2 * Copyright (C) 2003 Christophe Saout <christophe@saout.de>
3 * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
4 * Copyright (C) 2006-2008 Red Hat, Inc. All rights reserved.
6 * This file is released under the GPL.
9 #include <linux/completion.h>
10 #include <linux/err.h>
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/bio.h>
15 #include <linux/blkdev.h>
16 #include <linux/mempool.h>
17 #include <linux/slab.h>
18 #include <linux/crypto.h>
19 #include <linux/workqueue.h>
20 #include <linux/backing-dev.h>
21 #include <asm/atomic.h>
22 #include <linux/scatterlist.h>
24 #include <asm/unaligned.h>
28 #define DM_MSG_PREFIX "crypt"
29 #define MESG_STR(x) x, sizeof(x)
32 * context holding the current state of a multi-part conversion
34 struct convert_context {
35 struct completion restart;
38 unsigned int offset_in;
39 unsigned int offset_out;
47 * per bio private data
50 struct dm_target *target;
52 struct work_struct work;
54 struct convert_context ctx;
61 struct dm_crypt_request {
62 struct scatterlist sg_in;
63 struct scatterlist sg_out;
68 struct crypt_iv_operations {
69 int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
71 void (*dtr)(struct crypt_config *cc);
72 const char *(*status)(struct crypt_config *cc);
73 int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
77 * Crypt: maps a linear range of a block device
78 * and encrypts / decrypts at the same time.
80 enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
86 * pool for per bio private data, crypto requests and
87 * encryption requeusts/buffer pages
94 struct workqueue_struct *io_queue;
95 struct workqueue_struct *crypt_queue;
96 wait_queue_head_t writeq;
101 struct crypt_iv_operations *iv_gen_ops;
104 struct crypto_cipher *essiv_tfm;
108 unsigned int iv_size;
111 * Layout of each crypto request:
113 * struct ablkcipher_request
116 * struct dm_crypt_request
120 * The padding is added so that dm_crypt_request and the IV are
123 unsigned int dmreq_start;
124 struct ablkcipher_request *req;
126 char cipher[CRYPTO_MAX_ALG_NAME];
127 char chainmode[CRYPTO_MAX_ALG_NAME];
128 struct crypto_ablkcipher *tfm;
130 unsigned int key_size;
135 #define MIN_POOL_PAGES 32
136 #define MIN_BIO_PAGES 8
138 static struct kmem_cache *_crypt_io_pool;
140 static void clone_init(struct dm_crypt_io *, struct bio *);
141 static void kcryptd_queue_crypt(struct dm_crypt_io *io);
144 * Different IV generation algorithms:
146 * plain: the initial vector is the 32-bit little-endian version of the sector
147 * number, padded with zeros if necessary.
149 * essiv: "encrypted sector|salt initial vector", the sector number is
150 * encrypted with the bulk cipher using a salt as key. The salt
151 * should be derived from the bulk cipher's key via hashing.
153 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
154 * (needed for LRW-32-AES and possible other narrow block modes)
156 * null: the initial vector is always zero. Provides compatibility with
157 * obsolete loop_fish2 devices. Do not use for new devices.
