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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/bio.h>
16#include <linux/blkdev.h>
17#include <linux/mempool.h>
18#include <linux/slab.h>
19#include <linux/crypto.h>
20#include <linux/workqueue.h>
21#include <linux/kthread.h>
22#include <linux/backing-dev.h>
23#include <linux/atomic.h>
24#include <linux/scatterlist.h>
25#include <linux/rbtree.h>
26#include <asm/page.h>
27#include <asm/unaligned.h>
28#include <crypto/hash.h>
29#include <crypto/md5.h>
30#include <crypto/algapi.h>
31#include <crypto/skcipher.h>
32
33#include <linux/device-mapper.h>
34
35#define DM_MSG_PREFIX "crypt"
36
37/*
38 * context holding the current state of a multi-part conversion
39 */
40struct convert_context {
41 struct completion restart;
42 struct bio *bio_in;
43 struct bio *bio_out;
44 struct bvec_iter iter_in;
45 struct bvec_iter iter_out;
46 sector_t cc_sector;
47 atomic_t cc_pending;
48 struct skcipher_request *req;
49};
50
51/*
52 * per bio private data
53 */
54struct dm_crypt_io {
55 struct crypt_config *cc;
56 struct bio *base_bio;
57 struct work_struct work;
58
59 struct convert_context ctx;
60
61 atomic_t io_pending;
62 int error;
63 sector_t sector;
64
65 struct rb_node rb_node;
66} CRYPTO_MINALIGN_ATTR;
67
68struct dm_crypt_request {
69 struct convert_context *ctx;
70 struct scatterlist sg_in;
71 struct scatterlist sg_out;
72 sector_t iv_sector;
73};
74
75struct crypt_config;
76
77struct crypt_iv_operations {
78 int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
79 const char *opts);
80 void (*dtr)(struct crypt_config *cc);
81 int (*init)(struct crypt_config *cc);
82 int (*wipe)(struct crypt_config *cc);
83 int (*generator)(struct crypt_config *cc, u8 *iv,
84 struct dm_crypt_request *dmreq);
85 int (*post)(struct crypt_config *cc, u8 *iv,
86 struct dm_crypt_request *dmreq);
87};
88
89struct iv_essiv_private {
90 struct crypto_ahash *hash_tfm;
91 u8 *salt;
92};
93
94struct iv_benbi_private {
95 int shift;
96};
97
98#define LMK_SEED_SIZE 64 /* hash + 0 */
99struct iv_lmk_private {
100 struct crypto_shash *hash_tfm;
101 u8 *seed;
102};
103
104#define TCW_WHITENING_SIZE 16
105struct iv_tcw_private {
106 struct crypto_shash *crc32_tfm;
107 u8 *iv_seed;
108 u8 *whitening;
109};
110
111/*
112 * Crypt: maps a linear range of a block device
113 * and encrypts / decrypts at the same time.
114 */
115enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID,
116 DM_CRYPT_SAME_CPU, DM_CRYPT_NO_OFFLOAD,
117 DM_CRYPT_EXIT_THREAD};
118
119/*
120 * The fields in here must be read only after initialization.
121 */
122struct crypt_config {
123 struct dm_dev *dev;
124 sector_t start;
125
126 /*
127 * pool for per bio private data, crypto requests and
128 * encryption requeusts/buffer pages
129 */
130 mempool_t *req_pool;
131 mempool_t *page_pool;
132 struct bio_set *bs;
133 struct mutex bio_alloc_lock;
134
135 struct workqueue_struct *io_queue;
136 struct workqueue_struct *crypt_queue;
137
138 struct task_struct *write_thread;
139 wait_queue_head_t write_thread_wait;
140 struct rb_root write_tree;
141
142 char *cipher;
143 char *cipher_string;
144
145 struct crypt_iv_operations *iv_gen_ops;
146 union {
147 struct iv_essiv_private essiv;
148 struct iv_benbi_private benbi;
149 struct iv_lmk_private lmk;
150 struct iv_tcw_private tcw;
151 } iv_gen_private;
152 sector_t iv_offset;
153 unsigned int iv_size;
154
155 /* ESSIV: struct crypto_cipher *essiv_tfm */
156 void *iv_private;
157 struct crypto_skcipher **tfms;
158 unsigned tfms_count;
159
160 /*
161 * Layout of each crypto request:
162 *
163 * struct skcipher_request
164 * context
165 * padding
166 * struct dm_crypt_request
167 * padding
168 * IV
169 *
170 * The padding is added so that dm_crypt_request and the IV are
171 * correctly aligned.
172 */
173 unsigned int dmreq_start;
174
175 unsigned int per_bio_data_size;
176
177 unsigned long flags;
178 unsigned int key_size;
179 unsigned int key_parts; /* independent parts in key buffer */
180 unsigned int key_extra_size; /* additional keys length */
181 u8 key[0];
182};
183
184#define MIN_IOS 16
185
186static void clone_init(struct dm_crypt_io *, struct bio *);
187static void kcryptd_queue_crypt(struct dm_crypt_io *io);
188static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq);
189
190/*
191 * Use this to access cipher attributes that are the same for each CPU.
192 */
193static struct crypto_skcipher *any_tfm(struct crypt_config *cc)
194{
195 return cc->tfms[0];
196}
197
198/*
199 * Different IV generation algorithms:
200 *
201 * plain: the initial vector is the 32-bit little-endian version of the sector
202 * number, padded with zeros if necessary.
203 *
204 * plain64: the initial vector is the 64-bit little-endian version of the sector
205 * number, padded with zeros if necessary.
206 *
207 * essiv: "encrypted sector|salt initial vector", the sector number is
208 * encrypted with the bulk cipher using a salt as key. The salt
209 * should be derived from the bulk cipher's key via hashing.
210 *
211 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
212 * (needed for LRW-32-AES and possible other narrow block modes)
213 *
214 * null: the initial vector is always zero. Provides compatibility with
215 * obsolete loop_fish2 devices. Do not use for new devices.
