| /* |
| * QEMU Crypto block device encryption LUKS format |
| * |
| * Copyright (c) 2015-2016 Red Hat, Inc. |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library; if not, see <http://www.gnu.org/licenses/>. |
| * |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "qapi/error.h" |
| #include "qemu/bswap.h" |
| |
| #include "block-luks.h" |
| |
| #include "crypto/hash.h" |
| #include "crypto/afsplit.h" |
| #include "crypto/pbkdf.h" |
| #include "crypto/secret.h" |
| #include "crypto/random.h" |
| #include "qemu/uuid.h" |
| |
| #include "qemu/coroutine.h" |
| |
| /* |
| * Reference for the LUKS format implemented here is |
| * |
| * docs/on-disk-format.pdf |
| * |
| * in 'cryptsetup' package source code |
| * |
| * This file implements the 1.2.1 specification, dated |
| * Oct 16, 2011. |
| */ |
| |
| typedef struct QCryptoBlockLUKS QCryptoBlockLUKS; |
| typedef struct QCryptoBlockLUKSHeader QCryptoBlockLUKSHeader; |
| typedef struct QCryptoBlockLUKSKeySlot QCryptoBlockLUKSKeySlot; |
| |
| |
| /* The following constants are all defined by the LUKS spec */ |
| #define QCRYPTO_BLOCK_LUKS_VERSION 1 |
| |
| #define QCRYPTO_BLOCK_LUKS_MAGIC_LEN 6 |
| #define QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN 32 |
| #define QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN 32 |
| #define QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN 32 |
| #define QCRYPTO_BLOCK_LUKS_DIGEST_LEN 20 |
| #define QCRYPTO_BLOCK_LUKS_SALT_LEN 32 |
| #define QCRYPTO_BLOCK_LUKS_UUID_LEN 40 |
| #define QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS 8 |
| #define QCRYPTO_BLOCK_LUKS_STRIPES 4000 |
| #define QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS 1000 |
| #define QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS 1000 |
| #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET 4096 |
| |
| #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED 0x0000DEAD |
| #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED 0x00AC71F3 |
| |
| #define QCRYPTO_BLOCK_LUKS_SECTOR_SIZE 512LL |
| |
| static const char qcrypto_block_luks_magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN] = { |
| 'L', 'U', 'K', 'S', 0xBA, 0xBE |
| }; |
| |
| typedef struct QCryptoBlockLUKSNameMap QCryptoBlockLUKSNameMap; |
| struct QCryptoBlockLUKSNameMap { |
| const char *name; |
| int id; |
| }; |
| |
| typedef struct QCryptoBlockLUKSCipherSizeMap QCryptoBlockLUKSCipherSizeMap; |
| struct QCryptoBlockLUKSCipherSizeMap { |
| uint32_t key_bytes; |
| int id; |
| }; |
| typedef struct QCryptoBlockLUKSCipherNameMap QCryptoBlockLUKSCipherNameMap; |
| struct QCryptoBlockLUKSCipherNameMap { |
| const char *name; |
| const QCryptoBlockLUKSCipherSizeMap *sizes; |
| }; |
| |
| |
| static const QCryptoBlockLUKSCipherSizeMap |
| qcrypto_block_luks_cipher_size_map_aes[] = { |
| { 16, QCRYPTO_CIPHER_ALG_AES_128 }, |
| { 24, QCRYPTO_CIPHER_ALG_AES_192 }, |
| { 32, QCRYPTO_CIPHER_ALG_AES_256 }, |
| { 0, 0 }, |
| }; |
| |
| static const QCryptoBlockLUKSCipherSizeMap |
| qcrypto_block_luks_cipher_size_map_cast5[] = { |
| { 16, QCRYPTO_CIPHER_ALG_CAST5_128 }, |
| { 0, 0 }, |
| }; |
| |
| static const QCryptoBlockLUKSCipherSizeMap |
| qcrypto_block_luks_cipher_size_map_serpent[] = { |
| { 16, QCRYPTO_CIPHER_ALG_SERPENT_128 }, |
| { 24, QCRYPTO_CIPHER_ALG_SERPENT_192 }, |
| { 32, QCRYPTO_CIPHER_ALG_SERPENT_256 }, |
| { 0, 0 }, |
| }; |
| |
| static const QCryptoBlockLUKSCipherSizeMap |
| qcrypto_block_luks_cipher_size_map_twofish[] = { |
| { 16, QCRYPTO_CIPHER_ALG_TWOFISH_128 }, |
| { 24, QCRYPTO_CIPHER_ALG_TWOFISH_192 }, |
| { 32, QCRYPTO_CIPHER_ALG_TWOFISH_256 }, |
| { 0, 0 }, |
| }; |
| |
| static const QCryptoBlockLUKSCipherNameMap |
| qcrypto_block_luks_cipher_name_map[] = { |
| { "aes", qcrypto_block_luks_cipher_size_map_aes }, |
| { "cast5", qcrypto_block_luks_cipher_size_map_cast5 }, |
| { "serpent", qcrypto_block_luks_cipher_size_map_serpent }, |
| { "twofish", qcrypto_block_luks_cipher_size_map_twofish }, |
| }; |
| |
| |
| /* |
| * This struct is written to disk in big-endian format, |
| * but operated upon in native-endian format. |
| */ |
| struct QCryptoBlockLUKSKeySlot { |
| /* state of keyslot, enabled/disable */ |
| uint32_t active; |
| /* iterations for PBKDF2 */ |
| uint32_t iterations; |
| /* salt for PBKDF2 */ |
| uint8_t salt[QCRYPTO_BLOCK_LUKS_SALT_LEN]; |
| /* start sector of key material */ |
| uint32_t key_offset_sector; |
| /* number of anti-forensic stripes */ |
| uint32_t stripes; |
| }; |
| |
| QEMU_BUILD_BUG_ON(sizeof(struct QCryptoBlockLUKSKeySlot) != 48); |
| |
| |
| /* |
| * This struct is written to disk in big-endian format, |
| * but operated upon in native-endian format. |
| */ |
| struct QCryptoBlockLUKSHeader { |
| /* 'L', 'U', 'K', 'S', '0xBA', '0xBE' */ |
| char magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN]; |
| |
| /* LUKS version, currently 1 */ |
| uint16_t version; |
| |
| /* cipher name specification (aes, etc) */ |
| char cipher_name[QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN]; |
| |
| /* cipher mode specification (cbc-plain, xts-essiv:sha256, etc) */ |
| char cipher_mode[QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN]; |
| |
| /* hash specification (sha256, etc) */ |
| char hash_spec[QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN]; |
| |
| /* start offset of the volume data (in 512 byte sectors) */ |
| uint32_t payload_offset_sector; |
| |
| /* Number of key bytes */ |
| uint32_t master_key_len; |
| |
| /* master key checksum after PBKDF2 */ |
| uint8_t master_key_digest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN]; |
| |
| /* salt for master key PBKDF2 */ |
