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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 */
37struct 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 sector;
46 atomic_t pending;
47};
48
49/*
50 * per bio private data
51 */
52struct dm_crypt_io {
53 struct dm_target *target;
54 struct bio *base_bio;
55 struct work_struct work;
56
57 struct convert_context ctx;
58
59 atomic_t pending;
60 int error;
61 sector_t sector;
62 struct dm_crypt_io *base_io;
63};
64
65struct 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
72struct crypt_config;
73
74struct 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
86struct iv_essiv_private {
87 struct crypto_hash *hash_tfm;
88 u8 *salt;
89};
90
91struct iv_benbi_private {
92 int shift;
93};
94
95#define LMK_SEED_SIZE 64 /* hash + 0 */
96struct 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 */
105enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
106
107/*
108 * Duplicated per-CPU state for cipher.
109 */
110struct crypt_cpu {
111 struct ablkcipher_request *req;
112 /* ESSIV: struct crypto_cipher *essiv_tfm */
113 void *iv_private;
114 struct crypto_ablkcipher *tfms[0];
115};
116
117/*
118 * The fields in here must be read only after initialization,
119 * changing state should be in crypt_cpu.
120 */
121struct crypt_config {
122 struct dm_dev *dev;
123 sector_t start;
124
125 /*
126 * pool for per bio private data, crypto requests and
127 * encryption requeusts/buffer pages
128 */
129 mempool_t *io_pool;
130 mempool_t *req_pool;
131 mempool_t *page_pool;
132 struct bio_set *bs;
133
134 struct workqueue_struct *io_queue;
135 struct workqueue_struct *crypt_queue;
136
137 char *cipher;
138 char *cipher_string;
139
140 struct crypt_iv_operations *iv_gen_ops;
141 union {
142 struct iv_essiv_private essiv;
143 struct iv_benbi_private benbi;
144 struct iv_lmk_private lmk;
145 } iv_gen_private;
146 sector_t iv_offset;
147 unsigned int iv_size;
148
149 /*
150 * Duplicated per cpu state. Access through
151 * per_cpu_ptr() only.
152 */
153 struct crypt_cpu __percpu *cpu;
154 unsigned tfms_count;
155
156 /*
157 * Layout of each crypto request:
158 *
159 * struct ablkcipher_request
160 * context
161 * padding
162 * struct dm_crypt_request
163 * padding
164 * IV
165 *
166 * The padding is added so that dm_crypt_request and the IV are
167 * correctly aligned.
168 */
169 unsigned int dmreq_start;
170
171 unsigned long flags;
172 unsigned int key_size;
173 unsigned int key_parts;
174 u8 key[0];
175};
176
177#define MIN_IOS 16
178#define MIN_POOL_PAGES 32
179
180static struct kmem_cache *_crypt_io_pool;
181
182static void clone_init(struct dm_crypt_io *, struct bio *);
183static void kcryptd_queue_crypt(struct dm_crypt_io *io);
184static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq);
185
186static struct crypt_cpu *this_crypt_config(struct crypt_config *cc)
187{
188 return this_cpu_ptr(cc->cpu);
189}
190
191/*
192 * Use this to access cipher attributes that are the same for each CPU.
193 */
194static struct crypto_ablkcipher *any_tfm(struct crypt_config *cc)
195{
196 return __this_cpu_ptr(cc->cpu)->tfms[0];
197}
198
199/*
200 * Different IV generation algorithms:
201 *
202 * plain: the initial vector is the 32-bit little-endian version of the sector
203 * number, padded with zeros if necessary.
204 *
205 * plain64: the initial vector is the 64-bit little-endian version of the sector
206 * number, padded with zeros if necessary.
207 *
208 * essiv: "encrypted sector|salt initial vector", the sector number is
209 * encrypted with the bulk cipher using a salt as key. The salt
210 * should be derived from the bulk cipher's key via hashing.
211 *
212 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
213 * (needed for LRW-32-AES and possible other narrow block modes)
214 *
215 * null: the initial vector is always zero. Provides compatibility with
216 * obsolete loop_fish2 devices. Do not use for new devices.
217 *
218 * lmk: Compatible implementation of the block chaining mode used
219 * by the Loop-AES block device encryption system
220 * designed by Jari Ruusu. See http://loop-aes.sourceforge.net/
221 * It operates on full 512 byte sectors and uses CBC
222 * with an IV derived from the sector number, the data and
223 * optionally extra IV seed.
224 * This means that after decryption the first block
225 * of sector must be tweaked according to decrypted data.
226 * Loop-AES can use three encryption schemes:
227 * version 1: is plain aes-cbc mode
228 * version 2: uses 64 multikey scheme with lmk IV generator
229 * version 3: the same as version 2 with additional IV seed
230 * (it uses 65 keys, last key is used as IV seed)
231 *
232 * plumb: unimplemented, see:
233 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
234 */
235
236static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv,
237 struct dm_crypt_request *dmreq)
238{
239 memset(iv, 0, cc->iv_size);
240 *(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff);
241
242 return 0;
243}
244
245static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
246 struct dm_crypt_request *dmreq)
247{
248 memset(iv, 0, cc->iv_size);
249 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
250
251 return 0;
252}
253
254/* Initialise ESSIV - compute salt but no local memory allocations */
255static int crypt_iv_essiv_init(struct crypt_config *cc)
256{
257 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
258 struct hash_desc desc;
259 struct scatterlist sg;
260 struct crypto_cipher *essiv_tfm;
261 int err, cpu;
262
263 sg_init_one(&sg, cc->key, cc->key_size);
264 desc.tfm = essiv->hash_tfm;
265 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
266
267 err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt);
268 if (err)
269 return err;
270
271 for_each_possible_cpu(cpu) {
272 essiv_tfm = per_cpu_ptr(cc->cpu, cpu)->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
280 return 0;
281}
282
283/* Wipe salt and reset key derived from volume key */
284static int crypt_iv_essiv_wipe(struct crypt_config *cc)
285{
286 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
287 unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm);
288 struct crypto_cipher *essiv_tfm;
289 int cpu, r, err = 0;
290
291 memset(essiv->salt, 0, salt_size);
292
293 for_each_possible_cpu(cpu) {
294 essiv_tfm = per_cpu_ptr(cc->cpu, cpu)->iv_private;
295 r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size);
296 if (r)
297 err = r;
298 }
299
300 return err;
301}
302
303/* Set up per cpu cipher state */
304static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc,
305 struct dm_target *ti,
306 u8 *salt, unsigned saltsize)
307{
308 struct crypto_cipher *essiv_tfm;
309 int err;
310
