dm exception store: use chunk_t for_areas
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / md / dm-crypt.c
... / ...
CommitLineData
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.
5 *
6 * This file is released under the GPL.
7 */
8
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>
25
26#include "dm.h"
27
28#define DM_MSG_PREFIX "crypt"
29#define MESG_STR(x) x, sizeof(x)
30
31/*
32 * context holding the current state of a multi-part conversion
33 */
34struct 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;
44};
45
46/*
47 * per bio private data
48 */
49struct dm_crypt_io {
50 struct dm_target *target;
51 struct bio *base_bio;
52 struct work_struct work;
53
54 struct convert_context ctx;
55
56 atomic_t pending;
57 int error;
58 sector_t sector;
59};
60
61struct dm_crypt_request {
62 struct scatterlist sg_in;
63 struct scatterlist sg_out;
64};
65
66struct crypt_config;
67
68struct crypt_iv_operations {
69 int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
70 const char *opts);
71 void (*dtr)(struct crypt_config *cc);
72 const char *(*status)(struct crypt_config *cc);
73 int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
74};
75
76/*
77 * Crypt: maps a linear range of a block device
78 * and encrypts / decrypts at the same time.
79 */
80enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
81struct crypt_config {
82 struct dm_dev *dev;
83 sector_t start;
84
85 /*
86 * pool for per bio private data, crypto requests and
87 * encryption requeusts/buffer pages
88 */
89 mempool_t *io_pool;
90 mempool_t *req_pool;
91 mempool_t *page_pool;
92 struct bio_set *bs;
93
94 struct workqueue_struct *io_queue;
95 struct workqueue_struct *crypt_queue;
96 wait_queue_head_t writeq;
97
98 /*
99 * crypto related data
100 */
101 struct crypt_iv_operations *iv_gen_ops;
102 char *iv_mode;
103 union {
104 struct crypto_cipher *essiv_tfm;
105 int benbi_shift;
106 } iv_gen_private;
107 sector_t iv_offset;
108 unsigned int iv_size;
109
110 /*
111 * Layout of each crypto request:
112 *
113 * struct ablkcipher_request
114 * context
115 * padding
116 * struct dm_crypt_request
117 * padding
118 * IV
119 *
120 * The padding is added so that dm_crypt_request and the IV are
121 * correctly aligned.
122 */
123 unsigned int dmreq_start;
124 struct ablkcipher_request *req;
125
126 char cipher[CRYPTO_MAX_ALG_NAME];
127 char chainmode[CRYPTO_MAX_ALG_NAME];
128 struct crypto_ablkcipher *tfm;
129 unsigned long flags;
130 unsigned int key_size;
131 u8 key[0];
132};
133
134#define MIN_IOS 16
135#define MIN_POOL_PAGES 32
136#define MIN_BIO_PAGES 8
137
138static struct kmem_cache *_crypt_io_pool;
139
140static void clone_init(struct dm_crypt_io *, struct bio *);
141static void kcryptd_queue_crypt(struct dm_crypt_io *io);
142
143/*
144 * Different IV generation algorithms:
145 *
146 * plain: the initial vector is the 32-bit little-endian version of the sector
147 * number, padded with zeros if necessary.
148 *
149 * essiv: "encrypted sector|salt initial vector", the sector number is
150 * encrypted with the bulk cipher using a salt as key. The salt
151 * should be derived from the bulk cipher's key via hashing.
152 *
153 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
154 * (needed for LRW-32-AES and possible other narrow block modes)
155 *
156 * null: the initial vector is always zero. Provides compatibility with
157 * obsolete loop_fish2 devices. Do not use for new devices.
