]>
Commit | Line | Data |
---|---|---|
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" |
a4ffc152 MP |
18 | |
19 | #include <linux/module.h> | |
65ff5b7d | 20 | #include <linux/reboot.h> |
a4ffc152 MP |
21 | |
22 | #define DM_MSG_PREFIX "verity" | |
23 | ||
65ff5b7d ST |
24 | #define DM_VERITY_ENV_LENGTH 42 |
25 | #define DM_VERITY_ENV_VAR_NAME "DM_VERITY_ERR_BLOCK_NR" | |
26 | ||
a4ffc152 MP |
27 | #define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144 |
28 | ||
65ff5b7d ST |
29 | #define DM_VERITY_MAX_CORRUPTED_ERRS 100 |
30 | ||
31 | #define DM_VERITY_OPT_LOGGING "ignore_corruption" | |
32 | #define DM_VERITY_OPT_RESTART "restart_on_corruption" | |
a4ffc152 | 33 | |
753c1fd0 ST |
34 | #define DM_VERITY_OPTS_MAX 1 |
35 | ||
a4ffc152 MP |
36 | static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE; |
37 | ||
38 | module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR); | |
39 | ||
3b6b7813 MP |
40 | struct dm_verity_prefetch_work { |
41 | struct work_struct work; | |
42 | struct dm_verity *v; | |
43 | sector_t block; | |
44 | unsigned n_blocks; | |
45 | }; | |
46 | ||
a4ffc152 MP |
47 | /* |
48 | * Auxiliary structure appended to each dm-bufio buffer. If the value | |
49 | * hash_verified is nonzero, hash of the block has been verified. | |
50 | * | |
51 | * The variable hash_verified is set to 0 when allocating the buffer, then | |
52 | * it can be changed to 1 and it is never reset to 0 again. | |
53 | * | |
54 | * There is no lock around this value, a race condition can at worst cause | |
55 | * that multiple processes verify the hash of the same buffer simultaneously | |
56 | * and write 1 to hash_verified simultaneously. | |
57 | * This condition is harmless, so we don't need locking. | |
58 | */ | |
59 | struct buffer_aux { | |
60 | int hash_verified; | |
61 | }; | |
62 | ||
63 | /* | |
64 | * Initialize struct buffer_aux for a freshly created buffer. | |
65 | */ | |
66 | static void dm_bufio_alloc_callback(struct dm_buffer *buf) | |
67 | { | |
68 | struct buffer_aux *aux = dm_bufio_get_aux_data(buf); | |
69 | ||
70 | aux->hash_verified = 0; | |
71 | } | |
72 | ||
73 | /* | |
74 | * Translate input sector number to the sector number on the target device. | |
75 | */ | |
76 | static sector_t verity_map_sector(struct dm_verity *v, sector_t bi_sector) | |
77 | { | |
78 | return v->data_start + dm_target_offset(v->ti, bi_sector); | |
79 | } | |
80 | ||
81 | /* | |
82 | * Return hash position of a specified block at a specified tree level | |
83 | * (0 is the lowest level). | |
84 | * The lowest "hash_per_block_bits"-bits of the result denote hash position | |
85 | * inside a hash block. The remaining bits denote location of the hash block. | |
86 | */ | |
87 | static sector_t verity_position_at_level(struct dm_verity *v, sector_t block, | |
88 | int level) | |
89 | { | |
90 | return block >> (level * v->hash_per_block_bits); | |
91 | } | |
92 | ||
6dbeda34 ST |
93 | /* |
94 | * Wrapper for crypto_shash_init, which handles verity salting. | |
95 | */ | |
96 | static int verity_hash_init(struct dm_verity *v, struct shash_desc *desc) | |
97 | { | |
98 | int r; | |
99 | ||
100 | desc->tfm = v->tfm; | |
101 | desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; | |
102 | ||
103 | r = crypto_shash_init(desc); | |
104 | ||
105 | if (unlikely(r < 0)) { | |
106 | DMERR("crypto_shash_init failed: %d", r); | |
107 | return r; | |
108 | } | |
109 | ||
110 | if (likely(v->version >= 1)) { | |
111 | r = crypto_shash_update(desc, v->salt, v->salt_size); | |
112 | ||
113 | if (unlikely(r < 0)) { | |
114 | DMERR("crypto_shash_update failed: %d", r); | |
115 | return r; | |
116 | } | |
117 | } | |
118 | ||
119 | return 0; | |
120 | } | |
121 | ||
122 | static int verity_hash_update(struct dm_verity *v, struct shash_desc *desc, | |
123 | const u8 *data, size_t len) | |
124 | { | |
125 | int r = crypto_shash_update(desc, data, len); | |
126 | ||
127 | if (unlikely(r < 0)) | |
128 | DMERR("crypto_shash_update failed: %d", r); | |
129 | ||
130 | return r; | |
131 | } | |
132 | ||
