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 #include <crypto/sha2.h> 20 21 #define DM_VERITY_MAX_LEVELS 63 22 23 enum verity_mode { 24 DM_VERITY_MODE_EIO, 25 DM_VERITY_MODE_LOGGING, 26 DM_VERITY_MODE_RESTART, 27 DM_VERITY_MODE_PANIC 28 }; 29 30 enum verity_block_type { 31 DM_VERITY_BLOCK_TYPE_DATA, 32 DM_VERITY_BLOCK_TYPE_METADATA 33 }; 34 35 struct dm_verity_fec; 36 37 struct dm_verity { 38 struct dm_dev *data_dev; 39 struct dm_dev *hash_dev; 40 struct dm_target *ti; 41 struct dm_bufio_client *bufio; 42 char *alg_name; 43 struct crypto_shash *shash_tfm; 44 u8 *root_digest; /* digest of the root block */ 45 u8 *salt; /* salt: its size is salt_size */ 46 union { 47 struct sha256_ctx *sha256; /* for use_sha256_lib=1 */ 48 u8 *shash; /* for use_sha256_lib=0 */ 49 } initial_hashstate; /* salted initial state, if version >= 1 */ 50 u8 *zero_digest; /* digest for a zero block */ 51 #ifdef CONFIG_SECURITY 52 u8 *root_digest_sig; /* signature of the root digest */ 53 unsigned int sig_size; /* root digest signature size */ 54 #endif /* CONFIG_SECURITY */ 55 unsigned int salt_size; 56 sector_t hash_start; /* hash start in blocks */ 57 sector_t data_blocks; /* the number of data blocks */ 58 sector_t hash_blocks; /* the number of hash blocks */ 59 unsigned char data_dev_block_bits; /* log2(data blocksize) */ 60 unsigned char hash_dev_block_bits; /* log2(hash blocksize) */ 61 unsigned char hash_per_block_bits; /* log2(hashes in hash block) */ 62 unsigned char levels; /* the number of tree levels */ 63 unsigned char version; 64 bool hash_failed:1; /* set if hash of any block failed */ 65 bool use_bh_wq:1; /* try to verify in BH wq before normal work-queue */ 66 bool use_sha256_lib:1; /* use SHA-256 library instead of generic crypto API */ 67 bool use_sha256_finup_2x:1; /* use interleaved hashing optimization */ 68 unsigned int digest_size; /* digest size for the current hash algorithm */ 69 enum verity_mode mode; /* mode for handling verification errors */ 70 enum verity_mode error_mode;/* mode for handling I/O errors */ 71 unsigned int corrupted_errs;/* Number of errors for corrupted blocks */ 72 73 struct workqueue_struct *verify_wq; 74 75 /* starting blocks for each tree level. 0 is the lowest level. */ 76 sector_t hash_level_block[DM_VERITY_MAX_LEVELS]; 77 78 struct dm_verity_fec *fec; /* forward error correction */ 79 unsigned long *validated_blocks; /* bitset blocks validated */ 80 81 char *signature_key_desc; /* signature keyring reference */ 82 83 struct dm_io_client *io; 84 mempool_t recheck_pool; 85 }; 86 87 struct pending_block { 88 void *data; 89 sector_t blkno; 90 u8 want_digest[HASH_MAX_DIGESTSIZE]; 91 u8 real_digest[HASH_MAX_DIGESTSIZE]; 92 }; 93 94 struct dm_verity_io { 95 struct dm_verity *v; 96 97 /* original value of bio->bi_end_io */ 98 bio_end_io_t *orig_bi_end_io; 99 100 struct bvec_iter iter; 101 102 sector_t block; 103 unsigned int n_blocks; 104 bool in_bh; 105 bool had_mismatch; 106 107 struct work_struct work; 108 struct work_struct bh_work; 109 110 u8 tmp_digest[HASH_MAX_DIGESTSIZE]; 111 112 /* 113 * This is the queue of data blocks that are pending verification. When 114 * the crypto layer supports interleaved hashing, we allow multiple 115 * blocks to be queued up in order to utilize it. This can improve 116 * performance significantly vs. sequential hashing of each block. 117 */ 118 int num_pending; 119 struct pending_block pending_blocks[2]; 120 121 /* 122 * Temporary space for hashing. Either sha256 or shash is used, 123 * depending on the value of use_sha256_lib. If shash is used, 124 * then this field is variable-length, with total size 125 * sizeof(struct shash_desc) + crypto_shash_descsize(shash_tfm). 126 * For this reason, this field must be the end of the struct. 127 */ 128 union { 129 struct sha256_ctx sha256; 130 struct shash_desc shash; 131 } hash_ctx; 132 }; 133 134 extern int verity_hash(struct dm_verity *v, struct dm_verity_io *io, 135 const u8 *data, size_t len, u8 *digest); 136 137 extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, 138 sector_t block, u8 *digest, bool *is_zero); 139 140 extern bool dm_is_verity_target(struct dm_target *ti); 141 extern int dm_verity_get_mode(struct dm_target *ti); 142 extern int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest, 143 unsigned int *digest_size); 144 145 #endif /* DM_VERITY_H */ 146