| uint8_t master_key_salt[QCRYPTO_BLOCK_LUKS_SALT_LEN]; |
| |
| /* iterations for master key PBKDF2 */ |
| uint32_t master_key_iterations; |
| |
| /* UUID of the partition in standard ASCII representation */ |
| uint8_t uuid[QCRYPTO_BLOCK_LUKS_UUID_LEN]; |
| |
| /* key slots */ |
| QCryptoBlockLUKSKeySlot key_slots[QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS]; |
| }; |
| |
| QEMU_BUILD_BUG_ON(sizeof(struct QCryptoBlockLUKSHeader) != 592); |
| |
| |
| struct QCryptoBlockLUKS { |
| QCryptoBlockLUKSHeader header; |
| |
| /* Main encryption algorithm used for encryption*/ |
| QCryptoCipherAlgorithm cipher_alg; |
| |
| /* Mode of encryption for the selected encryption algorithm */ |
| QCryptoCipherMode cipher_mode; |
| |
| /* Initialization vector generation algorithm */ |
| QCryptoIVGenAlgorithm ivgen_alg; |
| |
| /* Hash algorithm used for IV generation*/ |
| QCryptoHashAlgorithm ivgen_hash_alg; |
| |
| /* |
| * Encryption algorithm used for IV generation. |
| * Usually the same as main encryption algorithm |
| */ |
| QCryptoCipherAlgorithm ivgen_cipher_alg; |
| |
| /* Hash algorithm used in pbkdf2 function */ |
| QCryptoHashAlgorithm hash_alg; |
| }; |
| |
| |
| static int qcrypto_block_luks_cipher_name_lookup(const char *name, |
| QCryptoCipherMode mode, |
| uint32_t key_bytes, |
| Error **errp) |
| { |
| const QCryptoBlockLUKSCipherNameMap *map = |
| qcrypto_block_luks_cipher_name_map; |
| size_t maplen = G_N_ELEMENTS(qcrypto_block_luks_cipher_name_map); |
| size_t i, j; |
| |
| if (mode == QCRYPTO_CIPHER_MODE_XTS) { |
| key_bytes /= 2; |
| } |
| |
| for (i = 0; i < maplen; i++) { |
| if (!g_str_equal(map[i].name, name)) { |
| continue; |
| } |
| for (j = 0; j < map[i].sizes[j].key_bytes; j++) { |
| if (map[i].sizes[j].key_bytes == key_bytes) { |
| return map[i].sizes[j].id; |
| } |
| } |
| } |
| |
| error_setg(errp, "Algorithm %s with key size %d bytes not supported", |
| name, key_bytes); |
| return 0; |
| } |
| |
| static const char * |
| qcrypto_block_luks_cipher_alg_lookup(QCryptoCipherAlgorithm alg, |
| Error **errp) |
| { |
| const QCryptoBlockLUKSCipherNameMap *map = |
| qcrypto_block_luks_cipher_name_map; |
| size_t maplen = G_N_ELEMENTS(qcrypto_block_luks_cipher_name_map); |
| size_t i, j; |
| for (i = 0; i < maplen; i++) { |
| for (j = 0; j < map[i].sizes[j].key_bytes; j++) { |
| if (map[i].sizes[j].id == alg) { |
| return map[i].name; |
| } |
| } |
| } |
| |
| error_setg(errp, "Algorithm '%s' not supported", |
| QCryptoCipherAlgorithm_str(alg)); |
| return NULL; |
| } |
| |
| /* XXX replace with qapi_enum_parse() in future, when we can |
| * make that function emit a more friendly error message */ |
| static int qcrypto_block_luks_name_lookup(const char *name, |
| const QEnumLookup *map, |
| const char *type, |
| Error **errp) |
| { |
| int ret = qapi_enum_parse(map, name, -1, NULL); |
| |
| if (ret < 0) { |
| error_setg(errp, "%s %s not supported", type, name); |
| return 0; |
| } |
| return ret; |
| } |
| |
| #define qcrypto_block_luks_cipher_mode_lookup(name, errp) \ |
| qcrypto_block_luks_name_lookup(name, \ |
| &QCryptoCipherMode_lookup, \ |
| "Cipher mode", \ |
| errp) |
| |
| #define qcrypto_block_luks_hash_name_lookup(name, errp) \ |
| qcrypto_block_luks_name_lookup(name, \ |
| &QCryptoHashAlgorithm_lookup, \ |
| "Hash algorithm", \ |
| errp) |
| |
| #define qcrypto_block_luks_ivgen_name_lookup(name, errp) \ |
| qcrypto_block_luks_name_lookup(name, \ |
| &QCryptoIVGenAlgorithm_lookup, \ |
| "IV generator", \ |
| errp) |
| |
| |
| static bool |
| qcrypto_block_luks_has_format(const uint8_t *buf, |
| size_t buf_size) |
| { |
| const QCryptoBlockLUKSHeader *luks_header = (const void *)buf; |
| |
| if (buf_size >= offsetof(QCryptoBlockLUKSHeader, cipher_name) && |
| memcmp(luks_header->magic, qcrypto_block_luks_magic, |
| QCRYPTO_BLOCK_LUKS_MAGIC_LEN) == 0 && |
| be16_to_cpu(luks_header->version) == QCRYPTO_BLOCK_LUKS_VERSION) { |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| |
| /** |
| * Deal with a quirk of dm-crypt usage of ESSIV. |
| * |
| * When calculating ESSIV IVs, the cipher length used by ESSIV |
| * may be different from the cipher length used for the block |
| * encryption, becauses dm-crypt uses the hash digest length |
| * as the key size. ie, if you have AES 128 as the block cipher |
| * and SHA 256 as ESSIV hash, then ESSIV will use AES 256 as |
| * the cipher since that gets a key length matching the digest |
| * size, not AES 128 with truncated digest as might be imagined |
| */ |
| static QCryptoCipherAlgorithm |
| qcrypto_block_luks_essiv_cipher(QCryptoCipherAlgorithm cipher, |
| QCryptoHashAlgorithm hash, |
| Error **errp) |
| { |
| size_t digestlen = qcrypto_hash_digest_len(hash); |
| size_t keylen = qcrypto_cipher_get_key_len(cipher); |
| if (digestlen == keylen) { |
| return cipher; |
| } |
| |
| switch (cipher) { |
| case QCRYPTO_CIPHER_ALG_AES_128: |
| case QCRYPTO_CIPHER_ALG_AES_192: |
| case QCRYPTO_CIPHER_ALG_AES_256: |
| if (digestlen == qcrypto_cipher_get_key_len( |
| QCRYPTO_CIPHER_ALG_AES_128)) { |
| return QCRYPTO_CIPHER_ALG_AES_128; |
| } else if (digestlen == qcrypto_cipher_get_key_len( |
| QCRYPTO_CIPHER_ALG_AES_192)) { |
| return QCRYPTO_CIPHER_ALG_AES_192; |
| } else if (digestlen == qcrypto_cipher_get_key_len( |
| QCRYPTO_CIPHER_ALG_AES_256)) { |
| return QCRYPTO_CIPHER_ALG_AES_256; |
| } else { |
| error_setg(errp, "No AES cipher with key size %zu available", |
| digestlen); |
| return 0; |
| } |
| break; |
| case QCRYPTO_CIPHER_ALG_SERPENT_128: |
| case QCRYPTO_CIPHER_ALG_SERPENT_192: |
| case QCRYPTO_CIPHER_ALG_SERPENT_256: |
| if (digestlen == qcrypto_cipher_get_key_len( |
