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/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);