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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* 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
*/
#ifndef DM_VERITY_H
#define DM_VERITY_H
#include <linux/dm-io.h>
#include <linux/dm-bufio.h>
#include <linux/device-mapper.h>
#include <linux/interrupt.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,
DM_VERITY_MODE_PANIC
};
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_ahash *ahash_tfm; /* either this or shash_tfm is set */
struct crypto_shash *shash_tfm; /* either this or ahash_tfm is set */
u8 *root_digest; /* digest of the root block */
u8 *salt; /* salt: its size is salt_size */
u8 *initial_hashstate; /* salted initial state, if shash_tfm is set */
u8 *zero_digest; /* digest for a zero block */
#ifdef CONFIG_SECURITY
u8 *root_digest_sig; /* signature of the root digest */
unsigned int sig_size; /* root digest signature size */
#endif /* CONFIG_SECURITY */
unsigned int 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;
bool hash_failed:1; /* set if hash of any block failed */
bool use_bh_wq:1; /* try to verify in BH wq before normal work-queue */
unsigned int digest_size; /* digest size for the current hash algorithm */
unsigned int hash_reqsize; /* the size of temporary space for crypto */
enum verity_mode mode; /* mode for handling verification errors */
enum verity_mode error_mode;/* mode for handling I/O errors */
unsigned int 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 */
unsigned long *validated_blocks; /* bitset blocks validated */
char *signature_key_desc; /* signature keyring reference */
struct dm_io_client *io;
mempool_t recheck_pool;
};
struct dm_verity_io {
struct dm_verity *v;
/* original value of bio->bi_end_io */
bio_end_io_t *orig_bi_end_io;
struct bvec_iter iter;
sector_t block;
unsigned int n_blocks;
bool in_bh;
struct work_struct work;
struct work_struct bh_work;
u8 real_digest[HASH_MAX_DIGESTSIZE];
u8 want_digest[HASH_MAX_DIGESTSIZE];
/*
* This struct is followed by a variable-sized hash request of size
* v->hash_reqsize, either a struct ahash_request or a struct shash_desc
* (depending on whether ahash_tfm or shash_tfm is being used). To
* access it, use verity_io_hash_req().
*/
};
static inline void *verity_io_hash_req(struct dm_verity *v,
struct dm_verity_io *io)
{
return io + 1;
}
static inline u8 *verity_io_real_digest(struct dm_verity *v,
struct dm_verity_io *io)
{
return io->real_digest;
}
static inline u8 *verity_io_want_digest(struct dm_verity *v,
struct dm_verity_io *io)
{
return io->want_digest;
}
extern int verity_hash(struct dm_verity *v, struct dm_verity_io *io,
const u8 *data, size_t len, u8 *digest, bool may_sleep);
extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
sector_t block, u8 *digest, bool *is_zero);
extern bool dm_is_verity_target(struct dm_target *ti);
extern int dm_verity_get_mode(struct dm_target *ti);
extern int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest,
unsigned int *digest_size);
#endif /* DM_VERITY_H */
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