- 根目录:
- drivers
- md
- dm-verity-target.c
/*
* Copyright (C) 2012 Red Hat, 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.
*
* In the file "/sys/module/dm_verity/parameters/prefetch_cluster" you can set
* default prefetch value. Data are read in "prefetch_cluster" chunks from the
* hash device. Setting this greatly improves performance when data and hash
* are on the same disk on different partitions on devices with poor random
* access behavior.
*/
#include "dm-verity.h"
#include "dm-verity-fec.h"
#include <linux/module.h>
#include <linux/reboot.h>
#define DM_MSG_PREFIX "verity"
#define DM_VERITY_ENV_LENGTH 42
#define DM_VERITY_ENV_VAR_NAME "DM_VERITY_ERR_BLOCK_NR"
#define DM_VERITY_MEMPOOL_SIZE 4
#define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144
#define DM_VERITY_MAX_CORRUPTED_ERRS 100
#define DM_VERITY_OPT_LOGGING "ignore_corruption"
#define DM_VERITY_OPT_RESTART "restart_on_corruption"
#define DM_VERITY_OPT_IGN_ZEROES "ignore_zero_blocks"
#define DM_VERITY_OPTS_MAX (2 + DM_VERITY_OPTS_FEC)
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);
struct dm_verity_prefetch_work {
struct work_struct work;
struct dm_verity *v;
sector_t block;
unsigned n_blocks;
};
/*
* Auxiliary structure appended to each dm-bufio buffer. If the value
* hash_verified is nonzero, hash of the block has been verified.
*
* The variable hash_verified is set to 0 when allocating the buffer, then
* it can be changed to 1 and it is never reset to 0 again.
*
* There is no lock around this value, a race condition can at worst cause
* that multiple processes verify the hash of the same buffer simultaneously
* and write 1 to hash_verified simultaneously.
* This condition is harmless, so we don't need locking.
*/
struct buffer_aux {
int hash_verified;
};
/*
* Initialize struct buffer_aux for a freshly created buffer.
*/
static void dm_bufio_alloc_callback(struct dm_buffer *buf)
{
struct buffer_aux *aux = dm_bufio_get_aux_data(buf);
aux->hash_verified = 0;
}
/*
* Translate input sector number to the sector number on the target device.
*/
static sector_t verity_map_sector(struct dm_verity *v, sector_t bi_sector)
{
return v->data_start + dm_target_offset(v->ti, bi_sector);
}
/*
* Return hash position of a specified block at a specified tree level
* (0 is the lowest level).
* The lowest "hash_per_block_bits"-bits of the result denote hash position
* inside a hash block. The remaining bits denote location of the hash block.
*/
static sector_t verity_position_at_level(struct dm_verity *v, sector_t block,
int level)
{
return block >> (level * v->hash_per_block_bits);
}
/*
* Wrapper for crypto_shash_init, which handles verity salting.
*/
static int verity_hash_init(struct dm_verity *v, struct shash_desc *desc)
{
int r;
desc->tfm = v->tfm;
desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
r = crypto_shash_init(desc);
if (unlikely(r < 0)) {
DMERR("crypto_shash_init failed: %d", r);
return r;
}
if (likely(v->version >= 1)) {
r = crypto_shash_update(desc, v->salt, v->salt_size);
if (unlikely(r < 0)) {
DMERR("crypto_shash_update failed: %d", r);
return r;
}
}
return 0;
}
static int verity_hash_update(struct dm_verity *v, struct shash_desc *desc,
const u8 *data, size_t len)
{
int r = crypto_shash_update(desc, data, len);
if (unlikely(r < 0))
DMERR("crypto_shash_update failed: %d", r);
return r;
}
static int verity_hash_final(struct dm_verity *v, struct shash_desc *desc,
u8 *digest)
{
int r;
if (unlikely(!v->version)) {
r = crypto_shash_update(desc, v->salt, v->salt_size);
if (r < 0) {
DMERR("crypto_shash_update failed: %d", r);
return r;
}
}
r = crypto_shash_final(desc, digest);
if (unlikely(r < 0))
DMERR("crypto_shash_final failed: %d", r);
return r;
}
int verity_hash(struct dm_verity *v, struct shash_desc *desc,
const u8 *data, size_t len, u8 *digest)
{
int r;
r = verity_hash_init(v, desc);
if (unlikely(r < 0))
return r;
r = verity_hash_update(v, desc, data, len);
if (unlikely(r < 0))
return r;
return verity_hash_final(v, desc, digest);
}
static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level,
sector_t *hash_block, unsigned *offset)
{
sector_t position = verity_position_at_level(v, block, level);
unsigned idx;
*hash_block = v->hash_level_block[level] + (position >> v->hash_per_block_bits);
if (!offset)
return;
idx = position & ((1 << v->hash_per_block_bits) - 1);
if (!v->version)
*offset = idx * v->digest_size;
else
*offset = idx << (v->hash_dev_block_bits - v->hash_per_block_bits);
}
/*
* Handle verification errors.
