Merge branch 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[deliverable/linux.git] / drivers / md / dm-crypt.c
1 /*
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.
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 <linux/percpu.h>
22 #include <linux/atomic.h>
23 #include <linux/scatterlist.h>
24 #include <asm/page.h>
25 #include <asm/unaligned.h>
26 #include <crypto/hash.h>
27 #include <crypto/md5.h>
28 #include <crypto/algapi.h>
29
30 #include <linux/device-mapper.h>
31
32 #define DM_MSG_PREFIX "crypt"
33
34 /*
35 * context holding the current state of a multi-part conversion
36 */
37 struct convert_context {
38 struct completion restart;
39 struct bio *bio_in;
40 struct bio *bio_out;
41 unsigned int offset_in;
42 unsigned int offset_out;
43 unsigned int idx_in;
44 unsigned int idx_out;
45 sector_t cc_sector;
46 atomic_t cc_pending;
47 };
48
49 /*
50 * per bio private data
51 */
52 struct dm_crypt_io {
53 struct crypt_config *cc;
54 struct bio *base_bio;
55 struct work_struct work;
56
57 struct convert_context ctx;
58
59 atomic_t io_pending;
60 int error;
61 sector_t sector;
62 struct dm_crypt_io *base_io;
63 };
64
65 struct dm_crypt_request {
66 struct convert_context *ctx;
67 struct scatterlist sg_in;
68 struct scatterlist sg_out;
69 sector_t iv_sector;
70 };
71
72 struct crypt_config;
73
74 struct crypt_iv_operations {
75 int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
76 const char *opts);
77 void (*dtr)(struct crypt_config *cc);
78 int (*init)(struct crypt_config *cc);
79 int (*wipe)(struct crypt_config *cc);
80 int (*generator)(struct crypt_config *cc, u8 *iv,
81 struct dm_crypt_request *dmreq);
82 int (*post)(struct crypt_config *cc, u8 *iv,
83 struct dm_crypt_request *dmreq);
84 };
85
86 struct iv_essiv_private {
87 struct crypto_hash *hash_tfm;
88 u8 *salt;
89 };
90
91 struct iv_benbi_private {
92 int shift;
93 };
94
95 #define LMK_SEED_SIZE 64 /* hash + 0 */
96 struct iv_lmk_private {
97 struct crypto_shash *hash_tfm;
98 u8 *seed;
99 };
100
101 /*
102 * Crypt: maps a linear range of a block device
103 * and encrypts / decrypts at the same time.
104 */
105 enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
106
107 /*
108 * Duplicated per-CPU state for cipher.
109 */
110 struct crypt_cpu {
111 struct ablkcipher_request *req;
112 };
113
114 /*
115 * The fields in here must be read only after initialization,
116 * changing state should be in crypt_cpu.
117 */
118 struct crypt_config {
119 struct dm_dev *dev;
120 sector_t start;
121
122 /*
123 * pool for per bio private data, crypto requests and
124 * encryption requeusts/buffer pages
125 */
126 mempool_t *io_pool;
127 mempool_t *req_pool;
128 mempool_t *page_pool;
129 struct bio_set *bs;
130
131 struct workqueue_struct *io_queue;
132 struct workqueue_struct *crypt_queue;
133
134 char *cipher;
135 char *cipher_string;
136
137 struct crypt_iv_operations *iv_gen_ops;
138 union {
139 struct iv_essiv_private essiv;
140 struct iv_benbi_private benbi;
141 struct iv_lmk_private lmk;
142 } iv_gen_private;
143 sector_t iv_offset;
144 unsigned int iv_size;
145
146 /*
147 * Duplicated per cpu state. Access through
148 * per_cpu_ptr() only.
149 */
150 struct crypt_cpu __percpu *cpu;
151
152 /* ESSIV: struct crypto_cipher *essiv_tfm */
153 void *iv_private;
154 struct crypto_ablkcipher **tfms;
155 unsigned tfms_count;
156
157 /*
158 * Layout of each crypto request:
159 *
160 * struct ablkcipher_request
161 * context
162 * padding
163 * struct dm_crypt_request
164 * padding
165 * IV
166 *
167 * The padding is added so that dm_crypt_request and the IV are
168 * correctly aligned.
169 */
170 unsigned int dmreq_start;
171
172 unsigned long flags;
173 unsigned int key_size;
174 unsigned int key_parts;
175 u8 key[0];
176 };
177
178 #define MIN_IOS 16
179 #define MIN_POOL_PAGES 32
180
181 static struct kmem_cache *_crypt_io_pool;
182
183 static void clone_init(struct dm_crypt_io *, struct bio *);
184 static void kcryptd_queue_crypt(struct dm_crypt_io *io);
185 static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq);
186
187 static struct crypt_cpu *this_crypt_config(struct crypt_config *cc)
188 {
189 return this_cpu_ptr(cc->cpu);
190 }
191
192 /*
193 * Use this to access cipher attributes that are the same for each CPU.
194 */
195 static struct crypto_ablkcipher *any_tfm(struct crypt_config *cc)
196 {
197 return cc->tfms[0];
198 }
199
200 /*
201 * Different IV generation algorithms:
202 *
203 * plain: the initial vector is the 32-bit little-endian version of the sector
204 * number, padded with zeros if necessary.
205 *
206 * plain64: the initial vector is the 64-bit little-endian version of the sector
207 * number, padded with zeros if necessary.
208 *
209 * essiv: "encrypted sector|salt initial vector", the sector number is
210 * encrypted with the bulk cipher using a salt as key. The salt
211 * should be derived from the bulk cipher's key via hashing.
212 *
213 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
214 * (needed for LRW-32-AES and possible other narrow block modes)
215 *
216 * null: the initial vector is always zero. Provides compatibility with
217 * obsolete loop_fish2 devices. Do not use for new devices.
218 *
219 * lmk: Compatible implementation of the block chaining mode used
220 * by the Loop-AES block device encryption system
221 * designed by Jari Ruusu. See http://loop-aes.sourceforge.net/
222 * It operates on full 512 byte sectors and uses CBC
223 * with an IV derived from the sector number, the data and
224 * optionally extra IV seed.
225 * This means that after decryption the first block
226 * of sector must be tweaked according to decrypted data.