216 *
217 * lmk: Compatible implementation of the block chaining mode used
218 * by the Loop-AES block device encryption system
219 * designed by Jari Ruusu. See http://loop-aes.sourceforge.net/
220 * It operates on full 512 byte sectors and uses CBC
221 * with an IV derived from the sector number, the data and
222 * optionally extra IV seed.
223 * This means that after decryption the first block
224 * of sector must be tweaked according to decrypted data.
225 * Loop-AES can use three encryption schemes:
226 * version 1: is plain aes-cbc mode
227 * version 2: uses 64 multikey scheme with lmk IV generator
228 * version 3: the same as version 2 with additional IV seed
229 * (it uses 65 keys, last key is used as IV seed)
230 *
231 * tcw: Compatible implementation of the block chaining mode used
232 * by the TrueCrypt device encryption system (prior to version 4.1).
233 * For more info see: https://gitlab.com/cryptsetup/cryptsetup/wikis/TrueCryptOnDiskFormat
234 * It operates on full 512 byte sectors and uses CBC
235 * with an IV derived from initial key and the sector number.
236 * In addition, whitening value is applied on every sector, whitening
237 * is calculated from initial key, sector number and mixed using CRC32.
238 * Note that this encryption scheme is vulnerable to watermarking attacks
239 * and should be used for old compatible containers access only.
240 *
241 * plumb: unimplemented, see:
242 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
243 */
244
245static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv,
246 struct dm_crypt_request *dmreq)
247{
248 memset(iv, 0, cc->iv_size);
249 *(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff);
250
251 return 0;
252}
253
254static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
255 struct dm_crypt_request *dmreq)
256{
257 memset(iv, 0, cc->iv_size);
258 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
259
260 return 0;
261}
262
263/* Initialise ESSIV - compute salt but no local memory allocations */
264static int crypt_iv_essiv_init(struct crypt_config *cc)
265{
266 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
267 AHASH_REQUEST_ON_STACK(req, essiv->hash_tfm);
268 struct scatterlist sg;
269 struct crypto_cipher *essiv_tfm;
270 int err;
271
272 sg_init_one(&sg, cc->key, cc->key_size);
273 ahash_request_set_tfm(req, essiv->hash_tfm);
274 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
275 ahash_request_set_crypt(req, &sg, essiv->salt, cc->key_size);
276
277 err = crypto_ahash_digest(req);
278 ahash_request_zero(req);
279 if (err)
280 return err;
281
282 essiv_tfm = cc->iv_private;
283
284 err = crypto_cipher_setkey(essiv_tfm, essiv->salt,
285 crypto_ahash_digestsize(essiv->hash_tfm));
286 if (err)
287 return err;
288
289 return 0;
290}
291
292/* Wipe salt and reset key derived from volume key */
293static int crypt_iv_essiv_wipe(struct crypt_config *cc)
294{
295 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
296 unsigned salt_size = crypto_ahash_digestsize(essiv->hash_tfm);
297 struct crypto_cipher *essiv_tfm;
298 int r, err = 0;
299
300 memset(essiv->salt, 0, salt_size);
301
302 essiv_tfm = cc->iv_private;
303 r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size);
304 if (r)
305 err = r;
306
307 return err;
308}
309
310/* Set up per cpu cipher state */
311static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc,
312 struct dm_target *ti,
313 u8 *salt, unsigned saltsize)
314{
315 struct crypto_cipher *essiv_tfm;
316 int err;
317
318 /* Setup the essiv_tfm with the given salt */
319 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
320 if (IS_ERR(essiv_tfm)) {
321 ti->error = "Error allocating crypto tfm for ESSIV";
322 return essiv_tfm;
323 }
324
325 if (crypto_cipher_blocksize(essiv_tfm) !=
326 crypto_skcipher_ivsize(any_tfm(cc))) {
327 ti->error = "Block size of ESSIV cipher does "
328 "not match IV size of block cipher";
329 crypto_free_cipher(essiv_tfm);
330 return ERR_PTR(-EINVAL);
331 }
332
333 err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
334 if (err) {
335 ti->error = "Failed to set key for ESSIV cipher";
336 crypto_free_cipher(essiv_tfm);
337 return ERR_PTR(err);
338 }
339
340 return essiv_tfm;
341}
342
343static void crypt_iv_essiv_dtr(struct crypt_config *cc)
344{
345 struct crypto_cipher *essiv_tfm;
346 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
347
348 crypto_free_ahash(essiv->hash_tfm);
349 essiv->hash_tfm = NULL;
350
351 kzfree(essiv->salt);
352 essiv->salt = NULL;
353
354 essiv_tfm = cc->iv_private;
355
356 if (essiv_tfm)
357 crypto_free_cipher(essiv_tfm);
358
359 cc->iv_private = NULL;
360}
361
362static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
363 const char *opts)
364{
365 struct crypto_cipher *essiv_tfm = NULL;
366 struct crypto_ahash *hash_tfm = NULL;
367 u8 *salt = NULL;
368 int err;
369
370 if (!opts) {
371 ti->error = "Digest algorithm missing for ESSIV mode";
372 return -EINVAL;
373 }
374
375 /* Allocate hash algorithm */
376 hash_tfm = crypto_alloc_ahash(opts, 0, CRYPTO_ALG_ASYNC);
377 if (IS_ERR(hash_tfm)) {
378 ti->error = "Error initializing ESSIV hash";
379 err = PTR_ERR(hash_tfm);
380 goto bad;
381 }
382
383 salt = kzalloc(crypto_ahash_digestsize(hash_tfm), GFP_KERNEL);
384 if (!salt) {
385 ti->error = "Error kmallocing salt storage in ESSIV";
386 err = -ENOMEM;
387 goto bad;
388 }
389
