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 22 enum verity_mode { 23 DM_VERITY_MODE_EIO, 24 DM_VERITY_MODE_LOGGING, 25 DM_VERITY_MODE_RESTART, 26 DM_VERITY_MODE_PANIC 27 }; 28 29 enum verity_block_type { 30 DM_VERITY_BLOCK_TYPE_DATA, 31 DM_VERITY_BLOCK_TYPE_METADATA 32 }; 33 34 struct dm_verity_fec; 35 36 struct 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 79 struct 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 }; 104 105 static inline void *verity_io_hash_req(struct dm_verity *v, 106 struct dm_verity_io *io) 107 { 108 return io + 1; 109 } 110 111 static inline u8 *verity_io_real_digest(struct dm_verity *v, 112 struct dm_verity_io *io) 113 { 114 return io->real_digest; 115 } 116 117 static inline u8 *verity_io_want_digest(struct dm_verity *v, 118 struct dm_verity_io *io) 119 { 120 return io->want_digest; 121 } 122 123 extern int verity_hash(struct dm_verity *v, struct dm_verity_io *io, 124 const u8 *data, size_t len, u8 *digest, bool may_sleep); 125 126 extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, 127 sector_t block, u8 *digest, bool *is_zero); 128 129 extern bool dm_is_verity_target(struct dm_target *ti); 130 extern int dm_verity_get_mode(struct dm_target *ti); 131 extern int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest, 132 unsigned int *digest_size); 133 134 #endif /* DM_VERITY_H */ 135