2 * Copyright (C) 2003 Christophe Saout <christophe@saout.de>
3 * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
4 * Copyright (C) 2006-2009 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"
31 * context holding the current state of a multi-part conversion
33 struct convert_context {
34 struct completion restart;
37 unsigned int offset_in;
38 unsigned int offset_out;
46 * per bio private data
49 struct dm_target *target;
51 struct work_struct work;
53 struct convert_context ctx;
58 struct dm_crypt_io *base_io;
61 struct dm_crypt_request {
62 struct convert_context *ctx;
63 struct scatterlist sg_in;
64 struct scatterlist sg_out;
69 struct crypt_iv_operations {
70 int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
72 void (*dtr)(struct crypt_config *cc);
73 int (*init)(struct crypt_config *cc);
74 int (*wipe)(struct crypt_config *cc);
75 int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
78 struct iv_essiv_private {
79 struct crypto_cipher *tfm;
80 struct crypto_hash *hash_tfm;
84 struct iv_benbi_private {
89 * Crypt: maps a linear range of a block device
90 * and encrypts / decrypts at the same time.
92 enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
98 * pool for per bio private data, crypto requests and
99 * encryption requeusts/buffer pages
103 mempool_t *page_pool;
106 struct workqueue_struct *io_queue;
107 struct workqueue_struct *crypt_queue;
112 struct crypt_iv_operations *iv_gen_ops;
114 struct iv_essiv_private essiv;
115 struct iv_benbi_private benbi;
118 unsigned int iv_size;
121 * Layout of each crypto request:
123 * struct ablkcipher_request
126 * struct dm_crypt_request
130 * The padding is added so that dm_crypt_request and the IV are
133 unsigned int dmreq_start;
134 struct ablkcipher_request *req;
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 * plain64: the initial vector is the 64-bit little-endian version of the sector
158 * number, padded with zeros if necessary.
160 * essiv: "encrypted sector|salt initial vector", the sector number is
161 * encrypted with the bulk cipher using a salt as key. The salt
162 * should be derived from the bulk cipher's key via hashing.
164 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
165 * (needed for LRW-32-AES and possible other narrow block modes)
167 * null: the initial vector is always zero. Provides compatibility with
168 * obsolete loop_fish2 devices. Do not use for new devices.
170 * plumb: unimplemented, see:
171 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
174 static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
176 memset(iv, 0, cc->iv_size);
177 *(u32 *)iv = cpu_to_le32(sector & 0xffffffff);
182 static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
185 memset(iv, 0, cc->iv_size);
186 *(u64 *)iv = cpu_to_le64(sector);
191 /* Initialise ESSIV - compute salt but no local memory allocations */
192 static int crypt_iv_essiv_init(struct crypt_config *cc)
194 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
195 struct hash_desc desc;
196 struct scatterlist sg;
199 sg_init_one(&sg, cc->key, cc->key_size);
200 desc.tfm = essiv->hash_tfm;
201 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
203 err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt);
207 return crypto_cipher_setkey(essiv->tfm, essiv->salt,
208 crypto_hash_digestsize(essiv->hash_tfm));
211 /* Wipe salt and reset key derived from volume key */
212 static int crypt_iv_essiv_wipe(struct crypt_config *cc)
214 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
215 unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm);
217 memset(essiv->salt, 0, salt_size);
219 return crypto_cipher_setkey(essiv->tfm, essiv->salt, salt_size);
222 static void crypt_iv_essiv_dtr(struct crypt_config *cc)
224 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
226 crypto_free_cipher(essiv->tfm);
229 crypto_free_hash(essiv->hash_tfm);
230 essiv->hash_tfm = NULL;
236 static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
239 struct crypto_cipher *essiv_tfm = NULL;
240 struct crypto_hash *hash_tfm = NULL;
245 ti->error = "Digest algorithm missing for ESSIV mode";
249 /* Allocate hash algorithm */
