UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity
OpenCloudOS-Kernel/drivers/md/dm-crypt.c

1121 lines
26 KiB
C
Raw Blame History

/*
* Copyright (C) 2003 Christophe Saout <christophe@saout.de>
* Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
* Copyright (C) 2006 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
#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 <asm/atomic.h>
#include <linux/scatterlist.h>
#include <asm/page.h>
#include <asm/unaligned.h>
#include "dm.h"
#define DM_MSG_PREFIX "crypt"
#define MESG_STR(x) x, sizeof(x)
/*
* per bio private data
*/
struct crypt_io {
struct dm_target *target;
struct bio *base_bio;
struct bio *first_clone;
struct work_struct work;
atomic_t pending;
int error;
int post_process;
};
/*
* 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.
*/
enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
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;
struct bio_set *bs;
/*
* crypto related data
*/
struct crypt_iv_operations *iv_gen_ops;
char *iv_mode;
union {
struct crypto_cipher *essiv_tfm;
int benbi_shift;
} iv_gen_private;
sector_t iv_offset;
unsigned int iv_size;
char cipher[CRYPTO_MAX_ALG_NAME];
char chainmode[CRYPTO_MAX_ALG_NAME];
struct crypto_blkcipher *tfm;
unsigned long flags;
unsigned int key_size;
u8 key[0];
};
#define MIN_IOS 16
#define MIN_POOL_PAGES 32
#define MIN_BIO_PAGES 8
static struct kmem_cache *_crypt_io_pool;
/*
* Different IV generation algorithms:
*
* plain: the initial vector is the 32-bit little-endian version of the sector
* number, padded with zeros if neccessary.
*
* essiv: "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.
*
* benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
* (needed for LRW-32-AES and possible other narrow block modes)
*
* 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_cipher *essiv_tfm;
struct crypto_hash *hash_tfm;
struct hash_desc desc;
struct scatterlist sg;
unsigned int saltsize;
u8 *salt;
int err;
if (opts == NULL) {
ti->error = "Digest algorithm missing for ESSIV mode";
return -EINVAL;
}
/* Hash the cipher key with the given hash algorithm */
hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(hash_tfm)) {
ti->error = "Error initializing ESSIV hash";
return PTR_ERR(hash_tfm);
}
saltsize = crypto_hash_digestsize(hash_tfm);
salt = kmalloc(saltsize, GFP_KERNEL);
if (salt == NULL) {
ti->error = "Error kmallocing salt storage in ESSIV";
crypto_free_hash(hash_tfm);
return -ENOMEM;
}
sg_set_buf(&sg, cc->key, cc->key_size);
desc.tfm = hash_tfm;
desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
err = crypto_hash_digest(&desc, &sg, cc->key_size, salt);
crypto_free_hash(hash_tfm);
if (err) {
ti->error = "Error calculating hash in ESSIV";
return err;
}
/* Setup the essiv_tfm with the given salt */
essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(essiv_tfm)) {
ti->error = "Error allocating crypto tfm for ESSIV";
kfree(salt);
return PTR_ERR(essiv_tfm);
}
if (crypto_cipher_blocksize(essiv_tfm) !=
crypto_blkcipher_ivsize(cc->tfm)) {
ti->error = "Block size of ESSIV cipher does "
"not match IV size of block cipher";
crypto_free_cipher(essiv_tfm);
kfree(salt);
return -EINVAL;
}
err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
if (err) {
ti->error = "Failed to set key for ESSIV cipher";
crypto_free_cipher(essiv_tfm);
kfree(salt);
return err;
}
kfree(salt);
cc->iv_gen_private.essiv_tfm = essiv_tfm;
return 0;
}
static void crypt_iv_essiv_dtr(struct crypt_config *cc)
{
crypto_free_cipher(cc->iv_gen_private.essiv_tfm);
cc->iv_gen_private.essiv_tfm = NULL;
}
static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
{
memset(iv, 0, cc->iv_size);
*(u64 *)iv = cpu_to_le64(sector);
crypto_cipher_encrypt_one(cc->iv_gen_private.essiv_tfm, iv, iv);
return 0;
}
static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
const char *opts)
{
unsigned int bs = crypto_blkcipher_blocksize(cc->tfm);
int log = ilog2(bs);
/* we need to calculate how far we must shift the sector count
* to get the cipher block count, we use this shift in _gen */
if (1 << log != bs) {
ti->error = "cypher blocksize is not a power of 2";
return -EINVAL;
}
if (log > 9) {
ti->error = "cypher blocksize is > 512";
return -EINVAL;
}
cc->iv_gen_private.benbi_shift = 9 - log;
