blob: b86923f2df24715283e86afbe46d50a2a50dd05f [file] [log] [blame]
/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that 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.
*/
#include <linux/completion.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/mempool.h>
#include <linux/slab.h>
#include <linux/crypto.h>
#include <linux/workqueue.h>
#include <linux/backing-dev.h>
#include <linux/atomic.h>
#include <linux/scatterlist.h>
#include <crypto/scatterwalk.h>
#include <asm/page.h>
#include <asm/unaligned.h>
#include <crypto/hash.h>
#include <crypto/md5.h>
#include <crypto/algapi.h>
#include <mach/qcrypto.h>
#include <linux/device-mapper.h>
#define DM_MSG_PREFIX "req-crypt"
#define MAX_SG_LIST 1024
#define REQ_DM_512_KB (512*1024)
#define MAX_ENCRYPTION_BUFFERS 1
#define MIN_IOS 16
#define MIN_POOL_PAGES 32
#define KEY_SIZE_XTS 32
#define AES_XTS_IV_LEN 16
#define DM_REQ_CRYPT_ERROR -1
#define DM_REQ_CRYPT_ERROR_AFTER_PAGE_MALLOC -2
#define FDE_CRYPTO_DEVICE 0
struct req_crypt_result {
struct completion completion;
int err;
};
struct dm_dev *dev;
static struct kmem_cache *_req_crypt_io_pool;
sector_t start_sector_orig;
struct workqueue_struct *req_crypt_queue;
mempool_t *req_io_pool;
mempool_t *req_page_pool;
struct crypto_ablkcipher *tfm;
struct req_dm_crypt_io {
struct work_struct work;
struct request *cloned_request;
int error;
atomic_t pending;
struct timespec start_time;
};
static void req_crypt_cipher_complete
(struct crypto_async_request *req, int err);
static void req_crypt_inc_pending(struct req_dm_crypt_io *io)
{
atomic_inc(&io->pending);
}
static void req_crypt_dec_pending_encrypt(struct req_dm_crypt_io *io)
{
int error = 0;
struct request *clone = NULL;
if (io) {
error = io->error;
if (io->cloned_request) {
clone = io->cloned_request;
} else {
DMERR("%s io->cloned_request is NULL\n",
__func__);
/*
* If Clone is NULL we cannot do anything,
* this should never happen
*/
BUG();
}
} else {
DMERR("%s io is NULL\n", __func__);
/*
* If Clone is NULL we cannot do anything,
* this should never happen
*/
BUG();
}
atomic_dec(&io->pending);
if (error < 0) {
dm_kill_unmapped_request(clone, error);
mempool_free(io, req_io_pool);
} else
dm_dispatch_request(clone);
}
static void req_crypt_dec_pending_decrypt(struct req_dm_crypt_io *io)
{
int error = 0;
struct request *clone = NULL;
if (io) {
error = io->error;
if (io->cloned_request) {
clone = io->cloned_request;
} else {
DMERR("%s io->cloned_request is NULL\n",
__func__);
/*
* If Clone is NULL we cannot do anything,
* this should never happen
*/
BUG();
}
} else {
DMERR("%s io is NULL\n",
__func__);
/*
* If Clone is NULL we cannot do anything,
* this should never happen
*/
BUG();
}
/* Should never get here if io or Clone is NULL */
dm_end_request(clone, error);
atomic_dec(&io->pending);
mempool_free(io, req_io_pool);
}
/*
* The callback that will be called by the worker queue to perform Decryption
* for reads and use the dm function to complete the bios and requests.
