/*
* Copyright (C) 2003 Christophe Saout <christophe@saout.de>
* Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
*
* This file is released under the GPL.
*/
#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 <asm/atomic.h>
#include <asm/scatterlist.h>
#include <asm/page.h>
#include "dm.h"
#define PFX "crypt: "
/*
* per bio private data
*/
struct crypt_io {
struct dm_target *target;
struct bio *bio;
struct bio *first_clone;
struct work_struct work;
atomic_t pending;
int error;
};
/*
* context holding the current state of a multi-part conversion
*/
struct convert_context {
struct bio *bio_in;
struct bio *bio_out;
unsigned int offset_in;
unsigned int offset_out;
unsigned int idx_in;
unsigned int idx_out;
sector_t sector;
int write;
};
struct crypt_config;
struct crypt_iv_operations {
int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
const char *opts);
void (*dtr)(struct crypt_config *cc);
const char *(*status)(struct crypt_config *cc);
int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
};
/*
* Crypt: maps a linear range of a block device
* and encrypts / decrypts at the same time.
*/
struct crypt_config {
struct dm_dev *dev;
sector_t start;
/*
* pool for per bio private data and
* for encryption buffer pages
*/
mempool_t *io_pool;
mempool_t *page_pool;
/*
* crypto related data
*/
struct crypt_iv_operations *iv_gen_ops;
char *iv_mode;
void *iv_gen_private;
sector_t iv_offset;
unsigned int iv_size;
struct crypto_tfm *tfm;
unsigned int key_size;
u8 key[0];
};
#define MIN_IOS 256
#define MIN_POOL_PAGES 32
#define MIN_BIO_PAGES 8
static kmem_cache_t *_crypt_io_pool;
/*
* Mempool alloc and free functions for the page
*/
static void *mempool_alloc_page(gfp_t gfp_mask, void *data)
{
return alloc_page(gfp_mask);
}
static void mempool_free_page(void *page, void *data)
{
__free_page(page);
}
/*
* Different IV generation algorithms:
*
* plain: the initial vector is the 32-bit low-endian version of the sector
* number, padded with zeros if neccessary.
*
* ess_iv: "encrypted sector|salt initial vector", the sector number is
* encrypted with the bulk cipher using a salt as key. The salt
* should be derived from the bulk cipher's key via hashing.
*
* plumb: unimplemented, see:
* http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
*/
static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
{
memset(iv, 0, cc->iv_size);
*(u32 *)iv = cpu_to_le32(sector & 0xffffffff);
return 0;
}
static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
const char *opts)
{
struct crypto_tfm *essiv_tfm;
struct crypto_tfm *hash_tfm;
struct scatterlist sg;
unsigned int saltsize;
u8 *salt;
if (opts == NULL) {
ti->error = PFX "Digest algorithm missing for ESSIV mode";
return -EINVAL;
}
/* Hash the cipher key with the given hash algorithm */
hash_tfm = crypto_alloc_tfm(opts, CRYPTO_TFM_REQ_MAY_SLEEP);
if (hash_tfm == NULL) {
ti->error = PFX "Error initializing ESSIV hash";
return -EINVAL;
}
if (crypto_tfm_alg_type(hash_tfm) != CRYPTO_ALG_TYPE_DIGEST) {
ti->error = PFX "Expected digest algorithm for ESSIV hash";
crypto_free_tfm(hash_tfm);
return -EINVAL;
}
saltsize = crypto_tfm_alg_digestsize(hash_tfm);
salt = kmalloc(saltsize, GFP_KERNEL);
if (salt == NULL) {
ti->error = PFX "Error kmallocing salt storage in ESSIV";
crypto_free_tfm(hash_tfm);
return -ENOMEM;
}
sg.page = virt_to_page(cc->key);
sg.offset = offset_in_page(cc->key);
sg.length = cc->key_size;
crypto_digest_digest(hash_tfm, &sg, 1, salt);
crypto_free_tfm(hash_tfm);
/* Setup the essiv_tfm with the given salt */
essiv_tfm = crypto_alloc_tfm(crypto_tfm_alg_name(cc->tfm),
CRYPTO_TFM_MODE_ECB |
CRYPTO_TFM_REQ_MAY_SLEEP);
if (essiv_tfm == NULL) {
ti->error = PFX "Error allocating crypto tfm for ESSIV";