158 *
159 * plumb: unimplemented, see:
160 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
161 */
162
163static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
164{
165 memset(iv, 0, cc->iv_size);
166 *(u32 *)iv = cpu_to_le32(sector & 0xffffffff);
167
168 return 0;
169}
170
171static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
172 const char *opts)
173{
174 struct crypto_cipher *essiv_tfm;
175 struct crypto_hash *hash_tfm;
176 struct hash_desc desc;
177 struct scatterlist sg;
178 unsigned int saltsize;
179 u8 *salt;
180 int err;
181
182 if (opts == NULL) {
183 ti->error = "Digest algorithm missing for ESSIV mode";
184 return -EINVAL;
185 }
186
187 /* Hash the cipher key with the given hash algorithm */
188 hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
189 if (IS_ERR(hash_tfm)) {
190 ti->error = "Error initializing ESSIV hash";
191 return PTR_ERR(hash_tfm);
192 }
193
194 saltsize = crypto_hash_digestsize(hash_tfm);
195 salt = kmalloc(saltsize, GFP_KERNEL);
196 if (salt == NULL) {
197 ti->error = "Error kmallocing salt storage in ESSIV";
198 crypto_free_hash(hash_tfm);
199 return -ENOMEM;
200 }
201
202 sg_init_one(&sg, cc->key, cc->key_size);
203 desc.tfm = hash_tfm;
204 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
205 err = crypto_hash_digest(&desc, &sg, cc->key_size, salt);
206 crypto_free_hash(hash_tfm);
207
208 if (err) {
209 ti->error = "Error calculating hash in ESSIV";
210 kfree(salt);
211 return err;
212 }
213
214 /* Setup the essiv_tfm with the given salt */
215 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
216 if (IS_ERR(essiv_tfm)) {
217 ti->error = "Error allocating crypto tfm for ESSIV";
218 kfree(salt);
219 return PTR_ERR(essiv_tfm);
220 }
221 if (crypto_cipher_blocksize(essiv_tfm) !=
222 crypto_ablkcipher_ivsize(cc->tfm)) {
223 ti->error = "Block size of ESSIV cipher does "
224 "not match IV size of block cipher";
225 crypto_free_cipher(essiv_tfm);
226 kfree(salt);
227 return -EINVAL;
228 }
229 err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
230 if (err) {
231 ti->error = "Failed to set key for ESSIV cipher";
232 crypto_free_cipher(essiv_tfm);
233 kfree(salt);
234 return err;
235 }
236 kfree(salt);
237
238 cc->iv_gen_private.essiv_tfm = essiv_tfm;
239 return 0;
240}
241
242static void crypt_iv_essiv_dtr(struct crypt_config *cc)
243{
244 crypto_free_cipher(cc->iv_gen_private.essiv_tfm);
245 cc->iv_gen_private.essiv_tfm = NULL;
246}
247
248static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
249{
250 memset(iv, 0, cc->iv_size);
251 *(u64 *)iv = cpu_to_le64(sector);
252 crypto_cipher_encrypt_one(cc->iv_gen_private.essiv_tfm, iv, iv);
253 return 0;
254}
255
256static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
257 const char *opts)
258{
259 unsigned bs = crypto_ablkcipher_blocksize(cc->tfm);
260 int log = ilog2(bs);
261
262 /* we need to calculate how far we must shift the sector count
263 * to get the cipher block count, we use this shift in _gen */
264
265 if (1 << log != bs) {
266 ti->error = "cypher blocksize is not a power of 2";
267 return -EINVAL;
268 }
269
270 if (log > 9) {
271 ti->error = "cypher blocksize is > 512";
272 return -EINVAL;
273 }
274
275 cc->iv_gen_private.benbi_shift = 9 - log;
276
277 return 0;
278}
279
280static void crypt_iv_benbi_dtr(struct crypt_config *cc)
281{
282}
283
284static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
285{
286 __be64 val;
287
288 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
289
290 val = cpu_to_be64(((u64)sector << cc->iv_gen_private.benbi_shift) + 1);
291 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
292
293 return 0;
294}
295
296static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
297{
298 memset(iv, 0, cc->iv_size);
299
300 return 0;
301}
302
303static struct crypt_iv_operations crypt_iv_plain_ops = {
304 .generator = crypt_iv_plain_gen
305};
306
307static struct crypt_iv_operations crypt_iv_essiv_ops = {
308 .ctr = crypt_iv_essiv_ctr,
309 .dtr = crypt_iv_essiv_dtr,
310 .generator = crypt_iv_essiv_gen
311};
312
313static struct crypt_iv_operations crypt_iv_benbi_ops = {
314 .ctr = crypt_iv_benbi_ctr,
315 .dtr = crypt_iv_benbi_dtr,
316 .generator = crypt_iv_benbi_gen
317};
318
319static struct crypt_iv_operations crypt_iv_null_ops = {
320 .generator = crypt_iv_null_gen
321};
322
323static void crypt_convert_init(struct crypt_config *cc,
324 struct convert_context *ctx,
325 struct bio *bio_out, struct bio *bio_in,
326 sector_t sector)
327{
328 ctx->bio_in = bio_in;
329 ctx->bio_out = bio_out;
330 ctx->offset_in = 0;
331 ctx->offset_out = 0;
332 ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
333 ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
334 ctx->sector = sector + cc->iv_offset;
335 init_completion(&ctx->restart);
