1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2012 Red Hat, Inc.
5 * Author: Mikulas Patocka <mpatocka@redhat.com>
7 * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors
9 * In the file "/sys/module/dm_verity/parameters/prefetch_cluster" you can set
10 * default prefetch value. Data are read in "prefetch_cluster" chunks from the
11 * hash device. Setting this greatly improves performance when data and hash
12 * are on the same disk on different partitions on devices with poor random
16 #include "dm-verity.h"
17 #include "dm-verity-fec.h"
19 #include <linux/module.h>
20 #include <linux/reboot.h>
22 #define DM_MSG_PREFIX "verity"
24 #define DM_VERITY_ENV_LENGTH 42
25 #define DM_VERITY_ENV_VAR_NAME "DM_VERITY_ERR_BLOCK_NR"
27 #define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144
29 #define DM_VERITY_MAX_CORRUPTED_ERRS 100
31 #define DM_VERITY_OPT_LOGGING "ignore_corruption"
32 #define DM_VERITY_OPT_RESTART "restart_on_corruption"
33 #define DM_VERITY_OPT_IGN_ZEROES "ignore_zero_blocks"
34 #define DM_VERITY_OPT_AT_MOST_ONCE "check_at_most_once"
36 #define DM_VERITY_OPTS_MAX (2 + DM_VERITY_OPTS_FEC)
38 static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE;
40 module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR);
42 struct dm_verity_prefetch_work {
43 struct work_struct work;
50 * Auxiliary structure appended to each dm-bufio buffer. If the value
51 * hash_verified is nonzero, hash of the block has been verified.
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.
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.
66 * Initialize struct buffer_aux for a freshly created buffer.
68 static void dm_bufio_alloc_callback(struct dm_buffer *buf)
70 struct buffer_aux *aux = dm_bufio_get_aux_data(buf);
72 aux->hash_verified = 0;
76 * Translate input sector number to the sector number on the target device.
78 static sector_t verity_map_sector(struct dm_verity *v, sector_t bi_sector)
80 return v->data_start + dm_target_offset(v->ti, bi_sector);
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.
89 static sector_t verity_position_at_level(struct dm_verity *v, sector_t block,
92 return block >> (level * v->hash_per_block_bits);
95 static int verity_hash_update(struct dm_verity *v, struct ahash_request *req,
96 const u8 *data, size_t len,
97 struct crypto_wait *wait)
99 struct scatterlist sg;
101 if (likely(!is_vmalloc_addr(data))) {
102 sg_init_one(&sg, data, len);
103 ahash_request_set_crypt(req, &sg, NULL, len);
104 return crypto_wait_req(crypto_ahash_update(req), wait);
108 size_t this_step = min_t(size_t, len, PAGE_SIZE - offset_in_page(data));
109 flush_kernel_vmap_range((void *)data, this_step);
110 sg_init_table(&sg, 1);
111 sg_set_page(&sg, vmalloc_to_page(data), this_step, offset_in_page(data));
112 ahash_request_set_crypt(req, &sg, NULL, this_step);
113 r = crypto_wait_req(crypto_ahash_update(req), wait);
124 * Wrapper for crypto_ahash_init, which handles verity salting.