kfree(salt);
return -EINVAL;
}
if (crypto_tfm_alg_blocksize(essiv_tfm)
!= crypto_tfm_alg_ivsize(cc->tfm)) {
ti->error = PFX "Block size of ESSIV cipher does "
"not match IV size of block cipher";
crypto_free_tfm(essiv_tfm);
kfree(salt);
return -EINVAL;
}
if (crypto_cipher_setkey(essiv_tfm, salt, saltsize) < 0) {
ti->error = PFX "Failed to set key for ESSIV cipher";
crypto_free_tfm(essiv_tfm);
kfree(salt);
return -EINVAL;
}
kfree(salt);
cc->iv_gen_private = (void *)essiv_tfm;
return 0;
}
static void crypt_iv_essiv_dtr(struct crypt_config *cc)
{
crypto_free_tfm((struct crypto_tfm *)cc->iv_gen_private);
cc->iv_gen_private = NULL;
}
static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
{
struct scatterlist sg = { NULL, };
memset(iv, 0, cc->iv_size);
*(u64 *)iv = cpu_to_le64(sector);
sg.page = virt_to_page(iv);
sg.offset = offset_in_page(iv);
sg.length = cc->iv_size;
crypto_cipher_encrypt((struct crypto_tfm *)cc->iv_gen_private,
&sg, &sg, cc->iv_size);
return 0;
}
static struct crypt_iv_operations crypt_iv_plain_ops = {
.generator = crypt_iv_plain_gen
};
static struct crypt_iv_operations crypt_iv_essiv_ops = {
.ctr = crypt_iv_essiv_ctr,
.dtr = crypt_iv_essiv_dtr,
.generator = crypt_iv_essiv_gen
};
static inline int
crypt_convert_scatterlist(struct crypt_config *cc, struct scatterlist *out,
struct scatterlist *in, unsigned int length,
int write, sector_t sector)
{
u8 iv[cc->iv_size];
int r;
if (cc->iv_gen_ops) {
r = cc->iv_gen_ops->generator(cc, iv, sector);
if (r < 0)
return r;
if (write)
r = crypto_cipher_encrypt_iv(cc->tfm, out, in, length, iv);
else
r = crypto_cipher_decrypt_iv(cc->tfm, out, in, length, iv);
} else {
if (write)
r = crypto_cipher_encrypt(cc->tfm, out, in, length);
else
r = crypto_cipher_decrypt(cc->tfm, out, in, length);
}
return r;
}
static void
crypt_convert_init(struct crypt_config *cc, struct convert_context *ctx,
struct bio *bio_out, struct bio *bio_in,
sector_t sector, int write)
{
ctx->bio_in = bio_in;
ctx->bio_out = bio_out;
ctx->offset_in = 0;
ctx->offset_out = 0;
ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
ctx->sector = sector + cc->iv_offset;
ctx->write = write;
}
/*
* Encrypt / decrypt data from one bio to another one (can be the same one)
*/
static int crypt_convert(struct crypt_config *cc,
struct convert_context *ctx)
{
int r = 0;
while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
ctx->idx_out < ctx->bio_out->bi_vcnt) {
struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
struct scatterlist sg_in = {
.page = bv_in->bv_page,
.offset = bv_in->bv_offset + ctx->offset_in,
.length = 1 << SECTOR_SHIFT
};
struct scatterlist sg_out = {
.page = bv_out->bv_page,
.offset = bv_out->bv_offset + ctx->offset_out,
.length = 1 << SECTOR_SHIFT
};
ctx->offset_in += sg_in.length;
if (ctx->offset_in >= bv_in->bv_len) {
ctx->offset_in = 0;
ctx->idx_in++;
}
ctx->offset_out += sg_out.length;
if (ctx->offset_out >= bv_out->bv_len) {
ctx->offset_out = 0;
ctx->idx_out++;
}
r = crypt_convert_scatterlist(cc, &sg_out, &sg_in, sg_in.length,
ctx->write, ctx->sector);
if (r < 0)
break;
ctx->sector++;
}
return r;
}
/*
* Generate a new unfragmented bio with the given size
* This should never violate the device limitations
* May return a smaller bio when running out of pages
*/
static struct bio *
crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
struct bio *base_bio, unsigned int *bio_vec_idx)
{
struct bio *bio;
unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
int gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
unsigned int i;
/*
* Use __GFP_NOMEMALLOC to tell the VM to act less aggressively and
* to fail earlier. This is not necessary but increases throughput.
