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 | ||
17 | #include "dm-bufio.h" | |
18 | ||
19 | #include <linux/module.h> | |
20 | #include <linux/device-mapper.h> | |
65ff5b7d | 21 | #include <linux/reboot.h> |
a4ffc152 MP |
22 | #include <crypto/hash.h> |
23 | ||
24 | #define DM_MSG_PREFIX "verity" | |
25 | ||
65ff5b7d ST |
26 | #define DM_VERITY_ENV_LENGTH 42 |
27 | #define DM_VERITY_ENV_VAR_NAME "DM_VERITY_ERR_BLOCK_NR" | |
28 | ||
a4ffc152 MP |
29 | #define DM_VERITY_IO_VEC_INLINE 16 |
30 | #define DM_VERITY_MEMPOOL_SIZE 4 | |
31 | #define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144 | |
32 | ||
33 | #define DM_VERITY_MAX_LEVELS 63 | |
65ff5b7d ST |
34 | #define DM_VERITY_MAX_CORRUPTED_ERRS 100 |
35 | ||
36 | #define DM_VERITY_OPT_LOGGING "ignore_corruption" | |
37 | #define DM_VERITY_OPT_RESTART "restart_on_corruption" | |
a4ffc152 MP |
38 | |
39 | static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE; | |
40 | ||
41 | module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR); | |
42 | ||
65ff5b7d ST |
43 | enum verity_mode { |
44 | DM_VERITY_MODE_EIO, | |
45 | DM_VERITY_MODE_LOGGING, | |
46 | DM_VERITY_MODE_RESTART | |
47 | }; | |
48 | ||
49 | enum verity_block_type { | |
50 | DM_VERITY_BLOCK_TYPE_DATA, | |
51 | DM_VERITY_BLOCK_TYPE_METADATA | |
52 | }; | |
53 | ||
a4ffc152 MP |
54 | struct dm_verity { |
55 | struct dm_dev *data_dev; | |
56 | struct dm_dev *hash_dev; | |
57 | struct dm_target *ti; | |
58 | struct dm_bufio_client *bufio; | |
59 | char *alg_name; | |
60 | struct crypto_shash *tfm; | |
61 | u8 *root_digest; /* digest of the root block */ | |
62 | u8 *salt; /* salt: its size is salt_size */ | |
63 | unsigned salt_size; | |
64 | sector_t data_start; /* data offset in 512-byte sectors */ | |
65 | sector_t hash_start; /* hash start in blocks */ | |
66 | sector_t data_blocks; /* the number of data blocks */ | |
67 | sector_t hash_blocks; /* the number of hash blocks */ | |
68 | unsigned char data_dev_block_bits; /* log2(data blocksize) */ | |
69 | unsigned char hash_dev_block_bits; /* log2(hash blocksize) */ | |
70 | unsigned char hash_per_block_bits; /* log2(hashes in hash block) */ | |
71 | unsigned char levels; /* the number of tree levels */ | |
72 | unsigned char version; | |
73 | unsigned digest_size; /* digest size for the current hash algorithm */ | |
74 | unsigned shash_descsize;/* the size of temporary space for crypto */ | |
75 | int hash_failed; /* set to 1 if hash of any block failed */ | |
65ff5b7d ST |
76 | enum verity_mode mode; /* mode for handling verification errors */ |
77 | unsigned corrupted_errs;/* Number of errors for corrupted blocks */ | |
a4ffc152 | 78 | |
a4ffc152 MP |
79 | mempool_t *vec_mempool; /* mempool of bio vector */ |
80 | ||
81 | struct workqueue_struct *verify_wq; | |
82 | ||
83 | /* starting blocks for each tree level. 0 is the lowest level. */ | |
84 | sector_t hash_level_block[DM_VERITY_MAX_LEVELS]; | |
85 | }; | |
86 | ||
87 | struct dm_verity_io { | |
88 | struct dm_verity *v; | |
a4ffc152 MP |
89 | |
90 | /* original values of bio->bi_end_io and bio->bi_private */ | |
91 | bio_end_io_t *orig_bi_end_io; | |
92 | void *orig_bi_private; | |
93 | ||
94 | sector_t block; | |
95 | unsigned n_blocks; | |
96 | ||
003b5c57 | 97 | struct bvec_iter iter; |
a4ffc152 MP |
98 | |
99 | struct work_struct work; | |
100 | ||
a4ffc152 MP |
101 | /* |
102 | * Three variably-size fields follow this struct: | |
103 | * | |
104 | * u8 hash_desc[v->shash_descsize]; | |
105 | * u8 real_digest[v->digest_size]; | |
106 | * u8 want_digest[v->digest_size]; | |
107 | * | |
108 | * To access them use: io_hash_desc(), io_real_digest() and io_want_digest(). | |
109 | */ | |
110 | }; | |
111 | ||
3b6b7813 MP |
112 | struct dm_verity_prefetch_work { |
113 | struct work_struct work; | |
114 | struct dm_verity *v; | |
115 | sector_t block; | |
116 | unsigned n_blocks; | |
117 | }; | |
118 | ||
a4ffc152 MP |
119 | static struct shash_desc *io_hash_desc(struct dm_verity *v, struct dm_verity_io *io) |
120 | { | |
121 | return (struct shash_desc *)(io + 1); | |
122 | } | |
123 | ||
124 | static u8 *io_real_digest(struct dm_verity *v, struct dm_verity_io *io) | |
125 | { | |
126 | return (u8 *)(io + 1) + v->shash_descsize; | |
127 | } | |
128 | ||
129 | static u8 *io_want_digest(struct dm_verity *v, struct dm_verity_io *io) | |
