* access behavior.
*/
-#include "dm-bufio.h"
+#include "dm-verity.h"
#include <linux/module.h>
-#include <linux/device-mapper.h>
#include <linux/reboot.h>
-#include <crypto/hash.h>
#define DM_MSG_PREFIX "verity"
#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"
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;
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.
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;
* 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,
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,
* 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;
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;
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))
--- /dev/null
+/*
+ * 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
+ *
+ * This file is released under the GPLv2.
+ */
+
+#ifndef DM_VERITY_H
+#define DM_VERITY_H
+
+#include "dm-bufio.h"
+#include <linux/device-mapper.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
+};
+
+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 */
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