* FIXME: Is this really intelligent?
*/
if (base_bio)
bio = bio_clone(base_bio, GFP_NOIO|__GFP_NOMEMALLOC);
else
bio = bio_alloc(GFP_NOIO|__GFP_NOMEMALLOC, nr_iovecs);
if (!bio)
return NULL;
/* if the last bio was not complete, continue where that one ended */
bio->bi_idx = *bio_vec_idx;
bio->bi_vcnt = *bio_vec_idx;
bio->bi_size = 0;
bio->bi_flags &= ~(1 << BIO_SEG_VALID);
/* bio->bi_idx pages have already been allocated */
size -= bio->bi_idx * PAGE_SIZE;
for(i = bio->bi_idx; i < nr_iovecs; i++) {
struct bio_vec *bv = bio_iovec_idx(bio, i);
bv->bv_page = mempool_alloc(cc->page_pool, gfp_mask);
if (!bv->bv_page)
break;
/*
* if additional pages cannot be allocated without waiting,
* return a partially allocated bio, the caller will then try
* to allocate additional bios while submitting this partial bio
*/
if ((i - bio->bi_idx) == (MIN_BIO_PAGES - 1))
gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
bv->bv_offset = 0;
if (size > PAGE_SIZE)
bv->bv_len = PAGE_SIZE;
else
bv->bv_len = size;
bio->bi_size += bv->bv_len;
bio->bi_vcnt++;
size -= bv->bv_len;
}
if (!bio->bi_size) {
bio_put(bio);
return NULL;
}
/*
* Remember the last bio_vec allocated to be able
* to correctly continue after the splitting.
*/
*bio_vec_idx = bio->bi_vcnt;
return bio;
}
static void crypt_free_buffer_pages(struct crypt_config *cc,
struct bio *bio, unsigned int bytes)
{
unsigned int i, start, end;
struct bio_vec *bv;
/*
* This is ugly, but Jens Axboe thinks that using bi_idx in the
* endio function is too dangerous at the moment, so I calculate the
* correct position using bi_vcnt and bi_size.
* The bv_offset and bv_len fields might already be modified but we
* know that we always allocated whole pages.
* A fix to the bi_idx issue in the kernel is in the works, so
* we will hopefully be able to revert to the cleaner solution soon.
*/
i = bio->bi_vcnt - 1;
bv = bio_iovec_idx(bio, i);
end = (i << PAGE_SHIFT) + (bv->bv_offset + bv->bv_len) - bio->bi_size;
start = end - bytes;
start >>= PAGE_SHIFT;
if (!bio->bi_size)
end = bio->bi_vcnt;
else
end >>= PAGE_SHIFT;
for(i = start; i < end; i++) {
bv = bio_iovec_idx(bio, i);
BUG_ON(!bv->bv_page);
mempool_free(bv->bv_page, cc->page_pool);
bv->bv_page = NULL;
}
}
/*
* One of the bios was finished. Check for completion of
* the whole request and correctly clean up the buffer.
*/
static void dec_pending(struct crypt_io *io, int error)
{
struct crypt_config *cc = (struct crypt_config *) io->target->private;
if (error < 0)
io->error = error;
if (!atomic_dec_and_test(&io->pending))
return;
if (io->first_clone)
bio_put(io->first_clone);
bio_endio(io->bio, io->bio->bi_size, io->error);
mempool_free(io, cc->io_pool);
}
/*
* kcryptd:
*
* Needed because it would be very unwise to do decryption in an
* interrupt context, so bios returning from read requests get
* queued here.