311 /* Setup the essiv_tfm with the given salt */
312 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
313 if (IS_ERR(essiv_tfm)) {
314 ti->error = "Error allocating crypto tfm for ESSIV";
315 return essiv_tfm;
316 }
317
318 if (crypto_cipher_blocksize(essiv_tfm) !=
319 crypto_ablkcipher_ivsize(any_tfm(cc))) {
320 ti->error = "Block size of ESSIV cipher does "
321 "not match IV size of block cipher";
322 crypto_free_cipher(essiv_tfm);
323 return ERR_PTR(-EINVAL);
324 }
325
326 err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
327 if (err) {
328 ti->error = "Failed to set key for ESSIV cipher";
329 crypto_free_cipher(essiv_tfm);
330 return ERR_PTR(err);
331 }
332
333 return essiv_tfm;
334}
335
336static void crypt_iv_essiv_dtr(struct crypt_config *cc)
337{
338 int cpu;
339 struct crypt_cpu *cpu_cc;
340 struct crypto_cipher *essiv_tfm;
341 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
342
343 crypto_free_hash(essiv->hash_tfm);
344 essiv->hash_tfm = NULL;
345
346 kzfree(essiv->salt);
347 essiv->salt = NULL;
348
349 for_each_possible_cpu(cpu) {
350 cpu_cc = per_cpu_ptr(cc->cpu, cpu);
351 essiv_tfm = cpu_cc->iv_private;
352
353 if (essiv_tfm)
354 crypto_free_cipher(essiv_tfm);
355
356 cpu_cc->iv_private = NULL;
357 }
358}
359
360static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
361 const char *opts)
362{
363 struct crypto_cipher *essiv_tfm = NULL;
364 struct crypto_hash *hash_tfm = NULL;
365 u8 *salt = NULL;
366 int err, cpu;
367
368 if (!opts) {
369 ti->error = "Digest algorithm missing for ESSIV mode";
370 return -EINVAL;
371 }
372
373 /* Allocate hash algorithm */
374 hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
375 if (IS_ERR(hash_tfm)) {
376 ti->error = "Error initializing ESSIV hash";
377 err = PTR_ERR(hash_tfm);
378 goto bad;
379 }
380
381 salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL);
382 if (!salt) {
383 ti->error = "Error kmallocing salt storage in ESSIV";
384 err = -ENOMEM;
385 goto bad;
386 }
387
388 cc->iv_gen_private.essiv.salt = salt;
389 cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
390
391 for_each_possible_cpu(cpu) {
392 essiv_tfm = setup_essiv_cpu(cc, ti, salt,
393 crypto_hash_digestsize(hash_tfm));
394 if (IS_ERR(essiv_tfm)) {
395 crypt_iv_essiv_dtr(cc);
396 return PTR_ERR(essiv_tfm);
397 }
398 per_cpu_ptr(cc->cpu, cpu)->iv_private = essiv_tfm;
399 }
400
401 return 0;
402
403bad:
404 if (hash_tfm && !IS_ERR(hash_tfm))
405 crypto_free_hash(hash_tfm);
406 kfree(salt);
407 return err;
408}
409
410static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv,
411 struct dm_crypt_request *dmreq)
412{
413 struct crypto_cipher *essiv_tfm = this_crypt_config(cc)->iv_private;
414
415 memset(iv, 0, cc->iv_size);
416 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
417 crypto_cipher_encrypt_one(essiv_tfm, iv, iv);
418
419 return 0;
420}
421
422static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
423 const char *opts)
424{
425 unsigned bs = crypto_ablkcipher_blocksize(any_tfm(cc));
426 int log = ilog2(bs);
427
428 /* we need to calculate how far we must shift the sector count
429 * to get the cipher block count, we use this shift in _gen */
430
431 if (1 << log != bs) {
432 ti->error = "cypher blocksize is not a power of 2";
433 return -EINVAL;
434 }
435
436 if (log > 9) {
437 ti->error = "cypher blocksize is > 512";
438 return -EINVAL;
439 }
440
441 cc->iv_gen_private.benbi.shift = 9 - log;
442
443 return 0;
444}
445
446static void crypt_iv_benbi_dtr(struct crypt_config *cc)
447{
448}
449
450static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv,
451 struct dm_crypt_request *dmreq)
452{
453 __be64 val;
454
455 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
456
457 val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1);
458 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
459
460 return 0;
461}
462
463static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv,
464 struct dm_crypt_request *dmreq)
465{
466 memset(iv, 0, cc->iv_size);
467
468 return 0;
469}
470
471static void crypt_iv_lmk_dtr(struct crypt_config *cc)
472{
473 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
474
475 if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm))
476 crypto_free_shash(lmk->hash_tfm);
477 lmk->hash_tfm = NULL;
478
479 kzfree(lmk->seed);
480 lmk->seed = NULL;
481}
482
483static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti,
484 const char *opts)
485{
486 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
487
488 lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0);
489 if (IS_ERR(lmk->hash_tfm)) {
490 ti->error = "Error initializing LMK hash";
491 return PTR_ERR(lmk->hash_tfm);
492 }
493
494 /* No seed in LMK version 2 */
495 if (cc->key_parts == cc->tfms_count) {
496 lmk->seed = NULL;
497 return 0;
498 }
499
500 lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL);
501 if (!lmk->seed) {
502 crypt_iv_lmk_dtr(cc);
503 ti->error = "Error kmallocing seed storage in LMK";
504 return -ENOMEM;
505 }
506
507 return 0;
508}
509
510static int crypt_iv_lmk_init(struct crypt_config *cc)
511{
512 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
513 int subkey_size = cc->key_size / cc->key_parts;
514
515 /* LMK seed is on the position of LMK_KEYS + 1 key */
516 if (lmk->seed)
517 memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size),
518 crypto_shash_digestsize(lmk->hash_tfm));
519
520 return 0;
521}
522
523static int crypt_iv_lmk_wipe(struct crypt_config *cc)
524{
525 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
526
527 if (lmk->seed)
528 memset(lmk->seed, 0, LMK_SEED_SIZE);
529
530 return 0;
531}
532
533static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv,
534 struct dm_crypt_request *dmreq,
535 u8 *data)
536{
537 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
538 struct {
539 struct shash_desc desc;
540 char ctx[crypto_shash_descsize(lmk->hash_tfm)];
541 } sdesc;
542 struct md5_state md5state;
543 u32 buf[4];
544 int i, r;
545
546 sdesc.desc.tfm = lmk->hash_tfm;
547 sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
548
549 r = crypto_shash_init(&sdesc.desc);
550 if (r)
551 return r;
552
553 if (lmk->seed) {
554 r = crypto_shash_update(&sdesc.desc, lmk->seed, LMK_SEED_SIZE);
555 if (r)
556 return r;
557 }
558
559 /* Sector is always 512B, block size 16, add data of blocks 1-31 */
560 r = crypto_shash_update(&sdesc.desc, data + 16, 16 * 31);
561 if (r)
562 return r;
563
564 /* Sector is cropped to 56 bits here */
565 buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF);
566 buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000);
567 buf[2] = cpu_to_le32(4024);
568 buf[3] = 0;
569 r = crypto_shash_update(&sdesc.desc, (u8 *)buf, sizeof(buf));
570 if (r)
571 return r;