| QCRYPTO_CIPHER_ALG_SERPENT_128)) { |
| return QCRYPTO_CIPHER_ALG_SERPENT_128; |
| } else if (digestlen == qcrypto_cipher_get_key_len( |
| QCRYPTO_CIPHER_ALG_SERPENT_192)) { |
| return QCRYPTO_CIPHER_ALG_SERPENT_192; |
| } else if (digestlen == qcrypto_cipher_get_key_len( |
| QCRYPTO_CIPHER_ALG_SERPENT_256)) { |
| return QCRYPTO_CIPHER_ALG_SERPENT_256; |
| } else { |
| error_setg(errp, "No Serpent cipher with key size %zu available", |
| digestlen); |
| return 0; |
| } |
| break; |
| case QCRYPTO_CIPHER_ALG_TWOFISH_128: |
| case QCRYPTO_CIPHER_ALG_TWOFISH_192: |
| case QCRYPTO_CIPHER_ALG_TWOFISH_256: |
| if (digestlen == qcrypto_cipher_get_key_len( |
| QCRYPTO_CIPHER_ALG_TWOFISH_128)) { |
| return QCRYPTO_CIPHER_ALG_TWOFISH_128; |
| } else if (digestlen == qcrypto_cipher_get_key_len( |
| QCRYPTO_CIPHER_ALG_TWOFISH_192)) { |
| return QCRYPTO_CIPHER_ALG_TWOFISH_192; |
| } else if (digestlen == qcrypto_cipher_get_key_len( |
| QCRYPTO_CIPHER_ALG_TWOFISH_256)) { |
| return QCRYPTO_CIPHER_ALG_TWOFISH_256; |
| } else { |
| error_setg(errp, "No Twofish cipher with key size %zu available", |
| digestlen); |
| return 0; |
| } |
| break; |
| default: |
| error_setg(errp, "Cipher %s not supported with essiv", |
| QCryptoCipherAlgorithm_str(cipher)); |
| return 0; |
| } |
| } |
| |
| /* |
| * Returns number of sectors needed to store the key material |
| * given number of anti forensic stripes |
| */ |
| static int |
| qcrypto_block_luks_splitkeylen_sectors(const QCryptoBlockLUKS *luks, |
| unsigned int header_sectors, |
| unsigned int stripes) |
| { |
| /* |
| * This calculation doesn't match that shown in the spec, |
| * but instead follows the cryptsetup implementation. |
| */ |
| |
| size_t splitkeylen = luks->header.master_key_len * stripes; |
| |
| /* First align the key material size to block size*/ |
| size_t splitkeylen_sectors = |
| DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE); |
| |
| /* Then also align the key material size to the size of the header */ |
| return ROUND_UP(splitkeylen_sectors, header_sectors); |
| } |
| |
| /* |
| * Stores the main LUKS header, taking care of endianess |
| */ |
| static int |
| qcrypto_block_luks_store_header(QCryptoBlock *block, |
| QCryptoBlockWriteFunc writefunc, |
| void *opaque, |
| Error **errp) |
| { |
| const QCryptoBlockLUKS *luks = block->opaque; |
| Error *local_err = NULL; |
| size_t i; |
| g_autofree QCryptoBlockLUKSHeader *hdr_copy = NULL; |
| |
| /* Create a copy of the header */ |
| hdr_copy = g_new0(QCryptoBlockLUKSHeader, 1); |
| memcpy(hdr_copy, &luks->header, sizeof(QCryptoBlockLUKSHeader)); |
| |
| /* |
| * Everything on disk uses Big Endian (tm), so flip header fields |
| * before writing them |
| */ |
| cpu_to_be16s(&hdr_copy->version); |
| cpu_to_be32s(&hdr_copy->payload_offset_sector); |
| cpu_to_be32s(&hdr_copy->master_key_len); |
| cpu_to_be32s(&hdr_copy->master_key_iterations); |
| |
| for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { |
| cpu_to_be32s(&hdr_copy->key_slots[i].active); |
| cpu_to_be32s(&hdr_copy->key_slots[i].iterations); |
| cpu_to_be32s(&hdr_copy->key_slots[i].key_offset_sector); |
| cpu_to_be32s(&hdr_copy->key_slots[i].stripes); |
| } |
| |
| /* Write out the partition header and key slot headers */ |
| writefunc(block, 0, (const uint8_t *)hdr_copy, sizeof(*hdr_copy), |
| opaque, &local_err); |
| |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return -1; |
| } |
| return 0; |
| } |
| |
| /* |
| * Loads the main LUKS header,and byteswaps it to native endianess |
| * And run basic sanity checks on it |
| */ |
| static int |
| qcrypto_block_luks_load_header(QCryptoBlock *block, |
| QCryptoBlockReadFunc readfunc, |
| void *opaque, |
| Error **errp) |
| { |
| ssize_t rv; |
| size_t i; |
| QCryptoBlockLUKS *luks = block->opaque; |
| |
| /* |
| * Read the entire LUKS header, minus the key material from |
| * the underlying device |
| */ |
| rv = readfunc(block, 0, |
| (uint8_t *)&luks->header, |
| sizeof(luks->header), |
| opaque, |
| errp); |
| if (rv < 0) { |
| return rv; |
| } |
| |
| /* |
| * The header is always stored in big-endian format, so |
| * convert everything to native |
| */ |
| be16_to_cpus(&luks->header.version); |
| be32_to_cpus(&luks->header.payload_offset_sector); |
| be32_to_cpus(&luks->header.master_key_len); |
| be32_to_cpus(&luks->header.master_key_iterations); |
| |
| for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { |
| be32_to_cpus(&luks->header.key_slots[i].active); |
| be32_to_cpus(&luks->header.key_slots[i].iterations); |
| be32_to_cpus(&luks->header.key_slots[i].key_offset_sector); |
| be32_to_cpus(&luks->header.key_slots[i].stripes); |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Does basic sanity checks on the LUKS header |
| */ |
| static int |
| qcrypto_block_luks_check_header(const QCryptoBlockLUKS *luks, Error **errp) |
| { |
| size_t i, j; |
| |
| unsigned int header_sectors = QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET / |
| QCRYPTO_BLOCK_LUKS_SECTOR_SIZE; |
| |
| if (memcmp(luks->header.magic, qcrypto_block_luks_magic, |
| QCRYPTO_BLOCK_LUKS_MAGIC_LEN) != 0) { |
| error_setg(errp, "Volume is not in LUKS format"); |
| return -1; |
| } |
| |
| if (luks->header.version != QCRYPTO_BLOCK_LUKS_VERSION) { |
| error_setg(errp, "LUKS version %" PRIu32 " is not supported", |
| luks->header.version); |
| return -1; |
| } |
| |
| /* Check all keyslots for corruption */ |
| for (i = 0 ; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS ; i++) { |
| |
| const QCryptoBlockLUKSKeySlot *slot1 = &luks->header.key_slots[i]; |
| unsigned int start1 = slot1->key_offset_sector; |
| unsigned int len1 = |
