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>
26 #include <linux/device-mapper.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;
59 struct dm_crypt_io *base_io;
62 struct dm_crypt_request {
63 struct convert_context *ctx;
64 struct scatterlist sg_in;
65 struct scatterlist sg_out;
70 struct crypt_iv_operations {
71 int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
73 void (*dtr)(struct crypt_config *cc);
74 int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
77 struct iv_essiv_private {
78 struct crypto_cipher *tfm;
81 struct iv_benbi_private {
86 * Crypt: maps a linear range of a block device
87 * and encrypts / decrypts at the same time.
89 enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
95 * pool for per bio private data, crypto requests and
96 * encryption requeusts/buffer pages
100 mempool_t *page_pool;
103 struct workqueue_struct *io_queue;
104 struct workqueue_struct *crypt_queue;
107 * crypto related data
109 struct crypt_iv_operations *iv_gen_ops;
112 struct iv_essiv_private essiv;
113 struct iv_benbi_private benbi;
116 unsigned int iv_size;
119 * Layout of each crypto request:
121 * struct ablkcipher_request
124 * struct dm_crypt_request
128 * The padding is added so that dm_crypt_request and the IV are
131 unsigned int dmreq_start;
132 struct ablkcipher_request *req;
134 char cipher[CRYPTO_MAX_ALG_NAME];
135 char chainmode[CRYPTO_MAX_ALG_NAME];
136 struct crypto_ablkcipher *tfm;
138 unsigned int key_size;
143 #define MIN_POOL_PAGES 32
144 #define MIN_BIO_PAGES 8
146 static struct kmem_cache *_crypt_io_pool;
148 static void clone_init(struct dm_crypt_io *, struct bio *);
149 static void kcryptd_queue_crypt(struct dm_crypt_io *io);
152 * Different IV generation algorithms:
154 * plain: the initial vector is the 32-bit little-endian version of the sector
155 * number, padded with zeros if necessary.
157 * essiv: "encrypted sector|salt initial vector", the sector number is
158 * encrypted with the bulk cipher using a salt as key. The salt
159 * should be derived from the bulk cipher's key via hashing.
161 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
162 * (needed for LRW-32-AES and possible other narrow block modes)
164 * null: the initial vector is always zero. Provides compatibility with
165 * obsolete loop_fish2 devices. Do not use for new devices.
167 * plumb: unimplemented, see:
168 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
171 static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
173 memset(iv, 0, cc->iv_size);
174 *(u32 *)iv = cpu_to_le32(sector & 0xffffffff);
179 static void crypt_iv_essiv_dtr(struct crypt_config *cc)
181 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
183 crypto_free_cipher(essiv->tfm);
187 static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
190 struct crypto_cipher *essiv_tfm;
191 struct crypto_hash *hash_tfm;
192 struct hash_desc desc;
193 struct scatterlist sg;
194 unsigned int saltsize;
199 ti->error = "Digest algorithm missing for ESSIV mode";
203 /* Hash the cipher key with the given hash algorithm */
204 hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
205 if (IS_ERR(hash_tfm)) {
206 ti->error = "Error initializing ESSIV hash";
207 return PTR_ERR(hash_tfm);
210 saltsize = crypto_hash_digestsize(hash_tfm);
211 salt = kmalloc(saltsize, GFP_KERNEL);
213 ti->error = "Error kmallocing salt storage in ESSIV";
214 crypto_free_hash(hash_tfm);
218 sg_init_one(&sg, cc->key, cc->key_size);
220 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
221 err = crypto_hash_digest(&desc, &sg, cc->key_size, salt);
222 crypto_free_hash(hash_tfm);
225 ti->error = "Error calculating hash in ESSIV";
230 /* Setup the essiv_tfm with the given salt */
231 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
232 if (IS_ERR(essiv_tfm)) {
233 ti->error = "Error allocating crypto tfm for ESSIV";
235 return PTR_ERR(essiv_tfm);
237 if (crypto_cipher_blocksize(essiv_tfm) !=
238 crypto_ablkcipher_ivsize(cc->tfm)) {
239 ti->error = "Block size of ESSIV cipher does "
240 "not match IV size of block cipher";
241 crypto_free_cipher(essiv_tfm);
245 err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
247 ti->error = "Failed to set key for ESSIV cipher";
248 crypto_free_cipher(essiv_tfm);
254 cc->iv_gen_private.essiv.tfm = essiv_tfm;
258 static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
260 memset(iv, 0, cc->iv_size);
261 *(u64 *)iv = cpu_to_le64(sector);
262 crypto_cipher_encrypt_one(cc->iv_gen_private.essiv.tfm, iv, iv);
266 static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