130 | { | |
131 | return (u8 *)(io + 1) + v->shash_descsize + v->digest_size; | |
132 | } | |
133 | ||
134 | /* | |
135 | * Auxiliary structure appended to each dm-bufio buffer. If the value | |
136 | * hash_verified is nonzero, hash of the block has been verified. | |
137 | * | |
138 | * The variable hash_verified is set to 0 when allocating the buffer, then | |
139 | * it can be changed to 1 and it is never reset to 0 again. | |
140 | * | |
141 | * There is no lock around this value, a race condition can at worst cause | |
142 | * that multiple processes verify the hash of the same buffer simultaneously | |
143 | * and write 1 to hash_verified simultaneously. | |
144 | * This condition is harmless, so we don't need locking. | |
145 | */ | |
146 | struct buffer_aux { | |
147 | int hash_verified; | |
148 | }; | |
149 | ||
150 | /* | |
151 | * Initialize struct buffer_aux for a freshly created buffer. | |
152 | */ | |
153 | static void dm_bufio_alloc_callback(struct dm_buffer *buf) | |
154 | { | |
155 | struct buffer_aux *aux = dm_bufio_get_aux_data(buf); | |
156 | ||
157 | aux->hash_verified = 0; | |
158 | } | |
159 | ||
160 | /* | |
161 | * Translate input sector number to the sector number on the target device. | |
162 | */ | |
163 | static sector_t verity_map_sector(struct dm_verity *v, sector_t bi_sector) | |
164 | { | |
165 | return v->data_start + dm_target_offset(v->ti, bi_sector); | |
166 | } | |
167 | ||
168 | /* | |
169 | * Return hash position of a specified block at a specified tree level | |
170 | * (0 is the lowest level). | |
171 | * The lowest "hash_per_block_bits"-bits of the result denote hash position | |
172 | * inside a hash block. The remaining bits denote location of the hash block. | |
173 | */ | |
174 | static sector_t verity_position_at_level(struct dm_verity *v, sector_t block, | |
175 | int level) | |
176 | { | |
177 | return block >> (level * v->hash_per_block_bits); | |
178 | } | |
179 | ||
180 | static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level, | |
181 | sector_t *hash_block, unsigned *offset) | |
182 | { | |
183 | sector_t position = verity_position_at_level(v, block, level); | |
184 | unsigned idx; | |
185 | ||
186 | *hash_block = v->hash_level_block[level] + (position >> v->hash_per_block_bits); | |
187 | ||
188 | if (!offset) | |
189 | return; | |
190 | ||
191 | idx = position & ((1 << v->hash_per_block_bits) - 1); | |
192 | if (!v->version) | |
193 | *offset = idx * v->digest_size; | |
194 | else | |
195 | *offset = idx << (v->hash_dev_block_bits - v->hash_per_block_bits); | |
196 | } | |
197 | ||
65ff5b7d ST |
198 | /* |
199 | * Handle verification errors. | |
200 | */ | |
201 | static int verity_handle_err(struct dm_verity *v, enum verity_block_type type, | |
202 | unsigned long long block) | |
203 | { | |
204 | char verity_env[DM_VERITY_ENV_LENGTH]; | |
205 | char *envp[] = { verity_env, NULL }; | |
206 | const char *type_str = ""; | |
207 | struct mapped_device *md = dm_table_get_md(v->ti->table); | |
208 | ||
209 | /* Corruption should be visible in device status in all modes */ | |
210 | v->hash_failed = 1; | |
211 | ||
212 | if (v->corrupted_errs >= DM_VERITY_MAX_CORRUPTED_ERRS) | |
213 | goto out; | |
214 | ||
215 | v->corrupted_errs++; | |
216 | ||
217 | switch (type) { | |
218 | case DM_VERITY_BLOCK_TYPE_DATA: | |
219 | type_str = "data"; | |
220 | break; | |
221 | case DM_VERITY_BLOCK_TYPE_METADATA: | |
222 | type_str = "metadata"; | |
223 | break; | |
224 | default: | |
225 | BUG(); | |
226 | } | |
227 | ||
228 | DMERR("%s: %s block %llu is corrupted", v->data_dev->name, type_str, | |
229 | block); | |
230 | ||
231 | if (v->corrupted_errs == DM_VERITY_MAX_CORRUPTED_ERRS) | |
232 | DMERR("%s: reached maximum errors", v->data_dev->name); | |
233 | ||
234 | snprintf(verity_env, DM_VERITY_ENV_LENGTH, "%s=%d,%llu", | |
235 | DM_VERITY_ENV_VAR_NAME, type, block); | |
236 | ||
237 | kobject_uevent_env(&disk_to_dev(dm_disk(md))->kobj, KOBJ_CHANGE, envp); | |
238 | ||
239 | out: | |
240 | if (v->mode == DM_VERITY_MODE_LOGGING) | |
241 | return 0; | |
242 | ||
243 | if (v->mode == DM_VERITY_MODE_RESTART) | |
244 | kernel_restart("dm-verity device corrupted"); | |
245 | ||
246 | return 1; | |
247 | } | |
248 | ||
a4ffc152 MP |
249 | /* |