250 hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
251 if (IS_ERR(hash_tfm)) {
252 ti->error = "Error initializing ESSIV hash";
253 err = PTR_ERR(hash_tfm);
257 salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL);
259 ti->error = "Error kmallocing salt storage in ESSIV";
264 /* Allocate essiv_tfm */
265 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
266 if (IS_ERR(essiv_tfm)) {
267 ti->error = "Error allocating crypto tfm for ESSIV";
268 err = PTR_ERR(essiv_tfm);
271 if (crypto_cipher_blocksize(essiv_tfm) !=
272 crypto_ablkcipher_ivsize(cc->tfm)) {
273 ti->error = "Block size of ESSIV cipher does "
274 "not match IV size of block cipher";
279 cc->iv_gen_private.essiv.salt = salt;
280 cc->iv_gen_private.essiv.tfm = essiv_tfm;
281 cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
286 if (essiv_tfm && !IS_ERR(essiv_tfm))
287 crypto_free_cipher(essiv_tfm);
288 if (hash_tfm && !IS_ERR(hash_tfm))
289 crypto_free_hash(hash_tfm);
294 static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
296 memset(iv, 0, cc->iv_size);
297 *(u64 *)iv = cpu_to_le64(sector);
298 crypto_cipher_encrypt_one(cc->iv_gen_private.essiv.tfm, iv, iv);
302 static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
305 unsigned bs = crypto_ablkcipher_blocksize(cc->tfm);
308 /* we need to calculate how far we must shift the sector count
309 * to get the cipher block count, we use this shift in _gen */
311 if (1 << log != bs) {
312 ti->error = "cypher blocksize is not a power of 2";
317 ti->error = "cypher blocksize is > 512";
321 cc->iv_gen_private.benbi.shift = 9 - log;
326 static void crypt_iv_benbi_dtr(struct crypt_config *cc)
330 static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
334 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
336 val = cpu_to_be64(((u64)sector << cc->iv_gen_private.benbi.shift) + 1);
337 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
342 static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
344 memset(iv, 0, cc->iv_size);
349 static struct crypt_iv_operations crypt_iv_plain_ops = {
350 .generator = crypt_iv_plain_gen
353 static struct crypt_iv_operations crypt_iv_plain64_ops = {
354 .generator = crypt_iv_plain64_gen
357 static struct crypt_iv_operations crypt_iv_essiv_ops = {
358 .ctr = crypt_iv_essiv_ctr,
359 .dtr = crypt_iv_essiv_dtr,
360 .init = crypt_iv_essiv_init,
361 .wipe = crypt_iv_essiv_wipe,
362 .generator = crypt_iv_essiv_gen
365 static struct crypt_iv_operations crypt_iv_benbi_ops = {
366 .ctr = crypt_iv_benbi_ctr,
367 .dtr = crypt_iv_benbi_dtr,
368 .generator = crypt_iv_benbi_gen
371 static struct crypt_iv_operations crypt_iv_null_ops = {
372 .generator = crypt_iv_null_gen
375 static void crypt_convert_init(struct crypt_config *cc,
376 struct convert_context *ctx,
377 struct bio *bio_out, struct bio *bio_in,
380 ctx->bio_in = bio_in;
381 ctx->bio_out = bio_out;
384 ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
385 ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
386 ctx->sector = sector + cc->iv_offset;
387 init_completion(&ctx->restart);
390 static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
391 struct ablkcipher_request *req)
393 return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
396 static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc,
397 struct dm_crypt_request *dmreq)
399 return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start);
402 static int crypt_convert_block(struct crypt_config *cc,
403 struct convert_context *ctx,
404 struct ablkcipher_request *req)
406 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
407 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
408 struct dm_crypt_request *dmreq;
412 dmreq = dmreq_of_req(cc, req);
413 iv = (u8 *)ALIGN((unsigned long)(dmreq + 1),
414 crypto_ablkcipher_alignmask(cc->tfm) + 1);
417 sg_init_table(&dmreq->sg_in, 1);
418 sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
419 bv_in->bv_offset + ctx->offset_in);
421 sg_init_table(&dmreq->sg_out, 1);
422 sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
423 bv_out->bv_offset + ctx->offset_out);
425 ctx->offset_in += 1 << SECTOR_SHIFT;
426 if (ctx->offset_in >= bv_in->bv_len) {