336 atomic_set(&ctx->pending, 1);
337}
338
339static int crypt_convert_block(struct crypt_config *cc,
340 struct convert_context *ctx,
341 struct ablkcipher_request *req)
342{
343 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
344 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
345 struct dm_crypt_request *dmreq;
346 u8 *iv;
347 int r = 0;
348
349 dmreq = (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
350 iv = (u8 *)ALIGN((unsigned long)(dmreq + 1),
351 crypto_ablkcipher_alignmask(cc->tfm) + 1);
352
353 sg_init_table(&dmreq->sg_in, 1);
354 sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
355 bv_in->bv_offset + ctx->offset_in);
356
357 sg_init_table(&dmreq->sg_out, 1);
358 sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
359 bv_out->bv_offset + ctx->offset_out);
360
361 ctx->offset_in += 1 << SECTOR_SHIFT;
362 if (ctx->offset_in >= bv_in->bv_len) {
363 ctx->offset_in = 0;
364 ctx->idx_in++;
365 }
366
367 ctx->offset_out += 1 << SECTOR_SHIFT;
368 if (ctx->offset_out >= bv_out->bv_len) {
369 ctx->offset_out = 0;
370 ctx->idx_out++;
371 }
372
373 if (cc->iv_gen_ops) {
374 r = cc->iv_gen_ops->generator(cc, iv, ctx->sector);
375 if (r < 0)
376 return r;
377 }
378
379 ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
380 1 << SECTOR_SHIFT, iv);
381
382 if (bio_data_dir(ctx->bio_in) == WRITE)
383 r = crypto_ablkcipher_encrypt(req);
384 else
385 r = crypto_ablkcipher_decrypt(req);
386
387 return r;
388}
389
390static void kcryptd_async_done(struct crypto_async_request *async_req,
391 int error);
392static void crypt_alloc_req(struct crypt_config *cc,
393 struct convert_context *ctx)
394{
395 if (!cc->req)
396 cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
397 ablkcipher_request_set_tfm(cc->req, cc->tfm);
398 ablkcipher_request_set_callback(cc->req, CRYPTO_TFM_REQ_MAY_BACKLOG |
399 CRYPTO_TFM_REQ_MAY_SLEEP,
400 kcryptd_async_done, ctx);
401}
402
403/*
404 * Encrypt / decrypt data from one bio to another one (can be the same one)
405 */
406static int crypt_convert(struct crypt_config *cc,
407 struct convert_context *ctx)
408{
409 int r;
410
411 while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
412 ctx->idx_out < ctx->bio_out->bi_vcnt) {
413
414 crypt_alloc_req(cc, ctx);
415
416 atomic_inc(&ctx->pending);
417
418 r = crypt_convert_block(cc, ctx, cc->req);
419
420 switch (r) {
421 /* async */
422 case -EBUSY:
423 wait_for_completion(&ctx->restart);
424 INIT_COMPLETION(ctx->restart);
425 /* fall through*/
426 case -EINPROGRESS:
427 cc->req = NULL;
428 ctx->sector++;
429 continue;
430
431 /* sync */
432 case 0:
433 atomic_dec(&ctx->pending);
434 ctx->sector++;
435 cond_resched();
436 continue;
437
438 /* error */
439 default:
440 atomic_dec(&ctx->pending);
441 return r;
442 }
443 }
444
445 return 0;
446}
447
448static void dm_crypt_bio_destructor(struct bio *bio)
449{
450 struct dm_crypt_io *io = bio->bi_private;
451 struct crypt_config *cc = io->target->private;
452
453 bio_free(bio, cc->bs);
454}
455
456/*
457 * Generate a new unfragmented bio with the given size
458 * This should never violate the device limitations
459 * May return a smaller bio when running out of pages
460 */
461static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
462{
463 struct crypt_config *cc = io->target->private;
464 struct bio *clone;
465 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
466 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
467 unsigned i, len;
468 struct page *page;
469
470 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
471 if (!clone)
472 return NULL;
473
474 clone_init(io, clone);
475
476 for (i = 0; i < nr_iovecs; i++) {
477 page = mempool_alloc(cc->page_pool, gfp_mask);
478 if (!page)
479 break;
480
481 /*
482 * if additional pages cannot be allocated without waiting,
483 * return a partially allocated bio, the caller will then try
484 * to allocate additional bios while submitting this partial bio
485 */
486 if (i == (MIN_BIO_PAGES - 1))
487 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
488
489 len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
490
491 if (!bio_add_page(clone, page, len, 0)) {
492 mempool_free(page, cc->page_pool);
493 break;
494 }
495
496 size -= len;
497 }
498
499 if (!clone->bi_size) {
500 bio_put(clone);
501 return NULL;
502 }
503
504 return clone;
505}
506
507static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
508{
509 unsigned int i;
510 struct bio_vec *bv;
511
512 for (i = 0; i < clone->bi_vcnt; i++) {
513 bv = bio_iovec_idx(clone, i);
514 BUG_ON(!bv->bv_page);
515 mempool_free(bv->bv_page, cc->page_pool);
516 bv->bv_page = NULL;
517 }
518}
519
520/*
521 * One of the bios was finished. Check for completion of
522 * the whole request and correctly clean up the buffer.
