blob: 5c5d30cb6ec59bba067fa3f97808353004ea8aec [file] [log] [blame]
Mikulas Patockaa4ffc152012-03-28 18:43:38 +01001/*
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
Sami Tolvanenffa39382015-12-03 16:01:51 -050017#include "dm-verity.h"
Sami Tolvanena739ff32015-12-03 14:26:30 +000018#include "dm-verity-fec.h"
Mikulas Patockaa4ffc152012-03-28 18:43:38 +010019
20#include <linux/module.h>
Sami Tolvanen65ff5b72015-03-18 15:52:14 +000021#include <linux/reboot.h>
Mikulas Patockaa4ffc152012-03-28 18:43:38 +010022
23#define DM_MSG_PREFIX "verity"
24
Sami Tolvanen65ff5b72015-03-18 15:52:14 +000025#define DM_VERITY_ENV_LENGTH 42
26#define DM_VERITY_ENV_VAR_NAME "DM_VERITY_ERR_BLOCK_NR"
27
Mikulas Patockaa4ffc152012-03-28 18:43:38 +010028#define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144
29
Sami Tolvanen65ff5b72015-03-18 15:52:14 +000030#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"
Sami Tolvanen0cc37c22015-12-03 14:26:31 +000034#define DM_VERITY_OPT_IGN_ZEROES "ignore_zero_blocks"
Mikulas Patockaa4ffc152012-03-28 18:43:38 +010035
Sami Tolvanen0cc37c22015-12-03 14:26:31 +000036#define DM_VERITY_OPTS_MAX (2 + DM_VERITY_OPTS_FEC)
Sami Tolvanen753c1fd2015-11-05 02:02:32 +000037
Mikulas Patockaa4ffc152012-03-28 18:43:38 +010038static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE;
39
40module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR);
41
Mikulas Patocka3b6b7812013-03-20 17:21:25 +000042struct dm_verity_prefetch_work {
43 struct work_struct work;
44 struct dm_verity *v;
45 sector_t block;
46 unsigned n_blocks;
47};
48
Mikulas Patockaa4ffc152012-03-28 18:43:38 +010049/*
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 */
61struct buffer_aux {
62 int hash_verified;
63};
64
65/*
66 * Initialize struct buffer_aux for a freshly created buffer.
67 */
68static 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 */
78static 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 */
89static 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
Sami Tolvanen6dbeda32015-11-05 02:02:31 +000095/*
96 * Wrapper for crypto_shash_init, which handles verity salting.
97 */
98static 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
124static 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
135static 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
Sami Tolvanenffa39382015-12-03 16:01:51 -0500157int verity_hash(struct dm_verity *v, struct shash_desc *desc,
158 const u8 *data, size_t len, u8 *digest)
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000159{
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
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100173static 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
191/*
Sami Tolvanen65ff5b72015-03-18 15:52:14 +0000192 * Handle verification errors.
193 */
194static 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
232out:
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
242/*
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100243 * Verify hash of a metadata block pertaining to the specified data block
244 * ("block" argument) at a specified level ("level" argument).
245 *
Sami Tolvanenffa39382015-12-03 16:01:51 -0500246 * 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).
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100248 *
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
Sami Tolvanenffa39382015-12-03 16:01:51 -0500251 * against current value of verity_io_want_digest(v, io).