269 unsigned bs = crypto_ablkcipher_blocksize(cc->tfm);
272 /* we need to calculate how far we must shift the sector count
273 * to get the cipher block count, we use this shift in _gen */
275 if (1 << log != bs) {
276 ti->error = "cypher blocksize is not a power of 2";
281 ti->error = "cypher blocksize is > 512";
285 cc->iv_gen_private.benbi.shift = 9 - log;
290 static void crypt_iv_benbi_dtr(struct crypt_config *cc)
294 static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
298 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
300 val = cpu_to_be64(((u64)sector << cc->iv_gen_private.benbi.shift) + 1);
301 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
306 static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
308 memset(iv, 0, cc->iv_size);
313 static struct crypt_iv_operations crypt_iv_plain_ops = {
314 .generator = crypt_iv_plain_gen
317 static struct crypt_iv_operations crypt_iv_essiv_ops = {
318 .ctr = crypt_iv_essiv_ctr,
319 .dtr = crypt_iv_essiv_dtr,
320 .generator = crypt_iv_essiv_gen
323 static struct crypt_iv_operations crypt_iv_benbi_ops = {
324 .ctr = crypt_iv_benbi_ctr,
325 .dtr = crypt_iv_benbi_dtr,
326 .generator = crypt_iv_benbi_gen
329 static struct crypt_iv_operations crypt_iv_null_ops = {
330 .generator = crypt_iv_null_gen
333 static void crypt_convert_init(struct crypt_config *cc,
334 struct convert_context *ctx,
335 struct bio *bio_out, struct bio *bio_in,
338 ctx->bio_in = bio_in;
339 ctx->bio_out = bio_out;
342 ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
343 ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
344 ctx->sector = sector + cc->iv_offset;
345 init_completion(&ctx->restart);
348 static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
349 struct ablkcipher_request *req)
351 return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
354 static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc,
355 struct dm_crypt_request *dmreq)
357 return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start);
360 static int crypt_convert_block(struct crypt_config *cc,
361 struct convert_context *ctx,
362 struct ablkcipher_request *req)
364 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
365 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
366 struct dm_crypt_request *dmreq;
370 dmreq = dmreq_of_req(cc, req);
371 iv = (u8 *)ALIGN((unsigned long)(dmreq + 1),
372 crypto_ablkcipher_alignmask(cc->tfm) + 1);
375 sg_init_table(&dmreq->sg_in, 1);
376 sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
377 bv_in->bv_offset + ctx->offset_in);
379 sg_init_table(&dmreq->sg_out, 1);
380 sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
381 bv_out->bv_offset + ctx->offset_out);
383 ctx->offset_in += 1 << SECTOR_SHIFT;
384 if (ctx->offset_in >= bv_in->bv_len) {
389 ctx->offset_out += 1 << SECTOR_SHIFT;
390 if (ctx->offset_out >= bv_out->bv_len) {
395 if (cc->iv_gen_ops) {
396 r = cc->iv_gen_ops->generator(cc, iv, ctx->sector);
401 ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
402 1 << SECTOR_SHIFT, iv);
404 if (bio_data_dir(ctx->bio_in) == WRITE)
405 r = crypto_ablkcipher_encrypt(req);
407 r = crypto_ablkcipher_decrypt(req);
412 static void kcryptd_async_done(struct crypto_async_request *async_req,
414 static void crypt_alloc_req(struct crypt_config *cc,
415 struct convert_context *ctx)
418 cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
419 ablkcipher_request_set_tfm(cc->req, cc->tfm);
420 ablkcipher_request_set_callback(cc->req, CRYPTO_TFM_REQ_MAY_BACKLOG |
421 CRYPTO_TFM_REQ_MAY_SLEEP,
423 dmreq_of_req(cc, cc->req));
427 * Encrypt / decrypt data from one bio to another one (can be the same one)
429 static int crypt_convert(struct crypt_config *cc,
430 struct convert_context *ctx)
434 atomic_set(&ctx->pending, 1);
436 while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
437 ctx->idx_out < ctx->bio_out->bi_vcnt) {
439 crypt_alloc_req(cc, ctx);
441 atomic_inc(&ctx->pending);
443 r = crypt_convert_block(cc, ctx, cc->req);
448 wait_for_completion(&ctx->restart);
449 INIT_COMPLETION(ctx->restart);
458 atomic_dec(&ctx->pending);
465 atomic_dec(&ctx->pending);
473 static void dm_crypt_bio_destructor(struct bio *bio)
475 struct dm_crypt_io *io = bio->bi_private;
476 struct crypt_config *cc = io->target->private;
478 bio_free(bio, cc->bs);
482 * Generate a new unfragmented bio with the given size
483 * This should never violate the device limitations
484 * May return a smaller bio when running out of pages, indicated by
485 * *out_of_pages set to 1.