523 */
524static void crypt_dec_pending(struct dm_crypt_io *io)
525{
526 struct crypt_config *cc = io->target->private;
527
528 if (!atomic_dec_and_test(&io->pending))
529 return;
530
531 bio_endio(io->base_bio, io->error);
532 mempool_free(io, cc->io_pool);
533}
534
535/*
536 * kcryptd/kcryptd_io:
537 *
538 * Needed because it would be very unwise to do decryption in an
539 * interrupt context.
540 *
541 * kcryptd performs the actual encryption or decryption.
542 *
543 * kcryptd_io performs the IO submission.
544 *
545 * They must be separated as otherwise the final stages could be
546 * starved by new requests which can block in the first stages due
547 * to memory allocation.
548 */
549static void crypt_endio(struct bio *clone, int error)
550{
551 struct dm_crypt_io *io = clone->bi_private;
552 struct crypt_config *cc = io->target->private;
553 unsigned rw = bio_data_dir(clone);
554
555 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
556 error = -EIO;
557
558 /*
559 * free the processed pages
560 */
561 if (rw == WRITE)
562 crypt_free_buffer_pages(cc, clone);
563
564 bio_put(clone);
565
566 if (rw == READ && !error) {
567 kcryptd_queue_crypt(io);
568 return;
569 }
570
571 if (unlikely(error))
572 io->error = error;
573
574 crypt_dec_pending(io);
575}
576
577static void clone_init(struct dm_crypt_io *io, struct bio *clone)
578{
579 struct crypt_config *cc = io->target->private;
580
581 clone->bi_private = io;
582 clone->bi_end_io = crypt_endio;
583 clone->bi_bdev = cc->dev->bdev;
584 clone->bi_rw = io->base_bio->bi_rw;
585 clone->bi_destructor = dm_crypt_bio_destructor;
586}
587
588static void kcryptd_io_read(struct dm_crypt_io *io)
589{
590 struct crypt_config *cc = io->target->private;
591 struct bio *base_bio = io->base_bio;
592 struct bio *clone;
593
594 atomic_inc(&io->pending);
595
596 /*
597 * The block layer might modify the bvec array, so always
598 * copy the required bvecs because we need the original
599 * one in order to decrypt the whole bio data *afterwards*.
600 */
601 clone = bio_alloc_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs);
602 if (unlikely(!clone)) {
603 io->error = -ENOMEM;
604 crypt_dec_pending(io);
605 return;
606 }
607
608 clone_init(io, clone);
609 clone->bi_idx = 0;
610 clone->bi_vcnt = bio_segments(base_bio);
611 clone->bi_size = base_bio->bi_size;
612 clone->bi_sector = cc->start + io->sector;
613 memcpy(clone->bi_io_vec, bio_iovec(base_bio),
614 sizeof(struct bio_vec) * clone->bi_vcnt);
615
616 generic_make_request(clone);
617}
618
619static void kcryptd_io_write(struct dm_crypt_io *io)
620{
621 struct bio *clone = io->ctx.bio_out;
622 struct crypt_config *cc = io->target->private;
623
624 generic_make_request(clone);
625 wake_up(&cc->writeq);
626}
627
628static void kcryptd_io(struct work_struct *work)
629{
630 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
631
632 if (bio_data_dir(io->base_bio) == READ)
633 kcryptd_io_read(io);
634 else
635 kcryptd_io_write(io);
636}
637
638static void kcryptd_queue_io(struct dm_crypt_io *io)
639{
640 struct crypt_config *cc = io->target->private;
641
642 INIT_WORK(&io->work, kcryptd_io);
643 queue_work(cc->io_queue, &io->work);
644}
645
646static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
647 int error, int async)
648{
649 struct bio *clone = io->ctx.bio_out;
650 struct crypt_config *cc = io->target->private;
651
652 if (unlikely(error < 0)) {
653 crypt_free_buffer_pages(cc, clone);
654 bio_put(clone);
655 io->error = -EIO;
656 return;
657 }
658
659 /* crypt_convert should have filled the clone bio */
660 BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
661
662 clone->bi_sector = cc->start + io->sector;
663 io->sector += bio_sectors(clone);
664
665 if (async)
666 kcryptd_queue_io(io);
667 else {
668 atomic_inc(&io->pending);
669 generic_make_request(clone);
670 }
671}
672
673static void kcryptd_crypt_write_convert_loop(struct dm_crypt_io *io)
674{
675 struct crypt_config *cc = io->target->private;
676 struct bio *clone;
677 unsigned remaining = io->base_bio->bi_size;
678 int r;
679
680 /*
681 * The allocated buffers can be smaller than the whole bio,
682 * so repeat the whole process until all the data can be handled.