126 static int verity_hash_init(struct dm_verity *v, struct ahash_request *req,
127 struct crypto_wait *wait)
131 ahash_request_set_tfm(req, v->tfm);
132 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP |
133 CRYPTO_TFM_REQ_MAY_BACKLOG,
134 crypto_req_done, (void *)wait);
135 crypto_init_wait(wait);
137 r = crypto_wait_req(crypto_ahash_init(req), wait);
139 if (unlikely(r < 0)) {
140 DMERR("crypto_ahash_init failed: %d", r);
144 if (likely(v->salt_size && (v->version >= 1)))
145 r = verity_hash_update(v, req, v->salt, v->salt_size, wait);
150 static int verity_hash_final(struct dm_verity *v, struct ahash_request *req,
151 u8 *digest, struct crypto_wait *wait)
155 if (unlikely(v->salt_size && (!v->version))) {
156 r = verity_hash_update(v, req, v->salt, v->salt_size, wait);
159 DMERR("verity_hash_final failed updating salt: %d", r);
164 ahash_request_set_crypt(req, NULL, digest, 0);
165 r = crypto_wait_req(crypto_ahash_final(req), wait);
170 int verity_hash(struct dm_verity *v, struct ahash_request *req,
171 const u8 *data, size_t len, u8 *digest)
174 struct crypto_wait wait;
176 r = verity_hash_init(v, req, &wait);
180 r = verity_hash_update(v, req, data, len, &wait);
184 r = verity_hash_final(v, req, digest, &wait);
190 static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level,
191 sector_t *hash_block, unsigned *offset)
193 sector_t position = verity_position_at_level(v, block, level);
196 *hash_block = v->hash_level_block[level] + (position >> v->hash_per_block_bits);
201 idx = position & ((1 << v->hash_per_block_bits) - 1);
203 *offset = idx * v->digest_size;
205 *offset = idx << (v->hash_dev_block_bits - v->hash_per_block_bits);
209 * Handle verification errors.
211 static int verity_handle_err(struct dm_verity *v, enum verity_block_type type,
212 unsigned long long block)
214 char verity_env[DM_VERITY_ENV_LENGTH];
215 char *envp[] = { verity_env, NULL };
216 const char *type_str = "";
217 struct mapped_device *md = dm_table_get_md(v->ti->table);
219 /* Corruption should be visible in device status in all modes */
222 if (v->corrupted_errs >= DM_VERITY_MAX_CORRUPTED_ERRS)
228 case DM_VERITY_BLOCK_TYPE_DATA:
231 case DM_VERITY_BLOCK_TYPE_METADATA:
232 type_str = "metadata";
238 DMERR_LIMIT("%s: %s block %llu is corrupted", v->data_dev->name,
241 if (v->corrupted_errs == DM_VERITY_MAX_CORRUPTED_ERRS)
242 DMERR("%s: reached maximum errors", v->data_dev->name);
244 snprintf(verity_env, DM_VERITY_ENV_LENGTH, "%s=%d,%llu",
245 DM_VERITY_ENV_VAR_NAME, type, block);
247 kobject_uevent_env(&disk_to_dev(dm_disk(md))->kobj, KOBJ_CHANGE, envp);
250 if (v->mode == DM_VERITY_MODE_LOGGING)
253 if (v->mode == DM_VERITY_MODE_RESTART)
254 kernel_restart("dm-verity device corrupted");
260 * Verify hash of a metadata block pertaining to the specified data block
261 * ("block" argument) at a specified level ("level" argument).
263 * On successful return, verity_io_want_digest(v, io) contains the hash value
264 * for a lower tree level or for the data block (if we're at the lowest level).
266 * If "skip_unverified" is true, unverified buffer is skipped and 1 is returned.
267 * If "skip_unverified" is false, unverified buffer is hashed and verified
268 * against current value of verity_io_want_digest(v, io).
270 static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
271 sector_t block, int level, bool skip_unverified,
274 struct dm_buffer *buf;
275 struct buffer_aux *aux;
281 verity_hash_at_level(v, block, level, &hash_block, &offset);
283 data = dm_bufio_read(v->bufio, hash_block, &buf);
285 return PTR_ERR(data);
287 aux = dm_bufio_get_aux_data(buf);
289 if (!aux->hash_verified) {
290 if (skip_unverified) {
295 r = verity_hash(v, verity_io_hash_req(v, io),
296 data, 1 << v->hash_dev_block_bits,
297 verity_io_real_digest(v, io));
301 if (likely(memcmp(verity_io_real_digest(v, io), want_digest,
302 v->digest_size) == 0))
303 aux->hash_verified = 1;
304 else if (verity_fec_decode(v, io,
305 DM_VERITY_BLOCK_TYPE_METADATA,
306 hash_block, data, NULL) == 0)
307 aux->hash_verified = 1;
308 else if (verity_handle_err(v,
309 DM_VERITY_BLOCK_TYPE_METADATA,
317 memcpy(want_digest, data, v->digest_size);
321 dm_bufio_release(buf);
326 * Find a hash for a given block, write it to digest and verify the integrity
327 * of the hash tree if necessary.
