From: "Kasatkin, Dmitry" Subject: Re: [PATCH v3 1/1] dm-integrity: integrity protection device-mapper target Date: Tue, 5 Feb 2013 19:24:12 +0200 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-crypto@vger.kernel.org, linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org, alan.cox@intel.com To: dm-devel@redhat.com, mbroz@redhat.com, mpatocka@redhat.com Return-path: In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org Hi Mikulas, I made fixes based on your comments. Can you think now about adding this target to the device-mapper tree, may be with different name, though? - Dmitry On Tue, Jan 22, 2013 at 2:37 PM, Dmitry Kasatkin wrote: > Device-mapper "integrity" target provides transparent cryptographic integrity > protection of the underlying read-write block device using hash-based message > authentication codes (HMACs). HMACs can be stored on the same or different > block device. > > dm-integrity uses an encrypted key type, stored on the kernel keyring, to > obtain a secret key for use in cryptographic operations. Encrypted keys are > never exposed in plain text to user space. The encrypted keys are encrypted > using master key, which can either be a user defined or trusted key type. > The secret key, which is usually device specific, binds integrity data to the > device. As a result data blocks and corresponding HMACs cannot simply be > copied over from other file systems. > > Signed-off-by: Dmitry Kasatkin > --- > Documentation/device-mapper/dm-integrity.txt | 137 ++++ > drivers/md/Kconfig | 13 + > drivers/md/Makefile | 1 + > drivers/md/dm-integrity.c | 991 ++++++++++++++++++++++++++ > 4 files changed, 1142 insertions(+) > create mode 100644 Documentation/device-mapper/dm-integrity.txt > create mode 100644 drivers/md/dm-integrity.c > > diff --git a/Documentation/device-mapper/dm-integrity.txt b/Documentation/device-mapper/dm-integrity.txt > new file mode 100644 > index 0000000..394242f > --- /dev/null > +++ b/Documentation/device-mapper/dm-integrity.txt > @@ -0,0 +1,137 @@ > +dm-integrity > +=============== > + > +Device-mapper "integrity" target provides transparent cryptographic integrity > +protection of the underlying read-write block device using hash-based message > +authentication codes (HMACs). HMACs can be stored on the same or different > +block device. > + > +dm-integrity uses an encrypted key type, stored on the kernel keyring, to > +obtain a secret key for use in cryptographic operations. Encrypted keys are > +never exposed in plain text to user space. The encrypted keys are encrypted > +using master key, which can either be a user defined or trusted key type. > +The secret key, which is usually device specific, binds integrity data to the > +device. As a result data blocks and corresponding HMACs cannot simply be > +copied over from other file systems. > + > +Parameters: > + \ > +[] > + > + > + This is the device that is going to be used to store the data. > + You can specify it as a path like /dev/xxx or a device : > + number. > + > + > + Device block size. > + > + > + Starting sector within the device where data begins. > + > + > + This is the device that is going to be used to store integrity data. > + You can specify it as a path like /dev/xxx or a device : > + number. > + > + > + HMAC device block size. > + > + > + Starting sector within the device where integrity data begins. > + > + > + Hash algorithm (sha1, sha256, etc). > + > + > + HMAC algorithm, e.g. hmac(sha1), hmac(sha256), etc. > + > + > + Description is a name of a key in the kernel keyring. > + > + > + fix=1|0 - enable fix mode > + In fix mode, incorrect hmacs are replaced with correct ones. > + It is used for device initialization and debugging. > + > + stats=1|0 - turns on collecting additional statistical information. > + It is used to find out resource usage to tune memory pool > + and queue sizes for particular use case. > + > + verbose=1|0 - prints block number, collected hmac and stored hmac. > + It is used for addition debug output. > + > + > +Determine the size of integrity/hmac device > +=============== > + > +Every block device has corresponding hmac. > +While NIST does recommend to use sha256 hash algorithm instead of SHA1, > +this does not apply to hmac(sha1), because of keying. It is safe to use > +hmac(sha1), because it takes much less space and it is faster to calculate. > +hmac(sha1) size is 20 bytes. So every 4k block on the integrity device can > +store 204 hmacs. In order to get the required size of the integrity device, > +it is necessary to divide data device size by 204. See examples bellow how > +to do it from script. > + > +Example scripts > +=============== > + > +1. Setting up integrity target using data and hmac store on the same block device. > + > +[[ > +#!