1 /* SPDX-License-Identifier: GPL-2.0-only */
3 * Copyright (C) 2012 Red Hat, Inc.
4 * Copyright (C) 2015 Google, Inc.
6 * Author: Mikulas Patocka <mpatocka@redhat.com>
8 * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors
14 #include <linux/dm-bufio.h>
15 #include <linux/device-mapper.h>
16 #include <crypto/hash.h>
18 #define DM_VERITY_MAX_LEVELS 63
22 DM_VERITY_MODE_LOGGING,
23 DM_VERITY_MODE_RESTART
26 enum verity_block_type {
27 DM_VERITY_BLOCK_TYPE_DATA,
28 DM_VERITY_BLOCK_TYPE_METADATA
34 struct dm_dev *data_dev;
35 struct dm_dev *hash_dev;
37 struct dm_bufio_client *bufio;
39 struct crypto_ahash *tfm;
40 u8 *root_digest; /* digest of the root block */
41 u8 *salt; /* salt: its size is salt_size */
42 u8 *zero_digest; /* digest for a zero block */
44 sector_t data_start; /* data offset in 512-byte sectors */
45 sector_t hash_start; /* hash start in blocks */
46 sector_t data_blocks; /* the number of data blocks */
47 sector_t hash_blocks; /* the number of hash blocks */
48 unsigned char data_dev_block_bits; /* log2(data blocksize) */
49 unsigned char hash_dev_block_bits; /* log2(hash blocksize) */
50 unsigned char hash_per_block_bits; /* log2(hashes in hash block) */
51 unsigned char levels; /* the number of tree levels */
52 unsigned char version;
53 unsigned digest_size; /* digest size for the current hash algorithm */
54 unsigned int ahash_reqsize;/* the size of temporary space for crypto */
55 int hash_failed; /* set to 1 if hash of any block failed */
56 enum verity_mode mode; /* mode for handling verification errors */
57 unsigned corrupted_errs;/* Number of errors for corrupted blocks */
59 struct workqueue_struct *verify_wq;
61 /* starting blocks for each tree level. 0 is the lowest level. */
62 sector_t hash_level_block[DM_VERITY_MAX_LEVELS];
64 struct dm_verity_fec *fec; /* forward error correction */
65 unsigned long *validated_blocks; /* bitset blocks validated */
71 /* original value of bio->bi_end_io */
72 bio_end_io_t *orig_bi_end_io;
77 struct bvec_iter iter;
79 struct work_struct work;
82 * Three variably-size fields follow this struct:
84 * u8 hash_req[v->ahash_reqsize];
85 * u8 real_digest[v->digest_size];
86 * u8 want_digest[v->digest_size];
88 * To access them use: verity_io_hash_req(), verity_io_real_digest()
89 * and verity_io_want_digest().
93 static inline struct ahash_request *verity_io_hash_req(struct dm_verity *v,
94 struct dm_verity_io *io)
96 return (struct ahash_request *)(io + 1);
99 static inline u8 *verity_io_real_digest(struct dm_verity *v,
100 struct dm_verity_io *io)
102 return (u8 *)(io + 1) + v->ahash_reqsize;
105 static inline u8 *verity_io_want_digest(struct dm_verity *v,
106 struct dm_verity_io *io)
108 return (u8 *)(io + 1) + v->ahash_reqsize + v->digest_size;
111 static inline u8 *verity_io_digest_end(struct dm_verity *v,
112 struct dm_verity_io *io)
114 return verity_io_want_digest(v, io) + v->digest_size;
117 extern int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
118 struct bvec_iter *iter,
119 int (*process)(struct dm_verity *v,
120 struct dm_verity_io *io,
121 u8 *data, size_t len));
123 extern int verity_hash(struct dm_verity *v, struct ahash_request *req,
124 const u8 *data, size_t len, u8 *digest);
126 extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
127 sector_t block, u8 *digest, bool *is_zero);
129 #endif /* DM_VERITY_H */