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3e308f20 DB |
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 | |
b7cbb874 | 9 | * version 2.1 of the License, or (at your option) any later version. |
3e308f20 DB |
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" | |
da34e65c | 22 | #include "qapi/error.h" |
58369e22 | 23 | #include "qemu/bswap.h" |
3e308f20 | 24 | |
986bc8de | 25 | #include "block-luks.h" |
3e308f20 DB |
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" | |
2ef950f9 | 32 | #include "qemu/uuid.h" |
3e308f20 DB |
33 | |
34 | #include "qemu/coroutine.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 QCryptoBlockLUKS QCryptoBlockLUKS; | |
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 | static const char qcrypto_block_luks_magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN] = { | |
74 | 'L', 'U', 'K', 'S', 0xBA, 0xBE | |
75 | }; | |
76 | ||
77 | typedef struct QCryptoBlockLUKSNameMap QCryptoBlockLUKSNameMap; | |
78 | struct QCryptoBlockLUKSNameMap { | |
79 | const char *name; | |
80 | int id; | |
81 | }; | |
82 | ||
83 | typedef struct QCryptoBlockLUKSCipherSizeMap QCryptoBlockLUKSCipherSizeMap; | |
84 | struct QCryptoBlockLUKSCipherSizeMap { | |
85 | uint32_t key_bytes; | |
86 | int id; | |
87 | }; | |
88 | typedef struct QCryptoBlockLUKSCipherNameMap QCryptoBlockLUKSCipherNameMap; | |
89 | struct QCryptoBlockLUKSCipherNameMap { | |
90 | const char *name; | |
91 | const QCryptoBlockLUKSCipherSizeMap *sizes; | |
92 | }; | |
93 | ||
94 | ||
95 | static const QCryptoBlockLUKSCipherSizeMap | |
96 | qcrypto_block_luks_cipher_size_map_aes[] = { | |
97 | { 16, QCRYPTO_CIPHER_ALG_AES_128 }, | |
98 | { 24, QCRYPTO_CIPHER_ALG_AES_192 }, | |
99 | { 32, QCRYPTO_CIPHER_ALG_AES_256 }, | |
100 | { 0, 0 }, | |
101 | }; | |
102 | ||
103 | static const QCryptoBlockLUKSCipherSizeMap | |
104 | qcrypto_block_luks_cipher_size_map_cast5[] = { | |
105 | { 16, QCRYPTO_CIPHER_ALG_CAST5_128 }, | |
106 | { 0, 0 }, | |
107 | }; | |
108 | ||
109 | static const QCryptoBlockLUKSCipherSizeMap | |
110 | qcrypto_block_luks_cipher_size_map_serpent[] = { | |
111 | { 16, QCRYPTO_CIPHER_ALG_SERPENT_128 }, | |
112 | { 24, QCRYPTO_CIPHER_ALG_SERPENT_192 }, | |
113 | { 32, QCRYPTO_CIPHER_ALG_SERPENT_256 }, | |
114 | { 0, 0 }, | |
115 | }; | |
116 | ||
117 | static const QCryptoBlockLUKSCipherSizeMap | |
118 | qcrypto_block_luks_cipher_size_map_twofish[] = { | |
119 | { 16, QCRYPTO_CIPHER_ALG_TWOFISH_128 }, | |
120 | { 24, QCRYPTO_CIPHER_ALG_TWOFISH_192 }, | |
121 | { 32, QCRYPTO_CIPHER_ALG_TWOFISH_256 }, | |
122 | { 0, 0 }, | |
123 | }; | |
124 | ||
125 | static const QCryptoBlockLUKSCipherNameMap | |
126 | qcrypto_block_luks_cipher_name_map[] = { | |
127 | { "aes", qcrypto_block_luks_cipher_size_map_aes }, | |
128 | { "cast5", qcrypto_block_luks_cipher_size_map_cast5 }, | |
129 | { "serpent", qcrypto_block_luks_cipher_size_map_serpent }, | |
130 | { "twofish", qcrypto_block_luks_cipher_size_map_twofish }, | |
131 | }; | |
132 | ||
133 | ||
134 | /* | |
135 | * This struct is written to disk in big-endian format, | |
136 | * but operated upon in native-endian format. | |
137 | */ | |
138 | struct QCryptoBlockLUKSKeySlot { | |
139 | /* state of keyslot, enabled/disable */ | |
140 | uint32_t active; | |
141 | /* iterations for PBKDF2 */ | |
142 | uint32_t iterations; | |
143 | /* salt for PBKDF2 */ | |
144 | uint8_t salt[QCRYPTO_BLOCK_LUKS_SALT_LEN]; | |
145 | /* start sector of key material */ | |
146 | uint32_t key_offset; | |
147 | /* number of anti-forensic stripes */ | |
148 | uint32_t stripes; | |
5993e3be | 149 | }; |
3e308f20 DB |
150 | |
151 | QEMU_BUILD_BUG_ON(sizeof(struct QCryptoBlockLUKSKeySlot) != 48); | |
152 | ||
153 | ||
154 | /* | |
155 | * This struct is written to disk in big-endian format, | |
156 | * but operated upon in native-endian format. | |
157 | */ | |
158 | struct QCryptoBlockLUKSHeader { | |
159 | /* 'L', 'U', 'K', 'S', '0xBA', '0xBE' */ | |
160 | char magic[QCRYPTO_BLOCK_LUKS_MAGIC_LEN]; | |
161 | ||
162 | /* LUKS version, currently 1 */ | |
163 | uint16_t version; | |
164 | ||
165 | /* cipher name specification (aes, etc) */ | |
166 | char cipher_name[QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN]; | |
167 | ||
168 | /* cipher mode specification (cbc-plain, xts-essiv:sha256, etc) */ | |
169 | char cipher_mode[QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN]; | |
170 | ||
171 | /* hash specification (sha256, etc) */ | |
172 | char hash_spec[QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN]; | |
173 | ||
174 | /* start offset of the volume data (in 512 byte sectors) */ | |
175 | uint32_t payload_offset; | |
176 | ||
177 | /* Number of key bytes */ | |
178 | uint32_t key_bytes; | |
179 | ||
180 | /* master key checksum after PBKDF2 */ | |
181 | uint8_t master_key_digest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN]; | |
182 | ||
183 | /* salt for master key PBKDF2 */ | |
184 | uint8_t master_key_salt[QCRYPTO_BLOCK_LUKS_SALT_LEN]; | |
185 | ||
186 | /* iterations for master key PBKDF2 */ | |
187 | uint32_t master_key_iterations; | |
188 | ||
189 | /* UUID of the partition in standard ASCII representation */ | |
190 | uint8_t uuid[QCRYPTO_BLOCK_LUKS_UUID_LEN]; | |
191 | ||
192 | /* key slots */ | |
193 | QCryptoBlockLUKSKeySlot key_slots[QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS]; | |
5993e3be | 194 | }; |
3e308f20 DB |
195 | |
196 | QEMU_BUILD_BUG_ON(sizeof(struct QCryptoBlockLUKSHeader) != 592); | |
197 | ||
198 | ||
199 | struct QCryptoBlockLUKS { | |
200 | QCryptoBlockLUKSHeader header; | |
40c85028 DB |
201 | |
202 | /* Cache parsed versions of what's in header fields, | |
203 | * as we can't rely on QCryptoBlock.cipher being | |
204 | * non-NULL */ | |
205 | QCryptoCipherAlgorithm cipher_alg; | |
206 | QCryptoCipherMode cipher_mode; | |
207 | QCryptoIVGenAlgorithm ivgen_alg; | |
208 | QCryptoHashAlgorithm ivgen_hash_alg; | |
209 | QCryptoHashAlgorithm hash_alg; | |
3e308f20 DB |
210 | }; |
211 | ||
212 | ||
213 | static int qcrypto_block_luks_cipher_name_lookup(const char *name, | |
214 | QCryptoCipherMode mode, | |
215 | uint32_t key_bytes, | |
216 | Error **errp) | |
217 | { | |
218 | const QCryptoBlockLUKSCipherNameMap *map = | |
219 | qcrypto_block_luks_cipher_name_map; | |