*/
static struct workqueue_struct *_kcryptd_workqueue;
static void kcryptd_do_work(void *data)
{
struct crypt_io *io = (struct crypt_io *) data;
struct crypt_config *cc = (struct crypt_config *) io->target->private;
struct convert_context ctx;
int r;
crypt_convert_init(cc, &ctx, io->bio, io->bio,
io->bio->bi_sector - io->target->begin, 0);
r = crypt_convert(cc, &ctx);
dec_pending(io, r);
}
static void kcryptd_queue_io(struct crypt_io *io)
{
INIT_WORK(&io->work, kcryptd_do_work, io);
queue_work(_kcryptd_workqueue, &io->work);
}
/*
* Decode key from its hex representation
*/
static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
{
char buffer[3];
char *endp;
unsigned int i;
buffer[2] = '\0';
for(i = 0; i < size; i++) {
buffer[0] = *hex++;
buffer[1] = *hex++;
key[i] = (u8)simple_strtoul(buffer, &endp, 16);
if (endp != &buffer[2])
return -EINVAL;
}
if (*hex != '\0')
return -EINVAL;
return 0;
}
/*
* Encode key into its hex representation
*/
static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
{
unsigned int i;
for(i = 0; i < size; i++) {
sprintf(hex, "%02x", *key);
hex += 2;
key++;
}
}
/*
* Construct an encryption mapping:
* <cipher> <key> <iv_offset> <dev_path> <start>
*/
static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
struct crypt_config *cc;
struct crypto_tfm *tfm;
char *tmp;
char *cipher;
char *chainmode;
char *ivmode;
char *ivopts;
unsigned int crypto_flags;
unsigned int key_size;
if (argc != 5) {
ti->error = PFX "Not enough arguments";
return -EINVAL;
}
tmp = argv[0];
cipher = strsep(&tmp, "-");
chainmode = strsep(&tmp, "-");
ivopts = strsep(&tmp, "-");
ivmode = strsep(&ivopts, ":");
if (tmp)
DMWARN(PFX "Unexpected additional cipher options");
key_size = strlen(argv[1]) >> 1;
cc = kmalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
if (cc == NULL) {
ti->error =
PFX "Cannot allocate transparent encryption context";
return -ENOMEM;
}
cc->key_size = key_size;
if ((!key_size && strcmp(argv[1], "-") != 0) ||
(key_size && crypt_decode_key(cc->key, argv[1], key_size) < 0)) {
ti->error = PFX "Error decoding key";
goto bad1;
}
/* Compatiblity mode for old dm-crypt cipher strings */
if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
chainmode = "cbc";
ivmode = "plain";
}
/* Choose crypto_flags according to chainmode */
if (strcmp(chainmode, "cbc") == 0)
crypto_flags = CRYPTO_TFM_MODE_CBC;
else if (strcmp(chainmode, "ecb") == 0)
crypto_flags = CRYPTO_TFM_MODE_ECB;
else {
ti->error = PFX "Unknown chaining mode";
goto bad1;
}
if (crypto_flags != CRYPTO_TFM_MODE_ECB && !ivmode) {
ti->error = PFX "This chaining mode requires an IV mechanism";
goto bad1;
}
tfm = crypto_alloc_tfm(cipher, crypto_flags | CRYPTO_TFM_REQ_MAY_SLEEP);
if (!tfm) {
ti->error = PFX "Error allocating crypto tfm";
goto bad1;
}
if (crypto_tfm_alg_type(tfm) != CRYPTO_ALG_TYPE_CIPHER) {
ti->error = PFX "Expected cipher algorithm";
goto bad2;
}
cc->tfm = tfm;
/*
* Choose ivmode. Valid modes: "plain", "essiv:<esshash>".
* See comments at iv code
*/
if (ivmode == NULL)
cc->iv_gen_ops = NULL;
else if (strcmp(ivmode, "plain") == 0)
cc->iv_gen_ops = &crypt_iv_plain_ops;
else if (strcmp(ivmode, "essiv") == 0)
cc->iv_gen_ops = &crypt_iv_essiv_ops;
else {
ti->error = PFX "Invalid IV mode";
goto bad2;
}
if (cc->iv_gen_ops && cc->iv_gen_ops->ctr &&
cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
goto bad2;
if (tfm->crt_cipher.cit_decrypt_iv && tfm->crt_cipher.cit_encrypt_iv)
/* at least a 64 bit sector number should fit in our buffer */
cc->iv_size = max(crypto_tfm_alg_ivsize(tfm),
(unsigned int)(sizeof(u64) / sizeof(u8)));
else {
cc->iv_size = 0;
if (cc->iv_gen_ops) {
DMWARN(PFX "Selected cipher does not support IVs");
if (cc->iv_gen_ops->dtr)
cc->iv_gen_ops->dtr(cc);
cc->iv_gen_ops = NULL;
}
}
cc->io_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
mempool_free_slab, _crypt_io_pool);
if (!cc->io_pool) {
ti->error = PFX "Cannot allocate crypt io mempool";