227 * Loop-AES can use three encryption schemes:
228 * version 1: is plain aes-cbc mode
229 * version 2: uses 64 multikey scheme with lmk IV generator
230 * version 3: the same as version 2 with additional IV seed
231 * (it uses 65 keys, last key is used as IV seed)
232 *
233 * plumb: unimplemented, see:
234 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
235 */
236
237 static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv,
238 struct dm_crypt_request *dmreq)
239 {
240 memset(iv, 0, cc->iv_size);
241 *(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff);
242
243 return 0;
244 }
245
246 static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
247 struct dm_crypt_request *dmreq)
248 {
249 memset(iv, 0, cc->iv_size);
250 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
251
252 return 0;
253 }
254
255 /* Initialise ESSIV - compute salt but no local memory allocations */
256 static int crypt_iv_essiv_init(struct crypt_config *cc)
257 {
258 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
259 struct hash_desc desc;
260 struct scatterlist sg;
261 struct crypto_cipher *essiv_tfm;
262 int err;
263
264 sg_init_one(&sg, cc->key, cc->key_size);
265 desc.tfm = essiv->hash_tfm;
266 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
267
268 err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt);
269 if (err)
270 return err;
271
272 essiv_tfm = cc->iv_private;
273
274 err = crypto_cipher_setkey(essiv_tfm, essiv->salt,
275 crypto_hash_digestsize(essiv->hash_tfm));
276 if (err)
277 return err;
278
279 return 0;
280 }
281
282 /* Wipe salt and reset key derived from volume key */
283 static int crypt_iv_essiv_wipe(struct crypt_config *cc)
284 {
285 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
286 unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm);
287 struct crypto_cipher *essiv_tfm;
288 int r, err = 0;
289
290 memset(essiv->salt, 0, salt_size);
291
292 essiv_tfm = cc->iv_private;
293 r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size);
294 if (r)
295 err = r;
296
297 return err;
298 }
299
300 /* Set up per cpu cipher state */
301 static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc,
302 struct dm_target *ti,
303 u8 *salt, unsigned saltsize)
304 {
305 struct crypto_cipher *essiv_tfm;
306 int err;
307
308 /* Setup the essiv_tfm with the given salt */
309 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
310 if (IS_ERR(essiv_tfm)) {
311 ti->error = "Error allocating crypto tfm for ESSIV";
312 return essiv_tfm;
313 }
314
315 if (crypto_cipher_blocksize(essiv_tfm) !=
316 crypto_ablkcipher_ivsize(any_tfm(cc))) {
317 ti->error = "Block size of ESSIV cipher does "
318 "not match IV size of block cipher";
319 crypto_free_cipher(essiv_tfm);
320 return ERR_PTR(-EINVAL);
321 }
322
323 err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
324 if (err) {
325 ti->error = "Failed to set key for ESSIV cipher";
326 crypto_free_cipher(essiv_tfm);
327 return ERR_PTR(err);
328 }
329
330 return essiv_tfm;
331 }
332
333 static void crypt_iv_essiv_dtr(struct crypt_config *cc)
334 {
335 struct crypto_cipher *essiv_tfm;
336 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
337
338 crypto_free_hash(essiv->hash_tfm);
339 essiv->hash_tfm = NULL;
340
341 kzfree(essiv->salt);
342 essiv->salt = NULL;
343
344 essiv_tfm = cc->iv_private;
345
346 if (essiv_tfm)
347 crypto_free_cipher(essiv_tfm);
348
349 cc->iv_private = NULL;
350 }
351
352 static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
353 const char *opts)
354 {
355 struct crypto_cipher *essiv_tfm = NULL;
356 struct crypto_hash *hash_tfm = NULL;
357 u8 *salt = NULL;
358 int err;
359
360 if (!opts) {
361 ti->error = "Digest algorithm missing for ESSIV mode";
362 return -EINVAL;
363 }
364
365 /* Allocate hash algorithm */
366 hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
367 if (IS_ERR(hash_tfm)) {
368 ti->error = "Error initializing ESSIV hash";
369 err = PTR_ERR(hash_tfm);
370 goto bad;
371 }
372
373 salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL);
374 if (!salt) {
375 ti->error = "Error kmallocing salt storage in ESSIV";
376 err = -ENOMEM;
377 goto bad;
378 }
379
380 cc->iv_gen_private.essiv.salt = salt;
381 cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
382
383 essiv_tfm = setup_essiv_cpu(cc, ti, salt,
384 crypto_hash_digestsize(hash_tfm));
385 if (IS_ERR(essiv_tfm)) {
386 crypt_iv_essiv_dtr(cc);
387 return PTR_ERR(essiv_tfm);
388 }
389 cc->iv_private = essiv_tfm;
390
391 return 0;
392
393 bad:
394 if (hash_tfm && !IS_ERR(hash_tfm))
395 crypto_free_hash(hash_tfm);
396 kfree(salt);
397 return err;
398 }
399
400 static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv,
401 struct dm_crypt_request *dmreq)
402 {
403 struct crypto_cipher *essiv_tfm = cc->iv_private;
404
405 memset(iv, 0, cc->iv_size);
406 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
407 crypto_cipher_encrypt_one(essiv_tfm, iv, iv);
408
409 return 0;
410 }
411
412 static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
413 const char *opts)
414 {
415 unsigned bs = crypto_ablkcipher_blocksize(any_tfm(cc));
416 int log = ilog2(bs);
417
418 /* we need to calculate how far we must shift the sector count
419 * to get the cipher block count, we use this shift in _gen */
420
421 if (1 << log != bs) {
422 ti->error = "cypher blocksize is not a power of 2";
423 return -EINVAL;
424 }
425
426 if (log > 9) {
427 ti->error = "cypher blocksize is > 512";
428 return -EINVAL;
429 }
430
431 cc->iv_gen_private.benbi.shift = 9 - log;
432
433 return 0;
434 }
435
436 static void crypt_iv_benbi_dtr(struct crypt_config *cc)
437 {
438 }
439
440 static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv,
441 struct dm_crypt_request *dmreq)
442 {
443 __be64 val;
444
445 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
446
447 val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1);
448 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
449
450 return 0;
451 }
452
453 static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv,
454 struct dm_crypt_request *dmreq)
455 {
456 memset(iv, 0, cc->iv_size);
457
458 return 0;
459 }
460
461 static void crypt_iv_lmk_dtr(struct crypt_config *cc)
462 {
463 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
464
465 if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm))
466 crypto_free_shash(lmk->hash_tfm);
467 lmk->hash_tfm = NULL;
468
469 kzfree(lmk->seed);
470 lmk->seed = NULL;
471 }
472
473 static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti,
474 const char *opts)
475 {
476 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
477
