Loading...
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");
1/*
2 * Copyright (C) 2003 Jana Saout <jana@saout.de>
3 * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
4 * Copyright (C) 2006-2015 Red Hat, Inc. All rights reserved.
5 * Copyright (C) 2013 Milan Broz <gmazyland@gmail.com>
6 *
7 * This file is released under the GPL.
8 */
9
10#include <linux/completion.h>
11#include <linux/err.h>
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/kernel.h>
15#include <linux/key.h>
16#include <linux/bio.h>
17#include <linux/blkdev.h>
18#include <linux/mempool.h>
19#include <linux/slab.h>
20#include <linux/crypto.h>
21#include <linux/workqueue.h>
22#include <linux/kthread.h>
23#include <linux/backing-dev.h>
24#include <linux/atomic.h>
25#include <linux/scatterlist.h>
26#include <linux/rbtree.h>
27#include <linux/ctype.h>
28#include <asm/page.h>
29#include <asm/unaligned.h>
30#include <crypto/hash.h>
31#include <crypto/md5.h>
32#include <crypto/algapi.h>
33#include <crypto/skcipher.h>
34#include <keys/user-type.h>
35
36#include <linux/device-mapper.h>
37
38#define DM_MSG_PREFIX "crypt"
39
40/*
41 * context holding the current state of a multi-part conversion
42 */
43struct convert_context {
44 struct completion restart;
45 struct bio *bio_in;
46 struct bio *bio_out;
47 struct bvec_iter iter_in;
48 struct bvec_iter iter_out;
49 sector_t cc_sector;
50 atomic_t cc_pending;
51 struct skcipher_request *req;
52};
53
54/*
55 * per bio private data
56 */
57struct dm_crypt_io {
58 struct crypt_config *cc;
59 struct bio *base_bio;
60 struct work_struct work;
61
62 struct convert_context ctx;
63
64 atomic_t io_pending;
65 int error;
66 sector_t sector;
67
68 struct rb_node rb_node;
69} CRYPTO_MINALIGN_ATTR;
70
71struct dm_crypt_request {
72 struct convert_context *ctx;
73 struct scatterlist sg_in;
74 struct scatterlist sg_out;
75 sector_t iv_sector;
76};
77
78struct crypt_config;
79
80struct crypt_iv_operations {
81 int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
82 const char *opts);
83 void (*dtr)(struct crypt_config *cc);
84 int (*init)(struct crypt_config *cc);
85 int (*wipe)(struct crypt_config *cc);
86 int (*generator)(struct crypt_config *cc, u8 *iv,
87 struct dm_crypt_request *dmreq);
88 int (*post)(struct crypt_config *cc, u8 *iv,
89 struct dm_crypt_request *dmreq);
90};
91
92struct iv_essiv_private {
93 struct crypto_ahash *hash_tfm;
94 u8 *salt;
95};
96
97struct iv_benbi_private {
98 int shift;
99};
100
101#define LMK_SEED_SIZE 64 /* hash + 0 */
102struct iv_lmk_private {
103 struct crypto_shash *hash_tfm;
104 u8 *seed;
105};
106
107#define TCW_WHITENING_SIZE 16
108struct iv_tcw_private {
109 struct crypto_shash *crc32_tfm;
110 u8 *iv_seed;
111 u8 *whitening;
112};
113
114/*
115 * Crypt: maps a linear range of a block device
116 * and encrypts / decrypts at the same time.
117 */
118enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID,
119 DM_CRYPT_SAME_CPU, DM_CRYPT_NO_OFFLOAD };
120
121/*
122 * The fields in here must be read only after initialization.
123 */
124struct crypt_config {
125 struct dm_dev *dev;
126 sector_t start;
127
128 /*
129 * pool for per bio private data, crypto requests and
130 * encryption requeusts/buffer pages
131 */
132 mempool_t *req_pool;
133 mempool_t *page_pool;
134 struct bio_set *bs;
135 struct mutex bio_alloc_lock;
136
137 struct workqueue_struct *io_queue;
138 struct workqueue_struct *crypt_queue;
139
140 struct task_struct *write_thread;
141 wait_queue_head_t write_thread_wait;
142 struct rb_root write_tree;
143
144 char *cipher;
145 char *cipher_string;
146 char *key_string;
147
148 const struct crypt_iv_operations *iv_gen_ops;
149 union {
150 struct iv_essiv_private essiv;
151 struct iv_benbi_private benbi;
152 struct iv_lmk_private lmk;
153 struct iv_tcw_private tcw;
154 } iv_gen_private;
155 sector_t iv_offset;
156 unsigned int iv_size;
157
158 /* ESSIV: struct crypto_cipher *essiv_tfm */
159 void *iv_private;
160 struct crypto_skcipher **tfms;
161 unsigned tfms_count;
162
163 /*
164 * Layout of each crypto request:
165 *
166 * struct skcipher_request
167 * context
168 * padding
169 * struct dm_crypt_request
170 * padding
171 * IV
172 *
173 * The padding is added so that dm_crypt_request and the IV are
174 * correctly aligned.
175 */
176 unsigned int dmreq_start;
177
178 unsigned int per_bio_data_size;
179
180 unsigned long flags;
181 unsigned int key_size;
182 unsigned int key_parts; /* independent parts in key buffer */
183 unsigned int key_extra_size; /* additional keys length */
184 u8 key[0];
185};
186
187#define MIN_IOS 64
188
189static void clone_init(struct dm_crypt_io *, struct bio *);
190static void kcryptd_queue_crypt(struct dm_crypt_io *io);
191static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq);
192
193/*
194 * Use this to access cipher attributes that are the same for each CPU.
195 */
196static struct crypto_skcipher *any_tfm(struct crypt_config *cc)
197{
198 return cc->tfms[0];
199}
200
201/*
202 * Different IV generation algorithms:
203 *
204 * plain: the initial vector is the 32-bit little-endian version of the sector
205 * number, padded with zeros if necessary.
206 *
207 * plain64: the initial vector is the 64-bit little-endian version of the sector
208 * number, padded with zeros if necessary.
209 *
210 * essiv: "encrypted sector|salt initial vector", the sector number is
211 * encrypted with the bulk cipher using a salt as key. The salt
212 * should be derived from the bulk cipher's key via hashing.
213 *
214 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
215 * (needed for LRW-32-AES and possible other narrow block modes)
216 *
217 * null: the initial vector is always zero. Provides compatibility with
218 * obsolete loop_fish2 devices. Do not use for new devices.
219 *
220 * lmk: Compatible implementation of the block chaining mode used
221 * by the Loop-AES block device encryption system
222 * designed by Jari Ruusu. See http://loop-aes.sourceforge.net/
223 * It operates on full 512 byte sectors and uses CBC
224 * with an IV derived from the sector number, the data and
225 * optionally extra IV seed.
226 * This means that after decryption the first block
227 * of sector must be tweaked according to decrypted data.
228 * Loop-AES can use three encryption schemes:
229 * version 1: is plain aes-cbc mode
230 * version 2: uses 64 multikey scheme with lmk IV generator
231 * version 3: the same as version 2 with additional IV seed
232 * (it uses 65 keys, last key is used as IV seed)
233 *
234 * tcw: Compatible implementation of the block chaining mode used
235 * by the TrueCrypt device encryption system (prior to version 4.1).
236 * For more info see: https://gitlab.com/cryptsetup/cryptsetup/wikis/TrueCryptOnDiskFormat
237 * It operates on full 512 byte sectors and uses CBC
238 * with an IV derived from initial key and the sector number.
239 * In addition, whitening value is applied on every sector, whitening
240 * is calculated from initial key, sector number and mixed using CRC32.
241 * Note that this encryption scheme is vulnerable to watermarking attacks
242 * and should be used for old compatible containers access only.