220 | size_t maplen = G_N_ELEMENTS(qcrypto_block_luks_cipher_name_map); | |
221 | size_t i, j; | |
222 | ||
223 | if (mode == QCRYPTO_CIPHER_MODE_XTS) { | |
224 | key_bytes /= 2; | |
225 | } | |
226 | ||
227 | for (i = 0; i < maplen; i++) { | |
228 | if (!g_str_equal(map[i].name, name)) { | |
229 | continue; | |
230 | } | |
231 | for (j = 0; j < map[i].sizes[j].key_bytes; j++) { | |
232 | if (map[i].sizes[j].key_bytes == key_bytes) { | |
233 | return map[i].sizes[j].id; | |
234 | } | |
235 | } | |
236 | } | |
237 | ||
238 | error_setg(errp, "Algorithm %s with key size %d bytes not supported", | |
239 | name, key_bytes); | |
240 | return 0; | |
241 | } | |
242 | ||
243 | static const char * | |
244 | qcrypto_block_luks_cipher_alg_lookup(QCryptoCipherAlgorithm alg, | |
245 | Error **errp) | |
246 | { | |
247 | const QCryptoBlockLUKSCipherNameMap *map = | |
248 | qcrypto_block_luks_cipher_name_map; | |
249 | size_t maplen = G_N_ELEMENTS(qcrypto_block_luks_cipher_name_map); | |
250 | size_t i, j; | |
251 | for (i = 0; i < maplen; i++) { | |
252 | for (j = 0; j < map[i].sizes[j].key_bytes; j++) { | |
253 | if (map[i].sizes[j].id == alg) { | |
254 | return map[i].name; | |
255 | } | |
256 | } | |
257 | } | |
258 | ||
259 | error_setg(errp, "Algorithm '%s' not supported", | |
977c736f | 260 | QCryptoCipherAlgorithm_str(alg)); |
3e308f20 DB |
261 | return NULL; |
262 | } | |
263 | ||
264 | /* XXX replace with qapi_enum_parse() in future, when we can | |
265 | * make that function emit a more friendly error message */ | |
266 | static int qcrypto_block_luks_name_lookup(const char *name, | |
f7abe0ec | 267 | const QEnumLookup *map, |
3e308f20 DB |
268 | const char *type, |
269 | Error **errp) | |
270 | { | |
9ae33079 | 271 | int ret = qapi_enum_parse(map, name, -1, NULL); |
3e308f20 | 272 | |
9ae33079 MA |
273 | if (ret < 0) { |
274 | error_setg(errp, "%s %s not supported", type, name); | |
275 | return 0; | |
276 | } | |
277 | return ret; | |
3e308f20 DB |
278 | } |
279 | ||
280 | #define qcrypto_block_luks_cipher_mode_lookup(name, errp) \ | |
281 | qcrypto_block_luks_name_lookup(name, \ | |
f7abe0ec | 282 | &QCryptoCipherMode_lookup, \ |
3e308f20 DB |
283 | "Cipher mode", \ |
284 | errp) | |
285 | ||
286 | #define qcrypto_block_luks_hash_name_lookup(name, errp) \ | |
287 | qcrypto_block_luks_name_lookup(name, \ | |
f7abe0ec | 288 | &QCryptoHashAlgorithm_lookup, \ |
3e308f20 DB |
289 | "Hash algorithm", \ |
290 | errp) | |
291 | ||
292 | #define qcrypto_block_luks_ivgen_name_lookup(name, errp) \ | |
293 | qcrypto_block_luks_name_lookup(name, \ | |
f7abe0ec | 294 | &QCryptoIVGenAlgorithm_lookup, \ |
3e308f20 DB |
295 | "IV generator", \ |
296 | errp) | |
297 | ||
298 | ||
299 | static bool | |
300 | qcrypto_block_luks_has_format(const uint8_t *buf, | |
301 | size_t buf_size) | |
302 | { | |
303 | const QCryptoBlockLUKSHeader *luks_header = (const void *)buf; | |
304 | ||
305 | if (buf_size >= offsetof(QCryptoBlockLUKSHeader, cipher_name) && | |
306 | memcmp(luks_header->magic, qcrypto_block_luks_magic, | |
307 | QCRYPTO_BLOCK_LUKS_MAGIC_LEN) == 0 && | |
308 | be16_to_cpu(luks_header->version) == QCRYPTO_BLOCK_LUKS_VERSION) { | |
309 | return true; | |
310 | } else { | |
311 | return false; | |
312 | } | |
313 | } | |
314 | ||
315 | ||
316 | /** | |
317 | * Deal with a quirk of dm-crypt usage of ESSIV. | |
318 | * | |
319 | * When calculating ESSIV IVs, the cipher length used by ESSIV | |
320 | * may be different from the cipher length used for the block | |
321 | * encryption, becauses dm-crypt uses the hash digest length | |
322 | * as the key size. ie, if you have AES 128 as the block cipher | |
323 | * and SHA 256 as ESSIV hash, then ESSIV will use AES 256 as | |
324 | * the cipher since that gets a key length matching the digest | |
325 | * size, not AES 128 with truncated digest as might be imagined | |
326 | */ | |
327 | static QCryptoCipherAlgorithm | |
328 | qcrypto_block_luks_essiv_cipher(QCryptoCipherAlgorithm cipher, | |
329 | QCryptoHashAlgorithm hash, | |
330 | Error **errp) | |
331 | { | |
332 | size_t digestlen = qcrypto_hash_digest_len(hash); | |
333 | size_t keylen = qcrypto_cipher_get_key_len(cipher); | |
334 | if (digestlen == keylen) { | |
335 | return cipher; | |
336 | } | |
337 | ||
338 | switch (cipher) { | |
339 | case QCRYPTO_CIPHER_ALG_AES_128: | |
340 | case QCRYPTO_CIPHER_ALG_AES_192: | |
341 | case QCRYPTO_CIPHER_ALG_AES_256: | |
342 | if (digestlen == qcrypto_cipher_get_key_len( | |
343 | QCRYPTO_CIPHER_ALG_AES_128)) { | |
344 | return QCRYPTO_CIPHER_ALG_AES_128; | |
345 | } else if (digestlen == qcrypto_cipher_get_key_len( | |
346 | QCRYPTO_CIPHER_ALG_AES_192)) { | |
347 | return QCRYPTO_CIPHER_ALG_AES_192; | |
348 | } else if (digestlen == qcrypto_cipher_get_key_len( | |
349 | QCRYPTO_CIPHER_ALG_AES_256)) { | |
350 | return QCRYPTO_CIPHER_ALG_AES_256; | |
351 | } else { | |
352 | error_setg(errp, "No AES cipher with key size %zu available", | |
353 | digestlen); | |
354 | return 0; | |
355 | } | |
356 | break; | |
357 | case QCRYPTO_CIPHER_ALG_SERPENT_128: | |
358 | case QCRYPTO_CIPHER_ALG_SERPENT_192: | |
359 | case QCRYPTO_CIPHER_ALG_SERPENT_256: | |
360 | if (digestlen == qcrypto_cipher_get_key_len( | |
361 | QCRYPTO_CIPHER_ALG_SERPENT_128)) { | |
362 | return QCRYPTO_CIPHER_ALG_SERPENT_128; | |
363 | } else if (digestlen == qcrypto_cipher_get_key_len( | |
364 | QCRYPTO_CIPHER_ALG_SERPENT_192)) { | |
365 | return QCRYPTO_CIPHER_ALG_SERPENT_192; | |
366 | } else if (digestlen == qcrypto_cipher_get_key_len( | |
367 | QCRYPTO_CIPHER_ALG_SERPENT_256)) { | |
368 | return QCRYPTO_CIPHER_ALG_SERPENT_256; | |
369 | } else { | |
370 | error_setg(errp, "No Serpent cipher with key size %zu available", | |
371 | digestlen); | |
372 | return 0; | |
373 | } | |
374 | break; | |
375 | case QCRYPTO_CIPHER_ALG_TWOFISH_128: | |
376 | case QCRYPTO_CIPHER_ALG_TWOFISH_192: | |
377 | case QCRYPTO_CIPHER_ALG_TWOFISH_256: | |
378 | if (digestlen == qcrypto_cipher_get_key_len( | |
379 | QCRYPTO_CIPHER_ALG_TWOFISH_128)) { | |
380 | return QCRYPTO_CIPHER_ALG_TWOFISH_128; | |
381 | } else if (digestlen == qcrypto_cipher_get_key_len( | |
382 | QCRYPTO_CIPHER_ALG_TWOFISH_192)) { | |
383 | return QCRYPTO_CIPHER_ALG_TWOFISH_192; | |
384 | } else if (digestlen == qcrypto_cipher_get_key_len( | |
385 | QCRYPTO_CIPHER_ALG_TWOFISH_256)) { | |