133 | static int verity_hash_final(struct dm_verity *v, struct shash_desc *desc, | |
134 | u8 *digest) | |
135 | { | |
136 | int r; | |
137 | ||
138 | if (unlikely(!v->version)) { | |
139 | r = crypto_shash_update(desc, v->salt, v->salt_size); | |
140 | ||
141 | if (r < 0) { | |
142 | DMERR("crypto_shash_update failed: %d", r); | |
143 | return r; | |
144 | } | |
145 | } | |
146 | ||
147 | r = crypto_shash_final(desc, digest); | |
148 | ||
149 | if (unlikely(r < 0)) | |
150 | DMERR("crypto_shash_final failed: %d", r); | |
151 | ||
152 | return r; | |
153 | } | |
154 | ||
ffa39380 ST |
155 | int verity_hash(struct dm_verity *v, struct shash_desc *desc, |
156 | const u8 *data, size_t len, u8 *digest) | |
6dbeda34 ST |
157 | { |
158 | int r; | |
159 | ||
160 | r = verity_hash_init(v, desc); | |
161 | if (unlikely(r < 0)) | |
162 | return r; | |
163 | ||
164 | r = verity_hash_update(v, desc, data, len); | |
165 | if (unlikely(r < 0)) | |
166 | return r; | |
167 | ||
168 | return verity_hash_final(v, desc, digest); | |
169 | } | |
170 | ||
a4ffc152 MP |
171 | static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level, |
172 | sector_t *hash_block, unsigned *offset) | |
173 | { | |
174 | sector_t position = verity_position_at_level(v, block, level); | |
175 | unsigned idx; | |
176 | ||
177 | *hash_block = v->hash_level_block[level] + (position >> v->hash_per_block_bits); | |
178 | ||
179 | if (!offset) | |
180 | return; | |
181 | ||
182 | idx = position & ((1 << v->hash_per_block_bits) - 1); | |
183 | if (!v->version) | |
184 | *offset = idx * v->digest_size; | |
185 | else | |
186 | *offset = idx << (v->hash_dev_block_bits - v->hash_per_block_bits); | |
187 | } | |
188 | ||
65ff5b7d ST |
189 | /* |
190 | * Handle verification errors. | |
191 | */ | |
192 | static int verity_handle_err(struct dm_verity *v, enum verity_block_type type, | |
193 | unsigned long long block) | |
194 | { | |
195 | char verity_env[DM_VERITY_ENV_LENGTH]; | |
196 | char *envp[] = { verity_env, NULL }; | |
197 | const char *type_str = ""; | |
198 | struct mapped_device *md = dm_table_get_md(v->ti->table); | |
199 | ||
200 | /* Corruption should be visible in device status in all modes */ | |
201 | v->hash_failed = 1; | |
202 | ||
203 | if (v->corrupted_errs >= DM_VERITY_MAX_CORRUPTED_ERRS) | |
204 | goto out; | |
205 | ||
206 | v->corrupted_errs++; | |
207 | ||
208 | switch (type) { | |
209 | case DM_VERITY_BLOCK_TYPE_DATA: | |
210 | type_str = "data"; | |
211 | break; | |
212 | case DM_VERITY_BLOCK_TYPE_METADATA: | |
213 | type_str = "metadata"; | |
214 | break; | |
215 | default: | |
216 | BUG(); | |
217 | } | |
218 | ||
219 | DMERR("%s: %s block %llu is corrupted", v->data_dev->name, type_str, | |
220 | block); | |
221 | ||
222 | if (v->corrupted_errs == DM_VERITY_MAX_CORRUPTED_ERRS) | |
223 | DMERR("%s: reached maximum errors", v->data_dev->name); | |
224 | ||
225 | snprintf(verity_env, DM_VERITY_ENV_LENGTH, "%s=%d,%llu", | |
226 | DM_VERITY_ENV_VAR_NAME, type, block); | |
227 | ||
228 | kobject_uevent_env(&disk_to_dev(dm_disk(md))->kobj, KOBJ_CHANGE, envp); | |
229 | ||
230 | out: | |
231 | if (v->mode == DM_VERITY_MODE_LOGGING) | |
232 | return 0; | |
233 | ||
234 | if (v->mode == DM_VERITY_MODE_RESTART) | |
235 | kernel_restart("dm-verity device corrupted"); | |
236 | ||
237 | return 1; | |
238 | } | |
239 | ||
a4ffc152 MP |
240 | /* |
241 | * Verify hash of a metadata block pertaining to the specified data block | |
242 | * ("block" argument) at a specified level ("level" argument). | |
243 | * | |
ffa39380 ST |
244 | * On successful return, verity_io_want_digest(v, io) contains the hash value |
245 | * for a lower tree level or for the data block (if we're at the lowest level). | |
a4ffc152 MP |
246 | * |
247 | * If "skip_unverified" is true, unverified buffer is skipped and 1 is returned. | |
248 | * If "skip_unverified" is false, unverified buffer is hashed and verified | |
ffa39380 | 249 | * against current value of verity_io_want_digest(v, io). |
a4ffc152 | 250 | */ |
6dbeda34 ST |
251 | static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io, |