487 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
488 unsigned *out_of_pages)
490 struct crypt_config *cc = io->target->private;
492 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
493 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
497 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
501 clone_init(io, clone);
504 for (i = 0; i < nr_iovecs; i++) {
505 page = mempool_alloc(cc->page_pool, gfp_mask);
512 * if additional pages cannot be allocated without waiting,
513 * return a partially allocated bio, the caller will then try
514 * to allocate additional bios while submitting this partial bio
516 if (i == (MIN_BIO_PAGES - 1))
517 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
519 len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
521 if (!bio_add_page(clone, page, len, 0)) {
522 mempool_free(page, cc->page_pool);
529 if (!clone->bi_size) {
537 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
542 for (i = 0; i < clone->bi_vcnt; i++) {
543 bv = bio_iovec_idx(clone, i);
544 BUG_ON(!bv->bv_page);
545 mempool_free(bv->bv_page, cc->page_pool);
550 static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti,
551 struct bio *bio, sector_t sector)
553 struct crypt_config *cc = ti->private;
554 struct dm_crypt_io *io;
556 io = mempool_alloc(cc->io_pool, GFP_NOIO);
562 atomic_set(&io->pending, 0);
567 static void crypt_inc_pending(struct dm_crypt_io *io)
569 atomic_inc(&io->pending);
573 * One of the bios was finished. Check for completion of
574 * the whole request and correctly clean up the buffer.
575 * If base_io is set, wait for the last fragment to complete.
577 static void crypt_dec_pending(struct dm_crypt_io *io)
579 struct crypt_config *cc = io->target->private;
580 struct bio *base_bio = io->base_bio;
581 struct dm_crypt_io *base_io = io->base_io;
582 int error = io->error;
584 if (!atomic_dec_and_test(&io->pending))
587 mempool_free(io, cc->io_pool);
589 if (likely(!base_io))
590 bio_endio(base_bio, error);
592 if (error && !base_io->error)
593 base_io->error = error;
594 crypt_dec_pending(base_io);
599 * kcryptd/kcryptd_io:
601 * Needed because it would be very unwise to do decryption in an
604 * kcryptd performs the actual encryption or decryption.
606 * kcryptd_io performs the IO submission.
608 * They must be separated as otherwise the final stages could be
609 * starved by new requests which can block in the first stages due
610 * to memory allocation.
