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);
338 static int crypt_convert_block(struct crypt_config *cc,
339 struct convert_context *ctx,
340 struct ablkcipher_request *req)
342 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
343 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
344 struct dm_crypt_request *dmreq;
348 dmreq = (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
349 iv = (u8 *)ALIGN((unsigned long)(dmreq + 1),
350 crypto_ablkcipher_alignmask(cc->tfm) + 1);
352 sg_init_table(&dmreq->sg_in, 1);
353 sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
354 bv_in->bv_offset + ctx->offset_in);
356 sg_init_table(&dmreq->sg_out, 1);
357 sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
358 bv_out->bv_offset + ctx->offset_out);
360 ctx->offset_in += 1 << SECTOR_SHIFT;
361 if (ctx->offset_in >= bv_in->bv_len) {
366 ctx->offset_out += 1 << SECTOR_SHIFT;
367 if (ctx->offset_out >= bv_out->bv_len) {
372 if (cc->iv_gen_ops) {
373 r = cc->iv_gen_ops->generator(cc, iv, ctx->sector);
378 ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
379 1 << SECTOR_SHIFT, iv);
381 if (bio_data_dir(ctx->bio_in) == WRITE)
382 r = crypto_ablkcipher_encrypt(req);
384 r = crypto_ablkcipher_decrypt(req);
389 static void kcryptd_async_done(struct crypto_async_request *async_req,
391 static void crypt_alloc_req(struct crypt_config *cc,
392 struct convert_context *ctx)
395 cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
396 ablkcipher_request_set_tfm(cc->req, cc->tfm);
397 ablkcipher_request_set_callback(cc->req, CRYPTO_TFM_REQ_MAY_BACKLOG |
398 CRYPTO_TFM_REQ_MAY_SLEEP,
399 kcryptd_async_done, ctx);
403 * Encrypt / decrypt data from one bio to another one (can be the same one)
405 static int crypt_convert(struct crypt_config *cc,
406 struct convert_context *ctx)
410 atomic_set(&ctx->pending, 1);
412 while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
413 ctx->idx_out < ctx->bio_out->bi_vcnt) {
415 crypt_alloc_req(cc, ctx);
417 atomic_inc(&ctx->pending);
419 r = crypt_convert_block(cc, ctx, cc->req);
424 wait_for_completion(&ctx->restart);
425 INIT_COMPLETION(ctx->restart);
434 atomic_dec(&ctx->pending);
441 atomic_dec(&ctx->pending);
449 static void dm_crypt_bio_destructor(struct bio *bio)
451 struct dm_crypt_io *io = bio->bi_private;
452 struct crypt_config *cc = io->target->private;
454 bio_free(bio, cc->bs);
458 * Generate a new unfragmented bio with the given size
459 * This should never violate the device limitations
460 * May return a smaller bio when running out of pages
462 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
464 struct crypt_config *cc = io->target->private;
466 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
467 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
471 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
475 clone_init(io, clone);
477 for (i = 0; i < nr_iovecs; i++) {
478 page = mempool_alloc(cc->page_pool, gfp_mask);
483 * if additional pages cannot be allocated without waiting,
484 * return a partially allocated bio, the caller will then try
485 * to allocate additional bios while submitting this partial bio
487 if (i == (MIN_BIO_PAGES - 1))
488 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
490 len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
492 if (!bio_add_page(clone, page, len, 0)) {
493 mempool_free(page, cc->page_pool);
500 if (!clone->bi_size) {
508 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
513 for (i = 0; i < clone->bi_vcnt; i++) {
514 bv = bio_iovec_idx(clone, i);
515 BUG_ON(!bv->bv_page);
516 mempool_free(bv->bv_page, cc->page_pool);
521 static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti,
522 struct bio *bio, sector_t sector)
524 struct crypt_config *cc = ti->private;
525 struct dm_crypt_io *io;
527 io = mempool_alloc(cc->io_pool, GFP_NOIO);
532 atomic_set(&io->pending, 0);
537 static void crypt_inc_pending(struct dm_crypt_io *io)
539 atomic_inc(&io->pending);
543 * One of the bios was finished. Check for completion of
544 * the whole request and correctly clean up the buffer.