| qcrypto_block_luks_splitkeylen_sectors(luks, |
| header_sectors, |
| slot1->stripes); |
| |
| if (slot1->stripes == 0) { |
| error_setg(errp, "Keyslot %zu is corrupted (stripes == 0)", i); |
| return -1; |
| } |
| |
| if (slot1->active != QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED && |
| slot1->active != QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED) { |
| error_setg(errp, |
| "Keyslot %zu state (active/disable) is corrupted", i); |
| return -1; |
| } |
| |
| if (start1 + len1 > luks->header.payload_offset_sector) { |
| error_setg(errp, |
| "Keyslot %zu is overlapping with the encrypted payload", |
| i); |
| return -1; |
| } |
| |
| for (j = i + 1 ; j < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS ; j++) { |
| const QCryptoBlockLUKSKeySlot *slot2 = &luks->header.key_slots[j]; |
| unsigned int start2 = slot2->key_offset_sector; |
| unsigned int len2 = |
| qcrypto_block_luks_splitkeylen_sectors(luks, |
| header_sectors, |
| slot2->stripes); |
| |
| if (start1 + len1 > start2 && start2 + len2 > start1) { |
| error_setg(errp, |
| "Keyslots %zu and %zu are overlapping in the header", |
| i, j); |
| return -1; |
| } |
| } |
| |
| } |
| return 0; |
| } |
| |
| /* |
| * Parses the crypto parameters that are stored in the LUKS header |
| */ |
| |
| static int |
| qcrypto_block_luks_parse_header(QCryptoBlockLUKS *luks, Error **errp) |
| { |
| g_autofree char *cipher_mode = g_strdup(luks->header.cipher_mode); |
| char *ivgen_name, *ivhash_name; |
| Error *local_err = NULL; |
| |
| /* |
| * The cipher_mode header contains a string that we have |
| * to further parse, of the format |
| * |
| * <cipher-mode>-<iv-generator>[:<iv-hash>] |
| * |
| * eg cbc-essiv:sha256, cbc-plain64 |
| */ |
| ivgen_name = strchr(cipher_mode, '-'); |
| if (!ivgen_name) { |
| error_setg(errp, "Unexpected cipher mode string format %s", |
| luks->header.cipher_mode); |
| return -1; |
| } |
| *ivgen_name = '\0'; |
| ivgen_name++; |
| |
| ivhash_name = strchr(ivgen_name, ':'); |
| if (!ivhash_name) { |
| luks->ivgen_hash_alg = 0; |
| } else { |
| *ivhash_name = '\0'; |
| ivhash_name++; |
| |
| luks->ivgen_hash_alg = qcrypto_block_luks_hash_name_lookup(ivhash_name, |
| &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return -1; |
| } |
| } |
| |
| luks->cipher_mode = qcrypto_block_luks_cipher_mode_lookup(cipher_mode, |
| &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return -1; |
| } |
| |
| luks->cipher_alg = |
| qcrypto_block_luks_cipher_name_lookup(luks->header.cipher_name, |
| luks->cipher_mode, |
| luks->header.master_key_len, |
| &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return -1; |
| } |
| |
| luks->hash_alg = |
| qcrypto_block_luks_hash_name_lookup(luks->header.hash_spec, |
| &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return -1; |
| } |
| |
| luks->ivgen_alg = qcrypto_block_luks_ivgen_name_lookup(ivgen_name, |
| &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return -1; |
| } |
| |
| if (luks->ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) { |
| if (!ivhash_name) { |
| error_setg(errp, "Missing IV generator hash specification"); |
| return -1; |
| } |
| luks->ivgen_cipher_alg = |
| qcrypto_block_luks_essiv_cipher(luks->cipher_alg, |
| luks->ivgen_hash_alg, |
| &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return -1; |
| } |
| } else { |
| |
| /* |
| * Note we parsed the ivhash_name earlier in the cipher_mode |
| * spec string even with plain/plain64 ivgens, but we |
| * will ignore it, since it is irrelevant for these ivgens. |
| * This is for compat with dm-crypt which will silently |
| * ignore hash names with these ivgens rather than report |
| * an error about the invalid usage |
| */ |
| luks->ivgen_cipher_alg = luks->cipher_alg; |
| } |
| return 0; |
| } |
| |
| /* |
| * Given a key slot, user password, and the master key, |
| * will store the encrypted master key there, and update the |
| * in-memory header. User must then write the in-memory header |
| * |
| * Returns: |
| * 0 if the keyslot was written successfully |
| * with the provided password |
| * -1 if a fatal error occurred while storing the key |
| */ |
| static int |
| qcrypto_block_luks_store_key(QCryptoBlock *block, |
| unsigned int slot_idx, |
| const char *password, |
| uint8_t *masterkey, |
| uint64_t iter_time, |
| QCryptoBlockWriteFunc writefunc, |
| void *opaque, |
| Error **errp) |
| { |
| QCryptoBlockLUKS *luks = block->opaque; |
| QCryptoBlockLUKSKeySlot *slot = &luks->header.key_slots[slot_idx]; |
| g_autofree uint8_t *splitkey = NULL; |
| size_t splitkeylen; |
| g_autofree uint8_t *slotkey = NULL; |
| g_autoptr(QCryptoCipher) cipher = NULL; |
| g_autoptr(QCryptoIVGen) ivgen = NULL; |
| Error *local_err = NULL; |
| uint64_t iters; |
| int ret = -1; |
| |
| if (qcrypto_random_bytes(slot->salt, |
| QCRYPTO_BLOCK_LUKS_SALT_LEN, |
| errp) < 0) { |
| goto cleanup; |
| } |
| |
| splitkeylen = luks->header.master_key_len * slot->stripes; |
| |
| /* |
| * Determine how many iterations are required to |
| * hash the user password while consuming 1 second of compute |
| * time |
| */ |
| iters = qcrypto_pbkdf2_count_iters(luks->hash_alg, |
| (uint8_t *)password, strlen(password), |
| slot->salt, |
| QCRYPTO_BLOCK_LUKS_SALT_LEN, |
| luks->header.master_key_len, |
| &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| goto cleanup; |
| } |
| |
| if (iters > (ULLONG_MAX / iter_time)) { |
| error_setg_errno(errp, ERANGE, |
| "PBKDF iterations %llu too large to scale", |
| (unsigned long long)iters); |
| goto cleanup; |
| } |
| |
| /* iter_time was in millis, but count_iters reported for secs */ |
| iters = iters * iter_time / 1000; |
| |
