dm verity: factor out structures and functions useful to separate object
Prepare for an optional verity object to make use of existing dm-verity structures and functions. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Sami Tolvanen
Mike Snitzer
Родитель
03045cbafa
Коммит
ffa393807c
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@ -14,12 +14,10 @@
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* access behavior.
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*/
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#include "dm-bufio.h"
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#include "dm-verity.h"
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#include <linux/module.h>
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#include <linux/device-mapper.h>
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#include <linux/reboot.h>
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#include <crypto/hash.h>
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#define DM_MSG_PREFIX "verity"
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@ -28,7 +26,6 @@
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#define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144
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#define DM_VERITY_MAX_LEVELS 63
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#define DM_VERITY_MAX_CORRUPTED_ERRS 100
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#define DM_VERITY_OPT_LOGGING "ignore_corruption"
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@ -40,72 +37,6 @@ static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE;
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module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR);
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enum verity_mode {
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DM_VERITY_MODE_EIO,
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DM_VERITY_MODE_LOGGING,
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DM_VERITY_MODE_RESTART
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};
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enum verity_block_type {
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DM_VERITY_BLOCK_TYPE_DATA,
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DM_VERITY_BLOCK_TYPE_METADATA
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};
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struct dm_verity {
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struct dm_dev *data_dev;
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struct dm_dev *hash_dev;
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struct dm_target *ti;
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struct dm_bufio_client *bufio;
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char *alg_name;
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struct crypto_shash *tfm;
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u8 *root_digest; /* digest of the root block */
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u8 *salt; /* salt: its size is salt_size */
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unsigned salt_size;
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sector_t data_start; /* data offset in 512-byte sectors */
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sector_t hash_start; /* hash start in blocks */
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sector_t data_blocks; /* the number of data blocks */
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sector_t hash_blocks; /* the number of hash blocks */
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unsigned char data_dev_block_bits; /* log2(data blocksize) */
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unsigned char hash_dev_block_bits; /* log2(hash blocksize) */
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unsigned char hash_per_block_bits; /* log2(hashes in hash block) */
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unsigned char levels; /* the number of tree levels */
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unsigned char version;
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unsigned digest_size; /* digest size for the current hash algorithm */
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unsigned shash_descsize;/* the size of temporary space for crypto */
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int hash_failed; /* set to 1 if hash of any block failed */
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enum verity_mode mode; /* mode for handling verification errors */
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unsigned corrupted_errs;/* Number of errors for corrupted blocks */
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struct workqueue_struct *verify_wq;
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/* starting blocks for each tree level. 0 is the lowest level. */
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sector_t hash_level_block[DM_VERITY_MAX_LEVELS];
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};
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struct dm_verity_io {
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struct dm_verity *v;
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/* original value of bio->bi_end_io */
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bio_end_io_t *orig_bi_end_io;
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sector_t block;
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unsigned n_blocks;
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struct bvec_iter iter;
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struct work_struct work;
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/*
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* Three variably-size fields follow this struct:
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*
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* u8 hash_desc[v->shash_descsize];
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* u8 real_digest[v->digest_size];
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* u8 want_digest[v->digest_size];
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*
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* To access them use: io_hash_desc(), io_real_digest() and io_want_digest().
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*/
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};
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struct dm_verity_prefetch_work {
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struct work_struct work;
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struct dm_verity *v;
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@ -113,21 +44,6 @@ struct dm_verity_prefetch_work {
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unsigned n_blocks;
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};
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static struct shash_desc *io_hash_desc(struct dm_verity *v, struct dm_verity_io *io)
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{
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return (struct shash_desc *)(io + 1);
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}
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static u8 *io_real_digest(struct dm_verity *v, struct dm_verity_io *io)
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{
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return (u8 *)(io + 1) + v->shash_descsize;
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}
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static u8 *io_want_digest(struct dm_verity *v, struct dm_verity_io *io)
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{
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return (u8 *)(io + 1) + v->shash_descsize + v->digest_size;
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}
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/*
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* Auxiliary structure appended to each dm-bufio buffer. If the value
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* hash_verified is nonzero, hash of the block has been verified.
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@ -236,8 +152,8 @@ static int verity_hash_final(struct dm_verity *v, struct shash_desc *desc,
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return r;
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}
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static int verity_hash(struct dm_verity *v, struct shash_desc *desc,
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const u8 *data, size_t len, u8 *digest)
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int verity_hash(struct dm_verity *v, struct shash_desc *desc,
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const u8 *data, size_t len, u8 *digest)
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{
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int r;
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@ -325,12 +241,12 @@ out:
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* Verify hash of a metadata block pertaining to the specified data block
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* ("block" argument) at a specified level ("level" argument).
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*
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* On successful return, io_want_digest(v, io) contains the hash value for
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* a lower tree level or for the data block (if we're at the lowest leve).
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* On successful return, verity_io_want_digest(v, io) contains the hash value
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* for a lower tree level or for the data block (if we're at the lowest level).
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*
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* If "skip_unverified" is true, unverified buffer is skipped and 1 is returned.
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* If "skip_unverified" is false, unverified buffer is hashed and verified
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* against current value of io_want_digest(v, io).
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* against current value of verity_io_want_digest(v, io).