252 | sector_t block, int level, bool skip_unverified, | |
253 | u8 *want_digest) | |
a4ffc152 | 254 | { |
a4ffc152 MP |
255 | struct dm_buffer *buf; |
256 | struct buffer_aux *aux; | |
257 | u8 *data; | |
258 | int r; | |
259 | sector_t hash_block; | |
260 | unsigned offset; | |
261 | ||
262 | verity_hash_at_level(v, block, level, &hash_block, &offset); | |
263 | ||
264 | data = dm_bufio_read(v->bufio, hash_block, &buf); | |
fc0a4461 | 265 | if (IS_ERR(data)) |
a4ffc152 MP |
266 | return PTR_ERR(data); |
267 | ||
268 | aux = dm_bufio_get_aux_data(buf); | |
269 | ||
270 | if (!aux->hash_verified) { | |
a4ffc152 MP |
271 | if (skip_unverified) { |
272 | r = 1; | |
273 | goto release_ret_r; | |
274 | } | |
275 | ||
ffa39380 | 276 | r = verity_hash(v, verity_io_hash_desc(v, io), |
6dbeda34 | 277 | data, 1 << v->hash_dev_block_bits, |
ffa39380 | 278 | verity_io_real_digest(v, io)); |
6dbeda34 | 279 | if (unlikely(r < 0)) |
a4ffc152 | 280 | goto release_ret_r; |
a4ffc152 | 281 | |
ffa39380 | 282 | if (likely(memcmp(verity_io_real_digest(v, io), want_digest, |
6dbeda34 ST |
283 | v->digest_size) == 0)) |
284 | aux->hash_verified = 1; | |
285 | else if (verity_handle_err(v, | |
286 | DM_VERITY_BLOCK_TYPE_METADATA, | |
287 | hash_block)) { | |
288 | r = -EIO; | |
a4ffc152 MP |
289 | goto release_ret_r; |
290 | } | |
a4ffc152 MP |
291 | } |
292 | ||
293 | data += offset; | |
6dbeda34 ST |
294 | memcpy(want_digest, data, v->digest_size); |
295 | r = 0; | |
a4ffc152 MP |
296 | |
297 | release_ret_r: | |
298 | dm_bufio_release(buf); | |
a4ffc152 MP |
299 | return r; |
300 | } | |
301 | ||
6dbeda34 ST |
302 | /* |
303 | * Find a hash for a given block, write it to digest and verify the integrity | |
304 | * of the hash tree if necessary. | |
305 | */ | |
ffa39380 ST |
306 | int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, |
307 | sector_t block, u8 *digest) | |
6dbeda34 ST |
308 | { |
309 | int i; | |
310 | int r; | |
311 | ||
312 | if (likely(v->levels)) { | |
313 | /* | |
314 | * First, we try to get the requested hash for | |
315 | * the current block. If the hash block itself is | |
316 | * verified, zero is returned. If it isn't, this | |
317 | * function returns 1 and we fall back to whole | |
318 | * chain verification. | |
319 | */ | |
320 | r = verity_verify_level(v, io, block, 0, true, digest); | |
321 | if (likely(r <= 0)) | |
322 | return r; | |
323 | } | |
324 | ||
325 | memcpy(digest, v->root_digest, v->digest_size); | |
326 | ||
327 | for (i = v->levels - 1; i >= 0; i--) { | |
328 | r = verity_verify_level(v, io, block, i, false, digest); | |
329 | if (unlikely(r)) | |
330 | return r; | |
331 | } | |
332 | ||
333 | return 0; | |
334 | } | |
335 | ||
bb4d73ac ST |
336 | /* |
337 | * Calls function process for 1 << v->data_dev_block_bits bytes in the bio_vec | |
338 | * starting from iter. | |
339 | */ | |
340 | int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io, | |
341 | struct bvec_iter *iter, | |
342 | int (*process)(struct dm_verity *v, | |
343 | struct dm_verity_io *io, u8 *data, | |
344 | size_t len)) | |
345 | { | |
346 | unsigned todo = 1 << v->data_dev_block_bits; | |
347 | struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_bio_data_size); | |
348 | ||
349 | do { | |
350 | int r; | |
351 | u8 *page; | |
352 | unsigned len; | |
353 | struct bio_vec bv = bio_iter_iovec(bio, *iter); | |
354 | ||
355 | page = kmap_atomic(bv.bv_page); | |
356 | len = bv.bv_len; | |
357 | ||
358 | if (likely(len >= todo)) | |
359 | len = todo; | |
360 | ||
361 | r = process(v, io, page + bv.bv_offset, len); | |
362 | kunmap_atomic(page); | |
363 | ||
364 | if (r < 0) | |
365 | return r; | |
366 | ||
367 | bio_advance_iter(bio, iter, len); | |
368 | todo -= len; | |
369 | } while (todo); | |
370 | ||
371 | return 0; | |
372 | } | |
373 | ||
374 | static int verity_bv_hash_update(struct dm_verity *v, struct dm_verity_io *io, | |
375 | u8 *data, size_t len) | |
376 | { | |
377 | return verity_hash_update(v, verity_io_hash_desc(v, io), data, len); | |
378 | } | |
379 | ||