*/
static void req_cryptd_crypt_read_convert(struct req_dm_crypt_io *io)
{
struct request *clone = NULL;
int error = 0;
int total_sg_len = 0, rc = 0, total_bytes_in_req = 0;
struct ablkcipher_request *req = NULL;
struct req_crypt_result result;
struct scatterlist *req_sg_read = NULL;
int err = 0;
u8 IV[AES_XTS_IV_LEN];
if (io) {
error = io->error;
if (io->cloned_request) {
clone = io->cloned_request;
} else {
DMERR("%s io->cloned_request is NULL\n",
__func__);
error = DM_REQ_CRYPT_ERROR;
goto submit_request;
}
} else {
DMERR("%s io is NULL\n",
__func__);
error = DM_REQ_CRYPT_ERROR;
goto submit_request;
}
req_crypt_inc_pending(io);
if (error != 0) {
err = error;
goto submit_request;
}
req = ablkcipher_request_alloc(tfm, GFP_KERNEL);
if (!req) {
DMERR("%s ablkcipher request allocation failed\n", __func__);
err = DM_REQ_CRYPT_ERROR;
goto ablkcipher_req_alloc_failure;
}
ablkcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
req_crypt_cipher_complete, &result);
init_completion(&result.completion);
err = qcrypto_cipher_set_device(req, FDE_CRYPTO_DEVICE);
if (err != 0) {
DMERR("%s qcrypto_cipher_set_device failed with err %d\n",
__func__, err);
error = DM_REQ_CRYPT_ERROR;
goto ablkcipher_req_alloc_failure;
}
qcrypto_cipher_set_flag(req,
QCRYPTO_CTX_USE_PIPE_KEY | QCRYPTO_CTX_XTS_DU_SIZE_512B);
crypto_ablkcipher_clear_flags(tfm, ~0);
crypto_ablkcipher_setkey(tfm, NULL, KEY_SIZE_XTS);
req_sg_read = kzalloc(sizeof(struct scatterlist) *
MAX_SG_LIST, GFP_KERNEL);
if (!req_sg_read) {
DMERR("%s req_sg_read allocation failed\n",
__func__);
err = DM_REQ_CRYPT_ERROR;
goto ablkcipher_req_alloc_failure;
}
total_sg_len = blk_rq_map_sg(clone->q, clone, req_sg_read);
if ((total_sg_len <= 0) || (total_sg_len > MAX_SG_LIST)) {
DMERR("%s Request Error%d", __func__, total_sg_len);
err = DM_REQ_CRYPT_ERROR;
goto ablkcipher_req_alloc_failure;
}
total_bytes_in_req = clone->__data_len;
if (total_bytes_in_req > REQ_DM_512_KB) {
DMERR("%s total_bytes_in_req > 512 MB %d",
__func__, total_bytes_in_req);
err = DM_REQ_CRYPT_ERROR;
goto ablkcipher_req_alloc_failure;
}
memset(IV, 0, AES_XTS_IV_LEN);
memcpy(IV, &clone->__sector, sizeof(sector_t));
ablkcipher_request_set_crypt(req, req_sg_read, req_sg_read,
total_bytes_in_req, (void *) IV);
rc = crypto_ablkcipher_decrypt(req);
switch (rc) {
case 0:
break;
case -EBUSY:
/*
* Lets make this synchronous request by waiting on
* in progress as well
*/
case -EINPROGRESS:
wait_for_completion_io(&result.completion);
if (result.err) {
DMERR("%s error = %d encrypting the request\n",
__func__, result.err);
err = DM_REQ_CRYPT_ERROR;
}
break;
default:
err = DM_REQ_CRYPT_ERROR;
break;
}
ablkcipher_req_alloc_failure:
if (req)
ablkcipher_request_free(req);
kfree(req_sg_read);
submit_request:
if (io)
io->error = err;
req_crypt_dec_pending_decrypt(io);
}
/*
* The callback that will be called by the worker queue to perform Encryption
* for writes and submit the request using the elevelator.