250 | * Verify hash of a metadata block pertaining to the specified data block | |
251 | * ("block" argument) at a specified level ("level" argument). | |
252 | * | |
253 | * On successful return, io_want_digest(v, io) contains the hash value for | |
254 | * a lower tree level or for the data block (if we're at the lowest leve). | |
255 | * | |
256 | * If "skip_unverified" is true, unverified buffer is skipped and 1 is returned. | |
257 | * If "skip_unverified" is false, unverified buffer is hashed and verified | |
258 | * against current value of io_want_digest(v, io). | |
259 | */ | |
260 | static int verity_verify_level(struct dm_verity_io *io, sector_t block, | |
261 | int level, bool skip_unverified) | |
262 | { | |
263 | struct dm_verity *v = io->v; | |
264 | struct dm_buffer *buf; | |
265 | struct buffer_aux *aux; | |
266 | u8 *data; | |
267 | int r; | |
268 | sector_t hash_block; | |
269 | unsigned offset; | |
270 | ||
271 | verity_hash_at_level(v, block, level, &hash_block, &offset); | |
272 | ||
273 | data = dm_bufio_read(v->bufio, hash_block, &buf); | |
274 | if (unlikely(IS_ERR(data))) | |
275 | return PTR_ERR(data); | |
276 | ||
277 | aux = dm_bufio_get_aux_data(buf); | |
278 | ||
279 | if (!aux->hash_verified) { | |
280 | struct shash_desc *desc; | |
281 | u8 *result; | |
282 | ||
283 | if (skip_unverified) { | |
284 | r = 1; | |
285 | goto release_ret_r; | |
286 | } | |
287 | ||
288 | desc = io_hash_desc(v, io); | |
289 | desc->tfm = v->tfm; | |
290 | desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; | |
291 | r = crypto_shash_init(desc); | |
292 | if (r < 0) { | |
293 | DMERR("crypto_shash_init failed: %d", r); | |
294 | goto release_ret_r; | |
295 | } | |
296 | ||
297 | if (likely(v->version >= 1)) { | |
298 | r = crypto_shash_update(desc, v->salt, v->salt_size); | |
299 | if (r < 0) { | |
300 | DMERR("crypto_shash_update failed: %d", r); | |
301 | goto release_ret_r; | |
302 | } | |
303 | } | |
304 | ||
305 | r = crypto_shash_update(desc, data, 1 << v->hash_dev_block_bits); | |
306 | if (r < 0) { | |
307 | DMERR("crypto_shash_update failed: %d", r); | |
308 | goto release_ret_r; | |
309 | } | |
310 | ||
311 | if (!v->version) { | |
312 | r = crypto_shash_update(desc, v->salt, v->salt_size); | |
313 | if (r < 0) { | |
314 | DMERR("crypto_shash_update failed: %d", r); | |
315 | goto release_ret_r; | |
316 | } | |
317 | } | |
318 | ||
319 | result = io_real_digest(v, io); | |
320 | r = crypto_shash_final(desc, result); | |
321 | if (r < 0) { | |
322 | DMERR("crypto_shash_final failed: %d", r); | |
323 | goto release_ret_r; | |
324 | } | |
325 | if (unlikely(memcmp(result, io_want_digest(v, io), v->digest_size))) { | |
65ff5b7d ST |
326 | if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_METADATA, |
327 | hash_block)) { | |
328 | r = -EIO; | |
329 | goto release_ret_r; | |
330 | } | |
a4ffc152 MP |
331 | } else |
332 | aux->hash_verified = 1; | |
333 | } | |
334 | ||
335 | data += offset; | |
336 | ||
337 | memcpy(io_want_digest(v, io), data, v->digest_size); | |
338 | ||
339 | dm_bufio_release(buf); | |
340 | return 0; | |
341 | ||
342 | release_ret_r: | |
343 | dm_bufio_release(buf); | |
344 | ||
345 | return r; | |
346 | } | |
347 | ||
348 | /* | |
349 | * Verify one "dm_verity_io" structure. | |
350 | */ | |
351 | static int verity_verify_io(struct dm_verity_io *io) | |
352 | { | |
353 | struct dm_verity *v = io->v; | |
003b5c57 KO |
354 | struct bio *bio = dm_bio_from_per_bio_data(io, |
355 | v->ti->per_bio_data_size); | |
a4ffc152 MP |
356 | unsigned b; |
357 | int i; | |
a4ffc152 MP |
358 | |
359 | for (b = 0; b < io->n_blocks; b++) { | |
360 | struct shash_desc *desc; | |
361 | u8 *result; | |
362 | int r; | |
363 | unsigned todo; | |
364 | ||
365 | if (likely(v->levels)) { | |
366 | /* | |
367 | * First, we try to get the requested hash for | |
368 | * the current block. If the hash block itself is | |
369 | * verified, zero is returned. If it isn't, this | |
370 | * function returns 0 and we fall back to whole | |
371 | * chain verification. | |
372 | */ | |
373 | int r = verity_verify_level(io, io->block + b, 0, true); | |
374 | if (likely(!r)) | |
375 | goto test_block_hash; | |
376 | if (r < 0) | |
377 | return r; | |
378 | } | |
379 | ||
380 | memcpy(io_want_digest(v, io), v->root_digest, v->digest_size); | |
381 | ||
382 | for (i = v->levels - 1; i >= 0; i--) { | |