/bin/sh > + > +bdev=$1 > + > +# block device size > +dsize=`blockdev --getsize $bdev` > +# block size > +bs=4096 > +# sector to block shift > +sbs=3 > +# integrity record size (hmac size) > +hmac=20 > +# hmacs per block > +hpb=$((bs/hmac)) > +# target device size > +size=$((((dsize>>sbs)*hpb/(hpb+1))< + > +# load the key - in this example we just use test key > +keyctl add user kmk "testing123" @u > +keyctl add encrypted dm-int-key "load `cat /etc/keys/dm-int-key`" @u > + > +# creating the target > +table="0 $size integrity $bdev 4096 0 $bdev 4096 $size sha1 hmac(sha1) dm-int-key" > +dmsetup create dm-int --table "$table" > + > +# mounting > +mount /dev/mapper/dm-int /mnt > + > +]] > + > +2. Setting up integrity target using data and hmac store on different block devices. > + > +[[ > +#!/bin/sh > + > +bdev=$1 > +hdev=$2 > + > +# get size of the block device > +dsize=`blockdev --getsz $bdev` > +# round down the size to 4k blocks > +dsize=$((dsize & ~7)) > + > +# load the key - in this example we just use test key > +keyctl add user kmk "testing123" @u > +keyctl add encrypted dm-int-key "load `cat /etc/keys/dm-int-key`" @u > + > +# creating the target > +table="0 $dsize integrity $bdev 4096 0 $hdev 4096 0 sha1 hmac(sha1) dm-int-key" > +dmsetup create dm-int --table "$table" > + > +# mounting > +mount /dev/mapper/dm-int /mnt > + > +]] > diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig > index 91a02ee..42249c1 100644 > --- a/drivers/md/Kconfig > +++ b/drivers/md/Kconfig > @@ -388,6 +388,19 @@ config DM_VERITY > To compile this code as a module, choose M here: the module will > be called dm-verity. > > +config DM_INTEGRITY > + tristate "Integrity target support" > + depends on BLK_DEV_DM > + select CRYPTO > + select CRYPTO_HMAC > + select DM_BUFIO > + select KEYS > + ---help--- > + If you say Y here, then your ... > + > + To compile this as a module, choose M here: the module > + will be called dm-integrity. > + > If unsure, say N. > > endif # MD > diff --git a/drivers/md/Makefile b/drivers/md/Makefile > index 94dce8b..49b212f 100644 > --- a/drivers/md/Makefile > +++ b/drivers/md/Makefile > @@ -41,6 +41,7 @@ obj-$(CONFIG_DM_PERSISTENT_DATA) += persistent-data/ > obj-$(CONFIG_DM_MIRROR) += dm-mirror.o dm-log.o dm-region-hash.o > obj-$(CONFIG_DM_LOG_USERSPACE) += dm-log-userspace.o > obj-$(CONFIG_DM_ZERO) += dm-zero.o > +obj-$(CONFIG_DM_INTEGRITY) += dm-integrity.o > obj-$(CONFIG_DM_RAID) += dm-raid.o > obj-$(CONFIG_DM_THIN_PROVISIONING) += dm-thin-pool.o > obj-$(CONFIG_DM_VERITY) += dm-verity.o > diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c > new file mode 100644 > index 0000000..5cc33c3 > --- /dev/null > +++ b/drivers/md/dm-integrity.c > @@ -0,0 +1,991 @@ > +/* > + * dm-integrity - device mapper integrity target > + * > + * Copyright (C) 2012,2013 Intel Corporation. > + * > + * Author: Dmitry Kasatkin > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms and conditions of the GNU General Public License, > + * version 2, as published by the Free Software Foundation. > + * > + * This program is distributed in the hope it will be useful, but WITHOUT > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for > + * more details. > + * > + * You should have received a copy of the GNU General Public License along with > + * this program; if not, write to the Free Software Foundation, Inc., > + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. > + * > + */ > + > +#define DM_MSG_PREFIX KBUILD_MODNAME > + > +#define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__ > + > +#include "dm.h" > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include "dm-bufio.h" > + > +#define DM_INT_STATS > + > +#define DM_INT_MIN_IOS 