243 *
244 * plumb: unimplemented, see:
245 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
246 */
247
248static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv,
249 struct dm_crypt_request *dmreq)
250{
251 memset(iv, 0, cc->iv_size);
252 *(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff);
253
254 return 0;
255}
256
257static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
258 struct dm_crypt_request *dmreq)
259{
260 memset(iv, 0, cc->iv_size);
261 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
262
263 return 0;
264}
265
266/* Initialise ESSIV - compute salt but no local memory allocations */
267static int crypt_iv_essiv_init(struct crypt_config *cc)
268{
269 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
270 AHASH_REQUEST_ON_STACK(req, essiv->hash_tfm);
271 struct scatterlist sg;
272 struct crypto_cipher *essiv_tfm;
273 int err;
274
275 sg_init_one(&sg, cc->key, cc->key_size);
276 ahash_request_set_tfm(req, essiv->hash_tfm);
277 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
278 ahash_request_set_crypt(req, &sg, essiv->salt, cc->key_size);
279
280 err = crypto_ahash_digest(req);
281 ahash_request_zero(req);
282 if (err)
283 return err;
284
285 essiv_tfm = cc->iv_private;
286
287 err = crypto_cipher_setkey(essiv_tfm, essiv->salt,
288 crypto_ahash_digestsize(essiv->hash_tfm));
289 if (err)
290 return err;
291
292 return 0;
293}
294
295/* Wipe salt and reset key derived from volume key */
296static int crypt_iv_essiv_wipe(struct crypt_config *cc)
297{
298 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
299 unsigned salt_size = crypto_ahash_digestsize(essiv->hash_tfm);
300 struct crypto_cipher *essiv_tfm;
301 int r, err = 0;
302
303 memset(essiv->salt, 0, salt_size);
304
305 essiv_tfm = cc->iv_private;
306 r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size);
307 if (r)
308 err = r;
309
310 return err;
311}
312
313/* Set up per cpu cipher state */
314static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc,
315 struct dm_target *ti,
316 u8 *salt, unsigned saltsize)
317{
318 struct crypto_cipher *essiv_tfm;
319 int err;
320
321 /* Setup the essiv_tfm with the given salt */
322 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
323 if (IS_ERR(essiv_tfm)) {
324 ti->error = "Error allocating crypto tfm for ESSIV";
325 return essiv_tfm;
326 }
327
328 if (crypto_cipher_blocksize(essiv_tfm) !=
329 crypto_skcipher_ivsize(any_tfm(cc))) {
330 ti->error = "Block size of ESSIV cipher does "
331 "not match IV size of block cipher";
332 crypto_free_cipher(essiv_tfm);
333 return ERR_PTR(-EINVAL);
334 }
335
336 err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
337 if (err) {
338 ti->error = "Failed to set key for ESSIV cipher";
339 crypto_free_cipher(essiv_tfm);
340 return ERR_PTR(err);
341 }
342
343 return essiv_tfm;
344}
345
346static void crypt_iv_essiv_dtr(struct crypt_config *cc)
347{
348 struct crypto_cipher *essiv_tfm;
349 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
350
351 crypto_free_ahash(essiv->hash_tfm);
352 essiv->hash_tfm = NULL;
353
354 kzfree(essiv->salt);
355 essiv->salt = NULL;
356
357 essiv_tfm = cc->iv_private;
358
359 if (essiv_tfm)
360 crypto_free_cipher(essiv_tfm);
361
362 cc->iv_private = NULL;
363}
364
365static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
366 const char *opts)
367{
368 struct crypto_cipher *essiv_tfm = NULL;
369 struct crypto_ahash *hash_tfm = NULL;
370 u8 *salt = NULL;
371 int err;
372
373 if (!opts) {
374 ti->error = "Digest algorithm missing for ESSIV mode";
375 return -EINVAL;
376 }
377
378 /* Allocate hash algorithm */
379 hash_tfm = crypto_alloc_ahash(opts, 0, CRYPTO_ALG_ASYNC);
380 if (IS_ERR(hash_tfm)) {
381 ti->error = "Error initializing ESSIV hash";
382 err = PTR_ERR(hash_tfm);
383 goto bad;
384 }
385
386 salt = kzalloc(crypto_ahash_digestsize(hash_tfm), GFP_KERNEL);
387 if (!salt) {
388 ti->error = "Error kmallocing salt storage in ESSIV";
389 err = -ENOMEM;
390 goto bad;
391 }
392
393 cc->iv_gen_private.essiv.salt = salt;
394 cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
395
396 essiv_tfm = setup_essiv_cpu(cc, ti, salt,
397 crypto_ahash_digestsize(hash_tfm));
398 if (IS_ERR(essiv_tfm)) {
399 crypt_iv_essiv_dtr(cc);
400 return PTR_ERR(essiv_tfm);
401 }
402 cc->iv_private = essiv_tfm;
403
404 return 0;
405
406bad:
407 if (hash_tfm && !IS_ERR(hash_tfm))
408 crypto_free_ahash(hash_tfm);
409 kfree(salt);
410 return err;
411}
412
413static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv,
414 struct dm_crypt_request *dmreq)
415{
416 struct crypto_cipher *essiv_tfm = cc->iv_private;
417
418 memset(iv, 0, cc->iv_size);
419 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
420 crypto_cipher_encrypt_one(essiv_tfm, iv, iv);
421
422 return 0;
423}
424
425static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
426 const char *opts)
427{
428 unsigned bs = crypto_skcipher_blocksize(any_tfm(cc));
429 int log = ilog2(bs);
430
431 /* we need to calculate how far we must shift the sector count
432 * to get the cipher block count, we use this shift in _gen */
433
434 if (1 << log != bs) {
435 ti->error = "cypher blocksize is not a power of 2";
436 return -EINVAL;
437 }
438
439 if (log > 9) {
440 ti->error = "cypher blocksize is > 512";
441 return -EINVAL;
442 }
443
444 cc->iv_gen_private.benbi.shift = 9 - log;
445
446 return 0;
447}
448
449static void crypt_iv_benbi_dtr(struct crypt_config *cc)
450{
451}
452
453static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv,
454 struct dm_crypt_request *dmreq)
455{
456 __be64 val;
457
458 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
459
460 val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1);
461 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
462
463 return 0;
464}
465
466static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv,
467 struct dm_crypt_request *dmreq)
468{
469 memset(iv, 0, cc->iv_size);
470
471 return 0;
472}
473
474static void crypt_iv_lmk_dtr(struct crypt_config *cc)
475{
476 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
477
478 if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm))
479 crypto_free_shash(lmk->hash_tfm);
480 lmk->hash_tfm = NULL;
481
482 kzfree(lmk->seed);
483 lmk->seed = NULL;
484}
485
486static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti,
487 const char *opts)
488{
489 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
490
491 lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0);
492 if (IS_ERR(lmk->hash_tfm)) {
493 ti->error = "Error initializing LMK hash";
494 return PTR_ERR(lmk->hash_tfm);
495 }
496
497 /* No seed in LMK version 2 */
498 if (cc->key_parts == cc->tfms_count) {
499 lmk->seed = NULL;
500 return 0;
501 }
502
503 lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL);
504 if (!lmk->seed) {
505 crypt_iv_lmk_dtr(cc);
506 ti->error = "Error kmallocing seed storage in LMK";
507 return -ENOMEM;
508 }
509
510 return 0;
511}
512
513static int crypt_iv_lmk_init(struct crypt_config *cc)
514{
515 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
516 int subkey_size = cc->key_size / cc->key_parts;
517
518 /* LMK seed is on the position of LMK_KEYS + 1 key */
519 if (lmk->seed)
520 memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size),
521 crypto_shash_digestsize(lmk->hash_tfm));
522
523 return 0;
524}
525
526static int crypt_iv_lmk_wipe(struct crypt_config *cc)
527{
528 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
529
530 if (lmk->seed)
531 memset(lmk->seed, 0, LMK_SEED_SIZE);
532
533 return 0;
534}
535
536static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv,
537 struct dm_crypt_request *dmreq,
538 u8 *data)
539{
540 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
541 SHASH_DESC_ON_STACK(desc, lmk->hash_tfm);
542 struct md5_state md5state;
543 __le32 buf[4];
544 int i, r;
545
546 desc->tfm = lmk->hash_tfm;
547 desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
548
549 r = crypto_shash_init(desc);
550 if (r)
551 return r;
552
553 if (lmk->seed) {
554 r = crypto_shash_update(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(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(desc, (u8 *)buf, sizeof(buf));
570 if (r)
571 return r;
572
573 /* No MD5 padding here */
