2 * Copyright (C) 2012 Red Hat, Inc.
4 * Author: Mikulas Patocka <mpatocka@redhat.com>
6 * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors
8 * This file is released under the GPLv2.
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
17 #include "dm-verity.h"
18 #include "dm-verity-fec.h"
20 #include <linux/module.h>
21 #include <linux/reboot.h>
23 #define DM_MSG_PREFIX "verity"
25 #define DM_VERITY_ENV_LENGTH 42
26 #define DM_VERITY_ENV_VAR_NAME "DM_VERITY_ERR_BLOCK_NR"
28 #define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144
30 #define DM_VERITY_MAX_CORRUPTED_ERRS 100
32 #define DM_VERITY_OPT_LOGGING "ignore_corruption"
33 #define DM_VERITY_OPT_RESTART "restart_on_corruption"
34 #define DM_VERITY_OPT_IGN_ZEROES "ignore_zero_blocks"
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);
96 * Callback function for asynchrnous crypto API completion notification
98 static void verity_op_done(struct crypto_async_request *base, int err)
100 struct verity_result *res = (struct verity_result *)base->data;
102 if (err == -EINPROGRESS)
106 complete(&res->completion);
110 * Wait for async crypto API callback
112 static inline int verity_complete_op(struct verity_result *res, int ret)
120 ret = wait_for_completion_interruptible(&res->completion);
123 reinit_completion(&res->completion);
127 DMERR("verity_wait_hash: crypto op submission failed: %d", ret);
130 if (unlikely(ret < 0))
131 DMERR("verity_wait_hash: crypto op failed: %d", ret);
136 static int verity_hash_update(struct dm_verity *v, struct ahash_request *req,
137 const u8 *data, size_t len,
138 struct verity_result *res)
140 struct scatterlist sg;
142 sg_init_one(&sg, data, len);
143 ahash_request_set_crypt(req, &sg, NULL, len);
145 return verity_complete_op(res, crypto_ahash_update(req));
149 * Wrapper for crypto_ahash_init, which handles verity salting.
151 static int verity_hash_init(struct dm_verity *v, struct ahash_request *req,
152 struct verity_result *res)
156 ahash_request_set_tfm(req, v->tfm);
157 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP |
158 CRYPTO_TFM_REQ_MAY_BACKLOG,
159 verity_op_done, (void *)res);
160 init_completion(&res->completion);
162 r = verity_complete_op(res, crypto_ahash_init(req));
164 if (unlikely(r < 0)) {
165 DMERR("crypto_ahash_init failed: %d", r);
169 if (likely(v->version >= 1))
170 r = verity_hash_update(v, req, v->salt, v->salt_size, res);
175 static int verity_hash_final(struct dm_verity *v, struct ahash_request *req,
176 u8 *digest, struct verity_result *res)
180 if (unlikely(!v->version)) {
181 r = verity_hash_update(v, req, v->salt, v->salt_size, res);
184 DMERR("verity_hash_final failed updating salt: %d", r);
189 ahash_request_set_crypt(req, NULL, digest, 0);
190 r = verity_complete_op(res, crypto_ahash_final(req));
195 int verity_hash(struct dm_verity *v, struct ahash_request *req,
196 const u8 *data, size_t len, u8 *digest)
199 struct verity_result res;
201 r = verity_hash_init(v, req, &res);
205 r = verity_hash_update(v, req, data, len, &res);
209 r = verity_hash_final(v, req, digest, &res);
215 static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level,
216 sector_t *hash_block, unsigned *offset)
218 sector_t position = verity_position_at_level(v, block, level);
221 *hash_block = v->hash_level_block[level] + (position >> v->hash_per_block_bits);
226 idx = position & ((1 << v->hash_per_block_bits) - 1);
228 *offset = idx * v->digest_size;
230 *offset = idx << (v->hash_dev_block_bits - v->hash_per_block_bits);
234 * Handle verification errors.