478 lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0);
479 if (IS_ERR(lmk->hash_tfm)) {
480 ti->error = "Error initializing LMK hash";
481 return PTR_ERR(lmk->hash_tfm);
482 }
483
484 /* No seed in LMK version 2 */
485 if (cc->key_parts == cc->tfms_count) {
486 lmk->seed = NULL;
487 return 0;
488 }
489
490 lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL);
491 if (!lmk->seed) {
492 crypt_iv_lmk_dtr(cc);
493 ti->error = "Error kmallocing seed storage in LMK";
494 return -ENOMEM;
495 }
496
497 return 0;
498 }
499
500 static int crypt_iv_lmk_init(struct crypt_config *cc)
501 {
502 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
503 int subkey_size = cc->key_size / cc->key_parts;
504
505 /* LMK seed is on the position of LMK_KEYS + 1 key */
506 if (lmk->seed)
507 memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size),
508 crypto_shash_digestsize(lmk->hash_tfm));
509
510 return 0;
511 }
512
513 static int crypt_iv_lmk_wipe(struct crypt_config *cc)
514 {
515 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
516
517 if (lmk->seed)
518 memset(lmk->seed, 0, LMK_SEED_SIZE);
519
520 return 0;
521 }
522
523 static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv,
524 struct dm_crypt_request *dmreq,
525 u8 *data)
526 {
527 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
528 struct {
529 struct shash_desc desc;
530 char ctx[crypto_shash_descsize(lmk->hash_tfm)];
531 } sdesc;
532 struct md5_state md5state;
533 u32 buf[4];
534 int i, r;
535
536 sdesc.desc.tfm = lmk->hash_tfm;
537 sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
538
539 r = crypto_shash_init(&sdesc.desc);
540 if (r)
541 return r;
542
543 if (lmk->seed) {
544 r = crypto_shash_update(&sdesc.desc, lmk->seed, LMK_SEED_SIZE);
545 if (r)
546 return r;
547 }
548
549 /* Sector is always 512B, block size 16, add data of blocks 1-31 */
550 r = crypto_shash_update(&sdesc.desc, data + 16, 16 * 31);
551 if (r)
552 return r;
553
554 /* Sector is cropped to 56 bits here */
555 buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF);
556 buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000);
557 buf[2] = cpu_to_le32(4024);
558 buf[3] = 0;
559 r = crypto_shash_update(&sdesc.desc, (u8 *)buf, sizeof(buf));
560 if (r)
561 return r;
562
563 /* No MD5 padding here */
564 r = crypto_shash_export(&sdesc.desc, &md5state);
565 if (r)
566 return r;
567
568 for (i = 0; i < MD5_HASH_WORDS; i++)
569 __cpu_to_le32s(&md5state.hash[i]);
570 memcpy(iv, &md5state.hash, cc->iv_size);
571
572 return 0;
573 }
574
575 static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv,
576 struct dm_crypt_request *dmreq)
577 {
578 u8 *src;
579 int r = 0;
580
581 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) {
582 src = kmap_atomic(sg_page(&dmreq->sg_in));
583 r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset);
584 kunmap_atomic(src);
585 } else
586 memset(iv, 0, cc->iv_size);
587
588 return r;
589 }
590
591 static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv,
592 struct dm_crypt_request *dmreq)
593 {
594 u8 *dst;
595 int r;
596
597 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE)
598 return 0;
599
600 dst = kmap_atomic(sg_page(&dmreq->sg_out));
601 r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset);
602
603 /* Tweak the first block of plaintext sector */
604 if (!r)
605 crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size);
606
607 kunmap_atomic(dst);
608 return r;
609 }
610
611 static struct crypt_iv_operations crypt_iv_plain_ops = {
612 .generator = crypt_iv_plain_gen
613 };
614
615 static struct crypt_iv_operations crypt_iv_plain64_ops = {
616 .generator = crypt_iv_plain64_gen
617 };
618
619 static struct crypt_iv_operations crypt_iv_essiv_ops = {
620 .ctr = crypt_iv_essiv_ctr,
621 .dtr = crypt_iv_essiv_dtr,
622 .init = crypt_iv_essiv_init,
623 .wipe = crypt_iv_essiv_wipe,
624 .generator = crypt_iv_essiv_gen
625 };
626
627 static struct crypt_iv_operations crypt_iv_benbi_ops = {
628 .ctr = crypt_iv_benbi_ctr,
629 .dtr = crypt_iv_benbi_dtr,
630 .generator = crypt_iv_benbi_gen
631 };
632
633 static struct crypt_iv_operations crypt_iv_null_ops = {
634 .generator = crypt_iv_null_gen
635 };
636
637 static struct crypt_iv_operations crypt_iv_lmk_ops = {
638 .ctr = crypt_iv_lmk_ctr,
639 .dtr = crypt_iv_lmk_dtr,
640 .init = crypt_iv_lmk_init,
641 .wipe = crypt_iv_lmk_wipe,
642 .generator = crypt_iv_lmk_gen,
643 .post = crypt_iv_lmk_post
644 };
645
646 static void crypt_convert_init(struct crypt_config *cc,
647 struct convert_context *ctx,
648 struct bio *bio_out, struct bio *bio_in,
649 sector_t sector)
650 {
651 ctx->bio_in = bio_in;
652 ctx->bio_out = bio_out;
653 ctx->offset_in = 0;
654 ctx->offset_out = 0;
655 ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
656 ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
657 ctx->cc_sector = sector + cc->iv_offset;
658 init_completion(&ctx->restart);
659 }
660
661 static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
662 struct ablkcipher_request *req)
663 {
664 return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
665 }
666
667 static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc,
668 struct dm_crypt_request *dmreq)
669 {
670 return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start);
671 }
672
673 static u8 *iv_of_dmreq(struct crypt_config *cc,
674 struct dm_crypt_request *dmreq)
675 {
676 return (u8 *)ALIGN((unsigned long)(dmreq + 1),
677 crypto_ablkcipher_alignmask(any_tfm(cc)) + 1);
678 }
679
680 static int crypt_convert_block(struct crypt_config *cc,
681 struct convert_context *ctx,
682 struct ablkcipher_request *req)
683 {
684 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
685 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
686 struct dm_crypt_request *dmreq;
687 u8 *iv;
688 int r;
689
690 dmreq = dmreq_of_req(cc, req);
691 iv = iv_of_dmreq(cc, dmreq);
692
693 dmreq->iv_sector = ctx->cc_sector;
694 dmreq->ctx = ctx;
695 sg_init_table(&dmreq->sg_in, 1);
696 sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
697 bv_in->bv_offset + ctx->offset_in);
698
699 sg_init_table(&dmreq->sg_out, 1);
700 sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
701 bv_out->bv_offset + ctx->offset_out);
702
703 ctx->offset_in += 1 << SECTOR_SHIFT;
704 if (ctx->offset_in >= bv_in->bv_len) {
705 ctx->offset_in = 0;
706 ctx->idx_in++;
707 }
708
709 ctx->offset_out += 1 << SECTOR_SHIFT;
710 if (ctx->offset_out >= bv_out->bv_len) {
711 ctx->offset_out = 0;
712 ctx->idx_out++;
713 }
714
715 if (cc->iv_gen_ops) {
716 r = cc->iv_gen_ops->generator(cc, iv, dmreq);
717 if (r < 0)
718 return r;
719 }
720
721 ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
