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16#include "dm-verity.h"
17#include "dm-verity-fec.h"
18#include "dm-verity-verify-sig.h"
19#include <linux/module.h>
20#include <linux/reboot.h>
21
22#define DM_MSG_PREFIX "verity"
23
24#define DM_VERITY_ENV_LENGTH 42
25#define DM_VERITY_ENV_VAR_NAME "DM_VERITY_ERR_BLOCK_NR"
26
27#define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144
28
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"
33#define DM_VERITY_OPT_PANIC "panic_on_corruption"
34#define DM_VERITY_OPT_IGN_ZEROES "ignore_zero_blocks"
35#define DM_VERITY_OPT_AT_MOST_ONCE "check_at_most_once"
36
37#define DM_VERITY_OPTS_MAX (3 + DM_VERITY_OPTS_FEC + \
38 DM_VERITY_ROOT_HASH_VERIFICATION_OPTS)
39
40static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE;
41
42module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR);
43
44struct dm_verity_prefetch_work {
45 struct work_struct work;
46 struct dm_verity *v;
47 sector_t block;
48 unsigned n_blocks;
49};
50
51
52
53
54
55
56
57
58
59
60
61
62
63struct buffer_aux {
64 int hash_verified;
65};
66
67
68
69
70static void dm_bufio_alloc_callback(struct dm_buffer *buf)
71{
72 struct buffer_aux *aux = dm_bufio_get_aux_data(buf);
73
74 aux->hash_verified = 0;
75}
76
77
78
79
80static sector_t verity_map_sector(struct dm_verity *v, sector_t bi_sector)
81{
82 return v->data_start + dm_target_offset(v->ti, bi_sector);
83}
84
85
86
87
88
89
90
91static sector_t verity_position_at_level(struct dm_verity *v, sector_t block,
92 int level)
93{
94 return block >> (level * v->hash_per_block_bits);
95}
96
97static int verity_hash_update(struct dm_verity *v, struct ahash_request *req,
98 const u8 *data, size_t len,
99 struct crypto_wait *wait)
100{
101 struct scatterlist sg;
102
103 if (likely(!is_vmalloc_addr(data))) {
104 sg_init_one(&sg, data, len);
105 ahash_request_set_crypt(req, &sg, NULL, len);
106 return crypto_wait_req(crypto_ahash_update(req), wait);
107 } else {
108 do {
109 int r;
110 size_t this_step = min_t(size_t, len, PAGE_SIZE - offset_in_page(data));
111 flush_kernel_vmap_range((void *)data, this_step);
112 sg_init_table(&sg, 1);
113 sg_set_page(&sg, vmalloc_to_page(data), this_step, offset_in_page(data));
114 ahash_request_set_crypt(req, &sg, NULL, this_step);
115 r = crypto_wait_req(crypto_ahash_update(req), wait);
116 if (unlikely(r))
117 return r;
118 data += this_step;
119 len -= this_step;
120 } while (len);
121 return 0;
122 }
123}
124
125
126
127
128static int verity_hash_init(struct dm_verity *v, struct ahash_request *req,
129 struct crypto_wait *wait)
130{
131 int r;
132
133 ahash_request_set_tfm(req, v->tfm);
134 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP |
135 CRYPTO_TFM_REQ_MAY_BACKLOG,
136 crypto_req_done, (void *)wait);
137 crypto_init_wait(wait);
138
139 r = crypto_wait_req(crypto_ahash_init(req), wait);
140
141 if (unlikely(r < 0)) {
142 DMERR("crypto_ahash_init failed: %d", r);
143 return r;
144 }
145
146 if (likely(v->salt_size && (v->version >= 1)))
147 r = verity_hash_update(v, req, v->salt, v->salt_size, wait);
148
149 return r;
150}
151
152static int verity_hash_final(struct dm_verity *v, struct ahash_request *req,
153 u8 *digest, struct crypto_wait *wait)
154{
155 int r;
156
157 if (unlikely(v->salt_size && (!v->version))) {
158 r = verity_hash_update(v, req, v->salt, v->salt_size, wait);
159
160 if (r < 0) {
161 DMERR("verity_hash_final failed updating salt: %d", r);
162 goto out;
163 }
164 }
165
166 ahash_request_set_crypt(req, NULL, digest, 0);
167 r = crypto_wait_req(crypto_ahash_final(req), wait);
168out:
169 return r;
170}
171
172int verity_hash(struct dm_verity *v, struct ahash_request *req,
173 const u8 *data, size_t len, u8 *digest)
174{
175 int r;
176 struct crypto_wait wait;
177
178 r = verity_hash_init(v, req, &wait);
179 if (unlikely(r < 0))
180 goto out;
181
182 r = verity_hash_update(v, req, data, len, &wait);
183 if (unlikely(r < 0))
184 goto out;
185
186 r = verity_hash_final(v, req, digest, &wait);