574 r = crypto_shash_export(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 void crypt_iv_tcw_dtr(struct crypt_config *cc)
622{
623 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
624
625 kzfree(tcw->iv_seed);
626 tcw->iv_seed = NULL;
627 kzfree(tcw->whitening);
628 tcw->whitening = NULL;
629
630 if (tcw->crc32_tfm && !IS_ERR(tcw->crc32_tfm))
631 crypto_free_shash(tcw->crc32_tfm);
632 tcw->crc32_tfm = NULL;
633}
634
635static int crypt_iv_tcw_ctr(struct crypt_config *cc, struct dm_target *ti,
636 const char *opts)
637{
638 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
639
640 if (cc->key_size <= (cc->iv_size + TCW_WHITENING_SIZE)) {
641 ti->error = "Wrong key size for TCW";
642 return -EINVAL;
643 }
644
645 tcw->crc32_tfm = crypto_alloc_shash("crc32", 0, 0);
646 if (IS_ERR(tcw->crc32_tfm)) {
647 ti->error = "Error initializing CRC32 in TCW";
648 return PTR_ERR(tcw->crc32_tfm);
649 }
650
651 tcw->iv_seed = kzalloc(cc->iv_size, GFP_KERNEL);
652 tcw->whitening = kzalloc(TCW_WHITENING_SIZE, GFP_KERNEL);
653 if (!tcw->iv_seed || !tcw->whitening) {
654 crypt_iv_tcw_dtr(cc);
655 ti->error = "Error allocating seed storage in TCW";
656 return -ENOMEM;
657 }
658
659 return 0;
660}
661
662static int crypt_iv_tcw_init(struct crypt_config *cc)
663{
664 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
665 int key_offset = cc->key_size - cc->iv_size - TCW_WHITENING_SIZE;
666
667 memcpy(tcw->iv_seed, &cc->key[key_offset], cc->iv_size);
668 memcpy(tcw->whitening, &cc->key[key_offset + cc->iv_size],
669 TCW_WHITENING_SIZE);
670
671 return 0;
672}
673
674static int crypt_iv_tcw_wipe(struct crypt_config *cc)
675{
676 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
677
678 memset(tcw->iv_seed, 0, cc->iv_size);
679 memset(tcw->whitening, 0, TCW_WHITENING_SIZE);
680
681 return 0;
682}
683
684static int crypt_iv_tcw_whitening(struct crypt_config *cc,
685 struct dm_crypt_request *dmreq,
686 u8 *data)
687{
688 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
689 __le64 sector = cpu_to_le64(dmreq->iv_sector);
690 u8 buf[TCW_WHITENING_SIZE];
691 SHASH_DESC_ON_STACK(desc, tcw->crc32_tfm);
692 int i, r;
693
694 /* xor whitening with sector number */
695 memcpy(buf, tcw->whitening, TCW_WHITENING_SIZE);
696 crypto_xor(buf, (u8 *)§or, 8);
697 crypto_xor(&buf[8], (u8 *)§or, 8);
698
699 /* calculate crc32 for every 32bit part and xor it */
700 desc->tfm = tcw->crc32_tfm;
701 desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
702 for (i = 0; i < 4; i++) {
703 r = crypto_shash_init(desc);
704 if (r)
705 goto out;
706 r = crypto_shash_update(desc, &buf[i * 4], 4);
707 if (r)
708 goto out;
709 r = crypto_shash_final(desc, &buf[i * 4]);
710 if (r)
711 goto out;
712 }
713 crypto_xor(&buf[0], &buf[12], 4);
714 crypto_xor(&buf[4], &buf[8], 4);
715
716 /* apply whitening (8 bytes) to whole sector */
717 for (i = 0; i < ((1 << SECTOR_SHIFT) / 8); i++)
718 crypto_xor(data + i * 8, buf, 8);
719out:
720 memzero_explicit(buf, sizeof(buf));
721 return r;
722}
723
724static int crypt_iv_tcw_gen(struct crypt_config *cc, u8 *iv,
725 struct dm_crypt_request *dmreq)
726{
727 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
728 __le64 sector = cpu_to_le64(dmreq->iv_sector);
729 u8 *src;
730 int r = 0;
731
732 /* Remove whitening from ciphertext */
733 if (bio_data_dir(dmreq->ctx->bio_in) != WRITE) {
734 src = kmap_atomic(sg_page(&dmreq->sg_in));
735 r = crypt_iv_tcw_whitening(cc, dmreq, src + dmreq->sg_in.offset);
736 kunmap_atomic(src);
737 }
738
739 /* Calculate IV */
740 memcpy(iv, tcw->iv_seed, cc->iv_size);
741 crypto_xor(iv, (u8 *)§or, 8);
742 if (cc->iv_size > 8)
743 crypto_xor(&iv[8], (u8 *)§or, cc->iv_size - 8);
744
745 return r;
746}
747
748static int crypt_iv_tcw_post(struct crypt_config *cc, u8 *iv,
749 struct dm_crypt_request *dmreq)
750{
751 u8 *dst;
752 int r;
753
754 if (bio_data_dir(dmreq->ctx->bio_in) != WRITE)
755 return 0;
756
757 /* Apply whitening on ciphertext */
758 dst = kmap_atomic(sg_page(&dmreq->sg_out));
759 r = crypt_iv_tcw_whitening(cc, dmreq, dst + dmreq->sg_out.offset);
760 kunmap_atomic(dst);
761
762 return r;
763}
764
765static const struct crypt_iv_operations crypt_iv_plain_ops = {
766 .generator = crypt_iv_plain_gen
767};
768
769static const struct crypt_iv_operations crypt_iv_plain64_ops = {
770 .generator = crypt_iv_plain64_gen
771};
772
773static const struct crypt_iv_operations crypt_iv_essiv_ops = {
774 .ctr = crypt_iv_essiv_ctr,
775 .dtr = crypt_iv_essiv_dtr,
776 .init = crypt_iv_essiv_init,
777 .wipe = crypt_iv_essiv_wipe,
778 .generator = crypt_iv_essiv_gen
779};
780
781static const struct crypt_iv_operations crypt_iv_benbi_ops = {
782 .ctr = crypt_iv_benbi_ctr,
783 .dtr = crypt_iv_benbi_dtr,
784 .generator = crypt_iv_benbi_gen
785};
786
787static const struct crypt_iv_operations crypt_iv_null_ops = {
788 .generator = crypt_iv_null_gen
789};
790
791static const struct crypt_iv_operations crypt_iv_lmk_ops = {
792 .ctr = crypt_iv_lmk_ctr,
793 .dtr = crypt_iv_lmk_dtr,
794 .init = crypt_iv_lmk_init,
795 .wipe = crypt_iv_lmk_wipe,
796 .generator = crypt_iv_lmk_gen,
797 .post = crypt_iv_lmk_post
798};
799
800static const struct crypt_iv_operations crypt_iv_tcw_ops = {
801 .ctr = crypt_iv_tcw_ctr,
802 .dtr = crypt_iv_tcw_dtr,
803 .init = crypt_iv_tcw_init,
804 .wipe = crypt_iv_tcw_wipe,
805 .generator = crypt_iv_tcw_gen,
806 .post = crypt_iv_tcw_post
807};
808
809static void crypt_convert_init(struct crypt_config *cc,
810 struct convert_context *ctx,
811 struct bio *bio_out, struct bio *bio_in,
812 sector_t sector)
813{
814 ctx->bio_in = bio_in;
815 ctx->bio_out = bio_out;
816 if (bio_in)
817 ctx->iter_in = bio_in->bi_iter;
818 if (bio_out)
819 ctx->iter_out = bio_out->bi_iter;
820 ctx->cc_sector = sector + cc->iv_offset;
821 init_completion(&ctx->restart);
822}
823
824static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
825 struct skcipher_request *req)
826{
827 return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
828}
829
830static struct skcipher_request *req_of_dmreq(struct crypt_config *cc,
831 struct dm_crypt_request *dmreq)
832{
833 return (struct skcipher_request *)((char *)dmreq - cc->dmreq_start);
834}
835
836static u8 *iv_of_dmreq(struct crypt_config *cc,
837 struct dm_crypt_request *dmreq)
838{
839 return (u8 *)ALIGN((unsigned long)(dmreq + 1),
840 crypto_skcipher_alignmask(any_tfm(cc)) + 1);
841}
842
843static int crypt_convert_block(struct crypt_config *cc,
844 struct convert_context *ctx,
845 struct skcipher_request *req)
846{
847 struct bio_vec bv_in = bio_iter_iovec(ctx->bio_in, ctx->iter_in);
848 struct bio_vec bv_out = bio_iter_iovec(ctx->bio_out, ctx->iter_out);
849 struct dm_crypt_request *dmreq;
850 u8 *iv;
851 int r;
852
853 dmreq = dmreq_of_req(cc, req);
854 iv = iv_of_dmreq(cc, dmreq);
855
856 dmreq->iv_sector = ctx->cc_sector;
857 dmreq->ctx = ctx;
858 sg_init_table(&dmreq->sg_in, 1);
859 sg_set_page(&dmreq->sg_in, bv_in.bv_page, 1 << SECTOR_SHIFT,
860 bv_in.bv_offset);
861
862 sg_init_table(&dmreq->sg_out, 1);
863 sg_set_page(&dmreq->sg_out, bv_out.bv_page, 1 << SECTOR_SHIFT,
864 bv_out.bv_offset);
865
866 bio_advance_iter(ctx->bio_in, &ctx->iter_in, 1 << SECTOR_SHIFT);
867 bio_advance_iter(ctx->bio_out, &ctx->iter_out, 1 << SECTOR_SHIFT);
868
869 if (cc->iv_gen_ops) {
870 r = cc->iv_gen_ops->generator(cc, iv, dmreq);
871 if (r < 0)
872 return r;
873 }
874
875 skcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
876 1 << SECTOR_SHIFT, iv);
877
878 if (bio_data_dir(ctx->bio_in) == WRITE)
879 r = crypto_skcipher_encrypt(req);
880 else
881 r = crypto_skcipher_decrypt(req);
882
883 if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
884 r = cc->iv_gen_ops->post(cc, iv, dmreq);
885
886 return r;
887}
888
889static void kcryptd_async_done(struct crypto_async_request *async_req,
890 int error);
891
892static void crypt_alloc_req(struct crypt_config *cc,
893 struct convert_context *ctx)
894{
895 unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1);
896
897 if (!ctx->req)
898 ctx->req = mempool_alloc(cc->req_pool, GFP_NOIO);
899
900 skcipher_request_set_tfm(ctx->req, cc->tfms[key_index]);
901
902 /*
903 * Use REQ_MAY_BACKLOG so a cipher driver internally backlogs
904 * requests if driver request queue is full.