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*/
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static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
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sector_t block, int level, bool skip_unverified,
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@ -357,13 +273,13 @@ static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
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goto release_ret_r;
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}
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r = verity_hash(v, io_hash_desc(v, io),
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r = verity_hash(v, verity_io_hash_desc(v, io),
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data, 1 << v->hash_dev_block_bits,
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io_real_digest(v, io));
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verity_io_real_digest(v, io));
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if (unlikely(r < 0))
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goto release_ret_r;
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if (likely(memcmp(io_real_digest(v, io), want_digest,
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if (likely(memcmp(verity_io_real_digest(v, io), want_digest,
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v->digest_size) == 0))
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aux->hash_verified = 1;
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else if (verity_handle_err(v,
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@ -387,8 +303,8 @@ release_ret_r:
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* Find a hash for a given block, write it to digest and verify the integrity
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* of the hash tree if necessary.
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*/
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static int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
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sector_t block, u8 *digest)
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int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
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sector_t block, u8 *digest)
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{
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int i;
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int r;
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@ -430,10 +346,10 @@ static int verity_verify_io(struct dm_verity_io *io)
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for (b = 0; b < io->n_blocks; b++) {
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int r;
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unsigned todo;
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struct shash_desc *desc = io_hash_desc(v, io);
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struct shash_desc *desc = verity_io_hash_desc(v, io);
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r = verity_hash_for_block(v, io, io->block + b,
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io_want_digest(v, io));
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verity_io_want_digest(v, io));
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if (unlikely(r < 0))
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return r;
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@ -462,12 +378,12 @@ static int verity_verify_io(struct dm_verity_io *io)
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todo -= len;
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} while (todo);
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r = verity_hash_final(v, desc, io_real_digest(v, io));
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r = verity_hash_final(v, desc, verity_io_real_digest(v, io));
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if (unlikely(r < 0))
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return r;
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if (likely(memcmp(io_real_digest(v, io),
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io_want_digest(v, io), v->digest_size) == 0))
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if (likely(memcmp(verity_io_real_digest(v, io),
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verity_io_want_digest(v, io), v->digest_size) == 0))
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continue;
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else if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA,
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io->block + b))
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@ -0,0 +1,112 @@
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/*
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* Copyright (C) 2012 Red Hat, Inc.
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* Copyright (C) 2015 Google, Inc.
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*
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* Author: Mikulas Patocka <mpatocka@redhat.com>
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*
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* Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors
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*
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* This file is released under the GPLv2.
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*/
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#ifndef DM_VERITY_H
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#define DM_VERITY_H
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#include "dm-bufio.h"
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#include <linux/device-mapper.h>
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#include <crypto/hash.h>
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#define DM_VERITY_MAX_LEVELS 63
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enum verity_mode {
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DM_VERITY_MODE_EIO,
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DM_VERITY_MODE_LOGGING,
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DM_VERITY_MODE_RESTART
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};
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enum verity_block_type {
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DM_VERITY_BLOCK_TYPE_DATA,
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DM_VERITY_BLOCK_TYPE_METADATA
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};
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struct dm_verity {
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struct dm_dev *data_dev;
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struct dm_dev *hash_dev;
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struct dm_target *ti;
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struct dm_bufio_client *bufio;
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char *alg_name;
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struct crypto_shash *tfm;
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u8 *root_digest; /* digest of the root block */
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u8 *salt; /* salt: its size is salt_size */
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unsigned salt_size;
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sector_t data_start; /* data offset in 512-byte sectors */
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sector_t hash_start; /* hash start in blocks */
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sector_t data_blocks; /* the number of data blocks */
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sector_t hash_blocks; /* the number of hash blocks */
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unsigned char data_dev_block_bits; /* log2(data blocksize) */
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unsigned char hash_dev_block_bits; /* log2(hash blocksize) */
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unsigned char hash_per_block_bits; /* log2(hashes in hash block) */
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unsigned char levels; /* the number of tree levels */
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unsigned char version;
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unsigned digest_size; /* digest size for the current hash algorithm */
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unsigned shash_descsize;/* the size of temporary space for crypto */
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int hash_failed; /* set to 1 if hash of any block failed */
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enum verity_mode mode; /* mode for handling verification errors */
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unsigned corrupted_errs;/* Number of errors for corrupted blocks */
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struct workqueue_struct *verify_wq;
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/* starting blocks for each tree level. 0 is the lowest level. */
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sector_t hash_level_block[DM_VERITY_MAX_LEVELS];
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};
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struct dm_verity_io {
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struct dm_verity *v;
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/* original value of bio->bi_end_io */
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bio_end_io_t *orig_bi_end_io;
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sector_t block;
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unsigned n_blocks;
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struct bvec_iter iter;
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struct work_struct work;
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/*
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* Three variably-size fields follow this struct:
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*
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* u8 hash_desc[v->shash_descsize];
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* u8 real_digest[v->digest_size];
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* u8 want_digest[v->digest_size];
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*
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* To access them use: verity_io_hash_desc(), verity_io_real_digest()
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* and verity_io_want_digest().
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*/
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};
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static inline struct shash_desc *verity_io_hash_desc(struct dm_verity *v,
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struct dm_verity_io *io)
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{
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return (struct shash_desc *)(io + 1);
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}
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static inline u8 *verity_io_real_digest(struct dm_verity *v,
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struct dm_verity_io *io)
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{
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return (u8 *)(io + 1) + v->shash_descsize;
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}
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static inline u8 *verity_io_want_digest(struct dm_verity *v,
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struct dm_verity_io *io)
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{
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return (u8 *)(io + 1) + v->shash_descsize + v->digest_size;
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}
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extern int verity_hash(struct dm_verity *v, struct shash_desc *desc,
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const u8 *data, size_t len, u8 *digest);
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extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
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sector_t block, u8 *digest);
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#endif /* DM_VERITY_H */
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