187
188out:
189 return r;
190}
191
192static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level,
193 sector_t *hash_block, unsigned *offset)
194{
195 sector_t position = verity_position_at_level(v, block, level);
196 unsigned idx;
197
198 *hash_block = v->hash_level_block[level] + (position >> v->hash_per_block_bits);
199
200 if (!offset)
201 return;
202
203 idx = position & ((1 << v->hash_per_block_bits) - 1);
204 if (!v->version)
205 *offset = idx * v->digest_size;
206 else
207 *offset = idx << (v->hash_dev_block_bits - v->hash_per_block_bits);
208}
209
210
211
212
213static int verity_handle_err(struct dm_verity *v, enum verity_block_type type,
214 unsigned long long block)
215{
216 char verity_env[DM_VERITY_ENV_LENGTH];
217 char *envp[] = { verity_env, NULL };
218 const char *type_str = "";
219 struct mapped_device *md = dm_table_get_md(v->ti->table);
220
221
222 v->hash_failed = 1;
223
224 if (v->corrupted_errs >= DM_VERITY_MAX_CORRUPTED_ERRS)
225 goto out;
226
227 v->corrupted_errs++;
228
229 switch (type) {
230 case DM_VERITY_BLOCK_TYPE_DATA:
231 type_str = "data";
232 break;
233 case DM_VERITY_BLOCK_TYPE_METADATA:
234 type_str = "metadata";
235 break;
236 default:
237 BUG();
238 }
239
240 DMERR_LIMIT("%s: %s block %llu is corrupted", v->data_dev->name,
241 type_str, block);
242
243 if (v->corrupted_errs == DM_VERITY_MAX_CORRUPTED_ERRS)
244 DMERR("%s: reached maximum errors", v->data_dev->name);
245
246 snprintf(verity_env, DM_VERITY_ENV_LENGTH, "%s=%d,%llu",
247 DM_VERITY_ENV_VAR_NAME, type, block);
248
249 kobject_uevent_env(&disk_to_dev(dm_disk(md))->kobj, KOBJ_CHANGE, envp);
250
251out:
252 if (v->mode == DM_VERITY_MODE_LOGGING)
253 return 0;
254
255 if (v->mode == DM_VERITY_MODE_RESTART)
256 kernel_restart("dm-verity device corrupted");
257
258 if (v->mode == DM_VERITY_MODE_PANIC)
259 panic("dm-verity device corrupted");
260
261 return 1;
262}
263
264
265
266
267
268
269
270
271
272
273
274
275static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
276 sector_t block, int level, bool skip_unverified,
277 u8 *want_digest)
278{
279 struct dm_buffer *buf;
280 struct buffer_aux *aux;
281 u8 *data;
282 int r;
283 sector_t hash_block;
284 unsigned offset;
285
286 verity_hash_at_level(v, block, level, &hash_block, &offset);
287
288 data = dm_bufio_read(v->bufio, hash_block, &buf);
289 if (IS_ERR(data))
290 return PTR_ERR(data);
291
292 aux = dm_bufio_get_aux_data(buf);
293
294 if (!aux->hash_verified) {
295 if (skip_unverified) {
296 r = 1;
297 goto release_ret_r;
298 }
299
300 r = verity_hash(v, verity_io_hash_req(v, io),
301 data, 1 << v->hash_dev_block_bits,
302 verity_io_real_digest(v, io));
303 if (unlikely(r < 0))
304 goto release_ret_r;
305
306 if (likely(memcmp(verity_io_real_digest(v, io), want_digest,
307 v->digest_size) == 0))
308 aux->hash_verified = 1;
309 else if (verity_fec_decode(v, io,
310 DM_VERITY_BLOCK_TYPE_METADATA,
311 hash_block, data, NULL) == 0)
312 aux->hash_verified = 1;
313 else if (verity_handle_err(v,
314 DM_VERITY_BLOCK_TYPE_METADATA,
315 hash_block)) {
316 r = -EIO;
317 goto release_ret_r;
318 }
319 }
320
321 data += offset;
322 memcpy(want_digest, data, v->digest_size);
323 r = 0;
324
325release_ret_r:
326 dm_bufio_release(buf);
327 return r;
328}
329
330
331
332
333
334int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
335 sector_t block, u8 *digest, bool *is_zero)
336{
337 int r = 0, i;
338
339 if (likely(v->levels)) {
340
341
342
343
344
345
346
347 r = verity_verify_level(v, io, block, 0, true, digest);
348 if (likely(r <= 0))
349 goto out;
350 }
351
352 memcpy(digest, v->root_digest, v->digest_size);
353
354 for (i = v->levels - 1; i >= 0; i--) {
355 r = verity_verify_level(v, io, block, i, false, digest);
356 if (unlikely(r))
357 goto out;
358 }
359out:
360 if (!r && v->zero_digest)
361 *is_zero = !memcmp(v->zero_digest, digest, v->digest_size);
362 else
363 *is_zero = false;
364
365 return r;
366}
367
368
369
370
371static int verity_for_io_block(struct dm_verity *v, struct dm_verity_io *io,