612 static void crypt_endio(struct bio *clone, int error)
614 struct dm_crypt_io *io = clone->bi_private;
615 struct crypt_config *cc = io->target->private;
616 unsigned rw = bio_data_dir(clone);
618 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
622 * free the processed pages
625 crypt_free_buffer_pages(cc, clone);
629 if (rw == READ && !error) {
630 kcryptd_queue_crypt(io);
637 crypt_dec_pending(io);
640 static void clone_init(struct dm_crypt_io *io, struct bio *clone)
642 struct crypt_config *cc = io->target->private;
644 clone->bi_private = io;
645 clone->bi_end_io = crypt_endio;
646 clone->bi_bdev = cc->dev->bdev;
647 clone->bi_rw = io->base_bio->bi_rw;
648 clone->bi_destructor = dm_crypt_bio_destructor;
651 static void kcryptd_io_read(struct dm_crypt_io *io)
653 struct crypt_config *cc = io->target->private;
654 struct bio *base_bio = io->base_bio;
657 crypt_inc_pending(io);
660 * The block layer might modify the bvec array, so always
661 * copy the required bvecs because we need the original
662 * one in order to decrypt the whole bio data *afterwards*.
664 clone = bio_alloc_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs);
665 if (unlikely(!clone)) {
667 crypt_dec_pending(io);
671 clone_init(io, clone);
673 clone->bi_vcnt = bio_segments(base_bio);
674 clone->bi_size = base_bio->bi_size;
675 clone->bi_sector = cc->start + io->sector;
676 memcpy(clone->bi_io_vec, bio_iovec(base_bio),
677 sizeof(struct bio_vec) * clone->bi_vcnt);
679 generic_make_request(clone);
682 static void kcryptd_io_write(struct dm_crypt_io *io)
684 struct bio *clone = io->ctx.bio_out;
685 generic_make_request(clone);
688 static void kcryptd_io(struct work_struct *work)
690 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
692 if (bio_data_dir(io->base_bio) == READ)
695 kcryptd_io_write(io);
698 static void kcryptd_queue_io(struct dm_crypt_io *io)
700 struct crypt_config *cc = io->target->private;
702 INIT_WORK(&io->work, kcryptd_io);
703 queue_work(cc->io_queue, &io->work);
706 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
707 int error, int async)
709 struct bio *clone = io->ctx.bio_out;
710 struct crypt_config *cc = io->target->private;
712 if (unlikely(error < 0)) {
713 crypt_free_buffer_pages(cc, clone);
716 crypt_dec_pending(io);
720 /* crypt_convert should have filled the clone bio */
721 BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
723 clone->bi_sector = cc->start + io->sector;
726 kcryptd_queue_io(io);
728 generic_make_request(clone);
731 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
733 struct crypt_config *cc = io->target->private;
735 struct dm_crypt_io *new_io;
737 unsigned out_of_pages = 0;
738 unsigned remaining = io->base_bio->bi_size;
739 sector_t sector = io->sector;
743 * Prevent io from disappearing until this function completes.
745 crypt_inc_pending(io);
746 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
749 * The allocated buffers can be smaller than the whole bio,
750 * so repeat the whole process until all the data can be handled.
753 clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
754 if (unlikely(!clone)) {
759 io->ctx.bio_out = clone;
762 remaining -= clone->bi_size;
763 sector += bio_sectors(clone);
765 crypt_inc_pending(io);
766 r = crypt_convert(cc, &io->ctx);
767 crypt_finished = atomic_dec_and_test(&io->ctx.pending);
769 /* Encryption was already finished, submit io now */
770 if (crypt_finished) {
771 kcryptd_crypt_write_io_submit(io, r, 0);
774 * If there was an error, do not try next fragments.
775 * For async, error is processed in async handler.
784 * Out of memory -> run queues
785 * But don't wait if split was due to the io size restriction
787 if (unlikely(out_of_pages))
788 congestion_wait(BLK_RW_ASYNC, HZ/100);
791 * With async crypto it is unsafe to share the crypto context
792 * between fragments, so switch to a new dm_crypt_io structure.