390 cc->iv_gen_private.essiv.salt = salt;
391 cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
392
393 essiv_tfm = setup_essiv_cpu(cc, ti, salt,
394 crypto_ahash_digestsize(hash_tfm));
395 if (IS_ERR(essiv_tfm)) {
396 crypt_iv_essiv_dtr(cc);
397 return PTR_ERR(essiv_tfm);
398 }
399 cc->iv_private = essiv_tfm;
400
401 return 0;
402
403bad:
404 if (hash_tfm && !IS_ERR(hash_tfm))
405 crypto_free_ahash(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 = 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_skcipher_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 SHASH_DESC_ON_STACK(desc, lmk->hash_tfm);
539 struct md5_state md5state;
540 __le32 buf[4];
541 int i, r;
542
543 desc->tfm = lmk->hash_tfm;
544 desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
545
546 r = crypto_shash_init(desc);
547 if (r)
548 return r;
549
550 if (lmk->seed) {
551 r = crypto_shash_update(desc, lmk->seed, LMK_SEED_SIZE);
552 if (r)
553 return r;
554 }
555
556 /* Sector is always 512B, block size 16, add data of blocks 1-31 */
557 r = crypto_shash_update(desc, data + 16, 16 * 31);
558 if (r)
559 return r;
560
561 /* Sector is cropped to 56 bits here */
562 buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF);
563 buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000);
564 buf[2] = cpu_to_le32(4024);
565 buf[3] = 0;
566 r = crypto_shash_update(desc, (u8 *)buf, sizeof(buf));
567 if (r)
568 return r;
569
570 /* No MD5 padding here */
571 r = crypto_shash_export(desc, &md5state);
572 if (r)
573 return r;
574
575 for (i = 0; i < MD5_HASH_WORDS; i++)
576 __cpu_to_le32s(&md5state.hash[i]);
577 memcpy(iv, &md5state.hash, cc->iv_size);
578
579 return 0;
580}
581
582static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv,
583 struct dm_crypt_request *dmreq)
584{
585 u8 *src;
586 int r = 0;
587
588 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) {
589 src = kmap_atomic(sg_page(&dmreq->sg_in));
590 r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset);
591 kunmap_atomic(src);
592 } else
593 memset(iv, 0, cc->iv_size);
594
595 return r;
596}
597
598static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv,
599 struct dm_crypt_request *dmreq)
600{
601 u8 *dst;
602 int r;
603
604 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE)
605 return 0;
606
607 dst = kmap_atomic(sg_page(&dmreq->sg_out));
608 r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset);
609
610 /* Tweak the first block of plaintext sector */
611 if (!r)
612 crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size);
613
614 kunmap_atomic(dst);
615 return r;
616}
617
618static void crypt_iv_tcw_dtr(struct crypt_config *cc)
619{
620 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
621
622 kzfree(tcw->iv_seed);
623 tcw->iv_seed = NULL;
624 kzfree(tcw->whitening);
625 tcw->whitening = NULL;
626
627 if (tcw->crc32_tfm && !IS_ERR(tcw->crc32_tfm))
628 crypto_free_shash(tcw->crc32_tfm);
629 tcw->crc32_tfm = NULL;
630}
631
632static int crypt_iv_tcw_ctr(struct crypt_config *cc, struct dm_target *ti,
633 const char *opts)
634{
635 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
636
637 if (cc->key_size <= (cc->iv_size + TCW_WHITENING_SIZE)) {
638 ti->error = "Wrong key size for TCW";
639 return -EINVAL;
640 }
641
642 tcw->crc32_tfm = crypto_alloc_shash("crc32", 0, 0);
643 if (IS_ERR(tcw->crc32_tfm)) {
644 ti->error = "Error initializing CRC32 in TCW";
645 return PTR_ERR(tcw->crc32_tfm);
646 }
647
648 tcw->iv_seed = kzalloc(cc->iv_size, GFP_KERNEL);
649 tcw->whitening = kzalloc(TCW_WHITENING_SIZE, GFP_KERNEL);
650 if (!tcw->iv_seed || !tcw->whitening) {
651 crypt_iv_tcw_dtr(cc);
652 ti->error = "Error allocating seed storage in TCW";
653 return -ENOMEM;
654 }
655
656 return 0;
657}
658
659static int crypt_iv_tcw_init(struct crypt_config *cc)
660{
661 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
662 int key_offset = cc->key_size - cc->iv_size - TCW_WHITENING_SIZE;
663
664 memcpy(tcw->iv_seed, &cc->key[key_offset], cc->iv_size);
665 memcpy(tcw->whitening, &cc->key[key_offset + cc->iv_size],
666 TCW_WHITENING_SIZE);
667
668 return 0;
669}
670
671static int crypt_iv_tcw_wipe(struct crypt_config *cc)
672{
673 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
674
675 memset(tcw->iv_seed, 0, cc->iv_size);
676 memset(tcw->whitening, 0, TCW_WHITENING_SIZE);
677
678 return 0;
679}
680
681static int crypt_iv_tcw_whitening(struct crypt_config *cc,
682 struct dm_crypt_request *dmreq,
683 u8 *data)
684{
685 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
686 u64 sector = cpu_to_le64((u64)dmreq->iv_sector);
687 u8 buf[TCW_WHITENING_SIZE];
688 SHASH_DESC_ON_STACK(desc, tcw->crc32_tfm);
689 int i, r;
690
691 /* xor whitening with sector number */
692 memcpy(buf, tcw->whitening, TCW_WHITENING_SIZE);
693 crypto_xor(buf, (u8 *)§or, 8);
694 crypto_xor(&buf[8], (u8 *)§or, 8);
695
696 /* calculate crc32 for every 32bit part and xor it */
697 desc->tfm = tcw->crc32_tfm;
698 desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
699 for (i = 0; i < 4; i++) {
700 r = crypto_shash_init(desc);
701 if (r)
702 goto out;
703 r = crypto_shash_update(desc, &buf[i * 4], 4);
704 if (r)
705 goto out;
706 r = crypto_shash_final(desc, &buf[i * 4]);
707 if (r)
708 goto out;
709 }
710 crypto_xor(&buf[0], &buf[12], 4);
711 crypto_xor(&buf[4], &buf[8], 4);
712
713 /* apply whitening (8 bytes) to whole sector */
