Commit | Line | Data |
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a4ffc152 MP |
1 | /* |
2 | * Copyright (C) 2012 Red Hat, Inc. | |
3 | * | |
4 | * Author: Mikulas Patocka <mpatocka@redhat.com> | |
5 | * | |
6 | * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors | |
7 | * | |
8 | * This file is released under the GPLv2. | |
9 | * | |
10 | * In the file "/sys/module/dm_verity/parameters/prefetch_cluster" you can set | |
11 | * default prefetch value. Data are read in "prefetch_cluster" chunks from the | |
12 | * hash device. Setting this greatly improves performance when data and hash | |
13 | * are on the same disk on different partitions on devices with poor random | |
14 | * access behavior. | |
15 | */ | |
16 | ||
ffa39380 | 17 | #include "dm-verity.h" |
a739ff3f | 18 | #include "dm-verity-fec.h" |
a4ffc152 MP |
19 | |
20 | #include <linux/module.h> | |
65ff5b7d | 21 | #include <linux/reboot.h> |
a4ffc152 MP |
22 | |
23 | #define DM_MSG_PREFIX "verity" | |
24 | ||
65ff5b7d ST |
25 | #define DM_VERITY_ENV_LENGTH 42 |
26 | #define DM_VERITY_ENV_VAR_NAME "DM_VERITY_ERR_BLOCK_NR" | |
27 | ||
a4ffc152 MP |
28 | #define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144 |
29 | ||
65ff5b7d ST |
30 | #define DM_VERITY_MAX_CORRUPTED_ERRS 100 |
31 | ||
32 | #define DM_VERITY_OPT_LOGGING "ignore_corruption" | |
33 | #define DM_VERITY_OPT_RESTART "restart_on_corruption" | |
0cc37c2d | 34 | #define DM_VERITY_OPT_IGN_ZEROES "ignore_zero_blocks" |
a4ffc152 | 35 | |
0cc37c2d | 36 | #define DM_VERITY_OPTS_MAX (2 + DM_VERITY_OPTS_FEC) |
753c1fd0 | 37 | |
a4ffc152 MP |
38 | static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE; |
39 | ||
40 | module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR); | |
41 | ||
3b6b7813 MP |
42 | struct dm_verity_prefetch_work { |
43 | struct work_struct work; | |
44 | struct dm_verity *v; | |
45 | sector_t block; | |
46 | unsigned n_blocks; | |
47 | }; | |
48 | ||
a4ffc152 MP |
49 | /* |
50 | * Auxiliary structure appended to each dm-bufio buffer. If the value | |
51 | * hash_verified is nonzero, hash of the block has been verified. | |
52 | * | |
53 | * The variable hash_verified is set to 0 when allocating the buffer, then | |
54 | * it can be changed to 1 and it is never reset to 0 again. | |
55 | * | |
56 | * There is no lock around this value, a race condition can at worst cause | |
57 | * that multiple processes verify the hash of the same buffer simultaneously | |
58 | * and write 1 to hash_verified simultaneously. | |
59 | * This condition is harmless, so we don't need locking. | |
60 | */ | |
61 | struct buffer_aux { | |
62 | int hash_verified; | |
63 | }; | |
64 | ||
65 | /* | |
66 | * Initialize struct buffer_aux for a freshly created buffer. | |
67 | */ | |
68 | static void dm_bufio_alloc_callback(struct dm_buffer *buf) | |
69 | { | |
70 | struct buffer_aux *aux = dm_bufio_get_aux_data(buf); | |
71 | ||
72 | aux->hash_verified = 0; | |
73 | } | |
74 | ||
75 | /* | |
76 | * Translate input sector number to the sector number on the target device. | |
77 | */ | |
78 | static sector_t verity_map_sector(struct dm_verity *v, sector_t bi_sector) | |
79 | { | |
80 | return v->data_start + dm_target_offset(v->ti, bi_sector); | |
81 | } | |
82 | ||
83 | /* | |
84 | * Return hash position of a specified block at a specified tree level | |
85 | * (0 is the lowest level). | |
86 | * The lowest "hash_per_block_bits"-bits of the result denote hash position | |
87 | * inside a hash block. The remaining bits denote location of the hash block. | |
88 | */ | |
89 | static sector_t verity_position_at_level(struct dm_verity *v, sector_t block, | |
90 | int level) | |
91 | { | |
92 | return block >> (level * v->hash_per_block_bits); | |
93 | } | |
94 | ||
6dbeda34 ST |
95 | /* |
96 | * Wrapper for crypto_shash_init, which handles verity salting. | |
97 | */ | |
98 | static int verity_hash_init(struct dm_verity *v, struct shash_desc *desc) | |
99 | { | |
100 | int r; | |
101 | ||
102 | desc->tfm = v->tfm; | |
103 | desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; | |
104 | ||
105 | r = crypto_shash_init(desc); | |
106 | ||
107 | if (unlikely(r < 0)) { | |
108 | DMERR("crypto_shash_init failed: %d", r); | |
109 | return r; | |
110 | } | |
111 | ||
112 | if (likely(v->version >= 1)) { | |
113 | r = crypto_shash_update(desc, v->salt, v->salt_size); | |
114 | ||
115 | if (unlikely(r < 0)) { | |
116 | DMERR("crypto_shash_update failed: %d", r); | |
117 | return r; | |
118 | } | |
119 | } | |
120 | ||
121 | return 0; | |
122 | } | |
123 | ||
124 | static int verity_hash_update(struct dm_verity *v, struct shash_desc *desc, | |