*/
static void req_cryptd_crypt_write_convert(struct req_dm_crypt_io *io)
{
struct request *clone = NULL;
struct bio *bio_src = NULL;
unsigned int total_sg_len_req_in = 0, total_sg_len_req_out = 0,
total_bytes_in_req = 0, error = DM_MAPIO_REMAPPED, rc = 0;
struct req_iterator iter = {0, NULL};
struct req_iterator iter1 = {0, NULL};
struct ablkcipher_request *req = NULL;
struct req_crypt_result result;
struct bio_vec *bvec = NULL;
struct scatterlist *req_sg_in = NULL;
struct scatterlist *req_sg_out = NULL;
int copy_bio_sector_to_req = 0;
gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
struct page *page = NULL;
u8 IV[AES_XTS_IV_LEN];
int remaining_size = 0;
if (io) {
if (io->cloned_request) {
clone = io->cloned_request;
} else {
DMERR("%s io->cloned_request is NULL\n",
__func__);
error = DM_REQ_CRYPT_ERROR;
goto submit_request;
}
} else {
DMERR("%s io is NULL\n",
__func__);
error = DM_REQ_CRYPT_ERROR;
goto submit_request;
}
req_crypt_inc_pending(io);
req = ablkcipher_request_alloc(tfm, GFP_KERNEL);
if (!req) {
DMERR("%s ablkcipher request allocation failed\n",
__func__);
error = DM_REQ_CRYPT_ERROR;
goto ablkcipher_req_alloc_failure;
}
ablkcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
req_crypt_cipher_complete, &result);
init_completion(&result.completion);
error = qcrypto_cipher_set_device(req, FDE_CRYPTO_DEVICE);
if (error != 0) {
DMERR("%s qcrypto_cipher_set_device failed with error %d\n",
__func__, error);
error = DM_REQ_CRYPT_ERROR;
goto ablkcipher_req_alloc_failure;
}
qcrypto_cipher_set_flag(req,
QCRYPTO_CTX_USE_PIPE_KEY | QCRYPTO_CTX_XTS_DU_SIZE_512B);
crypto_ablkcipher_clear_flags(tfm, ~0);
crypto_ablkcipher_setkey(tfm, NULL, KEY_SIZE_XTS);
req_sg_in = kzalloc(sizeof(struct scatterlist) * MAX_SG_LIST,
GFP_KERNEL);
if (!req_sg_in) {
DMERR("%s req_sg_in allocation failed\n",
__func__);
error = DM_REQ_CRYPT_ERROR;
goto ablkcipher_req_alloc_failure;
}
req_sg_out = kzalloc(sizeof(struct scatterlist) * MAX_SG_LIST,
GFP_KERNEL);
if (!req_sg_out) {
DMERR("%s req_sg_out allocation failed\n",
__func__);
error = DM_REQ_CRYPT_ERROR;
goto ablkcipher_req_alloc_failure;
}
total_sg_len_req_in = blk_rq_map_sg(clone->q, clone, req_sg_in);
if ((total_sg_len_req_in <= 0) ||
(total_sg_len_req_in > MAX_SG_LIST)) {
DMERR("%s Request Error%d", __func__, total_sg_len_req_in);
error = DM_REQ_CRYPT_ERROR;
goto ablkcipher_req_alloc_failure;
}
total_bytes_in_req = clone->__data_len;
if (total_bytes_in_req > REQ_DM_512_KB) {
DMERR("%s total_bytes_in_req > 512 MB %d",
__func__, total_bytes_in_req);
error = DM_REQ_CRYPT_ERROR;
goto ablkcipher_req_alloc_failure;
}
rq_for_each_segment(bvec, clone, iter) {
if (bvec->bv_len > remaining_size) {
page = NULL;
while (page == NULL) {
page = mempool_alloc(req_page_pool, gfp_mask);
if (!page) {
DMERR("%s Crypt page alloc failed",
__func__);
congestion_wait(BLK_RW_ASYNC, HZ/100);
}
}
bvec->bv_page = page;
bvec->bv_offset = 0;
remaining_size = PAGE_SIZE - bvec->bv_len;
if (remaining_size < 0)
BUG();
} else {
bvec->bv_page = page;
bvec->bv_offset = PAGE_SIZE - remaining_size;
remaining_size = remaining_size - bvec->bv_len;
}
}
total_sg_len_req_out = blk_rq_map_sg(clone->q, clone, req_sg_out);
if ((total_sg_len_req_out <= 0) ||