722 1 << SECTOR_SHIFT, iv);
723
724 if (bio_data_dir(ctx->bio_in) == WRITE)
725 r = crypto_ablkcipher_encrypt(req);
726 else
727 r = crypto_ablkcipher_decrypt(req);
728
729 if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
730 r = cc->iv_gen_ops->post(cc, iv, dmreq);
731
732 return r;
733 }
734
735 static void kcryptd_async_done(struct crypto_async_request *async_req,
736 int error);
737
738 static void crypt_alloc_req(struct crypt_config *cc,
739 struct convert_context *ctx)
740 {
741 struct crypt_cpu *this_cc = this_crypt_config(cc);
742 unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1);
743
744 if (!this_cc->req)
745 this_cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
746
747 ablkcipher_request_set_tfm(this_cc->req, cc->tfms[key_index]);
748 ablkcipher_request_set_callback(this_cc->req,
749 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
750 kcryptd_async_done, dmreq_of_req(cc, this_cc->req));
751 }
752
753 /*
754 * Encrypt / decrypt data from one bio to another one (can be the same one)
755 */
756 static int crypt_convert(struct crypt_config *cc,
757 struct convert_context *ctx)
758 {
759 struct crypt_cpu *this_cc = this_crypt_config(cc);
760 int r;
761
762 atomic_set(&ctx->cc_pending, 1);
763
764 while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
765 ctx->idx_out < ctx->bio_out->bi_vcnt) {
766
767 crypt_alloc_req(cc, ctx);
768
769 atomic_inc(&ctx->cc_pending);
770
771 r = crypt_convert_block(cc, ctx, this_cc->req);
772
773 switch (r) {
774 /* async */
775 case -EBUSY:
776 wait_for_completion(&ctx->restart);
777 INIT_COMPLETION(ctx->restart);
778 /* fall through*/
779 case -EINPROGRESS:
780 this_cc->req = NULL;
781 ctx->cc_sector++;
782 continue;
783
784 /* sync */
785 case 0:
786 atomic_dec(&ctx->cc_pending);
787 ctx->cc_sector++;
788 cond_resched();
789 continue;
790
791 /* error */
792 default:
793 atomic_dec(&ctx->cc_pending);
794 return r;
795 }
796 }
797
798 return 0;
799 }
800
801 /*
802 * Generate a new unfragmented bio with the given size
803 * This should never violate the device limitations
804 * May return a smaller bio when running out of pages, indicated by
805 * *out_of_pages set to 1.
806 */
807 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
808 unsigned *out_of_pages)
809 {
810 struct crypt_config *cc = io->cc;
811 struct bio *clone;
812 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
813 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
814 unsigned i, len;
815 struct page *page;
816
817 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
818 if (!clone)
819 return NULL;
820
821 clone_init(io, clone);
822 *out_of_pages = 0;
823
824 for (i = 0; i < nr_iovecs; i++) {
825 page = mempool_alloc(cc->page_pool, gfp_mask);
826 if (!page) {
827 *out_of_pages = 1;
828 break;
829 }
830
831 /*
832 * If additional pages cannot be allocated without waiting,
833 * return a partially-allocated bio. The caller will then try
834 * to allocate more bios while submitting this partial bio.
835 */
836 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
837
838 len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
839
840 if (!bio_add_page(clone, page, len, 0)) {
841 mempool_free(page, cc->page_pool);
842 break;
843 }
844
845 size -= len;
846 }
847
848 if (!clone->bi_size) {
849 bio_put(clone);
850 return NULL;
851 }
852
853 return clone;
854 }
855
856 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
857 {
858 unsigned int i;
859 struct bio_vec *bv;
860
861 for (i = 0; i < clone->bi_vcnt; i++) {
862 bv = bio_iovec_idx(clone, i);
863 BUG_ON(!bv->bv_page);
864 mempool_free(bv->bv_page, cc->page_pool);
865 bv->bv_page = NULL;
866 }
867 }
868
869 static struct dm_crypt_io *crypt_io_alloc(struct crypt_config *cc,
870 struct bio *bio, sector_t sector)
871 {
872 struct dm_crypt_io *io;
873
874 io = mempool_alloc(cc->io_pool, GFP_NOIO);
875 io->cc = cc;
876 io->base_bio = bio;
877 io->sector = sector;
878 io->error = 0;
879 io->base_io = NULL;
880 atomic_set(&io->io_pending, 0);
881
882 return io;
883 }
884
885 static void crypt_inc_pending(struct dm_crypt_io *io)
886 {
887 atomic_inc(&io->io_pending);
888 }
889
890 /*
891 * One of the bios was finished. Check for completion of
892 * the whole request and correctly clean up the buffer.
893 * If base_io is set, wait for the last fragment to complete.
894 */
895 static void crypt_dec_pending(struct dm_crypt_io *io)
896 {
897 struct crypt_config *cc = io->cc;
898 struct bio *base_bio = io->base_bio;
899 struct dm_crypt_io *base_io = io->base_io;
900 int error = io->error;
901
902 if (!atomic_dec_and_test(&io->io_pending))
903 return;
904
905 mempool_free(io, cc->io_pool);
906
907 if (likely(!base_io))
908 bio_endio(base_bio, error);
909 else {
910 if (error && !base_io->error)
911 base_io->error = error;
912 crypt_dec_pending(base_io);
913 }
914 }
915
916 /*
917 * kcryptd/kcryptd_io:
918 *
919 * Needed because it would be very unwise to do decryption in an
920 * interrupt context.
921 *
922 * kcryptd performs the actual encryption or decryption.
923 *
924 * kcryptd_io performs the IO submission.
925 *
926 * They must be separated as otherwise the final stages could be
927 * starved by new requests which can block in the first stages due
928 * to memory allocation.
929 *
930 * The work is done per CPU global for all dm-crypt instances.
931 * They should not depend on each other and do not block.
932 */
933 static void crypt_endio(struct bio *clone, int error)
934 {
935 struct dm_crypt_io *io = clone->bi_private;
936 struct crypt_config *cc = io->cc;
937 unsigned rw = bio_data_dir(clone);
938
939 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
940 error = -EIO;
941
942 /*
943 * free the processed pages
944 */
945 if (rw == WRITE)
946 crypt_free_buffer_pages(cc, clone);
947
948 bio_put(clone);
949
950 if (rw == READ && !error) {
951 kcryptd_queue_crypt(io);
952 return;
953 }
954
955 if (unlikely(error))
956 io->error = error;
957
958 crypt_dec_pending(io);
959 }
960
961 static void clone_init(struct dm_crypt_io *io, struct bio *clone)
962 {
963 struct crypt_config *cc = io->cc;
964
965 clone->bi_private = io;
966 clone->bi_end_io = crypt_endio;
967 clone->bi_bdev = cc->dev->bdev;
968 clone->bi_rw = io->base_bio->bi_rw;
969 }
970
971 static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
972 {
973 struct crypt_config *cc = io->cc;
974 struct bio *base_bio = io->base_bio;
975 struct bio *clone;
976
977 /*
978 * The block layer might modify the bvec array, so always
979 * copy the required bvecs because we need the original
980 * one in order to decrypt the whole bio data *afterwards*.