*/
static int verity_handle_err(struct dm_verity *v, enum verity_block_type type,
unsigned long long block)
{
char verity_env[DM_VERITY_ENV_LENGTH];
char *envp[] = { verity_env, NULL };
const char *type_str = "";
struct mapped_device *md = dm_table_get_md(v->ti->table);
/* Corruption should be visible in device status in all modes */
v->hash_failed = 1;
if (v->corrupted_errs >= DM_VERITY_MAX_CORRUPTED_ERRS)
goto out;
v->corrupted_errs++;
switch (type) {
case DM_VERITY_BLOCK_TYPE_DATA:
type_str = "data";
break;
case DM_VERITY_BLOCK_TYPE_METADATA:
type_str = "metadata";
break;
default:
BUG();
}
DMERR("%s: %s block %llu is corrupted", v->data_dev->name, type_str,
block);
if (v->corrupted_errs == DM_VERITY_MAX_CORRUPTED_ERRS)
DMERR("%s: reached maximum errors", v->data_dev->name);
snprintf(verity_env, DM_VERITY_ENV_LENGTH, "%s=%d,%llu",
DM_VERITY_ENV_VAR_NAME, type, block);
kobject_uevent_env(&disk_to_dev(dm_disk(md))->kobj, KOBJ_CHANGE, envp);
out:
if (v->mode == DM_VERITY_MODE_LOGGING)
return 0;
if (v->mode == DM_VERITY_MODE_RESTART)
kernel_restart("dm-verity device corrupted");
return 1;
}
/*
* Verify hash of a metadata block pertaining to the specified data block
* ("block" argument) at a specified level ("level" argument).
*
* 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 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,
u8 *want_digest)
{
struct dm_buffer *buf;
struct buffer_aux *aux;
u8 *data;
int r;
sector_t hash_block;
unsigned offset;
verity_hash_at_level(v, block, level, &hash_block, &offset);
data = dm_bufio_read(v->bufio, hash_block, &buf);
if (IS_ERR(data))
return PTR_ERR(data);
aux = dm_bufio_get_aux_data(buf);
if (!aux->hash_verified) {
if (skip_unverified) {
r = 1;
goto release_ret_r;
}
r = verity_hash(v, verity_io_hash_desc(v, io),
data, 1 << v->hash_dev_block_bits,
verity_io_real_digest(v, io));
if (unlikely(r < 0))
goto release_ret_r;
if (likely(memcmp(verity_io_real_digest(v, io), want_digest,
v->digest_size) == 0))
aux->hash_verified = 1;
else if (verity_fec_decode(v, io,
DM_VERITY_BLOCK_TYPE_METADATA,
hash_block, data, 0, 0) == 0)
aux->hash_verified = 1;
else if (verity_handle_err(v,
DM_VERITY_BLOCK_TYPE_METADATA,
hash_block)) {
r = -EIO;
goto release_ret_r;
}
}
data += offset;
memcpy(want_digest, data, v->digest_size);
r = 0;
release_ret_r:
dm_bufio_release(buf);
return r;
}
/*
* Find a hash for a given block, write it to digest and verify the integrity
* of the hash tree if necessary.
*/
int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
sector_t block, u8 *digest, bool *is_zero)
{
int r = 0, i;
if (likely(v->levels)) {
/*
* First, we try to get the requested hash for
* the current block. If the hash block itself is
* verified, zero is returned. If it isn't, this
* function returns 1 and we fall back to whole
* chain verification.