16 > +#define DM_INT_BLOCK_SIZE PAGE_SIZE > +#define DM_INT_MAX_KEY_SIZE 128 > + > +/* best parameters for fastest Ubuntu boot */ > +#define DM_INT_PREFETCH_COUNT 16 > + > +struct ahash_result { > + struct completion completion; > + int err; > +}; > + > +struct dm_int_io { > + struct dm_int *dmi; /* mapping it belongs to */ > + struct work_struct work; > + > +#define DM_INT_BIO_DONE 1 > +#define DM_INT_VERIFIED 2 > + unsigned long flags; > + > + atomic_t count; > + int error; > + > + sector_t sector; > + > + bio_end_io_t *bi_end_io; /* original bio callback */ > + void *bi_private; /* original bio private data */ > + unsigned int bi_size; > + > + struct ahash_request req; > +}; > + > +/* > + * integrity mapping configuration > + */ > +struct dm_int { > + struct dm_target *ti; > + struct dm_dev *dev; > + char *table_string; > + sector_t start; > + struct dm_dev *hdev; > + sector_t hmac_start; > + sector_t hmac_count; > + > + struct workqueue_struct *io_queue; > + > + struct crypto_ahash *ahash; > + struct crypto_shash *hmac; > + > + struct notifier_block reboot_nb; > + > + struct dm_bufio_client *bufio; > + > + unsigned int hmac_size; > + unsigned int data_block_size; > + unsigned int data_block_bits; > + unsigned int hmac_block_size; > + unsigned int hmac_block_bits; > + unsigned int hmac_per_block; > + unsigned int hmac_block_shift; > + > +#define DM_INT_FLAGS_FIX 0x01 /* fix wrong hmacs */ > +#define DM_INT_FLAGS_VERBOSE 0x02 /* show failed blocks */ > +#define DM_INT_FLAGS_ZERO 0x04 /* zero on error */ > +#define DM_INT_FLAGS_SYNC_MODE 0x08 /* sync mode */ > + > + unsigned int flags; > + > + atomic_t violations; > + > +#ifdef DM_INT_STATS > +#define DM_INT_FLAGS_STATS 0x80 /* calc statistics */ > + atomic_t io_count; > + int io_count_max; > + atomic_t data_write_count; > + atomic_t data_read_count; > +#else > +/* setting to 0 will eliminate the code due to optimization */ > +#define DM_INT_FLAGS_STATS 0x00 > +#endif > +}; > + > + > +#define io_block(io) (io->sector >> (io->dmi->data_block_bits - SECTOR_SHIFT)) > + > +static void dm_int_queue_hmac(struct dm_int_io *io); > + > +/* > + * Get the key from the TPM for the HMAC > + */ > +static int dm_int_init_crypto(struct dm_int *dmi, const char *hash_algo, > + const char *hmac_algo, const char *keyname) > +{ > + struct key *key; > + struct encrypted_key_payload *ekp; > + int err = -EINVAL; > + > + dmi->ahash = crypto_alloc_ahash(hash_algo, 0, 0); > + if (IS_ERR(dmi->ahash)) { > + err = PTR_ERR(xchg(&dmi->ahash, NULL)); > + DMERR("failed to load %s algorithm: %d", hash_algo, err); > + dmi->ti->error = "Cannot allocate hash algorithm"; > + return err; > + } > + > + dmi->hmac = crypto_alloc_shash(hmac_algo, 0, 0); > + if (IS_ERR(dmi->hmac)) { > + err = PTR_ERR(xchg(&dmi->hmac, NULL)); > + DMERR("failed to load %s algorithm: %d", hmac_algo, err); > + dmi->ti->error = "Cannot allocate hash algorithm"; > + return err; > + } > + > + key = request_key(&key_type_encrypted, keyname, NULL); > + if (IS_ERR(key)) { > + dmi->ti->error = "Invalid key name"; > + return -ENOENT; > + } > + > + down_read(&key->sem); > + ekp = key->payload.data; > + if (ekp->decrypted_datalen <= DM_INT_MAX_KEY_SIZE) > + err = crypto_shash_setkey(dmi->hmac, ekp->decrypted_data, > + ekp->decrypted_datalen); > + > + /* burn the original key contents */ > + /*memset(ekp->decrypted_data, 0, ekp->decrypted_datalen); */ > + up_read(&key->sem); > + key_put(key); > + > + return err; > +} > + > +static void dm_int_io_get(struct dm_int_io *io) > +{ > + atomic_inc(&io->count); > + > + pr_debug("block: %llu, pending %d\n", > + (loff_t)io_block(io), atomic_read(&io->count)); > +} > + > +static void dm_int_io_put(struct dm_int_io *io) > +{ > + struct dm_int *dmi = io->dmi; > + struct bio *bio; > + int err = io->error; > + > + pr_debug("block: %llu, pending %d\n", > + (loff_t)io_block(io), atomic_read(&io->count)); > + > + if (!atomic_dec_and_test(&io->count)) > + return; > + > + /* request has completed */ > + if (!err && test_bit(DM_INT_BIO_DONE, &io->flags) && > + !test_bit(DM_INT_VERIFIED, &io->flags)) { > + /* io->count will be 1 */ > + pr_debug("queue to verify block: %llu\n", (loff_t)io_block(io)); > + dm_int_queue_hmac(io); > + return; > + } > + > + pr_debug("io