329 int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
330 sector_t block, u8 *digest, bool *is_zero)
334 if (likely(v->levels)) {
336 * First, we try to get the requested hash for
337 * the current block. If the hash block itself is
338 * verified, zero is returned. If it isn't, this
339 * function returns 1 and we fall back to whole
340 * chain verification.
342 r = verity_verify_level(v, io, block, 0, true, digest);
347 memcpy(digest, v->root_digest, v->digest_size);
349 for (i = v->levels - 1; i >= 0; i--) {
350 r = verity_verify_level(v, io, block, i, false, digest);
355 if (!r && v->zero_digest)
356 *is_zero = !memcmp(v->zero_digest, digest, v->digest_size);
364 * Calculates the digest for the given bio
366 static int verity_for_io_block(struct dm_verity *v, struct dm_verity_io *io,
367 struct bvec_iter *iter, struct crypto_wait *wait)
369 unsigned int todo = 1 << v->data_dev_block_bits;
370 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
371 struct scatterlist sg;
372 struct ahash_request *req = verity_io_hash_req(v, io);
377 struct bio_vec bv = bio_iter_iovec(bio, *iter);
379 sg_init_table(&sg, 1);
383 if (likely(len >= todo))
386 * Operating on a single page at a time looks suboptimal
387 * until you consider the typical block size is 4,096B.
388 * Going through this loops twice should be very rare.
390 sg_set_page(&sg, bv.bv_page, len, bv.bv_offset);
391 ahash_request_set_crypt(req, &sg, NULL, len);
392 r = crypto_wait_req(crypto_ahash_update(req), wait);
394 if (unlikely(r < 0)) {
395 DMERR("verity_for_io_block crypto op failed: %d", r);
399 bio_advance_iter(bio, iter, len);
407 * Calls function process for 1 << v->data_dev_block_bits bytes in the bio_vec
408 * starting from iter.
410 int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
411 struct bvec_iter *iter,
412 int (*process)(struct dm_verity *v,
413 struct dm_verity_io *io, u8 *data,
416 unsigned todo = 1 << v->data_dev_block_bits;
417 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
423 struct bio_vec bv = bio_iter_iovec(bio, *iter);
425 page = kmap_atomic(bv.bv_page);
428 if (likely(len >= todo))
431 r = process(v, io, page + bv.bv_offset, len);
437 bio_advance_iter(bio, iter, len);
444 static int verity_bv_zero(struct dm_verity *v, struct dm_verity_io *io,
445 u8 *data, size_t len)
447 memset(data, 0, len);
452 * Moves the bio iter one data block forward.
454 static inline void verity_bv_skip_block(struct dm_verity *v,
455 struct dm_verity_io *io,
456 struct bvec_iter *iter)
458 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
460 bio_advance_iter(bio, iter, 1 << v->data_dev_block_bits);
464 * Verify one "dm_verity_io" structure.
466 static int verity_verify_io(struct dm_verity_io *io)
469 struct dm_verity *v = io->v;
470 struct bvec_iter start;
472 struct crypto_wait wait;
474 for (b = 0; b < io->n_blocks; b++) {
476 sector_t cur_block = io->block + b;
477 struct ahash_request *req = verity_io_hash_req(v, io);
479 if (v->validated_blocks &&
480 likely(test_bit(cur_block, v->validated_blocks))) {
481 verity_bv_skip_block(v, io, &io->iter);
485 r = verity_hash_for_block(v, io, cur_block,
486 verity_io_want_digest(v, io),
493 * If we expect a zero block, don't validate, just
496 r = verity_for_bv_block(v, io, &io->iter,
504 r = verity_hash_init(v, req, &wait);
509 r = verity_for_io_block(v, io, &io->iter, &wait);
513 r = verity_hash_final(v, req, verity_io_real_digest(v, io),
518 if (likely(memcmp(verity_io_real_digest(v, io),
519 verity_io_want_digest(v, io), v->digest_size) == 0)) {
520 if (v->validated_blocks)
521 set_bit(cur_block, v->validated_blocks);
524 else if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_DATA,
525 cur_block, NULL, &start) == 0)
527 else if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA,
536 * End one "io" structure with a given error.