383 | int r = verity_verify_level(io, io->block + b, i, false); | |
384 | if (unlikely(r)) | |
385 | return r; | |
386 | } | |
387 | ||
388 | test_block_hash: | |
389 | desc = io_hash_desc(v, io); | |
390 | desc->tfm = v->tfm; | |
391 | desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; | |
392 | r = crypto_shash_init(desc); | |
393 | if (r < 0) { | |
394 | DMERR("crypto_shash_init failed: %d", r); | |
395 | return r; | |
396 | } | |
397 | ||
398 | if (likely(v->version >= 1)) { | |
399 | r = crypto_shash_update(desc, v->salt, v->salt_size); | |
400 | if (r < 0) { | |
401 | DMERR("crypto_shash_update failed: %d", r); | |
402 | return r; | |
403 | } | |
404 | } | |
a4ffc152 | 405 | todo = 1 << v->data_dev_block_bits; |
3a774521 | 406 | do { |
a4ffc152 | 407 | u8 *page; |
3a774521 | 408 | unsigned len; |
003b5c57 KO |
409 | struct bio_vec bv = bio_iter_iovec(bio, io->iter); |
410 | ||
411 | page = kmap_atomic(bv.bv_page); | |
3a774521 MB |
412 | len = bv.bv_len; |
413 | if (likely(len >= todo)) | |
414 | len = todo; | |
415 | r = crypto_shash_update(desc, page + bv.bv_offset, len); | |
a4ffc152 | 416 | kunmap_atomic(page); |
003b5c57 | 417 | |
a4ffc152 MP |
418 | if (r < 0) { |
419 | DMERR("crypto_shash_update failed: %d", r); | |
420 | return r; | |
421 | } | |
003b5c57 | 422 | |
3a774521 MB |
423 | bio_advance_iter(bio, &io->iter, len); |
424 | todo -= len; | |
425 | } while (todo); | |
a4ffc152 MP |
426 | |
427 | if (!v->version) { | |
428 | r = crypto_shash_update(desc, v->salt, v->salt_size); | |
429 | if (r < 0) { | |
430 | DMERR("crypto_shash_update failed: %d", r); | |
431 | return r; | |
432 | } | |
433 | } | |
434 | ||
435 | result = io_real_digest(v, io); | |
436 | r = crypto_shash_final(desc, result); | |
437 | if (r < 0) { | |
438 | DMERR("crypto_shash_final failed: %d", r); | |
439 | return r; | |
440 | } | |
441 | if (unlikely(memcmp(result, io_want_digest(v, io), v->digest_size))) { | |
65ff5b7d ST |
442 | if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA, |
443 | io->block + b)) | |
444 | return -EIO; | |
a4ffc152 MP |
445 | } |
446 | } | |
a4ffc152 MP |
447 | |
448 | return 0; | |
449 | } | |
450 | ||
451 | /* | |
452 | * End one "io" structure with a given error. | |
453 | */ | |
454 | static void verity_finish_io(struct dm_verity_io *io, int error) | |
455 | { | |
a4ffc152 | 456 | struct dm_verity *v = io->v; |
e42c3f91 | 457 | struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_bio_data_size); |
a4ffc152 MP |
458 | |
459 | bio->bi_end_io = io->orig_bi_end_io; | |
460 | bio->bi_private = io->orig_bi_private; | |
461 | ||
326e1dbb | 462 | bio_endio(bio, error); |
a4ffc152 MP |
463 | } |
464 | ||
465 | static void verity_work(struct work_struct *w) | |
466 | { | |
467 | struct dm_verity_io *io = container_of(w, struct dm_verity_io, work); | |
468 | ||
469 | verity_finish_io(io, verity_verify_io(io)); | |
470 | } | |
471 | ||
472 | static void verity_end_io(struct bio *bio, int error) | |
473 | { | |
474 | struct dm_verity_io *io = bio->bi_private; | |
475 | ||
476 | if (error) { | |
477 | verity_finish_io(io, error); | |
478 | return; | |
479 | } | |
480 | ||
481 | INIT_WORK(&io->work, verity_work); | |
482 | queue_work(io->v->verify_wq, &io->work); | |
483 | } | |
484 | ||
485 | /* | |
486 | * Prefetch buffers for the specified io. | |
487 | * The root buffer is not prefetched, it is assumed that it will be cached | |
488 | * all the time. | |
489 | */ | |
3b6b7813 | 490 | static void verity_prefetch_io(struct work_struct *work) |
a4ffc152 | 491 | { |
3b6b7813 MP |
492 | struct dm_verity_prefetch_work *pw = |
493 | container_of(work, struct dm_verity_prefetch_work, work); | |
494 | struct dm_verity *v = pw->v; | |
a4ffc152 MP |
495 | int i; |
496 | ||
497 | for (i = v->levels - 2; i >= 0; i--) { | |
498 | sector_t hash_block_start; | |
499 | sector_t hash_block_end; | |
3b6b7813 MP |
500 | verity_hash_at_level(v, pw->block, i, &hash_block_start, NULL); |
501 | verity_hash_at_level(v, pw->block + pw->n_blocks - 1, i, &hash_block_end, NULL); | |
a4ffc152 | 502 | if (!i) { |
fe5fe906 | 503 | unsigned cluster = ACCESS_ONCE(dm_verity_prefetch_cluster); |
a4ffc152 MP |
504 | |
505 | cluster >>= v->data_dev_block_bits; | |
506 | if (unlikely(!cluster)) | |
507 | goto no_prefetch_cluster; | |
508 | ||