a4ffc152 MP |
380 | /* |
381 | * Verify one "dm_verity_io" structure. | |
382 | */ | |
383 | static int verity_verify_io(struct dm_verity_io *io) | |
384 | { | |
385 | struct dm_verity *v = io->v; | |
bb4d73ac | 386 | struct bvec_iter start; |
a4ffc152 | 387 | unsigned b; |
a4ffc152 MP |
388 | |
389 | for (b = 0; b < io->n_blocks; b++) { | |
a4ffc152 | 390 | int r; |
ffa39380 | 391 | struct shash_desc *desc = verity_io_hash_desc(v, io); |
a4ffc152 | 392 | |
6dbeda34 | 393 | r = verity_hash_for_block(v, io, io->block + b, |
ffa39380 | 394 | verity_io_want_digest(v, io)); |
6dbeda34 ST |
395 | if (unlikely(r < 0)) |
396 | return r; | |
a4ffc152 | 397 | |
6dbeda34 ST |
398 | r = verity_hash_init(v, desc); |
399 | if (unlikely(r < 0)) | |
a4ffc152 | 400 | return r; |
a4ffc152 | 401 | |
bb4d73ac ST |
402 | start = io->iter; |
403 | r = verity_for_bv_block(v, io, &io->iter, verity_bv_hash_update); | |
404 | if (unlikely(r < 0)) | |
405 | return r; | |
a4ffc152 | 406 | |
ffa39380 | 407 | r = verity_hash_final(v, desc, verity_io_real_digest(v, io)); |
6dbeda34 | 408 | if (unlikely(r < 0)) |
a4ffc152 | 409 | return r; |
6dbeda34 | 410 | |
ffa39380 ST |
411 | if (likely(memcmp(verity_io_real_digest(v, io), |
412 | verity_io_want_digest(v, io), v->digest_size) == 0)) | |
6dbeda34 ST |
413 | continue; |
414 | else if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA, | |
415 | io->block + b)) | |
416 | return -EIO; | |
a4ffc152 | 417 | } |
a4ffc152 MP |
418 | |
419 | return 0; | |
420 | } | |
421 | ||
422 | /* | |
423 | * End one "io" structure with a given error. | |
424 | */ | |
425 | static void verity_finish_io(struct dm_verity_io *io, int error) | |
426 | { | |
a4ffc152 | 427 | struct dm_verity *v = io->v; |
e42c3f91 | 428 | struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_bio_data_size); |
a4ffc152 MP |
429 | |
430 | bio->bi_end_io = io->orig_bi_end_io; | |
4246a0b6 | 431 | bio->bi_error = error; |
a4ffc152 | 432 | |
4246a0b6 | 433 | bio_endio(bio); |
a4ffc152 MP |
434 | } |
435 | ||
436 | static void verity_work(struct work_struct *w) | |
437 | { | |
438 | struct dm_verity_io *io = container_of(w, struct dm_verity_io, work); | |
439 | ||
440 | verity_finish_io(io, verity_verify_io(io)); | |
441 | } | |
442 | ||
4246a0b6 | 443 | static void verity_end_io(struct bio *bio) |
a4ffc152 MP |
444 | { |
445 | struct dm_verity_io *io = bio->bi_private; | |
446 | ||
4246a0b6 CH |
447 | if (bio->bi_error) { |
448 | verity_finish_io(io, bio->bi_error); | |
a4ffc152 MP |
449 | return; |
450 | } | |
451 | ||
452 | INIT_WORK(&io->work, verity_work); | |
453 | queue_work(io->v->verify_wq, &io->work); | |
454 | } | |
455 | ||
456 | /* | |
457 | * Prefetch buffers for the specified io. | |
458 | * The root buffer is not prefetched, it is assumed that it will be cached | |
459 | * all the time. | |
460 | */ | |
3b6b7813 | 461 | static void verity_prefetch_io(struct work_struct *work) |
a4ffc152 | 462 | { |
3b6b7813 MP |
463 | struct dm_verity_prefetch_work *pw = |
464 | container_of(work, struct dm_verity_prefetch_work, work); | |
465 | struct dm_verity *v = pw->v; | |
a4ffc152 MP |
466 | int i; |
467 | ||
468 | for (i = v->levels - 2; i >= 0; i--) { | |
469 | sector_t hash_block_start; | |
470 | sector_t hash_block_end; | |
3b6b7813 MP |
471 | verity_hash_at_level(v, pw->block, i, &hash_block_start, NULL); |
472 | verity_hash_at_level(v, pw->block + pw->n_blocks - 1, i, &hash_block_end, NULL); | |
a4ffc152 | 473 | if (!i) { |
fe5fe906 | 474 | unsigned cluster = ACCESS_ONCE(dm_verity_prefetch_cluster); |
a4ffc152 MP |
475 | |
476 | cluster >>= v->data_dev_block_bits; | |
477 | if (unlikely(!cluster)) | |
478 | goto no_prefetch_cluster; | |
479 | ||
480 | if (unlikely(cluster & (cluster - 1))) | |
553d8fe0 | 481 | cluster = 1 << __fls(cluster); |
a4ffc152 MP |
482 | |
483 | hash_block_start &= ~(sector_t)(cluster - 1); | |
484 | hash_block_end |= cluster - 1; | |
485 | if (unlikely(hash_block_end >= v->hash_blocks)) | |
486 | hash_block_end = v->hash_blocks - 1; | |
487 | } | |
488 | no_prefetch_cluster: | |
