[ARM] pxa: Gumstix Verdex PCMCIA support
[linux-2.6/verdex.git] / drivers / md / dm-crypt.c
blobed1038164019a1d5935937037c6aae2bd429c666
1 /*
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.
7 */
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>
23 #include <asm/page.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;
36 struct bio *bio_in;
37 struct bio *bio_out;
38 unsigned int offset_in;
39 unsigned int offset_out;
40 unsigned int idx_in;
41 unsigned int idx_out;
42 sector_t sector;
43 atomic_t pending;
47 * per bio private data
49 struct dm_crypt_io {
50 struct dm_target *target;
51 struct bio *base_bio;
52 struct work_struct work;
54 struct convert_context ctx;
56 atomic_t pending;
57 int error;
58 sector_t sector;
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;
68 struct crypt_config;
70 struct crypt_iv_operations {
71 int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
72 const char *opts);
73 void (*dtr)(struct crypt_config *cc);
74 const char *(*status)(struct crypt_config *cc);
75 int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
79 * Crypt: maps a linear range of a block device
80 * and encrypts / decrypts at the same time.
82 enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
83 struct crypt_config {
84 struct dm_dev *dev;
85 sector_t start;
88 * pool for per bio private data, crypto requests and
89 * encryption requeusts/buffer pages
91 mempool_t *io_pool;
92 mempool_t *req_pool;
93 mempool_t *page_pool;
94 struct bio_set *bs;
96 struct workqueue_struct *io_queue;
97 struct workqueue_struct *crypt_queue;
100 * crypto related data
102 struct crypt_iv_operations *iv_gen_ops;
103 char *iv_mode;
104 union {
105 struct crypto_cipher *essiv_tfm;
106 int benbi_shift;
107 } iv_gen_private;
108 sector_t iv_offset;
109 unsigned int iv_size;
112 * Layout of each crypto request:
114 * struct ablkcipher_request
115 * context
116 * padding
117 * struct dm_crypt_request
118 * padding
119 * IV
121 * The padding is added so that dm_crypt_request and the IV are
122 * correctly aligned.
124 unsigned int dmreq_start;
125 struct ablkcipher_request *req;
127 char cipher[CRYPTO_MAX_ALG_NAME];
128 char chainmode[CRYPTO_MAX_ALG_NAME];
129 struct crypto_ablkcipher *tfm;
130 unsigned long flags;
131 unsigned int key_size;
132 u8 key[0];
135 #define MIN_IOS 16
136 #define MIN_POOL_PAGES 32
137 #define MIN_BIO_PAGES 8
139 static struct kmem_cache *_crypt_io_pool;
141 static void clone_init(struct dm_crypt_io *, struct bio *);
142 static void kcryptd_queue_crypt(struct dm_crypt_io *io);
145 * Different IV generation algorithms:
147 * plain: the initial vector is the 32-bit little-endian version of the sector
148 * number, padded with zeros if necessary.
150 * essiv: "encrypted sector|salt initial vector", the sector number is
151 * encrypted with the bulk cipher using a salt as key. The salt
152 * should be derived from the bulk cipher's key via hashing.
154 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
155 * (needed for LRW-32-AES and possible other narrow block modes)
157 * null: the initial vector is always zero. Provides compatibility with
158 * obsolete loop_fish2 devices. Do not use for new devices.