386 | return QCRYPTO_CIPHER_ALG_TWOFISH_256; | |
387 | } else { | |
388 | error_setg(errp, "No Twofish cipher with key size %zu available", | |
389 | digestlen); | |
390 | return 0; | |
391 | } | |
392 | break; | |
393 | default: | |
394 | error_setg(errp, "Cipher %s not supported with essiv", | |
977c736f | 395 | QCryptoCipherAlgorithm_str(cipher)); |
3e308f20 DB |
396 | return 0; |
397 | } | |
398 | } | |
399 | ||
400 | /* | |
401 | * Given a key slot, and user password, this will attempt to unlock | |
402 | * the master encryption key from the key slot. | |
403 | * | |
404 | * Returns: | |
405 | * 0 if the key slot is disabled, or key could not be decrypted | |
406 | * with the provided password | |
407 | * 1 if the key slot is enabled, and key decrypted successfully | |
408 | * with the provided password | |
409 | * -1 if a fatal error occurred loading the key | |
410 | */ | |
411 | static int | |
412 | qcrypto_block_luks_load_key(QCryptoBlock *block, | |
413 | QCryptoBlockLUKSKeySlot *slot, | |
414 | const char *password, | |
415 | QCryptoCipherAlgorithm cipheralg, | |
416 | QCryptoCipherMode ciphermode, | |
417 | QCryptoHashAlgorithm hash, | |
418 | QCryptoIVGenAlgorithm ivalg, | |
419 | QCryptoCipherAlgorithm ivcipheralg, | |
420 | QCryptoHashAlgorithm ivhash, | |
421 | uint8_t *masterkey, | |
422 | size_t masterkeylen, | |
423 | QCryptoBlockReadFunc readfunc, | |
424 | void *opaque, | |
425 | Error **errp) | |
426 | { | |
427 | QCryptoBlockLUKS *luks = block->opaque; | |
57b9f113 | 428 | g_autofree uint8_t *splitkey = NULL; |
3e308f20 | 429 | size_t splitkeylen; |
57b9f113 | 430 | g_autofree uint8_t *possiblekey = NULL; |
3e308f20 | 431 | ssize_t rv; |
57b9f113 | 432 | g_autoptr(QCryptoCipher) cipher = NULL; |
3e308f20 | 433 | uint8_t keydigest[QCRYPTO_BLOCK_LUKS_DIGEST_LEN]; |
57b9f113 | 434 | g_autoptr(QCryptoIVGen) ivgen = NULL; |
3e308f20 DB |
435 | size_t niv; |
436 | ||
437 | if (slot->active != QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED) { | |
438 | return 0; | |
439 | } | |
440 | ||
441 | splitkeylen = masterkeylen * slot->stripes; | |
442 | splitkey = g_new0(uint8_t, splitkeylen); | |
443 | possiblekey = g_new0(uint8_t, masterkeylen); | |
444 | ||
445 | /* | |
446 | * The user password is used to generate a (possible) | |
447 | * decryption key. This may or may not successfully | |
448 | * decrypt the master key - we just blindly assume | |
449 | * the key is correct and validate the results of | |
450 | * decryption later. | |
451 | */ | |
452 | if (qcrypto_pbkdf2(hash, | |
453 | (const uint8_t *)password, strlen(password), | |
454 | slot->salt, QCRYPTO_BLOCK_LUKS_SALT_LEN, | |
455 | slot->iterations, | |
456 | possiblekey, masterkeylen, | |
457 | errp) < 0) { | |
57b9f113 | 458 | return -1; |
3e308f20 DB |
459 | } |
460 | ||
461 | /* | |
462 | * We need to read the master key material from the | |
463 | * LUKS key material header. What we're reading is | |
464 | * not the raw master key, but rather the data after | |
465 | * it has been passed through AFSplit and the result | |
466 | * then encrypted. | |
467 | */ | |
468 | rv = readfunc(block, | |
469 | slot->key_offset * QCRYPTO_BLOCK_LUKS_SECTOR_SIZE, | |
470 | splitkey, splitkeylen, | |
e4a3507e | 471 | opaque, |
37509233 | 472 | errp); |
3e308f20 | 473 | if (rv < 0) { |
57b9f113 | 474 | return -1; |
3e308f20 DB |
475 | } |
476 | ||
477 | ||
478 | /* Setup the cipher/ivgen that we'll use to try to decrypt | |
479 | * the split master key material */ | |
480 | cipher = qcrypto_cipher_new(cipheralg, ciphermode, | |
481 | possiblekey, masterkeylen, | |
482 | errp); | |
483 | if (!cipher) { | |
57b9f113 | 484 | return -1; |
3e308f20 DB |
485 | } |
486 | ||
487 | niv = qcrypto_cipher_get_iv_len(cipheralg, | |
488 | ciphermode); | |
489 | ivgen = qcrypto_ivgen_new(ivalg, | |
490 | ivcipheralg, | |
491 | ivhash, | |
492 | possiblekey, masterkeylen, | |
493 | errp); | |
494 | if (!ivgen) { | |
57b9f113 | 495 | return -1; |
3e308f20 DB |
496 | } |
497 | ||
498 | ||
499 | /* | |
500 | * The master key needs to be decrypted in the same | |
501 | * way that the block device payload will be decrypted | |
502 | * later. In particular we'll be using the IV generator | |
503 | * to reset the encryption cipher every time the master | |
504 | * key crosses a sector boundary. | |
505 | */ | |
0270417c VSO |
506 | if (qcrypto_block_cipher_decrypt_helper(cipher, |
507 | niv, | |
508 | ivgen, | |
509 | QCRYPTO_BLOCK_LUKS_SECTOR_SIZE, | |
510 | 0, | |
511 | splitkey, | |
512 | splitkeylen, | |
513 | errp) < 0) { | |
57b9f113 | 514 | return -1; |
3e308f20 DB |
515 | } |
516 | ||
517 | /* | |
518 | * Now we've decrypted the split master key, join | |
519 | * it back together to get the actual master key. | |
520 | */ | |
521 | if (qcrypto_afsplit_decode(hash, | |
522 | masterkeylen, | |
523 | slot->stripes, | |
524 | splitkey, | |
525 | masterkey, | |
526 | errp) < 0) { | |
57b9f113 | 527 | return -1; |
3e308f20 DB |
528 | } |
529 | ||
530 | ||
531 | /* | |
532 | * We still don't know that the masterkey we got is valid, | |
533 | * because we just blindly assumed the user's password | |
534 | * was correct. This is where we now verify it. We are | |
535 | * creating a hash of the master key using PBKDF and | |
536 | * then comparing that to the hash stored in the key slot | |
537 | * header | |
538 | */ | |
539 | if (qcrypto_pbkdf2(hash, | |
540 | masterkey, masterkeylen, | |
541 | luks->header.master_key_salt, | |
542 | QCRYPTO_BLOCK_LUKS_SALT_LEN, | |
543 | luks->header.master_key_iterations, | |
544 | keydigest, G_N_ELEMENTS(keydigest), | |
545 | errp) < 0) { | |
57b9f113 | 546 | return -1; |
3e308f20 DB |
547 | } |
548 | ||
549 | if (memcmp(keydigest, luks->header.master_key_digest, | |
550 | QCRYPTO_BLOCK_LUKS_DIGEST_LEN) == 0) { | |
551 | /* Success, we got the right master key */ | |
57b9f113 | 552 | return 1; |
3e308f20 DB |
553 | } |
554 | ||
555 | /* Fail, user's password was not valid for this key slot, | |
556 | * tell caller to try another slot */ | |
57b9f113 | 557 | return 0; |
3e308f20 DB |
558 | } |
559 | ||
560 | ||
561 | /* | |
562 | * Given a user password, this will iterate over all key | |
563 | * slots and try to unlock each active key slot using the | |
564 | * password until it successfully obtains a master key. | |
565 | * | |