572
573 /* No MD5 padding here */
574 r = crypto_shash_export(&sdesc.desc, &md5state);
575 if (r)
576 return r;
577
578 for (i = 0; i < MD5_HASH_WORDS; i++)
579 __cpu_to_le32s(&md5state.hash[i]);
580 memcpy(iv, &md5state.hash, cc->iv_size);
581
582 return 0;
583}
584
585static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv,
586 struct dm_crypt_request *dmreq)
587{
588 u8 *src;
589 int r = 0;
590
591 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) {
592 src = kmap_atomic(sg_page(&dmreq->sg_in));
593 r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset);
594 kunmap_atomic(src);
595 } else
596 memset(iv, 0, cc->iv_size);
597
598 return r;
599}
600
601static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv,
602 struct dm_crypt_request *dmreq)
603{
604 u8 *dst;
605 int r;
606
607 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE)
608 return 0;
609
610 dst = kmap_atomic(sg_page(&dmreq->sg_out));
611 r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset);
612
613 /* Tweak the first block of plaintext sector */
614 if (!r)
615 crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size);
616
617 kunmap_atomic(dst);
618 return r;
619}
620
621static struct crypt_iv_operations crypt_iv_plain_ops = {
622 .generator = crypt_iv_plain_gen
623};
624
625static struct crypt_iv_operations crypt_iv_plain64_ops = {
626 .generator = crypt_iv_plain64_gen
627};
628
629static struct crypt_iv_operations crypt_iv_essiv_ops = {
630 .ctr = crypt_iv_essiv_ctr,
631 .dtr = crypt_iv_essiv_dtr,
632 .init = crypt_iv_essiv_init,
633 .wipe = crypt_iv_essiv_wipe,
634 .generator = crypt_iv_essiv_gen
635};
636
637static struct crypt_iv_operations crypt_iv_benbi_ops = {
638 .ctr = crypt_iv_benbi_ctr,
639 .dtr = crypt_iv_benbi_dtr,
640 .generator = crypt_iv_benbi_gen
641};
642
643static struct crypt_iv_operations crypt_iv_null_ops = {
644 .generator = crypt_iv_null_gen
645};
646
647static struct crypt_iv_operations crypt_iv_lmk_ops = {
648 .ctr = crypt_iv_lmk_ctr,
649 .dtr = crypt_iv_lmk_dtr,
650 .init = crypt_iv_lmk_init,
651 .wipe = crypt_iv_lmk_wipe,
652 .generator = crypt_iv_lmk_gen,
653 .post = crypt_iv_lmk_post
654};
655
656static void crypt_convert_init(struct crypt_config *cc,
657 struct convert_context *ctx,
658 struct bio *bio_out, struct bio *bio_in,
659 sector_t sector)
660{
661 ctx->bio_in = bio_in;
662 ctx->bio_out = bio_out;
663 ctx->offset_in = 0;
664 ctx->offset_out = 0;
665 ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
666 ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
667 ctx->sector = sector + cc->iv_offset;
668 init_completion(&ctx->restart);
669}
670
671static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
672 struct ablkcipher_request *req)
673{
674 return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
675}
676
677static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc,
678 struct dm_crypt_request *dmreq)
679{
680 return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start);
681}
682
683static u8 *iv_of_dmreq(struct crypt_config *cc,
684 struct dm_crypt_request *dmreq)
685{
686 return (u8 *)ALIGN((unsigned long)(dmreq + 1),
687 crypto_ablkcipher_alignmask(any_tfm(cc)) + 1);
688}
689
690static int crypt_convert_block(struct crypt_config *cc,
691 struct convert_context *ctx,
692 struct ablkcipher_request *req)
693{
694 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
695 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
696 struct dm_crypt_request *dmreq;
697 u8 *iv;
698 int r = 0;
699
700 dmreq = dmreq_of_req(cc, req);
701 iv = iv_of_dmreq(cc, dmreq);
702
703 dmreq->iv_sector = ctx->sector;
704 dmreq->ctx = ctx;
705 sg_init_table(&dmreq->sg_in, 1);
706 sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
707 bv_in->bv_offset + ctx->offset_in);
708
709 sg_init_table(&dmreq->sg_out, 1);
710 sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
711 bv_out->bv_offset + ctx->offset_out);
712
713 ctx->offset_in += 1 << SECTOR_SHIFT;
714 if (ctx->offset_in >= bv_in->bv_len) {
715 ctx->offset_in = 0;
716 ctx->idx_in++;
717 }
718
719 ctx->offset_out += 1 << SECTOR_SHIFT;
720 if (ctx->offset_out >= bv_out->bv_len) {
721 ctx->offset_out = 0;
722 ctx->idx_out++;
723 }
724
725 if (cc->iv_gen_ops) {
726 r = cc->iv_gen_ops->generator(cc, iv, dmreq);
727 if (r < 0)
728 return r;
729 }
730
731 ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
732 1 << SECTOR_SHIFT, iv);
733
734 if (bio_data_dir(ctx->bio_in) == WRITE)
735 r = crypto_ablkcipher_encrypt(req);
736 else
737 r = crypto_ablkcipher_decrypt(req);
738
739 if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
740 r = cc->iv_gen_ops->post(cc, iv, dmreq);
741
742 return r;
743}
744
745static void kcryptd_async_done(struct crypto_async_request *async_req,
746 int error);
747
748static void crypt_alloc_req(struct crypt_config *cc,
749 struct convert_context *ctx)
750{
751 struct crypt_cpu *this_cc = this_crypt_config(cc);
752 unsigned key_index = ctx->sector & (cc->tfms_count - 1);
753
754 if (!this_cc->req)
755 this_cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
756
757 ablkcipher_request_set_tfm(this_cc->req, this_cc->tfms[key_index]);
758 ablkcipher_request_set_callback(this_cc->req,
759 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
760 kcryptd_async_done, dmreq_of_req(cc, this_cc->req));
761}
762
763/*
764 * Encrypt / decrypt data from one bio to another one (can be the same one)
765 */
766static int crypt_convert(struct crypt_config *cc,
767 struct convert_context *ctx)
768{
769 struct crypt_cpu *this_cc = this_crypt_config(cc);
770 int r;
771
772 atomic_set(&ctx->pending, 1);
773
774 while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
775 ctx->idx_out < ctx->bio_out->bi_vcnt) {
776
777 crypt_alloc_req(cc, ctx);
778
779 atomic_inc(&ctx->pending);
780
781 r = crypt_convert_block(cc, ctx, this_cc->req);
782
783 switch (r) {
784 /* async */
785 case -EBUSY:
786 wait_for_completion(&ctx->restart);
787 INIT_COMPLETION(ctx->restart);
788 /* fall through*/
789 case -EINPROGRESS:
790 this_cc->req = NULL;
791 ctx->sector++;
792 continue;
793
794 /* sync */
795 case 0:
796 atomic_dec(&ctx->pending);
797 ctx->sector++;
798 cond_resched();
799 continue;
800
801 /* error */
802 default:
803 atomic_dec(&ctx->pending);
804 return r;
805 }
806 }
807
808 return 0;
809}
810
811static void dm_crypt_bio_destructor(struct bio *bio)
812{
813 struct dm_crypt_io *io = bio->bi_private;
814 struct crypt_config *cc = io->target->private;
815
816 bio_free(bio, cc->bs);
817}
818
819/*
820 * Generate a new unfragmented bio with the given size
821 * This should never violate the device limitations
822 * May return a smaller bio when running out of pages, indicated by
823 * *out_of_pages set to 1.