372 struct bvec_iter *iter, struct crypto_wait *wait)
373{
374 unsigned int todo = 1 << v->data_dev_block_bits;
375 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
376 struct scatterlist sg;
377 struct ahash_request *req = verity_io_hash_req(v, io);
378
379 do {
380 int r;
381 unsigned int len;
382 struct bio_vec bv = bio_iter_iovec(bio, *iter);
383
384 sg_init_table(&sg, 1);
385
386 len = bv.bv_len;
387
388 if (likely(len >= todo))
389 len = todo;
390
391
392
393
394
395 sg_set_page(&sg, bv.bv_page, len, bv.bv_offset);
396 ahash_request_set_crypt(req, &sg, NULL, len);
397 r = crypto_wait_req(crypto_ahash_update(req), wait);
398
399 if (unlikely(r < 0)) {
400 DMERR("verity_for_io_block crypto op failed: %d", r);
401 return r;
402 }
403
404 bio_advance_iter(bio, iter, len);
405 todo -= len;
406 } while (todo);
407
408 return 0;
409}
410
411
412
413
414
415int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
416 struct bvec_iter *iter,
417 int (*process)(struct dm_verity *v,
418 struct dm_verity_io *io, u8 *data,
419 size_t len))
420{
421 unsigned todo = 1 << v->data_dev_block_bits;
422 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
423
424 do {
425 int r;
426 u8 *page;
427 unsigned len;
428 struct bio_vec bv = bio_iter_iovec(bio, *iter);
429
430 page = kmap_atomic(bv.bv_page);
431 len = bv.bv_len;
432
433 if (likely(len >= todo))
434 len = todo;
435
436 r = process(v, io, page + bv.bv_offset, len);
437 kunmap_atomic(page);
438
439 if (r < 0)
440 return r;
441
442 bio_advance_iter(bio, iter, len);
443 todo -= len;
444 } while (todo);
445
446 return 0;
447}
448
449static int verity_bv_zero(struct dm_verity *v, struct dm_verity_io *io,
450 u8 *data, size_t len)
451{
452 memset(data, 0, len);
453 return 0;
454}
455
456
457
458
459static inline void verity_bv_skip_block(struct dm_verity *v,
460 struct dm_verity_io *io,
461 struct bvec_iter *iter)
462{
463 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
464
465 bio_advance_iter(bio, iter, 1 << v->data_dev_block_bits);
466}
467
468
469
470
471static int verity_verify_io(struct dm_verity_io *io)
472{
473 bool is_zero;
474 struct dm_verity *v = io->v;
475 struct bvec_iter start;
476 unsigned b;
477 struct crypto_wait wait;
478 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
479
480 for (b = 0; b < io->n_blocks; b++) {
481 int r;
482 sector_t cur_block = io->block + b;
483 struct ahash_request *req = verity_io_hash_req(v, io);
484
485 if (v->validated_blocks &&
486 likely(test_bit(cur_block, v->validated_blocks))) {
487 verity_bv_skip_block(v, io, &io->iter);
488 continue;
489 }
490
491 r = verity_hash_for_block(v, io, cur_block,
492 verity_io_want_digest(v, io),
493 &is_zero);
494 if (unlikely(r < 0))
495 return r;
496
497 if (is_zero) {
498
499
500
501
502 r = verity_for_bv_block(v, io, &io->iter,
503 verity_bv_zero);
504 if (unlikely(r < 0))
505 return r;
506
507 continue;
508 }
509
510 r = verity_hash_init(v, req, &wait);
511 if (unlikely(r < 0))
512 return r;
513
514 start = io->iter;
515 r = verity_for_io_block(v, io, &io->iter, &wait);
516 if (unlikely(r < 0))
517 return r;
518
519 r = verity_hash_final(v, req, verity_io_real_digest(v, io),
520 &wait);
521 if (unlikely(r < 0))
522 return r;
523
524 if (likely(memcmp(verity_io_real_digest(v, io),
525 verity_io_want_digest(v, io), v->digest_size) == 0)) {
526 if (v->validated_blocks)
527 set_bit(cur_block, v->validated_blocks);
528 continue;
529 }
530 else if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_DATA,
531 cur_block, NULL, &start) == 0)
532 continue;
533 else {
534 if (bio->bi_status) {
535
536
537
538 return -EIO;
539 }
540 if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA,
541 cur_block))
542 return -EIO;
543 }
544 }
545
546 return 0;
547}
548
549
550
551
552static inline bool verity_is_system_shutting_down(void)
553{
554 return system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF
555 || system_state == SYSTEM_RESTART;
556}
557
558
559
560