509 | if (unlikely(cluster & (cluster - 1))) | |
553d8fe0 | 510 | cluster = 1 << __fls(cluster); |
a4ffc152 MP |
511 | |
512 | hash_block_start &= ~(sector_t)(cluster - 1); | |
513 | hash_block_end |= cluster - 1; | |
514 | if (unlikely(hash_block_end >= v->hash_blocks)) | |
515 | hash_block_end = v->hash_blocks - 1; | |
516 | } | |
517 | no_prefetch_cluster: | |
518 | dm_bufio_prefetch(v->bufio, hash_block_start, | |
519 | hash_block_end - hash_block_start + 1); | |
520 | } | |
3b6b7813 MP |
521 | |
522 | kfree(pw); | |
523 | } | |
524 | ||
525 | static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io) | |
526 | { | |
527 | struct dm_verity_prefetch_work *pw; | |
528 | ||
529 | pw = kmalloc(sizeof(struct dm_verity_prefetch_work), | |
530 | GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); | |
531 | ||
532 | if (!pw) | |
533 | return; | |
534 | ||
535 | INIT_WORK(&pw->work, verity_prefetch_io); | |
536 | pw->v = v; | |
537 | pw->block = io->block; | |
538 | pw->n_blocks = io->n_blocks; | |
539 | queue_work(v->verify_wq, &pw->work); | |
a4ffc152 MP |
540 | } |
541 | ||
542 | /* | |
543 | * Bio map function. It allocates dm_verity_io structure and bio vector and | |
544 | * fills them. Then it issues prefetches and the I/O. | |
545 | */ | |
7de3ee57 | 546 | static int verity_map(struct dm_target *ti, struct bio *bio) |
a4ffc152 MP |
547 | { |
548 | struct dm_verity *v = ti->private; | |
549 | struct dm_verity_io *io; | |
550 | ||
551 | bio->bi_bdev = v->data_dev->bdev; | |
4f024f37 | 552 | bio->bi_iter.bi_sector = verity_map_sector(v, bio->bi_iter.bi_sector); |
a4ffc152 | 553 | |
4f024f37 | 554 | if (((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) & |
a4ffc152 MP |
555 | ((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) { |
556 | DMERR_LIMIT("unaligned io"); | |
557 | return -EIO; | |
558 | } | |
559 | ||
f73a1c7d | 560 | if (bio_end_sector(bio) >> |
a4ffc152 MP |
561 | (v->data_dev_block_bits - SECTOR_SHIFT) > v->data_blocks) { |
562 | DMERR_LIMIT("io out of range"); | |
563 | return -EIO; | |
564 | } | |
565 | ||
566 | if (bio_data_dir(bio) == WRITE) | |
567 | return -EIO; | |
568 | ||
e42c3f91 | 569 | io = dm_per_bio_data(bio, ti->per_bio_data_size); |
a4ffc152 | 570 | io->v = v; |
a4ffc152 MP |
571 | io->orig_bi_end_io = bio->bi_end_io; |
572 | io->orig_bi_private = bio->bi_private; | |
4f024f37 KO |
573 | io->block = bio->bi_iter.bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT); |
574 | io->n_blocks = bio->bi_iter.bi_size >> v->data_dev_block_bits; | |
a4ffc152 MP |
575 | |
576 | bio->bi_end_io = verity_end_io; | |
577 | bio->bi_private = io; | |
003b5c57 | 578 | io->iter = bio->bi_iter; |
a4ffc152 | 579 | |
3b6b7813 | 580 | verity_submit_prefetch(v, io); |
a4ffc152 MP |
581 | |
582 | generic_make_request(bio); | |
583 | ||
584 | return DM_MAPIO_SUBMITTED; | |
585 | } | |
586 | ||
587 | /* | |
588 | * Status: V (valid) or C (corruption found) | |
589 | */ | |
fd7c092e MP |
590 | static void verity_status(struct dm_target *ti, status_type_t type, |
591 | unsigned status_flags, char *result, unsigned maxlen) | |
a4ffc152 MP |
592 | { |
593 | struct dm_verity *v = ti->private; | |
594 | unsigned sz = 0; | |
595 | unsigned x; | |
596 | ||
597 | switch (type) { | |
598 | case STATUSTYPE_INFO: | |
599 | DMEMIT("%c", v->hash_failed ? 'C' : 'V'); | |
600 | break; | |
601 | case STATUSTYPE_TABLE: | |
602 | DMEMIT("%u %s %s %u %u %llu %llu %s ", | |
603 | v->version, | |
604 | v->data_dev->name, | |
605 | v->hash_dev->name, | |
606 | 1 << v->data_dev_block_bits, | |
607 | 1 << v->hash_dev_block_bits, | |
608 | (unsigned long long)v->data_blocks, | |
609 | (unsigned long long)v->hash_start, | |
610 | v->alg_name | |
611 | ); | |
612 | for (x = 0; x < v->digest_size; x++) | |
613 | DMEMIT("%02x", v->root_digest[x]); | |
614 | DMEMIT(" "); | |
615 | if (!v->salt_size) | |
616 | DMEMIT("-"); | |
617 | else | |
618 | for (x = 0; x < v->salt_size; x++) | |
619 | DMEMIT("%02x", v->salt[x]); | |
65ff5b7d ST |
620 | if (v->mode != DM_VERITY_MODE_EIO) { |
621 | DMEMIT(" 1 "); | |
622 | switch (v->mode) { | |
623 | case DM_VERITY_MODE_LOGGING: | |
624 | DMEMIT(DM_VERITY_OPT_LOGGING); | |
625 | break; | |
626 | case DM_VERITY_MODE_RESTART: | |
627 | DMEMIT(DM_VERITY_OPT_RESTART); | |
628 | break; | |
629 | default: | |
630 | BUG(); | |
631 | } | |