538 static void verity_finish_io(struct dm_verity_io *io, blk_status_t status)
540 struct dm_verity *v = io->v;
541 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
543 bio->bi_end_io = io->orig_bi_end_io;
544 bio->bi_status = status;
546 verity_fec_finish_io(io);
551 static void verity_work(struct work_struct *w)
553 struct dm_verity_io *io = container_of(w, struct dm_verity_io, work);
555 verity_finish_io(io, errno_to_blk_status(verity_verify_io(io)));
558 static void verity_end_io(struct bio *bio)
560 struct dm_verity_io *io = bio->bi_private;
562 if (bio->bi_status && !verity_fec_is_enabled(io->v)) {
563 verity_finish_io(io, bio->bi_status);
567 INIT_WORK(&io->work, verity_work);
568 queue_work(io->v->verify_wq, &io->work);
572 * Prefetch buffers for the specified io.
573 * The root buffer is not prefetched, it is assumed that it will be cached
576 static void verity_prefetch_io(struct work_struct *work)
578 struct dm_verity_prefetch_work *pw =
579 container_of(work, struct dm_verity_prefetch_work, work);
580 struct dm_verity *v = pw->v;
583 for (i = v->levels - 2; i >= 0; i--) {
584 sector_t hash_block_start;
585 sector_t hash_block_end;
586 verity_hash_at_level(v, pw->block, i, &hash_block_start, NULL);
587 verity_hash_at_level(v, pw->block + pw->n_blocks - 1, i, &hash_block_end, NULL);
589 unsigned cluster = READ_ONCE(dm_verity_prefetch_cluster);
591 cluster >>= v->data_dev_block_bits;
592 if (unlikely(!cluster))
593 goto no_prefetch_cluster;
595 if (unlikely(cluster & (cluster - 1)))
596 cluster = 1 << __fls(cluster);
598 hash_block_start &= ~(sector_t)(cluster - 1);
599 hash_block_end |= cluster - 1;
600 if (unlikely(hash_block_end >= v->hash_blocks))
601 hash_block_end = v->hash_blocks - 1;
604 dm_bufio_prefetch(v->bufio, hash_block_start,
605 hash_block_end - hash_block_start + 1);
611 static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io)
613 struct dm_verity_prefetch_work *pw;
615 pw = kmalloc(sizeof(struct dm_verity_prefetch_work),
616 GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
621 INIT_WORK(&pw->work, verity_prefetch_io);
623 pw->block = io->block;
624 pw->n_blocks = io->n_blocks;
625 queue_work(v->verify_wq, &pw->work);
629 * Bio map function. It allocates dm_verity_io structure and bio vector and
630 * fills them. Then it issues prefetches and the I/O.
632 static int verity_map(struct dm_target *ti, struct bio *bio)
634 struct dm_verity *v = ti->private;
635 struct dm_verity_io *io;
637 bio_set_dev(bio, v->data_dev->bdev);
638 bio->bi_iter.bi_sector = verity_map_sector(v, bio->bi_iter.bi_sector);
640 if (((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) &
641 ((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) {
642 DMERR_LIMIT("unaligned io");
643 return DM_MAPIO_KILL;
646 if (bio_end_sector(bio) >>
647 (v->data_dev_block_bits - SECTOR_SHIFT) > v->data_blocks) {
648 DMERR_LIMIT("io out of range");
649 return DM_MAPIO_KILL;
652 if (bio_data_dir(bio) == WRITE)
653 return DM_MAPIO_KILL;
655 io = dm_per_bio_data(bio, ti->per_io_data_size);
657 io->orig_bi_end_io = bio->bi_end_io;
658 io->block = bio->bi_iter.bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT);
659 io->n_blocks = bio->bi_iter.bi_size >> v->data_dev_block_bits;
661 bio->bi_end_io = verity_end_io;
662 bio->bi_private = io;
663 io->iter = bio->bi_iter;
665 verity_fec_init_io(io);
667 verity_submit_prefetch(v, io);
669 generic_make_request(bio);
671 return DM_MAPIO_SUBMITTED;
675 * Status: V (valid) or C (corruption found)
677 static void verity_status(struct dm_target *ti, status_type_t type,
678 unsigned status_flags, char *result, unsigned maxlen)
680 struct dm_verity *v = ti->private;
686 case STATUSTYPE_INFO:
687 DMEMIT("%c", v->hash_failed ? 'C' : 'V');
689 case STATUSTYPE_TABLE:
690 DMEMIT("%u %s %s %u %u %llu %llu %s ",