546 static void crypt_dec_pending(struct dm_crypt_io *io)
548 struct crypt_config *cc = io->target->private;
550 if (!atomic_dec_and_test(&io->pending))
553 bio_endio(io->base_bio, io->error);
554 mempool_free(io, cc->io_pool);
558 * kcryptd/kcryptd_io:
560 * Needed because it would be very unwise to do decryption in an
563 * kcryptd performs the actual encryption or decryption.
565 * kcryptd_io performs the IO submission.
567 * They must be separated as otherwise the final stages could be
568 * starved by new requests which can block in the first stages due
569 * to memory allocation.
571 static void crypt_endio(struct bio *clone, int error)
573 struct dm_crypt_io *io = clone->bi_private;
574 struct crypt_config *cc = io->target->private;
575 unsigned rw = bio_data_dir(clone);
577 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
581 * free the processed pages
584 crypt_free_buffer_pages(cc, clone);
588 if (rw == READ && !error) {
589 kcryptd_queue_crypt(io);
596 crypt_dec_pending(io);
599 static void clone_init(struct dm_crypt_io *io, struct bio *clone)
601 struct crypt_config *cc = io->target->private;
603 clone->bi_private = io;
604 clone->bi_end_io = crypt_endio;
605 clone->bi_bdev = cc->dev->bdev;
606 clone->bi_rw = io->base_bio->bi_rw;
607 clone->bi_destructor = dm_crypt_bio_destructor;
610 static void kcryptd_io_read(struct dm_crypt_io *io)
612 struct crypt_config *cc = io->target->private;
613 struct bio *base_bio = io->base_bio;
616 crypt_inc_pending(io);
619 * The block layer might modify the bvec array, so always
620 * copy the required bvecs because we need the original
621 * one in order to decrypt the whole bio data *afterwards*.
623 clone = bio_alloc_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs);
624 if (unlikely(!clone)) {
626 crypt_dec_pending(io);
630 clone_init(io, clone);
632 clone->bi_vcnt = bio_segments(base_bio);
633 clone->bi_size = base_bio->bi_size;
634 clone->bi_sector = cc->start + io->sector;
635 memcpy(clone->bi_io_vec, bio_iovec(base_bio),
636 sizeof(struct bio_vec) * clone->bi_vcnt);
638 generic_make_request(clone);
641 static void kcryptd_io_write(struct dm_crypt_io *io)
643 struct bio *clone = io->ctx.bio_out;
644 struct crypt_config *cc = io->target->private;
646 generic_make_request(clone);
647 wake_up(&cc->writeq);
650 static void kcryptd_io(struct work_struct *work)
652 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
654 if (bio_data_dir(io->base_bio) == READ)
657 kcryptd_io_write(io);
660 static void kcryptd_queue_io(struct dm_crypt_io *io)
662 struct crypt_config *cc = io->target->private;
664 INIT_WORK(&io->work, kcryptd_io);
665 queue_work(cc->io_queue, &io->work);
668 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
669 int error, int async)
671 struct bio *clone = io->ctx.bio_out;
672 struct crypt_config *cc = io->target->private;
674 if (unlikely(error < 0)) {
675 crypt_free_buffer_pages(cc, clone);
678 crypt_dec_pending(io);
682 /* crypt_convert should have filled the clone bio */
683 BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
685 clone->bi_sector = cc->start + io->sector;
686 io->sector += bio_sectors(clone);
689 kcryptd_queue_io(io);
691 generic_make_request(clone);
694 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
696 struct crypt_config *cc = io->target->private;
699 unsigned remaining = io->base_bio->bi_size;
703 * Prevent io from disappearing until this function completes.
705 crypt_inc_pending(io);
706 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, io->sector);
709 * The allocated buffers can be smaller than the whole bio,
710 * so repeat the whole process until all the data can be handled.