632 | } | |
a4ffc152 MP |
633 | break; |
634 | } | |
a4ffc152 MP |
635 | } |
636 | ||
637 | static int verity_ioctl(struct dm_target *ti, unsigned cmd, | |
638 | unsigned long arg) | |
639 | { | |
640 | struct dm_verity *v = ti->private; | |
641 | int r = 0; | |
642 | ||
643 | if (v->data_start || | |
644 | ti->len != i_size_read(v->data_dev->bdev->bd_inode) >> SECTOR_SHIFT) | |
645 | r = scsi_verify_blk_ioctl(NULL, cmd); | |
646 | ||
647 | return r ? : __blkdev_driver_ioctl(v->data_dev->bdev, v->data_dev->mode, | |
648 | cmd, arg); | |
649 | } | |
650 | ||
651 | static int verity_merge(struct dm_target *ti, struct bvec_merge_data *bvm, | |
652 | struct bio_vec *biovec, int max_size) | |
653 | { | |
654 | struct dm_verity *v = ti->private; | |
655 | struct request_queue *q = bdev_get_queue(v->data_dev->bdev); | |
656 | ||
657 | if (!q->merge_bvec_fn) | |
658 | return max_size; | |
659 | ||
660 | bvm->bi_bdev = v->data_dev->bdev; | |
661 | bvm->bi_sector = verity_map_sector(v, bvm->bi_sector); | |
662 | ||
663 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
664 | } | |
665 | ||
666 | static int verity_iterate_devices(struct dm_target *ti, | |
667 | iterate_devices_callout_fn fn, void *data) | |
668 | { | |
669 | struct dm_verity *v = ti->private; | |
670 | ||
671 | return fn(ti, v->data_dev, v->data_start, ti->len, data); | |
672 | } | |
673 | ||
674 | static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits) | |
675 | { | |
676 | struct dm_verity *v = ti->private; | |
677 | ||
678 | if (limits->logical_block_size < 1 << v->data_dev_block_bits) | |
679 | limits->logical_block_size = 1 << v->data_dev_block_bits; | |
680 | ||
681 | if (limits->physical_block_size < 1 << v->data_dev_block_bits) | |
682 | limits->physical_block_size = 1 << v->data_dev_block_bits; | |
683 | ||
684 | blk_limits_io_min(limits, limits->logical_block_size); | |
685 | } | |
686 | ||
687 | static void verity_dtr(struct dm_target *ti) | |
688 | { | |
689 | struct dm_verity *v = ti->private; | |
690 | ||
691 | if (v->verify_wq) | |
692 | destroy_workqueue(v->verify_wq); | |
693 | ||
694 | if (v->vec_mempool) | |
695 | mempool_destroy(v->vec_mempool); | |
696 | ||
a4ffc152 MP |
697 | if (v->bufio) |
698 | dm_bufio_client_destroy(v->bufio); | |
699 | ||
700 | kfree(v->salt); | |
701 | kfree(v->root_digest); | |
702 | ||
703 | if (v->tfm) | |
704 | crypto_free_shash(v->tfm); | |
705 | ||
706 | kfree(v->alg_name); | |
707 | ||
708 | if (v->hash_dev) | |
709 | dm_put_device(ti, v->hash_dev); | |
710 | ||
711 | if (v->data_dev) | |
712 | dm_put_device(ti, v->data_dev); | |
713 | ||
714 | kfree(v); | |
715 | } | |
716 | ||
717 | /* | |
718 | * Target parameters: | |
719 | * <version> The current format is version 1. | |
720 | * Vsn 0 is compatible with original Chromium OS releases. | |
721 | * <data device> | |
722 | * <hash device> | |
723 | * <data block size> | |
724 | * <hash block size> | |
725 | * <the number of data blocks> | |
726 | * <hash start block> | |
727 | * <algorithm> | |
728 | * <digest> | |
729 | * <salt> Hex string or "-" if no salt. | |
730 | */ | |
731 | static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) | |
732 | { | |
733 | struct dm_verity *v; | |
65ff5b7d ST |
734 | struct dm_arg_set as; |
735 | const char *opt_string; | |
736 | unsigned int num, opt_params; | |
a4ffc152 MP |
737 | unsigned long long num_ll; |
738 | int r; | |
739 | int i; | |
740 | sector_t hash_position; | |
741 | char dummy; | |
742 | ||
65ff5b7d ST |
743 | static struct dm_arg _args[] = { |
744 | {0, 1, "Invalid number of feature args"}, | |
745 | }; | |
746 | ||
a4ffc152 MP |
747 | v = kzalloc(sizeof(struct dm_verity), GFP_KERNEL); |
748 | if (!v) { | |
749 | ti->error = "Cannot allocate verity structure"; | |
750 | return -ENOMEM; | |
751 | } | |
752 | ti->private = v; | |
753 | v->ti = ti; | |
754 | ||
755 | if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) { | |
756 | ti->error = "Device must be readonly"; | |
757 | r = -EINVAL; | |
758 | goto bad; | |
759 | } | |
760 | ||
65ff5b7d ST |
761 | if (argc < 10) { |
762 | ti->error = "Not enough arguments"; | |
a4ffc152 MP |
763 | r = -EINVAL; |
764 | goto bad; | |
765 | } | |
766 | ||
5d8be843 MP |
767 | if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 || |
768 | num > 1) { | |
a4ffc152 MP |