683 */
684 while (remaining) {
685 clone = crypt_alloc_buffer(io, remaining);
686 if (unlikely(!clone)) {
687 io->error = -ENOMEM;
688 return;
689 }
690
691 io->ctx.bio_out = clone;
692 io->ctx.idx_out = 0;
693
694 remaining -= clone->bi_size;
695
696 r = crypt_convert(cc, &io->ctx);
697
698 if (atomic_dec_and_test(&io->ctx.pending)) {
699 /* processed, no running async crypto */
700 kcryptd_crypt_write_io_submit(io, r, 0);
701 if (unlikely(r < 0))
702 return;
703 } else
704 atomic_inc(&io->pending);
705
706 /* out of memory -> run queues */
707 if (unlikely(remaining)) {
708 /* wait for async crypto then reinitialize pending */
709 wait_event(cc->writeq, !atomic_read(&io->ctx.pending));
710 atomic_set(&io->ctx.pending, 1);
711 congestion_wait(WRITE, HZ/100);
712 }
713 }
714}
715
716static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
717{
718 struct crypt_config *cc = io->target->private;
719
720 /*
721 * Prevent io from disappearing until this function completes.
722 */
723 atomic_inc(&io->pending);
724
725 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, io->sector);
726 kcryptd_crypt_write_convert_loop(io);
727
728 crypt_dec_pending(io);
729}
730
731static void kcryptd_crypt_read_done(struct dm_crypt_io *io, int error)
732{
733 if (unlikely(error < 0))
734 io->error = -EIO;
735
736 crypt_dec_pending(io);
737}
738
739static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
740{
741 struct crypt_config *cc = io->target->private;
742 int r = 0;
743
744 atomic_inc(&io->pending);
745
746 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
747 io->sector);
748
749 r = crypt_convert(cc, &io->ctx);
750
751 if (atomic_dec_and_test(&io->ctx.pending))
752 kcryptd_crypt_read_done(io, r);
753
754 crypt_dec_pending(io);
755}
756
757static void kcryptd_async_done(struct crypto_async_request *async_req,
758 int error)
759{
760 struct convert_context *ctx = async_req->data;
761 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
762 struct crypt_config *cc = io->target->private;
763
764 if (error == -EINPROGRESS) {
765 complete(&ctx->restart);
766 return;
767 }
768
769 mempool_free(ablkcipher_request_cast(async_req), cc->req_pool);
770
771 if (!atomic_dec_and_test(&ctx->pending))
772 return;
773
774 if (bio_data_dir(io->base_bio) == READ)
775 kcryptd_crypt_read_done(io, error);
776 else
777 kcryptd_crypt_write_io_submit(io, error, 1);
778}
779
780static void kcryptd_crypt(struct work_struct *work)
781{
782 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
783
784 if (bio_data_dir(io->base_bio) == READ)
785 kcryptd_crypt_read_convert(io);
786 else
787 kcryptd_crypt_write_convert(io);
788}
789
790static void kcryptd_queue_crypt(struct dm_crypt_io *io)
791{
792 struct crypt_config *cc = io->target->private;
793
794 INIT_WORK(&io->work, kcryptd_crypt);
795 queue_work(cc->crypt_queue, &io->work);
796}
797
798/*
799 * Decode key from its hex representation
800 */
801static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
802{
803 char buffer[3];
804 char *endp;
805 unsigned int i;
806
807 buffer[2] = '\0';
808
809 for (i = 0; i < size; i++) {
810 buffer[0] = *hex++;
811 buffer[1] = *hex++;
812
813 key[i] = (u8)simple_strtoul(buffer, &endp, 16);
814
815 if (endp != &buffer[2])
816 return -EINVAL;
817 }
818
819 if (*hex != '\0')
820 return -EINVAL;
821
822 return 0;
823}
824
825/*
826 * Encode key into its hex representation
827 */
828static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
829{
830 unsigned int i;
831
832 for (i = 0; i < size; i++) {
833 sprintf(hex, "%02x", *key);
834 hex += 2;
835 key++;
836 }
837}
838
839static int crypt_set_key(struct crypt_config *cc, char *key)
840{
841 unsigned key_size = strlen(key) >> 1;
842
843 if (cc->key_size && cc->key_size != key_size)
844 return -EINVAL;
845
846 cc->key_size = key_size; /* initial settings */
847
848 if ((!key_size && strcmp(key, "-")) ||