713 clone = crypt_alloc_buffer(io, remaining);
714 if (unlikely(!clone)) {
719 io->ctx.bio_out = clone;
722 remaining -= clone->bi_size;
724 crypt_inc_pending(io);
725 r = crypt_convert(cc, &io->ctx);
726 crypt_finished = atomic_dec_and_test(&io->ctx.pending);
728 /* Encryption was already finished, submit io now */
729 if (crypt_finished) {
730 kcryptd_crypt_write_io_submit(io, r, 0);
733 * If there was an error, do not try next fragments.
734 * For async, error is processed in async handler.
740 /* out of memory -> run queues */
741 if (unlikely(remaining)) {
742 wait_event(cc->writeq, !atomic_read(&io->ctx.pending));
743 congestion_wait(WRITE, HZ/100);
747 crypt_dec_pending(io);
750 static void kcryptd_crypt_read_done(struct dm_crypt_io *io, int error)
752 if (unlikely(error < 0))
755 crypt_dec_pending(io);
758 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
760 struct crypt_config *cc = io->target->private;
763 crypt_inc_pending(io);
765 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
768 r = crypt_convert(cc, &io->ctx);
770 if (atomic_dec_and_test(&io->ctx.pending))
771 kcryptd_crypt_read_done(io, r);
773 crypt_dec_pending(io);
776 static void kcryptd_async_done(struct crypto_async_request *async_req,
779 struct convert_context *ctx = async_req->data;
780 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
781 struct crypt_config *cc = io->target->private;
783 if (error == -EINPROGRESS) {
784 complete(&ctx->restart);
788 mempool_free(ablkcipher_request_cast(async_req), cc->req_pool);
790 if (!atomic_dec_and_test(&ctx->pending))
793 if (bio_data_dir(io->base_bio) == READ)
794 kcryptd_crypt_read_done(io, error);
796 kcryptd_crypt_write_io_submit(io, error, 1);
799 static void kcryptd_crypt(struct work_struct *work)
801 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
803 if (bio_data_dir(io->base_bio) == READ)
804 kcryptd_crypt_read_convert(io);
806 kcryptd_crypt_write_convert(io);
809 static void kcryptd_queue_crypt(struct dm_crypt_io *io)
811 struct crypt_config *cc = io->target->private;
813 INIT_WORK(&io->work, kcryptd_crypt);
814 queue_work(cc->crypt_queue, &io->work);
818 * Decode key from its hex representation
820 static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
828 for (i = 0; i < size; i++) {
832 key[i] = (u8)simple_strtoul(buffer, &endp, 16);
834 if (endp != &buffer[2])
845 * Encode key into its hex representation
847 static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
851 for (i = 0; i < size; i++) {
852 sprintf(hex, "%02x", *key);
858 static int crypt_set_key(struct crypt_config *cc, char *key)
860 unsigned key_size = strlen(key) >> 1;
862 if (cc->key_size && cc->key_size != key_size)
865 cc->key_size = key_size; /* initial settings */
867 if ((!key_size && strcmp(key, "-")) ||
868 (key_size && crypt_decode_key(cc->key, key, key_size) < 0))
871 set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
876 static int crypt_wipe_key(struct crypt_config *cc)
878 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
879 memset(&cc->key, 0, cc->key_size * sizeof(u8));
884 * Construct an encryption mapping:
885 * <cipher> <key> <iv_offset> <dev_path> <start>
887 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
889 struct crypt_config *cc;
890 struct crypto_ablkcipher *tfm;
896 unsigned int key_size;
897 unsigned long long tmpll;
900 ti->error = "Not enough arguments";
905 cipher = strsep(&tmp, "-");
906 chainmode = strsep(&tmp, "-");
907 ivopts = strsep(&tmp, "-");
908 ivmode = strsep(&ivopts, ":");
911 DMWARN("Unexpected additional cipher options");
913 key_size = strlen(argv[1]) >> 1;
915 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
918 "Cannot allocate transparent encryption context";
922 if (crypt_set_key(cc, argv[1])) {
923 ti->error = "Error decoding key";
927 /* Compatiblity mode for old dm-crypt cipher strings */
928 if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
933 if (strcmp(chainmode, "ecb") && !ivmode) {
934 ti->error = "This chaining mode requires an IV mechanism";
938 if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)",
939 chainmode, cipher) >= CRYPTO_MAX_ALG_NAME) {
940 ti->error = "Chain mode + cipher name is too long";
944 tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
946 ti->error = "Error allocating crypto tfm";
950 strcpy(cc->cipher, cipher);
951 strcpy(cc->chainmode, chainmode);
955 * Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi".
