[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-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 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_tasklet:1;	/* try to verify in tasklet before work-queue */
	unsigned 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 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_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;
	bool in_tasklet;

	struct bvec_iter iter;

	struct work_struct work;
	struct tasklet_struct tasklet;

	/*
	 * 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;
}

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 ahash_request *req,
		       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);

extern bool dm_is_verity_target(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
afa53df8	14	#include <linux/dm-bufio.h>
ffa39380	15	#include <linux/device-mapper.h>
5721d4e5	16	#include <linux/interrupt.h>
ffa39380 ST	17	#include <crypto/hash.h>
	18
	19	#define DM_VERITY_MAX_LEVELS 63
	20
	21	enum verity_mode {
	22	DM_VERITY_MODE_EIO,
	23	DM_VERITY_MODE_LOGGING,
e1fef0b0 JL	24	DM_VERITY_MODE_RESTART,
e1fef0b0 JL	25	DM_VERITY_MODE_PANIC
ffa39380 ST	26	};
	27
	28	enum verity_block_type {
	29	DM_VERITY_BLOCK_TYPE_DATA,
	30	DM_VERITY_BLOCK_TYPE_METADATA
	31	};
	32
a739ff3f ST	33	struct dm_verity_fec;
a739ff3f ST	34
ffa39380 ST	35	struct dm_verity {
	36	struct dm_dev *data_dev;
	37	struct dm_dev *hash_dev;
	38	struct dm_target *ti;
	39	struct dm_bufio_client *bufio;
	40	char *alg_name;
d1ac3ff0	41	struct crypto_ahash *tfm;
ffa39380 ST	42	u8 root_digest; / digest of the root block */
ffa39380 ST	43	u8 salt; / salt: its size is salt_size */
0cc37c2d	44	u8 zero_digest; / digest for a zero block */
ffa39380 ST	45	unsigned salt_size;
	46	sector_t data_start; /* data offset in 512-byte sectors */
	47	sector_t hash_start; /* hash start in blocks */
	48	sector_t data_blocks; /* the number of data blocks */
	49	sector_t hash_blocks; /* the number of hash blocks */
	50	unsigned char data_dev_block_bits; /* log2(data blocksize) */
	51	unsigned char hash_dev_block_bits; /* log2(hash blocksize) */
	52	unsigned char hash_per_block_bits; /* log2(hashes in hash block) */
	53	unsigned char levels; /* the number of tree levels */
	54	unsigned char version;
5721d4e5 NH	55	bool hash_failed:1; /* set if hash of any block failed */
5721d4e5 NH	56	bool use_tasklet:1; /* try to verify in tasklet before work-queue */
ffa39380	57	unsigned digest_size; /* digest size for the current hash algorithm */
d1ac3ff0	58	unsigned int ahash_reqsize;/* the size of temporary space for crypto */
ffa39380 ST	59	enum verity_mode mode; /* mode for handling verification errors */
	60	unsigned corrupted_errs;/* Number of errors for corrupted blocks */
	61
	62	struct workqueue_struct *verify_wq;
	63
	64	/* starting blocks for each tree level. 0 is the lowest level. */
	65	sector_t hash_level_block[DM_VERITY_MAX_LEVELS];
a739ff3f ST	66
a739ff3f ST	67	struct dm_verity_fec fec; / forward error correction */
843f38d3	68	unsigned long validated_blocks; / bitset blocks validated */
88cd3e6c JK	69
88cd3e6c JK	70	char signature_key_desc; / signature keyring reference */
ffa39380 ST	71	};
	72
	73	struct dm_verity_io {
	74	struct dm_verity *v;
	75
	76	/* original value of bio->bi_end_io */
	77	bio_end_io_t *orig_bi_end_io;
	78
	79	sector_t block;
	80	unsigned n_blocks;
5721d4e5	81	bool in_tasklet;
ffa39380 ST	82
	83	struct bvec_iter iter;
	84
	85	struct work_struct work;
5721d4e5	86	struct tasklet_struct tasklet;
ffa39380 ST	87
	88	/*
	89	* Three variably-size fields follow this struct:
	90	*
d1ac3ff0	91	* u8 hash_req[v->ahash_reqsize];
ffa39380 ST	92	* u8 real_digest[v->digest_size];
	93	* u8 want_digest[v->digest_size];
	94	*
d1ac3ff0	95	* To access them use: verity_io_hash_req(), verity_io_real_digest()
ffa39380 ST	96	* and verity_io_want_digest().
	97	*/
	98	};
	99
d1ac3ff0	100	static inline struct ahash_request verity_io_hash_req(struct dm_verity v,
ffa39380 ST	101	struct dm_verity_io *io)
ffa39380 ST	102	{
d1ac3ff0	103	return (struct ahash_request *)(io + 1);
ffa39380 ST	104	}
	105
	106	static inline u8 verity_io_real_digest(struct dm_verity v,
	107	struct dm_verity_io *io)
	108	{
d1ac3ff0	109	return (u8 *)(io + 1) + v->ahash_reqsize;
ffa39380 ST	110	}
	111
	112	static inline u8 verity_io_want_digest(struct dm_verity v,
	113	struct dm_verity_io *io)
	114	{
d1ac3ff0	115	return (u8 *)(io + 1) + v->ahash_reqsize + v->digest_size;
ffa39380 ST	116	}
ffa39380 ST	117
a739ff3f ST	118	static inline u8 verity_io_digest_end(struct dm_verity v,
	119	struct dm_verity_io *io)
	120	{
	121	return verity_io_want_digest(v, io) + v->digest_size;
	122	}
	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,
ffa39380 ST	131	const u8 data, size_t len, u8 digest);
	132
	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 MK	136	extern bool dm_is_verity_target(struct dm_target *ti);
	137	extern int dm_verity_get_root_digest(struct dm_target ti, u8 *root_digest,
	138	unsigned int *digest_size);
	139
ffa39380	140	#endif /* DM_VERITY_H */