236 static int verity_handle_err(struct dm_verity *v, enum verity_block_type type,
237 unsigned long long block)
239 char verity_env[DM_VERITY_ENV_LENGTH];
240 char *envp[] = { verity_env, NULL };
241 const char *type_str = "";
242 struct mapped_device *md = dm_table_get_md(v->ti->table);
244 /* Corruption should be visible in device status in all modes */
247 if (v->corrupted_errs >= DM_VERITY_MAX_CORRUPTED_ERRS)
253 case DM_VERITY_BLOCK_TYPE_DATA:
256 case DM_VERITY_BLOCK_TYPE_METADATA:
257 type_str = "metadata";
263 DMERR("%s: %s block %llu is corrupted", v->data_dev->name, type_str,
266 if (v->corrupted_errs == DM_VERITY_MAX_CORRUPTED_ERRS)
267 DMERR("%s: reached maximum errors", v->data_dev->name);
269 snprintf(verity_env, DM_VERITY_ENV_LENGTH, "%s=%d,%llu",
270 DM_VERITY_ENV_VAR_NAME, type, block);
272 kobject_uevent_env(&disk_to_dev(dm_disk(md))->kobj, KOBJ_CHANGE, envp);
275 if (v->mode == DM_VERITY_MODE_LOGGING)
278 if (v->mode == DM_VERITY_MODE_RESTART)
279 kernel_restart("dm-verity device corrupted");
285 * Verify hash of a metadata block pertaining to the specified data block
286 * ("block" argument) at a specified level ("level" argument).
288 * On successful return, verity_io_want_digest(v, io) contains the hash value
289 * for a lower tree level or for the data block (if we're at the lowest level).
291 * If "skip_unverified" is true, unverified buffer is skipped and 1 is returned.
292 * If "skip_unverified" is false, unverified buffer is hashed and verified
293 * against current value of verity_io_want_digest(v, io).
295 static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
296 sector_t block, int level, bool skip_unverified,
299 struct dm_buffer *buf;
300 struct buffer_aux *aux;
306 verity_hash_at_level(v, block, level, &hash_block, &offset);
308 data = dm_bufio_read(v->bufio, hash_block, &buf);
310 return PTR_ERR(data);
312 aux = dm_bufio_get_aux_data(buf);
314 if (!aux->hash_verified) {
315 if (skip_unverified) {
320 r = verity_hash(v, verity_io_hash_req(v, io),
321 data, 1 << v->hash_dev_block_bits,
322 verity_io_real_digest(v, io));
326 if (likely(memcmp(verity_io_real_digest(v, io), want_digest,
327 v->digest_size) == 0))
328 aux->hash_verified = 1;
329 else if (verity_fec_decode(v, io,
330 DM_VERITY_BLOCK_TYPE_METADATA,
331 hash_block, data, NULL) == 0)
332 aux->hash_verified = 1;
333 else if (verity_handle_err(v,
334 DM_VERITY_BLOCK_TYPE_METADATA,
342 memcpy(want_digest, data, v->digest_size);
346 dm_bufio_release(buf);
351 * Find a hash for a given block, write it to digest and verify the integrity
352 * of the hash tree if necessary.
354 int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
355 sector_t block, u8 *digest, bool *is_zero)
359 if (likely(v->levels)) {
361 * First, we try to get the requested hash for
362 * the current block. If the hash block itself is
363 * verified, zero is returned. If it isn't, this
364 * function returns 1 and we fall back to whole
365 * chain verification.
367 r = verity_verify_level(v, io, block, 0, true, digest);
372 memcpy(digest, v->root_digest, v->digest_size);
374 for (i = v->levels - 1; i >= 0; i--) {
375 r = verity_verify_level(v, io, block, i, false, digest);
380 if (!r && v->zero_digest)
381 *is_zero = !memcmp(v->zero_digest, digest, v->digest_size);
389 * Calculates the digest for the given bio
391 int verity_for_io_block(struct dm_verity *v, struct dm_verity_io *io,
392 struct bvec_iter *iter, struct verity_result *res)
394 unsigned int todo = 1 << v->data_dev_block_bits;
395 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
396 struct scatterlist sg;
397 struct ahash_request *req = verity_io_hash_req(v, io);
402 struct bio_vec bv = bio_iter_iovec(bio, *iter);
404 sg_init_table(&sg, 1);
408 if (likely(len >= todo))
411 * Operating on a single page at a time looks suboptimal
412 * until you consider the typical block size is 4,096B.