125 | const u8 *data, size_t len) | |
126 | { | |
127 | int r = crypto_shash_update(desc, data, len); | |
128 | ||
129 | if (unlikely(r < 0)) | |
130 | DMERR("crypto_shash_update failed: %d", r); | |
131 | ||
132 | return r; | |
133 | } | |
134 | ||
135 | static int verity_hash_final(struct dm_verity *v, struct shash_desc *desc, | |
136 | u8 *digest) | |
137 | { | |
138 | int r; | |
139 | ||
140 | if (unlikely(!v->version)) { | |
141 | r = crypto_shash_update(desc, v->salt, v->salt_size); | |
142 | ||
143 | if (r < 0) { | |
144 | DMERR("crypto_shash_update failed: %d", r); | |
145 | return r; | |
146 | } | |
147 | } | |
148 | ||
149 | r = crypto_shash_final(desc, digest); | |
150 | ||
151 | if (unlikely(r < 0)) | |
152 | DMERR("crypto_shash_final failed: %d", r); | |
153 | ||
154 | return r; | |
155 | } | |
156 | ||
ffa39380 ST |
157 | int verity_hash(struct dm_verity *v, struct shash_desc *desc, |
158 | const u8 *data, size_t len, u8 *digest) | |
6dbeda34 ST |
159 | { |
160 | int r; | |
161 | ||
162 | r = verity_hash_init(v, desc); | |
163 | if (unlikely(r < 0)) | |
164 | return r; | |
165 | ||
166 | r = verity_hash_update(v, desc, data, len); | |
167 | if (unlikely(r < 0)) | |
168 | return r; | |
169 | ||
170 | return verity_hash_final(v, desc, digest); | |
171 | } | |
172 | ||
a4ffc152 MP |
173 | static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level, |
174 | sector_t *hash_block, unsigned *offset) | |
175 | { | |
176 | sector_t position = verity_position_at_level(v, block, level); | |
177 | unsigned idx; | |
178 | ||
179 | *hash_block = v->hash_level_block[level] + (position >> v->hash_per_block_bits); | |
180 | ||
181 | if (!offset) | |
182 | return; | |
183 | ||
184 | idx = position & ((1 << v->hash_per_block_bits) - 1); | |
185 | if (!v->version) | |
186 | *offset = idx * v->digest_size; | |
187 | else | |
188 | *offset = idx << (v->hash_dev_block_bits - v->hash_per_block_bits); | |
189 | } | |
190 | ||
65ff5b7d ST |
191 | /* |
192 | * Handle verification errors. | |
193 | */ | |
194 | static int verity_handle_err(struct dm_verity *v, enum verity_block_type type, | |
195 | unsigned long long block) | |
196 | { | |
197 | char verity_env[DM_VERITY_ENV_LENGTH]; | |
198 | char *envp[] = { verity_env, NULL }; | |
199 | const char *type_str = ""; | |
200 | struct mapped_device *md = dm_table_get_md(v->ti->table); | |
201 | ||
202 | /* Corruption should be visible in device status in all modes */ | |
203 | v->hash_failed = 1; | |
204 | ||
205 | if (v->corrupted_errs >= DM_VERITY_MAX_CORRUPTED_ERRS) | |
206 | goto out; | |
207 | ||
208 | v->corrupted_errs++; | |
209 | ||
210 | switch (type) { | |
211 | case DM_VERITY_BLOCK_TYPE_DATA: | |
212 | type_str = "data"; | |
213 | break; | |
214 | case DM_VERITY_BLOCK_TYPE_METADATA: | |
215 | type_str = "metadata"; | |
216 | break; | |
217 | default: | |
218 | BUG(); | |
219 | } | |
220 | ||
221 | DMERR("%s: %s block %llu is corrupted", v->data_dev->name, type_str, | |
222 | block); | |
223 | ||
224 | if (v->corrupted_errs == DM_VERITY_MAX_CORRUPTED_ERRS) | |
225 | DMERR("%s: reached maximum errors", v->data_dev->name); | |
226 | ||
227 | snprintf(verity_env, DM_VERITY_ENV_LENGTH, "%s=%d,%llu", | |
228 | DM_VERITY_ENV_VAR_NAME, type, block); | |
229 | ||
230 | kobject_uevent_env(&disk_to_dev(dm_disk(md))->kobj, KOBJ_CHANGE, envp); | |
231 | ||
232 | out: | |
233 | if (v->mode == DM_VERITY_MODE_LOGGING) | |
234 | return 0; | |
235 | ||
236 | if (v->mode == DM_VERITY_MODE_RESTART) | |
237 | kernel_restart("dm-verity device corrupted"); | |
238 | ||
239 | return 1; | |
240 | } | |
241 | ||
a4ffc152 MP |
242 | /* |
243 | * Verify hash of a metadata block pertaining to the specified data block | |
244 | * ("block" argument) at a specified level ("level" argument). | |
245 | * | |
ffa39380 ST |
246 | * On successful return, verity_io_want_digest(v, io) contains the hash value |
247 | * for a lower tree level or for the data block (if we're at the lowest level). | |
a4ffc152 MP |
248 | * |
249 | * If "skip_unverified" is true, unverified buffer is skipped and 1 is returned. | |
250 | * If "skip_unverified" is false, unverified buffer is hashed and verified | |
ffa39380 | 251 | * against current value of verity_io_want_digest(v, io). |
a4ffc152 | 252 | */ |
6dbeda34 ST |
253 | static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io, |
254 | sector_t block, int level, bool skip_unverified, | |
255 | u8 *want_digest) | |
a4ffc152 | 256 | { |
a4ffc152 MP |
257 | struct dm_buffer *buf; |
258 | struct buffer_aux *aux; | |
259 | u8 *data; | |
260 | int r; | |
261 | sector_t hash_block; | |
262 | unsigned offset; | |
263 | ||