431 ctx->offset_out += 1 << SECTOR_SHIFT;
432 if (ctx->offset_out >= bv_out->bv_len) {
437 if (cc->iv_gen_ops) {
438 r = cc->iv_gen_ops->generator(cc, iv, ctx->sector);
443 ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
444 1 << SECTOR_SHIFT, iv);
446 if (bio_data_dir(ctx->bio_in) == WRITE)
447 r = crypto_ablkcipher_encrypt(req);
449 r = crypto_ablkcipher_decrypt(req);
454 static void kcryptd_async_done(struct crypto_async_request *async_req,
456 static void crypt_alloc_req(struct crypt_config *cc,
457 struct convert_context *ctx)
460 cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
461 ablkcipher_request_set_tfm(cc->req, cc->tfm);
462 ablkcipher_request_set_callback(cc->req, CRYPTO_TFM_REQ_MAY_BACKLOG |
463 CRYPTO_TFM_REQ_MAY_SLEEP,
465 dmreq_of_req(cc, cc->req));
469 * Encrypt / decrypt data from one bio to another one (can be the same one)
471 static int crypt_convert(struct crypt_config *cc,
472 struct convert_context *ctx)
476 atomic_set(&ctx->pending, 1);
478 while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
479 ctx->idx_out < ctx->bio_out->bi_vcnt) {
481 crypt_alloc_req(cc, ctx);
483 atomic_inc(&ctx->pending);
485 r = crypt_convert_block(cc, ctx, cc->req);
490 wait_for_completion(&ctx->restart);
491 INIT_COMPLETION(ctx->restart);
500 atomic_dec(&ctx->pending);
507 atomic_dec(&ctx->pending);
515 static void dm_crypt_bio_destructor(struct bio *bio)
517 struct dm_crypt_io *io = bio->bi_private;
518 struct crypt_config *cc = io->target->private;
520 bio_free(bio, cc->bs);
524 * Generate a new unfragmented bio with the given size
525 * This should never violate the device limitations
526 * May return a smaller bio when running out of pages, indicated by
527 * *out_of_pages set to 1.
529 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
530 unsigned *out_of_pages)
532 struct crypt_config *cc = io->target->private;
534 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
535 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
539 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
543 clone_init(io, clone);
546 for (i = 0; i < nr_iovecs; i++) {
547 page = mempool_alloc(cc->page_pool, gfp_mask);
554 * if additional pages cannot be allocated without waiting,
555 * return a partially allocated bio, the caller will then try
556 * to allocate additional bios while submitting this partial bio
558 if (i == (MIN_BIO_PAGES - 1))
559 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
561 len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
563 if (!bio_add_page(clone, page, len, 0)) {
564 mempool_free(page, cc->page_pool);
571 if (!clone->bi_size) {
579 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
584 for (i = 0; i < clone->bi_vcnt; i++) {
585 bv = bio_iovec_idx(clone, i);
586 BUG_ON(!bv->bv_page);
587 mempool_free(bv->bv_page, cc->page_pool);
592 static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti,
593 struct bio *bio, sector_t sector)
595 struct crypt_config *cc = ti->private;
596 struct dm_crypt_io *io;
598 io = mempool_alloc(cc->io_pool, GFP_NOIO);
604 atomic_set(&io->pending, 0);
609 static void crypt_inc_pending(struct dm_crypt_io *io)
611 atomic_inc(&io->pending);
615 * One of the bios was finished. Check for completion of
616 * the whole request and correctly clean up the buffer.
617 * If base_io is set, wait for the last fragment to complete.
619 static void crypt_dec_pending(struct dm_crypt_io *io)
621 struct crypt_config *cc = io->target->private;
622 struct bio *base_bio = io->base_bio;
623 struct dm_crypt_io *base_io = io->base_io;
624 int error = io->error;
626 if (!atomic_dec_and_test(&io->pending))
629 mempool_free(io, cc->io_pool);
631 if (likely(!base_io))
632 bio_endio(base_bio, error);
634 if (error && !base_io->error)
635 base_io->error = error;
636 crypt_dec_pending(base_io);
641 * kcryptd/kcryptd_io:
643 * Needed because it would be very unwise to do decryption in an
646 * kcryptd performs the actual encryption or decryption.
648 * kcryptd_io performs the IO submission.
650 * They must be separated as otherwise the final stages could be
651 * starved by new requests which can block in the first stages due
652 * to memory allocation.