905 */
906 skcipher_request_set_callback(ctx->req,
907 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
908 kcryptd_async_done, dmreq_of_req(cc, ctx->req));
909}
910
911static void crypt_free_req(struct crypt_config *cc,
912 struct skcipher_request *req, struct bio *base_bio)
913{
914 struct dm_crypt_io *io = dm_per_bio_data(base_bio, cc->per_bio_data_size);
915
916 if ((struct skcipher_request *)(io + 1) != req)
917 mempool_free(req, cc->req_pool);
918}
919
920/*
921 * Encrypt / decrypt data from one bio to another one (can be the same one)
922 */
923static int crypt_convert(struct crypt_config *cc,
924 struct convert_context *ctx)
925{
926 int r;
927
928 atomic_set(&ctx->cc_pending, 1);
929
930 while (ctx->iter_in.bi_size && ctx->iter_out.bi_size) {
931
932 crypt_alloc_req(cc, ctx);
933
934 atomic_inc(&ctx->cc_pending);
935
936 r = crypt_convert_block(cc, ctx, ctx->req);
937
938 switch (r) {
939 /*
940 * The request was queued by a crypto driver
941 * but the driver request queue is full, let's wait.
942 */
943 case -EBUSY:
944 wait_for_completion(&ctx->restart);
945 reinit_completion(&ctx->restart);
946 /* fall through */
947 /*
948 * The request is queued and processed asynchronously,
949 * completion function kcryptd_async_done() will be called.
950 */
951 case -EINPROGRESS:
952 ctx->req = NULL;
953 ctx->cc_sector++;
954 continue;
955 /*
956 * The request was already processed (synchronously).
957 */
958 case 0:
959 atomic_dec(&ctx->cc_pending);
960 ctx->cc_sector++;
961 cond_resched();
962 continue;
963
964 /* There was an error while processing the request. */
965 default:
966 atomic_dec(&ctx->cc_pending);
967 return r;
968 }
969 }
970
971 return 0;
972}
973
974static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone);
975
976/*
977 * Generate a new unfragmented bio with the given size
978 * This should never violate the device limitations (but only because
979 * max_segment_size is being constrained to PAGE_SIZE).
980 *
981 * This function may be called concurrently. If we allocate from the mempool
982 * concurrently, there is a possibility of deadlock. For example, if we have
983 * mempool of 256 pages, two processes, each wanting 256, pages allocate from
984 * the mempool concurrently, it may deadlock in a situation where both processes
985 * have allocated 128 pages and the mempool is exhausted.
986 *
987 * In order to avoid this scenario we allocate the pages under a mutex.
988 *
989 * In order to not degrade performance with excessive locking, we try
990 * non-blocking allocations without a mutex first but on failure we fallback
991 * to blocking allocations with a mutex.
992 */
993static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
994{
995 struct crypt_config *cc = io->cc;
996 struct bio *clone;
997 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
998 gfp_t gfp_mask = GFP_NOWAIT | __GFP_HIGHMEM;
999 unsigned i, len, remaining_size;
1000 struct page *page;
1001
1002retry:
1003 if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM))
1004 mutex_lock(&cc->bio_alloc_lock);
1005
1006 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
1007 if (!clone)
1008 goto return_clone;
1009
1010 clone_init(io, clone);
1011
1012 remaining_size = size;
1013
1014 for (i = 0; i < nr_iovecs; i++) {
1015 page = mempool_alloc(cc->page_pool, gfp_mask);
1016 if (!page) {
1017 crypt_free_buffer_pages(cc, clone);
1018 bio_put(clone);
1019 gfp_mask |= __GFP_DIRECT_RECLAIM;
1020 goto retry;
1021 }
1022
1023 len = (remaining_size > PAGE_SIZE) ? PAGE_SIZE : remaining_size;
1024
1025 bio_add_page(clone, page, len, 0);
1026
1027 remaining_size -= len;
1028 }
1029
1030return_clone:
1031 if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM))
1032 mutex_unlock(&cc->bio_alloc_lock);
1033
1034 return clone;
1035}
1036
1037static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
1038{
1039 unsigned int i;
1040 struct bio_vec *bv;
1041
1042 bio_for_each_segment_all(bv, clone, i) {
1043 BUG_ON(!bv->bv_page);
1044 mempool_free(bv->bv_page, cc->page_pool);
1045 bv->bv_page = NULL;
1046 }
1047}
1048
1049static void crypt_io_init(struct dm_crypt_io *io, struct crypt_config *cc,
1050 struct bio *bio, sector_t sector)
1051{
1052 io->cc = cc;
1053 io->base_bio = bio;
1054 io->sector = sector;
1055 io->error = 0;
1056 io->ctx.req = NULL;
1057 atomic_set(&io->io_pending, 0);
1058}
1059
1060static void crypt_inc_pending(struct dm_crypt_io *io)
1061{
1062 atomic_inc(&io->io_pending);
1063}
1064
1065/*
1066 * One of the bios was finished. Check for completion of
1067 * the whole request and correctly clean up the buffer.
1068 */
1069static void crypt_dec_pending(struct dm_crypt_io *io)
1070{
1071 struct crypt_config *cc = io->cc;
1072 struct bio *base_bio = io->base_bio;
1073 int error = io->error;
1074
1075 if (!atomic_dec_and_test(&io->io_pending))
1076 return;
1077
1078 if (io->ctx.req)
1079 crypt_free_req(cc, io->ctx.req, base_bio);
1080
1081 base_bio->bi_error = error;
1082 bio_endio(base_bio);
1083}
1084
1085/*
1086 * kcryptd/kcryptd_io:
1087 *
1088 * Needed because it would be very unwise to do decryption in an
1089 * interrupt context.
1090 *
1091 * kcryptd performs the actual encryption or decryption.
1092 *
1093 * kcryptd_io performs the IO submission.
1094 *
1095 * They must be separated as otherwise the final stages could be
1096 * starved by new requests which can block in the first stages due
1097 * to memory allocation.
1098 *
1099 * The work is done per CPU global for all dm-crypt instances.
1100 * They should not depend on each other and do not block.
1101 */
1102static void crypt_endio(struct bio *clone)
1103{
1104 struct dm_crypt_io *io = clone->bi_private;
1105 struct crypt_config *cc = io->cc;
1106 unsigned rw = bio_data_dir(clone);
1107 int error;
1108
1109 /*
1110 * free the processed pages
1111 */
1112 if (rw == WRITE)
1113 crypt_free_buffer_pages(cc, clone);
1114
1115 error = clone->bi_error;
1116 bio_put(clone);
1117
1118 if (rw == READ && !error) {
1119 kcryptd_queue_crypt(io);
1120 return;
1121 }
1122
1123 if (unlikely(error))
1124 io->error = error;
1125
1126 crypt_dec_pending(io);
1127}
1128
1129static void clone_init(struct dm_crypt_io *io, struct bio *clone)
1130{
1131 struct crypt_config *cc = io->cc;
1132
1133 clone->bi_private = io;
1134 clone->bi_end_io = crypt_endio;
1135 clone->bi_bdev = cc->dev->bdev;
1136 clone->bi_opf = io->base_bio->bi_opf;
1137}
1138
1139static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
1140{
1141 struct crypt_config *cc = io->cc;
1142 struct bio *clone;
1143
1144 /*
1145 * We need the original biovec array in order to decrypt
1146 * the whole bio data *afterwards* -- thanks to immutable
1147 * biovecs we don't need to worry about the block layer
1148 * modifying the biovec array; so leverage bio_clone_fast().