769 | ti->error = "Invalid version"; |
770 | r = -EINVAL; | |
771 | goto bad; | |
772 | } | |
773 | v->version = num; | |
774 | ||
775 | r = dm_get_device(ti, argv[1], FMODE_READ, &v->data_dev); | |
776 | if (r) { | |
777 | ti->error = "Data device lookup failed"; | |
778 | goto bad; | |
779 | } | |
780 | ||
781 | r = dm_get_device(ti, argv[2], FMODE_READ, &v->hash_dev); | |
782 | if (r) { | |
783 | ti->error = "Data device lookup failed"; | |
784 | goto bad; | |
785 | } | |
786 | ||
787 | if (sscanf(argv[3], "%u%c", &num, &dummy) != 1 || | |
788 | !num || (num & (num - 1)) || | |
789 | num < bdev_logical_block_size(v->data_dev->bdev) || | |
790 | num > PAGE_SIZE) { | |
791 | ti->error = "Invalid data device block size"; | |
792 | r = -EINVAL; | |
793 | goto bad; | |
794 | } | |
553d8fe0 | 795 | v->data_dev_block_bits = __ffs(num); |
a4ffc152 MP |
796 | |
797 | if (sscanf(argv[4], "%u%c", &num, &dummy) != 1 || | |
798 | !num || (num & (num - 1)) || | |
799 | num < bdev_logical_block_size(v->hash_dev->bdev) || | |
800 | num > INT_MAX) { | |
801 | ti->error = "Invalid hash device block size"; | |
802 | r = -EINVAL; | |
803 | goto bad; | |
804 | } | |
553d8fe0 | 805 | v->hash_dev_block_bits = __ffs(num); |
a4ffc152 MP |
806 | |
807 | if (sscanf(argv[5], "%llu%c", &num_ll, &dummy) != 1 || | |
1d55f6bc MP |
808 | (sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT)) |
809 | >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll) { | |
a4ffc152 MP |
810 | ti->error = "Invalid data blocks"; |
811 | r = -EINVAL; | |
812 | goto bad; | |
813 | } | |
814 | v->data_blocks = num_ll; | |
815 | ||
816 | if (ti->len > (v->data_blocks << (v->data_dev_block_bits - SECTOR_SHIFT))) { | |
817 | ti->error = "Data device is too small"; | |
818 | r = -EINVAL; | |
819 | goto bad; | |
820 | } | |
821 | ||
822 | if (sscanf(argv[6], "%llu%c", &num_ll, &dummy) != 1 || | |
1d55f6bc MP |
823 | (sector_t)(num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT)) |
824 | >> (v->hash_dev_block_bits - SECTOR_SHIFT) != num_ll) { | |
a4ffc152 MP |
825 | ti->error = "Invalid hash start"; |
826 | r = -EINVAL; | |
827 | goto bad; | |
828 | } | |
829 | v->hash_start = num_ll; | |
830 | ||
831 | v->alg_name = kstrdup(argv[7], GFP_KERNEL); | |
832 | if (!v->alg_name) { | |
833 | ti->error = "Cannot allocate algorithm name"; | |
834 | r = -ENOMEM; | |
835 | goto bad; | |
836 | } | |
837 | ||
838 | v->tfm = crypto_alloc_shash(v->alg_name, 0, 0); | |
839 | if (IS_ERR(v->tfm)) { | |
840 | ti->error = "Cannot initialize hash function"; | |
841 | r = PTR_ERR(v->tfm); | |
842 | v->tfm = NULL; | |
843 | goto bad; | |
844 | } | |
845 | v->digest_size = crypto_shash_digestsize(v->tfm); | |
846 | if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) { | |
847 | ti->error = "Digest size too big"; | |
848 | r = -EINVAL; | |
849 | goto bad; | |
850 | } | |
851 | v->shash_descsize = | |
852 | sizeof(struct shash_desc) + crypto_shash_descsize(v->tfm); | |
853 | ||
854 | v->root_digest = kmalloc(v->digest_size, GFP_KERNEL); | |
855 | if (!v->root_digest) { | |
856 | ti->error = "Cannot allocate root digest"; | |
857 | r = -ENOMEM; | |
858 | goto bad; | |
859 | } | |
860 | if (strlen(argv[8]) != v->digest_size * 2 || | |
861 | hex2bin(v->root_digest, argv[8], v->digest_size)) { | |
862 | ti->error = "Invalid root digest"; | |
863 | r = -EINVAL; | |
864 | goto bad; | |
865 | } | |
866 | ||
867 | if (strcmp(argv[9], "-")) { | |
868 | v->salt_size = strlen(argv[9]) / 2; | |
869 | v->salt = kmalloc(v->salt_size, GFP_KERNEL); | |
870 | if (!v->salt) { | |
871 | ti->error = "Cannot allocate salt"; | |
872 | r = -ENOMEM; | |
873 | goto bad; | |
874 | } | |
875 | if (strlen(argv[9]) != v->salt_size * 2 || | |
876 | hex2bin(v->salt, argv[9], v->salt_size)) { | |
877 | ti->error = "Invalid salt"; | |
878 | r = -EINVAL; | |
879 | goto bad; | |
880 | } | |
881 | } | |
882 | ||
65ff5b7d ST |
883 | argv += 10; |
884 | argc -= 10; | |
885 | ||
886 | /* Optional parameters */ | |
887 | if (argc) { | |
888 | as.argc = argc; | |
889 | as.argv = argv; | |
890 | ||
891 | r = dm_read_arg_group(_args, &as, &opt_params, &ti->error); | |
892 | if (r) | |
893 | goto bad; | |
894 | ||
895 | while (opt_params) { | |
896 | opt_params--; | |
897 | opt_string = dm_shift_arg(&as); | |
898 | if (!opt_string) { | |
899 | ti->error = "Not enough feature arguments"; | |