489 | dm_bufio_prefetch(v->bufio, hash_block_start, | |
490 | hash_block_end - hash_block_start + 1); | |
491 | } | |
3b6b7813 MP |
492 | |
493 | kfree(pw); | |
494 | } | |
495 | ||
496 | static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io) | |
497 | { | |
498 | struct dm_verity_prefetch_work *pw; | |
499 | ||
500 | pw = kmalloc(sizeof(struct dm_verity_prefetch_work), | |
501 | GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); | |
502 | ||
503 | if (!pw) | |
504 | return; | |
505 | ||
506 | INIT_WORK(&pw->work, verity_prefetch_io); | |
507 | pw->v = v; | |
508 | pw->block = io->block; | |
509 | pw->n_blocks = io->n_blocks; | |
510 | queue_work(v->verify_wq, &pw->work); | |
a4ffc152 MP |
511 | } |
512 | ||
513 | /* | |
514 | * Bio map function. It allocates dm_verity_io structure and bio vector and | |
515 | * fills them. Then it issues prefetches and the I/O. | |
516 | */ | |
7de3ee57 | 517 | static int verity_map(struct dm_target *ti, struct bio *bio) |
a4ffc152 MP |
518 | { |
519 | struct dm_verity *v = ti->private; | |
520 | struct dm_verity_io *io; | |
521 | ||
522 | bio->bi_bdev = v->data_dev->bdev; | |
4f024f37 | 523 | bio->bi_iter.bi_sector = verity_map_sector(v, bio->bi_iter.bi_sector); |
a4ffc152 | 524 | |
4f024f37 | 525 | if (((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) & |
a4ffc152 MP |
526 | ((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) { |
527 | DMERR_LIMIT("unaligned io"); | |
528 | return -EIO; | |
529 | } | |
530 | ||
f73a1c7d | 531 | if (bio_end_sector(bio) >> |
a4ffc152 MP |
532 | (v->data_dev_block_bits - SECTOR_SHIFT) > v->data_blocks) { |
533 | DMERR_LIMIT("io out of range"); | |
534 | return -EIO; | |
535 | } | |
536 | ||
537 | if (bio_data_dir(bio) == WRITE) | |
538 | return -EIO; | |
539 | ||
e42c3f91 | 540 | io = dm_per_bio_data(bio, ti->per_bio_data_size); |
a4ffc152 | 541 | io->v = v; |
a4ffc152 | 542 | io->orig_bi_end_io = bio->bi_end_io; |
4f024f37 KO |
543 | io->block = bio->bi_iter.bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT); |
544 | io->n_blocks = bio->bi_iter.bi_size >> v->data_dev_block_bits; | |
a4ffc152 MP |
545 | |
546 | bio->bi_end_io = verity_end_io; | |
547 | bio->bi_private = io; | |
003b5c57 | 548 | io->iter = bio->bi_iter; |
a4ffc152 | 549 | |
3b6b7813 | 550 | verity_submit_prefetch(v, io); |
a4ffc152 MP |
551 | |
552 | generic_make_request(bio); | |
553 | ||
554 | return DM_MAPIO_SUBMITTED; | |
555 | } | |
556 | ||
557 | /* | |
558 | * Status: V (valid) or C (corruption found) | |
559 | */ | |
fd7c092e MP |
560 | static void verity_status(struct dm_target *ti, status_type_t type, |
561 | unsigned status_flags, char *result, unsigned maxlen) | |
a4ffc152 MP |
562 | { |
563 | struct dm_verity *v = ti->private; | |
564 | unsigned sz = 0; | |
565 | unsigned x; | |
566 | ||
567 | switch (type) { | |
568 | case STATUSTYPE_INFO: | |
569 | DMEMIT("%c", v->hash_failed ? 'C' : 'V'); | |
570 | break; | |
571 | case STATUSTYPE_TABLE: | |
572 | DMEMIT("%u %s %s %u %u %llu %llu %s ", | |
573 | v->version, | |
574 | v->data_dev->name, | |
575 | v->hash_dev->name, | |
576 | 1 << v->data_dev_block_bits, | |
577 | 1 << v->hash_dev_block_bits, | |
578 | (unsigned long long)v->data_blocks, | |
579 | (unsigned long long)v->hash_start, | |
580 | v->alg_name | |
581 | ); | |
582 | for (x = 0; x < v->digest_size; x++) | |
583 | DMEMIT("%02x", v->root_digest[x]); | |
584 | DMEMIT(" "); | |
585 | if (!v->salt_size) | |
586 | DMEMIT("-"); | |
587 | else | |
588 | for (x = 0; x < v->salt_size; x++) | |
589 | DMEMIT("%02x", v->salt[x]); | |
65ff5b7d ST |
590 | if (v->mode != DM_VERITY_MODE_EIO) { |
591 | DMEMIT(" 1 "); | |
592 | switch (v->mode) { | |
593 | case DM_VERITY_MODE_LOGGING: | |
594 | DMEMIT(DM_VERITY_OPT_LOGGING); | |
595 | break; | |
596 | case DM_VERITY_MODE_RESTART: | |
597 | DMEMIT(DM_VERITY_OPT_RESTART); | |
598 | break; | |
599 | default: | |
600 | BUG(); | |
601 | } | |
602 | } | |
a4ffc152 MP |
603 | break; |
604 | } | |
a4ffc152 MP |
605 | } |
606 | ||
e56f81e0 CH |
607 | static int verity_prepare_ioctl(struct dm_target *ti, |