413 * Going through this loops twice should be very rare.
415 sg_set_page(&sg, bv.bv_page, len, bv.bv_offset);
416 ahash_request_set_crypt(req, &sg, NULL, len);
417 r = verity_complete_op(res, crypto_ahash_update(req));
419 if (unlikely(r < 0)) {
420 DMERR("verity_for_io_block crypto op failed: %d", r);
424 bio_advance_iter(bio, iter, len);
432 * Calls function process for 1 << v->data_dev_block_bits bytes in the bio_vec
433 * starting from iter.
435 int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
436 struct bvec_iter *iter,
437 int (*process)(struct dm_verity *v,
438 struct dm_verity_io *io, u8 *data,
441 unsigned todo = 1 << v->data_dev_block_bits;
442 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
448 struct bio_vec bv = bio_iter_iovec(bio, *iter);
450 page = kmap_atomic(bv.bv_page);
453 if (likely(len >= todo))
456 r = process(v, io, page + bv.bv_offset, len);
462 bio_advance_iter(bio, iter, len);
469 static int verity_bv_zero(struct dm_verity *v, struct dm_verity_io *io,
470 u8 *data, size_t len)
472 memset(data, 0, len);
477 * Verify one "dm_verity_io" structure.
479 static int verity_verify_io(struct dm_verity_io *io)
482 struct dm_verity *v = io->v;
483 struct bvec_iter start;
485 struct verity_result res;
487 for (b = 0; b < io->n_blocks; b++) {
489 struct ahash_request *req = verity_io_hash_req(v, io);
491 r = verity_hash_for_block(v, io, io->block + b,
492 verity_io_want_digest(v, io),
499 * If we expect a zero block, don't validate, just
502 r = verity_for_bv_block(v, io, &io->iter,
510 r = verity_hash_init(v, req, &res);
515 r = verity_for_io_block(v, io, &io->iter, &res);
519 r = verity_hash_final(v, req, verity_io_real_digest(v, io),
524 if (likely(memcmp(verity_io_real_digest(v, io),
525 verity_io_want_digest(v, io), v->digest_size) == 0))
527 else if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_DATA,
528 io->block + b, NULL, &start) == 0)
530 else if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA,
539 * End one "io" structure with a given error.
541 static void verity_finish_io(struct dm_verity_io *io, int error)
543 struct dm_verity *v = io->v;
544 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
546 bio->bi_end_io = io->orig_bi_end_io;
547 bio->bi_error = error;
549 verity_fec_finish_io(io);
554 static void verity_work(struct work_struct *w)
556 struct dm_verity_io *io = container_of(w, struct dm_verity_io, work);
558 verity_finish_io(io, verity_verify_io(io));
561 static void verity_end_io(struct bio *bio)
563 struct dm_verity_io *io = bio->bi_private;
565 if (bio->bi_error && !verity_fec_is_enabled(io->v)) {
566 verity_finish_io(io, bio->bi_error);
570 INIT_WORK(&io->work, verity_work);
571 queue_work(io->v->verify_wq, &io->work);
575 * Prefetch buffers for the specified io.