| if (iters > UINT32_MAX) { |
| error_setg_errno(errp, ERANGE, |
| "PBKDF iterations %llu larger than %u", |
| (unsigned long long)iters, UINT32_MAX); |
| goto cleanup; |
| } |
| |
| slot->iterations = |
| MAX(iters, QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS); |
| |
| |
| /* |
| * Generate a key that we'll use to encrypt the master |
| * key, from the user's password |
| */ |
| slotkey = g_new0(uint8_t, luks->header.master_key_len); |
| if (qcrypto_pbkdf2(luks->hash_alg, |
| (uint8_t *)password, strlen(password), |
| slot->salt, |
| QCRYPTO_BLOCK_LUKS_SALT_LEN, |
| slot->iterations, |
| slotkey, luks->header.master_key_len, |
| errp) < 0) { |
| goto cleanup; |
| } |
| |
| |
| /* |
| * Setup the encryption objects needed to encrypt the |
| * master key material |
| */ |
| cipher = qcrypto_cipher_new(luks->cipher_alg, |
| luks->cipher_mode, |
| slotkey, luks->header.master_key_len, |
| errp); |
| if (!cipher) { |
| goto cleanup; |
| } |
| |
| ivgen = qcrypto_ivgen_new(luks->ivgen_alg, |
| luks->ivgen_cipher_alg, |
| luks->ivgen_hash_alg, |
| slotkey, luks->header.master_key_len, |
| errp); |
| if (!ivgen) { |
| goto cleanup; |
| } |
| |
| /* |
| * Before storing the master key, we need to vastly |
| * increase its size, as protection against forensic |
| * disk data recovery |
| */ |
| splitkey = g_new0(uint8_t, splitkeylen); |
| |
| if (qcrypto_afsplit_encode(luks->hash_alg, |
| luks->header.master_key_len, |
| slot->stripes, |
| masterkey, |
| splitkey, |
| errp) < 0) { |
| goto cleanup; |
| } |
| |
| /* |
| * Now we encrypt the split master key with the key generated |
| * from the user's password, before storing it |
| */ |
| if (qcrypto_block_cipher_encrypt_helper(cipher, block->niv, ivgen, |
| QCRYPTO_BLOCK_LUKS_SECTOR_SIZE, |
| 0, |
| splitkey, |
| splitkeylen, |
| errp) < 0) { |
| goto cleanup; |
| } |
| |
| /* Write out the slot's master key material. */ |
| if (writefunc(block, |
| slot->key_offset_sector * |
| QCRYPTO_BLOCK_LUKS_SECTOR_SIZE, |
| splitkey, splitkeylen, |
| opaque, |
| errp) != splitkeylen) { |
| goto cleanup; |
| } |
| |
| slot->active = QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED; |
| |
| if (qcrypto_block_luks_store_header(block, writefunc, opaque, errp) < 0) { |
| goto cleanup; |
| } |
| |
| ret = 0; |
| |
| cleanup: |
| if (slotkey) { |
| memset(slotkey, 0, luks->header.master_key_len); |
| } |
| if (splitkey) { |
| memset(splitkey, 0, splitkeylen); |
| } |
| return ret; |
| } |
| |
| /* |
| * Given a key slot, and user password, this will attempt to unlock |
| * the master encryption key from the key slot. |
| * |
| * Returns: |
| * 0 if the key slot is disabled, or key could not be decrypted |
| * with the provided password |
| * 1 if the key slot is enabled, and key decrypted successfully |
| * with the provided password |
| * -1 if a fatal error occurred loading the key |
| */ |
| static int |
| qcrypto_block_luks_load_key(QCryptoBlock *block, |
| size_t slot_idx, |
| const char *password, |
| uint8_t *masterkey, |
| QCryptoBlockReadFunc readfunc, |
| void *opaque, |
| Error **errp) |
| { |
| QCryptoBlockLUKS *luks = block->opaque; |
| const QCryptoBlockLUKSKeySlot *slot = &luks->header.key_slots[slot_idx]; |
| g_autofree uint8_t *splitkey = NULL; |
| size_t splitkeylen; |
| g_autofree uint8_t *possiblekey = NULL; |
| ssize_t rv; |
| g_autoptr(QCryptoCipher) cipher = NULL; |
| uint8_t keydigest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN]; |
| g_autoptr(QCryptoIVGen) ivgen = NULL; |
| size_t niv; |
| |
| if (slot->active != QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED) { |
| return 0; |
| } |
| |
| splitkeylen = luks->header.master_key_len * slot->stripes; |
| splitkey = g_new0(uint8_t, splitkeylen); |
| possiblekey = g_new0(uint8_t, luks->header.master_key_len); |
| |
| /* |
| * The user password is used to generate a (possible) |
| * decryption key. This may or may not successfully |
| * decrypt the master key - we just blindly assume |
| * the key is correct and validate the results of |
| * decryption later. |
| */ |
| if (qcrypto_pbkdf2(luks->hash_alg, |
| (const uint8_t *)password, strlen(password), |
| slot->salt, QCRYPTO_BLOCK_LUKS_SALT_LEN, |
| slot->iterations, |
| possiblekey, luks->header.master_key_len, |
| errp) < 0) { |
| return -1; |
| } |
| |
| /* |
| * We need to read the master key material from the |
| * LUKS key material header. What we're reading is |
| * not the raw master key, but rather the data after |
| * it has been passed through AFSplit and the result |
| * then encrypted. |
| */ |
| rv = readfunc(block, |
| slot->key_offset_sector * QCRYPTO_BLOCK_LUKS_SECTOR_SIZE, |
| splitkey, splitkeylen, |
| opaque, |
| errp); |
| if (rv < 0) { |
| return -1; |
| } |
| |
| |
| /* Setup the cipher/ivgen that we'll use to try to decrypt |
| * the split master key material */ |
| cipher = qcrypto_cipher_new(luks->cipher_alg, |
| luks->cipher_mode, |
| possiblekey, |
| luks->header.master_key_len, |
| errp); |
| if (!cipher) { |
| return -1; |
| } |
| |
| niv = qcrypto_cipher_get_iv_len(luks->cipher_alg, |
| luks->cipher_mode); |
| |
| ivgen = qcrypto_ivgen_new(luks->ivgen_alg, |
| luks->ivgen_cipher_alg, |
| luks->ivgen_hash_alg, |
| possiblekey, |
| luks->header.master_key_len, |
| errp); |
| if (!ivgen) { |
| return -1; |
| } |
| |
| |
| /* |
| * The master key needs to be decrypted in the same |
| * way that the block device payload will be decrypted |
| * later. In particular we'll be using the IV generator |
| * to reset the encryption cipher every time the master |
| * key crosses a sector boundary. |
| */ |
| if (qcrypto_block_cipher_decrypt_helper(cipher, |