608 | struct block_device **bdev, fmode_t *mode) | |
a4ffc152 MP |
609 | { |
610 | struct dm_verity *v = ti->private; | |
e56f81e0 CH |
611 | |
612 | *bdev = v->data_dev->bdev; | |
a4ffc152 MP |
613 | |
614 | if (v->data_start || | |
615 | ti->len != i_size_read(v->data_dev->bdev->bd_inode) >> SECTOR_SHIFT) | |
e56f81e0 CH |
616 | return 1; |
617 | return 0; | |
a4ffc152 MP |
618 | } |
619 | ||
a4ffc152 MP |
620 | static int verity_iterate_devices(struct dm_target *ti, |
621 | iterate_devices_callout_fn fn, void *data) | |
622 | { | |
623 | struct dm_verity *v = ti->private; | |
624 | ||
625 | return fn(ti, v->data_dev, v->data_start, ti->len, data); | |
626 | } | |
627 | ||
628 | static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits) | |
629 | { | |
630 | struct dm_verity *v = ti->private; | |
631 | ||
632 | if (limits->logical_block_size < 1 << v->data_dev_block_bits) | |
633 | limits->logical_block_size = 1 << v->data_dev_block_bits; | |
634 | ||
635 | if (limits->physical_block_size < 1 << v->data_dev_block_bits) | |
636 | limits->physical_block_size = 1 << v->data_dev_block_bits; | |
637 | ||
638 | blk_limits_io_min(limits, limits->logical_block_size); | |
639 | } | |
640 | ||
641 | static void verity_dtr(struct dm_target *ti) | |
642 | { | |
643 | struct dm_verity *v = ti->private; | |
644 | ||
645 | if (v->verify_wq) | |
646 | destroy_workqueue(v->verify_wq); | |
647 | ||
a4ffc152 MP |
648 | if (v->bufio) |
649 | dm_bufio_client_destroy(v->bufio); | |
650 | ||
651 | kfree(v->salt); | |
652 | kfree(v->root_digest); | |
653 | ||
654 | if (v->tfm) | |
655 | crypto_free_shash(v->tfm); | |
656 | ||
657 | kfree(v->alg_name); | |
658 | ||
659 | if (v->hash_dev) | |
660 | dm_put_device(ti, v->hash_dev); | |
661 | ||
662 | if (v->data_dev) | |
663 | dm_put_device(ti, v->data_dev); | |
664 | ||
665 | kfree(v); | |
666 | } | |
667 | ||
753c1fd0 ST |
668 | static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v) |
669 | { | |
670 | int r; | |
671 | unsigned argc; | |
672 | struct dm_target *ti = v->ti; | |
673 | const char *arg_name; | |
674 | ||
675 | static struct dm_arg _args[] = { | |
676 | {0, DM_VERITY_OPTS_MAX, "Invalid number of feature args"}, | |
677 | }; | |
678 | ||
679 | r = dm_read_arg_group(_args, as, &argc, &ti->error); | |
680 | if (r) | |
681 | return -EINVAL; | |
682 | ||
683 | if (!argc) | |
684 | return 0; | |
685 | ||
686 | do { | |
687 | arg_name = dm_shift_arg(as); | |
688 | argc--; | |
689 | ||
690 | if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING)) { | |
691 | v->mode = DM_VERITY_MODE_LOGGING; | |
692 | continue; | |
693 | ||
694 | } else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART)) { | |
695 | v->mode = DM_VERITY_MODE_RESTART; | |
696 | continue; | |
697 | } | |
698 | ||
699 | ti->error = "Unrecognized verity feature request"; | |
700 | return -EINVAL; | |
701 | } while (argc && !r); | |
702 | ||
703 | return r; | |
704 | } | |
705 | ||
a4ffc152 MP |
706 | /* |
707 | * Target parameters: | |
708 | * <version> The current format is version 1. | |
709 | * Vsn 0 is compatible with original Chromium OS releases. | |
710 | * <data device> | |
711 | * <hash device> | |
712 | * <data block size> | |
713 | * <hash block size> | |
714 | * <the number of data blocks> | |
715 | * <hash start block> | |
716 | * <algorithm> | |
717 | * <digest> | |
718 | * <salt> Hex string or "-" if no salt. | |
719 | */ | |
720 | static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) | |
721 | { | |
722 | struct dm_verity *v; | |
65ff5b7d | 723 | struct dm_arg_set as; |
753c1fd0 | 724 | unsigned int num; |
a4ffc152 MP |
725 | unsigned long long num_ll; |
726 | int r; | |
727 | int i; | |
728 | sector_t hash_position; | |
729 | char dummy; | |
730 | ||
731 | v = kzalloc(sizeof(struct dm_verity), GFP_KERNEL); | |
732 | if (!v) { | |
733 | ti->error = "Cannot allocate verity structure"; | |
734 | return -ENOMEM; | |
735 | } | |
736 | ti->private = v; | |
737 | v->ti = ti; | |
738 | ||
739 | if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) { | |