160 * plumb: unimplemented, see:
161 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
164 static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
166 memset(iv, 0, cc->iv_size);
167 *(u32 *)iv = cpu_to_le32(sector & 0xffffffff);
169 return 0;
172 static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
173 const char *opts)
175 struct crypto_cipher *essiv_tfm;
176 struct crypto_hash *hash_tfm;
177 struct hash_desc desc;
178 struct scatterlist sg;
179 unsigned int saltsize;
180 u8 *salt;
181 int err;
183 if (opts == NULL) {
184 ti->error = "Digest algorithm missing for ESSIV mode";
185 return -EINVAL;
188 /* Hash the cipher key with the given hash algorithm */
189 hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
190 if (IS_ERR(hash_tfm)) {
191 ti->error = "Error initializing ESSIV hash";
192 return PTR_ERR(hash_tfm);
195 saltsize = crypto_hash_digestsize(hash_tfm);
196 salt = kmalloc(saltsize, GFP_KERNEL);
197 if (salt == NULL) {
198 ti->error = "Error kmallocing salt storage in ESSIV";
199 crypto_free_hash(hash_tfm);
200 return -ENOMEM;
203 sg_init_one(&sg, cc->key, cc->key_size);
204 desc.tfm = hash_tfm;
205 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
206 err = crypto_hash_digest(&desc, &sg, cc->key_size, salt);
207 crypto_free_hash(hash_tfm);
209 if (err) {
210 ti->error = "Error calculating hash in ESSIV";
211 kfree(salt);
212 return err;
215 /* Setup the essiv_tfm with the given salt */
216 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
217 if (IS_ERR(essiv_tfm)) {
218 ti->error = "Error allocating crypto tfm for ESSIV";
219 kfree(salt);
220 return PTR_ERR(essiv_tfm);
222 if (crypto_cipher_blocksize(essiv_tfm) !=
223 crypto_ablkcipher_ivsize(cc->tfm)) {
224 ti->error = "Block size of ESSIV cipher does "
225 "not match IV size of block cipher";
226 crypto_free_cipher(essiv_tfm);
227 kfree(salt);
228 return -EINVAL;
230 err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
231 if (err) {
232 ti->error = "Failed to set key for ESSIV cipher";
233 crypto_free_cipher(essiv_tfm);
234 kfree(salt);
235 return err;
237 kfree(salt);
239 cc->iv_gen_private.essiv_tfm = essiv_tfm;
240 return 0;
243 static void crypt_iv_essiv_dtr(struct crypt_config *cc)
245 crypto_free_cipher(cc->iv_gen_private.essiv_tfm);
246 cc->iv_gen_private.essiv_tfm = NULL;
249 static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
251 memset(iv, 0, cc->iv_size);
252 *(u64 *)iv = cpu_to_le64(sector);
253 crypto_cipher_encrypt_one(cc->iv_gen_private.essiv_tfm, iv, iv);
254 return 0;
257 static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
258 const char *opts)
260 unsigned bs = crypto_ablkcipher_blocksize(cc->tfm);
261 int log = ilog2(bs);
263 /* we need to calculate how far we must shift the sector count
264 * to get the cipher block count, we use this shift in _gen */
266 if (1 << log != bs) {
267 ti->error = "cypher blocksize is not a power of 2";
268 return -EINVAL;
271 if (log > 9) {
272 ti->error = "cypher blocksize is > 512";
273 return -EINVAL;
276 cc->iv_gen_private.benbi_shift = 9 - log;
278 return 0;
281 static void crypt_iv_benbi_dtr(struct crypt_config *cc)
285 static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
287 __be64 val;
289 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
291 val = cpu_to_be64(((u64)sector << cc->iv_gen_private.benbi_shift) + 1);
292 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
294 return 0;
297 static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
299 memset(iv, 0, cc->iv_size);
301 return 0;
304 static struct crypt_iv_operations crypt_iv_plain_ops = {
305 .generator = crypt_iv_plain_gen
308 static struct crypt_iv_operations crypt_iv_essiv_ops = {
309 .ctr = crypt_iv_essiv_ctr,
310 .dtr = crypt_iv_essiv_dtr,
311 .generator = crypt_iv_essiv_gen
314 static struct crypt_iv_operations crypt_iv_benbi_ops = {
315 .ctr = crypt_iv_benbi_ctr,
316 .dtr = crypt_iv_benbi_dtr,
317 .generator = crypt_iv_benbi_gen
320 static struct crypt_iv_operations crypt_iv_null_ops = {
321 .generator = crypt_iv_null_gen
324 static void crypt_convert_init(struct crypt_config *cc,
325 struct convert_context *ctx,
326 struct bio *bio_out, struct bio *bio_in,
327 sector_t sector)
329 ctx->bio_in = bio_in;
330 ctx->bio_out = bio_out;
331 ctx->offset_in = 0;
332 ctx->offset_out = 0;
333 ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
334 ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
335 ctx->sector = sector + cc->iv_offset;
336 init_completion(&ctx->restart);
339 static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
340 struct ablkcipher_request *req)
342 return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
345 static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc,
346 struct dm_crypt_request *dmreq)
348 return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start);
351 static int crypt_convert_block(struct crypt_config *cc,
352 struct convert_context *ctx,
353 struct ablkcipher_request *req)
