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 <crypto/hash.h> 17 18 #define DM_VERITY_MAX_LEVELS 63 19 20 enum verity_mode { 21 DM_VERITY_MODE_EIO, 22 DM_VERITY_MODE_LOGGING, 23 DM_VERITY_MODE_RESTART 24 }; 25 26 enum verity_block_type { 27 DM_VERITY_BLOCK_TYPE_DATA, 28 DM_VERITY_BLOCK_TYPE_METADATA 29 }; 30 31 struct dm_verity_fec; 32 33 struct dm_verity { 34 struct dm_dev *data_dev; 35 struct dm_dev *hash_dev; 36 struct dm_target *ti; 37 struct dm_bufio_client *bufio; 38 char *alg_name; 39 struct crypto_ahash *tfm; 40 u8 *root_digest; /* digest of the root block */ 41 u8 *salt; /* salt: its size is salt_size */ 42 u8 *zero_digest; /* digest for a zero block */ 43 unsigned salt_size; 44 sector_t data_start; /* data offset in 512-byte sectors */ 45 sector_t hash_start; /* hash start in blocks */ 46 sector_t data_blocks; /* the number of data blocks */ 47 sector_t hash_blocks; /* the number of hash blocks */ 48 unsigned char data_dev_block_bits; /* log2(data blocksize) */ 49 unsigned char hash_dev_block_bits; /* log2(hash blocksize) */ 50 unsigned char hash_per_block_bits; /* log2(hashes in hash block) */ 51 unsigned char levels; /* the number of tree levels */ 52 unsigned char version; 53 unsigned digest_size; /* digest size for the current hash algorithm */ 54 unsigned int ahash_reqsize;/* the size of temporary space for crypto */ 55 int hash_failed; /* set to 1 if hash of any block failed */ 56 enum verity_mode mode; /* mode for handling verification errors */ 57 unsigned corrupted_errs;/* Number of errors for corrupted blocks */ 58 59 struct workqueue_struct *verify_wq; 60 61 /* starting blocks for each tree level. 0 is the lowest level. */ 62 sector_t hash_level_block[DM_VERITY_MAX_LEVELS]; 63 64 struct dm_verity_fec *fec; /* forward error correction */ 65 unsigned long *validated_blocks; /* bitset blocks validated */ 66 67 char *signature_key_desc; /* signature keyring reference */ 68 }; 69 70 struct dm_verity_io { 71 struct dm_verity *v; 72 73 /* original value of bio->bi_end_io */ 74 bio_end_io_t *orig_bi_end_io; 75 76 sector_t block; 77 unsigned n_blocks; 78 79 struct bvec_iter iter; 80 81 struct work_struct work; 82 83 /* 84 * Three variably-size fields follow this struct: 85 * 86 * u8 hash_req[v->ahash_reqsize]; 87 * u8 real_digest[v->digest_size]; 88 * u8 want_digest[v->digest_size]; 89 * 90 * To access them use: verity_io_hash_req(), verity_io_real_digest() 91 * and verity_io_want_digest(). 92 */ 93 }; 94 95 static inline struct ahash_request *verity_io_hash_req(struct dm_verity *v, 96 struct dm_verity_io *io) 97 { 98 return (struct ahash_request *)(io + 1); 99 } 100 101 static inline u8 *verity_io_real_digest(struct dm_verity *v, 102 struct dm_verity_io *io) 103 { 104 return (u8 *)(io + 1) + v->ahash_reqsize; 105 } 106 107 static inline u8 *verity_io_want_digest(struct dm_verity *v, 108 struct dm_verity_io *io) 109 { 110 return (u8 *)(io + 1) + v->ahash_reqsize + v->digest_size; 111 } 112 113 static inline u8 *verity_io_digest_end(struct dm_verity *v, 114 struct dm_verity_io *io) 115 { 116 return verity_io_want_digest(v, io) + v->digest_size; 117 } 118 119 extern int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io, 120 struct bvec_iter *iter, 121 int (*process)(struct dm_verity *v, 122 struct dm_verity_io *io, 123 u8 *data, size_t len)); 124 125 extern int verity_hash(struct dm_verity *v, struct ahash_request *req, 126 const u8 *data, size_t len, u8 *digest); 127 128 extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, 129 sector_t block, u8 *digest, bool *is_zero); 130 131 #endif /* DM_VERITY_H */ 132