159 * plumb: unimplemented, see:
160 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
163 static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
165 memset(iv, 0, cc->iv_size);
166 *(u32 *)iv = cpu_to_le32(sector & 0xffffffff);
171 static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
174 struct crypto_cipher *essiv_tfm;
175 struct crypto_hash *hash_tfm;
176 struct hash_desc desc;
177 struct scatterlist sg;
178 unsigned int saltsize;
183 ti->error = "Digest algorithm missing for ESSIV mode";
187 /* Hash the cipher key with the given hash algorithm */
188 hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
189 if (IS_ERR(hash_tfm)) {
190 ti->error = "Error initializing ESSIV hash";
191 return PTR_ERR(hash_tfm);
194 saltsize = crypto_hash_digestsize(hash_tfm);
195 salt = kmalloc(saltsize, GFP_KERNEL);
197 ti->error = "Error kmallocing salt storage in ESSIV";
198 crypto_free_hash(hash_tfm);
202 sg_init_one(&sg, cc->key, cc->key_size);
204 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
205 err = crypto_hash_digest(&desc, &sg, cc->key_size, salt);
206 crypto_free_hash(hash_tfm);
209 ti->error = "Error calculating hash in ESSIV";
214 /* Setup the essiv_tfm with the given salt */
215 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
216 if (IS_ERR(essiv_tfm)) {
217 ti->error = "Error allocating crypto tfm for ESSIV";
219 return PTR_ERR(essiv_tfm);
221 if (crypto_cipher_blocksize(essiv_tfm) !=
222 crypto_ablkcipher_ivsize(cc->tfm)) {
223 ti->error = "Block size of ESSIV cipher does "
224 "not match IV size of block cipher";
225 crypto_free_cipher(essiv_tfm);
229 err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
231 ti->error = "Failed to set key for ESSIV cipher";
232 crypto_free_cipher(essiv_tfm);
238 cc->iv_gen_private.essiv_tfm = essiv_tfm;
242 static void crypt_iv_essiv_dtr(struct crypt_config *cc)
244 crypto_free_cipher(cc->iv_gen_private.essiv_tfm);
245 cc->iv_gen_private.essiv_tfm = NULL;
248 static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
250 memset(iv, 0, cc->iv_size);
251 *(u64 *)iv = cpu_to_le64(sector);
252 crypto_cipher_encrypt_one(cc->iv_gen_private.essiv_tfm, iv, iv);
256 static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
259 unsigned bs = crypto_ablkcipher_blocksize(cc->tfm);
262 /* we need to calculate how far we must shift the sector count
263 * to get the cipher block count, we use this shift in _gen */
265 if (1 << log != bs) {
266 ti->error = "cypher blocksize is not a power of 2";
271 ti->error = "cypher blocksize is > 512";
275 cc->iv_gen_private.benbi_shift = 9 - log;
280 static void crypt_iv_benbi_dtr(struct crypt_config *cc)
284 static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
288 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
290 val = cpu_to_be64(((u64)sector << cc->iv_gen_private.benbi_shift) + 1);
291 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
296 static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
298 memset(iv, 0, cc->iv_size);
303 static struct crypt_iv_operations crypt_iv_plain_ops = {
304 .generator = crypt_iv_plain_gen
307 static struct crypt_iv_operations crypt_iv_essiv_ops = {
308 .ctr = crypt_iv_essiv_ctr,
309 .dtr = crypt_iv_essiv_dtr,
310 .generator = crypt_iv_essiv_gen
313 static struct crypt_iv_operations crypt_iv_benbi_ops = {
314 .ctr = crypt_iv_benbi_ctr,
315 .dtr = crypt_iv_benbi_dtr,
316 .generator = crypt_iv_benbi_gen
319 static struct crypt_iv_operations crypt_iv_null_ops = {
320 .generator = crypt_iv_null_gen
323 static void crypt_convert_init(struct crypt_config *cc,
324 struct convert_context *ctx,
325 struct bio *bio_out, struct bio *bio_in,
328 ctx->bio_in = bio_in;
329 ctx->bio_out = bio_out;
332 ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
333 ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
334 ctx->sector = sector + cc->iv_offset;
335 init_completion(&ctx->restart);
336 atomic_set(&ctx->pending, 1);
339 static int crypt_convert_block(struct crypt_config *cc,
340 struct convert_context *ctx,
341 struct ablkcipher_request *req)
343 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
344 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