561static void verity_finish_io(struct dm_verity_io *io, blk_status_t status)
562{
563 struct dm_verity *v = io->v;
564 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
565
566 bio->bi_end_io = io->orig_bi_end_io;
567 bio->bi_status = status;
568
569 verity_fec_finish_io(io);
570
571 bio_endio(bio);
572}
573
574static void verity_work(struct work_struct *w)
575{
576 struct dm_verity_io *io = container_of(w, struct dm_verity_io, work);
577
578 verity_finish_io(io, errno_to_blk_status(verity_verify_io(io)));
579}
580
581static void verity_end_io(struct bio *bio)
582{
583 struct dm_verity_io *io = bio->bi_private;
584
585 if (bio->bi_status &&
586 (!verity_fec_is_enabled(io->v) || verity_is_system_shutting_down())) {
587 verity_finish_io(io, bio->bi_status);
588 return;
589 }
590
591 INIT_WORK(&io->work, verity_work);
592 queue_work(io->v->verify_wq, &io->work);
593}
594
595
596
597
598
599
600static void verity_prefetch_io(struct work_struct *work)
601{
602 struct dm_verity_prefetch_work *pw =
603 container_of(work, struct dm_verity_prefetch_work, work);
604 struct dm_verity *v = pw->v;
605 int i;
606
607 for (i = v->levels - 2; i >= 0; i--) {
608 sector_t hash_block_start;
609 sector_t hash_block_end;
610 verity_hash_at_level(v, pw->block, i, &hash_block_start, NULL);
611 verity_hash_at_level(v, pw->block + pw->n_blocks - 1, i, &hash_block_end, NULL);
612 if (!i) {
613 unsigned cluster = READ_ONCE(dm_verity_prefetch_cluster);
614
615 cluster >>= v->data_dev_block_bits;
616 if (unlikely(!cluster))
617 goto no_prefetch_cluster;
618
619 if (unlikely(cluster & (cluster - 1)))
620 cluster = 1 << __fls(cluster);
621
622 hash_block_start &= ~(sector_t)(cluster - 1);
623 hash_block_end |= cluster - 1;
624 if (unlikely(hash_block_end >= v->hash_blocks))
625 hash_block_end = v->hash_blocks - 1;
626 }
627no_prefetch_cluster:
628 dm_bufio_prefetch(v->bufio, hash_block_start,
629 hash_block_end - hash_block_start + 1);
630 }
631
632 kfree(pw);
633}
634
635static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io)
636{
637 sector_t block = io->block;
638 unsigned int n_blocks = io->n_blocks;
639 struct dm_verity_prefetch_work *pw;
640
641 if (v->validated_blocks) {
642 while (n_blocks && test_bit(block, v->validated_blocks)) {
643 block++;
644 n_blocks--;
645 }
646 while (n_blocks && test_bit(block + n_blocks - 1,
647 v->validated_blocks))
648 n_blocks--;
649 if (!n_blocks)
650 return;
651 }
652
653 pw = kmalloc(sizeof(struct dm_verity_prefetch_work),
654 GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
655
656 if (!pw)
657 return;
658
659 INIT_WORK(&pw->work, verity_prefetch_io);
660 pw->v = v;
661 pw->block = block;
662 pw->n_blocks = n_blocks;
663 queue_work(v->verify_wq, &pw->work);
664}
665
666
667
668
669
670static int verity_map(struct dm_target *ti, struct bio *bio)
671{
672 struct dm_verity *v = ti->private;
673 struct dm_verity_io *io;
674
675 bio_set_dev(bio, v->data_dev->bdev);
676 bio->bi_iter.bi_sector = verity_map_sector(v, bio->bi_iter.bi_sector);
677
678 if (((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) &
679 ((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) {
680 DMERR_LIMIT("unaligned io");
681 return DM_MAPIO_KILL;
682 }
683
684 if (bio_end_sector(bio) >>
685 (v->data_dev_block_bits - SECTOR_SHIFT) > v->data_blocks) {
686 DMERR_LIMIT("io out of range");
687 return DM_MAPIO_KILL;
688 }
689
690 if (bio_data_dir(bio) == WRITE)
691 return DM_MAPIO_KILL;
692
693 io = dm_per_bio_data(bio, ti->per_io_data_size);
694 io->v = v;
695 io->orig_bi_end_io = bio->bi_end_io;
696 io->block = bio->bi_iter.bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT);
697 io->n_blocks = bio->bi_iter.bi_size >> v->data_dev_block_bits;
698
699 bio->bi_end_io = verity_end_io;
700 bio->bi_private = io;
701 io->iter = bio->bi_iter;
702
703 verity_fec_init_io(io);
704
705 verity_submit_prefetch(v, io);
706
707 submit_bio_noacct(bio);
708
709 return DM_MAPIO_SUBMITTED;
710}
711
712
713
714
