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Diffstat (limited to 'drivers/md/dm-verity.h')
| -rw-r--r-- | drivers/md/dm-verity.h | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/drivers/md/dm-verity.h b/drivers/md/dm-verity.h new file mode 100644 index 000000000..e104a651c --- /dev/null +++ b/drivers/md/dm-verity.h @@ -0,0 +1,148 @@ +/* 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> +#include <crypto/sha2.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_shash *shash_tfm; + u8 *root_digest; /* digest of the root block */ + u8 *salt; /* salt: its size is salt_size */ + union { + struct sha256_ctx *sha256; /* for use_sha256_lib=1 */ + u8 *shash; /* for use_sha256_lib=0 */ + } initial_hashstate; /* salted initial state, if version >= 1 */ + 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 hash_start; /* index of first hash block on hash_dev */ + sector_t hash_end; /* 1 + index of last hash block on hash dev */ + sector_t data_blocks; /* the number of data 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 */ + bool use_sha256_lib:1; /* use SHA-256 library instead of generic crypto API */ + bool use_sha256_finup_2x:1; /* use interleaved hashing optimization */ + unsigned int digest_size; /* digest size for the current hash algorithm */ + enum verity_mode mode; /* mode for handling verification errors */ + enum verity_mode error_mode;/* mode for handling I/O errors */ + atomic_t 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 pending_block { + void *data; + sector_t blkno; + u8 want_digest[HASH_MAX_DIGESTSIZE]; + u8 real_digest[HASH_MAX_DIGESTSIZE]; +}; + +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; + bool had_mismatch; + +#ifdef CONFIG_DM_VERITY_FEC + struct dm_verity_fec_io *fec_io; +#endif + + struct work_struct work; + + u8 tmp_digest[HASH_MAX_DIGESTSIZE]; + + /* + * This is the queue of data blocks that are pending verification. When + * the crypto layer supports interleaved hashing, we allow multiple + * blocks to be queued up in order to utilize it. This can improve + * performance significantly vs. sequential hashing of each block. + */ + int num_pending; + struct pending_block pending_blocks[2]; + + /* + * Temporary space for hashing. Either sha256 or shash is used, + * depending on the value of use_sha256_lib. If shash is used, + * then this field is variable-length, with total size + * sizeof(struct shash_desc) + crypto_shash_descsize(shash_tfm). + * For this reason, this field must be the end of the struct. + */ + union { + struct sha256_ctx sha256; + struct shash_desc shash; + } hash_ctx; +}; + +extern int verity_hash(struct dm_verity *v, struct dm_verity_io *io, + 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_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 */ |