654 static void crypt_endio(struct bio *clone, int error)
656 struct dm_crypt_io *io = clone->bi_private;
657 struct crypt_config *cc = io->target->private;
658 unsigned rw = bio_data_dir(clone);
660 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
664 * free the processed pages
667 crypt_free_buffer_pages(cc, clone);
671 if (rw == READ && !error) {
672 kcryptd_queue_crypt(io);
679 crypt_dec_pending(io);
682 static void clone_init(struct dm_crypt_io *io, struct bio *clone)
684 struct crypt_config *cc = io->target->private;
686 clone->bi_private = io;
687 clone->bi_end_io = crypt_endio;
688 clone->bi_bdev = cc->dev->bdev;
689 clone->bi_rw = io->base_bio->bi_rw;
690 clone->bi_destructor = dm_crypt_bio_destructor;
693 static void kcryptd_io_read(struct dm_crypt_io *io)
695 struct crypt_config *cc = io->target->private;
696 struct bio *base_bio = io->base_bio;
699 crypt_inc_pending(io);
702 * The block layer might modify the bvec array, so always
703 * copy the required bvecs because we need the original
704 * one in order to decrypt the whole bio data *afterwards*.
706 clone = bio_alloc_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs);
707 if (unlikely(!clone)) {
709 crypt_dec_pending(io);
713 clone_init(io, clone);
715 clone->bi_vcnt = bio_segments(base_bio);
716 clone->bi_size = base_bio->bi_size;
717 clone->bi_sector = cc->start + io->sector;
718 memcpy(clone->bi_io_vec, bio_iovec(base_bio),
719 sizeof(struct bio_vec) * clone->bi_vcnt);
721 generic_make_request(clone);
724 static void kcryptd_io_write(struct dm_crypt_io *io)
726 struct bio *clone = io->ctx.bio_out;
727 generic_make_request(clone);
730 static void kcryptd_io(struct work_struct *work)
732 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
734 if (bio_data_dir(io->base_bio) == READ)
737 kcryptd_io_write(io);
740 static void kcryptd_queue_io(struct dm_crypt_io *io)
742 struct crypt_config *cc = io->target->private;
744 INIT_WORK(&io->work, kcryptd_io);
745 queue_work(cc->io_queue, &io->work);
748 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
749 int error, int async)
751 struct bio *clone = io->ctx.bio_out;
752 struct crypt_config *cc = io->target->private;
754 if (unlikely(error < 0)) {
755 crypt_free_buffer_pages(cc, clone);
758 crypt_dec_pending(io);
762 /* crypt_convert should have filled the clone bio */
763 BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
765 clone->bi_sector = cc->start + io->sector;
768 kcryptd_queue_io(io);
770 generic_make_request(clone);
773 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
775 struct crypt_config *cc = io->target->private;
777 struct dm_crypt_io *new_io;
779 unsigned out_of_pages = 0;
780 unsigned remaining = io->base_bio->bi_size;
781 sector_t sector = io->sector;
785 * Prevent io from disappearing until this function completes.
787 crypt_inc_pending(io);
788 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
791 * The allocated buffers can be smaller than the whole bio,
792 * so repeat the whole process until all the data can be handled.
795 clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
796 if (unlikely(!clone)) {
801 io->ctx.bio_out = clone;
804 remaining -= clone->bi_size;
805 sector += bio_sectors(clone);
807 crypt_inc_pending(io);
808 r = crypt_convert(cc, &io->ctx);
809 crypt_finished = atomic_dec_and_test(&io->ctx.pending);
811 /* Encryption was already finished, submit io now */
812 if (crypt_finished) {
813 kcryptd_crypt_write_io_submit(io, r, 0);
816 * If there was an error, do not try next fragments.
817 * For async, error is processed in async handler.
826 * Out of memory -> run queues
827 * But don't wait if split was due to the io size restriction
829 if (unlikely(out_of_pages))
830 congestion_wait(BLK_RW_ASYNC, HZ/100);
833 * With async crypto it is unsafe to share the crypto context
834 * between fragments, so switch to a new dm_crypt_io structure.