694 1 << v->data_dev_block_bits,
695 1 << v->hash_dev_block_bits,
696 (unsigned long long)v->data_blocks,
697 (unsigned long long)v->hash_start,
700 for (x = 0; x < v->digest_size; x++)
701 DMEMIT("%02x", v->root_digest[x]);
706 for (x = 0; x < v->salt_size; x++)
707 DMEMIT("%02x", v->salt[x]);
708 if (v->mode != DM_VERITY_MODE_EIO)
710 if (verity_fec_is_enabled(v))
711 args += DM_VERITY_OPTS_FEC;
714 if (v->validated_blocks)
719 if (v->mode != DM_VERITY_MODE_EIO) {
722 case DM_VERITY_MODE_LOGGING:
723 DMEMIT(DM_VERITY_OPT_LOGGING);
725 case DM_VERITY_MODE_RESTART:
726 DMEMIT(DM_VERITY_OPT_RESTART);
733 DMEMIT(" " DM_VERITY_OPT_IGN_ZEROES);
734 if (v->validated_blocks)
735 DMEMIT(" " DM_VERITY_OPT_AT_MOST_ONCE);
736 sz = verity_fec_status_table(v, sz, result, maxlen);
741 static int verity_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
743 struct dm_verity *v = ti->private;
745 *bdev = v->data_dev->bdev;
748 ti->len != i_size_read(v->data_dev->bdev->bd_inode) >> SECTOR_SHIFT)
753 static int verity_iterate_devices(struct dm_target *ti,
754 iterate_devices_callout_fn fn, void *data)
756 struct dm_verity *v = ti->private;
758 return fn(ti, v->data_dev, v->data_start, ti->len, data);
761 static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits)
763 struct dm_verity *v = ti->private;
765 if (limits->logical_block_size < 1 << v->data_dev_block_bits)
766 limits->logical_block_size = 1 << v->data_dev_block_bits;
768 if (limits->physical_block_size < 1 << v->data_dev_block_bits)
769 limits->physical_block_size = 1 << v->data_dev_block_bits;
771 blk_limits_io_min(limits, limits->logical_block_size);
774 static void verity_dtr(struct dm_target *ti)
776 struct dm_verity *v = ti->private;
779 destroy_workqueue(v->verify_wq);
782 dm_bufio_client_destroy(v->bufio);
784 kvfree(v->validated_blocks);
786 kfree(v->root_digest);
787 kfree(v->zero_digest);
790 crypto_free_ahash(v->tfm);
795 dm_put_device(ti, v->hash_dev);
798 dm_put_device(ti, v->data_dev);
805 static int verity_alloc_most_once(struct dm_verity *v)
807 struct dm_target *ti = v->ti;
809 /* the bitset can only handle INT_MAX blocks */
810 if (v->data_blocks > INT_MAX) {
811 ti->error = "device too large to use check_at_most_once";
815 v->validated_blocks = kvcalloc(BITS_TO_LONGS(v->data_blocks),
816 sizeof(unsigned long),
818 if (!v->validated_blocks) {
819 ti->error = "failed to allocate bitset for check_at_most_once";
826 static int verity_alloc_zero_digest(struct dm_verity *v)
829 struct ahash_request *req;
832 v->zero_digest = kmalloc(v->digest_size, GFP_KERNEL);
837 req = kmalloc(v->ahash_reqsize, GFP_KERNEL);
840 return r; /* verity_dtr will free zero_digest */
842 zero_data = kzalloc(1 << v->data_dev_block_bits, GFP_KERNEL);
847 r = verity_hash(v, req, zero_data, 1 << v->data_dev_block_bits,
857 static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v)
861 struct dm_target *ti = v->ti;
862 const char *arg_name;
864 static const struct dm_arg _args[] = {
865 {0, DM_VERITY_OPTS_MAX, "Invalid number of feature args"},
868 r = dm_read_arg_group(_args, as, &argc, &ti->error);
876 arg_name = dm_shift_arg(as);
879 if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING)) {
880 v->mode = DM_VERITY_MODE_LOGGING;
883 } else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART)) {
884 v->mode = DM_VERITY_MODE_RESTART;
887 } else if (!strcasecmp(arg_name, DM_VERITY_OPT_IGN_ZEROES)) {
888 r = verity_alloc_zero_digest(v);
890 ti->error = "Cannot allocate zero digest";
895 } else if (!strcasecmp(arg_name, DM_VERITY_OPT_AT_MOST_ONCE)) {
896 r = verity_alloc_most_once(v);
901 } else if (verity_is_fec_opt_arg(arg_name)) {
902 r = verity_fec_parse_opt_args(as, v, &argc, arg_name);
908 ti->error = "Unrecognized verity feature request";
910 } while (argc && !r);
917 * <version> The current format is version 1.