done: err: %d, pending: %d\n", > + err, atomic_read(&io->count)); > + > + bio = dm_bio_from_per_bio_data(io, dmi->ti->per_bio_data_size); > + > + if (dmi->flags & DM_INT_FLAGS_STATS) > + atomic_dec(&dmi->io_count); > + > + if (err) > + DMERR_LIMIT("%s block %llu failed (%d) - %s", > + bio_data_dir(bio) ? "write" : "read", > + (loff_t)io_block(io), err, > + err == -EKEYREJECTED ? > + "hmac mismatch" : " system error"); > + > + bio_endio(bio, err); /* finally completed, end main bio */ > +} > + > +static void dm_int_prefetch(struct dm_int_io *io) > +{ > + struct dm_int *dmi = io->dmi; > + sector_t first, last, data; > + loff_t offset; > + > + /* block number to read */ > + offset = io->sector << SECTOR_SHIFT; > + data = offset >> dmi->data_block_bits; > + if (dmi->hmac_block_shift) > + first = data >> dmi->hmac_block_shift; > + else { > + first = data; > + sector_div(first, dmi->hmac_per_block); > + } > + > + /* offset to the last byte of data */ > + offset += (io->bi_size - 1); > + data = offset >> dmi->data_block_bits; > + if (dmi->hmac_block_shift) > + last = data >> dmi->hmac_block_shift; > + else { > + last = data; > + sector_div(last, dmi->hmac_per_block); > + } > + > + /* prefetch multiple of DM_INT_PREFETCH_COUNT */ > + first = round_down(first, DM_INT_PREFETCH_COUNT); > + last = round_up(last + 1, DM_INT_PREFETCH_COUNT); > + /* check the end of the device */ > + if (last > dmi->hmac_count) > + last = dmi->hmac_count; > + > + dm_bufio_prefetch(dmi->bufio, dmi->hmac_start + first, last - first); > +} > + > +static int dm_int_verify_hmac(struct dm_int_io *io, loff_t offset, > + u8 *collected, int update) > +{ > + struct dm_int *dmi = io->dmi; > + sector_t block, data = offset >> dmi->data_block_bits; > + unsigned int index; > + u8 *digest; > + int err = 0; > + struct dm_buffer *buf; > + > + if (dmi->hmac_block_shift) { > + block = data >> dmi->hmac_block_shift; > + index = data & ((1 << dmi->hmac_block_shift) - 1); > + } else { > + block = data; > + index = sector_div(block, dmi->hmac_per_block); > + } > + > + pr_debug("hmac: block: %llu, index: %u\n", block, index); > + > + digest = dm_bufio_read(dmi->bufio, dmi->hmac_start + block, &buf); > + if (unlikely(IS_ERR(digest))) > + return PTR_ERR(digest); > + > + digest += dmi->hmac_size * index; > + > + if (!update) { > + err = memcmp(digest, collected, dmi->hmac_size); > + if (err) { > + err = -EKEYREJECTED; > + /* update buffer and store it back */ > + atomic_inc(&dmi->violations); > + if (dmi->flags & DM_INT_FLAGS_FIX) { > + err = 0; > + update = 1; > + } > + if (dmi->flags & DM_INT_FLAGS_VERBOSE) { > + DMERR("hmac mismatch: block: %llu, index: %u", > + block, index); > + print_hex_dump(KERN_CRIT, "collected: ", > + 0, 32, 1, collected, 20, 0); > + print_hex_dump(KERN_CRIT, "hmac: ", > + 0, 32, 1, digest, 20, 0); > + } > + } > + } > + > + if (update) { > + memcpy(digest, collected, dmi->hmac_size); > + dm_bufio_mark_buffer_dirty(buf); > + } > + > + dm_bufio_release(buf); > + > + return err; > +} > + > +static void dm_int_ahash_complete(struct crypto_async_request *req, int err) > +{ > + struct ahash_result *res = req->data; > + > + if (err == -EINPROGRESS) > + return; > + res->err = err; > + complete(&res->completion); > +} > + > +static int dm_int_ahash_wait(int err, struct ahash_result *res) > +{ > + switch (err) { > + case 0: > + break; > + case -EINPROGRESS: > + case -EBUSY: > + wait_for_completion(&res->completion); > + err = res->err; > + if (!res->err) { > + INIT_COMPLETION(res->completion); > + break; > + } > + /* fall through */ > + default: > + DMERR("HMAC calculation failed: err: %d", err); > + } > + > + return err; > +} > + > +static int dm_int_calc_hmac(struct dm_int_io *io, loff_t offset, > + u8 *digest, unsigned int size, u8 *hmac) > +{ > + struct dm_int *dmi = io->dmi; > + int err; > + struct { > + struct shash_desc shash; > + char ctx[crypto_shash_descsize(dmi->hmac)]; > + } desc; > + > + desc.shash.tfm = dmi->hmac; > + desc.shash.flags = CRYPTO_TFM_REQ_MAY_SLEEP; > + > + err = crypto_shash_init(&desc.shash); > + if (!err) > + err = crypto_shash_update(&desc.shash, digest, size); > + if (!err) > + err = crypto_shash_finup(&desc.shash, (u8 *)&offset, > + sizeof(offset), hmac); > + if (err) > + DMERR_LIMIT("calc hmac failed: %d", err); > + return err; > +} > + > +static void dm_int_verify_io(struct dm_int_io *io) > +{ > + struct dm_int *dmi = io->dmi; > + struct bio *bio; > + struct bio_vec *bv; > + int i, err = -EIO; > + struct scatterlist sg[1]; > + u8 hmac[dmi->hmac_size]; > + u8 digest[crypto_ahash_digestsize(dmi->ahash)]; > + loff_t offset = io->sector << SECTOR_SHIFT; > + struct ahash_request *req = &io->req; > + struct ahash_result res; > + ssize_t size = io->bi_size; > + > + init_completion(&res.completion); > + ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | > + CRYPTO_TFM_REQ_MAY_SLEEP, > + dm_int_ahash_complete, &res); > + > + sg_init_table(sg, 1); > + > + bio = dm_bio_from_per_bio_data(io, dmi->ti->per_bio_data_size); > + > + pr_debug("block: %llu, size: %d, vcnt: %d, idx: %d\n", > + (loff_t)io_block(io), bio->bi_size, bio->bi_vcnt, bio->bi_idx); > + > + bio_for_each_segment(bv, bio, i) { > + pr_debug("bv: %d: offset: %llu, bv_offset: %d, bv_len: %d\n", > + i, offset, bv->bv_offset, bv->bv_len); > + > + BUG_ON(bv->bv_offset & (dmi->data_block_size - 1)); > + BUG_ON(bv->bv_len & (dmi->data_block_size - 1)); > + > + sg_set_page(sg, bv->bv_page, bv->bv_len, bv->bv_offset); > + > + ahash_request_set_crypt(req, sg, digest, bv->bv_len); > + > + err = crypto_ahash_digest(req); > + err = dm_int_ahash_wait(err, req->base.data); > + if (err) > + break; > + > + err = dm_int_calc_hmac(io, offset, digest, sizeof(digest), > + hmac); > + if (err) > + break; > + > + err = dm_int_verify_hmac(io, offset, hmac, bio_data_dir(bio)); > + if (err) { > + if (dmi->flags & DM_INT_FLAGS_ZERO) { > + void *ptr = kmap(bv->bv_page); > + if (!ptr) > + break; > + DMERR_LIMIT("Ignoring bad HMAC"); > + memset(ptr + bv->bv_offset, 0, bv->bv_len); > + kunmap(ptr); > + err = 0; > + } else > + break; > + } > + > + offset += bv->bv_len; > + size -= bv->bv_len; > + } > + > + WARN(!err && size, "bio has date left: %zd\n", size); > + > + io->error = err; > + set_bit(DM_INT_VERIFIED, &io->flags); > + > + if (dmi->flags & DM_INT_FLAGS_SYNC_MODE) > + dm_bufio_write_dirty_buffers(dmi->bufio); > +} > + > +static void dm_int_hmac_task(struct work_struct *work) > +{ > + struct dm_int_io *io = container_of(work, struct dm_int_io, work); > + > + dm_int_verify_io(io); > + dm_int_io_put(io); > +} > + > +static void dm_int_queue_hmac(struct dm_int_io *io) > +{ > + struct dm_int *dmi = io->dmi; > + int err; > + > + /* what if it is queued already? */ > + dm_int_io_get(io); > + err = queue_work(dmi->io_queue, &io->work); > + if (!err) > + dm_int_io_put(io); > + BUG_ON(!err); > +} > + > +static void dm_int_end_io(struct bio *bio, int err) > +{ > + struct dm_int_io *io = bio->bi_private; > + > + pr_debug("pending: %d, block: %llu, size: %u, vcnt: %d, idx: %d\n", > + atomic_read(&io->count), (loff_t)io_block(io), > + bio->bi_size, bio->bi_vcnt, bio->bi_idx); > + > + if (unlikely(!bio_flagged(bio, BIO_UPTODATE) && !err)) > + err = -EIO; > + > + if (err) > + DMERR("bio failed: %d", err); > + > + if (unlikely(err)) > + io->error = err; > + > + set_bit(DM_INT_BIO_DONE, &io->flags); > + > + bio->bi_private = io->bi_private; > + bio->bi_end_io = io->bi_end_io; > + > + dm_int_io_put(io); > +} > + > +static void dm_int_start_io(struct dm_int_io *io) > +{ > + struct dm_int *dmi = io->dmi; > + struct bio *bio; > + > + if (io->error) > + return; > + > + bio = dm_bio_from_per_bio_data(io, dmi->ti->per_bio_data_size); > + > + io->bi_private = bio->bi_private; > + io->bi_end_io = bio->bi_end_io; > + > + /* io->sector starts from 0 */ > + bio->bi_sector = dmi->start + io->sector; > + bio->bi_bdev = dmi->dev->bdev; > + > + bio->bi_private = io; > + bio->bi_end_io = dm_int_end_io; > + > + dm_int_io_get(io); > + > + if (dmi->flags & DM_INT_FLAGS_STATS) { > + if (bio_data_dir(bio) == READ) > + atomic_inc(&dmi->data_read_count); > + else > + atomic_inc(&dmi->data_write_count); > + } > + > + generic_make_request(bio); > +} > + > +static struct dm_int_io *dm_int_io_alloc(struct dm_int *dmi, > + struct bio *bio, sector_t sector) > +{ > + struct dm_int_io *io; > + > + /* no allocation */ > + io = dm_per_bio_data(bio, dmi->ti->per_bio_data_size); > + > + io->dmi = dmi; > + io->bi_size = bio->bi_size; > + io->sector = sector; > + io->error = 0; > + io->flags = 0; > + > + INIT_WORK(&io->work, dm_int_hmac_task); > + > + ahash_request_set_tfm(&io->req, dmi->ahash); > + > + atomic_set(&io->count, 1); > + > + /* stats */ > + if (dmi->flags & DM_INT_FLAGS_STATS) { > + atomic_inc(&dmi->io_count); > + if (atomic_read(&dmi->io_count) > dmi->io_count_max) > + dmi->io_count_max = atomic_read(&dmi->io_count); > + } > + > + return io; > +} > + > +static int dm_int_map(struct dm_target *ti, struct bio *bio) > +{ > + struct dm_int *dmi = ti->private; > + struct dm_int_io *io; > + > + /* > + * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues. > + * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight > + * - for REQ_DISCARD caller must use flush if IO ordering matters > + */ > + if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) { > + bio->bi_bdev = dmi->dev->bdev; > + bio->bi_sector = > + dmi->start + dm_target_offset(ti, bio->bi_sector); > + return DM_MAPIO_REMAPPED; > + } > + > + /* a check to see if something unhandled might come */ > + if (!bio->bi_size || !bio->bi_vcnt) > + DMERR("bio without data: size: %d, vcnt: %d", > + bio->bi_size, bio->bi_vcnt); > + > + BUG_ON(bio->bi_sector & (to_sector(dmi->data_block_size) - 1)); > + BUG_ON(bio->bi_size & (dmi->data_block_size - 1)); > + > + io = dm_int_io_alloc(dmi, bio, dm_target_offset(ti, bio->bi_sector)); > + > + pr_debug("%s block: %llu, size: %u, vcnt: %d, idx: %d, %s (%d)\n", > + bio_data_dir(bio) ? "write" : "read", (loff_t)io_block(io), > + bio->bi_size, bio->bi_vcnt, bio->bi_idx, > + current->comm, current->pid); > + > + dm_int_start_io(io); > + dm_int_prefetch(io); > + > + dm_int_io_put(io); > + > + return DM_MAPIO_SUBMITTED; > +} > + > +static void dm_int_cleanup(struct dm_target *ti) > +{ > + struct dm_int *dmi = (struct dm_int *)ti->private; > + > + if (dmi->bufio) > + dm_bufio_client_destroy(dmi->bufio); > + if (dmi->io_queue) > + destroy_workqueue(dmi->io_queue); > + if (dmi->ahash) > + crypto_free_ahash(dmi->ahash); > + if (dmi->hmac) > + crypto_free_shash(dmi->hmac); > + if (dmi->hdev) > + dm_put_device(ti, dmi->hdev); > + if (dmi->dev) > + dm_put_device(ti, dmi->dev); > + kfree(dmi->table_string); > + kfree(dmi); > +} > + > +static void dm_int_sync(struct dm_int *dmi) > +{ > + /* first flush hmac queue, which might schedule idata delayed work */ > + flush_workqueue(dmi->io_queue); > + /* write all updated hmac blocks */ > + dm_bufio_write_dirty_buffers(dmi->bufio); > +} > + > +static int dm_int_notify_reboot(struct notifier_block *this, > + unsigned long code, void *x) > +{ > + struct dm_int *dmi = container_of(this, struct dm_int, reboot_nb); > + > + if ((code == SYS_DOWN) || (code == SYS_HALT) || > + (code == SYS_POWER_OFF)) { > + dmi->flags |= DM_INT_FLAGS_SYNC_MODE; > + pr_info("syncing target..."); > + dm_int_sync(dmi); > + pr_cont(" done.\n"); > + } > + return NOTIFY_DONE; > +} > + > +/* > + * Construct an integrity mapping: > + * \ > + * [opt_params] > + */ > +static int dm_int_ctr(struct dm_target *ti, unsigned int argc, char **argv) > +{ > + struct dm_int *dmi; > + int err, i, count; > + unsigned long long tmpll; > + char table[256], dummy; > + unsigned tmp; > + fmode_t mode; > + sector_t datadevsize, hmacdevsize, maxdatasize, maxhmacsize; > + > + if (argc < 9) { > + ti->error = "Invalid argument count"; > + return -EINVAL; > + } > + > + dmi = kzalloc(sizeof(*dmi), GFP_KERNEL); > + if (dmi == NULL) { > + ti->error = "dm-integrity: Cannot allocate linear context"; > + return -ENOMEM; > + } > + > + dmi->ti = ti; > + ti->private = dmi; > + > + err = -EINVAL; > + > + mode = dm_table_get_mode(ti->table); > + > + if (dm_get_device(ti, argv[0], mode, &dmi->dev)) { > + ti->error = "Device lookup failed"; > + goto err; > + } > + > + if (sscanf(argv[1], "%u%c", &tmp, &dummy) != 1 || > + !is_power_of_2(tmp) || > + tmp < bdev_logical_block_size(dmi->dev->bdev) || > + tmp > PAGE_SIZE) { > + ti->error = "Invalid device block size"; > + goto err; > + } > + dmi->data_block_size = tmp; > + dmi->data_block_bits = ffs(dmi->data_block_size) - 1; > + > + if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) { > + ti->error = "Invalid device start"; > + goto err; > + } > + dmi->start = tmpll; > + > + if (dm_get_device(ti, argv[3], mode, &dmi->hdev)) { > + ti->error = "HMAC device lookup failed"; > + goto err; > + } > + > + if (sscanf(argv[4], "%u%c", &tmp, &dummy) != 1 || > + !is_power_of_2(tmp) || > + tmp < bdev_logical_block_size(dmi->dev->bdev) || > + tmp > PAGE_SIZE) { > + ti->error = "Invalid device block size"; > + goto err; > + } > + dmi->hmac_block_size = tmp; > + dmi->hmac_block_bits = ffs(dmi->hmac_block_size) - 1; > + > + if (sscanf(argv[5], "%llu%c", &tmpll, &dummy) != 1) { > + ti->error = "Invalid hmac device start"; > + goto err; > + } > + dmi->hmac_start = tmpll; > + > + err = dm_int_init_crypto(dmi, argv[6], argv[7], argv[8]); > + if (err) > + goto err; > + > + count = snprintf(table, sizeof(table), "%s %u %llu %s %u %llu %s %s %s", > + dmi->dev->name, dmi->data_block_size, dmi->start, > + dmi->hdev->name, dmi->hmac_block_size, dmi->hmac_start, > + argv[6], argv[7], argv[8]); > + > + for (i = 9; i < argc; i++) { > + count += snprintf(table + count, sizeof(table) - count, > + " %s", argv[i]); > + } > + > + dmi->table_string = kstrdup(table, GFP_KERNEL); > + > + dmi->hmac_size = crypto_shash_digestsize(dmi->hmac); > + > + /* how many hmacs do we need for data device */ > + dmi->hmac_count = ti->len >> (dmi->data_block_bits - SECTOR_SHIFT); > + > + datadevsize = i_size_read(dmi->dev->bdev->bd_inode) >> SECTOR_SHIFT; > + hmacdevsize = i_size_read(dmi->hdev->bdev->bd_inode) >> SECTOR_SHIFT; > + > + err = -EINVAL; > + > + if (dmi->start > datadevsize) { > + DMERR("start sector is beyond device size: %llu (%llu)", > + dmi->start, datadevsize); > + ti->error = "start sector is beyond data device size"; > + goto err; > + } > + > + if (dmi->hmac_start > hmacdevsize) { > + DMERR("start sector is beyond device size: %llu (%llu)", > + dmi->hmac_start, hmacdevsize); > + ti->error = "start sector is beyond integrity device size"; > + goto err; > + } > + > + if (dmi->dev->bdev == dmi->hdev->bdev) { > + if (dmi->hmac_start > dmi->start) { > + maxdatasize = dmi->hmac_start - dmi->start; > + maxhmacsize = datadevsize - dmi->hmac_start; > + } else { > + maxhmacsize = dmi->start - dmi->hmac_start; > + maxdatasize = datadevsize - dmi->start; > + } > + } else { > + maxdatasize = datadevsize - dmi->start; > + maxhmacsize = hmacdevsize - dmi->hmac_start; > + } > + > + if (ti->len > maxdatasize) { > + DMERR("target size is too big: %llu (%llu)", > + (loff_t)ti->len, maxdatasize); > + ti->error = "target size is too big"; > + goto err; > + } > + > + /* hmac start in blocks */ > + dmi->hmac_start >>= (dmi->hmac_block_bits - SECTOR_SHIFT); > + > + /* optimize for SHA256 which is 32 bytes */ > + if (is_power_of_2(dmi->hmac_size)) { > + dmi->hmac_block_shift = > + dmi->hmac_block_bits - (ffs(dmi->hmac_size) - 1); > + /* how many hmac blocks do we need */ > + dmi->hmac_count >>= dmi->hmac_block_shift; > + } else { > + dmi->hmac_per_block = dmi->hmac_block_size / dmi->hmac_size; > + /* how many hmac blocks do we need */ > + tmpll = sector_div(dmi->hmac_count, dmi->hmac_per_block); > + if (tmpll) > + dmi->hmac_count++; > + } > + > + /* device may hold as many hmac blocks */ > + maxhmacsize >>= (dmi->hmac_block_bits - SECTOR_SHIFT); > + > + if (dmi->hmac_count > maxhmacsize) { > + DMERR("HMAC device is too small: %llu (%llu)", > + dmi->hmac_count, maxhmacsize); > + ti->error = "HMAC device is too small"; > + goto err; > + } > + > + ti->num_discard_requests = 1; > + > + for (i = 9; i < argc; i++) { > + if (!strcmp(argv[i], "fix")) > + dmi->flags |= DM_INT_FLAGS_FIX; > + else if (!strcmp(argv[i], "zero_on_error")) > + dmi->flags |= DM_INT_FLAGS_ZERO; > + else if (!strcmp(argv[i], "stats")) > + dmi->flags |= DM_INT_FLAGS_STATS; > + else if (!strcmp(argv[i], "verbose")) > + dmi->flags |= DM_INT_FLAGS_VERBOSE; > + else if (!strcmp(argv[i], "disallow_discards")) > + ti->num_discard_requests = 0; > + } > + > + ti->per_bio_data_size = sizeof(struct dm_int_io); > + ti->per_bio_data_size += crypto_ahash_reqsize(dmi->ahash); > + > + err = -ENOMEM; > + > + dmi->io_queue = alloc_workqueue("dm_int_hmac", > + WQ_CPU_INTENSIVE | > + WQ_HIGHPRI | > + WQ_UNBOUND | > + WQ_MEM_RECLAIM, > + 1); > + if (!dmi->io_queue) { > + ti->error = "Couldn't create dm_int hmac queue"; > + goto