345 struct dm_crypt_request *dmreq;
349 dmreq = (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
350 iv = (u8 *)ALIGN((unsigned long)(dmreq + 1),
351 crypto_ablkcipher_alignmask(cc->tfm) + 1);
353 sg_init_table(&dmreq->sg_in, 1);
354 sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
355 bv_in->bv_offset + ctx->offset_in);
357 sg_init_table(&dmreq->sg_out, 1);
358 sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
359 bv_out->bv_offset + ctx->offset_out);
361 ctx->offset_in += 1 << SECTOR_SHIFT;
362 if (ctx->offset_in >= bv_in->bv_len) {
367 ctx->offset_out += 1 << SECTOR_SHIFT;
368 if (ctx->offset_out >= bv_out->bv_len) {
373 if (cc->iv_gen_ops) {
374 r = cc->iv_gen_ops->generator(cc, iv, ctx->sector);
379 ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
380 1 << SECTOR_SHIFT, iv);
382 if (bio_data_dir(ctx->bio_in) == WRITE)
383 r = crypto_ablkcipher_encrypt(req);
385 r = crypto_ablkcipher_decrypt(req);
390 static void kcryptd_async_done(struct crypto_async_request *async_req,
392 static void crypt_alloc_req(struct crypt_config *cc,
393 struct convert_context *ctx)
396 cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
397 ablkcipher_request_set_tfm(cc->req, cc->tfm);
398 ablkcipher_request_set_callback(cc->req, CRYPTO_TFM_REQ_MAY_BACKLOG |
399 CRYPTO_TFM_REQ_MAY_SLEEP,
400 kcryptd_async_done, ctx);
404 * Encrypt / decrypt data from one bio to another one (can be the same one)
406 static int crypt_convert(struct crypt_config *cc,
407 struct convert_context *ctx)
411 while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
412 ctx->idx_out < ctx->bio_out->bi_vcnt) {
414 crypt_alloc_req(cc, ctx);
416 atomic_inc(&ctx->pending);
418 r = crypt_convert_block(cc, ctx, cc->req);
423 wait_for_completion(&ctx->restart);
424 INIT_COMPLETION(ctx->restart);
433 atomic_dec(&ctx->pending);
440 atomic_dec(&ctx->pending);
448 static void dm_crypt_bio_destructor(struct bio *bio)
450 struct dm_crypt_io *io = bio->bi_private;
451 struct crypt_config *cc = io->target->private;
453 bio_free(bio, cc->bs);
457 * Generate a new unfragmented bio with the given size
458 * This should never violate the device limitations
459 * May return a smaller bio when running out of pages
461 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
463 struct crypt_config *cc = io->target->private;
465 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
466 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
470 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
474 clone_init(io, clone);
476 for (i = 0; i < nr_iovecs; i++) {
477 page = mempool_alloc(cc->page_pool, gfp_mask);
482 * if additional pages cannot be allocated without waiting,
483 * return a partially allocated bio, the caller will then try
484 * to allocate additional bios while submitting this partial bio
486 if (i == (MIN_BIO_PAGES - 1))
487 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
489 len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
491 if (!bio_add_page(clone, page, len, 0)) {
492 mempool_free(page, cc->page_pool);
499 if (!clone->bi_size) {
507 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
512 for (i = 0; i < clone->bi_vcnt; i++) {
513 bv = bio_iovec_idx(clone, i);
514 BUG_ON(!bv->bv_page);
515 mempool_free(bv->bv_page, cc->page_pool);
520 static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti,
521 struct bio *bio, sector_t sector)
523 struct crypt_config *cc = ti->private;
524 struct dm_crypt_io *io;
526 io = mempool_alloc(cc->io_pool, GFP_NOIO);
531 atomic_set(&io->pending, 0);
536 static void crypt_inc_pending(struct dm_crypt_io *io)
538 atomic_inc(&io->pending);
542 * One of the bios was finished. Check for completion of
543 * the whole request and correctly clean up the buffer.
545 static void crypt_dec_pending(struct dm_crypt_io *io)
547 struct crypt_config *cc = io->target->private;
549 if (!atomic_dec_and_test(&io->pending))
552 bio_endio(io->base_bio, io->error);
553 mempool_free(io, cc->io_pool);
557 * kcryptd/kcryptd_io:
559 * Needed because it would be very unwise to do decryption in an
562 * kcryptd performs the actual encryption or decryption.
564 * kcryptd_io performs the IO submission.