264 | verity_hash_at_level(v, block, level, &hash_block, &offset); | |
265 | ||
266 | data = dm_bufio_read(v->bufio, hash_block, &buf); | |
fc0a4461 | 267 | if (IS_ERR(data)) |
a4ffc152 MP |
268 | return PTR_ERR(data); |
269 | ||
270 | aux = dm_bufio_get_aux_data(buf); | |
271 | ||
272 | if (!aux->hash_verified) { | |
a4ffc152 MP |
273 | if (skip_unverified) { |
274 | r = 1; | |
275 | goto release_ret_r; | |
276 | } | |
277 | ||
ffa39380 | 278 | r = verity_hash(v, verity_io_hash_desc(v, io), |
6dbeda34 | 279 | data, 1 << v->hash_dev_block_bits, |
ffa39380 | 280 | verity_io_real_digest(v, io)); |
6dbeda34 | 281 | if (unlikely(r < 0)) |
a4ffc152 | 282 | goto release_ret_r; |
a4ffc152 | 283 | |
ffa39380 | 284 | if (likely(memcmp(verity_io_real_digest(v, io), want_digest, |
6dbeda34 ST |
285 | v->digest_size) == 0)) |
286 | aux->hash_verified = 1; | |
a739ff3f ST |
287 | else if (verity_fec_decode(v, io, |
288 | DM_VERITY_BLOCK_TYPE_METADATA, | |
289 | hash_block, data, NULL) == 0) | |
290 | aux->hash_verified = 1; | |
6dbeda34 ST |
291 | else if (verity_handle_err(v, |
292 | DM_VERITY_BLOCK_TYPE_METADATA, | |
293 | hash_block)) { | |
294 | r = -EIO; | |
a4ffc152 MP |
295 | goto release_ret_r; |
296 | } | |
a4ffc152 MP |
297 | } |
298 | ||
299 | data += offset; | |
6dbeda34 ST |
300 | memcpy(want_digest, data, v->digest_size); |
301 | r = 0; | |
a4ffc152 MP |
302 | |
303 | release_ret_r: | |
304 | dm_bufio_release(buf); | |
a4ffc152 MP |
305 | return r; |
306 | } | |
307 | ||
6dbeda34 ST |
308 | /* |
309 | * Find a hash for a given block, write it to digest and verify the integrity | |
310 | * of the hash tree if necessary. | |
311 | */ | |
ffa39380 | 312 | int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, |
0cc37c2d | 313 | sector_t block, u8 *digest, bool *is_zero) |
6dbeda34 | 314 | { |
0cc37c2d | 315 | int r = 0, i; |
6dbeda34 ST |
316 | |
317 | if (likely(v->levels)) { | |
318 | /* | |
319 | * First, we try to get the requested hash for | |
320 | * the current block. If the hash block itself is | |
321 | * verified, zero is returned. If it isn't, this | |
322 | * function returns 1 and we fall back to whole | |
323 | * chain verification. | |
324 | */ | |
325 | r = verity_verify_level(v, io, block, 0, true, digest); | |
326 | if (likely(r <= 0)) | |
0cc37c2d | 327 | goto out; |
6dbeda34 ST |
328 | } |
329 | ||
330 | memcpy(digest, v->root_digest, v->digest_size); | |
331 | ||
332 | for (i = v->levels - 1; i >= 0; i--) { | |
333 | r = verity_verify_level(v, io, block, i, false, digest); | |
334 | if (unlikely(r)) | |
0cc37c2d | 335 | goto out; |
6dbeda34 | 336 | } |
0cc37c2d ST |
337 | out: |
338 | if (!r && v->zero_digest) | |
339 | *is_zero = !memcmp(v->zero_digest, digest, v->digest_size); | |
340 | else | |
341 | *is_zero = false; | |
6dbeda34 | 342 | |
0cc37c2d | 343 | return r; |
6dbeda34 ST |
344 | } |
345 | ||
bb4d73ac ST |
346 | /* |
347 | * Calls function process for 1 << v->data_dev_block_bits bytes in the bio_vec | |
348 | * starting from iter. | |
349 | */ | |
350 | int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io, | |
351 | struct bvec_iter *iter, | |
352 | int (*process)(struct dm_verity *v, | |
353 | struct dm_verity_io *io, u8 *data, | |
354 | size_t len)) | |
355 | { | |
356 | unsigned todo = 1 << v->data_dev_block_bits; | |
30187e1d | 357 | struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size); |
bb4d73ac ST |
358 | |
359 | do { | |
360 | int r; | |
361 | u8 *page; | |
362 | unsigned len; | |
363 | struct bio_vec bv = bio_iter_iovec(bio, *iter); | |
364 | ||
365 | page = kmap_atomic(bv.bv_page); | |
366 | len = bv.bv_len; | |
367 | ||
368 | if (likely(len >= todo)) | |
369 | len = todo; | |
370 | ||
371 | r = process(v, io, page + bv.bv_offset, len); | |
372 | kunmap_atomic(page); | |
373 | ||
374 | if (r < 0) | |
375 | return r; | |
376 | ||
377 | bio_advance_iter(bio, iter, len); | |
378 | todo -= len; | |
379 | } while (todo); | |
380 | ||
381 | return 0; | |
382 | } | |
383 | ||
384 | static int verity_bv_hash_update(struct dm_verity *v, struct dm_verity_io *io, | |
385 | u8 *data, size_t len) | |
386 | { | |
387 | return verity_hash_update(v, verity_io_hash_desc(v, io), data, len); | |
388 | } | |
389 | ||
0cc37c2d ST |
390 | static int verity_bv_zero(struct dm_verity *v, struct dm_verity_io *io, |
391 | u8 *data, size_t len) | |
392 | { | |
393 | memset(data, 0, len); | |
394 | return 0; | |
395 | } | |
396 | ||
a4ffc152 MP |
397 | /* |
398 | * Verify one "dm_verity_io" structure. | |
399 | */ | |
400 | static int verity_verify_io(struct dm_verity_io *io) | |
401 | { | |
0cc37c2d | 402 | bool is_zero; |
