[linux-block.git] / drivers / md / dm-verity.h

/* 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 *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 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 ahash_reqsize;/* the size of temporary space for crypto */
	enum verity_mode mode;	/* mode for handling verification 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;

	char *recheck_buffer;

	/*
	 * Three variably-size fields follow this struct:
	 *
	 * u8 hash_req[v->ahash_reqsize];
	 * u8 real_digest[v->digest_size];
	 * u8 want_digest[v->digest_size];
	 *
	 * To access them use: verity_io_hash_req(), verity_io_real_digest()
	 * and verity_io_want_digest().
	 */
};

static inline struct ahash_request *verity_io_hash_req(struct dm_verity *v,
						     struct dm_verity_io *io)
{
	return (struct ahash_request *)(io + 1);
}

static inline u8 *verity_io_real_digest(struct dm_verity *v,
					struct dm_verity_io *io)
{
	return (u8 *)(io + 1) + v->ahash_reqsize;
}

static inline u8 *verity_io_want_digest(struct dm_verity *v,
					struct dm_verity_io *io)
{
	return (u8 *)(io + 1) + v->ahash_reqsize + 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 ahash_request *req,
		       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 */
Commit	Line	Data
55716d26	1	/* SPDX-License-Identifier: GPL-2.0-only */
ffa39380 ST	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
ffa39380 ST	9	*/
	10
	11	#ifndef DM_VERITY_H
	12	#define DM_VERITY_H
	13
9177f3c0	14	#include <linux/dm-io.h>
afa53df8	15	#include <linux/dm-bufio.h>
ffa39380	16	#include <linux/device-mapper.h>
5721d4e5	17	#include <linux/interrupt.h>
ffa39380 ST	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,
e1fef0b0 JL	25	DM_VERITY_MODE_RESTART,
e1fef0b0 JL	26	DM_VERITY_MODE_PANIC
ffa39380 ST	27	};
	28
	29	enum verity_block_type {
	30	DM_VERITY_BLOCK_TYPE_DATA,
	31	DM_VERITY_BLOCK_TYPE_METADATA
	32	};
	33
a739ff3f ST	34	struct dm_verity_fec;
a739ff3f ST	35
ffa39380 ST	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;
d1ac3ff0	42	struct crypto_ahash *tfm;
ffa39380 ST	43	u8 root_digest; / digest of the root block */
ffa39380 ST	44	u8 salt; / salt: its size is salt_size */
0cc37c2d	45	u8 zero_digest; / digest for a zero block */
86a3238c	46	unsigned int salt_size;
ffa39380 ST	47	sector_t data_start; /* data offset in 512-byte sectors */
	48	sector_t hash_start; /* hash start in blocks */
	49	sector_t data_blocks; /* the number of data blocks */
	50	sector_t hash_blocks; /* the number of hash blocks */
	51	unsigned char data_dev_block_bits; /* log2(data blocksize) */
	52	unsigned char hash_dev_block_bits; /* log2(hash blocksize) */
	53	unsigned char hash_per_block_bits; /* log2(hashes in hash block) */
	54	unsigned char levels; /* the number of tree levels */
	55	unsigned char version;
5721d4e5	56	bool hash_failed:1; /* set if hash of any block failed */
c375b223	57	bool use_bh_wq:1; /* try to verify in BH wq before normal work-queue */
86a3238c	58	unsigned int digest_size; /* digest size for the current hash algorithm */
d1ac3ff0	59	unsigned int ahash_reqsize;/* the size of temporary space for crypto */
ffa39380	60	enum verity_mode mode; /* mode for handling verification errors */
86a3238c	61	unsigned int corrupted_errs;/* Number of errors for corrupted blocks */
ffa39380 ST	62
	63	struct workqueue_struct *verify_wq;
	64
	65	/* starting blocks for each tree level. 0 is the lowest level. */
	66	sector_t hash_level_block[DM_VERITY_MAX_LEVELS];
a739ff3f ST	67
a739ff3f ST	68	struct dm_verity_fec fec; / forward error correction */
843f38d3	69	unsigned long validated_blocks; / bitset blocks validated */
88cd3e6c JK	70
88cd3e6c JK	71	char signature_key_desc; / signature keyring reference */
9177f3c0 MP	72
	73	struct dm_io_client *io;
	74	mempool_t recheck_pool;
ffa39380 ST	75	};
	76
	77	struct dm_verity_io {
	78	struct dm_verity *v;
	79
	80	/* original value of bio->bi_end_io */
	81	bio_end_io_t *orig_bi_end_io;
	82
787f1b28 MP	83	struct bvec_iter iter;
787f1b28 MP	84
ffa39380	85	sector_t block;
86a3238c	86	unsigned int n_blocks;
c375b223	87	bool in_bh;
ffa39380	88
ffa39380	89	struct work_struct work;
c375b223	90	struct work_struct bh_work;
ffa39380	91
9177f3c0 MP	92	char *recheck_buffer;
9177f3c0 MP	93
ffa39380 ST	94	/*
	95	* Three variably-size fields follow this struct:
	96	*
d1ac3ff0	97	* u8 hash_req[v->ahash_reqsize];
ffa39380 ST	98	* u8 real_digest[v->digest_size];
	99	* u8 want_digest[v->digest_size];
	100	*
d1ac3ff0	101	* To access them use: verity_io_hash_req(), verity_io_real_digest()
ffa39380 ST	102	* and verity_io_want_digest().
	103	*/
	104	};
	105
d1ac3ff0	106	static inline struct ahash_request verity_io_hash_req(struct dm_verity v,
ffa39380 ST	107	struct dm_verity_io *io)
ffa39380 ST	108	{
d1ac3ff0	109	return (struct ahash_request *)(io + 1);
ffa39380 ST	110	}
	111
	112	static inline u8 verity_io_real_digest(struct dm_verity v,
	113	struct dm_verity_io *io)
	114	{
d1ac3ff0	115	return (u8 *)(io + 1) + v->ahash_reqsize;
ffa39380 ST	116	}
	117
	118	static inline u8 verity_io_want_digest(struct dm_verity v,
	119	struct dm_verity_io *io)
	120	{
d1ac3ff0	121	return (u8 *)(io + 1) + v->ahash_reqsize + v->digest_size;
ffa39380 ST	122	}
ffa39380 ST	123
bb4d73ac ST	124	extern int verity_for_bv_block(struct dm_verity v, struct dm_verity_io io,
	125	struct bvec_iter *iter,
	126	int (process)(struct dm_verity v,
	127	struct dm_verity_io *io,
	128	u8 *data, size_t len));
	129
d1ac3ff0	130	extern int verity_hash(struct dm_verity v, struct ahash_request req,
28f07f2a	131	const u8 data, size_t len, u8 digest, bool may_sleep);
ffa39380 ST	132
ffa39380 ST	133	extern int verity_hash_for_block(struct dm_verity v, struct dm_verity_io io,
0cc37c2d	134	sector_t block, u8 digest, bool is_zero);
ffa39380	135
b6c1c574	136	extern bool dm_is_verity_target(struct dm_target *ti);
916ef623	137	extern int dm_verity_get_mode(struct dm_target *ti);
b6c1c574 MK	138	extern int dm_verity_get_root_digest(struct dm_target ti, u8 *root_digest,
	139	unsigned int *digest_size);
	140
ffa39380	141	#endif /* DM_VERITY_H */