566 * They must be separated as otherwise the final stages could be
567 * starved by new requests which can block in the first stages due
568 * to memory allocation.
570 static void crypt_endio(struct bio *clone, int error)
572 struct dm_crypt_io *io = clone->bi_private;
573 struct crypt_config *cc = io->target->private;
574 unsigned rw = bio_data_dir(clone);
576 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
580 * free the processed pages
583 crypt_free_buffer_pages(cc, clone);
587 if (rw == READ && !error) {
588 kcryptd_queue_crypt(io);
595 crypt_dec_pending(io);
598 static void clone_init(struct dm_crypt_io *io, struct bio *clone)
600 struct crypt_config *cc = io->target->private;
602 clone->bi_private = io;
603 clone->bi_end_io = crypt_endio;
604 clone->bi_bdev = cc->dev->bdev;
605 clone->bi_rw = io->base_bio->bi_rw;
606 clone->bi_destructor = dm_crypt_bio_destructor;
609 static void kcryptd_io_read(struct dm_crypt_io *io)
611 struct crypt_config *cc = io->target->private;
612 struct bio *base_bio = io->base_bio;
615 crypt_inc_pending(io);
618 * The block layer might modify the bvec array, so always
619 * copy the required bvecs because we need the original
620 * one in order to decrypt the whole bio data *afterwards*.
622 clone = bio_alloc_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs);
623 if (unlikely(!clone)) {
625 crypt_dec_pending(io);
629 clone_init(io, clone);
631 clone->bi_vcnt = bio_segments(base_bio);
632 clone->bi_size = base_bio->bi_size;
633 clone->bi_sector = cc->start + io->sector;
634 memcpy(clone->bi_io_vec, bio_iovec(base_bio),
635 sizeof(struct bio_vec) * clone->bi_vcnt);
637 generic_make_request(clone);
640 static void kcryptd_io_write(struct dm_crypt_io *io)
642 struct bio *clone = io->ctx.bio_out;
643 struct crypt_config *cc = io->target->private;
645 generic_make_request(clone);
646 wake_up(&cc->writeq);
649 static void kcryptd_io(struct work_struct *work)
651 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
653 if (bio_data_dir(io->base_bio) == READ)
656 kcryptd_io_write(io);
659 static void kcryptd_queue_io(struct dm_crypt_io *io)
661 struct crypt_config *cc = io->target->private;
663 INIT_WORK(&io->work, kcryptd_io);
664 queue_work(cc->io_queue, &io->work);
667 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
668 int error, int async)
670 struct bio *clone = io->ctx.bio_out;
671 struct crypt_config *cc = io->target->private;
673 if (unlikely(error < 0)) {
674 crypt_free_buffer_pages(cc, clone);
680 /* crypt_convert should have filled the clone bio */
681 BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
683 clone->bi_sector = cc->start + io->sector;
684 io->sector += bio_sectors(clone);
687 kcryptd_queue_io(io);
689 generic_make_request(clone);
692 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
694 struct crypt_config *cc = io->target->private;
696 unsigned remaining = io->base_bio->bi_size;
700 * Prevent io from disappearing until this function completes.
702 crypt_inc_pending(io);
703 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, io->sector);
706 * The allocated buffers can be smaller than the whole bio,
707 * so repeat the whole process until all the data can be handled.