715static void verity_status(struct dm_target *ti, status_type_t type,
716 unsigned status_flags, char *result, unsigned maxlen)
717{
718 struct dm_verity *v = ti->private;
719 unsigned args = 0;
720 unsigned sz = 0;
721 unsigned x;
722
723 switch (type) {
724 case STATUSTYPE_INFO:
725 DMEMIT("%c", v->hash_failed ? 'C' : 'V');
726 break;
727 case STATUSTYPE_TABLE:
728 DMEMIT("%u %s %s %u %u %llu %llu %s ",
729 v->version,
730 v->data_dev->name,
731 v->hash_dev->name,
732 1 << v->data_dev_block_bits,
733 1 << v->hash_dev_block_bits,
734 (unsigned long long)v->data_blocks,
735 (unsigned long long)v->hash_start,
736 v->alg_name
737 );
738 for (x = 0; x < v->digest_size; x++)
739 DMEMIT("%02x", v->root_digest[x]);
740 DMEMIT(" ");
741 if (!v->salt_size)
742 DMEMIT("-");
743 else
744 for (x = 0; x < v->salt_size; x++)
745 DMEMIT("%02x", v->salt[x]);
746 if (v->mode != DM_VERITY_MODE_EIO)
747 args++;
748 if (verity_fec_is_enabled(v))
749 args += DM_VERITY_OPTS_FEC;
750 if (v->zero_digest)
751 args++;
752 if (v->validated_blocks)
753 args++;
754 if (v->signature_key_desc)
755 args += DM_VERITY_ROOT_HASH_VERIFICATION_OPTS;
756 if (!args)
757 return;
758 DMEMIT(" %u", args);
759 if (v->mode != DM_VERITY_MODE_EIO) {
760 DMEMIT(" ");
761 switch (v->mode) {
762 case DM_VERITY_MODE_LOGGING:
763 DMEMIT(DM_VERITY_OPT_LOGGING);
764 break;
765 case DM_VERITY_MODE_RESTART:
766 DMEMIT(DM_VERITY_OPT_RESTART);
767 break;
768 case DM_VERITY_MODE_PANIC:
769 DMEMIT(DM_VERITY_OPT_PANIC);
770 break;
771 default:
772 BUG();
773 }
774 }
775 if (v->zero_digest)
776 DMEMIT(" " DM_VERITY_OPT_IGN_ZEROES);
777 if (v->validated_blocks)
778 DMEMIT(" " DM_VERITY_OPT_AT_MOST_ONCE);
779 sz = verity_fec_status_table(v, sz, result, maxlen);
780 if (v->signature_key_desc)
781 DMEMIT(" " DM_VERITY_ROOT_HASH_VERIFICATION_OPT_SIG_KEY
782 " %s", v->signature_key_desc);
783 break;
784
785 case STATUSTYPE_IMA:
786 DMEMIT_TARGET_NAME_VERSION(ti->type);
787 DMEMIT(",hash_failed=%c", v->hash_failed ? 'C' : 'V');
788 DMEMIT(",verity_version=%u", v->version);
789 DMEMIT(",data_device_name=%s", v->data_dev->name);
790 DMEMIT(",hash_device_name=%s", v->hash_dev->name);
791 DMEMIT(",verity_algorithm=%s", v->alg_name);
792
793 DMEMIT(",root_digest=");
794 for (x = 0; x < v->digest_size; x++)
795 DMEMIT("%02x", v->root_digest[x]);
796
797 DMEMIT(",salt=");
798 if (!v->salt_size)
799 DMEMIT("-");
800 else
801 for (x = 0; x < v->salt_size; x++)
802 DMEMIT("%02x", v->salt[x]);
803
804 DMEMIT(",ignore_zero_blocks=%c", v->zero_digest ? 'y' : 'n');
805 DMEMIT(",check_at_most_once=%c", v->validated_blocks ? 'y' : 'n');
806 if (v->signature_key_desc)
807 DMEMIT(",root_hash_sig_key_desc=%s", v->signature_key_desc);
808
809 if (v->mode != DM_VERITY_MODE_EIO) {
810 DMEMIT(",verity_mode=");
811 switch (v->mode) {
812 case DM_VERITY_MODE_LOGGING:
813 DMEMIT(DM_VERITY_OPT_LOGGING);
814 break;
815 case DM_VERITY_MODE_RESTART:
816 DMEMIT(DM_VERITY_OPT_RESTART);
817 break;
818 case DM_VERITY_MODE_PANIC:
819 DMEMIT(DM_VERITY_OPT_PANIC);
820 break;
821 default:
822 DMEMIT("invalid");
823 }
824 }
825 DMEMIT(";");
826 break;
827 }
828}
829
830static int verity_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
831{
832 struct dm_verity *v = ti->private;
833
834 *bdev = v->data_dev->bdev;
835
836 if (v->data_start ||
837 ti->len != i_size_read(v->data_dev->bdev->bd_inode) >> SECTOR_SHIFT)
838 return 1;
839 return 0;
840}
841
842static int verity_iterate_devices(struct dm_target *ti,
843 iterate_devices_callout_fn fn, void *data)
844{
845 struct dm_verity *v = ti->private;
846
847 return fn(ti, v->data_dev, v->data_start, ti->len, data);
848}
849
850static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits)
851{
852 struct dm_verity *v = ti->private;
853
854 if (limits->logical_block_size < 1 << v->data_dev_block_bits)
855 limits->logical_block_size = 1 << v->data_dev_block_bits;
856
857 if (limits->physical_block_size < 1 << v->data_dev_block_bits)
858 limits->physical_block_size = 1 << v->data_dev_block_bits;
859