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100252 */
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000253static 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)
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100256{
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100257 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);
viresh kumarfc0a4462015-08-10 11:42:26 +0530267 if (IS_ERR(data))
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100268 return PTR_ERR(data);
269
270 aux = dm_bufio_get_aux_data(buf);
271
272 if (!aux->hash_verified) {
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100273 if (skip_unverified) {
274 r = 1;
275 goto release_ret_r;
276 }
277
Sami Tolvanenffa39382015-12-03 16:01:51 -0500278 r = verity_hash(v, verity_io_hash_desc(v, io),
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000279 data, 1 << v->hash_dev_block_bits,
Sami Tolvanenffa39382015-12-03 16:01:51 -0500280 verity_io_real_digest(v, io));
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000281 if (unlikely(r < 0))
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100282 goto release_ret_r;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100283
Sami Tolvanenffa39382015-12-03 16:01:51 -0500284 if (likely(memcmp(verity_io_real_digest(v, io), want_digest,
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000285 v->digest_size) == 0))
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100286 aux->hash_verified = 1;
Sami Tolvanena739ff32015-12-03 14:26:30 +0000287 else if (verity_fec_decode(v, io,
288 DM_VERITY_BLOCK_TYPE_METADATA,
289 hash_block, data, NULL) == 0)
290 aux->hash_verified = 1;
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000291 else if (verity_handle_err(v,
292 DM_VERITY_BLOCK_TYPE_METADATA,
293 hash_block)) {
294 r = -EIO;
295 goto release_ret_r;
296 }
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100297 }
298
299 data += offset;
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000300 memcpy(want_digest, data, v->digest_size);
301 r = 0;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100302
303release_ret_r:
304 dm_bufio_release(buf);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100305 return r;
306}
307
308/*
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000309 * Find a hash for a given block, write it to digest and verify the integrity
310 * of the hash tree if necessary.
311 */
Sami Tolvanenffa39382015-12-03 16:01:51 -0500312int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000313 sector_t block, u8 *digest, bool *is_zero)
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000314{
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000315 int r = 0, i;
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000316
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))
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000327 goto out;
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000328 }
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))
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000335 goto out;
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000336 }
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000337out:
338 if (!r && v->zero_digest)
339 *is_zero = !memcmp(v->zero_digest, digest, v->digest_size);
340 else
341 *is_zero = false;
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000342
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000343 return r;
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000344}
345
346/*
Sami Tolvanenbb4d73a2015-12-03 16:30:36 -0500347 * Calls function process for 1 << v->data_dev_block_bits bytes in the bio_vec
348 * starting from iter.
349 */
350int 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;
357 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_bio_data_size);
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
384static 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
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000390static 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
Sami Tolvanenbb4d73a2015-12-03 16:30:36 -0500397/*
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100398 * Verify one "dm_verity_io" structure.
399 */
400static int verity_verify_io(struct dm_verity_io *io)
401{
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000402 bool is_zero;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100403 struct dm_verity *v = io->v;
Sami Tolvanenbb4d73a2015-12-03 16:30:36 -0500404 struct bvec_iter start;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100405 unsigned b;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100406
407 for (b = 0; b < io->n_blocks; b++) {
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100408 int r;
Sami Tolvanenffa39382015-12-03 16:01:51 -0500409 struct shash_desc *desc = verity_io_hash_desc(v, io);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100410
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000411 r = verity_hash_for_block(v, io, io->block + b,
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000412 verity_io_want_digest(v, io),
413 &is_zero);
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000414 if (unlikely(r < 0))
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100415 return r;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100416
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000417 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
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000430 r = verity_hash_init(v, desc);
431 if (unlikely(r < 0))
432 return r;
433
Sami Tolvanenbb4d73a2015-12-03 16:30:36 -0500434 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;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100438
Sami Tolvanenffa39382015-12-03 16:01:51 -0500439 r = verity_hash_final(v, desc, verity_io_real_digest(v, io));
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000440 if (unlikely(r < 0))
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100441 return r;
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000442
Sami Tolvanenffa39382015-12-03 16:01:51 -0500443 if (likely(memcmp(verity_io_real_digest(v, io),
444 verity_io_want_digest(v, io), v->digest_size) == 0))
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000445 continue;
Sami Tolvanena739ff32015-12-03 14:26:30 +0000446 else if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_DATA,
447 io->block + b, NULL, &start) == 0)
448 continue;
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000449 else if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA,
Sami Tolvanena739ff32015-12-03 14:26:30 +0000450 io->block + b))
Sami Tolvanen6dbeda32015-11-05 02:02:31 +0000451 return -EIO;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100452 }
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100453
454 return 0;
455}
456
457/*
458 * End one "io" structure with a given error.