*/
r = verity_verify_level(v, io, block, 0, true, digest);
if (likely(r <= 0))
goto out;
}
memcpy(digest, v->root_digest, v->digest_size);
for (i = v->levels - 1; i >= 0; i--) {
r = verity_verify_level(v, io, block, i, false, digest);
if (unlikely(r))
goto out;
}
out:
if (!r && v->zero_digest)
*is_zero = !memcmp(v->zero_digest, digest, v->digest_size);
else
*is_zero = false;
return r;
}
/*
* Calls function process for 1 << v->data_dev_block_bits bytes in io->io_vec
* starting from (vector, offset).
*/
int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
unsigned *vector, unsigned *offset,
int (*process)(struct dm_verity *v,
struct dm_verity_io *io,
u8 *data, size_t len))
{
unsigned todo = 1 << v->data_dev_block_bits;
do {
int r;
struct bio_vec *bv;
u8 *page;
unsigned len;
BUG_ON(*vector >= io->io_vec_size);
bv = &io->io_vec[*vector];
page = kmap_atomic(bv->bv_page);
len = bv->bv_len - *offset;
if (likely(len >= todo))
len = todo;
r = process(v, io, page + bv->bv_offset + *offset, len);
kunmap_atomic(page);
if (r < 0)
return r;
*offset += len;
if (likely(*offset == bv->bv_len)) {
*offset = 0;
(*vector)++;
}
todo -= len;
} while (todo);
return 0;
}
static int verity_bv_hash_update(struct dm_verity *v, struct dm_verity_io *io,
u8 *data, size_t len)
{
return verity_hash_update(v, verity_io_hash_desc(v, io), data, len);
}
static int verity_bv_zero(struct dm_verity *v, struct dm_verity_io *io,
u8 *data, size_t len)
{
memset(data, 0, len);
return 0;
}
/*
* Verify one "dm_verity_io" structure.
*/
static int verity_verify_io(struct dm_verity_io *io)
{
bool is_zero;
struct dm_verity *v = io->v;
unsigned b;
unsigned vector = 0, offset = 0;
unsigned start_vector, start_offset;
for (b = 0; b < io->n_blocks; b++) {
int r;
struct shash_desc *desc = verity_io_hash_desc(v, io);
r = verity_hash_for_block(v, io, io->block + b,
verity_io_want_digest(v, io),
&is_zero);
if (unlikely(r < 0))
return r;
if (is_zero) {
/*
* If we expect a zero block, don't validate, just
* return zeros.
*/
r = verity_for_bv_block(v, io, &vector, &offset,
verity_bv_zero);
if (unlikely(r < 0))
return r;
continue;
}
r = verity_hash_init(v, desc);
if (unlikely(r < 0))
return r;
start_vector = vector;
start_offset = offset;
r = verity_for_bv_block(v, io, &vector, &offset,
verity_bv_hash_update);
if (unlikely(r < 0))
return r;
r = verity_hash_final(v, desc, verity_io_real_digest(v, io));
if (unlikely(r < 0))
return r;
if (likely(memcmp(verity_io_real_digest(v, io),
verity_io_want_digest(v, io), v->digest_size) == 0))
continue;
else if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_DATA,
io->block + b, NULL, start_vector, start_offset) == 0)
continue;
else if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA,
io->block + b))
return -EIO;
}
BUG_ON(vector != io->io_vec_size);
BUG_ON(offset);
return 0;
}
/*
* End one "io" structure with a given error.
*/
static void verity_finish_io(struct dm_verity_io *io, int error)
{
struct dm_verity *v = io->v;
struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_bio_data_size);
bio->bi_end_io = io->orig_bi_end_io;
bio->bi_private = io->orig_bi_private;
if (io->io_vec != io->io_vec_inline)
mempool_free(io->io_vec, v->vec_mempool);
verity_fec_finish_io(io, error);
bio_endio(bio, error);
}
static void verity_work(struct work_struct *w)
{
struct dm_verity_io *io = container_of(w, struct dm_verity_io, work);
verity_finish_io(io, verity_verify_io(io));
}
static void verity_end_io(struct bio *bio, int error)
{
struct dm_verity_io *io = bio->bi_private;
if (error && !verity_fec_is_enabled(io->v)) {
verity_finish_io(io, error);
return;
}
INIT_WORK(&io->work, verity_work);
queue_work(io->v->verify_wq, &io->work);
}
/*
* Prefetch buffers for the specified io.
* The root buffer is not prefetched, it is assumed that it will be cached
* all the time.