710 clone = crypt_alloc_buffer(io, remaining);
711 if (unlikely(!clone)) {
716 io->ctx.bio_out = clone;
719 remaining -= clone->bi_size;
721 r = crypt_convert(cc, &io->ctx);
723 if (atomic_dec_and_test(&io->ctx.pending)) {
724 /* processed, no running async crypto */
725 crypt_inc_pending(io);
726 kcryptd_crypt_write_io_submit(io, r, 0);
727 if (unlikely(r < 0)) {
728 crypt_dec_pending(io);
732 crypt_inc_pending(io);
734 /* out of memory -> run queues */
735 if (unlikely(remaining)) {
736 /* wait for async crypto then reinitialize pending */
737 wait_event(cc->writeq, !atomic_read(&io->ctx.pending));
738 atomic_set(&io->ctx.pending, 1);
739 congestion_wait(WRITE, HZ/100);
743 crypt_dec_pending(io);
746 static void kcryptd_crypt_read_done(struct dm_crypt_io *io, int error)
748 if (unlikely(error < 0))
751 crypt_dec_pending(io);
754 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
756 struct crypt_config *cc = io->target->private;
759 crypt_inc_pending(io);
761 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
764 r = crypt_convert(cc, &io->ctx);
766 if (atomic_dec_and_test(&io->ctx.pending))
767 kcryptd_crypt_read_done(io, r);
769 crypt_dec_pending(io);
772 static void kcryptd_async_done(struct crypto_async_request *async_req,
775 struct convert_context *ctx = async_req->data;
776 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
777 struct crypt_config *cc = io->target->private;
779 if (error == -EINPROGRESS) {
780 complete(&ctx->restart);
784 mempool_free(ablkcipher_request_cast(async_req), cc->req_pool);
786 if (!atomic_dec_and_test(&ctx->pending))
789 if (bio_data_dir(io->base_bio) == READ)
790 kcryptd_crypt_read_done(io, error);
792 kcryptd_crypt_write_io_submit(io, error, 1);
795 static void kcryptd_crypt(struct work_struct *work)
797 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
799 if (bio_data_dir(io->base_bio) == READ)
800 kcryptd_crypt_read_convert(io);
802 kcryptd_crypt_write_convert(io);
805 static void kcryptd_queue_crypt(struct dm_crypt_io *io)
807 struct crypt_config *cc = io->target->private;
809 INIT_WORK(&io->work, kcryptd_crypt);
810 queue_work(cc->crypt_queue, &io->work);
814 * Decode key from its hex representation
816 static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
824 for (i = 0; i < size; i++) {
828 key[i] = (u8)simple_strtoul(buffer, &endp, 16);
830 if (endp != &buffer[2])
841 * Encode key into its hex representation
843 static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
847 for (i = 0; i < size; i++) {
848 sprintf(hex, "%02x", *key);
854 static int crypt_set_key(struct crypt_config *cc, char *key)
856 unsigned key_size = strlen(key) >> 1;
858 if (cc->key_size && cc->key_size != key_size)
861 cc->key_size = key_size; /* initial settings */
863 if ((!key_size && strcmp(key, "-")) ||
864 (key_size && crypt_decode_key(cc->key, key, key_size) < 0))
867 set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
872 static int crypt_wipe_key(struct crypt_config *cc)
874 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
875 memset(&cc->key, 0, cc->key_size * sizeof(u8));
880 * Construct an encryption mapping:
881 * <cipher> <key> <iv_offset> <dev_path> <start>
883 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
885 struct crypt_config *cc;
886 struct crypto_ablkcipher *tfm;
892 unsigned int key_size;
893 unsigned long long tmpll;
896 ti->error = "Not enough arguments";
901 cipher = strsep(&tmp, "-");
902 chainmode = strsep(&tmp, "-");
903 ivopts = strsep(&tmp, "-");
904 ivmode = strsep(&ivopts, ":");
907 DMWARN("Unexpected additional cipher options");
909 key_size = strlen(argv[1]) >> 1;
911 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
914 "Cannot allocate transparent encryption context";
918 if (crypt_set_key(cc, argv[1])) {
919 ti->error = "Error decoding key";
923 /* Compatiblity mode for old dm-crypt cipher strings */
924 if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
929 if (strcmp(chainmode, "ecb") && !ivmode) {
930 ti->error = "This chaining mode requires an IV mechanism";
934 if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)",
935 chainmode, cipher) >= CRYPTO_MAX_ALG_NAME) {
936 ti->error = "Chain mode + cipher name is too long";
940 tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
942 ti->error = "Error allocating crypto tfm";
946 strcpy(cc->cipher, cipher);
947 strcpy(cc->chainmode, chainmode);
951 * Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi".