576 * The root buffer is not prefetched, it is assumed that it will be cached
579 static void verity_prefetch_io(struct work_struct *work)
581 struct dm_verity_prefetch_work *pw =
582 container_of(work, struct dm_verity_prefetch_work, work);
583 struct dm_verity *v = pw->v;
586 for (i = v->levels - 2; i >= 0; i--) {
587 sector_t hash_block_start;
588 sector_t hash_block_end;
589 verity_hash_at_level(v, pw->block, i, &hash_block_start, NULL);
590 verity_hash_at_level(v, pw->block + pw->n_blocks - 1, i, &hash_block_end, NULL);
592 unsigned cluster = ACCESS_ONCE(dm_verity_prefetch_cluster);
594 cluster >>= v->data_dev_block_bits;
595 if (unlikely(!cluster))
596 goto no_prefetch_cluster;
598 if (unlikely(cluster & (cluster - 1)))
599 cluster = 1 << __fls(cluster);
601 hash_block_start &= ~(sector_t)(cluster - 1);
602 hash_block_end |= cluster - 1;
603 if (unlikely(hash_block_end >= v->hash_blocks))
604 hash_block_end = v->hash_blocks - 1;
607 dm_bufio_prefetch(v->bufio, hash_block_start,
608 hash_block_end - hash_block_start + 1);
614 static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io)
616 struct dm_verity_prefetch_work *pw;
618 pw = kmalloc(sizeof(struct dm_verity_prefetch_work),
619 GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
624 INIT_WORK(&pw->work, verity_prefetch_io);
626 pw->block = io->block;
627 pw->n_blocks = io->n_blocks;
628 queue_work(v->verify_wq, &pw->work);
632 * Bio map function. It allocates dm_verity_io structure and bio vector and
633 * fills them. Then it issues prefetches and the I/O.
635 static int verity_map(struct dm_target *ti, struct bio *bio)
637 struct dm_verity *v = ti->private;
638 struct dm_verity_io *io;
640 bio->bi_bdev = v->data_dev->bdev;
641 bio->bi_iter.bi_sector = verity_map_sector(v, bio->bi_iter.bi_sector);
643 if (((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) &
644 ((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) {
645 DMERR_LIMIT("unaligned io");
649 if (bio_end_sector(bio) >>
650 (v->data_dev_block_bits - SECTOR_SHIFT) > v->data_blocks) {
651 DMERR_LIMIT("io out of range");
655 if (bio_data_dir(bio) == WRITE)
658 io = dm_per_bio_data(bio, ti->per_io_data_size);
660 io->orig_bi_end_io = bio->bi_end_io;
661 io->block = bio->bi_iter.bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT);
662 io->n_blocks = bio->bi_iter.bi_size >> v->data_dev_block_bits;
664 bio->bi_end_io = verity_end_io;
665 bio->bi_private = io;
666 io->iter = bio->bi_iter;
668 verity_fec_init_io(io);
670 verity_submit_prefetch(v, io);
672 generic_make_request(bio);
674 return DM_MAPIO_SUBMITTED;
678 * Status: V (valid) or C (corruption found)
680 static void verity_status(struct dm_target *ti, status_type_t type,
681 unsigned status_flags, char *result, unsigned maxlen)
683 struct dm_verity *v = ti->private;
689 case STATUSTYPE_INFO:
690 DMEMIT("%c", v->hash_failed ? 'C' : 'V');
692 case STATUSTYPE_TABLE:
693 DMEMIT("%u %s %s %u %u %llu %llu %s ",
697 1 << v->data_dev_block_bits,
698 1 << v->hash_dev_block_bits,
699 (unsigned long long)v->data_blocks,
700 (unsigned long long)v->hash_start,
703 for (x = 0; x < v->digest_size; x++)
704 DMEMIT("%02x", v->root_digest[x]);
709 for (x = 0; x < v->salt_size; x++)
710 DMEMIT("%02x", v->salt[x]);
711 if (v->mode != DM_VERITY_MODE_EIO)
713 if (verity_fec_is_enabled(v))
714 args += DM_VERITY_OPTS_FEC;
720 if (v->mode != DM_VERITY_MODE_EIO) {
723 case DM_VERITY_MODE_LOGGING:
724 DMEMIT(DM_VERITY_OPT_LOGGING);
726 case DM_VERITY_MODE_RESTART:
727 DMEMIT(DM_VERITY_OPT_RESTART);
734 DMEMIT(" " DM_VERITY_OPT_IGN_ZEROES);
735 sz = verity_fec_status_table(v, sz, result, maxlen);