566 | * Returns 0 if a key was loaded, -1 if no keys could be loaded | |
567 | */ | |
568 | static int | |
569 | qcrypto_block_luks_find_key(QCryptoBlock *block, | |
570 | const char *password, | |
571 | QCryptoCipherAlgorithm cipheralg, | |
572 | QCryptoCipherMode ciphermode, | |
573 | QCryptoHashAlgorithm hash, | |
574 | QCryptoIVGenAlgorithm ivalg, | |
575 | QCryptoCipherAlgorithm ivcipheralg, | |
576 | QCryptoHashAlgorithm ivhash, | |
577 | uint8_t **masterkey, | |
578 | size_t *masterkeylen, | |
579 | QCryptoBlockReadFunc readfunc, | |
580 | void *opaque, | |
581 | Error **errp) | |
582 | { | |
583 | QCryptoBlockLUKS *luks = block->opaque; | |
584 | size_t i; | |
585 | int rv; | |
586 | ||
587 | *masterkey = g_new0(uint8_t, luks->header.key_bytes); | |
588 | *masterkeylen = luks->header.key_bytes; | |
589 | ||
590 | for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { | |
591 | rv = qcrypto_block_luks_load_key(block, | |
592 | &luks->header.key_slots[i], | |
593 | password, | |
594 | cipheralg, | |
595 | ciphermode, | |
596 | hash, | |
597 | ivalg, | |
598 | ivcipheralg, | |
599 | ivhash, | |
600 | *masterkey, | |
601 | *masterkeylen, | |
602 | readfunc, | |
603 | opaque, | |
604 | errp); | |
605 | if (rv < 0) { | |
606 | goto error; | |
607 | } | |
608 | if (rv == 1) { | |
609 | return 0; | |
610 | } | |
611 | } | |
612 | ||
613 | error_setg(errp, "Invalid password, cannot unlock any keyslot"); | |
614 | ||
615 | error: | |
616 | g_free(*masterkey); | |
617 | *masterkey = NULL; | |
618 | *masterkeylen = 0; | |
619 | return -1; | |
620 | } | |
621 | ||
622 | ||
623 | static int | |
624 | qcrypto_block_luks_open(QCryptoBlock *block, | |
625 | QCryptoBlockOpenOptions *options, | |
1cd9a787 | 626 | const char *optprefix, |
3e308f20 DB |
627 | QCryptoBlockReadFunc readfunc, |
628 | void *opaque, | |
629 | unsigned int flags, | |
c972fa12 | 630 | size_t n_threads, |
3e308f20 DB |
631 | Error **errp) |
632 | { | |
633 | QCryptoBlockLUKS *luks; | |
634 | Error *local_err = NULL; | |
635 | int ret = 0; | |
636 | size_t i; | |
637 | ssize_t rv; | |
57b9f113 | 638 | g_autofree uint8_t *masterkey = NULL; |
3e308f20 DB |
639 | size_t masterkeylen; |
640 | char *ivgen_name, *ivhash_name; | |
641 | QCryptoCipherMode ciphermode; | |
642 | QCryptoCipherAlgorithm cipheralg; | |
643 | QCryptoIVGenAlgorithm ivalg; | |
644 | QCryptoCipherAlgorithm ivcipheralg; | |
645 | QCryptoHashAlgorithm hash; | |
646 | QCryptoHashAlgorithm ivhash; | |
57b9f113 | 647 | g_autofree char *password = NULL; |
3e308f20 DB |
648 | |
649 | if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) { | |
650 | if (!options->u.luks.key_secret) { | |
1cd9a787 DB |
651 | error_setg(errp, "Parameter '%skey-secret' is required for cipher", |
652 | optprefix ? optprefix : ""); | |
3e308f20 DB |
653 | return -1; |
654 | } | |
655 | password = qcrypto_secret_lookup_as_utf8( | |
656 | options->u.luks.key_secret, errp); | |
657 | if (!password) { | |
658 | return -1; | |
659 | } | |
660 | } | |
661 | ||
662 | luks = g_new0(QCryptoBlockLUKS, 1); | |
663 | block->opaque = luks; | |
664 | ||
665 | /* Read the entire LUKS header, minus the key material from | |
666 | * the underlying device */ | |
e4a3507e | 667 | rv = readfunc(block, 0, |
3e308f20 DB |
668 | (uint8_t *)&luks->header, |
669 | sizeof(luks->header), | |
e4a3507e | 670 | opaque, |
37509233 | 671 | errp); |
3e308f20 DB |
672 | if (rv < 0) { |
673 | ret = rv; | |
674 | goto fail; | |
675 | } | |
676 | ||
677 | /* The header is always stored in big-endian format, so | |
678 | * convert everything to native */ | |
679 | be16_to_cpus(&luks->header.version); | |
680 | be32_to_cpus(&luks->header.payload_offset); | |
681 | be32_to_cpus(&luks->header.key_bytes); | |
682 | be32_to_cpus(&luks->header.master_key_iterations); | |
683 | ||
684 | for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { | |
685 | be32_to_cpus(&luks->header.key_slots[i].active); | |
686 | be32_to_cpus(&luks->header.key_slots[i].iterations); | |
687 | be32_to_cpus(&luks->header.key_slots[i].key_offset); | |
688 | be32_to_cpus(&luks->header.key_slots[i].stripes); | |
689 | } | |
690 | ||
691 | if (memcmp(luks->header.magic, qcrypto_block_luks_magic, | |
692 | QCRYPTO_BLOCK_LUKS_MAGIC_LEN) != 0) { | |
693 | error_setg(errp, "Volume is not in LUKS format"); | |
694 | ret = -EINVAL; | |
695 | goto fail; | |
696 | } | |
697 | if (luks->header.version != QCRYPTO_BLOCK_LUKS_VERSION) { | |
698 | error_setg(errp, "LUKS version %" PRIu32 " is not supported", | |
699 | luks->header.version); | |
700 | ret = -ENOTSUP; | |
701 | goto fail; | |
702 | } | |
703 | ||
704 | /* | |
705 | * The cipher_mode header contains a string that we have | |
706 | * to further parse, of the format | |
707 | * | |
708 | * <cipher-mode>-<iv-generator>[:<iv-hash>] | |
709 | * | |
710 | * eg cbc-essiv:sha256, cbc-plain64 | |
711 | */ | |
712 | ivgen_name = strchr(luks->header.cipher_mode, '-'); | |
713 | if (!ivgen_name) { | |
714 | ret = -EINVAL; | |
715 | error_setg(errp, "Unexpected cipher mode string format %s", | |
716 | luks->header.cipher_mode); | |
717 | goto fail; | |
718 | } | |
719 | *ivgen_name = '\0'; | |
720 | ivgen_name++; | |
721 | ||
722 | ivhash_name = strchr(ivgen_name, ':'); | |
723 | if (!ivhash_name) { | |
724 | ivhash = 0; | |
725 | } else { | |
726 | *ivhash_name = '\0'; | |
727 | ivhash_name++; | |
728 | ||
729 | ivhash = qcrypto_block_luks_hash_name_lookup(ivhash_name, | |
730 | &local_err); | |
731 | if (local_err) { | |
732 | ret = -ENOTSUP; | |
733 | error_propagate(errp, local_err); | |
734 | goto fail; | |
735 | } | |
736 | } | |
737 | ||
738 | ciphermode = qcrypto_block_luks_cipher_mode_lookup(luks->header.cipher_mode, | |
739 | &local_err); | |
740 | if (local_err) { | |
741 | ret = -ENOTSUP; | |
742 | error_propagate(errp, local_err); | |
743 | goto fail; | |
744 | } | |
745 | ||
746 | cipheralg = qcrypto_block_luks_cipher_name_lookup(luks->header.cipher_name, | |
747 | ciphermode, | |
748 | luks->header.key_bytes, | |
749 | &local_err); | |
750 | if (local_err) { | |
751 | ret = -ENOTSUP; | |
752 | error_propagate(errp, local_err); | |
753 | goto fail; | |
754 | } | |
755 | ||
756 | hash = qcrypto_block_luks_hash_name_lookup(luks->header.hash_spec, | |
757 | &local_err); | |
758 | if (local_err) { | |
759 | ret = -ENOTSUP; | |