849 (key_size && crypt_decode_key(cc->key, key, key_size) < 0))
850 return -EINVAL;
851
852 set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
853
854 return 0;
855}
856
857static int crypt_wipe_key(struct crypt_config *cc)
858{
859 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
860 memset(&cc->key, 0, cc->key_size * sizeof(u8));
861 return 0;
862}
863
864/*
865 * Construct an encryption mapping:
866 * <cipher> <key> <iv_offset> <dev_path> <start>
867 */
868static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
869{
870 struct crypt_config *cc;
871 struct crypto_ablkcipher *tfm;
872 char *tmp;
873 char *cipher;
874 char *chainmode;
875 char *ivmode;
876 char *ivopts;
877 unsigned int key_size;
878 unsigned long long tmpll;
879
880 if (argc != 5) {
881 ti->error = "Not enough arguments";
882 return -EINVAL;
883 }
884
885 tmp = argv[0];
886 cipher = strsep(&tmp, "-");
887 chainmode = strsep(&tmp, "-");
888 ivopts = strsep(&tmp, "-");
889 ivmode = strsep(&ivopts, ":");
890
891 if (tmp)
892 DMWARN("Unexpected additional cipher options");
893
894 key_size = strlen(argv[1]) >> 1;
895
896 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
897 if (cc == NULL) {
898 ti->error =
899 "Cannot allocate transparent encryption context";
900 return -ENOMEM;
901 }
902
903 if (crypt_set_key(cc, argv[1])) {
904 ti->error = "Error decoding key";
905 goto bad_cipher;
906 }
907
908 /* Compatiblity mode for old dm-crypt cipher strings */
909 if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
910 chainmode = "cbc";
911 ivmode = "plain";
912 }
913
914 if (strcmp(chainmode, "ecb") && !ivmode) {
915 ti->error = "This chaining mode requires an IV mechanism";
916 goto bad_cipher;
917 }
918
919 if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)",
920 chainmode, cipher) >= CRYPTO_MAX_ALG_NAME) {
921 ti->error = "Chain mode + cipher name is too long";
922 goto bad_cipher;
923 }
924
925 tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
926 if (IS_ERR(tfm)) {
927 ti->error = "Error allocating crypto tfm";
928 goto bad_cipher;
929 }
930
931 strcpy(cc->cipher, cipher);
932 strcpy(cc->chainmode, chainmode);
933 cc->tfm = tfm;
934
935 /*
936 * Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi".
937 * See comments at iv code
938 */
939
940 if (ivmode == NULL)
941 cc->iv_gen_ops = NULL;
942 else if (strcmp(ivmode, "plain") == 0)
943 cc->iv_gen_ops = &crypt_iv_plain_ops;
944 else if (strcmp(ivmode, "essiv") == 0)
945 cc->iv_gen_ops = &crypt_iv_essiv_ops;
946 else if (strcmp(ivmode, "benbi") == 0)
947 cc->iv_gen_ops = &crypt_iv_benbi_ops;
948 else if (strcmp(ivmode, "null") == 0)
949 cc->iv_gen_ops = &crypt_iv_null_ops;
950 else {
951 ti->error = "Invalid IV mode";
952 goto bad_ivmode;
953 }
954
955 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr &&
956 cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
957 goto bad_ivmode;
958
959 cc->iv_size = crypto_ablkcipher_ivsize(tfm);
960 if (cc->iv_size)
961 /* at least a 64 bit sector number should fit in our buffer */
962 cc->iv_size = max(cc->iv_size,
963 (unsigned int)(sizeof(u64) / sizeof(u8)));
964 else {
965 if (cc->iv_gen_ops) {
966 DMWARN("Selected cipher does not support IVs");
967 if (cc->iv_gen_ops->dtr)
968 cc->iv_gen_ops->dtr(cc);
969 cc->iv_gen_ops = NULL;
970 }
971 }
972
973 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
974 if (!cc->io_pool) {
975 ti->error = "Cannot allocate crypt io mempool";
976 goto bad_slab_pool;
977 }
978
979 cc->dmreq_start = sizeof(struct ablkcipher_request);
980 cc->dmreq_start += crypto_ablkcipher_reqsize(tfm);
981 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
982 cc->dmreq_start += crypto_ablkcipher_alignmask(tfm) &
983 ~(crypto_tfm_ctx_alignment() - 1);
984
985 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
986 sizeof(struct dm_crypt_request) + cc->iv_size);