824 */
825static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
826 unsigned *out_of_pages)
827{
828 struct crypt_config *cc = io->target->private;
829 struct bio *clone;
830 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
831 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
832 unsigned i, len;
833 struct page *page;
834
835 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
836 if (!clone)
837 return NULL;
838
839 clone_init(io, clone);
840 *out_of_pages = 0;
841
842 for (i = 0; i < nr_iovecs; i++) {
843 page = mempool_alloc(cc->page_pool, gfp_mask);
844 if (!page) {
845 *out_of_pages = 1;
846 break;
847 }
848
849 /*
850 * If additional pages cannot be allocated without waiting,
851 * return a partially-allocated bio. The caller will then try
852 * to allocate more bios while submitting this partial bio.
853 */
854 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
855
856 len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
857
858 if (!bio_add_page(clone, page, len, 0)) {
859 mempool_free(page, cc->page_pool);
860 break;
861 }
862
863 size -= len;
864 }
865
866 if (!clone->bi_size) {
867 bio_put(clone);
868 return NULL;
869 }
870
871 return clone;
872}
873
874static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
875{
876 unsigned int i;
877 struct bio_vec *bv;
878
879 for (i = 0; i < clone->bi_vcnt; i++) {
880 bv = bio_iovec_idx(clone, i);
881 BUG_ON(!bv->bv_page);
882 mempool_free(bv->bv_page, cc->page_pool);
883 bv->bv_page = NULL;
884 }
885}
886
887static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti,
888 struct bio *bio, sector_t sector)
889{
890 struct crypt_config *cc = ti->private;
891 struct dm_crypt_io *io;
892
893 io = mempool_alloc(cc->io_pool, GFP_NOIO);
894 io->target = ti;
895 io->base_bio = bio;
896 io->sector = sector;
897 io->error = 0;
898 io->base_io = NULL;
899 atomic_set(&io->pending, 0);
900
901 return io;
902}
903
904static void crypt_inc_pending(struct dm_crypt_io *io)
905{
906 atomic_inc(&io->pending);
907}
908
909/*
910 * One of the bios was finished. Check for completion of
911 * the whole request and correctly clean up the buffer.
912 * If base_io is set, wait for the last fragment to complete.
913 */
914static void crypt_dec_pending(struct dm_crypt_io *io)
915{
916 struct crypt_config *cc = io->target->private;
917 struct bio *base_bio = io->base_bio;
918 struct dm_crypt_io *base_io = io->base_io;
919 int error = io->error;
920
921 if (!atomic_dec_and_test(&io->pending))
922 return;
923
924 mempool_free(io, cc->io_pool);
925
926 if (likely(!base_io))
927 bio_endio(base_bio, error);
928 else {
929 if (error && !base_io->error)
930 base_io->error = error;
931 crypt_dec_pending(base_io);
932 }
933}
934
935/*
936 * kcryptd/kcryptd_io:
937 *
938 * Needed because it would be very unwise to do decryption in an
939 * interrupt context.
940 *
941 * kcryptd performs the actual encryption or decryption.
942 *
943 * kcryptd_io performs the IO submission.
944 *
945 * They must be separated as otherwise the final stages could be
946 * starved by new requests which can block in the first stages due
947 * to memory allocation.
948 *
949 * The work is done per CPU global for all dm-crypt instances.
950 * They should not depend on each other and do not block.
951 */
952static void crypt_endio(struct bio *clone, int error)
953{
954 struct dm_crypt_io *io = clone->bi_private;
955 struct crypt_config *cc = io->target->private;
956 unsigned rw = bio_data_dir(clone);
957
958 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
959 error = -EIO;
960
961 /*
962 * free the processed pages
963 */
964 if (rw == WRITE)
965 crypt_free_buffer_pages(cc, clone);
966
967 bio_put(clone);
968
969 if (rw == READ && !error) {
970 kcryptd_queue_crypt(io);
971 return;
972 }
973
974 if (unlikely(error))
975 io->error = error;
976
977 crypt_dec_pending(io);
978}
979
980static void clone_init(struct dm_crypt_io *io, struct bio *clone)
981{
982 struct crypt_config *cc = io->target->private;
983
984 clone->bi_private = io;
985 clone->bi_end_io = crypt_endio;
986 clone->bi_bdev = cc->dev->bdev;
987 clone->bi_rw = io->base_bio->bi_rw;
988 clone->bi_destructor = dm_crypt_bio_destructor;
989}
990
991static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
992{
993 struct crypt_config *cc = io->target->private;
994 struct bio *base_bio = io->base_bio;
995 struct bio *clone;
996
997 /*
998 * The block layer might modify the bvec array, so always
999 * copy the required bvecs because we need the original
1000 * one in order to decrypt the whole bio data *afterwards*.