*/
static void verity_prefetch_io(struct work_struct *work)
{
struct dm_verity_prefetch_work *pw =
container_of(work, struct dm_verity_prefetch_work, work);
struct dm_verity *v = pw->v;
int i;
for (i = v->levels - 2; i >= 0; i--) {
sector_t hash_block_start;
sector_t hash_block_end;
verity_hash_at_level(v, pw->block, i, &hash_block_start, NULL);
verity_hash_at_level(v, pw->block + pw->n_blocks - 1, i, &hash_block_end, NULL);
if (!i) {
unsigned cluster = ACCESS_ONCE(dm_verity_prefetch_cluster);
cluster >>= v->data_dev_block_bits;
if (unlikely(!cluster))
goto no_prefetch_cluster;
if (unlikely(cluster & (cluster - 1)))
cluster = 1 << __fls(cluster);
hash_block_start &= ~(sector_t)(cluster - 1);
hash_block_end |= cluster - 1;
if (unlikely(hash_block_end >= v->hash_blocks))
hash_block_end = v->hash_blocks - 1;
}
no_prefetch_cluster:
dm_bufio_prefetch(v->bufio, hash_block_start,
hash_block_end - hash_block_start + 1);
}
kfree(pw);
}
static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io)
{
struct dm_verity_prefetch_work *pw;
pw = kmalloc(sizeof(struct dm_verity_prefetch_work),
GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
if (!pw)
return;
INIT_WORK(&pw->work, verity_prefetch_io);
pw->v = v;
pw->block = io->block;
pw->n_blocks = io->n_blocks;
queue_work(v->verify_wq, &pw->work);
}
/*
* Bio map function. It allocates dm_verity_io structure and bio vector and
* fills them. Then it issues prefetches and the I/O.
*/
int verity_map(struct dm_target *ti, struct bio *bio)
{
struct dm_verity *v = ti->private;
struct dm_verity_io *io;
bio->bi_bdev = v->data_dev->bdev;
bio->bi_sector = verity_map_sector(v, bio->bi_sector);
if (((unsigned)bio->bi_sector | bio_sectors(bio)) &
((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) {
DMERR_LIMIT("unaligned io");
return -EIO;
}
if (bio_end_sector(bio) >>
(v->data_dev_block_bits - SECTOR_SHIFT) > v->data_blocks) {
DMERR_LIMIT("io out of range");
return -EIO;
}
if (bio_data_dir(bio) == WRITE)
return -EIO;
io = dm_per_bio_data(bio, ti->per_bio_data_size);
io->v = v;
io->orig_bi_end_io = bio->bi_end_io;
io->orig_bi_private = bio->bi_private;
io->block = bio->bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT);
io->n_blocks = bio->bi_size >> v->data_dev_block_bits;
bio->bi_end_io = verity_end_io;
bio->bi_private = io;
io->io_vec_size = bio_segments(bio);
if (io->io_vec_size < DM_VERITY_IO_VEC_INLINE)
io->io_vec = io->io_vec_inline;
else
io->io_vec = mempool_alloc(v->vec_mempool, GFP_NOIO);
memcpy(io->io_vec, bio_iovec(bio),
io->io_vec_size * sizeof(struct bio_vec));
verity_fec_init_io(io);
verity_submit_prefetch(v, io);
generic_make_request(bio);
return DM_MAPIO_SUBMITTED;
}
/*
* Status: V (valid) or C (corruption found)
*/
void verity_status(struct dm_target *ti, status_type_t type,
unsigned status_flags, char *result, unsigned maxlen)
{
struct dm_verity *v = ti->private;
unsigned args = 0;
unsigned sz = 0;
unsigned x;
switch (type) {
case STATUSTYPE_INFO:
DMEMIT("%c", v->hash_failed ? 'C' : 'V');
break;
case STATUSTYPE_TABLE:
DMEMIT("%u %s %s %u %u %llu %llu %s ",
v->version,
v->data_dev->name,
v->hash_dev->name,
1 << v->data_dev_block_bits,
1 << v->hash_dev_block_bits,
(unsigned long long)v->data_blocks,
(unsigned long long)v->hash_start,
v->alg_name
);
for (x = 0; x < v->digest_size; x++)
DMEMIT("%02x", v->root_digest[x]);
DMEMIT(" ");
if (!v->salt_size)
DMEMIT("-");
else
for (x = 0; x < v->salt_size; x++)
DMEMIT("%02x", v->salt[x]);
if (v->mode != DM_VERITY_MODE_EIO)
args++;
if (verity_fec_is_enabled(v))
args += DM_VERITY_OPTS_FEC;
if (v->zero_digest)
args++;
if (!args)
return;
DMEMIT(" %u", args);
if (v->mode != DM_VERITY_MODE_EIO) {
