGE,
1223                          "PBKDF iterations %llu larger than %u",
1224                          (unsigned long long)iters, UINT32_MAX);
1225         goto error;
1226     }
1227
1228     luks->header.key_slots[0].iterations =
1229         MAX(iters, QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS);
1230
1231
1232     /* Generate a key that we'll use to encrypt the master
1233      * key, from the user's password
1234      */
1235     slotkey = g_new0(uint8_t, luks->header.master_key_len);
1236     if (qcrypto_pbkdf2(luks_opts.hash_alg,
1237                        (uint8_t *)password, strlen(password),
1238                        luks->header.key_slots[0].salt,
1239                        QCRYPTO_BLOCK_LUKS_SALT_LEN,
1240                        luks->header.key_slots[0].iterations,
1241                        slotkey, luks->header.master_key_len,
1242                        errp) < 0) {
1243         goto error;
1244     }
1245
1246
1247     /* Setup the encryption objects needed to encrypt the
1248      * master key material
1249      */
1250     cipher = qcrypto_cipher_new(luks_opts.cipher_alg,
1251                                 luks_opts.cipher_mode,
1252                                 slotkey, luks->header.master_key_len,
1253                                 errp);
1254     if (!cipher) {
1255         goto error;
1256     }
1257
1258     ivgen = qcrypto_ivgen_new(luks_opts.ivgen_alg,
1259                               luks->ivgen_cipher_alg,
1260                               luks_opts.ivgen_hash_alg,
1261                               slotkey, luks->header.master_key_len,
1262                               errp);
1263     if (!ivgen) {
1264         goto error;
1265     }
1266
1267     /* Before storing the master key, we need to vastly
1268      * increase its size, as protection against forensic
1269      * disk data recovery */
1270     splitkey = g_new0(uint8_t, splitkeylen);
1271
1272     if (qcrypto_afsplit_encode(luks_opts.hash_alg,
1273                                luks->header.master_key_len,
1274                                luks->header.key_slots[0].stripes,
1275                                masterkey,
1276                                splitkey,
1277                                errp) < 0) {
1278         goto error;
1279     }
1280
1281     /* Now we encrypt the split master key with the key generated
1282      * from the user's password, before storing it */
1283     if (qcrypto_block_cipher_encrypt_helper(cipher, block->niv, ivgen,
1284                                             QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1285                                             0,
1286                                             splitkey,
1287                                             splitkeylen,
1288                                             errp) < 0) {
1289         goto error;
1290     }
1291
1292
1293     /* The total size of the LUKS headers is the partition header + key
1294      * slot headers, rounded up to the nearest sector, combined with
1295      * the size of each master key material region, also rounded up
1296      * to the nearest sector */
1297     luks->header.payload_offset_sector =
1298         (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1299          QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) +
1300         (ROUND_UP(DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE),
1301                   (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET /
1302                    QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) *
1303          QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS);
1304
1305     block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
1306     block->payload_offset = luks->header.payload_offset_sector *
1307         block->sector_size;
1308
1309     /* Reserve header space to match payload offset */
1310     initfunc(block, block->payload_offset, opaque, &local_err);
1311     if (local_err) {
1312         error_propagate(errp, local_err);
1313         goto error;
1314     }
1315
1316     if (qcrypto_block_luks_store_header(block,  writefunc, opaque, errp) < 0) {
1317         goto error;
1318     }
1319
1320     /* Write out the master key material, starting at the
1321      * sector immediately following the partition header. */
1322     if (writefunc(block,
1323                   luks->header.key_slots[0].key_offset_sector *