952 * See comments at iv code
956 cc->iv_gen_ops = NULL;
957 else if (strcmp(ivmode, "plain") == 0)
958 cc->iv_gen_ops = &crypt_iv_plain_ops;
959 else if (strcmp(ivmode, "essiv") == 0)
960 cc->iv_gen_ops = &crypt_iv_essiv_ops;
961 else if (strcmp(ivmode, "benbi") == 0)
962 cc->iv_gen_ops = &crypt_iv_benbi_ops;
963 else if (strcmp(ivmode, "null") == 0)
964 cc->iv_gen_ops = &crypt_iv_null_ops;
966 ti->error = "Invalid IV mode";
970 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr &&
971 cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
974 cc->iv_size = crypto_ablkcipher_ivsize(tfm);
976 /* at least a 64 bit sector number should fit in our buffer */
977 cc->iv_size = max(cc->iv_size,
978 (unsigned int)(sizeof(u64) / sizeof(u8)));
980 if (cc->iv_gen_ops) {
981 DMWARN("Selected cipher does not support IVs");
982 if (cc->iv_gen_ops->dtr)
983 cc->iv_gen_ops->dtr(cc);
984 cc->iv_gen_ops = NULL;
988 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
990 ti->error = "Cannot allocate crypt io mempool";
994 cc->dmreq_start = sizeof(struct ablkcipher_request);
995 cc->dmreq_start += crypto_ablkcipher_reqsize(tfm);
996 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
997 cc->dmreq_start += crypto_ablkcipher_alignmask(tfm) &
998 ~(crypto_tfm_ctx_alignment() - 1);
1000 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1001 sizeof(struct dm_crypt_request) + cc->iv_size);
1002 if (!cc->req_pool) {
1003 ti->error = "Cannot allocate crypt request mempool";
1008 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1009 if (!cc->page_pool) {
1010 ti->error = "Cannot allocate page mempool";
1014 cc->bs = bioset_create(MIN_IOS, MIN_IOS);
1016 ti->error = "Cannot allocate crypt bioset";
1020 if (crypto_ablkcipher_setkey(tfm, cc->key, key_size) < 0) {
1021 ti->error = "Error setting key";
1025 if (sscanf(argv[2], "%llu", &tmpll) != 1) {
1026 ti->error = "Invalid iv_offset sector";
1029 cc->iv_offset = tmpll;
1031 if (sscanf(argv[4], "%llu", &tmpll) != 1) {
1032 ti->error = "Invalid device sector";
1037 if (dm_get_device(ti, argv[3], cc->start, ti->len,
1038 dm_table_get_mode(ti->table), &cc->dev)) {
1039 ti->error = "Device lookup failed";
1043 if (ivmode && cc->iv_gen_ops) {
1045 *(ivopts - 1) = ':';
1046 cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL);
1048 ti->error = "Error kmallocing iv_mode string";
1049 goto bad_ivmode_string;
1051 strcpy(cc->iv_mode, ivmode);
1055 cc->io_queue = create_singlethread_workqueue("kcryptd_io");
1056 if (!cc->io_queue) {
1057 ti->error = "Couldn't create kcryptd io queue";
1061 cc->crypt_queue = create_singlethread_workqueue("kcryptd");
1062 if (!cc->crypt_queue) {
1063 ti->error = "Couldn't create kcryptd queue";
1064 goto bad_crypt_queue;
1067 init_waitqueue_head(&cc->writeq);
1072 destroy_workqueue(cc->io_queue);
1076 dm_put_device(ti, cc->dev);
1078 bioset_free(cc->bs);
1080 mempool_destroy(cc->page_pool);
1082 mempool_destroy(cc->req_pool);
1084 mempool_destroy(cc->io_pool);
1086 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1087 cc->iv_gen_ops->dtr(cc);
1089 crypto_free_ablkcipher(tfm);
1091 /* Must zero key material before freeing */
1092 memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
1097 static void crypt_dtr(struct dm_target *ti)
1099 struct crypt_config *cc = (struct crypt_config *) ti->private;
1101 destroy_workqueue(cc->io_queue);
1102 destroy_workqueue(cc->crypt_queue);
1105 mempool_free(cc->req, cc->req_pool);
1107 bioset_free(cc->bs);
1108 mempool_destroy(cc->page_pool);
1109 mempool_destroy(cc->req_pool);
1110 mempool_destroy(cc->io_pool);