| niv, |
| ivgen, |
| QCRYPTO_BLOCK_LUKS_SECTOR_SIZE, |
| 0, |
| splitkey, |
| splitkeylen, |
| errp) < 0) { |
| return -1; |
| } |
| |
| /* |
| * Now we've decrypted the split master key, join |
| * it back together to get the actual master key. |
| */ |
| if (qcrypto_afsplit_decode(luks->hash_alg, |
| luks->header.master_key_len, |
| slot->stripes, |
| splitkey, |
| masterkey, |
| errp) < 0) { |
| return -1; |
| } |
| |
| |
| /* |
| * We still don't know that the masterkey we got is valid, |
| * because we just blindly assumed the user's password |
| * was correct. This is where we now verify it. We are |
| * creating a hash of the master key using PBKDF and |
| * then comparing that to the hash stored in the key slot |
| * header |
| */ |
| if (qcrypto_pbkdf2(luks->hash_alg, |
| masterkey, |
| luks->header.master_key_len, |
| luks->header.master_key_salt, |
| QCRYPTO_BLOCK_LUKS_SALT_LEN, |
| luks->header.master_key_iterations, |
| keydigest, |
| G_N_ELEMENTS(keydigest), |
| errp) < 0) { |
| return -1; |
| } |
| |
| if (memcmp(keydigest, luks->header.master_key_digest, |
| QCRYPTO_BLOCK_LUKS_DIGEST_LEN) == 0) { |
| /* Success, we got the right master key */ |
| return 1; |
| } |
| |
| /* Fail, user's password was not valid for this key slot, |
| * tell caller to try another slot */ |
| return 0; |
| } |
| |
| |
| /* |
| * Given a user password, this will iterate over all key |
| * slots and try to unlock each active key slot using the |
| * password until it successfully obtains a master key. |
| * |
| * Returns 0 if a key was loaded, -1 if no keys could be loaded |
| */ |
| static int |
| qcrypto_block_luks_find_key(QCryptoBlock *block, |
| const char *password, |
| uint8_t *masterkey, |
| QCryptoBlockReadFunc readfunc, |
| void *opaque, |
| Error **errp) |
| { |
| size_t i; |
| int rv; |
| |
| for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { |
| rv = qcrypto_block_luks_load_key(block, |
| i, |
| password, |
| masterkey, |
| readfunc, |
| opaque, |
| errp); |
| if (rv < 0) { |
| goto error; |
| } |
| if (rv == 1) { |
| return 0; |
| } |
| } |
| |
| error_setg(errp, "Invalid password, cannot unlock any keyslot"); |
| error: |
| return -1; |
| } |
| |
| |
| static int |
| qcrypto_block_luks_open(QCryptoBlock *block, |
| QCryptoBlockOpenOptions *options, |
| const char *optprefix, |
| QCryptoBlockReadFunc readfunc, |
| void *opaque, |
| unsigned int flags, |
| size_t n_threads, |
| Error **errp) |
| { |
| QCryptoBlockLUKS *luks = NULL; |
| g_autofree uint8_t *masterkey = NULL; |
| g_autofree char *password = NULL; |
| |
| if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) { |
| if (!options->u.luks.key_secret) { |
| error_setg(errp, "Parameter '%skey-secret' is required for cipher", |
| optprefix ? optprefix : ""); |
| return -1; |
| } |
| password = qcrypto_secret_lookup_as_utf8( |
| options->u.luks.key_secret, errp); |
| if (!password) { |
| return -1; |
| } |
| } |
| |
| luks = g_new0(QCryptoBlockLUKS, 1); |
| block->opaque = luks; |
| |
| if (qcrypto_block_luks_load_header(block, readfunc, opaque, errp) < 0) { |
| goto fail; |
| } |
| |
| if (qcrypto_block_luks_check_header(luks, errp) < 0) { |
| goto fail; |
| } |
| |
| if (qcrypto_block_luks_parse_header(luks, errp) < 0) { |
| goto fail; |
| } |
| |
| if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) { |
| /* Try to find which key slot our password is valid for |
| * and unlock the master key from that slot. |
| */ |
| |
| masterkey = g_new0(uint8_t, luks->header.master_key_len); |
| |
| if (qcrypto_block_luks_find_key(block, |
| password, |
| masterkey, |
| readfunc, opaque, |
| errp) < 0) { |
| goto fail; |
| } |
| |
| /* We have a valid master key now, so can setup the |
| * block device payload decryption objects |
| */ |
| block->kdfhash = luks->hash_alg; |
| block->niv = qcrypto_cipher_get_iv_len(luks->cipher_alg, |
| luks->cipher_mode); |
| |
| block->ivgen = qcrypto_ivgen_new(luks->ivgen_alg, |
| luks->ivgen_cipher_alg, |
| luks->ivgen_hash_alg, |
| masterkey, |
| luks->header.master_key_len, |
| errp); |
| if (!block->ivgen) { |
| goto fail; |
| } |
| |
| if (qcrypto_block_init_cipher(block, |
| luks->cipher_alg, |
| luks->cipher_mode, |
| masterkey, |
| luks->header.master_key_len, |
| n_threads, |
| errp) < 0) { |
| goto fail; |
| } |
| } |
| |
| block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE; |
| block->payload_offset = luks->header.payload_offset_sector * |
| block->sector_size; |
| |
| return 0; |
| |
| fail: |
| qcrypto_block_free_cipher(block); |
| qcrypto_ivgen_free(block->ivgen); |
| g_free(luks); |
| return -1; |
| } |
| |
| |
| static void |
| qcrypto_block_luks_uuid_gen(uint8_t *uuidstr) |
| { |
| QemuUUID uuid; |
| qemu_uuid_generate(&uuid); |
| qemu_uuid_unparse(&uuid, (char *)uuidstr); |
| } |
| |
| static int |
| qcrypto_block_luks_create(QCryptoBlock *block, |
| QCryptoBlockCreateOptions *options, |
| const char *optprefix, |
| QCryptoBlockInitFunc initfunc, |
| QCryptoBlockWriteFunc writefunc, |
| void *opaque, |
| Error **errp) |
| { |
| QCryptoBlockLUKS *luks; |
| QCryptoBlockCreateOptionsLUKS luks_opts; |
| Error *local_err = NULL; |
| g_autofree uint8_t *masterkey = NULL; |
| size_t header_sectors; |
| size_t split_key_sectors; |
| size_t i; |
| g_autofree char *password = NULL; |
| const char *cipher_alg; |
| const char *cipher_mode; |
| const char *ivgen_alg; |
| const char *ivgen_hash_alg = NULL; |
| const char *hash_alg; |
| g_autofree char *cipher_mode_spec = NULL; |
| uint64_t iters; |
| |
| memcpy(&luks_opts, &options->u.luks, sizeof(luks_opts)); |
| if (!luks_opts.has_iter_time) { |
| luks_opts.iter_time = 2000; |
| } |