1149 */
1150 clone = bio_clone_fast(io->base_bio, gfp, cc->bs);
1151 if (!clone)
1152 return 1;
1153
1154 crypt_inc_pending(io);
1155
1156 clone_init(io, clone);
1157 clone->bi_iter.bi_sector = cc->start + io->sector;
1158
1159 generic_make_request(clone);
1160 return 0;
1161}
1162
1163static void kcryptd_io_read_work(struct work_struct *work)
1164{
1165 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1166
1167 crypt_inc_pending(io);
1168 if (kcryptd_io_read(io, GFP_NOIO))
1169 io->error = -ENOMEM;
1170 crypt_dec_pending(io);
1171}
1172
1173static void kcryptd_queue_read(struct dm_crypt_io *io)
1174{
1175 struct crypt_config *cc = io->cc;
1176
1177 INIT_WORK(&io->work, kcryptd_io_read_work);
1178 queue_work(cc->io_queue, &io->work);
1179}
1180
1181static void kcryptd_io_write(struct dm_crypt_io *io)
1182{
1183 struct bio *clone = io->ctx.bio_out;
1184
1185 generic_make_request(clone);
1186}
1187
1188#define crypt_io_from_node(node) rb_entry((node), struct dm_crypt_io, rb_node)
1189
1190static int dmcrypt_write(void *data)
1191{
1192 struct crypt_config *cc = data;
1193 struct dm_crypt_io *io;
1194
1195 while (1) {
1196 struct rb_root write_tree;
1197 struct blk_plug plug;
1198
1199 DECLARE_WAITQUEUE(wait, current);
1200
1201 spin_lock_irq(&cc->write_thread_wait.lock);
1202continue_locked:
1203
1204 if (!RB_EMPTY_ROOT(&cc->write_tree))
1205 goto pop_from_list;
1206
1207 set_current_state(TASK_INTERRUPTIBLE);
1208 __add_wait_queue(&cc->write_thread_wait, &wait);
1209
1210 spin_unlock_irq(&cc->write_thread_wait.lock);
1211
1212 if (unlikely(kthread_should_stop())) {
1213 set_task_state(current, TASK_RUNNING);
1214 remove_wait_queue(&cc->write_thread_wait, &wait);
1215 break;
1216 }
1217
1218 schedule();
1219
1220 set_task_state(current, TASK_RUNNING);
1221 spin_lock_irq(&cc->write_thread_wait.lock);
1222 __remove_wait_queue(&cc->write_thread_wait, &wait);
1223 goto continue_locked;
1224
1225pop_from_list:
1226 write_tree = cc->write_tree;
1227 cc->write_tree = RB_ROOT;
1228 spin_unlock_irq(&cc->write_thread_wait.lock);
1229
1230 BUG_ON(rb_parent(write_tree.rb_node));
1231
1232 /*
1233 * Note: we cannot walk the tree here with rb_next because
1234 * the structures may be freed when kcryptd_io_write is called.
1235 */
1236 blk_start_plug(&plug);
1237 do {
1238 io = crypt_io_from_node(rb_first(&write_tree));
1239 rb_erase(&io->rb_node, &write_tree);
1240 kcryptd_io_write(io);
1241 } while (!RB_EMPTY_ROOT(&write_tree));
1242 blk_finish_plug(&plug);
1243 }
1244 return 0;
1245}
1246
1247static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
1248{
1249 struct bio *clone = io->ctx.bio_out;
1250 struct crypt_config *cc = io->cc;
1251 unsigned long flags;
1252 sector_t sector;
1253 struct rb_node **rbp, *parent;
1254
1255 if (unlikely(io->error < 0)) {
1256 crypt_free_buffer_pages(cc, clone);
1257 bio_put(clone);
1258 crypt_dec_pending(io);
1259 return;
1260 }
1261
1262 /* crypt_convert should have filled the clone bio */
1263 BUG_ON(io->ctx.iter_out.bi_size);
1264
1265 clone->bi_iter.bi_sector = cc->start + io->sector;
1266
1267 if (likely(!async) && test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) {
1268 generic_make_request(clone);
1269 return;
1270 }
1271
1272 spin_lock_irqsave(&cc->write_thread_wait.lock, flags);
1273 rbp = &cc->write_tree.rb_node;
1274 parent = NULL;
1275 sector = io->sector;
1276 while (*rbp) {
1277 parent = *rbp;
1278 if (sector < crypt_io_from_node(parent)->sector)
1279 rbp = &(*rbp)->rb_left;
1280 else
1281 rbp = &(*rbp)->rb_right;
1282 }
1283 rb_link_node(&io->rb_node, parent, rbp);
1284 rb_insert_color(&io->rb_node, &cc->write_tree);
1285
1286 wake_up_locked(&cc->write_thread_wait);
1287 spin_unlock_irqrestore(&cc->write_thread_wait.lock, flags);
1288}
1289
1290static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
1291{
1292 struct crypt_config *cc = io->cc;
1293 struct bio *clone;
1294 int crypt_finished;
1295 sector_t sector = io->sector;
1296 int r;
1297
1298 /*
1299 * Prevent io from disappearing until this function completes.
1300 */
1301 crypt_inc_pending(io);
1302 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
1303
1304 clone = crypt_alloc_buffer(io, io->base_bio->bi_iter.bi_size);
1305 if (unlikely(!clone)) {
1306 io->error = -EIO;
1307 goto dec;
1308 }
1309
1310 io->ctx.bio_out = clone;
1311 io->ctx.iter_out = clone->bi_iter;
1312
1313 sector += bio_sectors(clone);
1314
1315 crypt_inc_pending(io);
1316 r = crypt_convert(cc, &io->ctx);
1317 if (r)
1318 io->error = -EIO;
1319 crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending);
1320
1321 /* Encryption was already finished, submit io now */
1322 if (crypt_finished) {
1323 kcryptd_crypt_write_io_submit(io, 0);
1324 io->sector = sector;
1325 }
1326
1327dec:
1328 crypt_dec_pending(io);
1329}
1330
1331static void kcryptd_crypt_read_done(struct dm_crypt_io *io)
1332{
1333 crypt_dec_pending(io);
1334}
1335
1336static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
1337{
1338 struct crypt_config *cc = io->cc;
1339 int r = 0;
1340
1341 crypt_inc_pending(io);
1342
1343 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
1344 io->sector);
1345
1346 r = crypt_convert(cc, &io->ctx);
1347 if (r < 0)
1348 io->error = -EIO;
1349
1350 if (atomic_dec_and_test(&io->ctx.cc_pending))
1351 kcryptd_crypt_read_done(io);
1352
1353 crypt_dec_pending(io);
1354}
1355
1356static void kcryptd_async_done(struct crypto_async_request *async_req,
1357 int error)
1358{
1359 struct dm_crypt_request *dmreq = async_req->data;
1360 struct convert_context *ctx = dmreq->ctx;
1361 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
1362 struct crypt_config *cc = io->cc;
1363
1364 /*
1365 * A request from crypto driver backlog is going to be processed now,
1366 * finish the completion and continue in crypt_convert().
1367 * (Callback will be called for the second time for this request.)
1368 */
1369 if (error == -EINPROGRESS) {
1370 complete(&ctx->restart);
1371 return;
1372 }
1373
1374 if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
1375 error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
1376
1377 if (error < 0)
1378 io->error = -EIO;
1379
1380 crypt_free_req(cc, req_of_dmreq(cc, dmreq), io->base_bio);
1381
1382 if (!atomic_dec_and_test(&ctx->cc_pending))
1383 return;
1384
1385 if (bio_data_dir(io->base_bio) == READ)
1386 kcryptd_crypt_read_done(io);
1387 else
1388 kcryptd_crypt_write_io_submit(io, 1);
1389}
1390
1391static void kcryptd_crypt(struct work_struct *work)
1392{
1393 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1394
1395 if (bio_data_dir(io->base_bio) == READ)
1396 kcryptd_crypt_read_convert(io);
1397 else
1398 kcryptd_crypt_write_convert(io);
1399}
1400
1401static void kcryptd_queue_crypt(struct dm_crypt_io *io)
1402{
1403 struct crypt_config *cc = io->cc;
1404
1405 INIT_WORK(&io->work, kcryptd_crypt);
1406 queue_work(cc->crypt_queue, &io->work);
1407}
1408
1409/*
1410 * Decode key from its hex representation
1411 */
1412static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
1413{
1414 char buffer[3];
1415 unsigned int i;
1416
1417 buffer[2] = '\0';
1418
1419 for (i = 0; i < size; i++) {
1420 buffer[0] = *hex++;
1421 buffer[1] = *hex++;
1422
1423 if (kstrtou8(buffer, 16, &key[i]))
1424 return -EINVAL;
1425 }
1426
1427 if (*hex != '\0')
1428 return -EINVAL;
1429
1430 return 0;
1431}
1432
1433static void crypt_free_tfms(struct crypt_config *cc)
1434{
1435 unsigned i;
1436
1437 if (!cc->tfms)
1438 return;
1439
1440 for (i = 0; i < cc->tfms_count; i++)
1441 if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) {
1442 crypto_free_skcipher(cc->tfms[i]);
1443 cc->tfms[i] = NULL;
1444 }
1445
1446 kfree(cc->tfms);
1447 cc->tfms = NULL;
1448}
1449
1450static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode)
1451{
1452 unsigned i;
1453 int err;
1454
1455 cc->tfms = kzalloc(cc->tfms_count * sizeof(struct crypto_skcipher *),
1456 GFP_KERNEL);
1457 if (!cc->tfms)
1458 return -ENOMEM;
1459
1460 for (i = 0; i < cc->tfms_count; i++) {
1461 cc->tfms[i] = crypto_alloc_skcipher(ciphermode, 0, 0);
1462 if (IS_ERR(cc->tfms[i])) {
1463 err = PTR_ERR(cc->tfms[i]);
1464 crypt_free_tfms(cc);
1465 return err;
1466 }
1467 }
1468
1469 return 0;
1470}
1471
1472static int crypt_setkey(struct crypt_config *cc)
1473{
1474 unsigned subkey_size;
1475 int err = 0, i, r;
1476
1477 /* Ignore extra keys (which are used for IV etc) */
1478 subkey_size = (cc->key_size - cc->key_extra_size) >> ilog2(cc->tfms_count);
1479
1480 for (i = 0; i < cc->tfms_count; i++) {
1481 r = crypto_skcipher_setkey(cc->tfms[i],
1482 cc->key + (i * subkey_size),
1483 subkey_size);
1484 if (r)
1485 err = r;
1486 }
1487
1488 return err;
1489}
1490
1491#ifdef CONFIG_KEYS
1492
1493static bool contains_whitespace(const char *str)
1494{
1495 while (*str)
1496 if (isspace(*str++))
1497 return true;
1498 return false;
1499}
1500
1501static int crypt_set_keyring_key(struct crypt_config *cc, const char *key_string)
1502{
1503 char *new_key_string, *key_desc;
1504 int ret;
1505 struct key *key;
1506 const struct user_key_payload *ukp;
1507
1508 /*
1509 * Reject key_string with whitespace. dm core currently lacks code for
1510 * proper whitespace escaping in arguments on DM_TABLE_STATUS path.