goto bad3;
}
cc->page_pool = mempool_create(MIN_POOL_PAGES, mempool_alloc_page,
mempool_free_page, NULL);
if (!cc->page_pool) {
ti->error = PFX "Cannot allocate page mempool";
goto bad4;
}
if (tfm->crt_cipher.cit_setkey(tfm, cc->key, key_size) < 0) {
ti->error = PFX "Error setting key";
goto bad5;
}
if (sscanf(argv[2], SECTOR_FORMAT, &cc->iv_offset) != 1) {
ti->error = PFX "Invalid iv_offset sector";
goto bad5;
}
if (sscanf(argv[4], SECTOR_FORMAT, &cc->start) != 1) {
ti->error = PFX "Invalid device sector";
goto bad5;
}
if (dm_get_device(ti, argv[3], cc->start, ti->len,
dm_table_get_mode(ti->table), &cc->dev)) {
ti->error = PFX "Device lookup failed";
goto bad5;
}
if (ivmode && cc->iv_gen_ops) {
if (ivopts)
*(ivopts - 1) = ':';
cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL);
if (!cc->iv_mode) {
ti->error = PFX "Error kmallocing iv_mode string";
goto bad5;
}
strcpy(cc->iv_mode, ivmode);
} else
cc->iv_mode = NULL;
ti->private = cc;
return 0;
bad5:
mempool_destroy(cc->page_pool);
bad4:
mempool_destroy(cc->io_pool);
bad3:
if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
cc->iv_gen_ops->dtr(cc);
bad2:
crypto_free_tfm(tfm);
bad1:
kfree(cc);
return -EINVAL;
}
static void crypt_dtr(struct dm_target *ti)
{
struct crypt_config *cc = (struct crypt_config *) ti->private;
mempool_destroy(cc->page_pool);
mempool_destroy(cc->io_pool);
kfree(cc->iv_mode);
if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
cc->iv_gen_ops->dtr(cc);
crypto_free_tfm(cc->tfm);
dm_put_device(ti, cc->dev);
kfree(cc);
}
static int crypt_endio(struct bio *bio, unsigned int done, int error)
{
struct crypt_io *io = (struct crypt_io *) bio->bi_private;
struct crypt_config *cc = (struct crypt_config *) io->target->private;
if (bio_data_dir(bio) == WRITE) {
/*
* free the processed pages, even if
* it's only a partially completed write
*/
crypt_free_buffer_pages(cc, bio, done);
}
if (bio->bi_size)
return 1;
bio_put(bio);
/*
* successful reads are decrypted by the worker thread
*/
if ((bio_data_dir(bio) == READ)
&& bio_flagged(bio, BIO_UPTODATE)) {
kcryptd_queue_io(io);
return 0;
}
dec_pending(io, error);
return error;
}
static inline struct bio *
crypt_clone(struct crypt_config *cc, struct crypt_io *io, struct bio *bio,
sector_t sector, unsigned int *bvec_idx,
struct convert_context *ctx)
{
struct bio *clone;
if (bio_data_dir(bio) == WRITE) {
clone = crypt_alloc_buffer(cc, bio->bi_size,
io->first_clone, bvec_idx);
if (clone) {
ctx->bio_out = clone;
if (crypt_convert(cc, ctx) < 0) {
crypt_free_buffer_pages(cc, clone,
clone->bi_size);
bio_put(clone);
return NULL;
}
}
} else {
/*
* The block layer might modify the bvec array, so always
* copy the required bvecs because we need the original
* one in order to decrypt the whole bio data *afterwards*.
*/
clone = bio_alloc(GFP_NOIO, bio_segments(bio));
if (clone) {
clone->bi_idx = 0;
clone->bi_vcnt = bio_segments(bio);
clone->bi_size = bio->bi_size;
memcpy(clone->bi_io_vec, bio_iovec(bio),
sizeof(struct bio_vec) * clone->bi_vcnt);
}
}
if (!clone)
return NULL;
clone->bi_private = io;
clone->bi_end_io = crypt_endio;
clone->bi_bdev = cc->dev->bdev;
clone->bi_sector = cc->start + sector;
clone->bi_rw = bio->bi_rw;
return clone;
}
static int crypt_map(struct dm_target *ti, struct bio *bio,
union map_info *map_context)
{
struct crypt_config *cc = (struct crypt_config *) ti->private;
struct crypt_io *io = mempool_alloc(cc->io_pool, GFP_NOIO);
struct convert_context ctx;
struct bio *clone;
unsigned int remaining = bio->bi_size;
sector_t sector = bio->bi_sector - ti->begin;
unsigned int bvec_idx = 0;
io->target = ti;
io->bio = bio;
io->first_clone = NULL;
io->error = 0;
atomic_set(&io->pending, 1); /* hold a reference */
if (bio_data_dir(bio) == WRITE)
crypt_convert_init(cc, &ctx, NULL, bio, sector, 1);
/*
* The allocated buffers can be smaller than the whole bio,
* so repeat the whole process until all the data can be handled.