1324                   QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1325                   splitkey, splitkeylen,
1326                   opaque,
1327                   errp) != splitkeylen) {
1328         goto error;
1329     }
1330
1331     memset(masterkey, 0, luks->header.master_key_len);
1332     memset(slotkey, 0, luks->header.master_key_len);
1333
1334     return 0;
1335
1336  error:
1337     if (masterkey) {
1338         memset(masterkey, 0, luks->header.master_key_len);
1339     }
1340     if (slotkey) {
1341         memset(slotkey, 0, luks->header.master_key_len);
1342     }
1343
1344     qcrypto_block_free_cipher(block);
1345     qcrypto_ivgen_free(block->ivgen);
1346
1347     g_free(luks);
1348     return -1;
1349 }
1350
1351
1352 static int qcrypto_block_luks_get_info(QCryptoBlock *block,
1353                                        QCryptoBlockInfo *info,
1354                                        Error **errp)
1355 {
1356     QCryptoBlockLUKS *luks = block->opaque;
1357     QCryptoBlockInfoLUKSSlot *slot;
1358     QCryptoBlockInfoLUKSSlotList *slots = NULL, **prev = &info->u.luks.slots;
1359     size_t i;
1360
1361     info->u.luks.cipher_alg = luks->cipher_alg;
1362     info->u.luks.cipher_mode = luks->cipher_mode;
1363     info->u.luks.ivgen_alg = luks->ivgen_alg;
1364     if (info->u.luks.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
1365         info->u.luks.has_ivgen_hash_alg = true;
1366         info->u.luks.ivgen_hash_alg = luks->ivgen_hash_alg;
1367     }
1368     info->u.luks.hash_alg = luks->hash_alg;
1369     info->u.luks.payload_offset = block->payload_offset;
1370     info->u.luks.master_key_iters = luks->header.master_key_iterations;
1371     info->u.luks.uuid = g_strndup((const char *)luks->header.uuid,
1372                                   sizeof(luks->header.uuid));
1373
1374     for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
1375         slots = g_new0(QCryptoBlockInfoLUKSSlotList, 1);
1376         *prev = slots;
1377
1378         slots->value = slot = g_new0(QCryptoBlockInfoLUKSSlot, 1);
1379         slot->active = luks->header.key_slots[i].active ==
1380             QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED;
1381         slot->key_offset = luks->header.key_slots[i].key_offset_sector
1382              * QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
1383         if (slot->active) {
1384             slot->has_iters = true;
1385             slot->iters = luks->header.key_slots[i].iterations;
1386             slot->has_stripes = true;
1387             slot->stripes = luks->header.key_slots[i].stripes;
1388         }
1389
1390         prev = &slots->next;
1391     }
1392
1393     return 0;
1394 }
1395
1396
1397 static void qcrypto_block_luks_cleanup(QCryptoBlock *block)
1398 {
1399     g_free(block->opaque);
1400 }
1401
1402
1403 static int
1404 qcrypto_block_luks_decrypt(QCryptoBlock *block,
1405                            uint64_t offset,
1406                            uint8_t *buf,
1407                            size_t len,
1408                            Error **errp)
1409 {
1410     assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE));
1411     assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE));
1412     return qcrypto_block_decrypt_helper(block,
1413                                         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1414                                         offset, buf, len, errp);
1415 }
1416
1417
1418 static int
1419 qcrypto_block_luks_encrypt(QCryptoBlock *block,
1420                            uint64_t offset,
1421                            uint8_t *buf,
1422                            size_t len,
1423                            Error **errp)
1424 {
1425     assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE));
1426     assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE));
1427     return qcrypto_block_encrypt_helper(block,
1428                                         QCRYPTO_BLOCK_LUKS_SECTOR_SIZE,
1429                                         offset, buf, len, errp);
1430 }
1431
1432
1433 const QCryptoBlockDriver qcrypto_block_driver_luks = {
1434     .open = qcrypto_block_luks_open,
1435     .create = qcrypto_block_luks_create,
1436     .get_info = qcrypto_block_luks_get_info,
1437     .cleanup = qcrypto_block_luks_cleanup,
1438     .decrypt = qcrypto_block_luks_decrypt,
1439     .encrypt = qcrypto_block_luks_encrypt,
1440     .has_format = qcrypto_block_luks_has_format,
1441 };