836 if (unlikely(!crypt_finished && remaining)) {
837 new_io = crypt_io_alloc(io->target, io->base_bio,
839 crypt_inc_pending(new_io);
840 crypt_convert_init(cc, &new_io->ctx, NULL,
841 io->base_bio, sector);
842 new_io->ctx.idx_in = io->ctx.idx_in;
843 new_io->ctx.offset_in = io->ctx.offset_in;
846 * Fragments after the first use the base_io
850 new_io->base_io = io;
852 new_io->base_io = io->base_io;
853 crypt_inc_pending(io->base_io);
854 crypt_dec_pending(io);
861 crypt_dec_pending(io);
864 static void kcryptd_crypt_read_done(struct dm_crypt_io *io, int error)
866 if (unlikely(error < 0))
869 crypt_dec_pending(io);
872 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
874 struct crypt_config *cc = io->target->private;
877 crypt_inc_pending(io);
879 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
882 r = crypt_convert(cc, &io->ctx);
884 if (atomic_dec_and_test(&io->ctx.pending))
885 kcryptd_crypt_read_done(io, r);
887 crypt_dec_pending(io);
890 static void kcryptd_async_done(struct crypto_async_request *async_req,
893 struct dm_crypt_request *dmreq = async_req->data;
894 struct convert_context *ctx = dmreq->ctx;
895 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
896 struct crypt_config *cc = io->target->private;
898 if (error == -EINPROGRESS) {
899 complete(&ctx->restart);
903 mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool);
905 if (!atomic_dec_and_test(&ctx->pending))
908 if (bio_data_dir(io->base_bio) == READ)
909 kcryptd_crypt_read_done(io, error);
911 kcryptd_crypt_write_io_submit(io, error, 1);
914 static void kcryptd_crypt(struct work_struct *work)
916 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
918 if (bio_data_dir(io->base_bio) == READ)
919 kcryptd_crypt_read_convert(io);
921 kcryptd_crypt_write_convert(io);
924 static void kcryptd_queue_crypt(struct dm_crypt_io *io)
926 struct crypt_config *cc = io->target->private;
928 INIT_WORK(&io->work, kcryptd_crypt);
929 queue_work(cc->crypt_queue, &io->work);
933 * Decode key from its hex representation
935 static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
943 for (i = 0; i < size; i++) {
947 key[i] = (u8)simple_strtoul(buffer, &endp, 16);
949 if (endp != &buffer[2])
960 * Encode key into its hex representation
962 static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
966 for (i = 0; i < size; i++) {
967 sprintf(hex, "%02x", *key);
973 static int crypt_set_key(struct crypt_config *cc, char *key)
975 /* The key size may not be changed. */
976 if (cc->key_size != (strlen(key) >> 1))
979 /* Hyphen (which gives a key_size of zero) means there is no key. */
980 if (!cc->key_size && strcmp(key, "-"))
983 if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
986 set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
988 return crypto_ablkcipher_setkey(cc->tfm, cc->key, cc->key_size);
991 static int crypt_wipe_key(struct crypt_config *cc)
993 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
994 memset(&cc->key, 0, cc->key_size * sizeof(u8));
995 return crypto_ablkcipher_setkey(cc->tfm, cc->key, cc->key_size);
998 static void crypt_dtr(struct dm_target *ti)
1000 struct crypt_config *cc = ti->private;
1008 destroy_workqueue(cc->io_queue);
1009 if (cc->crypt_queue)
1010 destroy_workqueue(cc->crypt_queue);
1013 bioset_free(cc->bs);
1016 mempool_destroy(cc->page_pool);
1018 mempool_destroy(cc->req_pool);
1020 mempool_destroy(cc->io_pool);
1022 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1023 cc->iv_gen_ops->dtr(cc);
1025 if (cc->tfm && !IS_ERR(cc->tfm))
1026 crypto_free_ablkcipher(cc->tfm);
1029 dm_put_device(ti, cc->dev);
1032 kzfree(cc->cipher_string);
1034 /* Must zero key material before freeing */
1038 static int crypt_ctr_cipher(struct dm_target *ti,
1039 char *cipher_in, char *key)
1041 struct crypt_config *cc = ti->private;
1042 char *tmp, *cipher, *chainmode, *ivmode, *ivopts;
1043 char *cipher_api = NULL;
1046 /* Convert to crypto api definition? */
1047 if (strchr(cipher_in, '(')) {
1048 ti->error = "Bad cipher specification";
1052 cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
1053 if (!cc->cipher_string)
1057 * Legacy dm-crypt cipher specification
1058 * cipher-mode-iv:ivopts
1061 cipher = strsep(&tmp, "-");
1063 cc->cipher = kstrdup(cipher, GFP_KERNEL);
1067 chainmode = strsep(&tmp, "-");
1068 ivopts = strsep(&tmp, "-");
1069 ivmode = strsep(&ivopts, ":");
1072 DMWARN("Ignoring unexpected additional cipher options");
1075 * For compatibility with the original dm-crypt mapping format, if
1076 * only the cipher name is supplied, use cbc-plain.