DMEMIT(" ");
switch (v->mode) {
case DM_VERITY_MODE_LOGGING:
DMEMIT(DM_VERITY_OPT_LOGGING);
break;
case DM_VERITY_MODE_RESTART:
DMEMIT(DM_VERITY_OPT_RESTART);
break;
default:
BUG();
}
}
if (v->zero_digest)
DMEMIT(" " DM_VERITY_OPT_IGN_ZEROES);
sz = verity_fec_status_table(v, sz, result, maxlen);
break;
}
}
int verity_ioctl(struct dm_target *ti, unsigned cmd,
unsigned long arg)
{
struct dm_verity *v = ti->private;
int r = 0;
if (v->data_start ||
ti->len != i_size_read(v->data_dev->bdev->bd_inode) >> SECTOR_SHIFT)
r = scsi_verify_blk_ioctl(NULL, cmd);
return r ? : __blkdev_driver_ioctl(v->data_dev->bdev, v->data_dev->mode,
cmd, arg);
}
int verity_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
struct bio_vec *biovec, int max_size)
{
struct dm_verity *v = ti->private;
struct request_queue *q = bdev_get_queue(v->data_dev->bdev);
if (!q->merge_bvec_fn)
return max_size;
bvm->bi_bdev = v->data_dev->bdev;
bvm->bi_sector = verity_map_sector(v, bvm->bi_sector);
return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
}
int verity_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
struct dm_verity *v = ti->private;
return fn(ti, v->data_dev, v->data_start, ti->len, data);
}
void verity_io_hints(struct dm_target *ti, struct queue_limits *limits)
{
struct dm_verity *v = ti->private;
if (limits->logical_block_size < 1 << v->data_dev_block_bits)
limits->logical_block_size = 1 << v->data_dev_block_bits;
if (limits->physical_block_size < 1 << v->data_dev_block_bits)
limits->physical_block_size = 1 << v->data_dev_block_bits;
blk_limits_io_min(limits, limits->logical_block_size);
}
void verity_dtr(struct dm_target *ti)
{
struct dm_verity *v = ti->private;
if (v->verify_wq)
destroy_workqueue(v->verify_wq);
if (v->vec_mempool)
mempool_destroy(v->vec_mempool);
if (v->bufio)
dm_bufio_client_destroy(v->bufio);
kfree(v->salt);
kfree(v->root_digest);
kfree(v->zero_digest);
if (v->tfm)
crypto_free_shash(v->tfm);
kfree(v->alg_name);
if (v->hash_dev)
dm_put_device(ti, v->hash_dev);
if (v->data_dev)
dm_put_device(ti, v->data_dev);
verity_fec_dtr(v);
kfree(v);
}
static int verity_alloc_zero_digest(struct dm_verity *v)
{
int r = -ENOMEM;
struct shash_desc *desc;
u8 *zero_data;
v->zero_digest = kmalloc(v->digest_size, GFP_KERNEL);
if (!v->zero_digest)
return r;
desc = kmalloc(v->shash_descsize, GFP_KERNEL);
if (!desc)
return r; /* verity_dtr will free zero_digest */
zero_data = kzalloc(1 << v->data_dev_block_bits, GFP_KERNEL);
if (!zero_data)
goto out;
r = verity_hash(v, desc, zero_data, 1 << v->data_dev_block_bits,
v->zero_digest);
out:
kfree(desc);
kfree(zero_data);
return r;
}
static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v)
{
int r;
unsigned argc;
struct dm_target *ti = v->ti;
const char *arg_name;
static struct dm_arg _args[] = {
{0, DM_VERITY_OPTS_MAX, "Invalid number of feature args"},
};
r = dm_read_arg_group(_args, as, &argc, &ti->error);
if (r)
return -EINVAL;
if (!argc)
return 0;
do {
arg_name = dm_shift_arg(as);
argc--;
if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING)) {
v->mode = DM_VERITY_MODE_LOGGING;
continue;
} else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART)) {
v->mode = DM_VERITY_MODE_RESTART;
continue;
} else if (!strcasecmp(arg_name, DM_VERITY_OPT_IGN_ZEROES)) {
r = verity_alloc_zero_digest(v);
if (r) {
ti->error = "Cannot allocate zero digest";
return r;
}
continue;
} else if (verity_is_fec_opt_arg(arg_name)) {
r = verity_fec_parse_opt_args(as, v, &argc, arg_name);
if (r)
return r;
continue;
}
ti->error = "Unrecognized verity feature request";
return -EINVAL;
} while (argc && !r);
return r;
}
/*
* Target parameters:
* <version> The current format is version 1.