(total_sg_len_req_out > MAX_SG_LIST)) {
DMERR("%s Request Error %d", __func__, total_sg_len_req_out);
error = DM_REQ_CRYPT_ERROR_AFTER_PAGE_MALLOC;
goto ablkcipher_req_alloc_failure;
}
memset(IV, 0, AES_XTS_IV_LEN);
memcpy(IV, &clone->__sector, sizeof(sector_t));
ablkcipher_request_set_crypt(req, req_sg_in, req_sg_out,
total_bytes_in_req, (void *) IV);
rc = crypto_ablkcipher_encrypt(req);
switch (rc) {
case 0:
break;
case -EBUSY:
/*
* Lets make this synchronous request by waiting on
* in progress as well
*/
case -EINPROGRESS:
wait_for_completion_interruptible(&result.completion);
if (result.err) {
DMERR("%s error = %d encrypting the request\n",
__func__, result.err);
error = DM_REQ_CRYPT_ERROR_AFTER_PAGE_MALLOC;
goto ablkcipher_req_alloc_failure;
}
break;
default:
error = DM_REQ_CRYPT_ERROR_AFTER_PAGE_MALLOC;
goto ablkcipher_req_alloc_failure;
}
__rq_for_each_bio(bio_src, clone) {
if (copy_bio_sector_to_req == 0) {
clone->buffer = bio_data(bio_src);
copy_bio_sector_to_req++;
}
blk_queue_bounce(clone->q, &bio_src);
}
ablkcipher_req_alloc_failure:
if (req)
ablkcipher_request_free(req);
if (error == DM_REQ_CRYPT_ERROR_AFTER_PAGE_MALLOC) {
bvec = NULL;
rq_for_each_segment(bvec, clone, iter1) {
if (bvec->bv_offset == 0) {
mempool_free(bvec->bv_page, req_page_pool);
bvec->bv_page = NULL;
} else
bvec->bv_page = NULL;
}
}
kfree(req_sg_in);
kfree(req_sg_out);
submit_request:
if (io)
io->error = error;
req_crypt_dec_pending_encrypt(io);
}
/* Queue callback function that will get triggered */
static void req_cryptd_crypt(struct work_struct *work)
{
struct req_dm_crypt_io *io =
container_of(work, struct req_dm_crypt_io, work);
if (rq_data_dir(io->cloned_request) == WRITE)
req_cryptd_crypt_write_convert(io);
else if (rq_data_dir(io->cloned_request) == READ)
req_cryptd_crypt_read_convert(io);
else
DMERR("%s received non-read/write request for Clone %u\n",
__func__, (unsigned int)io->cloned_request);
}
static void req_cryptd_queue_crypt(struct req_dm_crypt_io *io)
{
INIT_WORK(&io->work, req_cryptd_crypt);
queue_work(req_crypt_queue, &io->work);
}
/*
* Cipher complete callback, this is triggered by the Linux crypto api once
* the operation is done. This signals the waiting thread that the crypto
* operation is complete.
*/
static void req_crypt_cipher_complete(struct crypto_async_request *req, int err)
{
struct req_crypt_result *res = req->data;
if (err == -EINPROGRESS)
return;
res->err = err;
complete(&res->completion);
}
/*
* If bio->bi_dev is a partition, remap the location
*/
static inline void req_crypt_blk_partition_remap(struct bio *bio)
{
struct block_device *bdev = bio->bi_bdev;
if (bio_sectors(bio) && bdev != bdev->bd_contains) {
struct hd_struct *p = bdev->bd_part;
/*
* Check for integer overflow, should never happen.
*/
if (p->start_sect > (UINT_MAX - bio->bi_sector))
BUG();
bio->bi_sector += p->start_sect;
bio->bi_bdev = bdev->bd_contains;
}
}
/*
* The endio function is called from ksoftirqd context (atomic).
* For write operations the new pages created form the mempool
* is freed and returned. * For read operations, decryption is
* required, since this is called in a atomic * context, the
* request is sent to a worker queue to complete decryptiona and
* free the request once done.
