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 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 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 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 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_root_digest(struct dm_target *ti, u8 **root_digest, 138 unsigned int *digest_size); 139 140 #endif /* DM_VERITY_H */ 141