| if (!luks_opts.has_cipher_alg) { |
| luks_opts.cipher_alg = QCRYPTO_CIPHER_ALG_AES_256; |
| } |
| if (!luks_opts.has_cipher_mode) { |
| luks_opts.cipher_mode = QCRYPTO_CIPHER_MODE_XTS; |
| } |
| if (!luks_opts.has_ivgen_alg) { |
| luks_opts.ivgen_alg = QCRYPTO_IVGEN_ALG_PLAIN64; |
| } |
| if (!luks_opts.has_hash_alg) { |
| luks_opts.hash_alg = QCRYPTO_HASH_ALG_SHA256; |
| } |
| if (luks_opts.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) { |
| if (!luks_opts.has_ivgen_hash_alg) { |
| luks_opts.ivgen_hash_alg = QCRYPTO_HASH_ALG_SHA256; |
| luks_opts.has_ivgen_hash_alg = true; |
| } |
| } |
| |
| luks = g_new0(QCryptoBlockLUKS, 1); |
| block->opaque = luks; |
| |
| luks->cipher_alg = luks_opts.cipher_alg; |
| luks->cipher_mode = luks_opts.cipher_mode; |
| luks->ivgen_alg = luks_opts.ivgen_alg; |
| luks->ivgen_hash_alg = luks_opts.ivgen_hash_alg; |
| luks->hash_alg = luks_opts.hash_alg; |
| |
| |
| /* Note we're allowing ivgen_hash_alg to be set even for |
| * non-essiv iv generators that don't need a hash. It will |
| * be silently ignored, for compatibility with dm-crypt */ |
| |
| if (!options->u.luks.key_secret) { |
| error_setg(errp, "Parameter '%skey-secret' is required for cipher", |
| optprefix ? optprefix : ""); |
| goto error; |
| } |
| password = qcrypto_secret_lookup_as_utf8(luks_opts.key_secret, errp); |
| if (!password) { |
| goto error; |
| } |
| |
| |
| memcpy(luks->header.magic, qcrypto_block_luks_magic, |
| QCRYPTO_BLOCK_LUKS_MAGIC_LEN); |
| |
| /* We populate the header in native endianness initially and |
| * then convert everything to big endian just before writing |
| * it out to disk |
| */ |
| luks->header.version = QCRYPTO_BLOCK_LUKS_VERSION; |
| qcrypto_block_luks_uuid_gen(luks->header.uuid); |
| |
| cipher_alg = qcrypto_block_luks_cipher_alg_lookup(luks_opts.cipher_alg, |
| errp); |
| if (!cipher_alg) { |
| goto error; |
| } |
| |
| cipher_mode = QCryptoCipherMode_str(luks_opts.cipher_mode); |
| ivgen_alg = QCryptoIVGenAlgorithm_str(luks_opts.ivgen_alg); |
| if (luks_opts.has_ivgen_hash_alg) { |
| ivgen_hash_alg = QCryptoHashAlgorithm_str(luks_opts.ivgen_hash_alg); |
| cipher_mode_spec = g_strdup_printf("%s-%s:%s", cipher_mode, ivgen_alg, |
| ivgen_hash_alg); |
| } else { |
| cipher_mode_spec = g_strdup_printf("%s-%s", cipher_mode, ivgen_alg); |
| } |
| hash_alg = QCryptoHashAlgorithm_str(luks_opts.hash_alg); |
| |
| |
| if (strlen(cipher_alg) >= QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN) { |
| error_setg(errp, "Cipher name '%s' is too long for LUKS header", |
| cipher_alg); |
| goto error; |
| } |
| if (strlen(cipher_mode_spec) >= QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN) { |
| error_setg(errp, "Cipher mode '%s' is too long for LUKS header", |
| cipher_mode_spec); |
| goto error; |
| } |
| if (strlen(hash_alg) >= QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN) { |
| error_setg(errp, "Hash name '%s' is too long for LUKS header", |
| hash_alg); |
| goto error; |
| } |
| |
| if (luks_opts.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) { |
| luks->ivgen_cipher_alg = |
| qcrypto_block_luks_essiv_cipher(luks_opts.cipher_alg, |
| luks_opts.ivgen_hash_alg, |
| &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| goto error; |
| } |
| } else { |
| luks->ivgen_cipher_alg = luks_opts.cipher_alg; |
| } |
| |
| strcpy(luks->header.cipher_name, cipher_alg); |
| strcpy(luks->header.cipher_mode, cipher_mode_spec); |
| strcpy(luks->header.hash_spec, hash_alg); |
| |
| luks->header.master_key_len = |
| qcrypto_cipher_get_key_len(luks_opts.cipher_alg); |
| |
| if (luks_opts.cipher_mode == QCRYPTO_CIPHER_MODE_XTS) { |
| luks->header.master_key_len *= 2; |
| } |
| |
| /* Generate the salt used for hashing the master key |
| * with PBKDF later |
| */ |
| if (qcrypto_random_bytes(luks->header.master_key_salt, |
| QCRYPTO_BLOCK_LUKS_SALT_LEN, |
| errp) < 0) { |
| goto error; |
| } |
| |
| /* Generate random master key */ |
| masterkey = g_new0(uint8_t, luks->header.master_key_len); |
| if (qcrypto_random_bytes(masterkey, |
| luks->header.master_key_len, errp) < 0) { |
| goto error; |
| } |
| |
| |
| /* Setup the block device payload encryption objects */ |
| if (qcrypto_block_init_cipher(block, luks_opts.cipher_alg, |
| luks_opts.cipher_mode, masterkey, |
| luks->header.master_key_len, 1, errp) < 0) { |
| goto error; |
| } |
| |
| block->kdfhash = luks_opts.hash_alg; |
| block->niv = qcrypto_cipher_get_iv_len(luks_opts.cipher_alg, |
| luks_opts.cipher_mode); |
| block->ivgen = qcrypto_ivgen_new(luks_opts.ivgen_alg, |
| luks->ivgen_cipher_alg, |
| luks_opts.ivgen_hash_alg, |
| masterkey, luks->header.master_key_len, |
| errp); |
| |
| if (!block->ivgen) { |
| goto error; |
| } |
| |
| |
| /* Determine how many iterations we need to hash the master |
| * key, in order to have 1 second of compute time used |
| */ |
| iters = qcrypto_pbkdf2_count_iters(luks_opts.hash_alg, |
| masterkey, luks->header.master_key_len, |
| luks->header.master_key_salt, |
| QCRYPTO_BLOCK_LUKS_SALT_LEN, |
| QCRYPTO_BLOCK_LUKS_DIGEST_LEN, |
| &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| goto error; |
| } |
| |
| if (iters > (ULLONG_MAX / luks_opts.iter_time)) { |
| error_setg_errno(errp, ERANGE, |
| "PBKDF iterations %llu too large to scale", |
| (unsigned long long)iters); |
| goto error; |
| } |
| |
| /* iter_time was in millis, but count_iters reported for secs */ |
| iters = iters * luks_opts.iter_time / 1000; |
| |
| /* Why /= 8 ? That matches cryptsetup, but there's no |
| * explanation why they chose /= 8... Probably so that |
| * if all 8 keyslots are active we only spend 1 second |
| * in total time to check all keys */ |
