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Linux kernel mirror (for testing)
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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-io.h>
15#include <linux/dm-bufio.h>
16#include <linux/device-mapper.h>
17#include <linux/interrupt.h>
18#include <crypto/hash.h>
19
20#define DM_VERITY_MAX_LEVELS 63
21
22enum verity_mode {
23 DM_VERITY_MODE_EIO,
24 DM_VERITY_MODE_LOGGING,
25 DM_VERITY_MODE_RESTART,
26 DM_VERITY_MODE_PANIC
27};
28
29enum verity_block_type {
30 DM_VERITY_BLOCK_TYPE_DATA,
31 DM_VERITY_BLOCK_TYPE_METADATA
32};
33
34struct dm_verity_fec;
35
36struct dm_verity {
37 struct dm_dev *data_dev;
38 struct dm_dev *hash_dev;
39 struct dm_target *ti;
40 struct dm_bufio_client *bufio;
41 char *alg_name;
42 struct crypto_ahash *ahash_tfm; /* either this or shash_tfm is set */
43 struct crypto_shash *shash_tfm; /* either this or ahash_tfm is set */
44 u8 *root_digest; /* digest of the root block */
45 u8 *salt; /* salt: its size is salt_size */
46 u8 *initial_hashstate; /* salted initial state, if shash_tfm is set */
47 u8 *zero_digest; /* digest for a zero block */
48 unsigned int salt_size;
49 sector_t data_start; /* data offset in 512-byte sectors */
50 sector_t hash_start; /* hash start in blocks */
51 sector_t data_blocks; /* the number of data blocks */
52 sector_t hash_blocks; /* the number of hash blocks */
53 unsigned char data_dev_block_bits; /* log2(data blocksize) */
54 unsigned char hash_dev_block_bits; /* log2(hash blocksize) */
55 unsigned char hash_per_block_bits; /* log2(hashes in hash block) */
56 unsigned char levels; /* the number of tree levels */
57 unsigned char version;
58 bool hash_failed:1; /* set if hash of any block failed */
59 bool use_bh_wq:1; /* try to verify in BH wq before normal work-queue */
60 unsigned int digest_size; /* digest size for the current hash algorithm */
61 unsigned int hash_reqsize; /* the size of temporary space for crypto */
62 enum verity_mode mode; /* mode for handling verification errors */
63 unsigned int corrupted_errs;/* Number of errors for corrupted blocks */
64
65 struct workqueue_struct *verify_wq;
66
67 /* starting blocks for each tree level. 0 is the lowest level. */
68 sector_t hash_level_block[DM_VERITY_MAX_LEVELS];
69
70 struct dm_verity_fec *fec; /* forward error correction */
71 unsigned long *validated_blocks; /* bitset blocks validated */
72
73 char *signature_key_desc; /* signature keyring reference */
74
75 struct dm_io_client *io;
76 mempool_t recheck_pool;
77};
78
79struct dm_verity_io {
80 struct dm_verity *v;
81
82 /* original value of bio->bi_end_io */
83 bio_end_io_t *orig_bi_end_io;
84
85 struct bvec_iter iter;
86
87 sector_t block;
88 unsigned int n_blocks;
89 bool in_bh;
90
91 struct work_struct work;
92 struct work_struct bh_work;
93
94 u8 real_digest[HASH_MAX_DIGESTSIZE];
95 u8 want_digest[HASH_MAX_DIGESTSIZE];
96
97 /*
98 * This struct is followed by a variable-sized hash request of size
99 * v->hash_reqsize, either a struct ahash_request or a struct shash_desc
100 * (depending on whether ahash_tfm or shash_tfm is being used). To
101 * access it, use verity_io_hash_req().
102 */
103};
104
105static inline void *verity_io_hash_req(struct dm_verity *v,
106 struct dm_verity_io *io)
107{
108 return io + 1;
109}
110
111static inline u8 *verity_io_real_digest(struct dm_verity *v,
112 struct dm_verity_io *io)
113{
114 return io->real_digest;
115}
116
117static inline u8 *verity_io_want_digest(struct dm_verity *v,
118 struct dm_verity_io *io)
119{
120 return io->want_digest;
121}
122
123extern int verity_hash(struct dm_verity *v, struct dm_verity_io *io,
124 const u8 *data, size_t len, u8 *digest, bool may_sleep);
125
126extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
127 sector_t block, u8 *digest, bool *is_zero);
128
129extern bool dm_is_verity_target(struct dm_target *ti);
130extern int dm_verity_get_mode(struct dm_target *ti);
131extern int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest,
132 unsigned int *digest_size);
133
134#endif /* DM_VERITY_H */