1001 */
1002 clone = bio_alloc_bioset(gfp, bio_segments(base_bio), cc->bs);
1003 if (!clone)
1004 return 1;
1005
1006 crypt_inc_pending(io);
1007
1008 clone_init(io, clone);
1009 clone->bi_idx = 0;
1010 clone->bi_vcnt = bio_segments(base_bio);
1011 clone->bi_size = base_bio->bi_size;
1012 clone->bi_sector = cc->start + io->sector;
1013 memcpy(clone->bi_io_vec, bio_iovec(base_bio),
1014 sizeof(struct bio_vec) * clone->bi_vcnt);
1015
1016 generic_make_request(clone);
1017 return 0;
1018}
1019
1020static void kcryptd_io_write(struct dm_crypt_io *io)
1021{
1022 struct bio *clone = io->ctx.bio_out;
1023 generic_make_request(clone);
1024}
1025
1026static void kcryptd_io(struct work_struct *work)
1027{
1028 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1029
1030 if (bio_data_dir(io->base_bio) == READ) {
1031 crypt_inc_pending(io);
1032 if (kcryptd_io_read(io, GFP_NOIO))
1033 io->error = -ENOMEM;
1034 crypt_dec_pending(io);
1035 } else
1036 kcryptd_io_write(io);
1037}
1038
1039static void kcryptd_queue_io(struct dm_crypt_io *io)
1040{
1041 struct crypt_config *cc = io->target->private;
1042
1043 INIT_WORK(&io->work, kcryptd_io);
1044 queue_work(cc->io_queue, &io->work);
1045}
1046
1047static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
1048{
1049 struct bio *clone = io->ctx.bio_out;
1050 struct crypt_config *cc = io->target->private;
1051
1052 if (unlikely(io->error < 0)) {
1053 crypt_free_buffer_pages(cc, clone);
1054 bio_put(clone);
1055 crypt_dec_pending(io);
1056 return;
1057 }
1058
1059 /* crypt_convert should have filled the clone bio */
1060 BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
1061
1062 clone->bi_sector = cc->start + io->sector;
1063
1064 if (async)
1065 kcryptd_queue_io(io);
1066 else
1067 generic_make_request(clone);
1068}
1069
1070static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
1071{
1072 struct crypt_config *cc = io->target->private;
1073 struct bio *clone;
1074 struct dm_crypt_io *new_io;
1075 int crypt_finished;
1076 unsigned out_of_pages = 0;
1077 unsigned remaining = io->base_bio->bi_size;
1078 sector_t sector = io->sector;
1079 int r;
1080
1081 /*
1082 * Prevent io from disappearing until this function completes.
1083 */
1084 crypt_inc_pending(io);
1085 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
1086
1087 /*
1088 * The allocated buffers can be smaller than the whole bio,
1089 * so repeat the whole process until all the data can be handled.
1090 */
1091 while (remaining) {
1092 clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
1093 if (unlikely(!clone)) {
1094 io->error = -ENOMEM;
1095 break;
1096 }
1097
1098 io->ctx.bio_out = clone;
1099 io->ctx.idx_out = 0;
1100
1101 remaining -= clone->bi_size;
1102 sector += bio_sectors(clone);
1103
1104 crypt_inc_pending(io);
1105
1106 r = crypt_convert(cc, &io->ctx);
1107 if (r < 0)
1108 io->error = -EIO;
1109
1110 crypt_finished = atomic_dec_and_test(&io->ctx.pending);
1111
1112 /* Encryption was already finished, submit io now */
1113 if (crypt_finished) {
1114 kcryptd_crypt_write_io_submit(io, 0);
1115
1116 /*
1117 * If there was an error, do not try next fragments.
1118 * For async, error is processed in async handler.
1119 */
1120 if (unlikely(r < 0))
1121 break;
1122
1123 io->sector = sector;
1124 }
1125
1126 /*
1127 * Out of memory -> run queues
1128 * But don't wait if split was due to the io size restriction
1129 */
1130 if (unlikely(out_of_pages))
1131 congestion_wait(BLK_RW_ASYNC, HZ/100);
1132
1133 /*
1134 * With async crypto it is unsafe to share the crypto context
1135 * between fragments, so switch to a new dm_crypt_io structure.
1136 */
1137 if (unlikely(!crypt_finished && remaining)) {
1138 new_io = crypt_io_alloc(io->target, io->base_bio,
1139 sector);
1140 crypt_inc_pending(new_io);
1141 crypt_convert_init(cc, &new_io->ctx, NULL,
1142 io->base_bio, sector);
1143 new_io->ctx.idx_in = io->ctx.idx_in;
1144 new_io->ctx.offset_in = io->ctx.offset_in;
1145
1146 /*
1147 * Fragments after the first use the base_io
1148 * pending count.
1149 */
1150 if (!io->base_io)
1151 new_io->base_io = io;
1152 else {
1153 new_io->base_io = io->base_io;
1154 crypt_inc_pending(io->base_io);
1155 crypt_dec_pending(io);
1156 }
1157
1158 io = new_io;
1159 }
1160 }
1161
1162 crypt_dec_pending(io);
1163}
1164
1165static void kcryptd_crypt_read_done(struct dm_crypt_io *io)
1166{
1167 crypt_dec_pending(io);
1168}
1169
1170static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
1171{
1172 struct crypt_config *cc = io->target->private;
1173 int r = 0;
1174
1175 crypt_inc_pending(io);
1176
1177 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
1178 io->sector);
1179
1180 r = crypt_convert(cc, &io->ctx);
1181 if (r < 0)
1182 io->error = -EIO;
1183
1184 if (atomic_dec_and_test(&io->ctx.pending))
1185 kcryptd_crypt_read_done(io);
1186
1187 crypt_dec_pending(io);
1188}
1189
1190static void kcryptd_async_done(struct crypto_async_request *async_req,
1191 int error)
1192{
1193 struct dm_crypt_request *dmreq = async_req->data;
1194 struct convert_context *ctx = dmreq->ctx;
1195 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
1196 struct crypt_config *cc = io->target->private;
1197
1198 if (error == -EINPROGRESS) {
1199 complete(&ctx->restart);
1200 return;
1201 }
1202
1203 if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
1204 error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
1205
1206 if (error < 0)
1207 io->error = -EIO;
1208
1209 mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool);
1210
1211 if (!atomic_dec_and_test(&ctx->pending))
1212 return;
1213
1214 if (bio_data_dir(io->base_bio) == READ)
1215 kcryptd_crypt_read_done(io);
1216 else
1217 kcryptd_crypt_write_io_submit(io, 1);
1218}
1219
1220static void kcryptd_crypt(struct work_struct *work)
1221{
1222 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1223
1224 if (bio_data_dir(io->base_bio) == READ)
1225 kcryptd_crypt_read_convert(io);
1226 else
1227 kcryptd_crypt_write_convert(io);
1228}
1229
1230static void kcryptd_queue_crypt(struct dm_crypt_io *io)