1511 */
1512 if (contains_whitespace(key_string)) {
1513 DMERR("whitespace chars not allowed in key string");
1514 return -EINVAL;
1515 }
1516
1517 /* look for next ':' separating key_type from key_description */
1518 key_desc = strpbrk(key_string, ":");
1519 if (!key_desc || key_desc == key_string || !strlen(key_desc + 1))
1520 return -EINVAL;
1521
1522 if (strncmp(key_string, "logon:", key_desc - key_string + 1) &&
1523 strncmp(key_string, "user:", key_desc - key_string + 1))
1524 return -EINVAL;
1525
1526 new_key_string = kstrdup(key_string, GFP_KERNEL);
1527 if (!new_key_string)
1528 return -ENOMEM;
1529
1530 key = request_key(key_string[0] == 'l' ? &key_type_logon : &key_type_user,
1531 key_desc + 1, NULL);
1532 if (IS_ERR(key)) {
1533 kzfree(new_key_string);
1534 return PTR_ERR(key);
1535 }
1536
1537 down_read(&key->sem);
1538
1539 ukp = user_key_payload(key);
1540 if (!ukp) {
1541 up_read(&key->sem);
1542 key_put(key);
1543 kzfree(new_key_string);
1544 return -EKEYREVOKED;
1545 }
1546
1547 if (cc->key_size != ukp->datalen) {
1548 up_read(&key->sem);
1549 key_put(key);
1550 kzfree(new_key_string);
1551 return -EINVAL;
1552 }
1553
1554 memcpy(cc->key, ukp->data, cc->key_size);
1555
1556 up_read(&key->sem);
1557 key_put(key);
1558
1559 /* clear the flag since following operations may invalidate previously valid key */
1560 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1561
1562 ret = crypt_setkey(cc);
1563
1564 /* wipe the kernel key payload copy in each case */
1565 memset(cc->key, 0, cc->key_size * sizeof(u8));
1566
1567 if (!ret) {
1568 set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1569 kzfree(cc->key_string);
1570 cc->key_string = new_key_string;
1571 } else
1572 kzfree(new_key_string);
1573
1574 return ret;
1575}
1576
1577static int get_key_size(char **key_string)
1578{
1579 char *colon, dummy;
1580 int ret;
1581
1582 if (*key_string[0] != ':')
1583 return strlen(*key_string) >> 1;
1584
1585 /* look for next ':' in key string */
1586 colon = strpbrk(*key_string + 1, ":");
1587 if (!colon)
1588 return -EINVAL;
1589
1590 if (sscanf(*key_string + 1, "%u%c", &ret, &dummy) != 2 || dummy != ':')
1591 return -EINVAL;
1592
1593 *key_string = colon;
1594
1595 /* remaining key string should be :<logon|user>:<key_desc> */
1596
1597 return ret;
1598}
1599
1600#else
1601
1602static int crypt_set_keyring_key(struct crypt_config *cc, const char *key_string)
1603{
1604 return -EINVAL;
1605}
1606
1607static int get_key_size(char **key_string)
1608{
1609 return (*key_string[0] == ':') ? -EINVAL : strlen(*key_string) >> 1;
1610}
1611
1612#endif
1613
1614static int crypt_set_key(struct crypt_config *cc, char *key)
1615{
1616 int r = -EINVAL;
1617 int key_string_len = strlen(key);
1618
1619 /* Hyphen (which gives a key_size of zero) means there is no key. */
1620 if (!cc->key_size && strcmp(key, "-"))
1621 goto out;
1622
1623 /* ':' means the key is in kernel keyring, short-circuit normal key processing */
1624 if (key[0] == ':') {
1625 r = crypt_set_keyring_key(cc, key + 1);
1626 goto out;
1627 }
1628
1629 /* clear the flag since following operations may invalidate previously valid key */
1630 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1631
1632 /* wipe references to any kernel keyring key */
1633 kzfree(cc->key_string);
1634 cc->key_string = NULL;
1635
1636 if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
1637 goto out;
1638
1639 r = crypt_setkey(cc);
1640 if (!r)
1641 set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1642
1643out:
1644 /* Hex key string not needed after here, so wipe it. */
1645 memset(key, '0', key_string_len);
1646
1647 return r;
1648}
1649
1650static int crypt_wipe_key(struct crypt_config *cc)
1651{
1652 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1653 memset(&cc->key, 0, cc->key_size * sizeof(u8));
1654 kzfree(cc->key_string);
1655 cc->key_string = NULL;
1656
1657 return crypt_setkey(cc);
1658}
1659
1660static void crypt_dtr(struct dm_target *ti)
1661{
1662 struct crypt_config *cc = ti->private;
1663
1664 ti->private = NULL;
1665
1666 if (!cc)
1667 return;
1668
1669 if (cc->write_thread)
1670 kthread_stop(cc->write_thread);
1671
1672 if (cc->io_queue)
1673 destroy_workqueue(cc->io_queue);
1674 if (cc->crypt_queue)
1675 destroy_workqueue(cc->crypt_queue);
1676
1677 crypt_free_tfms(cc);
1678
1679 if (cc->bs)
1680 bioset_free(cc->bs);
1681
1682 mempool_destroy(cc->page_pool);
1683 mempool_destroy(cc->req_pool);
1684
1685 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1686 cc->iv_gen_ops->dtr(cc);
1687
1688 if (cc->dev)
1689 dm_put_device(ti, cc->dev);
1690
1691 kzfree(cc->cipher);
1692 kzfree(cc->cipher_string);
1693 kzfree(cc->key_string);
1694
1695 /* Must zero key material before freeing */
1696 kzfree(cc);
1697}
1698
1699static int crypt_ctr_cipher(struct dm_target *ti,
1700 char *cipher_in, char *key)
1701{
1702 struct crypt_config *cc = ti->private;
1703 char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount;
1704 char *cipher_api = NULL;
1705 int ret = -EINVAL;
1706 char dummy;
1707
1708 /* Convert to crypto api definition? */
1709 if (strchr(cipher_in, '(')) {
1710 ti->error = "Bad cipher specification";
1711 return -EINVAL;
1712 }
1713
1714 cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
1715 if (!cc->cipher_string)
1716 goto bad_mem;
1717
1718 /*
1719 * Legacy dm-crypt cipher specification
1720 * cipher[:keycount]-mode-iv:ivopts
1721 */
1722 tmp = cipher_in;
1723 keycount = strsep(&tmp, "-");
1724 cipher = strsep(&keycount, ":");
1725
1726 if (!keycount)
1727 cc->tfms_count = 1;
1728 else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 ||
1729 !is_power_of_2(cc->tfms_count)) {
1730 ti->error = "Bad cipher key count specification";
1731 return -EINVAL;
1732 }
1733 cc->key_parts = cc->tfms_count;
1734 cc->key_extra_size = 0;
1735
1736 cc->cipher = kstrdup(cipher, GFP_KERNEL);
1737 if (!cc->cipher)
1738 goto bad_mem;
1739
1740 chainmode = strsep(&tmp, "-");
1741 ivopts = strsep(&tmp, "-");
1742 ivmode = strsep(&ivopts, ":");
1743
1744 if (tmp)
1745 DMWARN("Ignoring unexpected additional cipher options");
1746
1747 /*
1748 * For compatibility with the original dm-crypt mapping format, if
1749 * only the cipher name is supplied, use cbc-plain.