return 0;
}
static void crypt_iv_benbi_dtr(struct crypt_config *cc)
{
}
static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
{
__be64 val;
memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
val = cpu_to_be64(((u64)sector << cc->iv_gen_private.benbi_shift) + 1);
put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
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 struct crypt_iv_operations crypt_iv_benbi_ops = {
.ctr = crypt_iv_benbi_ctr,
.dtr = crypt_iv_benbi_dtr,
.generator = crypt_iv_benbi_gen
};
static 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] __attribute__ ((aligned(__alignof__(u64))));
struct blkcipher_desc desc = {
.tfm = cc->tfm,
.info = iv,
.flags = CRYPTO_TFM_REQ_MAY_SLEEP,
};
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_blkcipher_encrypt_iv(&desc, out, in, length);
else
r = crypto_blkcipher_decrypt_iv(&desc, out, in, length);
} else {
if (write)
r = crypto_blkcipher_encrypt(&desc, out, in, length);
else
r = crypto_blkcipher_decrypt(&desc, 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;
}
static void dm_crypt_bio_destructor(struct bio *bio)
{
struct crypt_io *io = bio->bi_private;
struct crypt_config *cc = io->target->private;
bio_free(bio, cc->bs);
}
/*
* 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 *clone;
unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
unsigned int i;
if (base_bio) {
clone = bio_alloc_bioset(GFP_NOIO, base_bio->bi_max_vecs, cc->bs);
__bio_clone(clone, base_bio);
} else
clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
if (!clone)
return NULL;
clone->bi_destructor = dm_crypt_bio_destructor;
/* if the last bio was not complete, continue where that one ended */
clone->bi_idx = *bio_vec_idx;
clone->bi_vcnt = *bio_vec_idx;
clone->bi_size = 0;
clone->bi_flags &= ~(1 << BIO_SEG_VALID);
/* clone->bi_idx pages have already been allocated */
size -= clone->bi_idx * PAGE_SIZE;
for (i = clone->bi_idx; i < nr_iovecs; i++) {
struct bio_vec *bv = bio_iovec_idx(clone, 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 - clone->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;
clone->bi_size += bv->bv_len;
clone->bi_vcnt++;
size -= bv->bv_len;
}
if (!clone->bi_size) {
bio_put(clone);
return NULL;
}
/*
* Remember the last bio_vec allocated to be able
* to correctly continue after the splitting.
*/
*bio_vec_idx = clone->bi_vcnt;
return clone;
}
static void crypt_free_buffer_pages(struct crypt_config *cc,
struct bio *clone, 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 = clone->bi_vcnt - 1;
bv = bio_iovec_idx(clone, i);
end = (i << PAGE_SHIFT) + (bv->bv_offset + bv->bv_len) - clone->bi_size;
start = end - bytes;
start >>= PAGE_SHIFT;
if (!clone->bi_size)
end = clone->bi_vcnt;
else
end >>= PAGE_SHIFT;
for (i = start; i < end; i++) {
bv = bio_iovec_idx(clone, 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->base_bio, io->base_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.
*/
static struct workqueue_struct *_kcryptd_workqueue;
static void kcryptd_do_work(struct work_struct *work);
static void kcryptd_queue_io(struct crypt_io *io)
{
INIT_WORK(&io->work, kcryptd_do_work);
queue_work(_kcryptd_workqueue, &io->work);
}
static int crypt_endio(struct bio *clone, unsigned int done, int error)
{
struct crypt_io *io = clone->bi_private;
struct crypt_config *cc = io->target->private;
unsigned read_io = bio_data_dir(clone) == READ;
/*
* free the processed pages, even if
* it's only a partially completed write
*/
if (!read_io)
crypt_free_buffer_pages(cc, clone, done);
/* keep going - not finished yet */
if (unlikely(clone->bi_size))
return 1;
if (!read_io)
goto out;
if (unlikely(!bio_flagged(clone, BIO_UPTODATE))) {
error = -EIO;
goto out;
}
bio_put(clone);
io->post_process = 1;
kcryptd_queue_io(io);
return 0;
out:
bio_put(clone);
dec_pending(io, error);
return error;
}
static void clone_init(struct crypt_io *io, struct bio *clone)
{
struct crypt_config *cc = io->target->private;
clone->bi_private = io;
clone->bi_end_io = crypt_endio;
clone->bi_bdev = cc->dev->bdev;
clone->bi_rw = io->base_bio->bi_rw;
}
static void process_read(struct crypt_io *io)
{
struct crypt_config *cc = io->target->private;
struct bio *base_bio = io->base_bio;
struct bio *clone;
sector_t sector = base_bio->bi_sector - io->target->begin;
