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 DM_VERITY_MODE_PANIC 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_fec; 33 34 struct dm_verity { 35 struct dm_dev *data_dev; 36 struct dm_dev *hash_dev; 37 struct dm_target *ti; 38 struct dm_bufio_client *bufio; 39 char *alg_name; 40 struct crypto_ahash *tfm; 41 u8 *root_digest; /* digest of the root block */ 42 u8 *salt; /* salt: its size is salt_size */ 43 u8 *zero_digest; /* digest for a zero block */ 44 unsigned salt_size; 45 sector_t data_start; /* data offset in 512-byte sectors */ 46 sector_t hash_start; /* hash start in blocks */ 47 sector_t data_blocks; /* the number of data blocks */ 48 sector_t hash_blocks; /* the number of hash blocks */ 49 unsigned char data_dev_block_bits; /* log2(data blocksize) */ 50 unsigned char hash_dev_block_bits; /* log2(hash blocksize) */ 51 unsigned char hash_per_block_bits; /* log2(hashes in hash block) */ 52 unsigned char levels; /* the number of tree levels */ 53 unsigned char version; 54 unsigned digest_size; /* digest size for the current hash algorithm */ 55 unsigned int ahash_reqsize;/* the size of temporary space for crypto */ 56 int hash_failed; /* set to 1 if hash of any block failed */ 57 enum verity_mode mode; /* mode for handling verification errors */ 58 unsigned corrupted_errs;/* Number of errors for corrupted blocks */ 59 60 struct workqueue_struct *verify_wq; 61 62 /* starting blocks for each tree level. 0 is the lowest level. */ 63 sector_t hash_level_block[DM_VERITY_MAX_LEVELS]; 64 65 struct dm_verity_fec *fec; /* forward error correction */ 66 unsigned long *validated_blocks; /* bitset blocks validated */ 67 68 char *signature_key_desc; /* signature keyring reference */ 69 }; 70 71 struct dm_verity_io { 72 struct dm_verity *v; 73 74 /* original value of bio->bi_end_io */ 75 bio_end_io_t *orig_bi_end_io; 76 77 sector_t block; 78 unsigned n_blocks; 79 80 struct bvec_iter iter; 81 82 struct work_struct work; 83 84 /* 85 * Three variably-size fields follow this struct: 86 * 87 * u8 hash_req[v->ahash_reqsize]; 88 * u8 real_digest[v->digest_size]; 89 * u8 want_digest[v->digest_size]; 90 * 91 * To access them use: verity_io_hash_req(), verity_io_real_digest() 92 * and verity_io_want_digest(). 93 */ 94 }; 95 96 static inline struct ahash_request *verity_io_hash_req(struct dm_verity *v, 97 struct dm_verity_io *io) 98 { 99 return (struct ahash_request *)(io + 1); 100 } 101 102 static inline u8 *verity_io_real_digest(struct dm_verity *v, 103 struct dm_verity_io *io) 104 { 105 return (u8 *)(io + 1) + v->ahash_reqsize; 106 } 107 108 static inline u8 *verity_io_want_digest(struct dm_verity *v, 109 struct dm_verity_io *io) 110 { 111 return (u8 *)(io + 1) + v->ahash_reqsize + v->digest_size; 112 } 113 114 static inline u8 *verity_io_digest_end(struct dm_verity *v, 115 struct dm_verity_io *io) 116 { 117 return verity_io_want_digest(v, io) + v->digest_size; 118 } 119 120 extern int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io, 121 struct bvec_iter *iter, 122 int (*process)(struct dm_verity *v, 123 struct dm_verity_io *io, 124 u8 *data, size_t len)); 125 126 extern int verity_hash(struct dm_verity *v, struct ahash_request *req, 127 const u8 *data, size_t len, u8 *digest); 128 129 extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, 130 sector_t block, u8 *digest, bool *is_zero); 131 132 #endif /* DM_VERITY_H */ 133