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/bitmap.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 QCryptoBlockLUKSHeader QCryptoBlockLUKSHeader; 48 typedef struct QCryptoBlockLUKSKeySlot QCryptoBlockLUKSKeySlot; 49 50 51 /* The following constants are all defined by the LUKS spec */ 52 #define QCRYPTO_BLOCK_LUKS_VERSION 1 53 54 #define QCRYPTO_BLOCK_LUKS_MAGIC_LEN 6 55 #define QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN 32 56 #define QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN 32 57 #define QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN 32 58 #define QCRYPTO_BLOCK_LUKS_DIGEST_LEN 20 59 #define QCRYPTO_BLOCK_LUKS_SALT_LEN 32 60 #define QCRYPTO_BLOCK_LUKS_UUID_LEN 40 61 #define QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS 8 62 #define QCRYPTO_BLOCK_LUKS_STRIPES 4000 63 #define QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS 1000 64 #define QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS 1000 65 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET 4096 66 67 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED 0x0000DEAD 68 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED 0x00AC71F3 69 70 #define QCRYPTO_BLOCK_LUKS_SECTOR_SIZE 512LL 71 72 #define QCRYPTO_BLOCK_LUKS_DEFAULT_ITER_TIME_MS 2000 73 #define QCRYPTO_BLOCK_LUKS_ERASE_ITERATIONS 40 74 75 static const char qcrypto_block_luks_magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN] = { 76 'L', 'U', 'K', 'S', 0xBA, 0xBE 77 }; 78 79 /* 80 * This struct is written to disk in big-endian format, 81 * but operated upon in native-endian format. 82 */ 83 struct QCryptoBlockLUKSKeySlot { 84 /* state of keyslot, enabled/disable */ 85 uint32_t active; 86 /* iterations for PBKDF2 */ 87 uint32_t iterations; 88 /* salt for PBKDF2 */ 89 uint8_t salt[QCRYPTO_BLOCK_LUKS_SALT_LEN]; 90 /* start sector of key material */ 91 uint32_t key_offset_sector; 92 /* number of anti-forensic stripes */ 93 uint32_t stripes; 94 }; 95 96 /* 97 * This struct is written to disk in big-endian format, 98 * but operated upon in native-endian format. 99 */ 100 struct QCryptoBlockLUKSHeader { 101 /* 'L', 'U', 'K', 'S', '0xBA', '0xBE' */ 102 char magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN]; 103 104 /* LUKS version, currently 1 */ 105 uint16_t version; 106 107 /* cipher name specification (aes, etc) */ 108 char cipher_name[QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN]; 109 110 /* cipher mode specification (cbc-plain, xts-essiv:sha256, etc) */ 111 char cipher_mode[QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN]; 112 113 /* hash specification (sha256, etc) */ 114 char hash_spec[QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN]; 115 116 /* start offset of the volume data (in 512 byte sectors) */ 117 uint32_t payload_offset_sector; 118 119 /* Number of key bytes */ 120 uint32_t master_key_len; 121 122 /* master key checksum after PBKDF2 */ 123 uint8_t master_key_digest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN]; 124 125 /* salt for master key PBKDF2 */ 126 uint8_t master_key_salt[QCRYPTO_BLOCK_LUKS_SALT_LEN]; 127 128 /* iterations for master key PBKDF2 */ 129 uint32_t master_key_iterations; 130 131 /* UUID of the partition in standard ASCII representation */ 132 uint8_t uuid[QCRYPTO_BLOCK_LUKS_UUID_LEN]; 133 134 /* key slots */ 135 QCryptoBlockLUKSKeySlot key_slots[QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS]; 136 }; 137 138 139 void 140 qcrypto_block_luks_to_disk_endian(QCryptoBlockLUKSHeader *hdr); 141 void 142 qcrypto_block_luks_from_disk_endian(QCryptoBlockLUKSHeader *hdr); 143