1750 */
1751 if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
1752 chainmode = "cbc";
1753 ivmode = "plain";
1754 }
1755
1756 if (strcmp(chainmode, "ecb") && !ivmode) {
1757 ti->error = "IV mechanism required";
1758 return -EINVAL;
1759 }
1760
1761 cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
1762 if (!cipher_api)
1763 goto bad_mem;
1764
1765 ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
1766 "%s(%s)", chainmode, cipher);
1767 if (ret < 0) {
1768 kfree(cipher_api);
1769 goto bad_mem;
1770 }
1771
1772 /* Allocate cipher */
1773 ret = crypt_alloc_tfms(cc, cipher_api);
1774 if (ret < 0) {
1775 ti->error = "Error allocating crypto tfm";
1776 goto bad;
1777 }
1778
1779 /* Initialize IV */
1780 cc->iv_size = crypto_skcipher_ivsize(any_tfm(cc));
1781 if (cc->iv_size)
1782 /* at least a 64 bit sector number should fit in our buffer */
1783 cc->iv_size = max(cc->iv_size,
1784 (unsigned int)(sizeof(u64) / sizeof(u8)));
1785 else if (ivmode) {
1786 DMWARN("Selected cipher does not support IVs");
1787 ivmode = NULL;
1788 }
1789
1790 /* Choose ivmode, see comments at iv code. */
1791 if (ivmode == NULL)
1792 cc->iv_gen_ops = NULL;
1793 else if (strcmp(ivmode, "plain") == 0)
1794 cc->iv_gen_ops = &crypt_iv_plain_ops;
1795 else if (strcmp(ivmode, "plain64") == 0)
1796 cc->iv_gen_ops = &crypt_iv_plain64_ops;
1797 else if (strcmp(ivmode, "essiv") == 0)
1798 cc->iv_gen_ops = &crypt_iv_essiv_ops;
1799 else if (strcmp(ivmode, "benbi") == 0)
1800 cc->iv_gen_ops = &crypt_iv_benbi_ops;
1801 else if (strcmp(ivmode, "null") == 0)
1802 cc->iv_gen_ops = &crypt_iv_null_ops;
1803 else if (strcmp(ivmode, "lmk") == 0) {
1804 cc->iv_gen_ops = &crypt_iv_lmk_ops;
1805 /*
1806 * Version 2 and 3 is recognised according
1807 * to length of provided multi-key string.
1808 * If present (version 3), last key is used as IV seed.
1809 * All keys (including IV seed) are always the same size.
1810 */
1811 if (cc->key_size % cc->key_parts) {
1812 cc->key_parts++;
1813 cc->key_extra_size = cc->key_size / cc->key_parts;
1814 }
1815 } else if (strcmp(ivmode, "tcw") == 0) {
1816 cc->iv_gen_ops = &crypt_iv_tcw_ops;
1817 cc->key_parts += 2; /* IV + whitening */
1818 cc->key_extra_size = cc->iv_size + TCW_WHITENING_SIZE;
1819 } else {
1820 ret = -EINVAL;
1821 ti->error = "Invalid IV mode";
1822 goto bad;
1823 }
1824
1825 /* Initialize and set key */
1826 ret = crypt_set_key(cc, key);
1827 if (ret < 0) {
1828 ti->error = "Error decoding and setting key";
1829 goto bad;
1830 }
1831
1832 /* Allocate IV */
1833 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
1834 ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
1835 if (ret < 0) {
1836 ti->error = "Error creating IV";
1837 goto bad;
1838 }
1839 }
1840
1841 /* Initialize IV (set keys for ESSIV etc) */
1842 if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
1843 ret = cc->iv_gen_ops->init(cc);
1844 if (ret < 0) {
1845 ti->error = "Error initialising IV";
1846 goto bad;
1847 }
1848 }
1849
1850 ret = 0;
1851bad:
1852 kfree(cipher_api);
1853 return ret;
1854
1855bad_mem:
1856 ti->error = "Cannot allocate cipher strings";
1857 return -ENOMEM;
1858}
1859
1860/*
1861 * Construct an encryption mapping:
1862 * <cipher> [<key>|:<key_size>:<user|logon>:<key_description>] <iv_offset> <dev_path> <start>
1863 */
1864static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1865{
1866 struct crypt_config *cc;
1867 int key_size;
1868 unsigned int opt_params;
1869 unsigned long long tmpll;
1870 int ret;
1871 size_t iv_size_padding;
1872 struct dm_arg_set as;
1873 const char *opt_string;
1874 char dummy;
1875
1876 static struct dm_arg _args[] = {
1877 {0, 3, "Invalid number of feature args"},
1878 };
1879
1880 if (argc < 5) {
1881 ti->error = "Not enough arguments";
1882 return -EINVAL;
1883 }
1884
1885 key_size = get_key_size(&argv[1]);
1886 if (key_size < 0) {
1887 ti->error = "Cannot parse key size";
1888 return -EINVAL;
1889 }
1890
1891 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
1892 if (!cc) {
1893 ti->error = "Cannot allocate encryption context";
1894 return -ENOMEM;
1895 }
1896 cc->key_size = key_size;
1897
1898 ti->private = cc;
1899 ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
1900 if (ret < 0)
1901 goto bad;
1902
1903 cc->dmreq_start = sizeof(struct skcipher_request);
1904 cc->dmreq_start += crypto_skcipher_reqsize(any_tfm(cc));
1905 cc->dmreq_start = ALIGN(cc->dmreq_start, __alignof__(struct dm_crypt_request));
1906
1907 if (crypto_skcipher_alignmask(any_tfm(cc)) < CRYPTO_MINALIGN) {
1908 /* Allocate the padding exactly */
1909 iv_size_padding = -(cc->dmreq_start + sizeof(struct dm_crypt_request))
1910 & crypto_skcipher_alignmask(any_tfm(cc));
1911 } else {
1912 /*
1913 * If the cipher requires greater alignment than kmalloc
1914 * alignment, we don't know the exact position of the
1915 * initialization vector. We must assume worst case.
1916 */
1917 iv_size_padding = crypto_skcipher_alignmask(any_tfm(cc));
1918 }
1919
1920 ret = -ENOMEM;
1921 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1922 sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size);
1923 if (!cc->req_pool) {
1924 ti->error = "Cannot allocate crypt request mempool";
1925 goto bad;
1926 }
1927
1928 cc->per_bio_data_size = ti->per_io_data_size =
1929 ALIGN(sizeof(struct dm_crypt_io) + cc->dmreq_start +
1930 sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size,
1931 ARCH_KMALLOC_MINALIGN);
1932
1933 cc->page_pool = mempool_create_page_pool(BIO_MAX_PAGES, 0);
1934 if (!cc->page_pool) {
1935 ti->error = "Cannot allocate page mempool";
1936 goto bad;
1937 }
1938
1939 cc->bs = bioset_create(MIN_IOS, 0);
1940 if (!cc->bs) {
1941 ti->error = "Cannot allocate crypt bioset";
1942 goto bad;
1943 }
1944
1945 mutex_init(&cc->bio_alloc_lock);
1946
1947 ret = -EINVAL;
1948 if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) {
1949 ti->error = "Invalid iv_offset sector";
1950 goto bad;
1951 }
1952 cc->iv_offset = tmpll;
1953
1954 ret = dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev);
1955 if (ret) {
1956 ti->error = "Device lookup failed";
1957 goto bad;
1958 }
1959
1960 ret = -EINVAL;
1961 if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
1962 ti->error = "Invalid device sector";
1963 goto bad;
1964 }
1965 cc->start = tmpll;
1966
1967 argv += 5;
1968 argc -= 5;
1969
1970 /* Optional parameters */
1971 if (argc) {
1972 as.argc = argc;
1973 as.argv = argv;
1974
1975 ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1976 if (ret)
1977 goto bad;
1978
1979 ret = -EINVAL;
1980 while (opt_params--) {
1981 opt_string = dm_shift_arg(&as);
1982 if (!opt_string) {
1983 ti->error = "Not enough feature arguments";
1984 goto bad;
1985 }
1986
1987 if (!strcasecmp(opt_string, "allow_discards"))
1988 ti->num_discard_bios = 1;
1989
1990 else if (!strcasecmp(opt_string, "same_cpu_crypt"))
1991 set_bit(DM_CRYPT_SAME_CPU, &cc->flags);
1992
1993 else if (!strcasecmp(opt_string, "submit_from_crypt_cpus"))
1994 set_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags);
1995
1996 else {
1997 ti->error = "Invalid feature arguments";
1998 goto bad;
1999 }
2000 }
2001 }
2002
2003 ret = -ENOMEM;
2004 cc->io_queue = alloc_workqueue("kcryptd_io", WQ_MEM_RECLAIM, 1);
2005 if (!cc->io_queue) {
2006 ti->error = "Couldn't create kcryptd io queue";
2007 goto bad;
2008 }
2009
2010 if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
2011 cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1);
2012 else
2013 cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND,
2014 num_online_cpus());
2015 if (!cc->crypt_queue) {
2016 ti->error = "Couldn't create kcryptd queue";
2017 goto bad;
2018 }
2019
2020 init_waitqueue_head(&cc->write_thread_wait);
2021 cc->write_tree = RB_ROOT;
2022
2023 cc->write_thread = kthread_create(dmcrypt_write, cc, "dmcrypt_write");
2024 if (IS_ERR(cc->write_thread)) {
2025 ret = PTR_ERR(cc->write_thread);
2026 cc->write_thread = NULL;
2027 ti->error = "Couldn't spawn write thread";
2028 goto bad;
2029 }
2030 wake_up_process(cc->write_thread);
2031
2032 ti->num_flush_bios = 1;
2033 ti->discard_zeroes_data_unsupported = true;
2034
2035 return 0;
2036
2037bad:
2038 crypt_dtr(ti);
2039 return ret;
2040}
2041
2042static int crypt_map(struct dm_target *ti, struct bio *bio)
2043{
2044 struct dm_crypt_io *io;
2045 struct crypt_config *cc = ti->private;
2046
2047 /*
2048 * If bio is REQ_PREFLUSH or REQ_OP_DISCARD, just bypass crypt queues.