355 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
356 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
357 struct dm_crypt_request *dmreq;
358 u8 *iv;
359 int r = 0;
361 dmreq = dmreq_of_req(cc, req);
362 iv = (u8 *)ALIGN((unsigned long)(dmreq + 1),
363 crypto_ablkcipher_alignmask(cc->tfm) + 1);
365 dmreq->ctx = ctx;
366 sg_init_table(&dmreq->sg_in, 1);
367 sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
368 bv_in->bv_offset + ctx->offset_in);
370 sg_init_table(&dmreq->sg_out, 1);
371 sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
372 bv_out->bv_offset + ctx->offset_out);
374 ctx->offset_in += 1 << SECTOR_SHIFT;
375 if (ctx->offset_in >= bv_in->bv_len) {
376 ctx->offset_in = 0;
377 ctx->idx_in++;
380 ctx->offset_out += 1 << SECTOR_SHIFT;
381 if (ctx->offset_out >= bv_out->bv_len) {
382 ctx->offset_out = 0;
383 ctx->idx_out++;
386 if (cc->iv_gen_ops) {
387 r = cc->iv_gen_ops->generator(cc, iv, ctx->sector);
388 if (r < 0)
389 return r;
392 ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
393 1 << SECTOR_SHIFT, iv);
395 if (bio_data_dir(ctx->bio_in) == WRITE)
396 r = crypto_ablkcipher_encrypt(req);
397 else
398 r = crypto_ablkcipher_decrypt(req);
400 return r;
403 static void kcryptd_async_done(struct crypto_async_request *async_req,
404 int error);
405 static void crypt_alloc_req(struct crypt_config *cc,
406 struct convert_context *ctx)
408 if (!cc->req)
409 cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
410 ablkcipher_request_set_tfm(cc->req, cc->tfm);
411 ablkcipher_request_set_callback(cc->req, CRYPTO_TFM_REQ_MAY_BACKLOG |
412 CRYPTO_TFM_REQ_MAY_SLEEP,
413 kcryptd_async_done,
414 dmreq_of_req(cc, cc->req));
418 * Encrypt / decrypt data from one bio to another one (can be the same one)
420 static int crypt_convert(struct crypt_config *cc,
421 struct convert_context *ctx)
423 int r;
425 atomic_set(&ctx->pending, 1);
427 while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
428 ctx->idx_out < ctx->bio_out->bi_vcnt) {
430 crypt_alloc_req(cc, ctx);
432 atomic_inc(&ctx->pending);
434 r = crypt_convert_block(cc, ctx, cc->req);
436 switch (r) {
437 /* async */
438 case -EBUSY:
439 wait_for_completion(&ctx->restart);
440 INIT_COMPLETION(ctx->restart);
441 /* fall through*/
442 case -EINPROGRESS:
443 cc->req = NULL;
444 ctx->sector++;
445 continue;
447 /* sync */
448 case 0:
449 atomic_dec(&ctx->pending);
450 ctx->sector++;
451 cond_resched();
452 continue;
454 /* error */
455 default:
456 atomic_dec(&ctx->pending);
457 return r;
461 return 0;
464 static void dm_crypt_bio_destructor(struct bio *bio)
466 struct dm_crypt_io *io = bio->bi_private;
467 struct crypt_config *cc = io->target->private;
469 bio_free(bio, cc->bs);
473 * Generate a new unfragmented bio with the given size
474 * This should never violate the device limitations
475 * May return a smaller bio when running out of pages, indicated by
476 * *out_of_pages set to 1.
478 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
479 unsigned *out_of_pages)
481 struct crypt_config *cc = io->target->private;
482 struct bio *clone;
483 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
484 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
485 unsigned i, len;
486 struct page *page;
488 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
489 if (!clone)
490 return NULL;
492 clone_init(io, clone);
493 *out_of_pages = 0;
495 for (i = 0; i < nr_iovecs; i++) {
496 page = mempool_alloc(cc->page_pool, gfp_mask);
497 if (!page) {
498 *out_of_pages = 1;
499 break;
503 * if additional pages cannot be allocated without waiting,
504 * return a partially allocated bio, the caller will then try
505 * to allocate additional bios while submitting this partial bio
507 if (i == (MIN_BIO_PAGES - 1))
508 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
510 len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
512 if (!bio_add_page(clone, page, len, 0)) {
513 mempool_free(page, cc->page_pool);
514 break;
517 size -= len;
520 if (!clone->bi_size) {
521 bio_put(clone);
522 return NULL;
525 return clone;
528 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
530 unsigned int i;
531 struct bio_vec *bv;
533 for (i = 0; i < clone->bi_vcnt; i++) {
534 bv = bio_iovec_idx(clone, i);
535 BUG_ON(!bv->bv_page);
536 mempool_free(bv->bv_page, cc->page_pool);
537 bv->bv_page = NULL;
541 static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti,
542 struct bio *bio, sector_t sector)
544 struct crypt_config *cc = ti->private;
545 struct dm_crypt_io *io;
547 io = mempool_alloc(cc->io_pool, GFP_NOIO);
548 io->target = ti;
549 io->base_bio = bio;
550 io->sector = sector;
551 io->error = 0;
552 io->base_io = NULL;
553 atomic_set(&io->pending, 0);
555 return io;
558 static void crypt_inc_pending(struct dm_crypt_io *io)
560 atomic_inc(&io->pending);
564 * One of the bios was finished. Check for completion of
565 * the whole request and correctly clean up the buffer.
