xref: /openbmc/qemu/crypto/block-luks-priv.h (revision f4124f83)
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);
142