1231{
1232 struct crypt_config *cc = io->target->private;
1233
1234 INIT_WORK(&io->work, kcryptd_crypt);
1235 queue_work(cc->crypt_queue, &io->work);
1236}
1237
1238/*
1239 * Decode key from its hex representation
1240 */
1241static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
1242{
1243 char buffer[3];
1244 char *endp;
1245 unsigned int i;
1246
1247 buffer[2] = '\0';
1248
1249 for (i = 0; i < size; i++) {
1250 buffer[0] = *hex++;
1251 buffer[1] = *hex++;
1252
1253 key[i] = (u8)simple_strtoul(buffer, &endp, 16);
1254
1255 if (endp != &buffer[2])
1256 return -EINVAL;
1257 }
1258
1259 if (*hex != '\0')
1260 return -EINVAL;
1261
1262 return 0;
1263}
1264
1265/*
1266 * Encode key into its hex representation
1267 */
1268static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
1269{
1270 unsigned int i;
1271
1272 for (i = 0; i < size; i++) {
1273 sprintf(hex, "%02x", *key);
1274 hex += 2;
1275 key++;
1276 }
1277}
1278
1279static void crypt_free_tfms(struct crypt_config *cc, int cpu)
1280{
1281 struct crypt_cpu *cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1282 unsigned i;
1283
1284 for (i = 0; i < cc->tfms_count; i++)
1285 if (cpu_cc->tfms[i] && !IS_ERR(cpu_cc->tfms[i])) {
1286 crypto_free_ablkcipher(cpu_cc->tfms[i]);
1287 cpu_cc->tfms[i] = NULL;
1288 }
1289}
1290
1291static int crypt_alloc_tfms(struct crypt_config *cc, int cpu, char *ciphermode)
1292{
1293 struct crypt_cpu *cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1294 unsigned i;
1295 int err;
1296
1297 for (i = 0; i < cc->tfms_count; i++) {
1298 cpu_cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0);
1299 if (IS_ERR(cpu_cc->tfms[i])) {
1300 err = PTR_ERR(cpu_cc->tfms[i]);
1301 crypt_free_tfms(cc, cpu);
1302 return err;
1303 }
1304 }
1305
1306 return 0;
1307}
1308
1309static int crypt_setkey_allcpus(struct crypt_config *cc)
1310{
1311 unsigned subkey_size = cc->key_size >> ilog2(cc->tfms_count);
1312 int cpu, err = 0, i, r;
1313
1314 for_each_possible_cpu(cpu) {
1315 for (i = 0; i < cc->tfms_count; i++) {
1316 r = crypto_ablkcipher_setkey(per_cpu_ptr(cc->cpu, cpu)->tfms[i],
1317 cc->key + (i * subkey_size), subkey_size);
1318 if (r)
1319 err = r;
1320 }
1321 }
1322
1323 return err;
1324}
1325
1326static int crypt_set_key(struct crypt_config *cc, char *key)
1327{
1328 int r = -EINVAL;
1329 int key_string_len = strlen(key);
1330
1331 /* The key size may not be changed. */
1332 if (cc->key_size != (key_string_len >> 1))
1333 goto out;
1334
1335 /* Hyphen (which gives a key_size of zero) means there is no key. */
1336 if (!cc->key_size && strcmp(key, "-"))
1337 goto out;
1338
1339 if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
1340 goto out;
1341
1342 set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1343
1344 r = crypt_setkey_allcpus(cc);
1345
1346out:
1347 /* Hex key string not needed after here, so wipe it. */
1348 memset(key, '0', key_string_len);
1349
1350 return r;
1351}
1352
1353static int crypt_wipe_key(struct crypt_config *cc)
1354{
1355 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1356 memset(&cc->key, 0, cc->key_size * sizeof(u8));
1357
1358 return crypt_setkey_allcpus(cc);
1359}
1360
1361static void crypt_dtr(struct dm_target *ti)
1362{
1363 struct crypt_config *cc = ti->private;
1364 struct crypt_cpu *cpu_cc;
1365 int cpu;
1366
1367 ti->private = NULL;
1368
1369 if (!cc)
1370 return;
1371
1372 if (cc->io_queue)
1373 destroy_workqueue(cc->io_queue);
1374 if (cc->crypt_queue)
1375 destroy_workqueue(cc->crypt_queue);
1376
1377 if (cc->cpu)
1378 for_each_possible_cpu(cpu) {
1379 cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1380 if (cpu_cc->req)
1381 mempool_free(cpu_cc->req, cc->req_pool);
1382 crypt_free_tfms(cc, cpu);
1383 }
1384
1385 if (cc->bs)
1386 bioset_free(cc->bs);
1387
1388 if (cc->page_pool)
1389 mempool_destroy(cc->page_pool);
1390 if (cc->req_pool)
1391 mempool_destroy(cc->req_pool);
1392 if (cc->io_pool)
1393 mempool_destroy(cc->io_pool);
1394
1395 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1396 cc->iv_gen_ops->dtr(cc);
1397
1398 if (cc->dev)
1399 dm_put_device(ti, cc->dev);
1400
1401 if (cc->cpu)
1402 free_percpu(cc->cpu);
1403
1404 kzfree(cc->cipher);
1405 kzfree(cc->cipher_string);
1406
1407 /* Must zero key material before freeing */
1408 kzfree(cc);
1409}
1410
1411static int crypt_ctr_cipher(struct dm_target *ti,
1412 char *cipher_in, char *key)
1413{
1414 struct crypt_config *cc = ti->private;
1415 char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount;
1416 char *cipher_api = NULL;
1417 int cpu, ret = -EINVAL;
1418 char dummy;
1419
1420 /* Convert to crypto api definition? */
1421 if (strchr(cipher_in, '(')) {
1422 ti->error = "Bad cipher specification";
1423 return -EINVAL;
1424 }
1425
1426 cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
1427 if (!cc->cipher_string)
1428 goto bad_mem;
1429
1430 /*
1431 * Legacy dm-crypt cipher specification
1432 * cipher[:keycount]-mode-iv:ivopts
1433 */
1434 tmp = cipher_in;
1435 keycount = strsep(&tmp, "-");
1436 cipher = strsep(&keycount, ":");
1437
1438 if (!keycount)
1439 cc->tfms_count = 1;
1440 else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 ||
1441 !is_power_of_2(cc->tfms_count)) {
1442 ti->error = "Bad cipher key count specification";
1443 return -EINVAL;
1444 }
1445 cc->key_parts = cc->tfms_count;
1446
1447 cc->cipher = kstrdup(cipher, GFP_KERNEL);
1448 if (!cc->cipher)
1449 goto bad_mem;
1450
1451 chainmode = strsep(&tmp, "-");
1452 ivopts = strsep(&tmp, "-");
1453 ivmode = strsep(&ivopts, ":");
1454
1455 if (tmp)
1456 DMWARN("Ignoring unexpected additional cipher options");
1457
1458 cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)) +
1459 cc->tfms_count * sizeof(*(cc->cpu->tfms)),
1460 __alignof__(struct crypt_cpu));
1461 if (!cc->cpu) {
1462 ti->error = "Cannot allocate per cpu state";
1463 goto bad_mem;
1464 }
1465
1466 /*
1467 * For compatibility with the original dm-crypt mapping format, if
1468 * only the cipher name is supplied, use cbc-plain.