atomic_inc(&io->pending);
/*
* 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_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs);
if (unlikely(!clone)) {
dec_pending(io, -ENOMEM);
return;
}
clone_init(io, clone);
clone->bi_destructor = dm_crypt_bio_destructor;
clone->bi_idx = 0;
clone->bi_vcnt = bio_segments(base_bio);
clone->bi_size = base_bio->bi_size;
clone->bi_sector = cc->start + sector;
memcpy(clone->bi_io_vec, bio_iovec(base_bio),
sizeof(struct bio_vec) * clone->bi_vcnt);
generic_make_request(clone);
}
static void process_write(struct crypt_io *io)
{
struct crypt_config *cc = io->target->private;
struct bio *base_bio = io->base_bio;
struct bio *clone;
struct convert_context ctx;
unsigned remaining = base_bio->bi_size;
sector_t sector = base_bio->bi_sector - io->target->begin;
unsigned bvec_idx = 0;
atomic_inc(&io->pending);
crypt_convert_init(cc, &ctx, NULL, base_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_alloc_buffer(cc, base_bio->bi_size,
io->first_clone, &bvec_idx);
if (unlikely(!clone)) {
dec_pending(io, -ENOMEM);
return;
}
ctx.bio_out = clone;
if (unlikely(crypt_convert(cc, &ctx) < 0)) {
crypt_free_buffer_pages(cc, clone, clone->bi_size);
bio_put(clone);
dec_pending(io, -EIO);
return;
}
clone_init(io, clone);
clone->bi_sector = cc->start + sector;
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;
}
remaining -= clone->bi_size;
sector += bio_sectors(clone);
/* prevent bio_put of first_clone */
if (remaining)
atomic_inc(&io->pending);
generic_make_request(clone);
/* out of memory -> run queues */
if (remaining)
congestion_wait(bio_data_dir(clone), HZ/100);
}
}
static void process_read_endio(struct crypt_io *io)
{
struct crypt_config *cc = io->target->private;
struct convert_context ctx;
crypt_convert_init(cc, &ctx, io->base_bio, io->base_bio,
io->base_bio->bi_sector - io->target->begin, 0);
dec_pending(io, crypt_convert(cc, &ctx));
}
static void kcryptd_do_work(struct work_struct *work)
{
struct crypt_io *io = container_of(work, struct crypt_io, work);
if (io->post_process)
process_read_endio(io);
else if (bio_data_dir(io->base_bio) == READ)
process_read(io);
else
process_write(io);
}
/*
* 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++;
}
}
static int crypt_set_key(struct crypt_config *cc, char *key)
{
unsigned key_size = strlen(key) >> 1;
if (cc->key_size && cc->key_size != key_size)
return -EINVAL;
cc->key_size = key_size; /* initial settings */
if ((!key_size && strcmp(key, "-")) ||
(key_size && crypt_decode_key(cc->key, key, key_size) < 0))
return -EINVAL;
set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
return 0;
}
static int crypt_wipe_key(struct crypt_config *cc)
{
clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
memset(&cc->key, 0, cc->key_size * sizeof(u8));
return 0;
}
/*
* 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_blkcipher *tfm;
char *tmp;
char *cipher;
char *chainmode;
char *ivmode;
char *ivopts;
unsigned int key_size;
unsigned long long tmpll;
if (argc != 5) {
ti->error = "Not enough arguments";
return -EINVAL;
}
tmp = argv[0];
cipher = strsep(&tmp, "-");
chainmode = strsep(&tmp, "-");
ivopts = strsep(&tmp, "-");
ivmode = strsep(&ivopts, ":");
if (tmp)
DMWARN("Unexpected additional cipher options");
key_size = strlen(argv[1]) >> 1;
cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
if (cc == NULL) {
ti->error =
"Cannot allocate transparent encryption context";
return -ENOMEM;
}
if (crypt_set_key(cc, argv[1])) {
ti->error = "Error decoding key";
goto bad1;
}
/* Compatiblity mode for old dm-crypt cipher strings */
if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
chainmode = "cbc";
ivmode = "plain";
}
if (strcmp(chainmode, "ecb") && !ivmode) {
ti->error = "This chaining mode requires an IV mechanism";
goto bad1;
}
if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)", chainmode,
cipher) >= CRYPTO_MAX_ALG_NAME) {
ti->error = "Chain mode + cipher name is too long";
goto bad1;
}
tfm = crypto_alloc_blkcipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(tfm)) {
ti->error = "Error allocating crypto tfm";
goto bad1;
}
strcpy(cc->cipher, cipher);
strcpy(cc->chainmode, chainmode);
cc->tfm = tfm;
/*
* Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi".