981 */
982 clone = bio_clone_bioset(base_bio, gfp, cc->bs);
983 if (!clone)
984 return 1;
985
986 crypt_inc_pending(io);
987
988 clone_init(io, clone);
989 clone->bi_sector = cc->start + io->sector;
990
991 generic_make_request(clone);
992 return 0;
993 }
994
995 static void kcryptd_io_write(struct dm_crypt_io *io)
996 {
997 struct bio *clone = io->ctx.bio_out;
998 generic_make_request(clone);
999 }
1000
1001 static void kcryptd_io(struct work_struct *work)
1002 {
1003 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1004
1005 if (bio_data_dir(io->base_bio) == READ) {
1006 crypt_inc_pending(io);
1007 if (kcryptd_io_read(io, GFP_NOIO))
1008 io->error = -ENOMEM;
1009 crypt_dec_pending(io);
1010 } else
1011 kcryptd_io_write(io);
1012 }
1013
1014 static void kcryptd_queue_io(struct dm_crypt_io *io)
1015 {
1016 struct crypt_config *cc = io->cc;
1017
1018 INIT_WORK(&io->work, kcryptd_io);
1019 queue_work(cc->io_queue, &io->work);
1020 }
1021
1022 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
1023 {
1024 struct bio *clone = io->ctx.bio_out;
1025 struct crypt_config *cc = io->cc;
1026
1027 if (unlikely(io->error < 0)) {
1028 crypt_free_buffer_pages(cc, clone);
1029 bio_put(clone);
1030 crypt_dec_pending(io);
1031 return;
1032 }
1033
1034 /* crypt_convert should have filled the clone bio */
1035 BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
1036
1037 clone->bi_sector = cc->start + io->sector;
1038
1039 if (async)
1040 kcryptd_queue_io(io);
1041 else
1042 generic_make_request(clone);
1043 }
1044
1045 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
1046 {
1047 struct crypt_config *cc = io->cc;
1048 struct bio *clone;
1049 struct dm_crypt_io *new_io;
1050 int crypt_finished;
1051 unsigned out_of_pages = 0;
1052 unsigned remaining = io->base_bio->bi_size;
1053 sector_t sector = io->sector;
1054 int r;
1055
1056 /*
1057 * Prevent io from disappearing until this function completes.
1058 */
1059 crypt_inc_pending(io);
1060 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
1061
1062 /*
1063 * The allocated buffers can be smaller than the whole bio,
1064 * so repeat the whole process until all the data can be handled.
1065 */
1066 while (remaining) {
1067 clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
1068 if (unlikely(!clone)) {
1069 io->error = -ENOMEM;
1070 break;
1071 }
1072
1073 io->ctx.bio_out = clone;
1074 io->ctx.idx_out = 0;
1075
1076 remaining -= clone->bi_size;
1077 sector += bio_sectors(clone);
1078
1079 crypt_inc_pending(io);
1080
1081 r = crypt_convert(cc, &io->ctx);
1082 if (r < 0)
1083 io->error = -EIO;
1084
1085 crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending);
1086
1087 /* Encryption was already finished, submit io now */
1088 if (crypt_finished) {
1089 kcryptd_crypt_write_io_submit(io, 0);
1090
1091 /*
1092 * If there was an error, do not try next fragments.
1093 * For async, error is processed in async handler.
1094 */
1095 if (unlikely(r < 0))
1096 break;
1097
1098 io->sector = sector;
1099 }
1100
1101 /*
1102 * Out of memory -> run queues
1103 * But don't wait if split was due to the io size restriction
1104 */
1105 if (unlikely(out_of_pages))
1106 congestion_wait(BLK_RW_ASYNC, HZ/100);
1107
1108 /*
1109 * With async crypto it is unsafe to share the crypto context
1110 * between fragments, so switch to a new dm_crypt_io structure.
1111 */
1112 if (unlikely(!crypt_finished && remaining)) {
1113 new_io = crypt_io_alloc(io->cc, io->base_bio,
1114 sector);
1115 crypt_inc_pending(new_io);
1116 crypt_convert_init(cc, &new_io->ctx, NULL,
1117 io->base_bio, sector);
1118 new_io->ctx.idx_in = io->ctx.idx_in;
1119 new_io->ctx.offset_in = io->ctx.offset_in;
1120
1121 /*
1122 * Fragments after the first use the base_io
1123 * pending count.
1124 */
1125 if (!io->base_io)
1126 new_io->base_io = io;
1127 else {
1128 new_io->base_io = io->base_io;
1129 crypt_inc_pending(io->base_io);
1130 crypt_dec_pending(io);
1131 }
1132
1133 io = new_io;
1134 }
1135 }
1136
1137 crypt_dec_pending(io);
1138 }
1139
1140 static void kcryptd_crypt_read_done(struct dm_crypt_io *io)
1141 {
1142 crypt_dec_pending(io);
1143 }
1144
1145 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
1146 {
1147 struct crypt_config *cc = io->cc;
1148 int r = 0;
1149
1150 crypt_inc_pending(io);
1151
1152 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
1153 io->sector);
1154
1155 r = crypt_convert(cc, &io->ctx);
1156 if (r < 0)
1157 io->error = -EIO;
1158
1159 if (atomic_dec_and_test(&io->ctx.cc_pending))
1160 kcryptd_crypt_read_done(io);
1161
1162 crypt_dec_pending(io);
1163 }
1164
1165 static void kcryptd_async_done(struct crypto_async_request *async_req,
1166 int error)
1167 {
1168 struct dm_crypt_request *dmreq = async_req->data;
1169 struct convert_context *ctx = dmreq->ctx;
1170 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
1171 struct crypt_config *cc = io->cc;
1172
1173 if (error == -EINPROGRESS) {
1174 complete(&ctx->restart);
1175 return;
1176 }
1177
1178 if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
1179 error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
1180
1181 if (error < 0)
1182 io->error = -EIO;
1183
1184 mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool);
1185
1186 if (!atomic_dec_and_test(&ctx->cc_pending))
1187 return;
1188
1189 if (bio_data_dir(io->base_bio) == READ)
1190 kcryptd_crypt_read_done(io);
1191 else
1192 kcryptd_crypt_write_io_submit(io, 1);
1193 }
1194
1195 static void kcryptd_crypt(struct work_struct *work)
1196 {
1197 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1198
1199 if (bio_data_dir(io->base_bio) == READ)
1200 kcryptd_crypt_read_convert(io);
1201 else
1202 kcryptd_crypt_write_convert(io);
1203 }
1204
1205 static void kcryptd_queue_crypt(struct dm_crypt_io *io)
1206 {
1207 struct crypt_config *cc = io->cc;