459 */
460static void verity_finish_io(struct dm_verity_io *io, int error)
461{
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100462 struct dm_verity *v = io->v;
Mikulas Patockae42c3f92012-12-21 20:23:38 +0000463 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_bio_data_size);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100464
465 bio->bi_end_io = io->orig_bi_end_io;
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200466 bio->bi_error = error;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100467
Sami Tolvanena739ff32015-12-03 14:26:30 +0000468 verity_fec_finish_io(io);
469
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200470 bio_endio(bio);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100471}
472
473static 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
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200480static void verity_end_io(struct bio *bio)
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100481{
482 struct dm_verity_io *io = bio->bi_private;
483
Sami Tolvanena739ff32015-12-03 14:26:30 +0000484 if (bio->bi_error && !verity_fec_is_enabled(io->v)) {
Christoph Hellwig4246a0b2015-07-20 15:29:37 +0200485 verity_finish_io(io, bio->bi_error);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100486 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 */
Mikulas Patocka3b6b7812013-03-20 17:21:25 +0000498static void verity_prefetch_io(struct work_struct *work)
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100499{
Mikulas Patocka3b6b7812013-03-20 17:21:25 +0000500 struct dm_verity_prefetch_work *pw =
501 container_of(work, struct dm_verity_prefetch_work, work);
502 struct dm_verity *v = pw->v;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100503 int i;
504
505 for (i = v->levels - 2; i >= 0; i--) {
506 sector_t hash_block_start;
507 sector_t hash_block_end;
Mikulas Patocka3b6b7812013-03-20 17:21:25 +0000508 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);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100510 if (!i) {
Mikulas Patockafe5fe902012-10-12 16:59:46 +0100511 unsigned cluster = ACCESS_ONCE(dm_verity_prefetch_cluster);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100512
513 cluster >>= v->data_dev_block_bits;
514 if (unlikely(!cluster))
515 goto no_prefetch_cluster;
516
517 if (unlikely(cluster & (cluster - 1)))
Mikulas Patocka553d8fe2013-07-10 23:41:17 +0100518 cluster = 1 << __fls(cluster);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100519
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 }
525no_prefetch_cluster:
526 dm_bufio_prefetch(v->bufio, hash_block_start,
527 hash_block_end - hash_block_start + 1);
528 }
Mikulas Patocka3b6b7812013-03-20 17:21:25 +0000529
530 kfree(pw);
531}
532
533static 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);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100548}
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 */
Mikulas Patocka7de3ee52012-12-21 20:23:41 +0000554static int verity_map(struct dm_target *ti, struct bio *bio)
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100555{
556 struct dm_verity *v = ti->private;
557 struct dm_verity_io *io;
558
559 bio->bi_bdev = v->data_dev->bdev;
Kent Overstreet4f024f32013-10-11 15:44:27 -0700560 bio->bi_iter.bi_sector = verity_map_sector(v, bio->bi_iter.bi_sector);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100561
Kent Overstreet4f024f32013-10-11 15:44:27 -0700562 if (((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) &
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100563 ((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) {
564 DMERR_LIMIT("unaligned io");
565 return -EIO;
566 }
567
Kent Overstreetf73a1c72012-09-25 15:05:12 -0700568 if (bio_end_sector(bio) >>
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100569 (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
Mikulas Patockae42c3f92012-12-21 20:23:38 +0000577 io = dm_per_bio_data(bio, ti->per_bio_data_size);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100578 io->v = v;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100579 io->orig_bi_end_io = bio->bi_end_io;
Kent Overstreet4f024f32013-10-11 15:44:27 -0700580 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;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100582
583 bio->bi_end_io = verity_end_io;
584 bio->bi_private = io;