a4ffc152 | 403 | struct dm_verity *v = io->v; |
bb4d73ac | 404 | struct bvec_iter start; |
a4ffc152 | 405 | unsigned b; |
a4ffc152 MP |
406 | |
407 | for (b = 0; b < io->n_blocks; b++) { | |
a4ffc152 | 408 | int r; |
ffa39380 | 409 | struct shash_desc *desc = verity_io_hash_desc(v, io); |
a4ffc152 | 410 | |
6dbeda34 | 411 | r = verity_hash_for_block(v, io, io->block + b, |
0cc37c2d ST |
412 | verity_io_want_digest(v, io), |
413 | &is_zero); | |
6dbeda34 ST |
414 | if (unlikely(r < 0)) |
415 | return r; | |
a4ffc152 | 416 | |
0cc37c2d ST |
417 | if (is_zero) { |
418 | /* | |
419 | * If we expect a zero block, don't validate, just | |
420 | * return zeros. | |
421 | */ | |
422 | r = verity_for_bv_block(v, io, &io->iter, | |
423 | verity_bv_zero); | |
424 | if (unlikely(r < 0)) | |
425 | return r; | |
426 | ||
427 | continue; | |
428 | } | |
429 | ||
6dbeda34 ST |
430 | r = verity_hash_init(v, desc); |
431 | if (unlikely(r < 0)) | |
a4ffc152 | 432 | return r; |
a4ffc152 | 433 | |
bb4d73ac ST |
434 | start = io->iter; |
435 | r = verity_for_bv_block(v, io, &io->iter, verity_bv_hash_update); | |
436 | if (unlikely(r < 0)) | |
437 | return r; | |
a4ffc152 | 438 | |
ffa39380 | 439 | r = verity_hash_final(v, desc, verity_io_real_digest(v, io)); |
6dbeda34 | 440 | if (unlikely(r < 0)) |
a4ffc152 | 441 | return r; |
6dbeda34 | 442 | |
ffa39380 ST |
443 | if (likely(memcmp(verity_io_real_digest(v, io), |
444 | verity_io_want_digest(v, io), v->digest_size) == 0)) | |
6dbeda34 | 445 | continue; |
a739ff3f ST |
446 | else if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_DATA, |
447 | io->block + b, NULL, &start) == 0) | |
448 | continue; | |
6dbeda34 | 449 | else if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA, |
a739ff3f | 450 | io->block + b)) |
6dbeda34 | 451 | return -EIO; |
a4ffc152 | 452 | } |
a4ffc152 MP |
453 | |
454 | return 0; | |
455 | } | |
456 | ||
457 | /* | |
458 | * End one "io" structure with a given error. | |
459 | */ | |
460 | static void verity_finish_io(struct dm_verity_io *io, int error) | |
461 | { | |
a4ffc152 | 462 | struct dm_verity *v = io->v; |
30187e1d | 463 | struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size); |
a4ffc152 MP |
464 | |
465 | bio->bi_end_io = io->orig_bi_end_io; | |
4246a0b6 | 466 | bio->bi_error = error; |
a4ffc152 | 467 | |
a739ff3f ST |
468 | verity_fec_finish_io(io); |
469 | ||
4246a0b6 | 470 | bio_endio(bio); |
a4ffc152 MP |
471 | } |
472 | ||
473 | static void verity_work(struct work_struct *w) | |
474 | { | |
475 | struct dm_verity_io *io = container_of(w, struct dm_verity_io, work); | |
476 | ||
477 | verity_finish_io(io, verity_verify_io(io)); | |
478 | } | |
479 | ||
4246a0b6 | 480 | static void verity_end_io(struct bio *bio) |
a4ffc152 MP |
481 | { |
482 | struct dm_verity_io *io = bio->bi_private; | |
483 | ||
a739ff3f | 484 | if (bio->bi_error && !verity_fec_is_enabled(io->v)) { |
4246a0b6 | 485 | verity_finish_io(io, bio->bi_error); |
a4ffc152 MP |
486 | return; |
487 | } | |
488 | ||
489 | INIT_WORK(&io->work, verity_work); | |
490 | queue_work(io->v->verify_wq, &io->work); | |
491 | } | |
492 | ||
493 | /* | |
494 | * Prefetch buffers for the specified io. | |
495 | * The root buffer is not prefetched, it is assumed that it will be cached | |
496 | * all the time. | |
497 | */ | |
3b6b7813 | 498 | static void verity_prefetch_io(struct work_struct *work) |
a4ffc152 | 499 | { |
3b6b7813 MP |
500 | struct dm_verity_prefetch_work *pw = |
501 | container_of(work, struct dm_verity_prefetch_work, work); | |
502 | struct dm_verity *v = pw->v; | |
a4ffc152 MP |
503 | int i; |
504 | ||
505 | for (i = v->levels - 2; i >= 0; i--) { | |
506 | sector_t hash_block_start; | |
507 | sector_t hash_block_end; | |
3b6b7813 MP |
508 | verity_hash_at_level(v, pw->block, i, &hash_block_start, NULL); |
509 | verity_hash_at_level(v, pw->block + pw->n_blocks - 1, i, &hash_block_end, NULL); | |
a4ffc152 | 510 | if (!i) { |
fe5fe906 | 511 | unsigned cluster = ACCESS_ONCE(dm_verity_prefetch_cluster); |
a4ffc152 MP |
512 | |
513 | cluster >>= v->data_dev_block_bits; | |
514 | if (unlikely(!cluster)) | |
515 | goto no_prefetch_cluster; | |
516 | ||
517 | if (unlikely(cluster & (cluster - 1))) | |
553d8fe0 | 518 | cluster = 1 << __fls(cluster); |
a4ffc152 MP |
519 | |
520 | hash_block_start &= ~(sector_t)(cluster - 1); | |
521 | hash_block_end |= cluster - 1; | |
522 | if (unlikely(hash_block_end >= v->hash_blocks)) | |
523 | hash_block_end = v->hash_blocks - 1; | |
524 | } | |
525 | no_prefetch_cluster: | |
526 | dm_bufio_prefetch(v->bufio, hash_block_start, | |
527 | hash_block_end - hash_block_start + 1); | |
528 | } | |
3b6b7813 MP |