714 for (i = 0; i < ((1 << SECTOR_SHIFT) / 8); i++)
715 crypto_xor(data + i * 8, buf, 8);
716out:
717 memzero_explicit(buf, sizeof(buf));
718 return r;
719}
720
721static int crypt_iv_tcw_gen(struct crypt_config *cc, u8 *iv,
722 struct dm_crypt_request *dmreq)
723{
724 struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
725 u64 sector = cpu_to_le64((u64)dmreq->iv_sector);
726 u8 *src;
727 int r = 0;
728
729 /* Remove whitening from ciphertext */
730 if (bio_data_dir(dmreq->ctx->bio_in) != WRITE) {
731 src = kmap_atomic(sg_page(&dmreq->sg_in));
732 r = crypt_iv_tcw_whitening(cc, dmreq, src + dmreq->sg_in.offset);
733 kunmap_atomic(src);
734 }
735
736 /* Calculate IV */
737 memcpy(iv, tcw->iv_seed, cc->iv_size);
738 crypto_xor(iv, (u8 *)§or, 8);
739 if (cc->iv_size > 8)
740 crypto_xor(&iv[8], (u8 *)§or, cc->iv_size - 8);
741
742 return r;
743}
744
745static int crypt_iv_tcw_post(struct crypt_config *cc, u8 *iv,
746 struct dm_crypt_request *dmreq)
747{
748 u8 *dst;
749 int r;
750
751 if (bio_data_dir(dmreq->ctx->bio_in) != WRITE)
752 return 0;
753
754 /* Apply whitening on ciphertext */
755 dst = kmap_atomic(sg_page(&dmreq->sg_out));
756 r = crypt_iv_tcw_whitening(cc, dmreq, dst + dmreq->sg_out.offset);
757 kunmap_atomic(dst);
758
759 return r;
760}
761
762static struct crypt_iv_operations crypt_iv_plain_ops = {
763 .generator = crypt_iv_plain_gen
764};
765
766static struct crypt_iv_operations crypt_iv_plain64_ops = {
767 .generator = crypt_iv_plain64_gen
768};
769
770static struct crypt_iv_operations crypt_iv_essiv_ops = {
771 .ctr = crypt_iv_essiv_ctr,
772 .dtr = crypt_iv_essiv_dtr,
773 .init = crypt_iv_essiv_init,
774 .wipe = crypt_iv_essiv_wipe,
775 .generator = crypt_iv_essiv_gen
776};
777
778static struct crypt_iv_operations crypt_iv_benbi_ops = {
779 .ctr = crypt_iv_benbi_ctr,
780 .dtr = crypt_iv_benbi_dtr,
781 .generator = crypt_iv_benbi_gen
782};
783
784static struct crypt_iv_operations crypt_iv_null_ops = {
785 .generator = crypt_iv_null_gen
786};
787
788static struct crypt_iv_operations crypt_iv_lmk_ops = {
789 .ctr = crypt_iv_lmk_ctr,
790 .dtr = crypt_iv_lmk_dtr,
791 .init = crypt_iv_lmk_init,
792 .wipe = crypt_iv_lmk_wipe,
793 .generator = crypt_iv_lmk_gen,
794 .post = crypt_iv_lmk_post
795};
796
797static struct crypt_iv_operations crypt_iv_tcw_ops = {
798 .ctr = crypt_iv_tcw_ctr,
799 .dtr = crypt_iv_tcw_dtr,
800 .init = crypt_iv_tcw_init,
801 .wipe = crypt_iv_tcw_wipe,
802 .generator = crypt_iv_tcw_gen,
803 .post = crypt_iv_tcw_post
804};
805
806static void crypt_convert_init(struct crypt_config *cc,
807 struct convert_context *ctx,
808 struct bio *bio_out, struct bio *bio_in,
809 sector_t sector)
810{
811 ctx->bio_in = bio_in;
812 ctx->bio_out = bio_out;
813 if (bio_in)
814 ctx->iter_in = bio_in->bi_iter;
815 if (bio_out)
816 ctx->iter_out = bio_out->bi_iter;
817 ctx->cc_sector = sector + cc->iv_offset;
818 init_completion(&ctx->restart);
819}
820
821static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
822 struct skcipher_request *req)
823{
824 return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
825}
826
827static struct skcipher_request *req_of_dmreq(struct crypt_config *cc,
828 struct dm_crypt_request *dmreq)
829{
830 return (struct skcipher_request *)((char *)dmreq - cc->dmreq_start);
831}
832
833static u8 *iv_of_dmreq(struct crypt_config *cc,
834 struct dm_crypt_request *dmreq)
835{
836 return (u8 *)ALIGN((unsigned long)(dmreq + 1),
837 crypto_skcipher_alignmask(any_tfm(cc)) + 1);
838}
839
840static int crypt_convert_block(struct crypt_config *cc,
841 struct convert_context *ctx,
842 struct skcipher_request *req)
843{
844 struct bio_vec bv_in = bio_iter_iovec(ctx->bio_in, ctx->iter_in);
845 struct bio_vec bv_out = bio_iter_iovec(ctx->bio_out, ctx->iter_out);
846 struct dm_crypt_request *dmreq;
847 u8 *iv;
848 int r;
849
850 dmreq = dmreq_of_req(cc, req);
851 iv = iv_of_dmreq(cc, dmreq);
852
853 dmreq->iv_sector = ctx->cc_sector;
854 dmreq->ctx = ctx;
855 sg_init_table(&dmreq->sg_in, 1);
856 sg_set_page(&dmreq->sg_in, bv_in.bv_page, 1 << SECTOR_SHIFT,
857 bv_in.bv_offset);
858
859 sg_init_table(&dmreq->sg_out, 1);
860 sg_set_page(&dmreq->sg_out, bv_out.bv_page, 1 << SECTOR_SHIFT,
861 bv_out.bv_offset);
862
863 bio_advance_iter(ctx->bio_in, &ctx->iter_in, 1 << SECTOR_SHIFT);
864 bio_advance_iter(ctx->bio_out, &ctx->iter_out, 1 << SECTOR_SHIFT);
865
866 if (cc->iv_gen_ops) {
867 r = cc->iv_gen_ops->generator(cc, iv, dmreq);
868 if (r < 0)
869 return r;
870 }
871
872 skcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
873 1 << SECTOR_SHIFT, iv);
874
875 if (bio_data_dir(ctx->bio_in) == WRITE)
876 r = crypto_skcipher_encrypt(req);
877 else
878 r = crypto_skcipher_decrypt(req);
879
880 if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
881 r = cc->iv_gen_ops->post(cc, iv, dmreq);
882
883 return r;
884}
885
886static void kcryptd_async_done(struct crypto_async_request *async_req,
887 int error);
888
889static void crypt_alloc_req(struct crypt_config *cc,
890 struct convert_context *ctx)
891{
892 unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1);
893
894 if (!ctx->req)
895 ctx->req = mempool_alloc(cc->req_pool, GFP_NOIO);
896
897 skcipher_request_set_tfm(ctx->req, cc->tfms[key_index]);
898
899 /*
900 * Use REQ_MAY_BACKLOG so a cipher driver internally backlogs
901 * requests if driver request queue is full.