Kent Overstreet003b5c52013-10-11 15:45:43 -0700585 io->iter = bio->bi_iter;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100586
Sami Tolvanena739ff32015-12-03 14:26:30 +0000587 verity_fec_init_io(io);
588
Mikulas Patocka3b6b7812013-03-20 17:21:25 +0000589 verity_submit_prefetch(v, io);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100590
591 generic_make_request(bio);
592
593 return DM_MAPIO_SUBMITTED;
594}
595
596/*
597 * Status: V (valid) or C (corruption found)
598 */
Mikulas Patockafd7c0922013-03-01 22:45:44 +0000599static void verity_status(struct dm_target *ti, status_type_t type,
600 unsigned status_flags, char *result, unsigned maxlen)
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100601{
602 struct dm_verity *v = ti->private;
Sami Tolvanena739ff32015-12-03 14:26:30 +0000603 unsigned args = 0;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100604 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]);
Sami Tolvanena739ff32015-12-03 14:26:30 +0000630 if (v->mode != DM_VERITY_MODE_EIO)
631 args++;
632 if (verity_fec_is_enabled(v))
633 args += DM_VERITY_OPTS_FEC;
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000634 if (v->zero_digest)
635 args++;
Sami Tolvanena739ff32015-12-03 14:26:30 +0000636 if (!args)
637 return;
638 DMEMIT(" %u", args);
Sami Tolvanen65ff5b72015-03-18 15:52:14 +0000639 if (v->mode != DM_VERITY_MODE_EIO) {
Sami Tolvanena739ff32015-12-03 14:26:30 +0000640 DMEMIT(" ");
Sami Tolvanen65ff5b72015-03-18 15:52:14 +0000641 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 }
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000652 if (v->zero_digest)
653 DMEMIT(" " DM_VERITY_OPT_IGN_ZEROES);
Sami Tolvanena739ff32015-12-03 14:26:30 +0000654 sz = verity_fec_status_table(v, sz, result, maxlen);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100655 break;
656 }
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100657}
658
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200659static int verity_prepare_ioctl(struct dm_target *ti,
660 struct block_device **bdev, fmode_t *mode)
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100661{
662 struct dm_verity *v = ti->private;
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200663
664 *bdev = v->data_dev->bdev;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100665
666 if (v->data_start ||
667 ti->len != i_size_read(v->data_dev->bdev->bd_inode) >> SECTOR_SHIFT)
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200668 return 1;
669 return 0;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100670}
671
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100672static 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
680static 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
693static 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
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100700 if (v->bufio)
701 dm_bufio_client_destroy(v->bufio);
702
703 kfree(v->salt);
704 kfree(v->root_digest);
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000705 kfree(v->zero_digest);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100706
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
Sami Tolvanena739ff32015-12-03 14:26:30 +0000718 verity_fec_dtr(v);
719
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100720 kfree(v);
721}
722
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000723static 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
747out:
748 kfree(desc);
749 kfree(zero_data);
750
751 return r;
752}
753
Sami Tolvanen753c1fd2015-11-05 02:02:32 +0000754static 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;
Sami Tolvanena739ff32015-12-03 14:26:30 +0000783
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000784 } 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
Sami Tolvanena739ff32015-12-03 14:26:30 +0000792 } 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;
Sami Tolvanen753c1fd2015-11-05 02:02:32 +0000797 }
798
799 ti->error = "Unrecognized verity feature request";
800 return -EINVAL;
801 } while (argc && !r);
802
803 return r;
804}
805
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100806/*
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 */
820static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
821{
822 struct dm_verity *v;
Sami Tolvanen65ff5b72015-03-18 15:52:14 +0000823 struct dm_arg_set as;
Sami Tolvanen753c1fd2015-11-05 02:02:32 +0000824 unsigned int num;