740 static int verity_prepare_ioctl(struct dm_target *ti,
741 struct block_device **bdev, fmode_t *mode)
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);
785 kfree(v->root_digest);
786 kfree(v->zero_digest);
789 crypto_free_ahash(v->tfm);
794 dm_put_device(ti, v->hash_dev);
797 dm_put_device(ti, v->data_dev);
804 static int verity_alloc_zero_digest(struct dm_verity *v)
807 struct ahash_request *req;
810 v->zero_digest = kmalloc(v->digest_size, GFP_KERNEL);
815 req = kmalloc(v->ahash_reqsize, GFP_KERNEL);
818 return r; /* verity_dtr will free zero_digest */
820 zero_data = kzalloc(1 << v->data_dev_block_bits, GFP_KERNEL);
825 r = verity_hash(v, req, zero_data, 1 << v->data_dev_block_bits,
835 static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v)
839 struct dm_target *ti = v->ti;
840 const char *arg_name;
842 static struct dm_arg _args[] = {
843 {0, DM_VERITY_OPTS_MAX, "Invalid number of feature args"},
846 r = dm_read_arg_group(_args, as, &argc, &ti->error);
854 arg_name = dm_shift_arg(as);
857 if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING)) {
858 v->mode = DM_VERITY_MODE_LOGGING;
861 } else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART)) {
862 v->mode = DM_VERITY_MODE_RESTART;
865 } else if (!strcasecmp(arg_name, DM_VERITY_OPT_IGN_ZEROES)) {
866 r = verity_alloc_zero_digest(v);
868 ti->error = "Cannot allocate zero digest";
873 } else if (verity_is_fec_opt_arg(arg_name)) {
874 r = verity_fec_parse_opt_args(as, v, &argc, arg_name);
880 ti->error = "Unrecognized verity feature request";
882 } while (argc && !r);
889 * <version> The current format is version 1.
890 * Vsn 0 is compatible with original Chromium OS releases.
895 * <the number of data blocks>
899 * <salt> Hex string or "-" if no salt.
901 static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
904 struct dm_arg_set as;
906 unsigned long long num_ll;
909 sector_t hash_position;
912 v = kzalloc(sizeof(struct dm_verity), GFP_KERNEL);
914 ti->error = "Cannot allocate verity structure";
920 r = verity_fec_ctr_alloc(v);
924 if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) {
925 ti->error = "Device must be readonly";
931 ti->error = "Not enough arguments";
936 if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 ||
938 ti->error = "Invalid version";
944 r = dm_get_device(ti, argv[1], FMODE_READ, &v->data_dev);
946 ti->error = "Data device lookup failed";
950 r = dm_get_device(ti, argv[2], FMODE_READ, &v->hash_dev);
952 ti->error = "Hash device lookup failed";
956 if (sscanf(argv[3], "%u%c", &num, &dummy) != 1 ||
957 !num || (num & (num - 1)) ||
958 num < bdev_logical_block_size(v->data_dev->bdev) ||
960 ti->error = "Invalid data device block size";
964 v->data_dev_block_bits = __ffs(num);
966 if (sscanf(argv[4], "%u%c", &num, &dummy) != 1 ||
967 !num || (num & (num - 1)) ||
968 num < bdev_logical_block_size(v->hash_dev->bdev) ||
970 ti->error = "Invalid hash device block size";
974 v->hash_dev_block_bits = __ffs(num);
976 if (sscanf(argv[5], "%llu%c", &num_ll, &dummy) != 1 ||
977 (sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT))
978 >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll) {
979 ti->error = "Invalid data blocks";
983 v->data_blocks = num_ll;
985 if (ti->len > (v->data_blocks << (v->data_dev_block_bits - SECTOR_SHIFT))) {
986 ti->error = "Data device is too small";
991 if (sscanf(argv[6], "%llu%c", &num_ll, &dummy) != 1 ||
992 (sector_t)(num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT))
993 >> (v->hash_dev_block_bits - SECTOR_SHIFT) != num_ll) {
994 ti->error = "Invalid hash start";