*/
static int req_crypt_endio(struct dm_target *ti, struct request *clone,
int error, union map_info *map_context)
{
int err = 0;
struct req_iterator iter1;
struct bio_vec *bvec = NULL;
struct req_dm_crypt_io *req_io = map_context->ptr;
/* If it is a write request, do nothing just return. */
bvec = NULL;
if (rq_data_dir(clone) == WRITE) {
rq_for_each_segment(bvec, clone, iter1) {
if (bvec->bv_offset == 0) {
mempool_free(bvec->bv_page, req_page_pool);
bvec->bv_page = NULL;
} else
bvec->bv_page = NULL;
}
mempool_free(req_io, req_io_pool);
goto submit_request;
} else if (rq_data_dir(clone) == READ) {
req_io->error = error;
req_cryptd_queue_crypt(req_io);
err = DM_ENDIO_INCOMPLETE;
goto submit_request;
}
submit_request:
return err;
}
/*
* This function is called with interrupts disabled
* The function remaps the clone for the underlying device.
* If it is a write request, it calls into the worker queue to
* encrypt the data
* and submit the request directly using the elevator
* For a read request no pre-processing is required the request
* is returned to dm once mapping is done
*/
static int req_crypt_map(struct dm_target *ti, struct request *clone,
union map_info *map_context)
{
struct req_dm_crypt_io *req_io = NULL;
int error = DM_REQ_CRYPT_ERROR, copy_bio_sector_to_req = 0;
struct bio *bio_src = NULL;
if ((rq_data_dir(clone) != READ) &&
(rq_data_dir(clone) != WRITE)) {
error = DM_REQ_CRYPT_ERROR;
DMERR("%s Unknown request\n", __func__);
goto submit_request;
}
req_io = mempool_alloc(req_io_pool, GFP_NOWAIT);
if (!req_io) {
DMERR("%s req_io allocation failed\n", __func__);
error = DM_REQ_CRYPT_ERROR;
goto submit_request;
}
/* Save the clone in the req_io, the callback to the worker
* queue will get the req_io
*/
req_io->cloned_request = clone;
map_context->ptr = req_io;
atomic_set(&req_io->pending, 0);
/* Get the queue of the underlying original device */
clone->q = bdev_get_queue(dev->bdev);
clone->rq_disk = dev->bdev->bd_disk;
__rq_for_each_bio(bio_src, clone) {
bio_src->bi_bdev = dev->bdev;
/* Currently the way req-dm works is that once the underlying
* device driver completes the request by calling into the
* block layer. The block layer completes the bios (clones) and
* then the cloned request. This is undesirable for req-dm-crypt
* hence added a flag BIO_DONTFREE, this flag will ensure that
* blk layer does not complete the cloned bios before completing
* the request. When the crypt endio is called, post-processsing
* is done and then the dm layer will complete the bios (clones)
* and free them.
*/
bio_src->bi_flags |= 1 << BIO_DONTFREE;
/*
* If this device has partitions, remap block n
* of partition p to block n+start(p) of the disk.
*/
req_crypt_blk_partition_remap(bio_src);
if (copy_bio_sector_to_req == 0) {
clone->__sector = bio_src->bi_sector;
clone->buffer = bio_data(bio_src);
copy_bio_sector_to_req++;
}
blk_queue_bounce(clone->q, &bio_src);
}
if (rq_data_dir(clone) == READ) {
error = DM_MAPIO_REMAPPED;
goto submit_request;
} else if (rq_data_dir(clone) == WRITE) {
req_cryptd_queue_crypt(req_io);
error = DM_MAPIO_SUBMITTED;
goto submit_request;
}
submit_request:
return error;
}
static void req_crypt_dtr(struct dm_target *ti)
{
if (req_crypt_queue) {
destroy_workqueue(req_crypt_queue);
req_crypt_queue = NULL;
}