918 * Vsn 0 is compatible with original Chromium OS releases.
923 * <the number of data blocks>
927 * <salt> Hex string or "-" if no salt.
929 static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
932 struct dm_arg_set as;
934 unsigned long long num_ll;
937 sector_t hash_position;
940 v = kzalloc(sizeof(struct dm_verity), GFP_KERNEL);
942 ti->error = "Cannot allocate verity structure";
948 r = verity_fec_ctr_alloc(v);
952 if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) {
953 ti->error = "Device must be readonly";
959 ti->error = "Not enough arguments";
964 if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 ||
966 ti->error = "Invalid version";
972 r = dm_get_device(ti, argv[1], FMODE_READ, &v->data_dev);
974 ti->error = "Data device lookup failed";
978 r = dm_get_device(ti, argv[2], FMODE_READ, &v->hash_dev);
980 ti->error = "Hash device lookup failed";
984 if (sscanf(argv[3], "%u%c", &num, &dummy) != 1 ||
985 !num || (num & (num - 1)) ||
986 num < bdev_logical_block_size(v->data_dev->bdev) ||
988 ti->error = "Invalid data device block size";
992 v->data_dev_block_bits = __ffs(num);
994 if (sscanf(argv[4], "%u%c", &num, &dummy) != 1 ||
995 !num || (num & (num - 1)) ||
996 num < bdev_logical_block_size(v->hash_dev->bdev) ||
998 ti->error = "Invalid hash device block size";
1002 v->hash_dev_block_bits = __ffs(num);
1004 if (sscanf(argv[5], "%llu%c", &num_ll, &dummy) != 1 ||
1005 (sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT))
1006 >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll) {
1007 ti->error = "Invalid data blocks";
1011 v->data_blocks = num_ll;
1013 if (ti->len > (v->data_blocks << (v->data_dev_block_bits - SECTOR_SHIFT))) {
1014 ti->error = "Data device is too small";
1019 if (sscanf(argv[6], "%llu%c", &num_ll, &dummy) != 1 ||
1020 (sector_t)(num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT))
1021 >> (v->hash_dev_block_bits - SECTOR_SHIFT) != num_ll) {
1022 ti->error = "Invalid hash start";
1026 v->hash_start = num_ll;
1028 v->alg_name = kstrdup(argv[7], GFP_KERNEL);
1030 ti->error = "Cannot allocate algorithm name";
1035 v->tfm = crypto_alloc_ahash(v->alg_name, 0, 0);
1036 if (IS_ERR(v->tfm)) {
1037 ti->error = "Cannot initialize hash function";
1038 r = PTR_ERR(v->tfm);
1044 * dm-verity performance can vary greatly depending on which hash
1045 * algorithm implementation is used. Help people debug performance
1046 * problems by logging the ->cra_driver_name.