1078 if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
1083 if (strcmp(chainmode, "ecb") && !ivmode) {
1084 ti->error = "IV mechanism required";
1088 cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
1092 ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
1093 "%s(%s)", chainmode, cipher);
1099 /* Allocate cipher */
1100 cc->tfm = crypto_alloc_ablkcipher(cipher_api, 0, 0);
1101 if (IS_ERR(cc->tfm)) {
1102 ret = PTR_ERR(cc->tfm);
1103 ti->error = "Error allocating crypto tfm";
1107 /* Initialize and set key */
1108 ret = crypt_set_key(cc, key);
1110 ti->error = "Error decoding and setting key";
1115 cc->iv_size = crypto_ablkcipher_ivsize(cc->tfm);
1117 /* at least a 64 bit sector number should fit in our buffer */
1118 cc->iv_size = max(cc->iv_size,
1119 (unsigned int)(sizeof(u64) / sizeof(u8)));
1121 DMWARN("Selected cipher does not support IVs");
1125 /* Choose ivmode, see comments at iv code. */
1127 cc->iv_gen_ops = NULL;
1128 else if (strcmp(ivmode, "plain") == 0)
1129 cc->iv_gen_ops = &crypt_iv_plain_ops;
1130 else if (strcmp(ivmode, "plain64") == 0)
1131 cc->iv_gen_ops = &crypt_iv_plain64_ops;
1132 else if (strcmp(ivmode, "essiv") == 0)
1133 cc->iv_gen_ops = &crypt_iv_essiv_ops;
1134 else if (strcmp(ivmode, "benbi") == 0)
1135 cc->iv_gen_ops = &crypt_iv_benbi_ops;
1136 else if (strcmp(ivmode, "null") == 0)
1137 cc->iv_gen_ops = &crypt_iv_null_ops;
1140 ti->error = "Invalid IV mode";
1145 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
1146 ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
1148 ti->error = "Error creating IV";
1153 /* Initialize IV (set keys for ESSIV etc) */
1154 if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
1155 ret = cc->iv_gen_ops->init(cc);
1157 ti->error = "Error initialising IV";
1168 ti->error = "Cannot allocate cipher strings";
1173 * Construct an encryption mapping:
1174 * <cipher> <key> <iv_offset> <dev_path> <start>
1176 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1178 struct crypt_config *cc;
1179 unsigned int key_size, opt_params;
1180 unsigned long long tmpll;
1182 struct dm_arg_set as;
1183 const char *opt_string;
1185 static struct dm_arg _args[] = {
1186 {0, 1, "Invalid number of feature args"},
1190 ti->error = "Not enough arguments";
1194 key_size = strlen(argv[1]) >> 1;
1196 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
1198 ti->error = "Cannot allocate encryption context";
1201 cc->key_size = key_size;
1204 ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
1209 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1211 ti->error = "Cannot allocate crypt io mempool";
1215 cc->dmreq_start = sizeof(struct ablkcipher_request);
1216 cc->dmreq_start += crypto_ablkcipher_reqsize(cc->tfm);
1217 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
1218 cc->dmreq_start += crypto_ablkcipher_alignmask(cc->tfm) &
1219 ~(crypto_tfm_ctx_alignment() - 1);
1221 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1222 sizeof(struct dm_crypt_request) + cc->iv_size);
1223 if (!cc->req_pool) {
1224 ti->error = "Cannot allocate crypt request mempool";
1229 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1230 if (!cc->page_pool) {
1231 ti->error = "Cannot allocate page mempool";
1235 cc->bs = bioset_create(MIN_IOS, 0);
1237 ti->error = "Cannot allocate crypt bioset";
1242 if (sscanf(argv[2], "%llu", &tmpll) != 1) {
1243 ti->error = "Invalid iv_offset sector";
1246 cc->iv_offset = tmpll;
1248 if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
1249 ti->error = "Device lookup failed";
1253 if (sscanf(argv[4], "%llu", &tmpll) != 1) {
1254 ti->error = "Invalid device sector";
1262 /* Optional parameters */
1267 ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1271 opt_string = dm_shift_arg(&as);
1273 if (opt_params == 1 && opt_string &&
1274 !strcasecmp(opt_string, "allow_discards"))
1275 ti->num_discard_requests = 1;
1276 else if (opt_params) {
1278 ti->error = "Invalid feature arguments";
1284 cc->io_queue = create_singlethread_workqueue("kcryptd_io");
1285 if (!cc->io_queue) {
1286 ti->error = "Couldn't create kcryptd io queue";
1290 cc->crypt_queue = create_singlethread_workqueue("kcryptd");
1291 if (!cc->crypt_queue) {
1292 ti->error = "Couldn't create kcryptd queue";
1296 ti->num_flush_requests = 1;
1297 ti->discard_zeroes_data_unsupported = 1;
1306 static int crypt_map(struct dm_target *ti, struct bio *bio,
1307 union map_info *map_context)
1309 struct dm_crypt_io *io;
1310 struct crypt_config *cc;
1313 * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues.