if (req_io_pool) {
mempool_destroy(req_io_pool);
req_io_pool = NULL;
}
if (req_page_pool) {
mempool_destroy(req_page_pool);
req_page_pool = NULL;
}
if (tfm) {
crypto_free_ablkcipher(tfm);
tfm = NULL;
}
dm_put_device(ti, dev);
}
/*
* Construct an encryption mapping:
* <cipher> <key> <iv_offset> <dev_path> <start>
*/
static int req_crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
unsigned long long tmpll;
char dummy;
int err = DM_REQ_CRYPT_ERROR;
if (argc < 5) {
DMERR(" %s Not enough args\n", __func__);
err = DM_REQ_CRYPT_ERROR;
goto ctr_exit;
}
if (argv[3]) {
if (dm_get_device(ti, argv[3],
dm_table_get_mode(ti->table), &dev)) {
DMERR(" %s Device Lookup failed\n", __func__);
err = DM_REQ_CRYPT_ERROR;
goto ctr_exit;
}
} else {
DMERR(" %s Arg[3] invalid\n", __func__);
err = DM_REQ_CRYPT_ERROR;
goto ctr_exit;
}
if (argv[4]) {
if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
DMERR("%s Invalid device sector\n", __func__);
err = DM_REQ_CRYPT_ERROR;
goto ctr_exit;
}
} else {
DMERR(" %s Arg[4]invalid\n", __func__);
err = DM_REQ_CRYPT_ERROR;
goto ctr_exit;
}
start_sector_orig = tmpll;
req_crypt_queue = alloc_workqueue("req_cryptd",
WQ_NON_REENTRANT |
WQ_HIGHPRI |
WQ_CPU_INTENSIVE|
WQ_MEM_RECLAIM,
1);
if (!req_crypt_queue) {
DMERR("%s req_crypt_queue not allocated\n", __func__);
err = DM_REQ_CRYPT_ERROR;
goto ctr_exit;
}
/* Allocate the crypto alloc blk cipher and keep the handle */
tfm = crypto_alloc_ablkcipher("qcom-xts(aes)", 0, 0);
if (IS_ERR(tfm)) {
DMERR("%s ablkcipher tfm allocation failed : error\n",
__func__);
err = DM_REQ_CRYPT_ERROR;
goto ctr_exit;
}
req_io_pool = mempool_create_slab_pool(MIN_IOS, _req_crypt_io_pool);
if (!req_io_pool) {
DMERR("%s req_io_pool not allocated\n", __func__);
err = DM_REQ_CRYPT_ERROR;
goto ctr_exit;
}
req_page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
if (!req_page_pool) {
DMERR("%s req_page_pool not allocated\n", __func__);
err = DM_REQ_CRYPT_ERROR;
goto ctr_exit;
}
err = 0;
ctr_exit:
if (err != 0) {
if (req_crypt_queue) {
destroy_workqueue(req_crypt_queue);
req_crypt_queue = NULL;
}
if (req_io_pool) {
mempool_destroy(req_io_pool);
req_io_pool = NULL;
}
if (req_page_pool) {
mempool_destroy(req_page_pool);
req_page_pool = NULL;
}
if (tfm) {
crypto_free_ablkcipher(tfm);
tfm = NULL;
}
}
return err;
}
static int req_crypt_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
return fn(ti, dev, start_sector_orig, ti->len, data);
}
static struct target_type req_crypt_target = {
.name = "req-crypt",
.version = {1, 0, 0},
.module = THIS_MODULE,
.ctr = req_crypt_ctr,
.dtr = req_crypt_dtr,
.map_rq = req_crypt_map,
.rq_end_io = req_crypt_endio,
.iterate_devices = req_crypt_iterate_devices,
};
static int __init req_dm_crypt_init(void)
{
int r;
_req_crypt_io_pool = KMEM_CACHE(req_dm_crypt_io, 0);
if (!_req_crypt_io_pool)
return -ENOMEM;
r = dm_register_target(&req_crypt_target);
if (r < 0) {
DMERR("register failed %d", r);
kmem_cache_destroy(_req_crypt_io_pool);
}
return r;
}
static void __exit req_dm_crypt_exit(void)
{
kmem_cache_destroy(_req_crypt_io_pool);
dm_unregister_target(&req_crypt_target);
}
module_init(req_dm_crypt_init);
module_exit(req_dm_crypt_exit);
MODULE_DESCRIPTION(DM_NAME " target for request based transparent encryption / decryption");
MODULE_LICENSE("GPL v2");