860 blk_limits_io_min(limits, limits->logical_block_size);
861}
862
863static void verity_dtr(struct dm_target *ti)
864{
865 struct dm_verity *v = ti->private;
866
867 if (v->verify_wq)
868 destroy_workqueue(v->verify_wq);
869
870 if (v->bufio)
871 dm_bufio_client_destroy(v->bufio);
872
873 kvfree(v->validated_blocks);
874 kfree(v->salt);
875 kfree(v->root_digest);
876 kfree(v->zero_digest);
877
878 if (v->tfm)
879 crypto_free_ahash(v->tfm);
880
881 kfree(v->alg_name);
882
883 if (v->hash_dev)
884 dm_put_device(ti, v->hash_dev);
885
886 if (v->data_dev)
887 dm_put_device(ti, v->data_dev);
888
889 verity_fec_dtr(v);
890
891 kfree(v->signature_key_desc);
892
893 kfree(v);
894}
895
896static int verity_alloc_most_once(struct dm_verity *v)
897{
898 struct dm_target *ti = v->ti;
899
900
901 if (v->data_blocks > INT_MAX) {
902 ti->error = "device too large to use check_at_most_once";
903 return -E2BIG;
904 }
905
906 v->validated_blocks = kvcalloc(BITS_TO_LONGS(v->data_blocks),
907 sizeof(unsigned long),
908 GFP_KERNEL);
909 if (!v->validated_blocks) {
910 ti->error = "failed to allocate bitset for check_at_most_once";
911 return -ENOMEM;
912 }
913
914 return 0;
915}
916
917static int verity_alloc_zero_digest(struct dm_verity *v)
918{
919 int r = -ENOMEM;
920 struct ahash_request *req;
921 u8 *zero_data;
922
923 v->zero_digest = kmalloc(v->digest_size, GFP_KERNEL);
924
925 if (!v->zero_digest)
926 return r;
927
928 req = kmalloc(v->ahash_reqsize, GFP_KERNEL);
929
930 if (!req)
931 return r;
932
933 zero_data = kzalloc(1 << v->data_dev_block_bits, GFP_KERNEL);
934
935 if (!zero_data)
936 goto out;
937
938 r = verity_hash(v, req, zero_data, 1 << v->data_dev_block_bits,
939 v->zero_digest);
940
941out:
942 kfree(req);
943 kfree(zero_data);
944
945 return r;
946}
947
948static inline bool verity_is_verity_mode(const char *arg_name)
949{
950 return (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING) ||
951 !strcasecmp(arg_name, DM_VERITY_OPT_RESTART) ||
952 !strcasecmp(arg_name, DM_VERITY_OPT_PANIC));
953}
954
955static int verity_parse_verity_mode(struct dm_verity *v, const char *arg_name)
956{
957 if (v->mode)
958 return -EINVAL;
959
960 if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING))
961 v->mode = DM_VERITY_MODE_LOGGING;
962 else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART))
963 v->mode = DM_VERITY_MODE_RESTART;
964 else if (!strcasecmp(arg_name, DM_VERITY_OPT_PANIC))
965 v->mode = DM_VERITY_MODE_PANIC;
966
967 return 0;
968}
969
970static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
971 struct dm_verity_sig_opts *verify_args)
972{
973 int r;
974 unsigned argc;
975 struct dm_target *ti = v->ti;
976 const char *arg_name;
977
978 static const struct dm_arg _args[] = {
979 {0, DM_VERITY_OPTS_MAX, "Invalid number of feature args"},
980 };
981
982 r = dm_read_arg_group(_args, as, &argc, &ti->error);
983 if (r)
984 return -EINVAL;
985
986 if (!argc)
987 return 0;
988
989 do {
990 arg_name = dm_shift_arg(as);
991 argc--;
992
993 if (verity_is_verity_mode(arg_name)) {
994 r = verity_parse_verity_mode(v, arg_name);
995 if (r) {
996 ti->error = "Conflicting error handling parameters";
997 return r;
998 }
999 continue;
1000
1001 } else if (!strcasecmp(arg_name, DM_VERITY_OPT_IGN_ZEROES)) {
1002 r = verity_alloc_zero_digest(v);
1003 if (r) {
1004 ti->error = "Cannot allocate zero digest";
1005 return r;
1006 }
1007 continue;
1008
1009 } else if (!strcasecmp(arg_name, DM_VERITY_OPT_AT_MOST_ONCE)) {
1010 r = verity_alloc_most_once(v);
1011 if (r)
1012 return r;
1013 continue;
1014
1015 } else if (verity_is_fec_opt_arg(arg_name)) {
1016 r = verity_fec_parse_opt_args(as, v, &argc, arg_name);
1017 if (r)
1018 return r;
1019 continue;
1020 } else if (verity_verify_is_sig_opt_arg(arg_name)) {
1021 r = verity_verify_sig_parse_opt_args(as, v,
1022 verify_args,
1023 &argc, arg_name);
1024 if (r)
1025 return r;
1026 continue;
1027
1028 }
1029
1030 ti->error = "Unrecognized verity feature request";
1031 return -EINVAL;