1208
1209 INIT_WORK(&io->work, kcryptd_crypt);
1210 queue_work(cc->crypt_queue, &io->work);
1211 }
1212
1213 /*
1214 * Decode key from its hex representation
1215 */
1216 static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
1217 {
1218 char buffer[3];
1219 unsigned int i;
1220
1221 buffer[2] = '\0';
1222
1223 for (i = 0; i < size; i++) {
1224 buffer[0] = *hex++;
1225 buffer[1] = *hex++;
1226
1227 if (kstrtou8(buffer, 16, &key[i]))
1228 return -EINVAL;
1229 }
1230
1231 if (*hex != '\0')
1232 return -EINVAL;
1233
1234 return 0;
1235 }
1236
1237 /*
1238 * Encode key into its hex representation
1239 */
1240 static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
1241 {
1242 unsigned int i;
1243
1244 for (i = 0; i < size; i++) {
1245 sprintf(hex, "%02x", *key);
1246 hex += 2;
1247 key++;
1248 }
1249 }
1250
1251 static void crypt_free_tfms(struct crypt_config *cc)
1252 {
1253 unsigned i;
1254
1255 if (!cc->tfms)
1256 return;
1257
1258 for (i = 0; i < cc->tfms_count; i++)
1259 if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) {
1260 crypto_free_ablkcipher(cc->tfms[i]);
1261 cc->tfms[i] = NULL;
1262 }
1263
1264 kfree(cc->tfms);
1265 cc->tfms = NULL;
1266 }
1267
1268 static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode)
1269 {
1270 unsigned i;
1271 int err;
1272
1273 cc->tfms = kmalloc(cc->tfms_count * sizeof(struct crypto_ablkcipher *),
1274 GFP_KERNEL);
1275 if (!cc->tfms)
1276 return -ENOMEM;
1277
1278 for (i = 0; i < cc->tfms_count; i++) {
1279 cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0);
1280 if (IS_ERR(cc->tfms[i])) {
1281 err = PTR_ERR(cc->tfms[i]);
1282 crypt_free_tfms(cc);
1283 return err;
1284 }
1285 }
1286
1287 return 0;
1288 }
1289
1290 static int crypt_setkey_allcpus(struct crypt_config *cc)
1291 {
1292 unsigned subkey_size = cc->key_size >> ilog2(cc->tfms_count);
1293 int err = 0, i, r;
1294
1295 for (i = 0; i < cc->tfms_count; i++) {
1296 r = crypto_ablkcipher_setkey(cc->tfms[i],
1297 cc->key + (i * subkey_size),
1298 subkey_size);
1299 if (r)
1300 err = r;
1301 }
1302
1303 return err;
1304 }
1305
1306 static int crypt_set_key(struct crypt_config *cc, char *key)
1307 {
1308 int r = -EINVAL;
1309 int key_string_len = strlen(key);
1310
1311 /* The key size may not be changed. */
1312 if (cc->key_size != (key_string_len >> 1))
1313 goto out;
1314
1315 /* Hyphen (which gives a key_size of zero) means there is no key. */
1316 if (!cc->key_size && strcmp(key, "-"))
1317 goto out;
1318
1319 if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
1320 goto out;
1321
1322 set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1323
1324 r = crypt_setkey_allcpus(cc);
1325
1326 out:
1327 /* Hex key string not needed after here, so wipe it. */
1328 memset(key, '0', key_string_len);
1329
1330 return r;
1331 }
1332
1333 static int crypt_wipe_key(struct crypt_config *cc)
1334 {
1335 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1336 memset(&cc->key, 0, cc->key_size * sizeof(u8));
1337
1338 return crypt_setkey_allcpus(cc);
1339 }
1340
1341 static void crypt_dtr(struct dm_target *ti)
1342 {
1343 struct crypt_config *cc = ti->private;
1344 struct crypt_cpu *cpu_cc;
1345 int cpu;
1346
1347 ti->private = NULL;
1348
1349 if (!cc)
1350 return;
1351
1352 if (cc->io_queue)
1353 destroy_workqueue(cc->io_queue);
1354 if (cc->crypt_queue)
1355 destroy_workqueue(cc->crypt_queue);
1356
1357 if (cc->cpu)
1358 for_each_possible_cpu(cpu) {
1359 cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1360 if (cpu_cc->req)
1361 mempool_free(cpu_cc->req, cc->req_pool);
1362 }
1363
1364 crypt_free_tfms(cc);
1365
1366 if (cc->bs)
1367 bioset_free(cc->bs);
1368
1369 if (cc->page_pool)
1370 mempool_destroy(cc->page_pool);
1371 if (cc->req_pool)
1372 mempool_destroy(cc->req_pool);
1373 if (cc->io_pool)
1374 mempool_destroy(cc->io_pool);
1375
1376 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1377 cc->iv_gen_ops->dtr(cc);
1378
1379 if (cc->dev)
1380 dm_put_device(ti, cc->dev);
1381
1382 if (cc->cpu)
1383 free_percpu(cc->cpu);
1384
1385 kzfree(cc->cipher);
1386 kzfree(cc->cipher_string);
1387
1388 /* Must zero key material before freeing */
1389 kzfree(cc);
1390 }
1391
1392 static int crypt_ctr_cipher(struct dm_target *ti,
1393 char *cipher_in, char *key)
1394 {
1395 struct crypt_config *cc = ti->private;
1396 char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount;
1397 char *cipher_api = NULL;
1398 int ret = -EINVAL;
1399 char dummy;
1400
1401 /* Convert to crypto api definition? */
1402 if (strchr(cipher_in, '(')) {
1403 ti->error = "Bad cipher specification";
1404 return -EINVAL;
1405 }
1406
1407 cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
1408 if (!cc->cipher_string)
1409 goto bad_mem;
1410
1411 /*
1412 * Legacy dm-crypt cipher specification
1413 * cipher[:keycount]-mode-iv:ivopts
1414 */
1415 tmp = cipher_in;
1416 keycount = strsep(&tmp, "-");
1417 cipher = strsep(&keycount, ":");
1418
1419 if (!keycount)
1420 cc->tfms_count = 1;
1421 else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 ||
1422 !is_power_of_2(cc->tfms_count)) {
1423 ti->error = "Bad cipher key count specification";
1424 return -EINVAL;
1425 }
1426 cc->key_parts = cc->tfms_count;
1427
1428 cc->cipher = kstrdup(cipher, GFP_KERNEL);
1429 if (!cc->cipher)
1430 goto bad_mem;
1431
1432 chainmode = strsep(&tmp, "-");
1433 ivopts = strsep(&tmp, "-");
1434 ivmode = strsep(&ivopts, ":");
1435
1436 if (tmp)
1437 DMWARN("Ignoring unexpected additional cipher options");
1438
1439 cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)),
1440 __alignof__(struct crypt_cpu));
1441 if (!cc->cpu) {
1442 ti->error = "Cannot allocate per cpu state";
1443 goto bad_mem;
1444 }
1445
1446 /*
1447 * For compatibility with the original dm-crypt mapping format, if
1448 * only the cipher name is supplied, use cbc-plain.