987 if (!cc->req_pool) {
988 ti->error = "Cannot allocate crypt request mempool";
989 goto bad_req_pool;
990 }
991 cc->req = NULL;
992
993 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
994 if (!cc->page_pool) {
995 ti->error = "Cannot allocate page mempool";
996 goto bad_page_pool;
997 }
998
999 cc->bs = bioset_create(MIN_IOS, MIN_IOS);
1000 if (!cc->bs) {
1001 ti->error = "Cannot allocate crypt bioset";
1002 goto bad_bs;
1003 }
1004
1005 if (crypto_ablkcipher_setkey(tfm, cc->key, key_size) < 0) {
1006 ti->error = "Error setting key";
1007 goto bad_device;
1008 }
1009
1010 if (sscanf(argv[2], "%llu", &tmpll) != 1) {
1011 ti->error = "Invalid iv_offset sector";
1012 goto bad_device;
1013 }
1014 cc->iv_offset = tmpll;
1015
1016 if (sscanf(argv[4], "%llu", &tmpll) != 1) {
1017 ti->error = "Invalid device sector";
1018 goto bad_device;
1019 }
1020 cc->start = tmpll;
1021
1022 if (dm_get_device(ti, argv[3], cc->start, ti->len,
1023 dm_table_get_mode(ti->table), &cc->dev)) {
1024 ti->error = "Device lookup failed";
1025 goto bad_device;
1026 }
1027
1028 if (ivmode && cc->iv_gen_ops) {
1029 if (ivopts)
1030 *(ivopts - 1) = ':';
1031 cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL);
1032 if (!cc->iv_mode) {
1033 ti->error = "Error kmallocing iv_mode string";
1034 goto bad_ivmode_string;
1035 }
1036 strcpy(cc->iv_mode, ivmode);
1037 } else
1038 cc->iv_mode = NULL;
1039
1040 cc->io_queue = create_singlethread_workqueue("kcryptd_io");
1041 if (!cc->io_queue) {
1042 ti->error = "Couldn't create kcryptd io queue";
1043 goto bad_io_queue;
1044 }
1045
1046 cc->crypt_queue = create_singlethread_workqueue("kcryptd");
1047 if (!cc->crypt_queue) {
1048 ti->error = "Couldn't create kcryptd queue";
1049 goto bad_crypt_queue;
1050 }
1051
1052 init_waitqueue_head(&cc->writeq);
1053 ti->private = cc;
1054 return 0;
1055
1056bad_crypt_queue:
1057 destroy_workqueue(cc->io_queue);
1058bad_io_queue:
1059 kfree(cc->iv_mode);
1060bad_ivmode_string:
1061 dm_put_device(ti, cc->dev);
1062bad_device:
1063 bioset_free(cc->bs);
1064bad_bs:
1065 mempool_destroy(cc->page_pool);
1066bad_page_pool:
1067 mempool_destroy(cc->req_pool);
1068bad_req_pool:
1069 mempool_destroy(cc->io_pool);
1070bad_slab_pool:
1071 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1072 cc->iv_gen_ops->dtr(cc);
1073bad_ivmode:
1074 crypto_free_ablkcipher(tfm);
1075bad_cipher:
1076 /* Must zero key material before freeing */
1077 memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
1078 kfree(cc);
1079 return -EINVAL;
1080}
1081
1082static void crypt_dtr(struct dm_target *ti)
1083{
1084 struct crypt_config *cc = (struct crypt_config *) ti->private;
1085
1086 destroy_workqueue(cc->io_queue);
1087 destroy_workqueue(cc->crypt_queue);
1088
1089 if (cc->req)
1090 mempool_free(cc->req, cc->req_pool);
1091
1092 bioset_free(cc->bs);
1093 mempool_destroy(cc->page_pool);
1094 mempool_destroy(cc->req_pool);
1095 mempool_destroy(cc->io_pool);
1096
1097 kfree(cc->iv_mode);
1098 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1099 cc->iv_gen_ops->dtr(cc);
1100 crypto_free_ablkcipher(cc->tfm);
1101 dm_put_device(ti, cc->dev);
1102
1103 /* Must zero key material before freeing */
1104 memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
1105 kfree(cc);
1106}
1107
1108static int crypt_map(struct dm_target *ti, struct bio *bio,
1109 union map_info *map_context)
1110{
1111 struct crypt_config *cc = ti->private;
1112 struct dm_crypt_io *io;
1113
1114 io = mempool_alloc(cc->io_pool, GFP_NOIO);
1115 io->target = ti;
1116 io->base_bio = bio;
1117 io->sector = bio->bi_sector - ti->begin;
1118 io->error = 0;
1119 atomic_set(&io->pending, 0);
1120
1121 if (bio_data_dir(io->base_bio) == READ)
1122 kcryptd_queue_io(io);
1123 else
1124 kcryptd_queue_crypt(io);
1125
1126 return DM_MAPIO_SUBMITTED;
1127}
1128
1129static int crypt_status(struct dm_target *ti, status_type_t type,