| iters /= 8; |
| if (iters > UINT32_MAX) { |
| error_setg_errno(errp, ERANGE, |
| "PBKDF iterations %llu larger than %u", |
| (unsigned long long)iters, UINT32_MAX); |
| goto error; |
| } |
| iters = MAX(iters, QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS); |
| luks->header.master_key_iterations = iters; |
| |
| /* Hash the master key, saving the result in the LUKS |
| * header. This hash is used when opening the encrypted |
| * device to verify that the user password unlocked a |
| * valid master key |
| */ |
| if (qcrypto_pbkdf2(luks_opts.hash_alg, |
| masterkey, luks->header.master_key_len, |
| luks->header.master_key_salt, |
| QCRYPTO_BLOCK_LUKS_SALT_LEN, |
| luks->header.master_key_iterations, |
| luks->header.master_key_digest, |
| QCRYPTO_BLOCK_LUKS_DIGEST_LEN, |
| errp) < 0) { |
| goto error; |
| } |
| |
| /* start with the sector that follows the header*/ |
| header_sectors = QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET / |
| QCRYPTO_BLOCK_LUKS_SECTOR_SIZE; |
| |
| split_key_sectors = |
| qcrypto_block_luks_splitkeylen_sectors(luks, |
| header_sectors, |
| QCRYPTO_BLOCK_LUKS_STRIPES); |
| |
| for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { |
| QCryptoBlockLUKSKeySlot *slot = &luks->header.key_slots[i]; |
| slot->active = QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED; |
| |
| slot->key_offset_sector = header_sectors + i * split_key_sectors; |
| slot->stripes = QCRYPTO_BLOCK_LUKS_STRIPES; |
| } |
| |
| /* The total size of the LUKS headers is the partition header + key |
| * slot headers, rounded up to the nearest sector, combined with |
| * the size of each master key material region, also rounded up |
| * to the nearest sector */ |
| luks->header.payload_offset_sector = header_sectors + |
| QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS * split_key_sectors; |
| |
| block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE; |
| block->payload_offset = luks->header.payload_offset_sector * |
| block->sector_size; |
| |
| /* Reserve header space to match payload offset */ |
| initfunc(block, block->payload_offset, opaque, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| goto error; |
| } |
| |
| |
| /* populate the slot 0 with the password encrypted master key*/ |
| /* This will also store the header */ |
| if (qcrypto_block_luks_store_key(block, |
| 0, |
| password, |
| masterkey, |
| luks_opts.iter_time, |
| writefunc, |
| opaque, |
| errp) < 0) { |
| goto error; |
| } |
| |
| memset(masterkey, 0, luks->header.master_key_len); |
| |
| return 0; |
| |
| error: |
| if (masterkey) { |
| memset(masterkey, 0, luks->header.master_key_len); |
| } |
| |
| qcrypto_block_free_cipher(block); |
| qcrypto_ivgen_free(block->ivgen); |
| |
| g_free(luks); |
| return -1; |
| } |
| |
| |
| static int qcrypto_block_luks_get_info(QCryptoBlock *block, |
| QCryptoBlockInfo *info, |
| Error **errp) |
| { |
| QCryptoBlockLUKS *luks = block->opaque; |
| QCryptoBlockInfoLUKSSlot *slot; |
| QCryptoBlockInfoLUKSSlotList *slots = NULL, **prev = &info->u.luks.slots; |
| size_t i; |
| |
| info->u.luks.cipher_alg = luks->cipher_alg; |
| info->u.luks.cipher_mode = luks->cipher_mode; |
| info->u.luks.ivgen_alg = luks->ivgen_alg; |
| if (info->u.luks.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) { |
| info->u.luks.has_ivgen_hash_alg = true; |
| info->u.luks.ivgen_hash_alg = luks->ivgen_hash_alg; |
| } |
| info->u.luks.hash_alg = luks->hash_alg; |
| info->u.luks.payload_offset = block->payload_offset; |
| info->u.luks.master_key_iters = luks->header.master_key_iterations; |
| info->u.luks.uuid = g_strndup((const char *)luks->header.uuid, |
| sizeof(luks->header.uuid)); |
| |
| for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { |
| slots = g_new0(QCryptoBlockInfoLUKSSlotList, 1); |
| *prev = slots; |
| |
| slots->value = slot = g_new0(QCryptoBlockInfoLUKSSlot, 1); |
| slot->active = luks->header.key_slots[i].active == |
| QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED; |
| slot->key_offset = luks->header.key_slots[i].key_offset_sector |
| * QCRYPTO_BLOCK_LUKS_SECTOR_SIZE; |
| if (slot->active) { |
| slot->has_iters = true; |
| slot->iters = luks->header.key_slots[i].iterations; |
| slot->has_stripes = true; |
| slot->stripes = luks->header.key_slots[i].stripes; |
| } |
| |
| prev = &slots->next; |
| } |
| |
| return 0; |
| } |
| |
| |
| static void qcrypto_block_luks_cleanup(QCryptoBlock *block) |
| { |
| g_free(block->opaque); |
| } |
| |
| |
| static int |
| qcrypto_block_luks_decrypt(QCryptoBlock *block, |
| uint64_t offset, |
| uint8_t *buf, |
| size_t len, |
| Error **errp) |
| { |
| assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)); |
| assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)); |
| return qcrypto_block_decrypt_helper(block, |
| QCRYPTO_BLOCK_LUKS_SECTOR_SIZE, |
| offset, buf, len, errp); |
| } |
| |
| |
| static int |
| qcrypto_block_luks_encrypt(QCryptoBlock *block, |
| uint64_t offset, |
| uint8_t *buf, |
| size_t len, |
| Error **errp) |
| { |
| assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)); |
| assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)); |
| return qcrypto_block_encrypt_helper(block, |
| QCRYPTO_BLOCK_LUKS_SECTOR_SIZE, |
| offset, buf, len, errp); |
| } |
| |
| |
| const QCryptoBlockDriver qcrypto_block_driver_luks = { |
| .open = qcrypto_block_luks_open, |
| .create = qcrypto_block_luks_create, |
| .get_info = qcrypto_block_luks_get_info, |
| .cleanup = qcrypto_block_luks_cleanup, |
| .decrypt = qcrypto_block_luks_decrypt, |
| .encrypt = qcrypto_block_luks_encrypt, |
| .has_format = qcrypto_block_luks_has_format, |
| }; |