956 * See comments at iv code
960 cc->iv_gen_ops = NULL;
961 else if (strcmp(ivmode, "plain") == 0)
962 cc->iv_gen_ops = &crypt_iv_plain_ops;
963 else if (strcmp(ivmode, "essiv") == 0)
964 cc->iv_gen_ops = &crypt_iv_essiv_ops;
965 else if (strcmp(ivmode, "benbi") == 0)
966 cc->iv_gen_ops = &crypt_iv_benbi_ops;
967 else if (strcmp(ivmode, "null") == 0)
968 cc->iv_gen_ops = &crypt_iv_null_ops;
970 ti->error = "Invalid IV mode";
974 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr &&
975 cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
978 cc->iv_size = crypto_ablkcipher_ivsize(tfm);
980 /* at least a 64 bit sector number should fit in our buffer */
981 cc->iv_size = max(cc->iv_size,
982 (unsigned int)(sizeof(u64) / sizeof(u8)));
984 if (cc->iv_gen_ops) {
985 DMWARN("Selected cipher does not support IVs");
986 if (cc->iv_gen_ops->dtr)
987 cc->iv_gen_ops->dtr(cc);
988 cc->iv_gen_ops = NULL;
992 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
994 ti->error = "Cannot allocate crypt io mempool";
998 cc->dmreq_start = sizeof(struct ablkcipher_request);
999 cc->dmreq_start += crypto_ablkcipher_reqsize(tfm);
1000 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
1001 cc->dmreq_start += crypto_ablkcipher_alignmask(tfm) &
1002 ~(crypto_tfm_ctx_alignment() - 1);
1004 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1005 sizeof(struct dm_crypt_request) + cc->iv_size);
1006 if (!cc->req_pool) {
1007 ti->error = "Cannot allocate crypt request mempool";
1012 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1013 if (!cc->page_pool) {
1014 ti->error = "Cannot allocate page mempool";
1018 cc->bs = bioset_create(MIN_IOS, MIN_IOS);
1020 ti->error = "Cannot allocate crypt bioset";
1024 if (crypto_ablkcipher_setkey(tfm, cc->key, key_size) < 0) {
1025 ti->error = "Error setting key";
1029 if (sscanf(argv[2], "%llu", &tmpll) != 1) {
1030 ti->error = "Invalid iv_offset sector";
1033 cc->iv_offset = tmpll;
1035 if (sscanf(argv[4], "%llu", &tmpll) != 1) {
1036 ti->error = "Invalid device sector";
1041 if (dm_get_device(ti, argv[3], cc->start, ti->len,
1042 dm_table_get_mode(ti->table), &cc->dev)) {
1043 ti->error = "Device lookup failed";
1047 if (ivmode && cc->iv_gen_ops) {
1049 *(ivopts - 1) = ':';
1050 cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL);
1052 ti->error = "Error kmallocing iv_mode string";
1053 goto bad_ivmode_string;
1055 strcpy(cc->iv_mode, ivmode);
1059 cc->io_queue = create_singlethread_workqueue("kcryptd_io");
1060 if (!cc->io_queue) {
1061 ti->error = "Couldn't create kcryptd io queue";
1065 cc->crypt_queue = create_singlethread_workqueue("kcryptd");
1066 if (!cc->crypt_queue) {
1067 ti->error = "Couldn't create kcryptd queue";
1068 goto bad_crypt_queue;
1071 init_waitqueue_head(&cc->writeq);
1076 destroy_workqueue(cc->io_queue);
1080 dm_put_device(ti, cc->dev);
1082 bioset_free(cc->bs);
1084 mempool_destroy(cc->page_pool);
1086 mempool_destroy(cc->req_pool);
1088 mempool_destroy(cc->io_pool);
1090 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1091 cc->iv_gen_ops->dtr(cc);
1093 crypto_free_ablkcipher(tfm);
1095 /* Must zero key material before freeing */
1096 memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
1101 static void crypt_dtr(struct dm_target *ti)
1103 struct crypt_config *cc = (struct crypt_config *) ti->private;
1105 destroy_workqueue(cc->io_queue);
1106 destroy_workqueue(cc->crypt_queue);
1109 mempool_free(cc->req, cc->req_pool);
1111 bioset_free(cc->bs);
1112 mempool_destroy(cc->page_pool);
1113 mempool_destroy(cc->req_pool);
1114 mempool_destroy(cc->io_pool);
