From ffa393807cd69656d5b6bc9d9622e205071cbab8 Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Thu, 3 Dec 2015 16:01:51 -0500 Subject: 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 Signed-off-by: Mike Snitzer --- drivers/md/dm-verity-target.c | 116 ++++++------------------------------------ drivers/md/dm-verity.h | 112 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 128 insertions(+), 100 deletions(-) create mode 100644 drivers/md/dm-verity.h diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c index b0a53c3..7e200ba 100644 --- a/drivers/md/dm-verity-target.c +++ b/drivers/md/dm-verity-target.c @@ -14,12 +14,10 @@ * access behavior. */ -#include "dm-bufio.h" +#include "dm-verity.h" #include -#include #include -#include #define DM_MSG_PREFIX "verity" @@ -28,7 +26,6 @@ #define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144 -#define DM_VERITY_MAX_LEVELS 63 #define DM_VERITY_MAX_CORRUPTED_ERRS 100 #define DM_VERITY_OPT_LOGGING "ignore_corruption" @@ -40,72 +37,6 @@ static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE; module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR); -enum verity_mode { - DM_VERITY_MODE_EIO, - DM_VERITY_MODE_LOGGING, - DM_VERITY_MODE_RESTART -}; - -enum verity_block_type { - DM_VERITY_BLOCK_TYPE_DATA, - DM_VERITY_BLOCK_TYPE_METADATA -}; - -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 *tfm; - u8 *root_digest; /* digest of the root block */ - u8 *salt; /* salt: its size is salt_size */ - 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; - unsigned digest_size; /* digest size for the current hash algorithm */ - unsigned shash_descsize;/* the size of temporary space for crypto */ - int hash_failed; /* set to 1 if hash of any block failed */ - 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_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; - - struct bvec_iter iter; - - struct work_struct work; - - /* - * Three variably-size fields follow this struct: - * - * u8 hash_desc[v->shash_descsize]; - * u8 real_digest[v->digest_size]; - * u8 want_digest[v->digest_size]; - * - * To access them use: io_hash_desc(), io_real_digest() and io_want_digest(). - */ -}; - struct dm_verity_prefetch_work { struct work_struct work; struct dm_verity *v; @@ -113,21 +44,6 @@ struct dm_verity_prefetch_work { unsigned n_blocks; }; -static struct shash_desc *io_hash_desc(struct dm_verity *v, struct dm_verity_io *io) -{ - return (struct shash_desc *)(io + 1); -} - -static u8 *io_real_digest(struct dm_verity *v, struct dm_verity_io *io) -{ - return (u8 *)(io + 1) + v->shash_descsize; -} - -static u8 *io_want_digest(struct dm_verity *v, struct dm_verity_io *io) -{ - return (u8 *)(io + 1) + v->shash_descsize + v->digest_size; -} - /* * Auxiliary structure appended to each dm-bufio buffer. If the value * hash_verified is nonzero, hash of the block has been verified. @@ -236,8 +152,8 @@ static int verity_hash_final(struct dm_verity *v, struct shash_desc *desc, return r; } -static int verity_hash(struct dm_verity *v, struct shash_desc *desc, - const u8 *data, size_t len, u8 *digest) +int verity_hash(struct dm_verity *v, struct shash_desc *desc, + const u8 *data, size_t len, u8 *digest) { int r; @@ -325,12 +241,12 @@ out: * Verify hash of a metadata block pertaining to the specified data block * ("block" argument) at a specified level ("level" argument). * - * On successful return, io_want_digest(v, io) contains the hash value for - * a lower tree level or for the data block (if we're at the lowest leve). + * On successful return, verity_io_want_digest(v, io) contains the hash value + * for a lower tree level or for the data block (if we're at the lowest level). * * If "skip_unverified" is true, unverified buffer is skipped and 1 is returned. * If "skip_unverified" is false, unverified buffer is hashed and verified - * against current value of io_want_digest(v, io). + * against current value of verity_io_want_digest(v, io). */ static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io, sector_t block, int