566 * If base_io is set, wait for the last fragment to complete.
568 static void crypt_dec_pending(struct dm_crypt_io *io)
570 struct crypt_config *cc = io->target->private;
571 struct bio *base_bio = io->base_bio;
572 struct dm_crypt_io *base_io = io->base_io;
573 int error = io->error;
575 if (!atomic_dec_and_test(&io->pending))
576 return;
578 mempool_free(io, cc->io_pool);
580 if (likely(!base_io))
581 bio_endio(base_bio, error);
582 else {
583 if (error && !base_io->error)
584 base_io->error = error;
585 crypt_dec_pending(base_io);
590 * kcryptd/kcryptd_io:
592 * Needed because it would be very unwise to do decryption in an
593 * interrupt context.
595 * kcryptd performs the actual encryption or decryption.
597 * kcryptd_io performs the IO submission.
599 * They must be separated as otherwise the final stages could be
600 * starved by new requests which can block in the first stages due
601 * to memory allocation.
603 static void crypt_endio(struct bio *clone, int error)
605 struct dm_crypt_io *io = clone->bi_private;
606 struct crypt_config *cc = io->target->private;
607 unsigned rw = bio_data_dir(clone);
609 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
610 error = -EIO;
613 * free the processed pages
615 if (rw == WRITE)
616 crypt_free_buffer_pages(cc, clone);
618 bio_put(clone);
620 if (rw == READ && !error) {
621 kcryptd_queue_crypt(io);
622 return;
625 if (unlikely(error))
626 io->error = error;
628 crypt_dec_pending(io);
631 static void clone_init(struct dm_crypt_io *io, struct bio *clone)
633 struct crypt_config *cc = io->target->private;
635 clone->bi_private = io;
636 clone->bi_end_io = crypt_endio;
637 clone->bi_bdev = cc->dev->bdev;
638 clone->bi_rw = io->base_bio->bi_rw;
639 clone->bi_destructor = dm_crypt_bio_destructor;
642 static void kcryptd_io_read(struct dm_crypt_io *io)
644 struct crypt_config *cc = io->target->private;
645 struct bio *base_bio = io->base_bio;
646 struct bio *clone;
648 crypt_inc_pending(io);
651 * The block layer might modify the bvec array, so always
652 * copy the required bvecs because we need the original
653 * one in order to decrypt the whole bio data *afterwards*.
655 clone = bio_alloc_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs);
656 if (unlikely(!clone)) {
657 io->error = -ENOMEM;
658 crypt_dec_pending(io);
659 return;
662 clone_init(io, clone);
663 clone->bi_idx = 0;
664 clone->bi_vcnt = bio_segments(base_bio);
665 clone->bi_size = base_bio->bi_size;
666 clone->bi_sector = cc->start + io->sector;
667 memcpy(clone->bi_io_vec, bio_iovec(base_bio),
668 sizeof(struct bio_vec) * clone->bi_vcnt);
670 generic_make_request(clone);
673 static void kcryptd_io_write(struct dm_crypt_io *io)
675 struct bio *clone = io->ctx.bio_out;
676 generic_make_request(clone);
679 static void kcryptd_io(struct work_struct *work)
681 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
683 if (bio_data_dir(io->base_bio) == READ)
684 kcryptd_io_read(io);
685 else
686 kcryptd_io_write(io);
689 static void kcryptd_queue_io(struct dm_crypt_io *io)
691 struct crypt_config *cc = io->target->private;
693 INIT_WORK(&io->work, kcryptd_io);
694 queue_work(cc->io_queue, &io->work);
697 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
698 int error, int async)
700 struct bio *clone = io->ctx.bio_out;
701 struct crypt_config *cc = io->target->private;
703 if (unlikely(error < 0)) {
704 crypt_free_buffer_pages(cc, clone);
705 bio_put(clone);
706 io->error = -EIO;
707 crypt_dec_pending(io);
708 return;
711 /* crypt_convert should have filled the clone bio */
712 BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
714 clone->bi_sector = cc->start + io->sector;
716 if (async)
717 kcryptd_queue_io(io);
718 else
719 generic_make_request(clone);
722 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
724 struct crypt_config *cc = io->target->private;
725 struct bio *clone;
726 struct dm_crypt_io *new_io;
727 int crypt_finished;
728 unsigned out_of_pages = 0;
729 unsigned remaining = io->base_bio->bi_size;
730 sector_t sector = io->sector;
731 int r;
734 * Prevent io from disappearing until this function completes.