1117 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1118 cc->iv_gen_ops->dtr(cc);
1119 crypto_free_ablkcipher(cc->tfm);
1120 dm_put_device(ti, cc->dev);
1122 /* Must zero key material before freeing */
1123 memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
1127 static int crypt_map(struct dm_target *ti, struct bio *bio,
1128 union map_info *map_context)
1130 struct dm_crypt_io *io;
1132 io = crypt_io_alloc(ti, bio, bio->bi_sector - ti->begin);
1134 if (bio_data_dir(io->base_bio) == READ)
1135 kcryptd_queue_io(io);
1137 kcryptd_queue_crypt(io);
1139 return DM_MAPIO_SUBMITTED;
1142 static int crypt_status(struct dm_target *ti, status_type_t type,
1143 char *result, unsigned int maxlen)
1145 struct crypt_config *cc = (struct crypt_config *) ti->private;
1146 unsigned int sz = 0;
1149 case STATUSTYPE_INFO:
1153 case STATUSTYPE_TABLE:
1155 DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode,
1158 DMEMIT("%s-%s ", cc->cipher, cc->chainmode);
1160 if (cc->key_size > 0) {
1161 if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1164 crypt_encode_key(result + sz, cc->key, cc->key_size);
1165 sz += cc->key_size << 1;
1172 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1173 cc->dev->name, (unsigned long long)cc->start);
1179 static void crypt_postsuspend(struct dm_target *ti)
1181 struct crypt_config *cc = ti->private;
1183 set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1186 static int crypt_preresume(struct dm_target *ti)
1188 struct crypt_config *cc = ti->private;
1190 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1191 DMERR("aborting resume - crypt key is not set.");
1198 static void crypt_resume(struct dm_target *ti)
1200 struct crypt_config *cc = ti->private;
1202 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1205 /* Message interface
1209 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1211 struct crypt_config *cc = ti->private;
1216 if (!strnicmp(argv[0], MESG_STR("key"))) {
1217 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1218 DMWARN("not suspended during key manipulation.");
1221 if (argc == 3 && !strnicmp(argv[1], MESG_STR("set")))
1222 return crypt_set_key(cc, argv[2]);
1223 if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe")))
1224 return crypt_wipe_key(cc);
1228 DMWARN("unrecognised message received.");
1232 static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1233 struct bio_vec *biovec, int max_size)
1235 struct crypt_config *cc = ti->private;
1236 struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1238 if (!q->merge_bvec_fn)
1241 bvm->bi_bdev = cc->dev->bdev;
1242 bvm->bi_sector = cc->start + bvm->bi_sector - ti->begin;
1244 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1247 static struct target_type crypt_target = {
1249 .version= {1, 6, 0},
1250 .module = THIS_MODULE,
1254 .status = crypt_status,
1255 .postsuspend = crypt_postsuspend,
1256 .preresume = crypt_preresume,
1257 .resume = crypt_resume,
1258 .message = crypt_message,
1259 .merge = crypt_merge,
1262 static int __init dm_crypt_init(void)
1266 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1267 if (!_crypt_io_pool)
1270 r = dm_register_target(&crypt_target);
1272 DMERR("register failed %d", r);
1273 kmem_cache_destroy(_crypt_io_pool);
1279 static void __exit dm_crypt_exit(void)
1281 int r = dm_unregister_target(&crypt_target);
1284 DMERR("unregister failed %d", r);
1286 kmem_cache_destroy(_crypt_io_pool);
1289 module_init(dm_crypt_init);
1290 module_exit(dm_crypt_exit);
1292 MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1293 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1294 MODULE_LICENSE("GPL");