1449 */
1450 if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
1451 chainmode = "cbc";
1452 ivmode = "plain";
1453 }
1454
1455 if (strcmp(chainmode, "ecb") && !ivmode) {
1456 ti->error = "IV mechanism required";
1457 return -EINVAL;
1458 }
1459
1460 cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
1461 if (!cipher_api)
1462 goto bad_mem;
1463
1464 ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
1465 "%s(%s)", chainmode, cipher);
1466 if (ret < 0) {
1467 kfree(cipher_api);
1468 goto bad_mem;
1469 }
1470
1471 /* Allocate cipher */
1472 ret = crypt_alloc_tfms(cc, cipher_api);
1473 if (ret < 0) {
1474 ti->error = "Error allocating crypto tfm";
1475 goto bad;
1476 }
1477
1478 /* Initialize and set key */
1479 ret = crypt_set_key(cc, key);
1480 if (ret < 0) {
1481 ti->error = "Error decoding and setting key";
1482 goto bad;
1483 }
1484
1485 /* Initialize IV */
1486 cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc));
1487 if (cc->iv_size)
1488 /* at least a 64 bit sector number should fit in our buffer */
1489 cc->iv_size = max(cc->iv_size,
1490 (unsigned int)(sizeof(u64) / sizeof(u8)));
1491 else if (ivmode) {
1492 DMWARN("Selected cipher does not support IVs");
1493 ivmode = NULL;
1494 }
1495
1496 /* Choose ivmode, see comments at iv code. */
1497 if (ivmode == NULL)
1498 cc->iv_gen_ops = NULL;
1499 else if (strcmp(ivmode, "plain") == 0)
1500 cc->iv_gen_ops = &crypt_iv_plain_ops;
1501 else if (strcmp(ivmode, "plain64") == 0)
1502 cc->iv_gen_ops = &crypt_iv_plain64_ops;
1503 else if (strcmp(ivmode, "essiv") == 0)
1504 cc->iv_gen_ops = &crypt_iv_essiv_ops;
1505 else if (strcmp(ivmode, "benbi") == 0)
1506 cc->iv_gen_ops = &crypt_iv_benbi_ops;
1507 else if (strcmp(ivmode, "null") == 0)
1508 cc->iv_gen_ops = &crypt_iv_null_ops;
1509 else if (strcmp(ivmode, "lmk") == 0) {
1510 cc->iv_gen_ops = &crypt_iv_lmk_ops;
1511 /* Version 2 and 3 is recognised according
1512 * to length of provided multi-key string.
1513 * If present (version 3), last key is used as IV seed.
1514 */
1515 if (cc->key_size % cc->key_parts)
1516 cc->key_parts++;
1517 } else {
1518 ret = -EINVAL;
1519 ti->error = "Invalid IV mode";
1520 goto bad;
1521 }
1522
1523 /* Allocate IV */
1524 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
1525 ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
1526 if (ret < 0) {
1527 ti->error = "Error creating IV";
1528 goto bad;
1529 }
1530 }
1531
1532 /* Initialize IV (set keys for ESSIV etc) */
1533 if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
1534 ret = cc->iv_gen_ops->init(cc);
1535 if (ret < 0) {
1536 ti->error = "Error initialising IV";
1537 goto bad;
1538 }
1539 }
1540
1541 ret = 0;
1542 bad:
1543 kfree(cipher_api);
1544 return ret;
1545
1546 bad_mem:
1547 ti->error = "Cannot allocate cipher strings";
1548 return -ENOMEM;
1549 }
1550
1551 /*
1552 * Construct an encryption mapping:
1553 * <cipher> <key> <iv_offset> <dev_path> <start>
1554 */
1555 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1556 {
1557 struct crypt_config *cc;
1558 unsigned int key_size, opt_params;
1559 unsigned long long tmpll;
1560 int ret;
1561 struct dm_arg_set as;
1562 const char *opt_string;
1563 char dummy;
1564
1565 static struct dm_arg _args[] = {
1566 {0, 1, "Invalid number of feature args"},
1567 };
1568
1569 if (argc < 5) {
1570 ti->error = "Not enough arguments";
1571 return -EINVAL;
1572 }
1573
1574 key_size = strlen(argv[1]) >> 1;
1575
1576 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
1577 if (!cc) {
1578 ti->error = "Cannot allocate encryption context";
1579 return -ENOMEM;
1580 }
1581 cc->key_size = key_size;
1582
1583 ti->private = cc;
1584 ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
1585 if (ret < 0)
1586 goto bad;
1587
1588 ret = -ENOMEM;
1589 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1590 if (!cc->io_pool) {
1591 ti->error = "Cannot allocate crypt io mempool";
1592 goto bad;
1593 }
1594
1595 cc->dmreq_start = sizeof(struct ablkcipher_request);
1596 cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc));
1597 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
1598 cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) &
1599 ~(crypto_tfm_ctx_alignment() - 1);
1600
1601 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1602 sizeof(struct dm_crypt_request) + cc->iv_size);
1603 if (!cc->req_pool) {
1604 ti->error = "Cannot allocate crypt request mempool";
1605 goto bad;
1606 }
1607
1608 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1609 if (!cc->page_pool) {
1610 ti->error = "Cannot allocate page mempool";
1611 goto bad;
1612 }
1613
1614 cc->bs = bioset_create(MIN_IOS, 0);
1615 if (!cc->bs) {
1616 ti->error = "Cannot allocate crypt bioset";
1617 goto bad;
1618 }
1619
1620 ret = -EINVAL;
1621 if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) {
1622 ti->error = "Invalid iv_offset sector";
1623 goto bad;
1624 }
1625 cc->iv_offset = tmpll;
1626
1627 if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
1628 ti->error = "Device lookup failed";
1629 goto bad;
1630 }
1631
1632 if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
1633 ti->error = "Invalid device sector";
1634 goto bad;
1635 }
1636 cc->start = tmpll;
1637
1638 argv += 5;
1639 argc -= 5;
1640
1641 /* Optional parameters */
1642 if (argc) {
1643 as.argc = argc;
1644 as.argv = argv;
1645
1646 ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1647 if (ret)
1648 goto bad;
1649
1650 opt_string = dm_shift_arg(&as);
1651
1652 if (opt_params == 1 && opt_string &&
1653 !strcasecmp(opt_string, "allow_discards"))
1654 ti->num_discard_requests = 1;
1655 else if (opt_params) {
1656 ret = -EINVAL;
1657 ti->error = "Invalid feature arguments";
1658 goto bad;
1659 }
1660 }
1661
1662 ret = -ENOMEM;
1663 cc->io_queue = alloc_workqueue("kcryptd_io",
1664 WQ_NON_REENTRANT|
1665 WQ_MEM_RECLAIM,
1666 1);
1667 if (!cc->io_queue) {
1668 ti->error = "Couldn't create kcryptd io queue";
1669 goto bad;
1670 }
1671
1672 cc->crypt_queue = alloc_workqueue("kcryptd",
1673 WQ_NON_REENTRANT|
1674 WQ_CPU_INTENSIVE|
1675 WQ_MEM_RECLAIM,
1676 1);
1677 if (!cc->crypt_queue) {
1678 ti->error = "Couldn't create kcryptd queue";
1679 goto bad;
1680 }
1681
1682 ti->num_flush_requests = 1;
1683 ti->discard_zeroes_data_unsupported = true;
1684
1685 return 0;
1686
1687 bad:
1688 crypt_dtr(ti);
1689 return ret;
1690 }
1691
1692 static int crypt_map(struct dm_target *ti, struct bio *bio)
1693 {
1694 struct dm_crypt_io *io;
1695 struct crypt_config *cc = ti->private;
1696
1697 /*
1698 * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues.