794 if (unlikely(!crypt_finished && remaining)) {
795 new_io = crypt_io_alloc(io->target, io->base_bio,
797 crypt_inc_pending(new_io);
798 crypt_convert_init(cc, &new_io->ctx, NULL,
799 io->base_bio, sector);
800 new_io->ctx.idx_in = io->ctx.idx_in;
801 new_io->ctx.offset_in = io->ctx.offset_in;
804 * Fragments after the first use the base_io
808 new_io->base_io = io;
810 new_io->base_io = io->base_io;
811 crypt_inc_pending(io->base_io);
812 crypt_dec_pending(io);
819 crypt_dec_pending(io);
822 static void kcryptd_crypt_read_done(struct dm_crypt_io *io, int error)
824 if (unlikely(error < 0))
827 crypt_dec_pending(io);
830 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
832 struct crypt_config *cc = io->target->private;
835 crypt_inc_pending(io);
837 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
840 r = crypt_convert(cc, &io->ctx);
842 if (atomic_dec_and_test(&io->ctx.pending))
843 kcryptd_crypt_read_done(io, r);
845 crypt_dec_pending(io);
848 static void kcryptd_async_done(struct crypto_async_request *async_req,
851 struct dm_crypt_request *dmreq = async_req->data;
852 struct convert_context *ctx = dmreq->ctx;
853 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
854 struct crypt_config *cc = io->target->private;
856 if (error == -EINPROGRESS) {
857 complete(&ctx->restart);
861 mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool);
863 if (!atomic_dec_and_test(&ctx->pending))
866 if (bio_data_dir(io->base_bio) == READ)
867 kcryptd_crypt_read_done(io, error);
869 kcryptd_crypt_write_io_submit(io, error, 1);
872 static void kcryptd_crypt(struct work_struct *work)
874 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
876 if (bio_data_dir(io->base_bio) == READ)
877 kcryptd_crypt_read_convert(io);
879 kcryptd_crypt_write_convert(io);
882 static void kcryptd_queue_crypt(struct dm_crypt_io *io)
884 struct crypt_config *cc = io->target->private;
886 INIT_WORK(&io->work, kcryptd_crypt);
887 queue_work(cc->crypt_queue, &io->work);
891 * Decode key from its hex representation
893 static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
901 for (i = 0; i < size; i++) {
905 key[i] = (u8)simple_strtoul(buffer, &endp, 16);
907 if (endp != &buffer[2])
918 * Encode key into its hex representation
920 static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
924 for (i = 0; i < size; i++) {
925 sprintf(hex, "%02x", *key);
931 static int crypt_set_key(struct crypt_config *cc, char *key)
933 unsigned key_size = strlen(key) >> 1;
935 if (cc->key_size && cc->key_size != key_size)
938 cc->key_size = key_size; /* initial settings */
940 if ((!key_size && strcmp(key, "-")) ||
941 (key_size && crypt_decode_key(cc->key, key, key_size) < 0))
944 set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
946 return crypto_ablkcipher_setkey(cc->tfm, cc->key, cc->key_size);
949 static int crypt_wipe_key(struct crypt_config *cc)
951 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
952 memset(&cc->key, 0, cc->key_size * sizeof(u8));
953 return crypto_ablkcipher_setkey(cc->tfm, cc->key, cc->key_size);
957 * Construct an encryption mapping:
958 * <cipher> <key> <iv_offset> <dev_path> <start>
960 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
962 struct crypt_config *cc;
963 struct crypto_ablkcipher *tfm;
969 unsigned int key_size;
970 unsigned long long tmpll;
973 ti->error = "Not enough arguments";
978 cipher = strsep(&tmp, "-");
979 chainmode = strsep(&tmp, "-");
980 ivopts = strsep(&tmp, "-");
981 ivmode = strsep(&ivopts, ":");
984 DMWARN("Unexpected additional cipher options");
986 key_size = strlen(argv[1]) >> 1;
988 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
991 "Cannot allocate transparent encryption context";
995 /* Compatibility mode for old dm-crypt cipher strings */
996 if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
1001 if (strcmp(chainmode, "ecb") && !ivmode) {
1002 ti->error = "This chaining mode requires an IV mechanism";
1006 if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1007 chainmode, cipher) >= CRYPTO_MAX_ALG_NAME) {
1008 ti->error = "Chain mode + cipher name is too long";
1012 tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
1014 ti->error = "Error allocating crypto tfm";
1018 strcpy(cc->cipher, cipher);
1019 strcpy(cc->chainmode, chainmode);
1022 if (crypt_set_key(cc, argv[1]) < 0) {
1023 ti->error = "Error decoding and setting key";
1028 * Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi".