740 | ti->error = "Device must be readonly"; | |
741 | r = -EINVAL; | |
742 | goto bad; | |
743 | } | |
744 | ||
65ff5b7d ST |
745 | if (argc < 10) { |
746 | ti->error = "Not enough arguments"; | |
a4ffc152 MP |
747 | r = -EINVAL; |
748 | goto bad; | |
749 | } | |
750 | ||
5d8be843 MP |
751 | if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 || |
752 | num > 1) { | |
a4ffc152 MP |
753 | ti->error = "Invalid version"; |
754 | r = -EINVAL; | |
755 | goto bad; | |
756 | } | |
757 | v->version = num; | |
758 | ||
759 | r = dm_get_device(ti, argv[1], FMODE_READ, &v->data_dev); | |
760 | if (r) { | |
761 | ti->error = "Data device lookup failed"; | |
762 | goto bad; | |
763 | } | |
764 | ||
765 | r = dm_get_device(ti, argv[2], FMODE_READ, &v->hash_dev); | |
766 | if (r) { | |
767 | ti->error = "Data device lookup failed"; | |
768 | goto bad; | |
769 | } | |
770 | ||
771 | if (sscanf(argv[3], "%u%c", &num, &dummy) != 1 || | |
772 | !num || (num & (num - 1)) || | |
773 | num < bdev_logical_block_size(v->data_dev->bdev) || | |
774 | num > PAGE_SIZE) { | |
775 | ti->error = "Invalid data device block size"; | |
776 | r = -EINVAL; | |
777 | goto bad; | |
778 | } | |
553d8fe0 | 779 | v->data_dev_block_bits = __ffs(num); |
a4ffc152 MP |
780 | |
781 | if (sscanf(argv[4], "%u%c", &num, &dummy) != 1 || | |
782 | !num || (num & (num - 1)) || | |
783 | num < bdev_logical_block_size(v->hash_dev->bdev) || | |
784 | num > INT_MAX) { | |
785 | ti->error = "Invalid hash device block size"; | |
786 | r = -EINVAL; | |
787 | goto bad; | |
788 | } | |
553d8fe0 | 789 | v->hash_dev_block_bits = __ffs(num); |
a4ffc152 MP |
790 | |
791 | if (sscanf(argv[5], "%llu%c", &num_ll, &dummy) != 1 || | |
1d55f6bc MP |
792 | (sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT)) |
793 | >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll) { | |
a4ffc152 MP |
794 | ti->error = "Invalid data blocks"; |
795 | r = -EINVAL; | |
796 | goto bad; | |
797 | } | |
798 | v->data_blocks = num_ll; | |
799 | ||
800 | if (ti->len > (v->data_blocks << (v->data_dev_block_bits - SECTOR_SHIFT))) { | |
801 | ti->error = "Data device is too small"; | |
802 | r = -EINVAL; | |
803 | goto bad; | |
804 | } | |
805 | ||
806 | if (sscanf(argv[6], "%llu%c", &num_ll, &dummy) != 1 || | |
1d55f6bc MP |
807 | (sector_t)(num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT)) |
808 | >> (v->hash_dev_block_bits - SECTOR_SHIFT) != num_ll) { | |
a4ffc152 MP |
809 | ti->error = "Invalid hash start"; |
810 | r = -EINVAL; | |
811 | goto bad; | |
812 | } | |
813 | v->hash_start = num_ll; | |
814 | ||
815 | v->alg_name = kstrdup(argv[7], GFP_KERNEL); | |
816 | if (!v->alg_name) { | |
817 | ti->error = "Cannot allocate algorithm name"; | |
818 | r = -ENOMEM; | |
819 | goto bad; | |
820 | } | |
821 | ||
822 | v->tfm = crypto_alloc_shash(v->alg_name, 0, 0); | |
823 | if (IS_ERR(v->tfm)) { | |
824 | ti->error = "Cannot initialize hash function"; | |
825 | r = PTR_ERR(v->tfm); | |
826 | v->tfm = NULL; | |
827 | goto bad; | |
828 | } | |
829 | v->digest_size = crypto_shash_digestsize(v->tfm); | |
830 | if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) { | |
831 | ti->error = "Digest size too big"; | |
832 | r = -EINVAL; | |
833 | goto bad; | |
834 | } | |
835 | v->shash_descsize = | |
836 | sizeof(struct shash_desc) + crypto_shash_descsize(v->tfm); | |
837 | ||
838 | v->root_digest = kmalloc(v->digest_size, GFP_KERNEL); | |
839 | if (!v->root_digest) { | |
840 | ti->error = "Cannot allocate root digest"; | |
841 | r = -ENOMEM; | |
842 | goto bad; | |
843 | } | |
844 | if (strlen(argv[8]) != v->digest_size * 2 || | |
845 | hex2bin(v->root_digest, argv[8], v->digest_size)) { | |
846 | ti->error = "Invalid root digest"; | |
847 | r = -EINVAL; | |
848 | goto bad; | |
849 | } | |
850 | ||
851 | if (strcmp(argv[9], "-")) { | |
852 | v->salt_size = strlen(argv[9]) / 2; | |
853 | v->salt = kmalloc(v->salt_size, GFP_KERNEL); | |
854 | if (!v->salt) { | |
855 | ti->error = "Cannot allocate salt"; | |
856 | r = -ENOMEM; | |
857 | goto bad; | |
858 | } | |
859 | if (strlen(argv[9]) != v->salt_size * 2 || | |