* Vsn 0 is compatible with original Chromium OS releases.
* <data device>
* <hash device>
* <data block size>
* <hash block size>
* <the number of data blocks>
* <hash start block>
* <algorithm>
* <digest>
* <salt> Hex string or "-" if no salt.
*/
int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
{
struct dm_verity *v;
struct dm_arg_set as;
unsigned int num;
unsigned long long num_ll;
int r;
int i;
sector_t hash_position;
char dummy;
v = kzalloc(sizeof(struct dm_verity), GFP_KERNEL);
if (!v) {
ti->error = "Cannot allocate verity structure";
return -ENOMEM;
}
ti->private = v;
v->ti = ti;
r = verity_fec_ctr_alloc(v);
if (r)
goto bad;
if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) {
ti->error = "Device must be readonly";
r = -EINVAL;
goto bad;
}
if (argc < 10) {
ti->error = "Not enough arguments";
r = -EINVAL;
goto bad;
}
if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 ||
num > 1) {
ti->error = "Invalid version";
r = -EINVAL;
goto bad;
}
v->version = num;
r = dm_get_device(ti, argv[1], FMODE_READ, &v->data_dev);
if (r) {
ti->error = "Data device lookup failed";
goto bad;
}
r = dm_get_device(ti, argv[2], FMODE_READ, &v->hash_dev);
if (r) {
ti->error = "Data device lookup failed";
goto bad;
}
if (sscanf(argv[3], "%u%c", &num, &dummy) != 1 ||
!num || (num & (num - 1)) ||
num < bdev_logical_block_size(v->data_dev->bdev) ||
num > PAGE_SIZE) {
ti->error = "Invalid data device block size";
r = -EINVAL;
goto bad;
}
v->data_dev_block_bits = __ffs(num);
if (sscanf(argv[4], "%u%c", &num, &dummy) != 1 ||
!num || (num & (num - 1)) ||
num < bdev_logical_block_size(v->hash_dev->bdev) ||
num > INT_MAX) {
ti->error = "Invalid hash device block size";
r = -EINVAL;
goto bad;
}
v->hash_dev_block_bits = __ffs(num);
if (sscanf(argv[5], "%llu%c", &num_ll, &dummy) != 1 ||
(sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT))
>> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll) {
ti->error = "Invalid data blocks";
r = -EINVAL;
goto bad;
}
v->data_blocks = num_ll;
if (ti->len > (v->data_blocks << (v->data_dev_block_bits - SECTOR_SHIFT))) {
ti->error = "Data device is too small";
r = -EINVAL;
goto bad;
}
if (sscanf(argv[6], "%llu%c", &num_ll, &dummy) != 1 ||
(sector_t)(num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT))
>> (v->hash_dev_block_bits - SECTOR_SHIFT) != num_ll) {
ti->error = "Invalid hash start";
r = -EINVAL;
goto bad;
}
v->hash_start = num_ll;
v->alg_name = kstrdup(argv[7], GFP_KERNEL);
if (!v->alg_name) {
ti->error = "Cannot allocate algorithm name";
r = -ENOMEM;
goto bad;
}
v->tfm = crypto_alloc_shash(v->alg_name, 0, 0);
if (IS_ERR(v->tfm)) {
ti->error = "Cannot initialize hash function";
r = PTR_ERR(v->tfm);
v->tfm = NULL;
goto bad;
}
v->digest_size = crypto_shash_digestsize(v->tfm);
if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) {
ti->error = "Digest size too big";
r = -EINVAL;
goto bad;
}
v->shash_descsize =
sizeof(struct shash_desc) + crypto_shash_descsize(v->tfm);
v->root_digest = kmalloc(v->digest_size, GFP_KERNEL);
if (!v->root_digest) {
ti->error = "Cannot allocate root digest";
r = -ENOMEM;
goto bad;
}
if (strlen(argv[8]) != v->digest_size * 2 ||
hex2bin(v->root_digest, argv[8], v->digest_size)) {
ti->error = "Invalid root digest";