1699 * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight
1700 * - for REQ_DISCARD caller must use flush if IO ordering matters
1701 */
1702 if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) {
1703 bio->bi_bdev = cc->dev->bdev;
1704 if (bio_sectors(bio))
1705 bio->bi_sector = cc->start + dm_target_offset(ti, bio->bi_sector);
1706 return DM_MAPIO_REMAPPED;
1707 }
1708
1709 io = crypt_io_alloc(cc, bio, dm_target_offset(ti, bio->bi_sector));
1710
1711 if (bio_data_dir(io->base_bio) == READ) {
1712 if (kcryptd_io_read(io, GFP_NOWAIT))
1713 kcryptd_queue_io(io);
1714 } else
1715 kcryptd_queue_crypt(io);
1716
1717 return DM_MAPIO_SUBMITTED;
1718 }
1719
1720 static int crypt_status(struct dm_target *ti, status_type_t type,
1721 unsigned status_flags, char *result, unsigned maxlen)
1722 {
1723 struct crypt_config *cc = ti->private;
1724 unsigned int sz = 0;
1725
1726 switch (type) {
1727 case STATUSTYPE_INFO:
1728 result[0] = '\0';
1729 break;
1730
1731 case STATUSTYPE_TABLE:
1732 DMEMIT("%s ", cc->cipher_string);
1733
1734 if (cc->key_size > 0) {
1735 if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1736 return -ENOMEM;
1737
1738 crypt_encode_key(result + sz, cc->key, cc->key_size);
1739 sz += cc->key_size << 1;
1740 } else {
1741 if (sz >= maxlen)
1742 return -ENOMEM;
1743 result[sz++] = '-';
1744 }
1745
1746 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1747 cc->dev->name, (unsigned long long)cc->start);
1748
1749 if (ti->num_discard_requests)
1750 DMEMIT(" 1 allow_discards");
1751
1752 break;
1753 }
1754 return 0;
1755 }
1756
1757 static void crypt_postsuspend(struct dm_target *ti)
1758 {
1759 struct crypt_config *cc = ti->private;
1760
1761 set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1762 }
1763
1764 static int crypt_preresume(struct dm_target *ti)
1765 {
1766 struct crypt_config *cc = ti->private;
1767
1768 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1769 DMERR("aborting resume - crypt key is not set.");
1770 return -EAGAIN;
1771 }
1772
1773 return 0;
1774 }
1775
1776 static void crypt_resume(struct dm_target *ti)
1777 {
1778 struct crypt_config *cc = ti->private;
1779
1780 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1781 }
1782
1783 /* Message interface
1784 * key set <key>
1785 * key wipe
1786 */
1787 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1788 {
1789 struct crypt_config *cc = ti->private;
1790 int ret = -EINVAL;
1791
1792 if (argc < 2)
1793 goto error;
1794
1795 if (!strcasecmp(argv[0], "key")) {
1796 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1797 DMWARN("not suspended during key manipulation.");
1798 return -EINVAL;
1799 }
1800 if (argc == 3 && !strcasecmp(argv[1], "set")) {
1801 ret = crypt_set_key(cc, argv[2]);
1802 if (ret)
1803 return ret;
1804 if (cc->iv_gen_ops && cc->iv_gen_ops->init)
1805 ret = cc->iv_gen_ops->init(cc);
1806 return ret;
1807 }
1808 if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
1809 if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
1810 ret = cc->iv_gen_ops->wipe(cc);
1811 if (ret)
1812 return ret;
1813 }
1814 return crypt_wipe_key(cc);
1815 }
1816 }
1817
1818 error:
1819 DMWARN("unrecognised message received.");
1820 return -EINVAL;
1821 }
1822
1823 static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1824 struct bio_vec *biovec, int max_size)
1825 {
1826 struct crypt_config *cc = ti->private;
1827 struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1828
1829 if (!q->merge_bvec_fn)
1830 return max_size;
1831
1832 bvm->bi_bdev = cc->dev->bdev;
1833 bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
1834
1835 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1836 }
1837
1838 static int crypt_iterate_devices(struct dm_target *ti,
1839 iterate_devices_callout_fn fn, void *data)
1840 {
1841 struct crypt_config *cc = ti->private;
1842
1843 return fn(ti, cc->dev, cc->start, ti->len, data);
1844 }
1845
1846 static struct target_type crypt_target = {
1847 .name = "crypt",
1848 .version = {1, 12, 0},
1849 .module = THIS_MODULE,
1850 .ctr = crypt_ctr,
1851 .dtr = crypt_dtr,
1852 .map = crypt_map,
1853 .status = crypt_status,
1854 .postsuspend = crypt_postsuspend,
1855 .preresume = crypt_preresume,
1856 .resume = crypt_resume,
1857 .message = crypt_message,
1858 .merge = crypt_merge,
1859 .iterate_devices = crypt_iterate_devices,
1860 };
1861
1862 static int __init dm_crypt_init(void)
1863 {
1864 int r;
1865
1866 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1867 if (!_crypt_io_pool)
1868 return -ENOMEM;
1869
1870 r = dm_register_target(&crypt_target);
1871 if (r < 0) {
1872 DMERR("register failed %d", r);
1873 kmem_cache_destroy(_crypt_io_pool);
1874 }
1875
1876 return r;
1877 }
1878
1879 static void __exit dm_crypt_exit(void)
1880 {
1881 dm_unregister_target(&crypt_target);
1882 kmem_cache_destroy(_crypt_io_pool);
1883 }
1884
1885 module_init(dm_crypt_init);
1886 module_exit(dm_crypt_exit);
1887
1888 MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1889 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1890 MODULE_LICENSE("GPL");
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