760 | error_propagate(errp, local_err); | |
761 | goto fail; | |
762 | } | |
763 | ||
764 | ivalg = qcrypto_block_luks_ivgen_name_lookup(ivgen_name, | |
765 | &local_err); | |
766 | if (local_err) { | |
767 | ret = -ENOTSUP; | |
768 | error_propagate(errp, local_err); | |
769 | goto fail; | |
770 | } | |
771 | ||
772 | if (ivalg == QCRYPTO_IVGEN_ALG_ESSIV) { | |
8b7cdba3 DB |
773 | if (!ivhash_name) { |
774 | ret = -EINVAL; | |
775 | error_setg(errp, "Missing IV generator hash specification"); | |
776 | goto fail; | |
777 | } | |
3e308f20 DB |
778 | ivcipheralg = qcrypto_block_luks_essiv_cipher(cipheralg, |
779 | ivhash, | |
780 | &local_err); | |
781 | if (local_err) { | |
782 | ret = -ENOTSUP; | |
783 | error_propagate(errp, local_err); | |
784 | goto fail; | |
785 | } | |
786 | } else { | |
8b7cdba3 DB |
787 | /* Note we parsed the ivhash_name earlier in the cipher_mode |
788 | * spec string even with plain/plain64 ivgens, but we | |
789 | * will ignore it, since it is irrelevant for these ivgens. | |
790 | * This is for compat with dm-crypt which will silently | |
791 | * ignore hash names with these ivgens rather than report | |
792 | * an error about the invalid usage | |
793 | */ | |
3e308f20 DB |
794 | ivcipheralg = cipheralg; |
795 | } | |
796 | ||
797 | if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) { | |
798 | /* Try to find which key slot our password is valid for | |
799 | * and unlock the master key from that slot. | |
800 | */ | |
801 | if (qcrypto_block_luks_find_key(block, | |
802 | password, | |
803 | cipheralg, ciphermode, | |
804 | hash, | |
805 | ivalg, | |
806 | ivcipheralg, | |
807 | ivhash, | |
808 | &masterkey, &masterkeylen, | |
809 | readfunc, opaque, | |
810 | errp) < 0) { | |
811 | ret = -EACCES; | |
812 | goto fail; | |
813 | } | |
814 | ||
815 | /* We have a valid master key now, so can setup the | |
816 | * block device payload decryption objects | |
817 | */ | |
818 | block->kdfhash = hash; | |
819 | block->niv = qcrypto_cipher_get_iv_len(cipheralg, | |
820 | ciphermode); | |
821 | block->ivgen = qcrypto_ivgen_new(ivalg, | |
822 | ivcipheralg, | |
823 | ivhash, | |
824 | masterkey, masterkeylen, | |
825 | errp); | |
826 | if (!block->ivgen) { | |
827 | ret = -ENOTSUP; | |
828 | goto fail; | |
829 | } | |
830 | ||
c972fa12 VSO |
831 | ret = qcrypto_block_init_cipher(block, cipheralg, ciphermode, |
832 | masterkey, masterkeylen, n_threads, | |
833 | errp); | |
834 | if (ret < 0) { | |
3e308f20 DB |
835 | ret = -ENOTSUP; |
836 | goto fail; | |
837 | } | |
838 | } | |
839 | ||
850f49de | 840 | block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE; |
3e308f20 | 841 | block->payload_offset = luks->header.payload_offset * |
850f49de | 842 | block->sector_size; |
3e308f20 | 843 | |
40c85028 DB |
844 | luks->cipher_alg = cipheralg; |
845 | luks->cipher_mode = ciphermode; | |
846 | luks->ivgen_alg = ivalg; | |
847 | luks->ivgen_hash_alg = ivhash; | |
848 | luks->hash_alg = hash; | |
849 | ||
3e308f20 DB |
850 | return 0; |
851 | ||
852 | fail: | |
c972fa12 | 853 | qcrypto_block_free_cipher(block); |
3e308f20 DB |
854 | qcrypto_ivgen_free(block->ivgen); |
855 | g_free(luks); | |
3e308f20 DB |
856 | return ret; |
857 | } | |
858 | ||
859 | ||
2ef950f9 FZ |
860 | static void |
861 | qcrypto_block_luks_uuid_gen(uint8_t *uuidstr) | |
3e308f20 | 862 | { |
2ef950f9 FZ |
863 | QemuUUID uuid; |
864 | qemu_uuid_generate(&uuid); | |
865 | qemu_uuid_unparse(&uuid, (char *)uuidstr); | |
3e308f20 DB |
866 | } |
867 | ||
868 | static int | |
869 | qcrypto_block_luks_create(QCryptoBlock *block, | |
870 | QCryptoBlockCreateOptions *options, | |
1cd9a787 | 871 | const char *optprefix, |
3e308f20 DB |
872 | QCryptoBlockInitFunc initfunc, |
873 | QCryptoBlockWriteFunc writefunc, | |
874 | void *opaque, | |
875 | Error **errp) | |
876 | { | |
877 | QCryptoBlockLUKS *luks; | |
878 | QCryptoBlockCreateOptionsLUKS luks_opts; | |
879 | Error *local_err = NULL; | |
57b9f113 DB |
880 | g_autofree uint8_t *masterkey = NULL; |
881 | g_autofree uint8_t *slotkey = NULL; | |
882 | g_autofree uint8_t *splitkey = NULL; | |
3e308f20 DB |
883 | size_t splitkeylen = 0; |
884 | size_t i; | |
57b9f113 DB |
885 | g_autoptr(QCryptoCipher) cipher = NULL; |
886 | g_autoptr(QCryptoIVGen) ivgen = NULL; | |
887 | g_autofree char *password = NULL; | |
3e308f20 DB |
888 | const char *cipher_alg; |
889 | const char *cipher_mode; | |
890 | const char *ivgen_alg; | |
891 | const char *ivgen_hash_alg = NULL; | |
892 | const char *hash_alg; | |
57b9f113 | 893 | g_autofree char *cipher_mode_spec = NULL; |
3e308f20 | 894 | QCryptoCipherAlgorithm ivcipheralg = 0; |
59b060be | 895 | uint64_t iters; |
3e308f20 DB |
896 | |
897 | memcpy(&luks_opts, &options->u.luks, sizeof(luks_opts)); | |
3bd18890 | 898 | if (!luks_opts.has_iter_time) { |
2ab66cd5 | 899 | luks_opts.iter_time = 2000; |
3bd18890 | 900 | } |
3e308f20 DB |
901 | if (!luks_opts.has_cipher_alg) { |
902 | luks_opts.cipher_alg = QCRYPTO_CIPHER_ALG_AES_256; | |
903 | } | |
904 | if (!luks_opts.has_cipher_mode) { | |
905 | luks_opts.cipher_mode = QCRYPTO_CIPHER_MODE_XTS; | |
906 | } | |
907 | if (!luks_opts.has_ivgen_alg) { | |
908 | luks_opts.ivgen_alg = QCRYPTO_IVGEN_ALG_PLAIN64; | |
909 | } | |
910 | if (!luks_opts.has_hash_alg) { | |
911 | luks_opts.hash_alg = QCRYPTO_HASH_ALG_SHA256; | |
912 | } | |
8b7cdba3 DB |
913 | if (luks_opts.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) { |
914 | if (!luks_opts.has_ivgen_hash_alg) { | |
915 | luks_opts.ivgen_hash_alg = QCRYPTO_HASH_ALG_SHA256; | |
916 | luks_opts.has_ivgen_hash_alg = true; | |
917 | } | |
918 | } | |
919 | /* Note we're allowing ivgen_hash_alg to be set even for | |
920 | * non-essiv iv generators that don't need a hash. It will | |
921 | * be silently ignored, for compatibility with dm-crypt */ | |
3e308f20 DB |
922 | |
923 | if (!options->u.luks.key_secret) { | |
1cd9a787 DB |
924 | error_setg(errp, "Parameter '%skey-secret' is required for cipher", |
925 | optprefix ? optprefix : ""); | |
3e308f20 DB |
926 | return -1; |
927 | } | |
928 | password = qcrypto_secret_lookup_as_utf8(luks_opts.key_secret, errp); | |
929 | if (!password) { | |
930 | return -1; | |
931 | } | |
932 | ||
933 | luks = g_new0(QCryptoBlockLUKS, 1); | |
934 | block->opaque = luks; | |
935 | ||