902 */
903 skcipher_request_set_callback(ctx->req,
904 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
905 kcryptd_async_done, dmreq_of_req(cc, ctx->req));
906}
907
908static void crypt_free_req(struct crypt_config *cc,
909 struct skcipher_request *req, struct bio *base_bio)
910{
911 struct dm_crypt_io *io = dm_per_bio_data(base_bio, cc->per_bio_data_size);
912
913 if ((struct skcipher_request *)(io + 1) != req)
914 mempool_free(req, cc->req_pool);
915}
916
917/*
918 * Encrypt / decrypt data from one bio to another one (can be the same one)
919 */
920static int crypt_convert(struct crypt_config *cc,
921 struct convert_context *ctx)
922{
923 int r;
924
925 atomic_set(&ctx->cc_pending, 1);
926
927 while (ctx->iter_in.bi_size && ctx->iter_out.bi_size) {
928
929 crypt_alloc_req(cc, ctx);
930
931 atomic_inc(&ctx->cc_pending);
932
933 r = crypt_convert_block(cc, ctx, ctx->req);
934
935 switch (r) {
936 /*
937 * The request was queued by a crypto driver
938 * but the driver request queue is full, let's wait.
939 */
940 case -EBUSY:
941 wait_for_completion(&ctx->restart);
942 reinit_completion(&ctx->restart);
943 /* fall through */
944 /*
945 * The request is queued and processed asynchronously,
946 * completion function kcryptd_async_done() will be called.
947 */
948 case -EINPROGRESS:
949 ctx->req = NULL;
950 ctx->cc_sector++;
951 continue;
952 /*
953 * The request was already processed (synchronously).
954 */
955 case 0:
956 atomic_dec(&ctx->cc_pending);
957 ctx->cc_sector++;
958 cond_resched();
959 continue;
960
961 /* There was an error while processing the request. */
962 default:
963 atomic_dec(&ctx->cc_pending);
964 return r;
965 }
966 }
967
968 return 0;
969}
970
971static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone);
972
973/*
974 * Generate a new unfragmented bio with the given size
975 * This should never violate the device limitations (but only because
976 * max_segment_size is being constrained to PAGE_SIZE).
977 *
978 * This function may be called concurrently. If we allocate from the mempool
979 * concurrently, there is a possibility of deadlock. For example, if we have
980 * mempool of 256 pages, two processes, each wanting 256, pages allocate from
981 * the mempool concurrently, it may deadlock in a situation where both processes
982 * have allocated 128 pages and the mempool is exhausted.
983 *
984 * In order to avoid this scenario we allocate the pages under a mutex.
985 *
986 * In order to not degrade performance with excessive locking, we try
987 * non-blocking allocations without a mutex first but on failure we fallback
988 * to blocking allocations with a mutex.
989 */
990static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
991{
992 struct crypt_config *cc = io->cc;
993 struct bio *clone;
994 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
995 gfp_t gfp_mask = GFP_NOWAIT | __GFP_HIGHMEM;
996 unsigned i, len, remaining_size;
997 struct page *page;
998 struct bio_vec *bvec;
999
1000retry:
1001 if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM))
1002 mutex_lock(&cc->bio_alloc_lock);
1003
1004 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
1005 if (!clone)
1006 goto return_clone;
1007
1008 clone_init(io, clone);
1009
1010 remaining_size = size;
1011
1012 for (i = 0; i < nr_iovecs; i++) {
1013 page = mempool_alloc(cc->page_pool, gfp_mask);
1014 if (!page) {
1015 crypt_free_buffer_pages(cc, clone);
1016 bio_put(clone);
1017 gfp_mask |= __GFP_DIRECT_RECLAIM;
1018 goto retry;
1019 }
1020
1021 len = (remaining_size > PAGE_SIZE) ? PAGE_SIZE : remaining_size;
1022
1023 bvec = &clone->bi_io_vec[clone->bi_vcnt++];
1024 bvec->bv_page = page;
1025 bvec->bv_len = len;
1026 bvec->bv_offset = 0;
1027
1028 clone->bi_iter.bi_size += len;
1029
1030 remaining_size -= len;
1031 }
1032
1033return_clone:
1034 if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM))
1035 mutex_unlock(&cc->bio_alloc_lock);
1036
1037 return clone;
1038}
1039
1040static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
1041{
1042 unsigned int i;
1043 struct bio_vec *bv;
1044
1045 bio_for_each_segment_all(bv, clone, i) {
1046 BUG_ON(!bv->bv_page);
1047 mempool_free(bv->bv_page, cc->page_pool);
1048 bv->bv_page = NULL;
1049 }
1050}
1051
1052static void crypt_io_init(struct dm_crypt_io *io, struct crypt_config *cc,
1053 struct bio *bio, sector_t sector)
1054{
1055 io->cc = cc;
1056 io->base_bio = bio;
1057 io->sector = sector;
1058 io->error = 0;
1059 io->ctx.req = NULL;
1060 atomic_set(&io->io_pending, 0);
1061}
1062
1063static void crypt_inc_pending(struct dm_crypt_io *io)
1064{
1065 atomic_inc(&io->io_pending);
1066}
1067
1068/*
1069 * One of the bios was finished. Check for completion of
1070 * the whole request and correctly clean up the buffer.