860 | hex2bin(v->salt, argv[9], v->salt_size)) { | |
861 | ti->error = "Invalid salt"; | |
862 | r = -EINVAL; | |
863 | goto bad; | |
864 | } | |
865 | } | |
866 | ||
65ff5b7d ST |
867 | argv += 10; |
868 | argc -= 10; | |
869 | ||
870 | /* Optional parameters */ | |
871 | if (argc) { | |
872 | as.argc = argc; | |
873 | as.argv = argv; | |
874 | ||
753c1fd0 ST |
875 | r = verity_parse_opt_args(&as, v); |
876 | if (r < 0) | |
65ff5b7d | 877 | goto bad; |
65ff5b7d ST |
878 | } |
879 | ||
a4ffc152 | 880 | v->hash_per_block_bits = |
553d8fe0 | 881 | __fls((1 << v->hash_dev_block_bits) / v->digest_size); |
a4ffc152 MP |
882 | |
883 | v->levels = 0; | |
884 | if (v->data_blocks) | |
885 | while (v->hash_per_block_bits * v->levels < 64 && | |
886 | (unsigned long long)(v->data_blocks - 1) >> | |
887 | (v->hash_per_block_bits * v->levels)) | |
888 | v->levels++; | |
889 | ||
890 | if (v->levels > DM_VERITY_MAX_LEVELS) { | |
891 | ti->error = "Too many tree levels"; | |
892 | r = -E2BIG; | |
893 | goto bad; | |
894 | } | |
895 | ||
896 | hash_position = v->hash_start; | |
897 | for (i = v->levels - 1; i >= 0; i--) { | |
898 | sector_t s; | |
899 | v->hash_level_block[i] = hash_position; | |
b1bf2de0 MP |
900 | s = (v->data_blocks + ((sector_t)1 << ((i + 1) * v->hash_per_block_bits)) - 1) |
901 | >> ((i + 1) * v->hash_per_block_bits); | |
a4ffc152 MP |
902 | if (hash_position + s < hash_position) { |
903 | ti->error = "Hash device offset overflow"; | |
904 | r = -E2BIG; | |
905 | goto bad; | |
906 | } | |
907 | hash_position += s; | |
908 | } | |
909 | v->hash_blocks = hash_position; | |
910 | ||
911 | v->bufio = dm_bufio_client_create(v->hash_dev->bdev, | |
912 | 1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux), | |
913 | dm_bufio_alloc_callback, NULL); | |
914 | if (IS_ERR(v->bufio)) { | |
915 | ti->error = "Cannot initialize dm-bufio"; | |
916 | r = PTR_ERR(v->bufio); | |
917 | v->bufio = NULL; | |
918 | goto bad; | |
919 | } | |
920 | ||
921 | if (dm_bufio_get_device_size(v->bufio) < v->hash_blocks) { | |
922 | ti->error = "Hash device is too small"; | |
923 | r = -E2BIG; | |
924 | goto bad; | |
925 | } | |
926 | ||
e42c3f91 | 927 | ti->per_bio_data_size = roundup(sizeof(struct dm_verity_io) + v->shash_descsize + v->digest_size * 2, __alignof__(struct dm_verity_io)); |
a4ffc152 | 928 | |
a4ffc152 MP |
929 | /* WQ_UNBOUND greatly improves performance when running on ramdisk */ |
930 | v->verify_wq = alloc_workqueue("kverityd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND, num_online_cpus()); | |
931 | if (!v->verify_wq) { | |
932 | ti->error = "Cannot allocate workqueue"; | |
933 | r = -ENOMEM; | |
934 | goto bad; | |
935 | } | |
936 | ||
937 | return 0; | |
938 | ||
939 | bad: | |
940 | verity_dtr(ti); | |
941 | ||
942 | return r; | |
943 | } | |
944 | ||
945 | static struct target_type verity_target = { | |
946 | .name = "verity", | |
3b6b7813 | 947 | .version = {1, 2, 0}, |
a4ffc152 MP |
948 | .module = THIS_MODULE, |
949 | .ctr = verity_ctr, | |
950 | .dtr = verity_dtr, | |
951 | .map = verity_map, | |
952 | .status = verity_status, | |
e56f81e0 | 953 | .prepare_ioctl = verity_prepare_ioctl, |
a4ffc152 MP |
954 | .iterate_devices = verity_iterate_devices, |
955 | .io_hints = verity_io_hints, | |
956 | }; | |
957 | ||
958 | static int __init dm_verity_init(void) | |
959 | { | |
960 | int r; | |
961 | ||
962 | r = dm_register_target(&verity_target); | |
963 | if (r < 0) | |
964 | DMERR("register failed %d", r); | |
965 | ||
966 | return r; | |
967 | } | |
968 | ||
969 | static void __exit dm_verity_exit(void) | |
970 | { | |
971 | dm_unregister_target(&verity_target); | |
972 | } | |
973 | ||
974 | module_init(dm_verity_init); | |
975 | module_exit(dm_verity_exit); | |
976 | ||
977 | MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>"); | |
978 | MODULE_AUTHOR("Mandeep Baines <msb@chromium.org>"); | |
979 | MODULE_AUTHOR("Will Drewry <wad@chromium.org>"); | |
980 | MODULE_DESCRIPTION(DM_NAME " target for transparent disk integrity checking"); | |
981 | MODULE_LICENSE("GPL"); |