1029 * See comments at iv code
1033 cc->iv_gen_ops = NULL;
1034 else if (strcmp(ivmode, "plain") == 0)
1035 cc->iv_gen_ops = &crypt_iv_plain_ops;
1036 else if (strcmp(ivmode, "essiv") == 0)
1037 cc->iv_gen_ops = &crypt_iv_essiv_ops;
1038 else if (strcmp(ivmode, "benbi") == 0)
1039 cc->iv_gen_ops = &crypt_iv_benbi_ops;
1040 else if (strcmp(ivmode, "null") == 0)
1041 cc->iv_gen_ops = &crypt_iv_null_ops;
1043 ti->error = "Invalid IV mode";
1047 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr &&
1048 cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
1051 cc->iv_size = crypto_ablkcipher_ivsize(tfm);
1053 /* at least a 64 bit sector number should fit in our buffer */
1054 cc->iv_size = max(cc->iv_size,
1055 (unsigned int)(sizeof(u64) / sizeof(u8)));
1057 if (cc->iv_gen_ops) {
1058 DMWARN("Selected cipher does not support IVs");
1059 if (cc->iv_gen_ops->dtr)
1060 cc->iv_gen_ops->dtr(cc);
1061 cc->iv_gen_ops = NULL;
1065 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1067 ti->error = "Cannot allocate crypt io mempool";
1071 cc->dmreq_start = sizeof(struct ablkcipher_request);
1072 cc->dmreq_start += crypto_ablkcipher_reqsize(tfm);
1073 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
1074 cc->dmreq_start += crypto_ablkcipher_alignmask(tfm) &
1075 ~(crypto_tfm_ctx_alignment() - 1);
1077 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1078 sizeof(struct dm_crypt_request) + cc->iv_size);
1079 if (!cc->req_pool) {
1080 ti->error = "Cannot allocate crypt request mempool";
1085 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1086 if (!cc->page_pool) {
1087 ti->error = "Cannot allocate page mempool";
1091 cc->bs = bioset_create(MIN_IOS, 0);
1093 ti->error = "Cannot allocate crypt bioset";
1097 if (sscanf(argv[2], "%llu", &tmpll) != 1) {
1098 ti->error = "Invalid iv_offset sector";
1101 cc->iv_offset = tmpll;
1103 if (sscanf(argv[4], "%llu", &tmpll) != 1) {
1104 ti->error = "Invalid device sector";
1109 if (dm_get_device(ti, argv[3], cc->start, ti->len,
1110 dm_table_get_mode(ti->table), &cc->dev)) {
1111 ti->error = "Device lookup failed";
1115 if (ivmode && cc->iv_gen_ops) {
1117 *(ivopts - 1) = ':';
1118 cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL);
1120 ti->error = "Error kmallocing iv_mode string";
1121 goto bad_ivmode_string;
1123 strcpy(cc->iv_mode, ivmode);
1127 cc->io_queue = create_singlethread_workqueue("kcryptd_io");
1128 if (!cc->io_queue) {
1129 ti->error = "Couldn't create kcryptd io queue";
1133 cc->crypt_queue = create_singlethread_workqueue("kcryptd");
1134 if (!cc->crypt_queue) {
1135 ti->error = "Couldn't create kcryptd queue";
1136 goto bad_crypt_queue;
1139 ti->num_flush_requests = 1;
1144 destroy_workqueue(cc->io_queue);
1148 dm_put_device(ti, cc->dev);
1150 bioset_free(cc->bs);
1152 mempool_destroy(cc->page_pool);
1154 mempool_destroy(cc->req_pool);
1156 mempool_destroy(cc->io_pool);
1158 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1159 cc->iv_gen_ops->dtr(cc);
1161 crypto_free_ablkcipher(tfm);
1163 /* Must zero key material before freeing */
1168 static void crypt_dtr(struct dm_target *ti)
1170 struct crypt_config *cc = (struct crypt_config *) ti->private;
1172 destroy_workqueue(cc->io_queue);
1173 destroy_workqueue(cc->crypt_queue);
1176 mempool_free(cc->req, cc->req_pool);
1178 bioset_free(cc->bs);
1179 mempool_destroy(cc->page_pool);
1180 mempool_destroy(cc->req_pool);
1181 mempool_destroy(cc->io_pool);
1184 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1185 cc->iv_gen_ops->dtr(cc);
1186 crypto_free_ablkcipher(cc->tfm);
1187 dm_put_device(ti, cc->dev);
1189 /* Must zero key material before freeing */
1193 static int crypt_map(struct dm_target *ti, struct bio *bio,