1071 */
1072static void crypt_dec_pending(struct dm_crypt_io *io)
1073{
1074 struct crypt_config *cc = io->cc;
1075 struct bio *base_bio = io->base_bio;
1076 int error = io->error;
1077
1078 if (!atomic_dec_and_test(&io->io_pending))
1079 return;
1080
1081 if (io->ctx.req)
1082 crypt_free_req(cc, io->ctx.req, base_bio);
1083
1084 base_bio->bi_error = error;
1085 bio_endio(base_bio);
1086}
1087
1088/*
1089 * kcryptd/kcryptd_io:
1090 *
1091 * Needed because it would be very unwise to do decryption in an
1092 * interrupt context.
1093 *
1094 * kcryptd performs the actual encryption or decryption.
1095 *
1096 * kcryptd_io performs the IO submission.
1097 *
1098 * They must be separated as otherwise the final stages could be
1099 * starved by new requests which can block in the first stages due
1100 * to memory allocation.
1101 *
1102 * The work is done per CPU global for all dm-crypt instances.
1103 * They should not depend on each other and do not block.
1104 */
1105static void crypt_endio(struct bio *clone)
1106{
1107 struct dm_crypt_io *io = clone->bi_private;
1108 struct crypt_config *cc = io->cc;
1109 unsigned rw = bio_data_dir(clone);
1110 int error;
1111
1112 /*
1113 * free the processed pages
1114 */
1115 if (rw == WRITE)
1116 crypt_free_buffer_pages(cc, clone);
1117
1118 error = clone->bi_error;
1119 bio_put(clone);
1120
1121 if (rw == READ && !error) {
1122 kcryptd_queue_crypt(io);
1123 return;
1124 }
1125
1126 if (unlikely(error))
1127 io->error = error;
1128
1129 crypt_dec_pending(io);
1130}
1131
1132static void clone_init(struct dm_crypt_io *io, struct bio *clone)
1133{
1134 struct crypt_config *cc = io->cc;
1135
1136 clone->bi_private = io;
1137 clone->bi_end_io = crypt_endio;
1138 clone->bi_bdev = cc->dev->bdev;
1139 clone->bi_rw = io->base_bio->bi_rw;
1140}
1141
1142static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
1143{
1144 struct crypt_config *cc = io->cc;
1145 struct bio *clone;
1146
1147 /*
1148 * We need the original biovec array in order to decrypt
1149 * the whole bio data *afterwards* -- thanks to immutable
1150 * biovecs we don't need to worry about the block layer
1151 * modifying the biovec array; so leverage bio_clone_fast().
1152 */
1153 clone = bio_clone_fast(io->base_bio, gfp, cc->bs);
1154 if (!clone)
1155 return 1;
1156
1157 crypt_inc_pending(io);
1158
1159 clone_init(io, clone);
1160 clone->bi_iter.bi_sector = cc->start + io->sector;
1161
1162 generic_make_request(clone);
1163 return 0;
1164}
1165
1166static void kcryptd_io_read_work(struct work_struct *work)
1167{
1168 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1169
1170 crypt_inc_pending(io);
1171 if (kcryptd_io_read(io, GFP_NOIO))
1172 io->error = -ENOMEM;
1173 crypt_dec_pending(io);
1174}
1175
1176static void kcryptd_queue_read(struct dm_crypt_io *io)
1177{
1178 struct crypt_config *cc = io->cc;
1179
1180 INIT_WORK(&io->work, kcryptd_io_read_work);
1181 queue_work(cc->io_queue, &io->work);
1182}
1183
1184static void kcryptd_io_write(struct dm_crypt_io *io)
1185{
1186 struct bio *clone = io->ctx.bio_out;
1187
1188 generic_make_request(clone);
1189}
1190
1191#define crypt_io_from_node(node) rb_entry((node), struct dm_crypt_io, rb_node)
1192
1193static int dmcrypt_write(void *data)
1194{
1195 struct crypt_config *cc = data;
1196 struct dm_crypt_io *io;
1197
1198 while (1) {
1199 struct rb_root write_tree;
1200 struct blk_plug plug;
1201
1202 DECLARE_WAITQUEUE(wait, current);
1203
1204 spin_lock_irq(&cc->write_thread_wait.lock);
1205continue_locked:
1206
1207 if (!RB_EMPTY_ROOT(&cc->write_tree))
1208 goto pop_from_list;
1209
1210 if (unlikely(test_bit(DM_CRYPT_EXIT_THREAD, &cc->flags))) {
1211 spin_unlock_irq(&cc->write_thread_wait.lock);
1212 break;
1213 }
1214
1215 __set_current_state(TASK_INTERRUPTIBLE);
1216 __add_wait_queue(&cc->write_thread_wait, &wait);
1217
1218 spin_unlock_irq(&cc->write_thread_wait.lock);
1219
1220 schedule();
1221
1222 spin_lock_irq(&cc->write_thread_wait.lock);
1223 __remove_wait_queue(&cc->write_thread_wait, &wait);
1224 goto continue_locked;
1225
1226pop_from_list:
1227 write_tree = cc->write_tree;
1228 cc->write_tree = RB_ROOT;
1229 spin_unlock_irq(&cc->write_thread_wait.lock);
1230
1231 BUG_ON(rb_parent(write_tree.rb_node));
1232
1233 /*
1234 * Note: we cannot walk the tree here with rb_next because
1235 * the structures may be freed when kcryptd_io_write is called.