1314 * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight
1315 * - for REQ_DISCARD caller must use flush if IO ordering matters
1317 if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) {
1319 bio->bi_bdev = cc->dev->bdev;
1320 if (bio_sectors(bio))
1321 bio->bi_sector = cc->start + dm_target_offset(ti, bio->bi_sector);
1322 return DM_MAPIO_REMAPPED;
1325 io = crypt_io_alloc(ti, bio, dm_target_offset(ti, bio->bi_sector));
1327 if (bio_data_dir(io->base_bio) == READ)
1328 kcryptd_queue_io(io);
1330 kcryptd_queue_crypt(io);
1332 return DM_MAPIO_SUBMITTED;
1335 static int crypt_status(struct dm_target *ti, status_type_t type,
1336 char *result, unsigned int maxlen)
1338 struct crypt_config *cc = ti->private;
1339 unsigned int sz = 0;
1342 case STATUSTYPE_INFO:
1346 case STATUSTYPE_TABLE:
1347 DMEMIT("%s ", cc->cipher_string);
1349 if (cc->key_size > 0) {
1350 if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1353 crypt_encode_key(result + sz, cc->key, cc->key_size);
1354 sz += cc->key_size << 1;
1361 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1362 cc->dev->name, (unsigned long long)cc->start);
1364 if (ti->num_discard_requests)
1365 DMEMIT(" 1 allow_discards");
1372 static void crypt_postsuspend(struct dm_target *ti)
1374 struct crypt_config *cc = ti->private;
1376 set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1379 static int crypt_preresume(struct dm_target *ti)
1381 struct crypt_config *cc = ti->private;
1383 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1384 DMERR("aborting resume - crypt key is not set.");
1391 static void crypt_resume(struct dm_target *ti)
1393 struct crypt_config *cc = ti->private;
1395 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1398 /* Message interface
1402 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1404 struct crypt_config *cc = ti->private;
1410 if (!strcasecmp(argv[0], "key")) {
1411 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1412 DMWARN("not suspended during key manipulation.");
1415 if (argc == 3 && !strcasecmp(argv[1], "set")) {
1416 ret = crypt_set_key(cc, argv[2]);
1419 if (cc->iv_gen_ops && cc->iv_gen_ops->init)
1420 ret = cc->iv_gen_ops->init(cc);
1423 if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
1424 if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
1425 ret = cc->iv_gen_ops->wipe(cc);
1429 return crypt_wipe_key(cc);
1434 DMWARN("unrecognised message received.");
1438 static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1439 struct bio_vec *biovec, int max_size)
1441 struct crypt_config *cc = ti->private;
1442 struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1444 if (!q->merge_bvec_fn)
1447 bvm->bi_bdev = cc->dev->bdev;
1448 bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
1450 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1453 static int crypt_iterate_devices(struct dm_target *ti,
1454 iterate_devices_callout_fn fn, void *data)
1456 struct crypt_config *cc = ti->private;
1458 return fn(ti, cc->dev, cc->start, ti->len, data);
1461 static struct target_type crypt_target = {
1463 .version = {1, 8, 0},
1464 .module = THIS_MODULE,
1468 .status = crypt_status,
1469 .postsuspend = crypt_postsuspend,
1470 .preresume = crypt_preresume,
1471 .resume = crypt_resume,
1472 .message = crypt_message,
1473 .merge = crypt_merge,
1474 .iterate_devices = crypt_iterate_devices,
1477 static int __init dm_crypt_init(void)
1481 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1482 if (!_crypt_io_pool)
1485 r = dm_register_target(&crypt_target);
1487 DMERR("register failed %d", r);
1488 kmem_cache_destroy(_crypt_io_pool);
1494 static void __exit dm_crypt_exit(void)
1496 dm_unregister_target(&crypt_target);
1497 kmem_cache_destroy(_crypt_io_pool);
1500 module_init(dm_crypt_init);
1501 module_exit(dm_crypt_exit);
1503 MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1504 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1505 MODULE_LICENSE("GPL");