/* * Copyright (C) 2012 Red Hat, Inc. * Copyright (C) 2015 Google, Inc. * * Author: Mikulas Patocka <mpatocka@redhat.com> * * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors * * This file is released under the GPLv2. */ #ifndef DM_VERITY_H #define DM_VERITY_H #include "dm-bufio.h" #include <linux/device-mapper.h> #include <crypto/hash.h> #define DM_VERITY_MAX_LEVELS 63 enum verity_mode { DM_VERITY_MODE_EIO, DM_VERITY_MODE_LOGGING, DM_VERITY_MODE_RESTART }; enum verity_block_type { DM_VERITY_BLOCK_TYPE_DATA, DM_VERITY_BLOCK_TYPE_METADATA }; struct dm_verity_fec; struct dm_verity { struct dm_dev *data_dev; struct dm_dev *hash_dev; struct dm_target *ti; struct dm_bufio_client *bufio; char *alg_name; struct crypto_shash *tfm; u8 *root_digest; /* digest of the root block */ u8 *salt; /* salt: its size is salt_size */ u8 *zero_digest; /* digest for a zero block */ unsigned salt_size; sector_t data_start; /* data offset in 512-byte sectors */ sector_t hash_start; /* hash start in blocks */ sector_t data_blocks; /* the number of data blocks */ sector_t hash_blocks; /* the number of hash blocks */ unsigned char data_dev_block_bits; /* log2(data blocksize) */ unsigned char hash_dev_block_bits; /* log2(hash blocksize) */ unsigned char hash_per_block_bits; /* log2(hashes in hash block) */ unsigned char levels; /* the number of tree levels */ unsigned char version; unsigned digest_size; /* digest size for the current hash algorithm */ unsigned shash_descsize;/* the size of temporary space for crypto */ int hash_failed; /* set to 1 if hash of any block failed */ enum verity_mode mode; /* mode for handling verification errors */ unsigned corrupted_errs;/* Number of errors for corrupted blocks */ struct workqueue_struct *verify_wq; /* starting blocks for each tree level. 0 is the lowest level. */ sector_t hash_level_block[DM_VERITY_MAX_LEVELS]; struct dm_verity_fec *fec; /* forward error correction */ }; struct dm_verity_io { struct dm_verity *v; /* original value of bio->bi_end_io */ bio_end_io_t *orig_bi_end_io; sector_t block; unsigned n_blocks; struct bvec_iter iter; struct work_struct work; /* * Three variably-size fields follow this struct: * * u8 hash_desc[v->shash_descsize]; * u8 real_digest[v->digest_size]; * u8 want_digest[v->digest_size]; * * To access them use: verity_io_hash_desc(), verity_io_real_digest() * and verity_io_want_digest(). */ }; static inline struct shash_desc *verity_io_hash_desc(struct dm_verity *v, struct dm_verity_io *io) { return (struct shash_desc *)(io + 1); } static inline u8 *verity_io_real_digest(struct dm_verity *v, struct dm_verity_io *io) { return (u8 *)(io + 1) + v->shash_descsize; } static inline u8 *verity_io_want_digest(struct dm_verity *v, struct dm_verity_io *io) { return (u8 *)(io + 1) + v->shash_descsize + v->digest_size; } static inline u8 *verity_io_digest_end(struct dm_verity *v, struct dm_verity_io *io) { return verity_io_want_digest(v, io) + v->digest_size; } extern int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io, struct bvec_iter *iter, int (*process)(struct dm_verity *v, struct dm_verity_io *io, u8 *data, size_t len)); extern int verity_hash(struct dm_verity *v, struct shash_desc *desc, const u8 *data, size_t len, u8 *digest); extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, sector_t block, u8 *digest, bool *is_zero); #endif /* DM_VERITY_H */