736 crypt_inc_pending(io);
737 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
740 * The allocated buffers can be smaller than the whole bio,
741 * so repeat the whole process until all the data can be handled.
743 while (remaining) {
744 clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
745 if (unlikely(!clone)) {
746 io->error = -ENOMEM;
747 break;
750 io->ctx.bio_out = clone;
751 io->ctx.idx_out = 0;
753 remaining -= clone->bi_size;
754 sector += bio_sectors(clone);
756 crypt_inc_pending(io);
757 r = crypt_convert(cc, &io->ctx);
758 crypt_finished = atomic_dec_and_test(&io->ctx.pending);
760 /* Encryption was already finished, submit io now */
761 if (crypt_finished) {
762 kcryptd_crypt_write_io_submit(io, r, 0);
765 * If there was an error, do not try next fragments.
766 * For async, error is processed in async handler.
768 if (unlikely(r < 0))
769 break;
771 io->sector = sector;
775 * Out of memory -> run queues
776 * But don't wait if split was due to the io size restriction
778 if (unlikely(out_of_pages))
779 congestion_wait(BLK_RW_ASYNC, HZ/100);
782 * With async crypto it is unsafe to share the crypto context
783 * between fragments, so switch to a new dm_crypt_io structure.
785 if (unlikely(!crypt_finished && remaining)) {
786 new_io = crypt_io_alloc(io->target, io->base_bio,
787 sector);
788 crypt_inc_pending(new_io);
789 crypt_convert_init(cc, &new_io->ctx, NULL,
790 io->base_bio, sector);
791 new_io->ctx.idx_in = io->ctx.idx_in;
792 new_io->ctx.offset_in = io->ctx.offset_in;
795 * Fragments after the first use the base_io
796 * pending count.
798 if (!io->base_io)
799 new_io->base_io = io;
800 else {
801 new_io->base_io = io->base_io;
802 crypt_inc_pending(io->base_io);
803 crypt_dec_pending(io);
806 io = new_io;
810 crypt_dec_pending(io);
813 static void kcryptd_crypt_read_done(struct dm_crypt_io *io, int error)
815 if (unlikely(error < 0))
816 io->error = -EIO;
818 crypt_dec_pending(io);
821 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
823 struct crypt_config *cc = io->target->private;
824 int r = 0;
826 crypt_inc_pending(io);
828 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
829 io->sector);
831 r = crypt_convert(cc, &io->ctx);
833 if (atomic_dec_and_test(&io->ctx.pending))
834 kcryptd_crypt_read_done(io, r);
836 crypt_dec_pending(io);
839 static void kcryptd_async_done(struct crypto_async_request *async_req,
840 int error)
842 struct dm_crypt_request *dmreq = async_req->data;
843 struct convert_context *ctx = dmreq->ctx;
844 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
845 struct crypt_config *cc = io->target->private;
847 if (error == -EINPROGRESS) {
848 complete(&ctx->restart);
849 return;
852 mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool);
854 if (!atomic_dec_and_test(&ctx->pending))
855 return;
857 if (bio_data_dir(io->base_bio) == READ)
858 kcryptd_crypt_read_done(io, error);
859 else
860 kcryptd_crypt_write_io_submit(io, error, 1);
863 static void kcryptd_crypt(struct work_struct *work)
865 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
867 if (bio_data_dir(io->base_bio) == READ)
868 kcryptd_crypt_read_convert(io);
869 else
870 kcryptd_crypt_write_convert(io);
873 static void kcryptd_queue_crypt(struct dm_crypt_io *io)
875 struct crypt_config *cc = io->target->private;
877 INIT_WORK(&io->work, kcryptd_crypt);
878 queue_work(cc->crypt_queue, &io->work);
882 * Decode key from its hex representation
884 static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
886 char buffer[3];
887 char *endp;
888 unsigned int i;
890 buffer[2] = '\0';
892 for (i = 0; i < size; i++) {
893 buffer[0] = *hex++;
894 buffer[1] = *hex++;
896 key[i] = (u8)simple_strtoul(buffer, &endp, 16);
898 if (endp != &buffer[2])
899 return -EINVAL;
902 if (*hex != '\0')
903 return -EINVAL;
905 return 0;