1469 */
1470 if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
1471 chainmode = "cbc";
1472 ivmode = "plain";
1473 }
1474
1475 if (strcmp(chainmode, "ecb") && !ivmode) {
1476 ti->error = "IV mechanism required";
1477 return -EINVAL;
1478 }
1479
1480 cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
1481 if (!cipher_api)
1482 goto bad_mem;
1483
1484 ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
1485 "%s(%s)", chainmode, cipher);
1486 if (ret < 0) {
1487 kfree(cipher_api);
1488 goto bad_mem;
1489 }
1490
1491 /* Allocate cipher */
1492 for_each_possible_cpu(cpu) {
1493 ret = crypt_alloc_tfms(cc, cpu, cipher_api);
1494 if (ret < 0) {
1495 ti->error = "Error allocating crypto tfm";
1496 goto bad;
1497 }
1498 }
1499
1500 /* Initialize and set key */
1501 ret = crypt_set_key(cc, key);
1502 if (ret < 0) {
1503 ti->error = "Error decoding and setting key";
1504 goto bad;
1505 }
1506
1507 /* Initialize IV */
1508 cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc));
1509 if (cc->iv_size)
1510 /* at least a 64 bit sector number should fit in our buffer */
1511 cc->iv_size = max(cc->iv_size,
1512 (unsigned int)(sizeof(u64) / sizeof(u8)));
1513 else if (ivmode) {
1514 DMWARN("Selected cipher does not support IVs");
1515 ivmode = NULL;
1516 }
1517
1518 /* Choose ivmode, see comments at iv code. */
1519 if (ivmode == NULL)
1520 cc->iv_gen_ops = NULL;
1521 else if (strcmp(ivmode, "plain") == 0)
1522 cc->iv_gen_ops = &crypt_iv_plain_ops;
1523 else if (strcmp(ivmode, "plain64") == 0)
1524 cc->iv_gen_ops = &crypt_iv_plain64_ops;
1525 else if (strcmp(ivmode, "essiv") == 0)
1526 cc->iv_gen_ops = &crypt_iv_essiv_ops;
1527 else if (strcmp(ivmode, "benbi") == 0)
1528 cc->iv_gen_ops = &crypt_iv_benbi_ops;
1529 else if (strcmp(ivmode, "null") == 0)
1530 cc->iv_gen_ops = &crypt_iv_null_ops;
1531 else if (strcmp(ivmode, "lmk") == 0) {
1532 cc->iv_gen_ops = &crypt_iv_lmk_ops;
1533 /* Version 2 and 3 is recognised according
1534 * to length of provided multi-key string.
1535 * If present (version 3), last key is used as IV seed.
1536 */
1537 if (cc->key_size % cc->key_parts)
1538 cc->key_parts++;
1539 } else {
1540 ret = -EINVAL;
1541 ti->error = "Invalid IV mode";
1542 goto bad;
1543 }
1544
1545 /* Allocate IV */
1546 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
1547 ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
1548 if (ret < 0) {
1549 ti->error = "Error creating IV";
1550 goto bad;
1551 }
1552 }
1553
1554 /* Initialize IV (set keys for ESSIV etc) */
1555 if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
1556 ret = cc->iv_gen_ops->init(cc);
1557 if (ret < 0) {
1558 ti->error = "Error initialising IV";
1559 goto bad;
1560 }
1561 }
1562
1563 ret = 0;
1564bad:
1565 kfree(cipher_api);
1566 return ret;
1567
1568bad_mem:
1569 ti->error = "Cannot allocate cipher strings";
1570 return -ENOMEM;
1571}
1572
1573/*
1574 * Construct an encryption mapping:
1575 * <cipher> <key> <iv_offset> <dev_path> <start>
1576 */
1577static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1578{
1579 struct crypt_config *cc;
1580 unsigned int key_size, opt_params;
1581 unsigned long long tmpll;
1582 int ret;
1583 struct dm_arg_set as;
1584 const char *opt_string;
1585 char dummy;
1586
1587 static struct dm_arg _args[] = {
1588 {0, 1, "Invalid number of feature args"},
1589 };
1590
1591 if (argc < 5) {
1592 ti->error = "Not enough arguments";
1593 return -EINVAL;
1594 }
1595
1596 key_size = strlen(argv[1]) >> 1;
1597
1598 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
1599 if (!cc) {
1600 ti->error = "Cannot allocate encryption context";
1601 return -ENOMEM;
1602 }
1603 cc->key_size = key_size;
1604
1605 ti->private = cc;
1606 ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
1607 if (ret < 0)
1608 goto bad;
1609
1610 ret = -ENOMEM;
1611 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1612 if (!cc->io_pool) {
1613 ti->error = "Cannot allocate crypt io mempool";
1614 goto bad;
1615 }
1616
1617 cc->dmreq_start = sizeof(struct ablkcipher_request);
1618 cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc));
1619 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
1620 cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) &
1621 ~(crypto_tfm_ctx_alignment() - 1);
1622
1623 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1624 sizeof(struct dm_crypt_request) + cc->iv_size);
1625 if (!cc->req_pool) {
1626 ti->error = "Cannot allocate crypt request mempool";
1627 goto bad;
1628 }
1629
1630 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1631 if (!cc->page_pool) {
1632 ti->error = "Cannot allocate page mempool";
1633 goto bad;
1634 }
1635
1636 cc->bs = bioset_create(MIN_IOS, 0);
1637 if (!cc->bs) {
1638 ti->error = "Cannot allocate crypt bioset";
1639 goto bad;
1640 }
1641
1642 ret = -EINVAL;
1643 if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) {
1644 ti->error = "Invalid iv_offset sector";
1645 goto bad;
1646 }
1647 cc->iv_offset = tmpll;
1648
1649 if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
1650 ti->error = "Device lookup failed";
1651 goto bad;
1652 }
1653
1654 if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
1655 ti->error = "Invalid device sector";
1656 goto bad;
1657 }
1658 cc->start = tmpll;
1659
1660 argv += 5;
1661 argc -= 5;
1662
1663 /* Optional parameters */
1664 if (argc) {
1665 as.argc = argc;
1666 as.argv = argv;
1667
1668 ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1669 if (ret)
1670 goto bad;
1671
1672 opt_string = dm_shift_arg(&as);
1673
1674 if (opt_params == 1 && opt_string &&
1675 !strcasecmp(opt_string, "allow_discards"))
1676 ti->num_discard_requests = 1;
1677 else if (opt_params) {
1678 ret = -EINVAL;
1679 ti->error = "Invalid feature arguments";
1680 goto bad;
1681 }
1682 }
1683
1684 ret = -ENOMEM;
1685 cc->io_queue = alloc_workqueue("kcryptd_io",
1686 WQ_NON_REENTRANT|
1687 WQ_MEM_RECLAIM,
1688 1);
1689 if (!cc->io_queue) {
1690 ti->error = "Couldn't create kcryptd io queue";
1691 goto bad;
1692 }
1693
1694 cc->crypt_queue = alloc_workqueue("kcryptd",
1695 WQ_NON_REENTRANT|
1696 WQ_CPU_INTENSIVE|
1697 WQ_MEM_RECLAIM,
1698 1);
1699 if (!cc->crypt_queue) {
1700 ti->error = "Couldn't create kcryptd queue";
1701 goto bad;
1702 }
1703
1704 ti->num_flush_requests = 1;
1705 ti->discard_zeroes_data_unsupported = 1;
1706
1707 return 0;
1708
1709bad:
1710 crypt_dtr(ti);
1711 return ret;
1712}
1713
1714static int crypt_map(struct dm_target *ti, struct bio *bio,
1715 union map_info *map_context)
1716{
1717 struct dm_crypt_io *io;
1718 struct crypt_config *cc;
1719
1720 /*
1721 * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues.