*/
while (remaining) {
clone = crypt_clone(cc, io, bio, sector, &bvec_idx, &ctx);
if (!clone)
goto cleanup;
if (!io->first_clone) {
/*
* hold a reference to the first clone, because it
* holds the bio_vec array and that can't be freed
* before all other clones are released
*/
bio_get(clone);
io->first_clone = clone;
}
atomic_inc(&io->pending);
remaining -= clone->bi_size;
sector += bio_sectors(clone);
generic_make_request(clone);
/* out of memory -> run queues */
if (remaining)
blk_congestion_wait(bio_data_dir(clone), HZ/100);
}
/* drop reference, clones could have returned before we reach this */
dec_pending(io, 0);
return 0;
cleanup:
if (io->first_clone) {
dec_pending(io, -ENOMEM);
return 0;
}
/* if no bio has been dispatched yet, we can directly return the error */
mempool_free(io, cc->io_pool);
return -ENOMEM;
}
static int crypt_status(struct dm_target *ti, status_type_t type,
char *result, unsigned int maxlen)
{
struct crypt_config *cc = (struct crypt_config *) ti->private;
const char *cipher;
const char *chainmode = NULL;
unsigned int sz = 0;
switch (type) {
case STATUSTYPE_INFO:
result[0] = '\0';
break;
case STATUSTYPE_TABLE:
cipher = crypto_tfm_alg_name(cc->tfm);
switch(cc->tfm->crt_cipher.cit_mode) {
case CRYPTO_TFM_MODE_CBC:
chainmode = "cbc";
break;
case CRYPTO_TFM_MODE_ECB:
chainmode = "ecb";
break;
default:
BUG();
}
if (cc->iv_mode)
DMEMIT("%s-%s-%s ", cipher, chainmode, cc->iv_mode);
else
DMEMIT("%s-%s ", cipher, chainmode);
if (cc->key_size > 0) {
if ((maxlen - sz) < ((cc->key_size << 1) + 1))
return -ENOMEM;
crypt_encode_key(result + sz, cc->key, cc->key_size);
sz += cc->key_size << 1;
} else {
if (sz >= maxlen)
return -ENOMEM;
result[sz++] = '-';
}
DMEMIT(" " SECTOR_FORMAT " %s " SECTOR_FORMAT,
cc->iv_offset, cc->dev->name, cc->start);
break;
}
return 0;
}
static struct target_type crypt_target = {
.name = "crypt",
.version= {1, 1, 0},
.module = THIS_MODULE,
.ctr = crypt_ctr,
.dtr = crypt_dtr,
.map = crypt_map,
.status = crypt_status,
};
static int __init dm_crypt_init(void)
{
int r;
_crypt_io_pool = kmem_cache_create("dm-crypt_io",
sizeof(struct crypt_io),
0, 0, NULL, NULL);
if (!_crypt_io_pool)
return -ENOMEM;
_kcryptd_workqueue = create_workqueue("kcryptd");
if (!_kcryptd_workqueue) {
r = -ENOMEM;
DMERR(PFX "couldn't create kcryptd");
goto bad1;
}
r = dm_register_target(&crypt_target);
if (r < 0) {
DMERR(PFX "register failed %d", r);
goto bad2;
}
return 0;
bad2:
destroy_workqueue(_kcryptd_workqueue);
bad1:
kmem_cache_destroy(_crypt_io_pool);
return r;
}
static void __exit dm_crypt_exit(void)
{
int r = dm_unregister_target(&crypt_target);
if (r < 0)
DMERR(PFX "unregister failed %d", r);
destroy_workqueue(_kcryptd_workqueue);
kmem_cache_destroy(_crypt_io_pool);
}
module_init(dm_crypt_init);
module_exit(dm_crypt_exit);
MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
MODULE_LICENSE("GPL");