909 * Encode key into its hex representation
911 static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
913 unsigned int i;
915 for (i = 0; i < size; i++) {
916 sprintf(hex, "%02x", *key);
917 hex += 2;
918 key++;
922 static int crypt_set_key(struct crypt_config *cc, char *key)
924 unsigned key_size = strlen(key) >> 1;
926 if (cc->key_size && cc->key_size != key_size)
927 return -EINVAL;
929 cc->key_size = key_size; /* initial settings */
931 if ((!key_size && strcmp(key, "-")) ||
932 (key_size && crypt_decode_key(cc->key, key, key_size) < 0))
933 return -EINVAL;
935 set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
937 return 0;
940 static int crypt_wipe_key(struct crypt_config *cc)
942 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
943 memset(&cc->key, 0, cc->key_size * sizeof(u8));
944 return 0;
948 * Construct an encryption mapping:
949 * <cipher> <key> <iv_offset> <dev_path> <start>
951 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
953 struct crypt_config *cc;
954 struct crypto_ablkcipher *tfm;
955 char *tmp;
956 char *cipher;
957 char *chainmode;
958 char *ivmode;
959 char *ivopts;
960 unsigned int key_size;
961 unsigned long long tmpll;
963 if (argc != 5) {
964 ti->error = "Not enough arguments";
965 return -EINVAL;
968 tmp = argv[0];
969 cipher = strsep(&tmp, "-");
970 chainmode = strsep(&tmp, "-");
971 ivopts = strsep(&tmp, "-");
972 ivmode = strsep(&ivopts, ":");
974 if (tmp)
975 DMWARN("Unexpected additional cipher options");
977 key_size = strlen(argv[1]) >> 1;
979 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
980 if (cc == NULL) {
981 ti->error =
982 "Cannot allocate transparent encryption context";
983 return -ENOMEM;
986 if (crypt_set_key(cc, argv[1])) {
987 ti->error = "Error decoding key";
988 goto bad_cipher;
991 /* Compatiblity mode for old dm-crypt cipher strings */
992 if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
993 chainmode = "cbc";
994 ivmode = "plain";
997 if (strcmp(chainmode, "ecb") && !ivmode) {
998 ti->error = "This chaining mode requires an IV mechanism";
999 goto bad_cipher;
1002 if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1003 chainmode, cipher) >= CRYPTO_MAX_ALG_NAME) {
1004 ti->error = "Chain mode + cipher name is too long";
1005 goto bad_cipher;
1008 tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
1009 if (IS_ERR(tfm)) {
1010 ti->error = "Error allocating crypto tfm";
1011 goto bad_cipher;
1014 strcpy(cc->cipher, cipher);
1015 strcpy(cc->chainmode, chainmode);
1016 cc->tfm = tfm;
1019 * Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi".
1020 * See comments at iv code
1023 if (ivmode == NULL)
1024 cc->iv_gen_ops = NULL;
1025 else if (strcmp(ivmode, "plain") == 0)
1026 cc->iv_gen_ops = &crypt_iv_plain_ops;
1027 else if (strcmp(ivmode, "essiv") == 0)
1028 cc->iv_gen_ops = &crypt_iv_essiv_ops;
1029 else if (strcmp(ivmode, "benbi") == 0)
1030 cc->iv_gen_ops = &crypt_iv_benbi_ops;
1031 else if (strcmp(ivmode, "null") == 0)
1032 cc->iv_gen_ops = &crypt_iv_null_ops;
1033 else {
1034 ti->error = "Invalid IV mode";
1035 goto bad_ivmode;
1038 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr &&
1039 cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
1040 goto bad_ivmode;
1042 cc->iv_size = crypto_ablkcipher_ivsize(tfm);
1043 if (cc->iv_size)
1044 /* at least a 64 bit sector number should fit in our buffer */
1045 cc->iv_size = max(cc->iv_size,
1046 (unsigned int)(sizeof(u64) / sizeof(u8)));
1047 else {
1048 if (cc->iv_gen_ops) {
1049 DMWARN("Selected cipher does not support IVs");
1050 if (cc->iv_gen_ops->dtr)
1051 cc->iv_gen_ops->dtr(cc);
1052 cc->iv_gen_ops = NULL;
1056 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1057 if (!cc->io_pool) {
1058 ti->error = "Cannot allocate crypt io mempool";
1059 goto bad_slab_pool;
1062 cc->dmreq_start = sizeof(struct ablkcipher_request);
