1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2 | /* |
3 | * Copyright (C) 2012 Red Hat, Inc. |
4 | * Copyright (C) 2015 Google, Inc. |
5 | * |
6 | * Author: Mikulas Patocka <mpatocka@redhat.com> |
7 | * |
8 | * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors |
9 | */ |
10 | |
11 | #ifndef DM_VERITY_H |
12 | #define DM_VERITY_H |
13 | |
14 | #include <linux/dm-bufio.h> |
15 | #include <linux/device-mapper.h> |
16 | #include <linux/interrupt.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 | DM_VERITY_MODE_PANIC |
26 | }; |
27 | |
28 | enum verity_block_type { |
29 | DM_VERITY_BLOCK_TYPE_DATA, |
30 | DM_VERITY_BLOCK_TYPE_METADATA |
31 | }; |
32 | |
33 | struct dm_verity_fec; |
34 | |
35 | struct dm_verity { |
36 | struct dm_dev *data_dev; |
37 | struct dm_dev *hash_dev; |
38 | struct dm_target *ti; |
39 | struct dm_bufio_client *bufio; |
40 | char *alg_name; |
41 | struct crypto_ahash *tfm; |
42 | u8 *root_digest; /* digest of the root block */ |
43 | u8 *salt; /* salt: its size is salt_size */ |
44 | u8 *zero_digest; /* digest for a zero block */ |
45 | unsigned int salt_size; |
46 | sector_t data_start; /* data offset in 512-byte sectors */ |
47 | sector_t hash_start; /* hash start in blocks */ |
48 | sector_t data_blocks; /* the number of data blocks */ |
49 | sector_t hash_blocks; /* the number of hash blocks */ |
50 | unsigned char data_dev_block_bits; /* log2(data blocksize) */ |
51 | unsigned char hash_dev_block_bits; /* log2(hash blocksize) */ |
52 | unsigned char hash_per_block_bits; /* log2(hashes in hash block) */ |
53 | unsigned char levels; /* the number of tree levels */ |
54 | unsigned char version; |
55 | bool hash_failed:1; /* set if hash of any block failed */ |
56 | bool use_tasklet:1; /* try to verify in tasklet before work-queue */ |
57 | unsigned int digest_size; /* digest size for the current hash algorithm */ |
58 | unsigned int ahash_reqsize;/* the size of temporary space for crypto */ |
59 | enum verity_mode mode; /* mode for handling verification errors */ |
60 | unsigned int corrupted_errs;/* Number of errors for corrupted blocks */ |
61 | |
62 | struct workqueue_struct *verify_wq; |
63 | |
64 | /* starting blocks for each tree level. 0 is the lowest level. */ |
65 | sector_t hash_level_block[DM_VERITY_MAX_LEVELS]; |
66 | |
67 | struct dm_verity_fec *fec; /* forward error correction */ |
68 | unsigned long *validated_blocks; /* bitset blocks validated */ |
69 | |
70 | char *signature_key_desc; /* signature keyring reference */ |
71 | }; |
72 | |
73 | struct dm_verity_io { |
74 | struct dm_verity *v; |
75 | |
76 | /* original value of bio->bi_end_io */ |
77 | bio_end_io_t *orig_bi_end_io; |
78 | |
79 | sector_t block; |
80 | unsigned int n_blocks; |
81 | bool in_tasklet; |
82 | |
83 | struct bvec_iter iter; |
84 | |
85 | struct work_struct work; |
86 | struct tasklet_struct tasklet; |
87 | |
88 | /* |
89 | * Three variably-size fields follow this struct: |
90 | * |
91 | * u8 hash_req[v->ahash_reqsize]; |
92 | * u8 real_digest[v->digest_size]; |
93 | * u8 want_digest[v->digest_size]; |
94 | * |
95 | * To access them use: verity_io_hash_req(), verity_io_real_digest() |
96 | * and verity_io_want_digest(). |
97 | */ |
98 | }; |
99 | |
100 | static inline struct ahash_request *verity_io_hash_req(struct dm_verity *v, |
101 | struct dm_verity_io *io) |
102 | { |
103 | return (struct ahash_request *)(io + 1); |
104 | } |
105 | |
106 | static inline u8 *verity_io_real_digest(struct dm_verity *v, |
107 | struct dm_verity_io *io) |
108 | { |
109 | return (u8 *)(io + 1) + v->ahash_reqsize; |
110 | } |
111 | |
112 | static inline u8 *verity_io_want_digest(struct dm_verity *v, |
113 | struct dm_verity_io *io) |
114 | { |
115 | return (u8 *)(io + 1) + v->ahash_reqsize + v->digest_size; |
116 | } |
117 | |
118 | static inline u8 *verity_io_digest_end(struct dm_verity *v, |
119 | struct dm_verity_io *io) |
120 | { |
121 | return verity_io_want_digest(v, io) + v->digest_size; |
122 | } |
123 | |
124 | extern int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io, |
125 | struct bvec_iter *iter, |
126 | int (*process)(struct dm_verity *v, |
127 | struct dm_verity_io *io, |
128 | u8 *data, size_t len)); |
129 | |
130 | extern int verity_hash(struct dm_verity *v, struct ahash_request *req, |
131 | const u8 *data, size_t len, u8 *digest); |
132 | |
133 | extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, |
134 | sector_t block, u8 *digest, bool *is_zero); |
135 | |
136 | extern bool dm_is_verity_target(struct dm_target *ti); |
137 | extern int dm_verity_get_mode(struct dm_target *ti); |
138 | extern int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest, |
139 | unsigned int *digest_size); |
140 | |
141 | #endif /* DM_VERITY_H */ |
142 | |