529 | |
530 | kfree(pw); | |
531 | } | |
532 | ||
533 | static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io) | |
534 | { | |
535 | struct dm_verity_prefetch_work *pw; | |
536 | ||
537 | pw = kmalloc(sizeof(struct dm_verity_prefetch_work), | |
538 | GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); | |
539 | ||
540 | if (!pw) | |
541 | return; | |
542 | ||
543 | INIT_WORK(&pw->work, verity_prefetch_io); | |
544 | pw->v = v; | |
545 | pw->block = io->block; | |
546 | pw->n_blocks = io->n_blocks; | |
547 | queue_work(v->verify_wq, &pw->work); | |
a4ffc152 MP |
548 | } |
549 | ||
550 | /* | |
551 | * Bio map function. It allocates dm_verity_io structure and bio vector and | |
552 | * fills them. Then it issues prefetches and the I/O. | |
553 | */ | |
7de3ee57 | 554 | static int verity_map(struct dm_target *ti, struct bio *bio) |
a4ffc152 MP |
555 | { |
556 | struct dm_verity *v = ti->private; | |
557 | struct dm_verity_io *io; | |
558 | ||
559 | bio->bi_bdev = v->data_dev->bdev; | |
4f024f37 | 560 | bio->bi_iter.bi_sector = verity_map_sector(v, bio->bi_iter.bi_sector); |
a4ffc152 | 561 | |
4f024f37 | 562 | if (((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) & |
a4ffc152 MP |
563 | ((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) { |
564 | DMERR_LIMIT("unaligned io"); | |
565 | return -EIO; | |
566 | } | |
567 | ||
f73a1c7d | 568 | if (bio_end_sector(bio) >> |
a4ffc152 MP |
569 | (v->data_dev_block_bits - SECTOR_SHIFT) > v->data_blocks) { |
570 | DMERR_LIMIT("io out of range"); | |
571 | return -EIO; | |
572 | } | |
573 | ||
574 | if (bio_data_dir(bio) == WRITE) | |
575 | return -EIO; | |
576 | ||
30187e1d | 577 | io = dm_per_bio_data(bio, ti->per_io_data_size); |
a4ffc152 | 578 | io->v = v; |
a4ffc152 | 579 | io->orig_bi_end_io = bio->bi_end_io; |
4f024f37 KO |
580 | io->block = bio->bi_iter.bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT); |
581 | io->n_blocks = bio->bi_iter.bi_size >> v->data_dev_block_bits; | |
a4ffc152 MP |
582 | |
583 | bio->bi_end_io = verity_end_io; | |
584 | bio->bi_private = io; | |
003b5c57 | 585 | io->iter = bio->bi_iter; |
a4ffc152 | 586 | |
a739ff3f ST |
587 | verity_fec_init_io(io); |
588 | ||
3b6b7813 | 589 | verity_submit_prefetch(v, io); |
a4ffc152 MP |
590 | |
591 | generic_make_request(bio); | |
592 | ||
593 | return DM_MAPIO_SUBMITTED; | |
594 | } | |
595 | ||
596 | /* | |
597 | * Status: V (valid) or C (corruption found) | |
598 | */ | |
fd7c092e MP |
599 | static void verity_status(struct dm_target *ti, status_type_t type, |
600 | unsigned status_flags, char *result, unsigned maxlen) | |
a4ffc152 MP |
601 | { |
602 | struct dm_verity *v = ti->private; | |
a739ff3f | 603 | unsigned args = 0; |
a4ffc152 MP |
604 | unsigned sz = 0; |
605 | unsigned x; | |
606 | ||
607 | switch (type) { | |
608 | case STATUSTYPE_INFO: | |
609 | DMEMIT("%c", v->hash_failed ? 'C' : 'V'); | |
610 | break; | |
611 | case STATUSTYPE_TABLE: | |
612 | DMEMIT("%u %s %s %u %u %llu %llu %s ", | |
613 | v->version, | |
614 | v->data_dev->name, | |
615 | v->hash_dev->name, | |
616 | 1 << v->data_dev_block_bits, | |
617 | 1 << v->hash_dev_block_bits, | |
618 | (unsigned long long)v->data_blocks, | |
619 | (unsigned long long)v->hash_start, | |
620 | v->alg_name | |
621 | ); | |
622 | for (x = 0; x < v->digest_size; x++) | |
623 | DMEMIT("%02x", v->root_digest[x]); | |
624 | DMEMIT(" "); | |
625 | if (!v->salt_size) | |
626 | DMEMIT("-"); | |
627 | else | |
628 | for (x = 0; x < v->salt_size; x++) | |
629 | DMEMIT("%02x", v->salt[x]); | |
a739ff3f ST |
630 | if (v->mode != DM_VERITY_MODE_EIO) |
631 | args++; | |
632 | if (verity_fec_is_enabled(v)) | |
633 | args += DM_VERITY_OPTS_FEC; | |
0cc37c2d ST |
634 | if (v->zero_digest) |
635 | args++; | |
a739ff3f ST |
636 | if (!args) |
637 | return; | |
638 | DMEMIT(" %u", args); | |
65ff5b7d | 639 | if (v->mode != DM_VERITY_MODE_EIO) { |
a739ff3f | 640 | DMEMIT(" "); |
65ff5b7d ST |
641 | switch (v->mode) { |
642 | case DM_VERITY_MODE_LOGGING: | |
643 | DMEMIT(DM_VERITY_OPT_LOGGING); | |
644 | break; | |
645 | case DM_VERITY_MODE_RESTART: | |
646 | DMEMIT(DM_VERITY_OPT_RESTART); | |
647 | break; | |
648 | default: | |
649 | BUG(); | |
650 | } | |
651 | } | |
0cc37c2d ST |
652 | if (v->zero_digest) |
653 | DMEMIT(" " DM_VERITY_OPT_IGN_ZEROES); | |
a739ff3f | 654 | sz = verity_fec_status_table(v, sz, result, maxlen); |
a4ffc152 MP |
655 | break; |
656 | } | |
a4ffc152 MP |
657 | } |
658 | ||
e56f81e0 CH |
659 | static int verity_prepare_ioctl(struct dm_target *ti, |
660 | struct block_device **bdev, fmode_t *mode) | |
a4ffc152 MP |
661 | { |
662 | struct dm_verity *v = ti->private; | |