1063 cc->dmreq_start += crypto_ablkcipher_reqsize(tfm);
1064 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
1065 cc->dmreq_start += crypto_ablkcipher_alignmask(tfm) &
1066 ~(crypto_tfm_ctx_alignment() - 1);
1068 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1069 sizeof(struct dm_crypt_request) + cc->iv_size);
1070 if (!cc->req_pool) {
1071 ti->error = "Cannot allocate crypt request mempool";
1072 goto bad_req_pool;
1074 cc->req = NULL;
1076 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1077 if (!cc->page_pool) {
1078 ti->error = "Cannot allocate page mempool";
1079 goto bad_page_pool;
1082 cc->bs = bioset_create(MIN_IOS, 0);
1083 if (!cc->bs) {
1084 ti->error = "Cannot allocate crypt bioset";
1085 goto bad_bs;
1088 if (crypto_ablkcipher_setkey(tfm, cc->key, key_size) < 0) {
1089 ti->error = "Error setting key";
1090 goto bad_device;
1093 if (sscanf(argv[2], "%llu", &tmpll) != 1) {
1094 ti->error = "Invalid iv_offset sector";
1095 goto bad_device;
1097 cc->iv_offset = tmpll;
1099 if (sscanf(argv[4], "%llu", &tmpll) != 1) {
1100 ti->error = "Invalid device sector";
1101 goto bad_device;
1103 cc->start = tmpll;
1105 if (dm_get_device(ti, argv[3], cc->start, ti->len,
1106 dm_table_get_mode(ti->table), &cc->dev)) {
1107 ti->error = "Device lookup failed";
1108 goto bad_device;
1111 if (ivmode && cc->iv_gen_ops) {
1112 if (ivopts)
1113 *(ivopts - 1) = ':';
1114 cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL);
1115 if (!cc->iv_mode) {
1116 ti->error = "Error kmallocing iv_mode string";
1117 goto bad_ivmode_string;
1119 strcpy(cc->iv_mode, ivmode);
1120 } else
1121 cc->iv_mode = NULL;
1123 cc->io_queue = create_singlethread_workqueue("kcryptd_io");
1124 if (!cc->io_queue) {
1125 ti->error = "Couldn't create kcryptd io queue";
1126 goto bad_io_queue;
1129 cc->crypt_queue = create_singlethread_workqueue("kcryptd");
1130 if (!cc->crypt_queue) {
1131 ti->error = "Couldn't create kcryptd queue";
1132 goto bad_crypt_queue;
1135 ti->num_flush_requests = 1;
1136 ti->private = cc;
1137 return 0;
1139 bad_crypt_queue:
1140 destroy_workqueue(cc->io_queue);
1141 bad_io_queue:
1142 kfree(cc->iv_mode);
1143 bad_ivmode_string:
1144 dm_put_device(ti, cc->dev);
1145 bad_device:
1146 bioset_free(cc->bs);
1147 bad_bs:
1148 mempool_destroy(cc->page_pool);
1149 bad_page_pool:
1150 mempool_destroy(cc->req_pool);
1151 bad_req_pool:
1152 mempool_destroy(cc->io_pool);
1153 bad_slab_pool:
1154 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1155 cc->iv_gen_ops->dtr(cc);
1156 bad_ivmode:
1157 crypto_free_ablkcipher(tfm);
1158 bad_cipher:
1159 /* Must zero key material before freeing */
1160 kzfree(cc);
1161 return -EINVAL;
1164 static void crypt_dtr(struct dm_target *ti)
1166 struct crypt_config *cc = (struct crypt_config *) ti->private;
1168 destroy_workqueue(cc->io_queue);
1169 destroy_workqueue(cc->crypt_queue);
1171 if (cc->req)
1172 mempool_free(cc->req, cc->req_pool);
1174 bioset_free(cc->bs);
1175 mempool_destroy(cc->page_pool);
1176 mempool_destroy(cc->req_pool);
1177 mempool_destroy(cc->io_pool);
1179 kfree(cc->iv_mode);
1180 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1181 cc->iv_gen_ops->dtr(cc);
1182 crypto_free_ablkcipher(cc->tfm);
1183 dm_put_device(ti, cc->dev);
1185 /* Must zero key material before freeing */
1186 kzfree(cc);
1189 static int crypt_map(struct dm_target *ti, struct bio *bio,
1190 union map_info *map_context)
1192 struct dm_crypt_io *io;
1193 struct crypt_config *cc;
1195 if (unlikely(bio_empty_barrier(bio))) {
1196 cc = ti->private;
1197 bio->bi_bdev = cc->dev->bdev;
1198 return DM_MAPIO_REMAPPED;
1201 io = crypt_io_alloc(ti, bio, bio->bi_sector - ti->begin);
1203 if (bio_data_dir(io->base_bio) == READ)
1204 kcryptd_queue_io(io);
1205 else
1206 kcryptd_queue_crypt(io);
1208 return DM_MAPIO_SUBMITTED;