998 v->hash_start = num_ll;
1000 v->alg_name = kstrdup(argv[7], GFP_KERNEL);
1002 ti->error = "Cannot allocate algorithm name";
1007 v->tfm = crypto_alloc_ahash(v->alg_name, 0, 0);
1008 if (IS_ERR(v->tfm)) {
1009 ti->error = "Cannot initialize hash function";
1010 r = PTR_ERR(v->tfm);
1014 v->digest_size = crypto_ahash_digestsize(v->tfm);
1015 if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) {
1016 ti->error = "Digest size too big";
1020 v->ahash_reqsize = sizeof(struct ahash_request) +
1021 crypto_ahash_reqsize(v->tfm);
1023 v->root_digest = kmalloc(v->digest_size, GFP_KERNEL);
1024 if (!v->root_digest) {
1025 ti->error = "Cannot allocate root digest";
1029 if (strlen(argv[8]) != v->digest_size * 2 ||
1030 hex2bin(v->root_digest, argv[8], v->digest_size)) {
1031 ti->error = "Invalid root digest";
1036 if (strcmp(argv[9], "-")) {
1037 v->salt_size = strlen(argv[9]) / 2;
1038 v->salt = kmalloc(v->salt_size, GFP_KERNEL);
1040 ti->error = "Cannot allocate salt";
1044 if (strlen(argv[9]) != v->salt_size * 2 ||
1045 hex2bin(v->salt, argv[9], v->salt_size)) {
1046 ti->error = "Invalid salt";
1055 /* Optional parameters */
1060 r = verity_parse_opt_args(&as, v);
1065 v->hash_per_block_bits =
1066 __fls((1 << v->hash_dev_block_bits) / v->digest_size);
1070 while (v->hash_per_block_bits * v->levels < 64 &&
1071 (unsigned long long)(v->data_blocks - 1) >>
1072 (v->hash_per_block_bits * v->levels))
1075 if (v->levels > DM_VERITY_MAX_LEVELS) {
1076 ti->error = "Too many tree levels";
1081 hash_position = v->hash_start;
1082 for (i = v->levels - 1; i >= 0; i--) {
1084 v->hash_level_block[i] = hash_position;
1085 s = (v->data_blocks + ((sector_t)1 << ((i + 1) * v->hash_per_block_bits)) - 1)
1086 >> ((i + 1) * v->hash_per_block_bits);
1087 if (hash_position + s < hash_position) {
1088 ti->error = "Hash device offset overflow";
1094 v->hash_blocks = hash_position;
1096 v->bufio = dm_bufio_client_create(v->hash_dev->bdev,
1097 1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux),
1098 dm_bufio_alloc_callback, NULL);
1099 if (IS_ERR(v->bufio)) {
1100 ti->error = "Cannot initialize dm-bufio";
1101 r = PTR_ERR(v->bufio);
1106 if (dm_bufio_get_device_size(v->bufio) < v->hash_blocks) {
1107 ti->error = "Hash device is too small";
1112 /* WQ_UNBOUND greatly improves performance when running on ramdisk */
1113 v->verify_wq = alloc_workqueue("kverityd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND, num_online_cpus());
1114 if (!v->verify_wq) {
1115 ti->error = "Cannot allocate workqueue";
1120 ti->per_io_data_size = sizeof(struct dm_verity_io) +
1121 v->ahash_reqsize + v->digest_size * 2;
1123 r = verity_fec_ctr(v);
1127 ti->per_io_data_size = roundup(ti->per_io_data_size,
1128 __alignof__(struct dm_verity_io));
1138 static struct target_type verity_target = {
1140 .version = {1, 3, 0},
1141 .module = THIS_MODULE,
1145 .status = verity_status,
1146 .prepare_ioctl = verity_prepare_ioctl,
1147 .iterate_devices = verity_iterate_devices,
1148 .io_hints = verity_io_hints,
1151 static int __init dm_verity_init(void)
1155 r = dm_register_target(&verity_target);
1157 DMERR("register failed %d", r);
1162 static void __exit dm_verity_exit(void)
1164 dm_unregister_target(&verity_target);
1167 module_init(dm_verity_init);
1168 module_exit(dm_verity_exit);
1170 MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>");
1171 MODULE_AUTHOR("Mandeep Baines <msb@chromium.org>");
1172 MODULE_AUTHOR("Will Drewry <wad@chromium.org>");
1173 MODULE_DESCRIPTION(DM_NAME " target for transparent disk integrity checking");
1174 MODULE_LICENSE("GPL");