1194 union map_info *map_context)
1196 struct dm_crypt_io *io;
1197 struct crypt_config *cc;
1199 if (unlikely(bio_empty_barrier(bio))) {
1201 bio->bi_bdev = cc->dev->bdev;
1202 return DM_MAPIO_REMAPPED;
1205 io = crypt_io_alloc(ti, bio, bio->bi_sector - ti->begin);
1207 if (bio_data_dir(io->base_bio) == READ)
1208 kcryptd_queue_io(io);
1210 kcryptd_queue_crypt(io);
1212 return DM_MAPIO_SUBMITTED;
1215 static int crypt_status(struct dm_target *ti, status_type_t type,
1216 char *result, unsigned int maxlen)
1218 struct crypt_config *cc = (struct crypt_config *) ti->private;
1219 unsigned int sz = 0;
1222 case STATUSTYPE_INFO:
1226 case STATUSTYPE_TABLE:
1228 DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode,
1231 DMEMIT("%s-%s ", cc->cipher, cc->chainmode);
1233 if (cc->key_size > 0) {
1234 if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1237 crypt_encode_key(result + sz, cc->key, cc->key_size);
1238 sz += cc->key_size << 1;
1245 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1246 cc->dev->name, (unsigned long long)cc->start);
1252 static void crypt_postsuspend(struct dm_target *ti)
1254 struct crypt_config *cc = ti->private;
1256 set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1259 static int crypt_preresume(struct dm_target *ti)
1261 struct crypt_config *cc = ti->private;
1263 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1264 DMERR("aborting resume - crypt key is not set.");
1271 static void crypt_resume(struct dm_target *ti)
1273 struct crypt_config *cc = ti->private;
1275 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1278 /* Message interface
1282 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1284 struct crypt_config *cc = ti->private;
1289 if (!strnicmp(argv[0], MESG_STR("key"))) {
1290 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1291 DMWARN("not suspended during key manipulation.");
1294 if (argc == 3 && !strnicmp(argv[1], MESG_STR("set")))
1295 return crypt_set_key(cc, argv[2]);
1296 if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe")))
1297 return crypt_wipe_key(cc);
1301 DMWARN("unrecognised message received.");
1305 static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1306 struct bio_vec *biovec, int max_size)
1308 struct crypt_config *cc = ti->private;
1309 struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1311 if (!q->merge_bvec_fn)
1314 bvm->bi_bdev = cc->dev->bdev;
1315 bvm->bi_sector = cc->start + bvm->bi_sector - ti->begin;
1317 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1320 static int crypt_iterate_devices(struct dm_target *ti,
1321 iterate_devices_callout_fn fn, void *data)
1323 struct crypt_config *cc = ti->private;
1325 return fn(ti, cc->dev, cc->start, ti->len, data);
1328 static struct target_type crypt_target = {
1330 .version = {1, 7, 0},
1331 .module = THIS_MODULE,
1335 .status = crypt_status,
1336 .postsuspend = crypt_postsuspend,
1337 .preresume = crypt_preresume,
1338 .resume = crypt_resume,
1339 .message = crypt_message,
1340 .merge = crypt_merge,
1341 .iterate_devices = crypt_iterate_devices,
1344 static int __init dm_crypt_init(void)
1348 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1349 if (!_crypt_io_pool)
1352 r = dm_register_target(&crypt_target);
1354 DMERR("register failed %d", r);
1355 kmem_cache_destroy(_crypt_io_pool);
1361 static void __exit dm_crypt_exit(void)
1363 dm_unregister_target(&crypt_target);
1364 kmem_cache_destroy(_crypt_io_pool);
1367 module_init(dm_crypt_init);
1368 module_exit(dm_crypt_exit);
1370 MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1371 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1372 MODULE_LICENSE("GPL");