e56f81e0 CH |
663 | |
664 | *bdev = v->data_dev->bdev; | |
a4ffc152 MP |
665 | |
666 | if (v->data_start || | |
667 | ti->len != i_size_read(v->data_dev->bdev->bd_inode) >> SECTOR_SHIFT) | |
e56f81e0 CH |
668 | return 1; |
669 | return 0; | |
a4ffc152 MP |
670 | } |
671 | ||
a4ffc152 MP |
672 | static int verity_iterate_devices(struct dm_target *ti, |
673 | iterate_devices_callout_fn fn, void *data) | |
674 | { | |
675 | struct dm_verity *v = ti->private; | |
676 | ||
677 | return fn(ti, v->data_dev, v->data_start, ti->len, data); | |
678 | } | |
679 | ||
680 | static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits) | |
681 | { | |
682 | struct dm_verity *v = ti->private; | |
683 | ||
684 | if (limits->logical_block_size < 1 << v->data_dev_block_bits) | |
685 | limits->logical_block_size = 1 << v->data_dev_block_bits; | |
686 | ||
687 | if (limits->physical_block_size < 1 << v->data_dev_block_bits) | |
688 | limits->physical_block_size = 1 << v->data_dev_block_bits; | |
689 | ||
690 | blk_limits_io_min(limits, limits->logical_block_size); | |
691 | } | |
692 | ||
693 | static void verity_dtr(struct dm_target *ti) | |
694 | { | |
695 | struct dm_verity *v = ti->private; | |
696 | ||
697 | if (v->verify_wq) | |
698 | destroy_workqueue(v->verify_wq); | |
699 | ||
a4ffc152 MP |
700 | if (v->bufio) |
701 | dm_bufio_client_destroy(v->bufio); | |
702 | ||
703 | kfree(v->salt); | |
704 | kfree(v->root_digest); | |
0cc37c2d | 705 | kfree(v->zero_digest); |
a4ffc152 MP |
706 | |
707 | if (v->tfm) | |
708 | crypto_free_shash(v->tfm); | |
709 | ||
710 | kfree(v->alg_name); | |
711 | ||
712 | if (v->hash_dev) | |
713 | dm_put_device(ti, v->hash_dev); | |
714 | ||
715 | if (v->data_dev) | |
716 | dm_put_device(ti, v->data_dev); | |
717 | ||
a739ff3f ST |
718 | verity_fec_dtr(v); |
719 | ||
a4ffc152 MP |
720 | kfree(v); |
721 | } | |
722 | ||
0cc37c2d ST |
723 | static int verity_alloc_zero_digest(struct dm_verity *v) |
724 | { | |
725 | int r = -ENOMEM; | |
726 | struct shash_desc *desc; | |
727 | u8 *zero_data; | |
728 | ||
729 | v->zero_digest = kmalloc(v->digest_size, GFP_KERNEL); | |
730 | ||
731 | if (!v->zero_digest) | |
732 | return r; | |
733 | ||
734 | desc = kmalloc(v->shash_descsize, GFP_KERNEL); | |
735 | ||
736 | if (!desc) | |
737 | return r; /* verity_dtr will free zero_digest */ | |
738 | ||
739 | zero_data = kzalloc(1 << v->data_dev_block_bits, GFP_KERNEL); | |
740 | ||
741 | if (!zero_data) | |
742 | goto out; | |
743 | ||
744 | r = verity_hash(v, desc, zero_data, 1 << v->data_dev_block_bits, | |
745 | v->zero_digest); | |
746 | ||
747 | out: | |
748 | kfree(desc); | |
749 | kfree(zero_data); | |
750 | ||
751 | return r; | |
752 | } | |
753 | ||
753c1fd0 ST |
754 | static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v) |
755 | { | |
756 | int r; | |
757 | unsigned argc; | |
758 | struct dm_target *ti = v->ti; | |
759 | const char *arg_name; | |
760 | ||
761 | static struct dm_arg _args[] = { | |
762 | {0, DM_VERITY_OPTS_MAX, "Invalid number of feature args"}, | |
763 | }; | |
764 | ||
765 | r = dm_read_arg_group(_args, as, &argc, &ti->error); | |
766 | if (r) | |
767 | return -EINVAL; | |
768 | ||
769 | if (!argc) | |
770 | return 0; | |
771 | ||
772 | do { | |
773 | arg_name = dm_shift_arg(as); | |
774 | argc--; | |
775 | ||
776 | if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING)) { | |
777 | v->mode = DM_VERITY_MODE_LOGGING; | |
778 | continue; | |
779 | ||
780 | } else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART)) { | |
781 | v->mode = DM_VERITY_MODE_RESTART; | |
782 | continue; | |
a739ff3f | 783 | |
0cc37c2d ST |
784 | } else if (!strcasecmp(arg_name, DM_VERITY_OPT_IGN_ZEROES)) { |
785 | r = verity_alloc_zero_digest(v); | |
786 | if (r) { | |
787 | ti->error = "Cannot allocate zero digest"; | |
788 | return r; | |
789 | } | |
790 | continue; | |
791 | ||
a739ff3f ST |
792 | } else if (verity_is_fec_opt_arg(arg_name)) { |
793 | r = verity_fec_parse_opt_args(as, v, &argc, arg_name); | |
794 | if (r) | |
795 | return r; | |
796 | continue; | |
753c1fd0 ST |
797 | } |
798 | ||
799 | ti->error = "Unrecognized verity feature request"; | |
800 | return -EINVAL; | |
801 | } while (argc && !r); | |
802 | ||
803 | return r; | |
804 | } | |
805 | ||
a4ffc152 MP |
806 | /* |
807 | * Target parameters: | |
808 | * <version> The current format is version 1. | |
809 | * Vsn 0 is compatible with original Chromium OS releases. | |
810 | * <data device> | |
811 | * <hash device> | |
812 | * <data block size> | |
813 | * <hash block size> | |
814 | * <the number of data blocks> | |
815 | * <hash start block> | |
816 | * <algorithm> | |