936 | memcpy(luks->header.magic, qcrypto_block_luks_magic, | |
937 | QCRYPTO_BLOCK_LUKS_MAGIC_LEN); | |
938 | ||
939 | /* We populate the header in native endianness initially and | |
940 | * then convert everything to big endian just before writing | |
941 | * it out to disk | |
942 | */ | |
943 | luks->header.version = QCRYPTO_BLOCK_LUKS_VERSION; | |
2ef950f9 | 944 | qcrypto_block_luks_uuid_gen(luks->header.uuid); |
3e308f20 DB |
945 | |
946 | cipher_alg = qcrypto_block_luks_cipher_alg_lookup(luks_opts.cipher_alg, | |
947 | errp); | |
948 | if (!cipher_alg) { | |
949 | goto error; | |
950 | } | |
951 | ||
977c736f MA |
952 | cipher_mode = QCryptoCipherMode_str(luks_opts.cipher_mode); |
953 | ivgen_alg = QCryptoIVGenAlgorithm_str(luks_opts.ivgen_alg); | |
3e308f20 | 954 | if (luks_opts.has_ivgen_hash_alg) { |
977c736f | 955 | ivgen_hash_alg = QCryptoHashAlgorithm_str(luks_opts.ivgen_hash_alg); |
3e308f20 DB |
956 | cipher_mode_spec = g_strdup_printf("%s-%s:%s", cipher_mode, ivgen_alg, |
957 | ivgen_hash_alg); | |
958 | } else { | |
959 | cipher_mode_spec = g_strdup_printf("%s-%s", cipher_mode, ivgen_alg); | |
960 | } | |
977c736f | 961 | hash_alg = QCryptoHashAlgorithm_str(luks_opts.hash_alg); |
3e308f20 DB |
962 | |
963 | ||
964 | if (strlen(cipher_alg) >= QCRYPTO_BLOCK_LUKS_CIPHER_NAME_LEN) { | |
965 | error_setg(errp, "Cipher name '%s' is too long for LUKS header", | |
966 | cipher_alg); | |
967 | goto error; | |
968 | } | |
969 | if (strlen(cipher_mode_spec) >= QCRYPTO_BLOCK_LUKS_CIPHER_MODE_LEN) { | |
970 | error_setg(errp, "Cipher mode '%s' is too long for LUKS header", | |
971 | cipher_mode_spec); | |
972 | goto error; | |
973 | } | |
974 | if (strlen(hash_alg) >= QCRYPTO_BLOCK_LUKS_HASH_SPEC_LEN) { | |
975 | error_setg(errp, "Hash name '%s' is too long for LUKS header", | |
976 | hash_alg); | |
977 | goto error; | |
978 | } | |
979 | ||
980 | if (luks_opts.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) { | |
981 | ivcipheralg = qcrypto_block_luks_essiv_cipher(luks_opts.cipher_alg, | |
982 | luks_opts.ivgen_hash_alg, | |
983 | &local_err); | |
984 | if (local_err) { | |
985 | error_propagate(errp, local_err); | |
986 | goto error; | |
987 | } | |
988 | } else { | |
989 | ivcipheralg = luks_opts.cipher_alg; | |
990 | } | |
991 | ||
992 | strcpy(luks->header.cipher_name, cipher_alg); | |
993 | strcpy(luks->header.cipher_mode, cipher_mode_spec); | |
994 | strcpy(luks->header.hash_spec, hash_alg); | |
995 | ||
996 | luks->header.key_bytes = qcrypto_cipher_get_key_len(luks_opts.cipher_alg); | |
997 | if (luks_opts.cipher_mode == QCRYPTO_CIPHER_MODE_XTS) { | |
998 | luks->header.key_bytes *= 2; | |
999 | } | |
1000 | ||
1001 | /* Generate the salt used for hashing the master key | |
1002 | * with PBKDF later | |
1003 | */ | |
1004 | if (qcrypto_random_bytes(luks->header.master_key_salt, | |
1005 | QCRYPTO_BLOCK_LUKS_SALT_LEN, | |
1006 | errp) < 0) { | |
1007 | goto error; | |
1008 | } | |
1009 | ||
1010 | /* Generate random master key */ | |
1011 | masterkey = g_new0(uint8_t, luks->header.key_bytes); | |
1012 | if (qcrypto_random_bytes(masterkey, | |
1013 | luks->header.key_bytes, errp) < 0) { | |
1014 | goto error; | |
1015 | } | |
1016 | ||
1017 | ||
1018 | /* Setup the block device payload encryption objects */ | |
c972fa12 VSO |
1019 | if (qcrypto_block_init_cipher(block, luks_opts.cipher_alg, |
1020 | luks_opts.cipher_mode, masterkey, | |
1021 | luks->header.key_bytes, 1, errp) < 0) { | |
3e308f20 DB |
1022 | goto error; |
1023 | } | |
1024 | ||
1025 | block->kdfhash = luks_opts.hash_alg; | |
1026 | block->niv = qcrypto_cipher_get_iv_len(luks_opts.cipher_alg, | |
1027 | luks_opts.cipher_mode); | |
1028 | block->ivgen = qcrypto_ivgen_new(luks_opts.ivgen_alg, | |
1029 | ivcipheralg, | |
1030 | luks_opts.ivgen_hash_alg, | |
1031 | masterkey, luks->header.key_bytes, | |
1032 | errp); | |
1033 | ||
1034 | if (!block->ivgen) { | |
1035 | goto error; | |
1036 | } | |
1037 | ||
1038 | ||
1039 | /* Determine how many iterations we need to hash the master | |
1040 | * key, in order to have 1 second of compute time used | |
1041 | */ | |
59b060be DB |
1042 | iters = qcrypto_pbkdf2_count_iters(luks_opts.hash_alg, |
1043 | masterkey, luks->header.key_bytes, | |
1044 | luks->header.master_key_salt, | |
1045 | QCRYPTO_BLOCK_LUKS_SALT_LEN, | |
e74aabcf | 1046 | QCRYPTO_BLOCK_LUKS_DIGEST_LEN, |
59b060be | 1047 | &local_err); |
3e308f20 DB |
1048 | if (local_err) { |
1049 | error_propagate(errp, local_err); | |
1050 | goto error; | |
1051 | } | |
1052 | ||
3bd18890 DB |
1053 | if (iters > (ULLONG_MAX / luks_opts.iter_time)) { |
1054 | error_setg_errno(errp, ERANGE, | |
1055 | "PBKDF iterations %llu too large to scale", | |
1056 | (unsigned long long)iters); | |
1057 | goto error; | |
1058 | } | |
1059 | ||
1060 | /* iter_time was in millis, but count_iters reported for secs */ | |
1061 | iters = iters * luks_opts.iter_time / 1000; | |
1062 | ||
3e308f20 DB |
1063 | /* Why /= 8 ? That matches cryptsetup, but there's no |
1064 | * explanation why they chose /= 8... Probably so that | |
1065 | * if all 8 keyslots are active we only spend 1 second | |
1066 | * in total time to check all keys */ | |
59b060be DB |
1067 | iters /= 8; |
1068 | if (iters > UINT32_MAX) { | |
1069 | error_setg_errno(errp, ERANGE, | |
1070 | "PBKDF iterations %llu larger than %u", | |
1071 | (unsigned long long)iters, UINT32_MAX); | |
1072 | goto error; | |
1073 | } | |
1074 | iters = MAX(iters, QCRYPTO_BLOCK_LUKS_MIN_MASTER_KEY_ITERS); | |
1075 | luks->header.master_key_iterations = iters; | |
3e308f20 DB |
1076 | |
1077 | /* Hash the master key, saving the result in the LUKS | |
1078 | * header. This hash is used when opening the encrypted | |
1079 | * device to verify that the user password unlocked a | |
1080 | * valid master key | |
1081 | */ | |
1082 | if (qcrypto_pbkdf2(luks_opts.hash_alg, | |
1083 | masterkey, luks->header.key_bytes, | |
1084 | luks->header.master_key_salt, | |
1085 | QCRYPTO_BLOCK_LUKS_SALT_LEN, | |
1086 | luks->header.master_key_iterations, | |
1087 | luks->header.master_key_digest, | |
1088 | QCRYPTO_BLOCK_LUKS_DIGEST_LEN, | |
1089 | errp) < 0) { | |
1090 | goto error; | |
1091 | } | |
1092 | ||
1093 | ||
1094 | /* Although LUKS has multiple key slots, we're just going | |
1095 | * to use the first key slot */ | |