1211 static int crypt_status(struct dm_target *ti, status_type_t type,
1212 char *result, unsigned int maxlen)
1214 struct crypt_config *cc = (struct crypt_config *) ti->private;
1215 unsigned int sz = 0;
1217 switch (type) {
1218 case STATUSTYPE_INFO:
1219 result[0] = '\0';
1220 break;
1222 case STATUSTYPE_TABLE:
1223 if (cc->iv_mode)
1224 DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode,
1225 cc->iv_mode);
1226 else
1227 DMEMIT("%s-%s ", cc->cipher, cc->chainmode);
1229 if (cc->key_size > 0) {
1230 if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1231 return -ENOMEM;
1233 crypt_encode_key(result + sz, cc->key, cc->key_size);
1234 sz += cc->key_size << 1;
1235 } else {
1236 if (sz >= maxlen)
1237 return -ENOMEM;
1238 result[sz++] = '-';
1241 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1242 cc->dev->name, (unsigned long long)cc->start);
1243 break;
1245 return 0;
1248 static void crypt_postsuspend(struct dm_target *ti)
1250 struct crypt_config *cc = ti->private;
1252 set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1255 static int crypt_preresume(struct dm_target *ti)
1257 struct crypt_config *cc = ti->private;
1259 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1260 DMERR("aborting resume - crypt key is not set.");
1261 return -EAGAIN;
1264 return 0;
1267 static void crypt_resume(struct dm_target *ti)
1269 struct crypt_config *cc = ti->private;
1271 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1274 /* Message interface
1275 * key set <key>
1276 * key wipe
1278 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1280 struct crypt_config *cc = ti->private;
1282 if (argc < 2)
1283 goto error;
1285 if (!strnicmp(argv[0], MESG_STR("key"))) {
1286 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1287 DMWARN("not suspended during key manipulation.");
1288 return -EINVAL;
1290 if (argc == 3 && !strnicmp(argv[1], MESG_STR("set")))
1291 return crypt_set_key(cc, argv[2]);
1292 if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe")))
1293 return crypt_wipe_key(cc);
1296 error:
1297 DMWARN("unrecognised message received.");
1298 return -EINVAL;
1301 static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1302 struct bio_vec *biovec, int max_size)
1304 struct crypt_config *cc = ti->private;
1305 struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1307 if (!q->merge_bvec_fn)
1308 return max_size;
1310 bvm->bi_bdev = cc->dev->bdev;
1311 bvm->bi_sector = cc->start + bvm->bi_sector - ti->begin;
1313 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1316 static int crypt_iterate_devices(struct dm_target *ti,
1317 iterate_devices_callout_fn fn, void *data)
1319 struct crypt_config *cc = ti->private;
1321 return fn(ti, cc->dev, cc->start, ti->len, data);
1324 static struct target_type crypt_target = {
1325 .name = "crypt",
1326 .version = {1, 7, 0},
1327 .module = THIS_MODULE,
1328 .ctr = crypt_ctr,
1329 .dtr = crypt_dtr,
1330 .map = crypt_map,
1331 .status = crypt_status,
1332 .postsuspend = crypt_postsuspend,
1333 .preresume = crypt_preresume,
1334 .resume = crypt_resume,
1335 .message = crypt_message,
1336 .merge = crypt_merge,
1337 .iterate_devices = crypt_iterate_devices,
1340 static int __init dm_crypt_init(void)
1342 int r;
1344 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1345 if (!_crypt_io_pool)
1346 return -ENOMEM;
1348 r = dm_register_target(&crypt_target);
1349 if (r < 0) {
1350 DMERR("register failed %d", r);
1351 kmem_cache_destroy(_crypt_io_pool);
1354 return r;
1357 static void __exit dm_crypt_exit(void)
1359 dm_unregister_target(&crypt_target);
1360 kmem_cache_destroy(_crypt_io_pool);
1363 module_init(dm_crypt_init);
1364 module_exit(dm_crypt_exit);
1366 MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1367 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1368 MODULE_LICENSE("GPL");