crypto/block-luks-priv.h

   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 "qapi/error.h"
  22 #include "qemu/bswap.h"
  23
  24 #include "block-luks.h"
  25
  26 #include "crypto/hash.h"
  27 #include "crypto/afsplit.h"
  28 #include "crypto/pbkdf.h"
  29 #include "crypto/secret.h"
  30 #include "crypto/random.h"
  31 #include "qemu/uuid.h"
  32
  33 #include "qemu/bitmap.h"
  34
  35 /*
  36  * Reference for the LUKS format implemented here is
  37  *
  38  *   docs/on-disk-format.pdf
  39  *
  40  * in 'cryptsetup' package source code
  41  *
  42  * This file implements the 1.2.1 specification, dated
  43  * Oct 16, 2011.
  44  */
  45
  46 typedef struct QCryptoBlockLUKSHeader QCryptoBlockLUKSHeader;
  47 typedef struct QCryptoBlockLUKSKeySlot QCryptoBlockLUKSKeySlot;
  48
  49
  50 /* The following constants are all defined by the LUKS spec */
  51 #define QCRYPTO_BLOCK_LUKS_VERSION 1
  52
  53 #define QCRYPTO_BLOCK_LUKS_MAGIC_LEN 6
  54 #define QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN 32
  55 #define QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN 32
  56 #define QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN 32
  57 #define QCRYPTO_BLOCK_LUKS_DIGEST_LEN 20
  58 #define QCRYPTO_BLOCK_LUKS_SALT_LEN 32
  59 #define QCRYPTO_BLOCK_LUKS_UUID_LEN 40
  60 #define QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS 8
  61 #define QCRYPTO_BLOCK_LUKS_STRIPES 4000
  62 #define QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS 1000
  63 #define QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS 1000
  64 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET 4096
  65
  66 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED 0x0000DEAD
  67 #define QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED 0x00AC71F3
  68
  69 #define QCRYPTO_BLOCK_LUKS_SECTOR_SIZE 512LL
  70
  71 #define QCRYPTO_BLOCK_LUKS_DEFAULT_ITER_TIME_MS 2000
  72 #define QCRYPTO_BLOCK_LUKS_ERASE_ITERATIONS 40
  73
  74 static const char qcrypto_block_luks_magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN] = {
  75     'L', 'U', 'K', 'S', 0xBA, 0xBE
  76 };
  77
  78 /*
  79  * This struct is written to disk in big-endian format,
  80  * but operated upon in native-endian format.
  81  */
  82 struct QCryptoBlockLUKSKeySlot {
  83     /* state of keyslot, enabled/disable */
  84     uint32_t active;
  85     /* iterations for PBKDF2 */
  86     uint32_t iterations;
  87     /* salt for PBKDF2 */
  88     uint8_t salt[QCRYPTO_BLOCK_LUKS_SALT_LEN];
  89     /* start sector of key material */
  90     uint32_t key_offset_sector;
  91     /* number of anti-forensic stripes */
  92     uint32_t stripes;
  93 };
  94
  95 /*
  96  * This struct is written to disk in big-endian format,
  97  * but operated upon in native-endian format.
  98  */
  99 struct QCryptoBlockLUKSHeader {
 100     /* 'L', 'U', 'K', 'S', '0xBA', '0xBE' */
 101     char magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN];
 102
 103     /* LUKS version, currently 1 */
 104     uint16_t version;
 105
 106     /* cipher name specification (aes, etc) */
 107     char cipher_name[QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN];
 108
 109     /* cipher mode specification (cbc-plain, xts-essiv:sha256, etc) */
 110     char cipher_mode[QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN];
 111
 112     /* hash specification (sha256, etc) */
 113     char hash_spec[QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN];
 114
 115     /* start offset of the volume data (in 512 byte sectors) */
 116     uint32_t payload_offset_sector;
 117
 118     /* Number of key bytes */
 119     uint32_t master_key_len;
 120
 121     /* master key checksum after PBKDF2 */
 122     uint8_t master_key_digest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN];
 123
 124     /* salt for master key PBKDF2 */
 125     uint8_t master_key_salt[QCRYPTO_BLOCK_LUKS_SALT_LEN];
 126
 127     /* iterations for master key PBKDF2 */
 128     uint32_t master_key_iterations;
 129
 130     /* UUID of the partition in standard ASCII representation */
 131     uint8_t uuid[QCRYPTO_BLOCK_LUKS_UUID_LEN];
 132
 133     /* key slots */
 134     QCryptoBlockLUKSKeySlot key_slots[QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS];
 135 };
 136
 137
 138 void
 139 qcrypto_block_luks_to_disk_endian(QCryptoBlockLUKSHeader *hdr);
 140 void
 141 qcrypto_block_luks_from_disk_endian(QCryptoBlockLUKSHeader *hdr);