1096 | splitkeylen = luks->header.key_bytes * QCRYPTO_BLOCK_LUKS_STRIPES; | |
1097 | for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { | |
1098 | luks->header.key_slots[i].active = i == 0 ? | |
1099 | QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED : | |
1100 | QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED; | |
1101 | luks->header.key_slots[i].stripes = QCRYPTO_BLOCK_LUKS_STRIPES; | |
1102 | ||
1103 | /* This calculation doesn't match that shown in the spec, | |
1104 | * but instead follows the cryptsetup implementation. | |
1105 | */ | |
1106 | luks->header.key_slots[i].key_offset = | |
1107 | (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET / | |
1108 | QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) + | |
207ba7c8 | 1109 | (ROUND_UP(DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE), |
3e308f20 DB |
1110 | (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET / |
1111 | QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) * i); | |
1112 | } | |
1113 | ||
1114 | if (qcrypto_random_bytes(luks->header.key_slots[0].salt, | |
1115 | QCRYPTO_BLOCK_LUKS_SALT_LEN, | |
1116 | errp) < 0) { | |
1117 | goto error; | |
1118 | } | |
1119 | ||
1120 | /* Again we determine how many iterations are required to | |
1121 | * hash the user password while consuming 1 second of compute | |
1122 | * time */ | |
59b060be DB |
1123 | iters = qcrypto_pbkdf2_count_iters(luks_opts.hash_alg, |
1124 | (uint8_t *)password, strlen(password), | |
1125 | luks->header.key_slots[0].salt, | |
1126 | QCRYPTO_BLOCK_LUKS_SALT_LEN, | |
e74aabcf | 1127 | luks->header.key_bytes, |
59b060be | 1128 | &local_err); |
3e308f20 DB |
1129 | if (local_err) { |
1130 | error_propagate(errp, local_err); | |
1131 | goto error; | |
1132 | } | |
3bd18890 DB |
1133 | |
1134 | if (iters > (ULLONG_MAX / luks_opts.iter_time)) { | |
1135 | error_setg_errno(errp, ERANGE, | |
1136 | "PBKDF iterations %llu too large to scale", | |
1137 | (unsigned long long)iters); | |
1138 | goto error; | |
1139 | } | |
1140 | ||
1141 | /* iter_time was in millis, but count_iters reported for secs */ | |
1142 | iters = iters * luks_opts.iter_time / 1000; | |
1143 | ||
59b060be DB |
1144 | if (iters > UINT32_MAX) { |
1145 | error_setg_errno(errp, ERANGE, | |
1146 | "PBKDF iterations %llu larger than %u", | |
1147 | (unsigned long long)iters, UINT32_MAX); | |
1148 | goto error; | |
1149 | } | |
1150 | ||
1151 | luks->header.key_slots[0].iterations = | |
1152 | MAX(iters, QCRYPTO_BLOCK_LUKS_MIN_SLOT_KEY_ITERS); | |
3e308f20 DB |
1153 | |
1154 | ||
1155 | /* Generate a key that we'll use to encrypt the master | |
1156 | * key, from the user's password | |
1157 | */ | |
1158 | slotkey = g_new0(uint8_t, luks->header.key_bytes); | |
1159 | if (qcrypto_pbkdf2(luks_opts.hash_alg, | |
1160 | (uint8_t *)password, strlen(password), | |
1161 | luks->header.key_slots[0].salt, | |
1162 | QCRYPTO_BLOCK_LUKS_SALT_LEN, | |
1163 | luks->header.key_slots[0].iterations, | |
1164 | slotkey, luks->header.key_bytes, | |
1165 | errp) < 0) { | |
1166 | goto error; | |
1167 | } | |
1168 | ||
1169 | ||
1170 | /* Setup the encryption objects needed to encrypt the | |
1171 | * master key material | |
1172 | */ | |
1173 | cipher = qcrypto_cipher_new(luks_opts.cipher_alg, | |
1174 | luks_opts.cipher_mode, | |
1175 | slotkey, luks->header.key_bytes, | |
1176 | errp); | |
1177 | if (!cipher) { | |
1178 | goto error; | |
1179 | } | |
1180 | ||
1181 | ivgen = qcrypto_ivgen_new(luks_opts.ivgen_alg, | |
1182 | ivcipheralg, | |
1183 | luks_opts.ivgen_hash_alg, | |
1184 | slotkey, luks->header.key_bytes, | |
1185 | errp); | |
1186 | if (!ivgen) { | |
1187 | goto error; | |
1188 | } | |
1189 | ||
1190 | /* Before storing the master key, we need to vastly | |
1191 | * increase its size, as protection against forensic | |
1192 | * disk data recovery */ | |
1193 | splitkey = g_new0(uint8_t, splitkeylen); | |
1194 | ||
1195 | if (qcrypto_afsplit_encode(luks_opts.hash_alg, | |
1196 | luks->header.key_bytes, | |
1197 | luks->header.key_slots[0].stripes, | |
1198 | masterkey, | |
1199 | splitkey, | |
1200 | errp) < 0) { | |
1201 | goto error; | |
1202 | } | |
1203 | ||
1204 | /* Now we encrypt the split master key with the key generated | |
1205 | * from the user's password, before storing it */ | |
0270417c VSO |
1206 | if (qcrypto_block_cipher_encrypt_helper(cipher, block->niv, ivgen, |
1207 | QCRYPTO_BLOCK_LUKS_SECTOR_SIZE, | |
1208 | 0, | |
1209 | splitkey, | |
1210 | splitkeylen, | |
1211 | errp) < 0) { | |
3e308f20 DB |
1212 | goto error; |
1213 | } | |
1214 | ||
1215 | ||
1216 | /* The total size of the LUKS headers is the partition header + key | |
1217 | * slot headers, rounded up to the nearest sector, combined with | |
1218 | * the size of each master key material region, also rounded up | |
1219 | * to the nearest sector */ | |
1220 | luks->header.payload_offset = | |
1221 | (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET / | |
1222 | QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) + | |
207ba7c8 | 1223 | (ROUND_UP(DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE), |
3e308f20 DB |
1224 | (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET / |
1225 | QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) * | |
1226 | QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS); | |
1227 | ||
850f49de | 1228 | block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE; |
3e308f20 | 1229 | block->payload_offset = luks->header.payload_offset * |
850f49de | 1230 | block->sector_size; |
3e308f20 DB |
1231 | |
1232 | /* Reserve header space to match payload offset */ | |
e4a3507e | 1233 | initfunc(block, block->payload_offset, opaque, &local_err); |
3e308f20 DB |
1234 | if (local_err) { |
1235 | error_propagate(errp, local_err); | |
1236 | goto error; | |
1237 | } | |
1238 | ||
1239 | /* Everything on disk uses Big Endian, so flip header fields | |
1240 | * before writing them */ | |
1241 | cpu_to_be16s(&luks->header.version); | |
1242 | cpu_to_be32s(&luks->header.payload_offset); | |
1243 | cpu_to_be32s(&luks->header.key_bytes); | |
1244 | cpu_to_be32s(&luks->header.master_key_iterations); | |
1245 | ||
1246 | for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { | |
1247 | cpu_to_be32s(&luks->header.key_slots[i].active); | |