1048 DMINFO("%s using implementation \"%s\"", v->alg_name,
1049 crypto_hash_alg_common(v->tfm)->base.cra_driver_name);
1051 v->digest_size = crypto_ahash_digestsize(v->tfm);
1052 if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) {
1053 ti->error = "Digest size too big";
1057 v->ahash_reqsize = sizeof(struct ahash_request) +
1058 crypto_ahash_reqsize(v->tfm);
1060 v->root_digest = kmalloc(v->digest_size, GFP_KERNEL);
1061 if (!v->root_digest) {
1062 ti->error = "Cannot allocate root digest";
1066 if (strlen(argv[8]) != v->digest_size * 2 ||
1067 hex2bin(v->root_digest, argv[8], v->digest_size)) {
1068 ti->error = "Invalid root digest";
1073 if (strcmp(argv[9], "-")) {
1074 v->salt_size = strlen(argv[9]) / 2;
1075 v->salt = kmalloc(v->salt_size, GFP_KERNEL);
1077 ti->error = "Cannot allocate salt";
1081 if (strlen(argv[9]) != v->salt_size * 2 ||
1082 hex2bin(v->salt, argv[9], v->salt_size)) {
1083 ti->error = "Invalid salt";
1092 /* Optional parameters */
1097 r = verity_parse_opt_args(&as, v);
1102 v->hash_per_block_bits =
1103 __fls((1 << v->hash_dev_block_bits) / v->digest_size);
1107 while (v->hash_per_block_bits * v->levels < 64 &&
1108 (unsigned long long)(v->data_blocks - 1) >>
1109 (v->hash_per_block_bits * v->levels))
1112 if (v->levels > DM_VERITY_MAX_LEVELS) {
1113 ti->error = "Too many tree levels";
1118 hash_position = v->hash_start;
1119 for (i = v->levels - 1; i >= 0; i--) {
1121 v->hash_level_block[i] = hash_position;
1122 s = (v->data_blocks + ((sector_t)1 << ((i + 1) * v->hash_per_block_bits)) - 1)
1123 >> ((i + 1) * v->hash_per_block_bits);
1124 if (hash_position + s < hash_position) {
1125 ti->error = "Hash device offset overflow";
1131 v->hash_blocks = hash_position;
1133 v->bufio = dm_bufio_client_create(v->hash_dev->bdev,
1134 1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux),
1135 dm_bufio_alloc_callback, NULL);
1136 if (IS_ERR(v->bufio)) {
1137 ti->error = "Cannot initialize dm-bufio";
1138 r = PTR_ERR(v->bufio);
1143 if (dm_bufio_get_device_size(v->bufio) < v->hash_blocks) {
1144 ti->error = "Hash device is too small";
1149 /* WQ_UNBOUND greatly improves performance when running on ramdisk */
1150 v->verify_wq = alloc_workqueue("kverityd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND, num_online_cpus());
1151 if (!v->verify_wq) {
1152 ti->error = "Cannot allocate workqueue";
1157 ti->per_io_data_size = sizeof(struct dm_verity_io) +
1158 v->ahash_reqsize + v->digest_size * 2;
1160 r = verity_fec_ctr(v);
1164 ti->per_io_data_size = roundup(ti->per_io_data_size,
1165 __alignof__(struct dm_verity_io));
1175 static struct target_type verity_target = {
1177 .version = {1, 4, 0},
1178 .module = THIS_MODULE,
1182 .status = verity_status,
1183 .prepare_ioctl = verity_prepare_ioctl,
1184 .iterate_devices = verity_iterate_devices,
1185 .io_hints = verity_io_hints,
1188 static int __init dm_verity_init(void)
1192 r = dm_register_target(&verity_target);
1194 DMERR("register failed %d", r);
1199 static void __exit dm_verity_exit(void)
1201 dm_unregister_target(&verity_target);
1204 module_init(dm_verity_init);
1205 module_exit(dm_verity_exit);
1207 MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>");
1208 MODULE_AUTHOR("Mandeep Baines <msb@chromium.org>");
1209 MODULE_AUTHOR("Will Drewry <wad@chromium.org>");
1210 MODULE_DESCRIPTION(DM_NAME " target for transparent disk integrity checking");
1211 MODULE_LICENSE("GPL");