1113 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1114 cc->iv_gen_ops->dtr(cc);
1115 crypto_free_ablkcipher(cc->tfm);
1116 dm_put_device(ti, cc->dev);
1118 /* Must zero key material before freeing */
1119 memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
1123 static int crypt_map(struct dm_target *ti, struct bio *bio,
1124 union map_info *map_context)
1126 struct dm_crypt_io *io;
1128 io = crypt_io_alloc(ti, bio, bio->bi_sector - ti->begin);
1130 if (bio_data_dir(io->base_bio) == READ)
1131 kcryptd_queue_io(io);
1133 kcryptd_queue_crypt(io);
1135 return DM_MAPIO_SUBMITTED;
1138 static int crypt_status(struct dm_target *ti, status_type_t type,
1139 char *result, unsigned int maxlen)
1141 struct crypt_config *cc = (struct crypt_config *) ti->private;
1142 unsigned int sz = 0;
1145 case STATUSTYPE_INFO:
1149 case STATUSTYPE_TABLE:
1151 DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode,
1154 DMEMIT("%s-%s ", cc->cipher, cc->chainmode);
1156 if (cc->key_size > 0) {
1157 if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1160 crypt_encode_key(result + sz, cc->key, cc->key_size);
1161 sz += cc->key_size << 1;
1168 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1169 cc->dev->name, (unsigned long long)cc->start);
1175 static void crypt_postsuspend(struct dm_target *ti)
1177 struct crypt_config *cc = ti->private;
1179 set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1182 static int crypt_preresume(struct dm_target *ti)
1184 struct crypt_config *cc = ti->private;
1186 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1187 DMERR("aborting resume - crypt key is not set.");
1194 static void crypt_resume(struct dm_target *ti)
1196 struct crypt_config *cc = ti->private;
1198 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1201 /* Message interface
1205 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1207 struct crypt_config *cc = ti->private;
1212 if (!strnicmp(argv[0], MESG_STR("key"))) {
1213 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1214 DMWARN("not suspended during key manipulation.");
1217 if (argc == 3 && !strnicmp(argv[1], MESG_STR("set")))
1218 return crypt_set_key(cc, argv[2]);
1219 if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe")))
1220 return crypt_wipe_key(cc);
1224 DMWARN("unrecognised message received.");
1228 static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1229 struct bio_vec *biovec, int max_size)
1231 struct crypt_config *cc = ti->private;
1232 struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1234 if (!q->merge_bvec_fn)
1237 bvm->bi_bdev = cc->dev->bdev;
1238 bvm->bi_sector = cc->start + bvm->bi_sector - ti->begin;
1240 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1243 static struct target_type crypt_target = {
1245 .version= {1, 6, 0},
1246 .module = THIS_MODULE,
1250 .status = crypt_status,
1251 .postsuspend = crypt_postsuspend,
1252 .preresume = crypt_preresume,
1253 .resume = crypt_resume,
1254 .message = crypt_message,
1255 .merge = crypt_merge,
1258 static int __init dm_crypt_init(void)
1262 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1263 if (!_crypt_io_pool)
1266 r = dm_register_target(&crypt_target);
1268 DMERR("register failed %d", r);
1269 kmem_cache_destroy(_crypt_io_pool);
1275 static void __exit dm_crypt_exit(void)
1277 int r = dm_unregister_target(&crypt_target);
1280 DMERR("unregister failed %d", r);
1282 kmem_cache_destroy(_crypt_io_pool);
1285 module_init(dm_crypt_init);
1286 module_exit(dm_crypt_exit);
1288 MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1289 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1290 MODULE_LICENSE("GPL");