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 "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 #include "qemu/bitmap.h"
  36
  37 /*
  38  * Reference for the LUKS format implemented here is
  39  *
  40  *   docs/on-disk-format.pdf
  41  *
  42  * in 'cryptsetup' package source code
  43  *
  44  * This file implements the 1.2.1 specification, dated
  45  * Oct 16, 2011.
  46  */
  47
  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 #define QCRYPTO_BLOCK_LUKS_DEFAULT_ITER_TIME_MS 2000
  74 #define QCRYPTO_BLOCK_LUKS_ERASE_ITERATIONS 40
  75
  76 static const char qcrypto_block_luks_magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN] = {
  77     'L', 'U', 'K', 'S', 0xBA, 0xBE
  78 };
  79
  80 /*
  81  * This struct is written to disk in big-endian format,
  82  * but operated upon in native-endian format.
  83  */
  84 struct QCryptoBlockLUKSKeySlot {
  85     /* state of keyslot, enabled/disable */
  86     uint32_t active;
  87     /* iterations for PBKDF2 */
  88     uint32_t iterations;
  89     /* salt for PBKDF2 */
  90     uint8_t salt[QCRYPTO_BLOCK_LUKS_SALT_LEN];
  91     /* start sector of key material */
  92     uint32_t key_offset_sector;
  93     /* number of anti-forensic stripes */
  94     uint32_t stripes;
  95 };
  96
  97 /*
  98  * This struct is written to disk in big-endian format,
  99  * but operated upon in native-endian format.
 100  */
 101 struct QCryptoBlockLUKSHeader {
 102     /* 'L', 'U', 'K', 'S', '0xBA', '0xBE' */
 103     char magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN];
 104
 105     /* LUKS version, currently 1 */
 106     uint16_t version;
 107
 108     /* cipher name specification (aes, etc) */
 109     char cipher_name[QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN];
 110
 111     /* cipher mode specification (cbc-plain, xts-essiv:sha256, etc) */
 112     char cipher_mode[QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN];
 113
 114     /* hash specification (sha256, etc) */
 115     char hash_spec[QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN];
 116
 117     /* start offset of the volume data (in 512 byte sectors) */
 118     uint32_t payload_offset_sector;
 119
 120     /* Number of key bytes */
 121     uint32_t master_key_len;
 122
 123     /* master key checksum after PBKDF2 */
 124     uint8_t master_key_digest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN];
 125
 126     /* salt for master key PBKDF2 */
 127     uint8_t master_key_salt[QCRYPTO_BLOCK_LUKS_SALT_LEN];
 128
 129     /* iterations for master key PBKDF2 */
 130     uint32_t master_key_iterations;
 131
 132     /* UUID of the partition in standard ASCII representation */
 133     uint8_t uuid[QCRYPTO_BLOCK_LUKS_UUID_LEN];
 134
 135     /* key slots */
 136     QCryptoBlockLUKSKeySlot key_slots[QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS];
 137 };
 138
 139
 140 void
 141 qcrypto_block_luks_to_disk_endian(QCryptoBlockLUKSHeader *hdr);
 142 void
 143 qcrypto_block_luks_from_disk_endian(QCryptoBlockLUKSHeader *hdr);