level, bool skip_unverified, @@ -357,13 +273,13 @@ static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io, goto release_ret_r; } - r = verity_hash(v, io_hash_desc(v, io), + r = verity_hash(v, verity_io_hash_desc(v, io), data, 1 << v->hash_dev_block_bits, - io_real_digest(v, io)); + verity_io_real_digest(v, io)); if (unlikely(r < 0)) goto release_ret_r; - if (likely(memcmp(io_real_digest(v, io), want_digest, + if (likely(memcmp(verity_io_real_digest(v, io), want_digest, v->digest_size) == 0)) aux->hash_verified = 1; else if (verity_handle_err(v, @@ -387,8 +303,8 @@ release_ret_r: * Find a hash for a given block, write it to digest and verify the integrity * of the hash tree if necessary. */ -static int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, - sector_t block, u8 *digest) +int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, + sector_t block, u8 *digest) { int i; int r; @@ -430,10 +346,10 @@ static int verity_verify_io(struct dm_verity_io *io) for (b = 0; b < io->n_blocks; b++) { int r; unsigned todo; - struct shash_desc *desc = io_hash_desc(v, io); + struct shash_desc *desc = verity_io_hash_desc(v, io); r = verity_hash_for_block(v, io, io->block + b, - io_want_digest(v, io)); + verity_io_want_digest(v, io)); if (unlikely(r < 0)) return r; @@ -462,12 +378,12 @@ static int verity_verify_io(struct dm_verity_io *io) todo -= len; } while (todo); - r = verity_hash_final(v, desc, io_real_digest(v, io)); + r = verity_hash_final(v, desc, verity_io_real_digest(v, io)); if (unlikely(r < 0)) return r; - if (likely(memcmp(io_real_digest(v, io), - io_want_digest(v, io), v->digest_size) == 0)) + if (likely(memcmp(verity_io_real_digest(v, io), + verity_io_want_digest(v, io), v->digest_size) == 0)) continue; else if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA, io->block + b)) diff --git a/drivers/md/dm-verity.h b/drivers/md/dm-verity.h new file mode 100644 index 0000000..c7ad4fd --- /dev/null +++ b/drivers/md/dm-verity.h @@ -0,0 +1,112 @@ +/* + * Copyright (C) 2012 Red Hat, Inc. + * Copyright (C) 2015 Google, Inc. + * + * Author: Mikulas Patocka + * + * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors + * + * This file is released under the GPLv2. + */ + +#ifndef DM_VERITY_H +#define DM_VERITY_H + +#include "dm-bufio.h" +#include +#include + +#define DM_VERITY_MAX_LEVELS 63 + +enum verity_mode { + DM_VERITY_MODE_EIO, + DM_VERITY_MODE_LOGGING, + DM_VERITY_MODE_RESTART +}; + +enum verity_block_type { + DM_VERITY_BLOCK_TYPE_DATA, + DM_VERITY_BLOCK_TYPE_METADATA +}; + +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 *tfm; + u8 *root_digest; /* digest of the root block */ + u8 *salt; /* salt: its size is salt_size */ + 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; + unsigned digest_size; /* digest size for the current hash algorithm */ + unsigned shash_descsize;/* the size of temporary space for crypto */ + int hash_failed; /* set to 1 if hash of any block failed */ + 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_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; + + struct bvec_iter iter; + + struct work_struct work; + + /* + * Three variably-size fields follow this struct: + * + * u8 hash_desc[v->shash_descsize]; + * u8 real_digest[v->digest_size]; + * u8 want_digest[v->digest_size]; + * + * To access them use: verity_io_hash_desc(), verity_io_real_digest() + * and verity_io_want_digest(). + */ +}; + +static inline struct shash_desc *verity_io_hash_desc(struct dm_verity *v, + struct dm_verity_io *io) +{ + return (struct shash_desc *)(io + 1); +} + +static inline u8 *verity_io_real_digest(struct dm_verity *v, + struct dm_verity_io *io) +{ + return (u8 *)(io + 1) + v->shash_descsize; +} + +static inline u8 *verity_io_want_digest(struct dm_verity *v, + struct dm_verity_io *io) +{ + return (u8 *)(io + 1) + v->shash_descsize + v->digest_size; +} + +extern int verity_hash(struct dm_verity *v, struct shash_desc *desc, + 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); + +#endif /* DM_VERITY_H */ -- cgit v1.1