1032 } while (argc && !r);
1033
1034 return r;
1035}
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
1052{
1053 struct dm_verity *v;
1054 struct dm_verity_sig_opts verify_args = {0};
1055 struct dm_arg_set as;
1056 unsigned int num;
1057 unsigned long long num_ll;
1058 int r;
1059 int i;
1060 sector_t hash_position;
1061 char dummy;
1062 char *root_hash_digest_to_validate;
1063
1064 v = kzalloc(sizeof(struct dm_verity), GFP_KERNEL);
1065 if (!v) {
1066 ti->error = "Cannot allocate verity structure";
1067 return -ENOMEM;
1068 }
1069 ti->private = v;
1070 v->ti = ti;
1071
1072 r = verity_fec_ctr_alloc(v);
1073 if (r)
1074 goto bad;
1075
1076 if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) {
1077 ti->error = "Device must be readonly";
1078 r = -EINVAL;
1079 goto bad;
1080 }
1081
1082 if (argc < 10) {
1083 ti->error = "Not enough arguments";
1084 r = -EINVAL;
1085 goto bad;
1086 }
1087
1088 if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 ||
1089 num > 1) {
1090 ti->error = "Invalid version";
1091 r = -EINVAL;
1092 goto bad;
1093 }
1094 v->version = num;
1095
1096 r = dm_get_device(ti, argv[1], FMODE_READ, &v->data_dev);
1097 if (r) {
1098 ti->error = "Data device lookup failed";
1099 goto bad;
1100 }
1101
1102 r = dm_get_device(ti, argv[2], FMODE_READ, &v->hash_dev);
1103 if (r) {
1104 ti->error = "Hash device lookup failed";
1105 goto bad;
1106 }
1107
1108 if (sscanf(argv[3], "%u%c", &num, &dummy) != 1 ||
1109 !num || (num & (num - 1)) ||
1110 num < bdev_logical_block_size(v->data_dev->bdev) ||
1111 num > PAGE_SIZE) {
1112 ti->error = "Invalid data device block size";
1113 r = -EINVAL;
1114 goto bad;
1115 }
1116 v->data_dev_block_bits = __ffs(num);
1117
1118 if (sscanf(argv[4], "%u%c", &num, &dummy) != 1 ||
1119 !num || (num & (num - 1)) ||
1120 num < bdev_logical_block_size(v->hash_dev->bdev) ||
1121 num > INT_MAX) {
1122 ti->error = "Invalid hash device block size";
1123 r = -EINVAL;
1124 goto bad;
1125 }
1126 v->hash_dev_block_bits = __ffs(num);
1127
1128 if (sscanf(argv[5], "%llu%c", &num_ll, &dummy) != 1 ||
1129 (sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT))
1130 >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll) {
1131 ti->error = "Invalid data blocks";
1132 r = -EINVAL;
1133 goto bad;
1134 }
1135 v->data_blocks = num_ll;
1136
1137 if (ti->len > (v->data_blocks << (v->data_dev_block_bits - SECTOR_SHIFT))) {
1138 ti->error = "Data device is too small";
1139 r = -EINVAL;
1140 goto bad;
1141 }
1142
1143 if (sscanf(argv[6], "%llu%c", &num_ll, &dummy) != 1 ||
1144 (sector_t)(num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT))
1145 >> (v->hash_dev_block_bits - SECTOR_SHIFT) != num_ll) {
1146 ti->error = "Invalid hash start";
1147 r = -EINVAL;
1148 goto bad;
1149 }
1150 v->hash_start = num_ll;
1151
1152 v->alg_name = kstrdup(argv[7], GFP_KERNEL);
1153 if (!v->alg_name) {
1154 ti->error = "Cannot allocate algorithm name";
1155 r = -ENOMEM;
1156 goto bad;
1157 }
1158
1159 v->tfm = crypto_alloc_ahash(v->alg_name, 0, 0);
1160 if (IS_ERR(v->tfm)) {
1161 ti->error = "Cannot initialize hash function";
1162 r = PTR_ERR(v->tfm);
1163 v->tfm = NULL;
1164 goto bad;
1165 }
1166
1167
1168
1169
1170
1171
1172 DMINFO("%s using implementation \"%s\"", v->alg_name,
1173 crypto_hash_alg_common(v->tfm)->base.cra_driver_name);
1174
1175 v->digest_size = crypto_ahash_digestsize(v->tfm);
1176 if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) {
1177 ti->error = "Digest size too big";
1178 r = -EINVAL;
1179 goto bad;
1180 }
1181 v->ahash_reqsize = sizeof(struct ahash_request) +
1182 crypto_ahash_reqsize(v->tfm);
1183
1184 v->root_digest = kmalloc(v->digest_size, GFP_KERNEL);
1185 if (!v->root_digest) {
1186 ti->error = "Cannot allocate root digest";
1187 r = -ENOMEM;
1188 goto bad;
1189 }
1190 if (strlen(argv[8]) != v->digest_size * 2 ||
1191 hex2bin(v->root_digest, argv[8], v->digest_size)) {
1192 ti->error = "Invalid root digest";
1193 r = -EINVAL;
1194 goto bad;
1195 }
1196 root_hash_digest_to_validate = argv[8];