1248 | cpu_to_be32s(&luks->header.key_slots[i].iterations); | |
1249 | cpu_to_be32s(&luks->header.key_slots[i].key_offset); | |
1250 | cpu_to_be32s(&luks->header.key_slots[i].stripes); | |
1251 | } | |
1252 | ||
1253 | ||
1254 | /* Write out the partition header and key slot headers */ | |
e4a3507e | 1255 | writefunc(block, 0, |
3e308f20 DB |
1256 | (const uint8_t *)&luks->header, |
1257 | sizeof(luks->header), | |
e4a3507e | 1258 | opaque, |
37509233 | 1259 | &local_err); |
3e308f20 DB |
1260 | |
1261 | /* Delay checking local_err until we've byte-swapped */ | |
1262 | ||
1263 | /* Byte swap the header back to native, in case we need | |
1264 | * to read it again later */ | |
1265 | be16_to_cpus(&luks->header.version); | |
1266 | be32_to_cpus(&luks->header.payload_offset); | |
1267 | be32_to_cpus(&luks->header.key_bytes); | |
1268 | be32_to_cpus(&luks->header.master_key_iterations); | |
1269 | ||
1270 | for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { | |
1271 | be32_to_cpus(&luks->header.key_slots[i].active); | |
1272 | be32_to_cpus(&luks->header.key_slots[i].iterations); | |
1273 | be32_to_cpus(&luks->header.key_slots[i].key_offset); | |
1274 | be32_to_cpus(&luks->header.key_slots[i].stripes); | |
1275 | } | |
1276 | ||
1277 | if (local_err) { | |
1278 | error_propagate(errp, local_err); | |
1279 | goto error; | |
1280 | } | |
1281 | ||
1282 | /* Write out the master key material, starting at the | |
1283 | * sector immediately following the partition header. */ | |
e4a3507e | 1284 | if (writefunc(block, |
3e308f20 DB |
1285 | luks->header.key_slots[0].key_offset * |
1286 | QCRYPTO_BLOCK_LUKS_SECTOR_SIZE, | |
1287 | splitkey, splitkeylen, | |
e4a3507e | 1288 | opaque, |
37509233 | 1289 | errp) != splitkeylen) { |
3e308f20 DB |
1290 | goto error; |
1291 | } | |
1292 | ||
40c85028 DB |
1293 | luks->cipher_alg = luks_opts.cipher_alg; |
1294 | luks->cipher_mode = luks_opts.cipher_mode; | |
1295 | luks->ivgen_alg = luks_opts.ivgen_alg; | |
1296 | luks->ivgen_hash_alg = luks_opts.ivgen_hash_alg; | |
1297 | luks->hash_alg = luks_opts.hash_alg; | |
1298 | ||
3e308f20 | 1299 | memset(masterkey, 0, luks->header.key_bytes); |
3e308f20 | 1300 | memset(slotkey, 0, luks->header.key_bytes); |
3e308f20 DB |
1301 | |
1302 | return 0; | |
1303 | ||
1304 | error: | |
1305 | if (masterkey) { | |
1306 | memset(masterkey, 0, luks->header.key_bytes); | |
1307 | } | |
3e308f20 DB |
1308 | if (slotkey) { |
1309 | memset(slotkey, 0, luks->header.key_bytes); | |
1310 | } | |
3e308f20 | 1311 | |
c972fa12 | 1312 | qcrypto_block_free_cipher(block); |
b640adca VSO |
1313 | qcrypto_ivgen_free(block->ivgen); |
1314 | ||
3e308f20 DB |
1315 | g_free(luks); |
1316 | return -1; | |
1317 | } | |
1318 | ||
1319 | ||
40c85028 DB |
1320 | static int qcrypto_block_luks_get_info(QCryptoBlock *block, |
1321 | QCryptoBlockInfo *info, | |
1322 | Error **errp) | |
1323 | { | |
1324 | QCryptoBlockLUKS *luks = block->opaque; | |
1325 | QCryptoBlockInfoLUKSSlot *slot; | |
1326 | QCryptoBlockInfoLUKSSlotList *slots = NULL, **prev = &info->u.luks.slots; | |
1327 | size_t i; | |
1328 | ||
1329 | info->u.luks.cipher_alg = luks->cipher_alg; | |
1330 | info->u.luks.cipher_mode = luks->cipher_mode; | |
1331 | info->u.luks.ivgen_alg = luks->ivgen_alg; | |
1332 | if (info->u.luks.ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) { | |
1333 | info->u.luks.has_ivgen_hash_alg = true; | |
1334 | info->u.luks.ivgen_hash_alg = luks->ivgen_hash_alg; | |
1335 | } | |
1336 | info->u.luks.hash_alg = luks->hash_alg; | |
1337 | info->u.luks.payload_offset = block->payload_offset; | |
1338 | info->u.luks.master_key_iters = luks->header.master_key_iterations; | |
1339 | info->u.luks.uuid = g_strndup((const char *)luks->header.uuid, | |
1340 | sizeof(luks->header.uuid)); | |
1341 | ||
1342 | for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { | |
1343 | slots = g_new0(QCryptoBlockInfoLUKSSlotList, 1); | |
1344 | *prev = slots; | |
1345 | ||
1346 | slots->value = slot = g_new0(QCryptoBlockInfoLUKSSlot, 1); | |
1347 | slot->active = luks->header.key_slots[i].active == | |
1348 | QCRYPTO_BLOCK_LUKS_KEY_SLOT_ENABLED; | |
1349 | slot->key_offset = luks->header.key_slots[i].key_offset | |
1350 | * QCRYPTO_BLOCK_LUKS_SECTOR_SIZE; | |
1351 | if (slot->active) { | |
1352 | slot->has_iters = true; | |
1353 | slot->iters = luks->header.key_slots[i].iterations; | |
1354 | slot->has_stripes = true; | |
1355 | slot->stripes = luks->header.key_slots[i].stripes; | |
1356 | } | |
1357 | ||
1358 | prev = &slots->next; | |
1359 | } | |
1360 | ||
1361 | return 0; | |
1362 | } | |
1363 | ||
1364 | ||
3e308f20 DB |
1365 | static void qcrypto_block_luks_cleanup(QCryptoBlock *block) |
1366 | { | |
1367 | g_free(block->opaque); | |
1368 | } | |
1369 | ||
1370 | ||
1371 | static int | |
1372 | qcrypto_block_luks_decrypt(QCryptoBlock *block, | |
4609742a | 1373 | uint64_t offset, |
3e308f20 DB |
1374 | uint8_t *buf, |
1375 | size_t len, | |
1376 | Error **errp) | |
1377 | { | |
4609742a DB |
1378 | assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)); |
1379 | assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)); | |
0f0d596c VSO |
1380 | return qcrypto_block_decrypt_helper(block, |
1381 | QCRYPTO_BLOCK_LUKS_SECTOR_SIZE, | |
1382 | offset, buf, len, errp); | |
3e308f20 DB |
1383 | } |
1384 | ||
1385 | ||
1386 | static int | |
1387 | qcrypto_block_luks_encrypt(QCryptoBlock *block, | |
4609742a | 1388 | uint64_t offset, |
3e308f20 DB |
1389 | uint8_t *buf, |
1390 | size_t len, | |
1391 | Error **errp) | |
1392 | { | |
4609742a DB |
1393 | assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)); |
1394 | assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)); | |
0f0d596c VSO |
1395 | return qcrypto_block_encrypt_helper(block, |
1396 | QCRYPTO_BLOCK_LUKS_SECTOR_SIZE, | |
1397 | offset, buf, len, errp); | |
3e308f20 DB |
1398 | } |
1399 | ||
1400 | ||
1401 | const QCryptoBlockDriver qcrypto_block_driver_luks = { | |
1402 | .open = qcrypto_block_luks_open, | |
1403 | .create = qcrypto_block_luks_create, | |
40c85028 | 1404 | .get_info = qcrypto_block_luks_get_info, |
3e308f20 DB |
1405 | .cleanup = qcrypto_block_luks_cleanup, |
1406 | .decrypt = qcrypto_block_luks_decrypt, | |
1407 | .encrypt = qcrypto_block_luks_encrypt, | |
1408 | .has_format = qcrypto_block_luks_has_format, | |
1409 | }; |