1130 char *result, unsigned int maxlen)
1131{
1132 struct crypt_config *cc = (struct crypt_config *) ti->private;
1133 unsigned int sz = 0;
1134
1135 switch (type) {
1136 case STATUSTYPE_INFO:
1137 result[0] = '\0';
1138 break;
1139
1140 case STATUSTYPE_TABLE:
1141 if (cc->iv_mode)
1142 DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode,
1143 cc->iv_mode);
1144 else
1145 DMEMIT("%s-%s ", cc->cipher, cc->chainmode);
1146
1147 if (cc->key_size > 0) {
1148 if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1149 return -ENOMEM;
1150
1151 crypt_encode_key(result + sz, cc->key, cc->key_size);
1152 sz += cc->key_size << 1;
1153 } else {
1154 if (sz >= maxlen)
1155 return -ENOMEM;
1156 result[sz++] = '-';
1157 }
1158
1159 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1160 cc->dev->name, (unsigned long long)cc->start);
1161 break;
1162 }
1163 return 0;
1164}
1165
1166static void crypt_postsuspend(struct dm_target *ti)
1167{
1168 struct crypt_config *cc = ti->private;
1169
1170 set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1171}
1172
1173static int crypt_preresume(struct dm_target *ti)
1174{
1175 struct crypt_config *cc = ti->private;
1176
1177 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1178 DMERR("aborting resume - crypt key is not set.");
1179 return -EAGAIN;
1180 }
1181
1182 return 0;
1183}
1184
1185static void crypt_resume(struct dm_target *ti)
1186{
1187 struct crypt_config *cc = ti->private;
1188
1189 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1190}
1191
1192/* Message interface
1193 * key set <key>
1194 * key wipe
1195 */
1196static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1197{
1198 struct crypt_config *cc = ti->private;
1199
1200 if (argc < 2)
1201 goto error;
1202
1203 if (!strnicmp(argv[0], MESG_STR("key"))) {
1204 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1205 DMWARN("not suspended during key manipulation.");
1206 return -EINVAL;
1207 }
1208 if (argc == 3 && !strnicmp(argv[1], MESG_STR("set")))
1209 return crypt_set_key(cc, argv[2]);
1210 if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe")))
1211 return crypt_wipe_key(cc);
1212 }
1213
1214error:
1215 DMWARN("unrecognised message received.");
1216 return -EINVAL;
1217}
1218
1219static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1220 struct bio_vec *biovec, int max_size)
1221{
1222 struct crypt_config *cc = ti->private;
1223 struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1224
1225 if (!q->merge_bvec_fn)
1226 return max_size;
1227
1228 bvm->bi_bdev = cc->dev->bdev;
1229 bvm->bi_sector = cc->start + bvm->bi_sector - ti->begin;
1230
1231 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1232}
1233
1234static struct target_type crypt_target = {
1235 .name = "crypt",
1236 .version= {1, 6, 0},
1237 .module = THIS_MODULE,
1238 .ctr = crypt_ctr,
1239 .dtr = crypt_dtr,
1240 .map = crypt_map,
1241 .status = crypt_status,
1242 .postsuspend = crypt_postsuspend,
1243 .preresume = crypt_preresume,
1244 .resume = crypt_resume,
1245 .message = crypt_message,
1246 .merge = crypt_merge,
1247};
1248
1249static int __init dm_crypt_init(void)
1250{
1251 int r;
1252
1253 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1254 if (!_crypt_io_pool)
1255 return -ENOMEM;
1256
1257 r = dm_register_target(&crypt_target);
1258 if (r < 0) {
1259 DMERR("register failed %d", r);
1260 kmem_cache_destroy(_crypt_io_pool);
1261 }
1262
1263 return r;
1264}
1265
1266static void __exit dm_crypt_exit(void)
1267{
1268 int r = dm_unregister_target(&crypt_target);
1269
1270 if (r < 0)
1271 DMERR("unregister failed %d", r);
1272
1273 kmem_cache_destroy(_crypt_io_pool);
1274}
1275
1276module_init(dm_crypt_init);
1277module_exit(dm_crypt_exit);
1278
1279MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1280MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1281MODULE_LICENSE("GPL");