r = -EINVAL;
goto bad;
}
if (strcmp(argv[9], "-")) {
v->salt_size = strlen(argv[9]) / 2;
v->salt = kmalloc(v->salt_size, GFP_KERNEL);
if (!v->salt) {
ti->error = "Cannot allocate salt";
r = -ENOMEM;
goto bad;
}
if (strlen(argv[9]) != v->salt_size * 2 ||
hex2bin(v->salt, argv[9], v->salt_size)) {
ti->error = "Invalid salt";
r = -EINVAL;
goto bad;
}
}
argv += 10;
argc -= 10;
/* Optional parameters */
if (argc) {
as.argc = argc;
as.argv = argv;
r = verity_parse_opt_args(&as, v);
if (r < 0)
goto bad;
}
v->hash_per_block_bits =
__fls((1 << v->hash_dev_block_bits) / v->digest_size);
v->levels = 0;
if (v->data_blocks)
while (v->hash_per_block_bits * v->levels < 64 &&
(unsigned long long)(v->data_blocks - 1) >>
(v->hash_per_block_bits * v->levels))
v->levels++;
if (v->levels > DM_VERITY_MAX_LEVELS) {
ti->error = "Too many tree levels";
r = -E2BIG;
goto bad;
}
hash_position = v->hash_start;
for (i = v->levels - 1; i >= 0; i--) {
sector_t s;
v->hash_level_block[i] = hash_position;
s = (v->data_blocks + ((sector_t)1 << ((i + 1) * v->hash_per_block_bits)) - 1)
>> ((i + 1) * v->hash_per_block_bits);
if (hash_position + s < hash_position) {
ti->error = "Hash device offset overflow";
r = -E2BIG;
goto bad;
}
hash_position += s;
}
v->hash_blocks = hash_position;
v->bufio = dm_bufio_client_create(v->hash_dev->bdev,
1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux),
dm_bufio_alloc_callback, NULL);
if (IS_ERR(v->bufio)) {
ti->error = "Cannot initialize dm-bufio";
r = PTR_ERR(v->bufio);
v->bufio = NULL;
goto bad;
}
if (dm_bufio_get_device_size(v->bufio) < v->hash_blocks) {
ti->error = "Hash device is too small";
r = -E2BIG;
goto bad;
}
v->vec_mempool = mempool_create_kmalloc_pool(DM_VERITY_MEMPOOL_SIZE,
BIO_MAX_PAGES * sizeof(struct bio_vec));
if (!v->vec_mempool) {
ti->error = "Cannot allocate vector mempool";
r = -ENOMEM;
goto bad;
}
/* WQ_UNBOUND greatly improves performance when running on ramdisk */
v->verify_wq = alloc_workqueue("kverityd",
WQ_HIGHPRI | WQ_MEM_RECLAIM | WQ_UNBOUND,
num_online_cpus());
if (!v->verify_wq) {
ti->error = "Cannot allocate workqueue";
r = -ENOMEM;
goto bad;
}
ti->per_bio_data_size = sizeof(struct dm_verity_io) +
v->shash_descsize + v->digest_size * 2;
r = verity_fec_ctr(v);
if (r)
goto bad;
ti->per_bio_data_size = roundup(ti->per_bio_data_size,
__alignof__(struct dm_verity_io));
return 0;
bad:
verity_dtr(ti);
return r;
}
static struct target_type verity_target = {
.name = "verity",
.version = {1, 2, 0},
.module = THIS_MODULE,
.ctr = verity_ctr,
.dtr = verity_dtr,
.map = verity_map,
.status = verity_status,
.ioctl = verity_ioctl,
.merge = verity_merge,
.iterate_devices = verity_iterate_devices,
.io_hints = verity_io_hints,
};
static int __init dm_verity_init(void)
{
int r;
r = dm_register_target(&verity_target);
if (r < 0)
DMERR("register failed %d", r);
return r;
}
static void __exit dm_verity_exit(void)
{
dm_unregister_target(&verity_target);
}
module_init(dm_verity_init);
module_exit(dm_verity_exit);
MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>");
MODULE_AUTHOR("Mandeep Baines <msb@chromium.org>");
MODULE_AUTHOR("Will Drewry <wad@chromium.org>");
MODULE_DESCRIPTION(DM_NAME " target for transparent disk integrity checking");
MODULE_LICENSE("GPL");