Home Home > GIT Browse
summaryrefslogtreecommitdiff
blob: a59e0ada6fd32d01b80c4032a25a67c90b048417 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
/*
 * Copyright (C) 2012 Red Hat, Inc.
 * Copyright (C) 2015 Google, Inc.
 *
 * Author: Mikulas Patocka <mpatocka@redhat.com>
 *
 * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors
 *
 * This file is released under the GPLv2.
 */

#ifndef DM_VERITY_H
#define DM_VERITY_H

#include "dm-bufio.h"
#include <linux/device-mapper.h>
#include <crypto/hash.h>

#define DM_VERITY_MAX_LEVELS		63

enum verity_mode {
	DM_VERITY_MODE_EIO,
	DM_VERITY_MODE_LOGGING,
	DM_VERITY_MODE_RESTART
};

enum verity_block_type {
	DM_VERITY_BLOCK_TYPE_DATA,
	DM_VERITY_BLOCK_TYPE_METADATA
};

struct dm_verity_fec;

struct dm_verity {
	struct dm_dev *data_dev;
	struct dm_dev *hash_dev;
	struct dm_target *ti;
	struct dm_bufio_client *bufio;
	char *alg_name;
	struct crypto_ahash *tfm;
	u8 *root_digest;	/* digest of the root block */
	u8 *salt;		/* salt: its size is salt_size */
	u8 *zero_digest;	/* digest for a zero block */
	unsigned salt_size;
	sector_t data_start;	/* data offset in 512-byte sectors */
	sector_t hash_start;	/* hash start in blocks */
	sector_t data_blocks;	/* the number of data blocks */
	sector_t hash_blocks;	/* the number of hash blocks */
	unsigned char data_dev_block_bits;	/* log2(data blocksize) */
	unsigned char hash_dev_block_bits;	/* log2(hash blocksize) */
	unsigned char hash_per_block_bits;	/* log2(hashes in hash block) */
	unsigned char levels;	/* the number of tree levels */
	unsigned char version;
	unsigned digest_size;	/* digest size for the current hash algorithm */
	unsigned int ahash_reqsize;/* the size of temporary space for crypto */
	int hash_failed;	/* set to 1 if hash of any block failed */
	enum verity_mode mode;	/* mode for handling verification errors */
	unsigned corrupted_errs;/* Number of errors for corrupted blocks */

	struct workqueue_struct *verify_wq;

	/* starting blocks for each tree level. 0 is the lowest level. */
	sector_t hash_level_block[DM_VERITY_MAX_LEVELS];

	struct dm_verity_fec *fec;	/* forward error correction */
};

struct dm_verity_io {
	struct dm_verity *v;

	/* original value of bio->bi_end_io */
	bio_end_io_t *orig_bi_end_io;

	sector_t block;
	unsigned n_blocks;

	struct bvec_iter iter;

	struct work_struct work;

	/*
	 * Three variably-size fields follow this struct:
	 *
	 * u8 hash_req[v->ahash_reqsize];
	 * u8 real_digest[v->digest_size];
	 * u8 want_digest[v->digest_size];
	 *
	 * To access them use: verity_io_hash_req(), verity_io_real_digest()
	 * and verity_io_want_digest().
	 */
};

struct verity_result {
	struct completion completion;
	int err;
};

static inline struct ahash_request *verity_io_hash_req(struct dm_verity *v,
						     struct dm_verity_io *io)
{
	return (struct ahash_request *)(io + 1);
}

static inline u8 *verity_io_real_digest(struct dm_verity *v,
					struct dm_verity_io *io)
{
	return (u8 *)(io + 1) + v->ahash_reqsize;
}

static inline u8 *verity_io_want_digest(struct dm_verity *v,
					struct dm_verity_io *io)
{
	return (u8 *)(io + 1) + v->ahash_reqsize + v->digest_size;
}

static inline u8 *verity_io_digest_end(struct dm_verity *v,
				       struct dm_verity_io *io)
{
	return verity_io_want_digest(v, io) + v->digest_size;
}

extern int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
			       struct bvec_iter *iter,
			       int (*process)(struct dm_verity *v,
					      struct dm_verity_io *io,
					      u8 *data, size_t len));

extern int verity_hash(struct dm_verity *v, struct ahash_request *req,
		       const u8 *data, size_t len, u8 *digest);

extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
				 sector_t block, u8 *digest, bool *is_zero);

#endif /* DM_VERITY_H */