1236 */
1237 blk_start_plug(&plug);
1238 do {
1239 io = crypt_io_from_node(rb_first(&write_tree));
1240 rb_erase(&io->rb_node, &write_tree);
1241 kcryptd_io_write(io);
1242 } while (!RB_EMPTY_ROOT(&write_tree));
1243 blk_finish_plug(&plug);
1244 }
1245 return 0;
1246}
1247
1248static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
1249{
1250 struct bio *clone = io->ctx.bio_out;
1251 struct crypt_config *cc = io->cc;
1252 unsigned long flags;
1253 sector_t sector;
1254 struct rb_node **rbp, *parent;
1255
1256 if (unlikely(io->error < 0)) {
1257 crypt_free_buffer_pages(cc, clone);
1258 bio_put(clone);
1259 crypt_dec_pending(io);
1260 return;
1261 }
1262
1263 /* crypt_convert should have filled the clone bio */
1264 BUG_ON(io->ctx.iter_out.bi_size);
1265
1266 clone->bi_iter.bi_sector = cc->start + io->sector;
1267
1268 if (likely(!async) && test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) {
1269 generic_make_request(clone);
1270 return;
1271 }
1272
1273 spin_lock_irqsave(&cc->write_thread_wait.lock, flags);
1274 rbp = &cc->write_tree.rb_node;
1275 parent = NULL;
1276 sector = io->sector;
1277 while (*rbp) {
1278 parent = *rbp;
1279 if (sector < crypt_io_from_node(parent)->sector)
1280 rbp = &(*rbp)->rb_left;
1281 else
1282 rbp = &(*rbp)->rb_right;
1283 }
1284 rb_link_node(&io->rb_node, parent, rbp);
1285 rb_insert_color(&io->rb_node, &cc->write_tree);
1286
1287 wake_up_locked(&cc->write_thread_wait);
1288 spin_unlock_irqrestore(&cc->write_thread_wait.lock, flags);
1289}
1290
1291static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
1292{
1293 struct crypt_config *cc = io->cc;
1294 struct bio *clone;
1295 int crypt_finished;
1296 sector_t sector = io->sector;
1297 int r;
1298
1299 /*
1300 * Prevent io from disappearing until this function completes.
1301 */
1302 crypt_inc_pending(io);
1303 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
1304
1305 clone = crypt_alloc_buffer(io, io->base_bio->bi_iter.bi_size);
1306 if (unlikely(!clone)) {
1307 io->error = -EIO;
1308 goto dec;
1309 }
1310
1311 io->ctx.bio_out = clone;
1312 io->ctx.iter_out = clone->bi_iter;
1313
1314 sector += bio_sectors(clone);
1315
1316 crypt_inc_pending(io);
1317 r = crypt_convert(cc, &io->ctx);
1318 if (r)
1319 io->error = -EIO;
1320 crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending);
1321
1322 /* Encryption was already finished, submit io now */
1323 if (crypt_finished) {
1324 kcryptd_crypt_write_io_submit(io, 0);
1325 io->sector = sector;
1326 }
1327
1328dec:
1329 crypt_dec_pending(io);
1330}
1331
1332static void kcryptd_crypt_read_done(struct dm_crypt_io *io)
1333{
1334 crypt_dec_pending(io);
1335}
1336
1337static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
1338{
1339 struct crypt_config *cc = io->cc;
1340 int r = 0;
1341
1342 crypt_inc_pending(io);
1343
1344 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
1345 io->sector);
1346
1347 r = crypt_convert(cc, &io->ctx);
1348 if (r < 0)
1349 io->error = -EIO;
1350
1351 if (atomic_dec_and_test(&io->ctx.cc_pending))
1352 kcryptd_crypt_read_done(io);
1353
1354 crypt_dec_pending(io);
1355}
1356
1357static void kcryptd_async_done(struct crypto_async_request *async_req,
1358 int error)
1359{
1360 struct dm_crypt_request *dmreq = async_req->data;
1361 struct convert_context *ctx = dmreq->ctx;
1362 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
1363 struct crypt_config *cc = io->cc;
1364
1365 /*
1366 * A request from crypto driver backlog is going to be processed now,
1367 * finish the completion and continue in crypt_convert().
1368 * (Callback will be called for the second time for this request.)
1369 */
1370 if (error == -EINPROGRESS) {
1371 complete(&ctx->restart);
1372 return;
1373 }
1374
1375 if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
1376 error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
1377
1378 if (error < 0)
1379 io->error = -EIO;
1380
1381 crypt_free_req(cc, req_of_dmreq(cc, dmreq), io->base_bio);
1382
1383 if (!atomic_dec_and_test(&ctx->cc_pending))
1384 return;
1385
1386 if (bio_data_dir(io->base_bio) == READ)
1387 kcryptd_crypt_read_done(io);
1388 else
1389 kcryptd_crypt_write_io_submit(io, 1);
1390}
1391
1392static void kcryptd_crypt(struct work_struct *work)
1393{
1394 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1395
1396 if (bio_data_dir(io->base_bio) == READ)
1397 kcryptd_crypt_read_convert(io);
1398 else
1399 kcryptd_crypt_write_convert(io);
1400}
1401
1402static void kcryptd_queue_crypt(struct dm_crypt_io *io)
1403{
1404 struct crypt_config *cc = io->cc;
1405
1406 INIT_WORK(&io->work, kcryptd_crypt);
1407 queue_work(cc->crypt_queue, &io->work);
1408}
1409
1410/*
1411 * Decode key from its hex representation
1412 */
1413static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
1414{
1415 char buffer[3];
1416 unsigned int i;
1417
1418 buffer[2] = '\0';
1419
1420 for (i = 0; i < size; i++) {
1421 buffer[0] = *hex++;
1422 buffer[1] = *hex++;
1423
1424 if (kstrtou8(buffer, 16, &key[i]))
1425 return -EINVAL;
1426 }
1427
1428 if (*hex != '\0')
1429 return -EINVAL;
1430
1431 return 0;
1432}
1433