err; > + } > + > + dmi->bufio = dm_bufio_client_create(dmi->hdev->bdev, > + dmi->hmac_block_size, 1, 0, > + NULL, NULL); > + if (IS_ERR(dmi->bufio)) { > + ti->error = "Cannot initialize dm-bufio"; > + err = PTR_ERR(xchg(&dmi->bufio, NULL)); > + goto err; > + } > + > + ti->num_flush_requests = 1; > + /* it should depend on read block device... */ > + /*ti->discard_zeroes_data_unsupported = true;*/ > + > + dmi->reboot_nb.notifier_call = dm_int_notify_reboot, > + dmi->reboot_nb.priority = INT_MAX, /* before any real devices */ > + /* always returns 0 */ > + register_reboot_notifier(&dmi->reboot_nb); > + > + return 0; > + > +err: > + dm_int_cleanup(ti); > + return err; > +} > + > +static void dm_int_dtr(struct dm_target *ti) > +{ > + struct dm_int *dmi = (struct dm_int *)ti->private; > + > + unregister_reboot_notifier(&dmi->reboot_nb); > + > + dm_int_cleanup(ti); > +} > + > +static int dm_int_ioctl(struct dm_target *ti, unsigned int cmd, > + unsigned long arg) > +{ > + struct dm_int *dmi = (struct dm_int *)ti->private; > + struct dm_dev *dev = dmi->dev; > + int err = 0; > + > + if (cmd == BLKFLSBUF) > + dm_int_sync(dmi); > + > + /* > + * Only pass ioctls through if the device sizes match exactly. > + */ > + if (dmi->start || > + ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT) > + err = scsi_verify_blk_ioctl(NULL, cmd); > + > + return err ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg); > +} > + > +static int dm_int_merge(struct dm_target *ti, struct bvec_merge_data *bvm, > + struct bio_vec *biovec, int max_size) > +{ > + struct dm_int *dmi = ti->private; > + struct request_queue *q = bdev_get_queue(dmi->dev->bdev); > + > + if (!q->merge_bvec_fn) > + return max_size; > + > + bvm->bi_bdev = dmi->dev->bdev; > + bvm->bi_sector = dmi->start + dm_target_offset(ti, bvm->bi_sector); > + > + return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); > +} > + > +static int dm_int_iterate_devices(struct dm_target *ti, > + iterate_devices_callout_fn fn, void *data) > +{ > + struct dm_int *dmi = ti->private; > + > + return fn(ti, dmi->dev, dmi->start, ti->len, data); > +} > + > +static void dm_int_io_hints(struct dm_target *ti, struct queue_limits *limits) > +{ > + struct dm_int *dmi = ti->private; > + > + limits->logical_block_size = dmi->data_block_size; > + limits->physical_block_size = dmi->data_block_size; > + blk_limits_io_min(limits, dmi->data_block_size); > +} > + > +static void dm_int_postsuspend(struct dm_target *ti) > +{ > + struct dm_int *dmi = ti->private; > + > + dm_int_sync(dmi); > + > + DMINFO("%s suspended\n", dm_device_name(dm_table_get_md(ti->table))); > +} > + > +static int dm_int_status(struct dm_target *ti, status_type_t type, > + unsigned status_flags, char *result, unsigned maxlen) > +{ > + struct dm_int *dmi = (struct dm_int *)ti->private; > + unsigned int sz = 0; > + > + switch (type) { > + case STATUSTYPE_INFO: > +#ifdef DM_INT_STATS > + DMEMIT("io: %d (%d), read: %d, write: %d, violations: %d", > + atomic_read(&dmi->io_count), dmi->io_count_max, > + atomic_read(&dmi->data_read_count), > + atomic_read(&dmi->data_write_count), > + atomic_read(&dmi->violations)); > +#else > + DMEMIT("violations: %d", > + atomic_read(&dmi->violations)); > +#endif > + break; > + > + case STATUSTYPE_TABLE: > + DMEMIT("%s", dmi->table_string); > + break; > + } > + return 0; > +} > + > +static struct target_type dm_int_target = { > + .name = "integrity", > + .version = {0, 1, 0}, > + .module = THIS_MODULE, > + .ctr = dm_int_ctr, > + .dtr = dm_int_dtr, > + .map = dm_int_map, > + .status = dm_int_status, > + .ioctl = dm_int_ioctl, > + .postsuspend = dm_int_postsuspend, > + .merge = dm_int_merge, > + .iterate_devices = dm_int_iterate_devices, > + .io_hints = dm_int_io_hints, > +}; > + > +int __init dm_int_init(void) > +{ > + int err; > + > + err = dm_register_target(&dm_int_target); > + if (err < 0) > + DMERR("register failed %d", err); > + > + return err; > +} > + > +void dm_int_exit(void) > +{ > + dm_unregister_target(&dm_int_target); > +} > + > +/* Module hooks */ > +module_init(dm_int_init); > +module_exit(dm_int_exit); > + > +MODULE_DESCRIPTION(DM_NAME " integrity target"); > +MODULE_AUTHOR("Dmitry Kasatkin"); > +MODULE_LICENSE("GPL"); > -- > 1.7.10.4 >