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100825 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
Sami Tolvanena739ff32015-12-03 14:26:30 +0000839 r = verity_fec_ctr_alloc(v);
840 if (r)
841 goto bad;
842
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100843 if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) {
844 ti->error = "Device must be readonly";
845 r = -EINVAL;
846 goto bad;
847 }
848
Sami Tolvanen65ff5b72015-03-18 15:52:14 +0000849 if (argc < 10) {
850 ti->error = "Not enough arguments";
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100851 r = -EINVAL;
852 goto bad;
853 }
854
Mikulas Patocka5d8be842013-07-10 23:41:17 +0100855 if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 ||
856 num > 1) {
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100857 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 }
Mikulas Patocka553d8fe2013-07-10 23:41:17 +0100883 v->data_dev_block_bits = __ffs(num);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100884
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 }
Mikulas Patocka553d8fe2013-07-10 23:41:17 +0100893 v->hash_dev_block_bits = __ffs(num);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100894
895 if (sscanf(argv[5], "%llu%c", &num_ll, &dummy) != 1 ||
Mikulas Patocka1d55f6b2012-09-26 23:45:48 +0100896 (sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT))
897 >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll) {
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100898 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 ||
Mikulas Patocka1d55f6b2012-09-26 23:45:48 +0100911 (sector_t)(num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT))
912 >> (v->hash_dev_block_bits - SECTOR_SHIFT) != num_ll) {
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100913 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
Sami Tolvanen65ff5b72015-03-18 15:52:14 +0000971 argv += 10;
972 argc -= 10;
973
974 /* Optional parameters */
975 if (argc) {
976 as.argc = argc;
977 as.argv = argv;
978
Sami Tolvanen753c1fd2015-11-05 02:02:32 +0000979 r = verity_parse_opt_args(&as, v);
980 if (r < 0)
Sami Tolvanen65ff5b72015-03-18 15:52:14 +0000981 goto bad;
Sami Tolvanen65ff5b72015-03-18 15:52:14 +0000982 }
983
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100984 v->hash_per_block_bits =
Mikulas Patocka553d8fe2013-07-10 23:41:17 +0100985 __fls((1 << v->hash_dev_block_bits) / v->digest_size);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +0100986
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;
Mikulas Patockab1bf2de2013-07-10 23:41:16 +01001004 s = (v->data_blocks + ((sector_t)1 << ((i + 1) * v->hash_per_block_bits)) - 1)
1005 >> ((i + 1) * v->hash_per_block_bits);
Mikulas Patockaa4ffc152012-03-28 18:43:38 +01001006 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
Mikulas Patockaa4ffc152012-03-28 18:43:38 +01001031 /* 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
Sami Tolvanena739ff32015-12-03 14:26:30 +00001039 ti->per_bio_data_size = sizeof(struct dm_verity_io) +
1040 v->shash_descsize + v->digest_size * 2;
1041
1042 r = verity_fec_ctr(v);
1043 if (r)
1044 goto bad;
1045
1046 ti->per_bio_data_size = roundup(ti->per_bio_data_size,
1047 __alignof__(struct dm_verity_io));
1048
Mikulas Patockaa4ffc152012-03-28 18:43:38 +01001049 return 0;
1050
1051bad:
1052 verity_dtr(ti);
1053
1054 return r;
1055}
1056
1057static struct target_type verity_target = {
1058 .name = "verity",
Sami Tolvanena739ff32015-12-03 14:26:30 +00001059 .version = {1, 3, 0},
Mikulas Patockaa4ffc152012-03-28 18:43:38 +01001060 .module = THIS_MODULE,
1061 .ctr = verity_ctr,
1062 .dtr = verity_dtr,
1063 .map = verity_map,
1064 .status = verity_status,
Christoph Hellwige56f81e2015-10-15 14:10:50 +02001065 .prepare_ioctl = verity_prepare_ioctl,
Mikulas Patockaa4ffc152012-03-28 18:43:38 +01001066 .iterate_devices = verity_iterate_devices,
1067 .io_hints = verity_io_hints,
1068};
1069
1070static 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
1081static void __exit dm_verity_exit(void)
1082{
1083 dm_unregister_target(&verity_target);
1084}
1085
1086module_init(dm_verity_init);
1087module_exit(dm_verity_exit);
1088
1089MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>");
1090MODULE_AUTHOR("Mandeep Baines <msb@chromium.org>");
1091MODULE_AUTHOR("Will Drewry <wad@chromium.org>");
1092MODULE_DESCRIPTION(DM_NAME " target for transparent disk integrity checking");
1093MODULE_LICENSE("GPL");