* 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 if (strcmp(ivmode, "benbi") == 0)
cc->iv_gen_ops = &crypt_iv_benbi_ops;
else {
ti->error = "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;
cc->iv_size = crypto_blkcipher_ivsize(tfm);
if (cc->iv_size)
/* at least a 64 bit sector number should fit in our buffer */
cc->iv_size = max(cc->iv_size,
(unsigned int)(sizeof(u64) / sizeof(u8)));
else {
if (cc->iv_gen_ops) {
DMWARN("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_slab_pool(MIN_IOS, _crypt_io_pool);
if (!cc->io_pool) {
ti->error = "Cannot allocate crypt io mempool";
goto bad3;
}
cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
if (!cc->page_pool) {
ti->error = "Cannot allocate page mempool";
goto bad4;
}
cc->bs = bioset_create(MIN_IOS, MIN_IOS, 4);
if (!cc->bs) {
ti->error = "Cannot allocate crypt bioset";
goto bad_bs;
}
if (crypto_blkcipher_setkey(tfm, cc->key, key_size) < 0) {
ti->error = "Error setting key";
goto bad5;
}
if (sscanf(argv[2], "%llu", &tmpll) != 1) {
ti->error = "Invalid iv_offset sector";
goto bad5;
}
cc->iv_offset = tmpll;
if (sscanf(argv[4], "%llu", &tmpll) != 1) {
ti->error = "Invalid device sector";
goto bad5;
}
cc->start = tmpll;
if (dm_get_device(ti, argv[3], cc->start, ti->len,
dm_table_get_mode(ti->table), &cc->dev)) {
ti->error = "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 = "Error kmallocing iv_mode string";
goto bad5;
}
strcpy(cc->iv_mode, ivmode);
} else
cc->iv_mode = NULL;
ti->private = cc;
return 0;
bad5:
bioset_free(cc->bs);
bad_bs:
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_blkcipher(tfm);
bad1:
/* Must zero key material before freeing */
memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
kfree(cc);
return -EINVAL;
}
static void crypt_dtr(struct dm_target *ti)
{
struct crypt_config *cc = (struct crypt_config *) ti->private;
bioset_free(cc->bs);
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_blkcipher(cc->tfm);
dm_put_device(ti, cc->dev);
/* Must zero key material before freeing */
memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
kfree(cc);
}
static int crypt_map(struct dm_target *ti, struct bio *bio,
union map_info *map_context)
{
struct crypt_config *cc = ti->private;
struct crypt_io *io;
io = mempool_alloc(cc->io_pool, GFP_NOIO);
io->target = ti;
io->base_bio = bio;
io->first_clone = NULL;
io->error = io->post_process = 0;
atomic_set(&io->pending, 0);
kcryptd_queue_io(io);
return DM_MAPIO_SUBMITTED;
}
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;
unsigned int sz = 0;
switch (type) {
case STATUSTYPE_INFO:
result[0] = '\0';
break;
case STATUSTYPE_TABLE:
if (cc->iv_mode)
DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode,
cc->iv_mode);
else
DMEMIT("%s-%s ", cc->cipher, cc->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(" %llu %s %llu", (unsigned long long)cc->iv_offset,
cc->dev->name, (unsigned long long)cc->start);
break;
}
return 0;
}
static void crypt_postsuspend(struct dm_target *ti)
{
struct crypt_config *cc = ti->private;
set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
}
static int crypt_preresume(struct dm_target *ti)
{
struct crypt_config *cc = ti->private;
if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
DMERR("aborting resume - crypt key is not set.");
return -EAGAIN;
}
return 0;
}
static void crypt_resume(struct dm_target *ti)
{
struct crypt_config *cc = ti->private;
clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
}
/* Message interface
* key set <key>
* key wipe
*/
static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
{
struct crypt_config *cc = ti->private;
if (argc < 2)
goto error;
if (!strnicmp(argv[0], MESG_STR("key"))) {
if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
DMWARN("not suspended during key manipulation.");
return -EINVAL;
}
if (argc == 3 && !strnicmp(argv[1], MESG_STR("set")))
return crypt_set_key(cc, argv[2]);
if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe")))
return crypt_wipe_key(cc);
}
error:
DMWARN("unrecognised message received.");
return -EINVAL;
}
static struct target_type crypt_target = {
.name = "crypt",
.version= {1, 3, 0},
.module = THIS_MODULE,
.ctr = crypt_ctr,
.dtr = crypt_dtr,
.map = crypt_map,
.status = crypt_status,
.postsuspend = crypt_postsuspend,
.preresume = crypt_preresume,
.resume = crypt_resume,
.message = crypt_message,
};
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("couldn't create kcryptd");
goto bad1;
}
r = dm_register_target(&crypt_target);
if (r < 0) {
DMERR("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("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");
Reference in New Issue View Git Blame Copy Permalink