817 | * <digest> | |
818 | * <salt> Hex string or "-" if no salt. | |
819 | */ | |
820 | static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) | |
821 | { | |
822 | struct dm_verity *v; | |
65ff5b7d | 823 | struct dm_arg_set as; |
753c1fd0 | 824 | unsigned int num; |
a4ffc152 MP |
825 | unsigned long long num_ll; |
826 | int r; | |
827 | int i; | |
828 | sector_t hash_position; | |
829 | char dummy; | |
830 | ||
831 | v = kzalloc(sizeof(struct dm_verity), GFP_KERNEL); | |
832 | if (!v) { | |
833 | ti->error = "Cannot allocate verity structure"; | |
834 | return -ENOMEM; | |
835 | } | |
836 | ti->private = v; | |
837 | v->ti = ti; | |
838 | ||
a739ff3f ST |
839 | r = verity_fec_ctr_alloc(v); |
840 | if (r) | |
841 | goto bad; | |
842 | ||
a4ffc152 MP |
843 | if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) { |
844 | ti->error = "Device must be readonly"; | |
845 | r = -EINVAL; | |
846 | goto bad; | |
847 | } | |
848 | ||
65ff5b7d ST |
849 | if (argc < 10) { |
850 | ti->error = "Not enough arguments"; | |
a4ffc152 MP |
851 | r = -EINVAL; |
852 | goto bad; | |
853 | } | |
854 | ||
5d8be843 MP |
855 | if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 || |
856 | num > 1) { | |
a4ffc152 MP |
857 | ti->error = "Invalid version"; |
858 | r = -EINVAL; | |
859 | goto bad; | |
860 | } | |
861 | v->version = num; | |
862 | ||
863 | r = dm_get_device(ti, argv[1], FMODE_READ, &v->data_dev); | |
864 | if (r) { | |
865 | ti->error = "Data device lookup failed"; | |
866 | goto bad; | |
867 | } | |
868 | ||
869 | r = dm_get_device(ti, argv[2], FMODE_READ, &v->hash_dev); | |
870 | if (r) { | |
871 | ti->error = "Data device lookup failed"; | |
872 | goto bad; | |
873 | } | |
874 | ||
875 | if (sscanf(argv[3], "%u%c", &num, &dummy) != 1 || | |
876 | !num || (num & (num - 1)) || | |
877 | num < bdev_logical_block_size(v->data_dev->bdev) || | |
878 | num > PAGE_SIZE) { | |
879 | ti->error = "Invalid data device block size"; | |
880 | r = -EINVAL; | |
881 | goto bad; | |
882 | } | |
553d8fe0 | 883 | v->data_dev_block_bits = __ffs(num); |
a4ffc152 MP |
884 | |
885 | if (sscanf(argv[4], "%u%c", &num, &dummy) != 1 || | |
886 | !num || (num & (num - 1)) || | |
887 | num < bdev_logical_block_size(v->hash_dev->bdev) || | |
888 | num > INT_MAX) { | |
889 | ti->error = "Invalid hash device block size"; | |
890 | r = -EINVAL; | |
891 | goto bad; | |
892 | } | |
553d8fe0 | 893 | v->hash_dev_block_bits = __ffs(num); |
a4ffc152 MP |
894 | |
895 | if (sscanf(argv[5], "%llu%c", &num_ll, &dummy) != 1 || | |
1d55f6bc MP |
896 | (sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT)) |
897 | >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll) { | |
a4ffc152 MP |
898 | ti->error = "Invalid data blocks"; |
899 | r = -EINVAL; | |
900 | goto bad; | |
901 | } | |
902 | v->data_blocks = num_ll; | |
903 | ||
904 | if (ti->len > (v->data_blocks << (v->data_dev_block_bits - SECTOR_SHIFT))) { | |
905 | ti->error = "Data device is too small"; | |
906 | r = -EINVAL; | |
907 | goto bad; | |
908 | } | |
909 | ||
910 | if (sscanf(argv[6], "%llu%c", &num_ll, &dummy) != 1 || | |
1d55f6bc MP |
911 | (sector_t)(num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT)) |
912 | >> (v->hash_dev_block_bits - SECTOR_SHIFT) != num_ll) { | |
a4ffc152 MP |
913 | ti->error = "Invalid hash start"; |
914 | r = -EINVAL; | |
915 | goto bad; | |
916 | } | |
917 | v->hash_start = num_ll; | |
918 | ||
919 | v->alg_name = kstrdup(argv[7], GFP_KERNEL); | |
920 | if (!v->alg_name) { | |
921 | ti->error = "Cannot allocate algorithm name"; | |
922 | r = -ENOMEM; | |
923 | goto bad; | |
924 | } | |
925 | ||
926 | v->tfm = crypto_alloc_shash(v->alg_name, 0, 0); | |
927 | if (IS_ERR(v->tfm)) { | |
928 | ti->error = "Cannot initialize hash function"; | |
929 | r = PTR_ERR(v->tfm); | |
930 | v->tfm = NULL; | |
931 | goto bad; | |
932 | } | |
933 | v->digest_size = crypto_shash_digestsize(v->tfm); | |
934 | if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) { | |
935 | ti->error = "Digest size too big"; | |
936 | r = -EINVAL; | |
937 | goto bad; | |
938 | } | |
939 | v->shash_descsize = | |
940 | sizeof(struct shash_desc) + crypto_shash_descsize(v->tfm); | |
941 | ||
942 | v->root_digest = kmalloc(v->digest_size, GFP_KERNEL); | |
943 | if (!v->root_digest) { | |
944 | ti->error = "Cannot allocate root digest"; | |
945 | r = -ENOMEM; | |
946 | goto bad; | |
947 | } | |
948 | if (strlen(argv[8]) != v->digest_size * 2 || | |
949 | hex2bin(v->root_digest, argv[8], v->digest_size)) { | |
950 | ti->error = "Invalid root digest"; | |
951 | r = -EINVAL; | |
952 | goto bad; | |
953 | } | |
954 | ||
955 | if (strcmp(argv[9], "-")) { | |
