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 <dmitry.kasatkin@xxxxxxxxx>
---
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:
+<dev> <bs> <start> <hdev> <hbs> <hstart> <hash_algo> <hmac_algo> <key_desc> \
+[<opt_params>]
+
+<dev>
+ 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 <major>:<minor>
+ number.
+
+<bs>
+ Device block size.
+
+<start>
+ Starting sector within the device where data begins.
+
+<hdev>
+ 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 <major>:<minor>
+ number.
+
+<hbs>
+ HMAC device block size.
+
+<hstart>
+ Starting sector within the device where integrity data begins.
+
+<hash_algo>
+ Hash algorithm (sha1, sha256, etc).
+
+<hmac_algo>
+ HMAC algorithm, e.g. hmac(sha1), hmac(sha256), etc.
+
+<key_desc>
+ Description is a name of a key in the kernel keyring.
+
+<opt_params>
+ 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))<<sbs))
+
+# 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 <dmitry.kasatkin@xxxxxxxxx>
+ *
+ * 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 <linux/module.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/slab.h>
+#include <linux/device-mapper.h>
+#include <linux/crypto.h>
+#include <linux/scatterlist.h>
+#include <crypto/sha.h>
+#include <crypto/hash.h>
+#include <keys/encrypted-type.h>
+#include <linux/wait.h>
+#include <linux/reboot.h>
+
+#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:
+ * <dev> <bs> <start> <hdev> <hbs> <hstart> <hash_algo> <hmac_algo> <keyname> \
+ * [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
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