1722 * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight
1723 * - for REQ_DISCARD caller must use flush if IO ordering matters
1724 */
1725 if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) {
1726 cc = ti->private;
1727 bio->bi_bdev = cc->dev->bdev;
1728 if (bio_sectors(bio))
1729 bio->bi_sector = cc->start + dm_target_offset(ti, bio->bi_sector);
1730 return DM_MAPIO_REMAPPED;
1731 }
1732
1733 io = crypt_io_alloc(ti, bio, dm_target_offset(ti, bio->bi_sector));
1734
1735 if (bio_data_dir(io->base_bio) == READ) {
1736 if (kcryptd_io_read(io, GFP_NOWAIT))
1737 kcryptd_queue_io(io);
1738 } else
1739 kcryptd_queue_crypt(io);
1740
1741 return DM_MAPIO_SUBMITTED;
1742}
1743
1744static int crypt_status(struct dm_target *ti, status_type_t type,
1745 char *result, unsigned int maxlen)
1746{
1747 struct crypt_config *cc = ti->private;
1748 unsigned int sz = 0;
1749
1750 switch (type) {
1751 case STATUSTYPE_INFO:
1752 result[0] = '\0';
1753 break;
1754
1755 case STATUSTYPE_TABLE:
1756 DMEMIT("%s ", cc->cipher_string);
1757
1758 if (cc->key_size > 0) {
1759 if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1760 return -ENOMEM;
1761
1762 crypt_encode_key(result + sz, cc->key, cc->key_size);
1763 sz += cc->key_size << 1;
1764 } else {
1765 if (sz >= maxlen)
1766 return -ENOMEM;
1767 result[sz++] = '-';
1768 }
1769
1770 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1771 cc->dev->name, (unsigned long long)cc->start);
1772
1773 if (ti->num_discard_requests)
1774 DMEMIT(" 1 allow_discards");
1775
1776 break;
1777 }
1778 return 0;
1779}
1780
1781static void crypt_postsuspend(struct dm_target *ti)
1782{
1783 struct crypt_config *cc = ti->private;
1784
1785 set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1786}
1787
1788static int crypt_preresume(struct dm_target *ti)
1789{
1790 struct crypt_config *cc = ti->private;
1791
1792 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1793 DMERR("aborting resume - crypt key is not set.");
1794 return -EAGAIN;
1795 }
1796
1797 return 0;
1798}
1799
1800static void crypt_resume(struct dm_target *ti)
1801{
1802 struct crypt_config *cc = ti->private;
1803
1804 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1805}
1806
1807/* Message interface
1808 * key set <key>
1809 * key wipe
1810 */
1811static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1812{
1813 struct crypt_config *cc = ti->private;
1814 int ret = -EINVAL;
1815
1816 if (argc < 2)
1817 goto error;
1818
1819 if (!strcasecmp(argv[0], "key")) {
1820 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1821 DMWARN("not suspended during key manipulation.");
1822 return -EINVAL;
1823 }
1824 if (argc == 3 && !strcasecmp(argv[1], "set")) {
1825 ret = crypt_set_key(cc, argv[2]);
1826 if (ret)
1827 return ret;
1828 if (cc->iv_gen_ops && cc->iv_gen_ops->init)
1829 ret = cc->iv_gen_ops->init(cc);
1830 return ret;
1831 }
1832 if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
1833 if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
1834 ret = cc->iv_gen_ops->wipe(cc);
1835 if (ret)
1836 return ret;
1837 }
1838 return crypt_wipe_key(cc);
1839 }
1840 }
1841
1842error:
1843 DMWARN("unrecognised message received.");
1844 return -EINVAL;
1845}
1846
1847static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1848 struct bio_vec *biovec, int max_size)
1849{
1850 struct crypt_config *cc = ti->private;
1851 struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1852
1853 if (!q->merge_bvec_fn)
1854 return max_size;
1855
1856 bvm->bi_bdev = cc->dev->bdev;
1857 bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
1858
1859 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1860}
1861
1862static int crypt_iterate_devices(struct dm_target *ti,
1863 iterate_devices_callout_fn fn, void *data)
1864{
1865 struct crypt_config *cc = ti->private;
1866
1867 return fn(ti, cc->dev, cc->start, ti->len, data);
1868}
1869
1870static struct target_type crypt_target = {
1871 .name = "crypt",
1872 .version = {1, 11, 0},
1873 .module = THIS_MODULE,
1874 .ctr = crypt_ctr,
1875 .dtr = crypt_dtr,
1876 .map = crypt_map,
1877 .status = crypt_status,
1878 .postsuspend = crypt_postsuspend,
1879 .preresume = crypt_preresume,
1880 .resume = crypt_resume,
1881 .message = crypt_message,
1882 .merge = crypt_merge,
1883 .iterate_devices = crypt_iterate_devices,
1884};
1885
1886static int __init dm_crypt_init(void)
1887{
1888 int r;
1889
1890 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1891 if (!_crypt_io_pool)
1892 return -ENOMEM;
1893
1894 r = dm_register_target(&crypt_target);
1895 if (r < 0) {
1896 DMERR("register failed %d", r);
1897 kmem_cache_destroy(_crypt_io_pool);
1898 }
1899
1900 return r;
1901}
1902
1903static void __exit dm_crypt_exit(void)
1904{
1905 dm_unregister_target(&crypt_target);
1906 kmem_cache_destroy(_crypt_io_pool);
1907}
1908
1909module_init(dm_crypt_init);
1910module_exit(dm_crypt_exit);
1911
1912MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1913MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1914MODULE_LICENSE("GPL");