900 | r = -EINVAL; | |
901 | goto bad; | |
902 | } | |
903 | ||
904 | if (!strcasecmp(opt_string, DM_VERITY_OPT_LOGGING)) | |
905 | v->mode = DM_VERITY_MODE_LOGGING; | |
906 | else if (!strcasecmp(opt_string, DM_VERITY_OPT_RESTART)) | |
907 | v->mode = DM_VERITY_MODE_RESTART; | |
908 | else { | |
909 | ti->error = "Invalid feature arguments"; | |
910 | r = -EINVAL; | |
911 | goto bad; | |
912 | } | |
913 | } | |
914 | } | |
915 | ||
a4ffc152 | 916 | v->hash_per_block_bits = |
553d8fe0 | 917 | __fls((1 << v->hash_dev_block_bits) / v->digest_size); |
a4ffc152 MP |
918 | |
919 | v->levels = 0; | |
920 | if (v->data_blocks) | |
921 | while (v->hash_per_block_bits * v->levels < 64 && | |
922 | (unsigned long long)(v->data_blocks - 1) >> | |
923 | (v->hash_per_block_bits * v->levels)) | |
924 | v->levels++; | |
925 | ||
926 | if (v->levels > DM_VERITY_MAX_LEVELS) { | |
927 | ti->error = "Too many tree levels"; | |
928 | r = -E2BIG; | |
929 | goto bad; | |
930 | } | |
931 | ||
932 | hash_position = v->hash_start; | |
933 | for (i = v->levels - 1; i >= 0; i--) { | |
934 | sector_t s; | |
935 | v->hash_level_block[i] = hash_position; | |
b1bf2de0 MP |
936 | s = (v->data_blocks + ((sector_t)1 << ((i + 1) * v->hash_per_block_bits)) - 1) |
937 | >> ((i + 1) * v->hash_per_block_bits); | |
a4ffc152 MP |
938 | if (hash_position + s < hash_position) { |
939 | ti->error = "Hash device offset overflow"; | |
940 | r = -E2BIG; | |
941 | goto bad; | |
942 | } | |
943 | hash_position += s; | |
944 | } | |
945 | v->hash_blocks = hash_position; | |
946 | ||
947 | v->bufio = dm_bufio_client_create(v->hash_dev->bdev, | |
948 | 1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux), | |
949 | dm_bufio_alloc_callback, NULL); | |
950 | if (IS_ERR(v->bufio)) { | |
951 | ti->error = "Cannot initialize dm-bufio"; | |
952 | r = PTR_ERR(v->bufio); | |
953 | v->bufio = NULL; | |
954 | goto bad; | |
955 | } | |
956 | ||
957 | if (dm_bufio_get_device_size(v->bufio) < v->hash_blocks) { | |
958 | ti->error = "Hash device is too small"; | |
959 | r = -E2BIG; | |
960 | goto bad; | |
961 | } | |
962 | ||
e42c3f91 | 963 | ti->per_bio_data_size = roundup(sizeof(struct dm_verity_io) + v->shash_descsize + v->digest_size * 2, __alignof__(struct dm_verity_io)); |
a4ffc152 MP |
964 | |
965 | v->vec_mempool = mempool_create_kmalloc_pool(DM_VERITY_MEMPOOL_SIZE, | |
966 | BIO_MAX_PAGES * sizeof(struct bio_vec)); | |
967 | if (!v->vec_mempool) { | |
968 | ti->error = "Cannot allocate vector mempool"; | |
969 | r = -ENOMEM; | |
970 | goto bad; | |
971 | } | |
972 | ||
973 | /* WQ_UNBOUND greatly improves performance when running on ramdisk */ | |
974 | v->verify_wq = alloc_workqueue("kverityd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND, num_online_cpus()); | |
975 | if (!v->verify_wq) { | |
976 | ti->error = "Cannot allocate workqueue"; | |
977 | r = -ENOMEM; | |
978 | goto bad; | |
979 | } | |
980 | ||
981 | return 0; | |
982 | ||
983 | bad: | |
984 | verity_dtr(ti); | |
985 | ||
986 | return r; | |
987 | } | |
988 | ||
989 | static struct target_type verity_target = { | |
990 | .name = "verity", | |
3b6b7813 | 991 | .version = {1, 2, 0}, |
a4ffc152 MP |
992 | .module = THIS_MODULE, |
993 | .ctr = verity_ctr, | |
994 | .dtr = verity_dtr, | |
995 | .map = verity_map, | |
996 | .status = verity_status, | |
997 | .ioctl = verity_ioctl, | |
998 | .merge = verity_merge, | |
999 | .iterate_devices = verity_iterate_devices, | |
1000 | .io_hints = verity_io_hints, | |
1001 | }; | |
1002 | ||
1003 | static int __init dm_verity_init(void) | |
1004 | { | |
1005 | int r; | |
1006 | ||
1007 | r = dm_register_target(&verity_target); | |
1008 | if (r < 0) | |
1009 | DMERR("register failed %d", r); | |
1010 | ||
1011 | return r; | |
1012 | } | |
1013 | ||
1014 | static void __exit dm_verity_exit(void) | |
1015 | { | |
1016 | dm_unregister_target(&verity_target); | |
1017 | } | |
1018 | ||
1019 | module_init(dm_verity_init); | |
1020 | module_exit(dm_verity_exit); | |
1021 | ||
1022 | MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>"); | |
1023 | MODULE_AUTHOR("Mandeep Baines <msb@chromium.org>"); | |
1024 | MODULE_AUTHOR("Will Drewry <wad@chromium.org>"); | |
1025 | MODULE_DESCRIPTION(DM_NAME " target for transparent disk integrity checking"); | |
1026 | MODULE_LICENSE("GPL"); |