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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 | ||
32 | struct dm_verity { | |
33 | struct dm_dev *data_dev; | |
34 | struct dm_dev *hash_dev; | |
35 | struct dm_target *ti; | |
36 | struct dm_bufio_client *bufio; | |
37 | char *alg_name; | |
38 | struct crypto_shash *tfm; | |
39 | u8 *root_digest; /* digest of the root block */ | |
40 | u8 *salt; /* salt: its size is salt_size */ | |
41 | unsigned salt_size; | |
42 | sector_t data_start; /* data offset in 512-byte sectors */ | |
43 | sector_t hash_start; /* hash start in blocks */ | |
44 | sector_t data_blocks; /* the number of data blocks */ | |
45 | sector_t hash_blocks; /* the number of hash blocks */ | |
46 | unsigned char data_dev_block_bits; /* log2(data blocksize) */ | |
47 | unsigned char hash_dev_block_bits; /* log2(hash blocksize) */ | |
48 | unsigned char hash_per_block_bits; /* log2(hashes in hash block) */ | |
49 | unsigned char levels; /* the number of tree levels */ | |
50 | unsigned char version; | |
51 | unsigned digest_size; /* digest size for the current hash algorithm */ | |
52 | unsigned shash_descsize;/* the size of temporary space for crypto */ | |
53 | int hash_failed; /* set to 1 if hash of any block failed */ | |
54 | enum verity_mode mode; /* mode for handling verification errors */ | |
55 | unsigned corrupted_errs;/* Number of errors for corrupted blocks */ | |
56 | ||
57 | struct workqueue_struct *verify_wq; | |
58 | ||
59 | /* starting blocks for each tree level. 0 is the lowest level. */ | |
60 | sector_t hash_level_block[DM_VERITY_MAX_LEVELS]; | |
61 | }; | |
62 | ||
63 | struct dm_verity_io { | |
64 | struct dm_verity *v; | |
65 | ||
66 | /* original value of bio->bi_end_io */ | |
67 | bio_end_io_t *orig_bi_end_io; | |
68 | ||
69 | sector_t block; | |
70 | unsigned n_blocks; | |
71 | ||
72 | struct bvec_iter iter; | |
73 | ||
74 | struct work_struct work; | |
75 | ||
76 | /* | |
77 | * Three variably-size fields follow this struct: | |
78 | * | |
79 | * u8 hash_desc[v->shash_descsize]; | |
80 | * u8 real_digest[v->digest_size]; | |
81 | * u8 want_digest[v->digest_size]; | |
82 | * | |
83 | * To access them use: verity_io_hash_desc(), verity_io_real_digest() | |
84 | * and verity_io_want_digest(). | |
85 | */ | |
86 | }; | |
87 | ||
88 | static inline struct shash_desc *verity_io_hash_desc(struct dm_verity *v, | |
89 | struct dm_verity_io *io) | |
90 | { | |
91 | return (struct shash_desc *)(io + 1); | |
92 | } | |
93 | ||
94 | static inline u8 *verity_io_real_digest(struct dm_verity *v, | |
95 | struct dm_verity_io *io) | |
96 | { | |
97 | return (u8 *)(io + 1) + v->shash_descsize; | |
98 | } | |
99 | ||
100 | static inline u8 *verity_io_want_digest(struct dm_verity *v, | |
101 | struct dm_verity_io *io) | |
102 | { | |
103 | return (u8 *)(io + 1) + v->shash_descsize + v->digest_size; | |
104 | } | |
105 | ||
106 | extern int verity_hash(struct dm_verity *v, struct shash_desc *desc, | |
107 | const u8 *data, size_t len, u8 *digest); | |
108 | ||
109 | extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, | |
110 | sector_t block, u8 *digest); | |
111 | ||
112 | #endif /* DM_VERITY_H */ |