956 | v->salt_size = strlen(argv[9]) / 2; | |
957 | v->salt = kmalloc(v->salt_size, GFP_KERNEL); | |
958 | if (!v->salt) { | |
959 | ti->error = "Cannot allocate salt"; | |
960 | r = -ENOMEM; | |
961 | goto bad; | |
962 | } | |
963 | if (strlen(argv[9]) != v->salt_size * 2 || | |
964 | hex2bin(v->salt, argv[9], v->salt_size)) { | |
965 | ti->error = "Invalid salt"; | |
966 | r = -EINVAL; | |
967 | goto bad; | |
968 | } | |
969 | } | |
970 | ||
65ff5b7d ST |
971 | argv += 10; |
972 | argc -= 10; | |
973 | ||
974 | /* Optional parameters */ | |
975 | if (argc) { | |
976 | as.argc = argc; | |
977 | as.argv = argv; | |
978 | ||
753c1fd0 ST |
979 | r = verity_parse_opt_args(&as, v); |
980 | if (r < 0) | |
65ff5b7d | 981 | goto bad; |
65ff5b7d ST |
982 | } |
983 | ||
a4ffc152 | 984 | v->hash_per_block_bits = |
553d8fe0 | 985 | __fls((1 << v->hash_dev_block_bits) / v->digest_size); |
a4ffc152 MP |
986 | |
987 | v->levels = 0; | |
988 | if (v->data_blocks) | |
989 | while (v->hash_per_block_bits * v->levels < 64 && | |
990 | (unsigned long long)(v->data_blocks - 1) >> | |
991 | (v->hash_per_block_bits * v->levels)) | |
992 | v->levels++; | |
993 | ||
994 | if (v->levels > DM_VERITY_MAX_LEVELS) { | |
995 | ti->error = "Too many tree levels"; | |
996 | r = -E2BIG; | |
997 | goto bad; | |
998 | } | |
999 | ||
1000 | hash_position = v->hash_start; | |
1001 | for (i = v->levels - 1; i >= 0; i--) { | |
1002 | sector_t s; | |
1003 | v->hash_level_block[i] = hash_position; | |
b1bf2de0 MP |
1004 | s = (v->data_blocks + ((sector_t)1 << ((i + 1) * v->hash_per_block_bits)) - 1) |
1005 | >> ((i + 1) * v->hash_per_block_bits); | |
a4ffc152 MP |
1006 | if (hash_position + s < hash_position) { |
1007 | ti->error = "Hash device offset overflow"; | |
1008 | r = -E2BIG; | |
1009 | goto bad; | |
1010 | } | |
1011 | hash_position += s; | |
1012 | } | |
1013 | v->hash_blocks = hash_position; | |
1014 | ||
1015 | v->bufio = dm_bufio_client_create(v->hash_dev->bdev, | |
1016 | 1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux), | |
1017 | dm_bufio_alloc_callback, NULL); | |
1018 | if (IS_ERR(v->bufio)) { | |
1019 | ti->error = "Cannot initialize dm-bufio"; | |
1020 | r = PTR_ERR(v->bufio); | |
1021 | v->bufio = NULL; | |
1022 | goto bad; | |
1023 | } | |
1024 | ||
1025 | if (dm_bufio_get_device_size(v->bufio) < v->hash_blocks) { | |
1026 | ti->error = "Hash device is too small"; | |
1027 | r = -E2BIG; | |
1028 | goto bad; | |
1029 | } | |
1030 | ||
a4ffc152 MP |
1031 | /* WQ_UNBOUND greatly improves performance when running on ramdisk */ |
1032 | v->verify_wq = alloc_workqueue("kverityd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND, num_online_cpus()); | |
1033 | if (!v->verify_wq) { | |
1034 | ti->error = "Cannot allocate workqueue"; | |
1035 | r = -ENOMEM; | |
1036 | goto bad; | |
1037 | } | |
1038 | ||
30187e1d | 1039 | ti->per_io_data_size = sizeof(struct dm_verity_io) + |
a739ff3f ST |
1040 | v->shash_descsize + v->digest_size * 2; |
1041 | ||
1042 | r = verity_fec_ctr(v); | |
1043 | if (r) | |
1044 | goto bad; | |
1045 | ||
30187e1d MS |
1046 | ti->per_io_data_size = roundup(ti->per_io_data_size, |
1047 | __alignof__(struct dm_verity_io)); | |
a739ff3f | 1048 | |
a4ffc152 MP |
1049 | return 0; |
1050 | ||
1051 | bad: | |
1052 | verity_dtr(ti); | |
1053 | ||
1054 | return r; | |
1055 | } | |
1056 | ||
1057 | static struct target_type verity_target = { | |
1058 | .name = "verity", | |
a739ff3f | 1059 | .version = {1, 3, 0}, |
a4ffc152 MP |
1060 | .module = THIS_MODULE, |
1061 | .ctr = verity_ctr, | |
1062 | .dtr = verity_dtr, | |
1063 | .map = verity_map, | |
1064 | .status = verity_status, | |
e56f81e0 | 1065 | .prepare_ioctl = verity_prepare_ioctl, |
a4ffc152 MP |
1066 | .iterate_devices = verity_iterate_devices, |
1067 | .io_hints = verity_io_hints, | |
1068 | }; | |
1069 | ||
1070 | static int __init dm_verity_init(void) | |
1071 | { | |
1072 | int r; | |
1073 | ||
1074 | r = dm_register_target(&verity_target); | |
1075 | if (r < 0) | |
1076 | DMERR("register failed %d", r); | |
1077 | ||
1078 | return r; | |
1079 | } | |
1080 | ||
1081 | static void __exit dm_verity_exit(void) | |
1082 | { | |
1083 | dm_unregister_target(&verity_target); | |
1084 | } | |
1085 | ||
1086 | module_init(dm_verity_init); | |
1087 | module_exit(dm_verity_exit); | |
1088 | ||
1089 | MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>"); | |
1090 | MODULE_AUTHOR("Mandeep Baines <msb@chromium.org>"); | |
1091 | MODULE_AUTHOR("Will Drewry <wad@chromium.org>"); | |
1092 | MODULE_DESCRIPTION(DM_NAME " target for transparent disk integrity checking"); | |
1093 | MODULE_LICENSE("GPL"); |