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ffa39380 ST |
1 | /* |
2 | * Copyright (C) 2012 Red Hat, Inc. | |
3 | * Copyright (C) 2015 Google, Inc. | |
4 | * | |
5 | * Author: Mikulas Patocka <mpatocka@redhat.com> | |
6 | * | |
7 | * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors | |
8 | * | |
9 | * This file is released under the GPLv2. | |
10 | */ | |
11 | ||
12 | #ifndef DM_VERITY_H | |
13 | #define DM_VERITY_H | |
14 | ||
15 | #include "dm-bufio.h" | |
16 | #include <linux/device-mapper.h> | |
17 | #include <crypto/hash.h> | |
18 | ||
19 | #define DM_VERITY_MAX_LEVELS 63 | |
20 | ||
21 | enum verity_mode { | |
22 | DM_VERITY_MODE_EIO, | |
23 | DM_VERITY_MODE_LOGGING, | |
24 | DM_VERITY_MODE_RESTART | |
25 | }; | |
26 | ||
27 | enum verity_block_type { | |
28 | DM_VERITY_BLOCK_TYPE_DATA, | |
29 | DM_VERITY_BLOCK_TYPE_METADATA | |
30 | }; | |
31 | ||
a739ff3f ST |
32 | struct dm_verity_fec; |
33 | ||
ffa39380 ST |
34 | struct dm_verity { |
35 | struct dm_dev *data_dev; | |
36 | struct dm_dev *hash_dev; | |
37 | struct dm_target *ti; | |
38 | struct dm_bufio_client *bufio; | |
39 | char *alg_name; | |
40 | struct crypto_shash *tfm; | |
41 | u8 *root_digest; /* digest of the root block */ | |
42 | u8 *salt; /* salt: its size is salt_size */ | |
0cc37c2d | 43 | u8 *zero_digest; /* digest for a zero block */ |
ffa39380 ST |
44 | unsigned salt_size; |
45 | sector_t data_start; /* data offset in 512-byte sectors */ | |
46 | sector_t hash_start; /* hash start in blocks */ | |
47 | sector_t data_blocks; /* the number of data blocks */ | |
48 | sector_t hash_blocks; /* the number of hash blocks */ | |
49 | unsigned char data_dev_block_bits; /* log2(data blocksize) */ | |
50 | unsigned char hash_dev_block_bits; /* log2(hash blocksize) */ | |
51 | unsigned char hash_per_block_bits; /* log2(hashes in hash block) */ | |
52 | unsigned char levels; /* the number of tree levels */ | |
53 | unsigned char version; | |
54 | unsigned digest_size; /* digest size for the current hash algorithm */ | |
55 | unsigned shash_descsize;/* the size of temporary space for crypto */ | |
56 | int hash_failed; /* set to 1 if hash of any block failed */ | |
57 | enum verity_mode mode; /* mode for handling verification errors */ | |
58 | unsigned corrupted_errs;/* Number of errors for corrupted blocks */ | |
59 | ||
60 | struct workqueue_struct *verify_wq; | |
61 | ||
62 | /* starting blocks for each tree level. 0 is the lowest level. */ | |
63 | sector_t hash_level_block[DM_VERITY_MAX_LEVELS]; | |
a739ff3f ST |
64 | |
65 | struct dm_verity_fec *fec; /* forward error correction */ | |
ffa39380 ST |
66 | }; |
67 | ||
68 | struct dm_verity_io { | |
69 | struct dm_verity *v; | |
70 | ||
71 | /* original value of bio->bi_end_io */ | |
72 | bio_end_io_t *orig_bi_end_io; | |
73 | ||
74 | sector_t block; | |
75 | unsigned n_blocks; | |
76 | ||
77 | struct bvec_iter iter; | |
78 | ||
79 | struct work_struct work; | |
80 | ||
81 | /* | |
82 | * Three variably-size fields follow this struct: | |
83 | * | |
84 | * u8 hash_desc[v->shash_descsize]; | |
85 | * u8 real_digest[v->digest_size]; | |
86 | * u8 want_digest[v->digest_size]; | |
87 | * | |
88 | * To access them use: verity_io_hash_desc(), verity_io_real_digest() | |
89 | * and verity_io_want_digest(). | |
90 | */ | |
91 | }; | |
92 | ||
93 | static inline struct shash_desc *verity_io_hash_desc(struct dm_verity *v, | |
94 | struct dm_verity_io *io) | |
95 | { | |
96 | return (struct shash_desc *)(io + 1); | |
97 | } | |
98 | ||
99 | static inline u8 *verity_io_real_digest(struct dm_verity *v, | |
100 | struct dm_verity_io *io) | |
101 | { | |
102 | return (u8 *)(io + 1) + v->shash_descsize; | |
103 | } | |
104 | ||
105 | static inline u8 *verity_io_want_digest(struct dm_verity *v, | |
106 | struct dm_verity_io *io) | |
107 | { | |
108 | return (u8 *)(io + 1) + v->shash_descsize + v->digest_size; | |
109 | } | |
110 | ||
a739ff3f ST |
111 | static inline u8 *verity_io_digest_end(struct dm_verity *v, |
112 | struct dm_verity_io *io) | |
113 | { | |
114 | return verity_io_want_digest(v, io) + v->digest_size; | |
115 | } | |
116 | ||
bb4d73ac ST |
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)); | |
122 | ||
ffa39380 ST |
123 | extern int verity_hash(struct dm_verity *v, struct shash_desc *desc, |
124 | const u8 *data, size_t len, u8 *digest); | |
125 | ||
126 | extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, | |
0cc37c2d | 127 | sector_t block, u8 *digest, bool *is_zero); |
ffa39380 ST |
128 | |
129 | #endif /* DM_VERITY_H */ |