2049 * - for REQ_PREFLUSH device-mapper core ensures that no IO is in-flight
2050 * - for REQ_OP_DISCARD caller must use flush if IO ordering matters
2051 */
2052 if (unlikely(bio->bi_opf & REQ_PREFLUSH ||
2053 bio_op(bio) == REQ_OP_DISCARD)) {
2054 bio->bi_bdev = cc->dev->bdev;
2055 if (bio_sectors(bio))
2056 bio->bi_iter.bi_sector = cc->start +
2057 dm_target_offset(ti, bio->bi_iter.bi_sector);
2058 return DM_MAPIO_REMAPPED;
2059 }
2060
2061 /*
2062 * Check if bio is too large, split as needed.
2063 */
2064 if (unlikely(bio->bi_iter.bi_size > (BIO_MAX_PAGES << PAGE_SHIFT)) &&
2065 bio_data_dir(bio) == WRITE)
2066 dm_accept_partial_bio(bio, ((BIO_MAX_PAGES << PAGE_SHIFT) >> SECTOR_SHIFT));
2067
2068 io = dm_per_bio_data(bio, cc->per_bio_data_size);
2069 crypt_io_init(io, cc, bio, dm_target_offset(ti, bio->bi_iter.bi_sector));
2070 io->ctx.req = (struct skcipher_request *)(io + 1);
2071
2072 if (bio_data_dir(io->base_bio) == READ) {
2073 if (kcryptd_io_read(io, GFP_NOWAIT))
2074 kcryptd_queue_read(io);
2075 } else
2076 kcryptd_queue_crypt(io);
2077
2078 return DM_MAPIO_SUBMITTED;
2079}
2080
2081static void crypt_status(struct dm_target *ti, status_type_t type,
2082 unsigned status_flags, char *result, unsigned maxlen)
2083{
2084 struct crypt_config *cc = ti->private;
2085 unsigned i, sz = 0;
2086 int num_feature_args = 0;
2087
2088 switch (type) {
2089 case STATUSTYPE_INFO:
2090 result[0] = '\0';
2091 break;
2092
2093 case STATUSTYPE_TABLE:
2094 DMEMIT("%s ", cc->cipher_string);
2095
2096 if (cc->key_size > 0) {
2097 if (cc->key_string)
2098 DMEMIT(":%u:%s", cc->key_size, cc->key_string);
2099 else
2100 for (i = 0; i < cc->key_size; i++)
2101 DMEMIT("%02x", cc->key[i]);
2102 } else
2103 DMEMIT("-");
2104
2105 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
2106 cc->dev->name, (unsigned long long)cc->start);
2107
2108 num_feature_args += !!ti->num_discard_bios;
2109 num_feature_args += test_bit(DM_CRYPT_SAME_CPU, &cc->flags);
2110 num_feature_args += test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags);
2111 if (num_feature_args) {
2112 DMEMIT(" %d", num_feature_args);
2113 if (ti->num_discard_bios)
2114 DMEMIT(" allow_discards");
2115 if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
2116 DMEMIT(" same_cpu_crypt");
2117 if (test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags))
2118 DMEMIT(" submit_from_crypt_cpus");
2119 }
2120
2121 break;
2122 }
2123}
2124
2125static void crypt_postsuspend(struct dm_target *ti)
2126{
2127 struct crypt_config *cc = ti->private;
2128
2129 set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
2130}
2131
2132static int crypt_preresume(struct dm_target *ti)
2133{
2134 struct crypt_config *cc = ti->private;
2135
2136 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
2137 DMERR("aborting resume - crypt key is not set.");
2138 return -EAGAIN;
2139 }
2140
2141 return 0;
2142}
2143
2144static void crypt_resume(struct dm_target *ti)
2145{
2146 struct crypt_config *cc = ti->private;
2147
2148 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
2149}
2150
2151/* Message interface
2152 * key set <key>
2153 * key wipe
2154 */
2155static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
2156{
2157 struct crypt_config *cc = ti->private;
2158 int key_size, ret = -EINVAL;
2159
2160 if (argc < 2)
2161 goto error;
2162
2163 if (!strcasecmp(argv[0], "key")) {
2164 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
2165 DMWARN("not suspended during key manipulation.");
2166 return -EINVAL;
2167 }
2168 if (argc == 3 && !strcasecmp(argv[1], "set")) {
2169 /* The key size may not be changed. */
2170 key_size = get_key_size(&argv[2]);
2171 if (key_size < 0 || cc->key_size != key_size) {
2172 memset(argv[2], '0', strlen(argv[2]));
2173 return -EINVAL;
2174 }
2175
2176 ret = crypt_set_key(cc, argv[2]);
2177 if (ret)
2178 return ret;
2179 if (cc->iv_gen_ops && cc->iv_gen_ops->init)
2180 ret = cc->iv_gen_ops->init(cc);
2181 return ret;
2182 }
2183 if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
2184 if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
2185 ret = cc->iv_gen_ops->wipe(cc);
2186 if (ret)
2187 return ret;
2188 }
2189 return crypt_wipe_key(cc);
2190 }
2191 }
2192
2193error:
2194 DMWARN("unrecognised message received.");
2195 return -EINVAL;
2196}
2197
2198static int crypt_iterate_devices(struct dm_target *ti,
2199 iterate_devices_callout_fn fn, void *data)
2200{
2201 struct crypt_config *cc = ti->private;
2202
2203 return fn(ti, cc->dev, cc->start, ti->len, data);
2204}
2205
2206static void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits)
2207{
2208 /*
2209 * Unfortunate constraint that is required to avoid the potential
2210 * for exceeding underlying device's max_segments limits -- due to
2211 * crypt_alloc_buffer() possibly allocating pages for the encryption
2212 * bio that are not as physically contiguous as the original bio.
2213 */
2214 limits->max_segment_size = PAGE_SIZE;
2215}
2216
2217static struct target_type crypt_target = {
2218 .name = "crypt",
2219 .version = {1, 15, 0},
2220 .module = THIS_MODULE,
2221 .ctr = crypt_ctr,
2222 .dtr = crypt_dtr,
2223 .map = crypt_map,
2224 .status = crypt_status,
2225 .postsuspend = crypt_postsuspend,
2226 .preresume = crypt_preresume,
2227 .resume = crypt_resume,
2228 .message = crypt_message,
2229 .iterate_devices = crypt_iterate_devices,
2230 .io_hints = crypt_io_hints,
2231};
2232
2233static int __init dm_crypt_init(void)
2234{
2235 int r;
2236
2237 r = dm_register_target(&crypt_target);
2238 if (r < 0)
2239 DMERR("register failed %d", r);
2240
2241 return r;
2242}
2243
2244static void __exit dm_crypt_exit(void)
2245{
2246 dm_unregister_target(&crypt_target);
2247}
2248
2249module_init(dm_crypt_init);
2250module_exit(dm_crypt_exit);
2251
2252MODULE_AUTHOR("Jana Saout <jana@saout.de>");
2253MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
2254MODULE_LICENSE("GPL");