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_shash *shash_tfm; 43 u8 *root_digest; /* digest of the root block */ 44 u8 *salt; /* salt: its size is salt_size */ 45 u8 *initial_hashstate; /* salted initial state, if version >= 1 */ 46 u8 *zero_digest; /* digest for a zero block */ 47 #ifdef CONFIG_SECURITY 48 u8 *root_digest_sig; /* signature of the root digest */ 49 unsigned int sig_size; /* root digest signature size */ 50 #endif /* CONFIG_SECURITY */ 51 unsigned int salt_size; 52 sector_t hash_start; /* hash start in blocks */ 53 sector_t data_blocks; /* the number of data blocks */ 54 sector_t hash_blocks; /* the number of hash blocks */ 55 unsigned char data_dev_block_bits; /* log2(data blocksize) */ 56 unsigned char hash_dev_block_bits; /* log2(hash blocksize) */ 57 unsigned char hash_per_block_bits; /* log2(hashes in hash block) */ 58 unsigned char levels; /* the number of tree levels */ 59 unsigned char version; 60 bool hash_failed:1; /* set if hash of any block failed */ 61 bool use_bh_wq:1; /* try to verify in BH wq before normal work-queue */ 62 unsigned int digest_size; /* digest size for the current hash algorithm */ 63 enum verity_mode mode; /* mode for handling verification errors */ 64 enum verity_mode error_mode;/* mode for handling I/O errors */ 65 unsigned int corrupted_errs;/* Number of errors for corrupted blocks */ 66 67 struct workqueue_struct *verify_wq; 68 69 /* starting blocks for each tree level. 0 is the lowest level. */ 70 sector_t hash_level_block[DM_VERITY_MAX_LEVELS]; 71 72 struct dm_verity_fec *fec; /* forward error correction */ 73 unsigned long *validated_blocks; /* bitset blocks validated */ 74 75 char *signature_key_desc; /* signature keyring reference */ 76 77 struct dm_io_client *io; 78 mempool_t recheck_pool; 79 }; 80 81 struct dm_verity_io { 82 struct dm_verity *v; 83 84 /* original value of bio->bi_end_io */ 85 bio_end_io_t *orig_bi_end_io; 86 87 struct bvec_iter iter; 88 89 sector_t block; 90 unsigned int n_blocks; 91 bool in_bh; 92 bool had_mismatch; 93 94 struct work_struct work; 95 struct work_struct bh_work; 96 97 u8 real_digest[HASH_MAX_DIGESTSIZE]; 98 u8 want_digest[HASH_MAX_DIGESTSIZE]; 99 100 /* 101 * Temporary space for hashing. This is variable-length and must be at 102 * the end of the struct. struct shash_desc is just the fixed part; 103 * it's followed by a context of size crypto_shash_descsize(shash_tfm). 104 */ 105 struct shash_desc hash_desc; 106 }; 107 108 static inline u8 *verity_io_real_digest(struct dm_verity *v, 109 struct dm_verity_io *io) 110 { 111 return io->real_digest; 112 } 113 114 static inline u8 *verity_io_want_digest(struct dm_verity *v, 115 struct dm_verity_io *io) 116 { 117 return io->want_digest; 118 } 119 120 extern int verity_hash(struct dm_verity *v, struct dm_verity_io *io, 121 const u8 *data, size_t len, u8 *digest); 122 123 extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, 124 sector_t block, u8 *digest, bool *is_zero); 125 126 extern bool dm_is_verity_target(struct dm_target *ti); 127 extern int dm_verity_get_mode(struct dm_target *ti); 128 extern int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest, 129 unsigned int *digest_size); 130 131 #endif /* DM_VERITY_H */ 132