1197
1198 if (strcmp(argv[9], "-")) {
1199 v->salt_size = strlen(argv[9]) / 2;
1200 v->salt = kmalloc(v->salt_size, GFP_KERNEL);
1201 if (!v->salt) {
1202 ti->error = "Cannot allocate salt";
1203 r = -ENOMEM;
1204 goto bad;
1205 }
1206 if (strlen(argv[9]) != v->salt_size * 2 ||
1207 hex2bin(v->salt, argv[9], v->salt_size)) {
1208 ti->error = "Invalid salt";
1209 r = -EINVAL;
1210 goto bad;
1211 }
1212 }
1213
1214 argv += 10;
1215 argc -= 10;
1216
1217
1218 if (argc) {
1219 as.argc = argc;
1220 as.argv = argv;
1221
1222 r = verity_parse_opt_args(&as, v, &verify_args);
1223 if (r < 0)
1224 goto bad;
1225 }
1226
1227
1228 r = verity_verify_root_hash(root_hash_digest_to_validate,
1229 strlen(root_hash_digest_to_validate),
1230 verify_args.sig,
1231 verify_args.sig_size);
1232 if (r < 0) {
1233 ti->error = "Root hash verification failed";
1234 goto bad;
1235 }
1236 v->hash_per_block_bits =
1237 __fls((1 << v->hash_dev_block_bits) / v->digest_size);
1238
1239 v->levels = 0;
1240 if (v->data_blocks)
1241 while (v->hash_per_block_bits * v->levels < 64 &&
1242 (unsigned long long)(v->data_blocks - 1) >>
1243 (v->hash_per_block_bits * v->levels))
1244 v->levels++;
1245
1246 if (v->levels > DM_VERITY_MAX_LEVELS) {
1247 ti->error = "Too many tree levels";
1248 r = -E2BIG;
1249 goto bad;
1250 }
1251
1252 hash_position = v->hash_start;
1253 for (i = v->levels - 1; i >= 0; i--) {
1254 sector_t s;
1255 v->hash_level_block[i] = hash_position;
1256 s = (v->data_blocks + ((sector_t)1 << ((i + 1) * v->hash_per_block_bits)) - 1)
1257 >> ((i + 1) * v->hash_per_block_bits);
1258 if (hash_position + s < hash_position) {
1259 ti->error = "Hash device offset overflow";
1260 r = -E2BIG;
1261 goto bad;
1262 }
1263 hash_position += s;
1264 }
1265 v->hash_blocks = hash_position;
1266
1267 v->bufio = dm_bufio_client_create(v->hash_dev->bdev,
1268 1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux),
1269 dm_bufio_alloc_callback, NULL);
1270 if (IS_ERR(v->bufio)) {
1271 ti->error = "Cannot initialize dm-bufio";
1272 r = PTR_ERR(v->bufio);
1273 v->bufio = NULL;
1274 goto bad;
1275 }
1276
1277 if (dm_bufio_get_device_size(v->bufio) < v->hash_blocks) {
1278 ti->error = "Hash device is too small";
1279 r = -E2BIG;
1280 goto bad;
1281 }
1282
1283
1284 v->verify_wq = alloc_workqueue("kverityd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND, num_online_cpus());
1285 if (!v->verify_wq) {
1286 ti->error = "Cannot allocate workqueue";
1287 r = -ENOMEM;
1288 goto bad;
1289 }
1290
1291 ti->per_io_data_size = sizeof(struct dm_verity_io) +
1292 v->ahash_reqsize + v->digest_size * 2;
1293
1294 r = verity_fec_ctr(v);
1295 if (r)
1296 goto bad;
1297
1298 ti->per_io_data_size = roundup(ti->per_io_data_size,
1299 __alignof__(struct dm_verity_io));
1300
1301 verity_verify_sig_opts_cleanup(&verify_args);
1302
1303 return 0;
1304
1305bad:
1306
1307 verity_verify_sig_opts_cleanup(&verify_args);
1308 verity_dtr(ti);
1309
1310 return r;
1311}
1312
1313static struct target_type verity_target = {
1314 .name = "verity",
1315 .version = {1, 8, 0},
1316 .module = THIS_MODULE,
1317 .ctr = verity_ctr,
1318 .dtr = verity_dtr,
1319 .map = verity_map,
1320 .status = verity_status,
1321 .prepare_ioctl = verity_prepare_ioctl,
1322 .iterate_devices = verity_iterate_devices,
1323 .io_hints = verity_io_hints,
1324};
1325
1326static int __init dm_verity_init(void)
1327{
1328 int r;
1329
1330 r = dm_register_target(&verity_target);
1331 if (r < 0)
1332 DMERR("register failed %d", r);
1333
1334 return r;
1335}
1336
1337static void __exit dm_verity_exit(void)
1338{
1339 dm_unregister_target(&verity_target);
1340}
1341
1342module_init(dm_verity_init);
1343module_exit(dm_verity_exit);
1344
1345MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>");
1346MODULE_AUTHOR("Mandeep Baines <msb@chromium.org>");
1347MODULE_AUTHOR("Will Drewry <wad@chromium.org>");
1348MODULE_DESCRIPTION(DM_NAME " target for transparent disk integrity checking");
1349MODULE_LICENSE("GPL");
1350