1434static void crypt_free_tfms(struct crypt_config *cc)
1435{
1436 unsigned i;
1437
1438 if (!cc->tfms)
1439 return;
1440
1441 for (i = 0; i < cc->tfms_count; i++)
1442 if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) {
1443 crypto_free_skcipher(cc->tfms[i]);
1444 cc->tfms[i] = NULL;
1445 }
1446
1447 kfree(cc->tfms);
1448 cc->tfms = NULL;
1449}
1450
1451static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode)
1452{
1453 unsigned i;
1454 int err;
1455
1456 cc->tfms = kmalloc(cc->tfms_count * sizeof(struct crypto_skcipher *),
1457 GFP_KERNEL);
1458 if (!cc->tfms)
1459 return -ENOMEM;
1460
1461 for (i = 0; i < cc->tfms_count; i++) {
1462 cc->tfms[i] = crypto_alloc_skcipher(ciphermode, 0, 0);
1463 if (IS_ERR(cc->tfms[i])) {
1464 err = PTR_ERR(cc->tfms[i]);
1465 crypt_free_tfms(cc);
1466 return err;
1467 }
1468 }
1469
1470 return 0;
1471}
1472
1473static int crypt_setkey_allcpus(struct crypt_config *cc)
1474{
1475 unsigned subkey_size;
1476 int err = 0, i, r;
1477
1478 /* Ignore extra keys (which are used for IV etc) */
1479 subkey_size = (cc->key_size - cc->key_extra_size) >> ilog2(cc->tfms_count);
1480
1481 for (i = 0; i < cc->tfms_count; i++) {
1482 r = crypto_skcipher_setkey(cc->tfms[i],
1483 cc->key + (i * subkey_size),
1484 subkey_size);
1485 if (r)
1486 err = r;
1487 }
1488
1489 return err;
1490}
1491
1492static int crypt_set_key(struct crypt_config *cc, char *key)
1493{
1494 int r = -EINVAL;
1495 int key_string_len = strlen(key);
1496
1497 /* The key size may not be changed. */
1498 if (cc->key_size != (key_string_len >> 1))
1499 goto out;
1500
1501 /* Hyphen (which gives a key_size of zero) means there is no key. */
1502 if (!cc->key_size && strcmp(key, "-"))
1503 goto out;
1504
1505 if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
1506 goto out;
1507
1508 set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1509
1510 r = crypt_setkey_allcpus(cc);
1511
1512out:
1513 /* Hex key string not needed after here, so wipe it. */
1514 memset(key, '0', key_string_len);
1515
1516 return r;
1517}
1518
1519static int crypt_wipe_key(struct crypt_config *cc)
1520{
1521 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1522 memset(&cc->key, 0, cc->key_size * sizeof(u8));
1523
1524 return crypt_setkey_allcpus(cc);
1525}
1526
1527static void crypt_dtr(struct dm_target *ti)
1528{
1529 struct crypt_config *cc = ti->private;
1530
1531 ti->private = NULL;
1532
1533 if (!cc)
1534 return;
1535
1536 if (cc->write_thread) {
1537 spin_lock_irq(&cc->write_thread_wait.lock);
1538 set_bit(DM_CRYPT_EXIT_THREAD, &cc->flags);
1539 wake_up_locked(&cc->write_thread_wait);
1540 spin_unlock_irq(&cc->write_thread_wait.lock);
1541 kthread_stop(cc->write_thread);
1542 }
1543
1544 if (cc->io_queue)
1545 destroy_workqueue(cc->io_queue);
1546 if (cc->crypt_queue)
1547 destroy_workqueue(cc->crypt_queue);
1548
1549 crypt_free_tfms(cc);
1550
1551 if (cc->bs)
1552 bioset_free(cc->bs);
1553
1554 mempool_destroy(cc->page_pool);
1555 mempool_destroy(cc->req_pool);
1556
1557 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1558 cc->iv_gen_ops->dtr(cc);
1559
1560 if (cc->dev)
1561 dm_put_device(ti, cc->dev);
1562
1563 kzfree(cc->cipher);
1564 kzfree(cc->cipher_string);
1565
1566 /* Must zero key material before freeing */
1567 kzfree(cc);
1568}
1569
1570static int crypt_ctr_cipher(struct dm_target *ti,
1571 char *cipher_in, char *key)
1572{
1573 struct crypt_config *cc = ti->private;
1574 char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount;
1575 char *cipher_api = NULL;
1576 int ret = -EINVAL;
1577 char dummy;
1578
1579 /* Convert to crypto api definition? */
1580 if (strchr(cipher_in, '(')) {
1581 ti->error = "Bad cipher specification";
1582 return -EINVAL;
1583 }
1584
1585 cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
1586 if (!cc->cipher_string)
1587 goto bad_mem;
1588
1589 /*
1590 * Legacy dm-crypt cipher specification
1591 * cipher[:keycount]-mode-iv:ivopts
1592 */
1593 tmp = cipher_in;
1594 keycount = strsep(&tmp, "-");
1595 cipher = strsep(&keycount, ":");
1596
1597 if (!keycount)
1598 cc->tfms_count = 1;
1599 else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 ||
1600 !is_power_of_2(cc->tfms_count)) {
1601 ti->error = "Bad cipher key count specification";
1602 return -EINVAL;
1603 }
1604 cc->key_parts = cc->tfms_count;
1605 cc->key_extra_size = 0;
1606
1607 cc->cipher = kstrdup(cipher, GFP_KERNEL);
1608 if (!cc->cipher)
1609 goto bad_mem;
1610
1611 chainmode = strsep(&tmp, "-");
1612 ivopts = strsep(&tmp, "-");
1613 ivmode = strsep(&ivopts, ":");
1614
1615 if (tmp)
1616 DMWARN("Ignoring unexpected additional cipher options");
1617
1618 /*
1619 * For compatibility with the original dm-crypt mapping format, if
1620 * only the cipher name is supplied, use cbc-plain.
1621 */
1622 if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
1623 chainmode = "cbc";
1624 ivmode = "plain";
1625 }
1626
1627 if (strcmp(chainmode, "ecb") && !ivmode) {
1628 ti->error = "IV mechanism required";
1629 return -EINVAL;
1630 }
1631
1632 cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
1633 if (!cipher_api)
1634 goto bad_mem;
1635
1636 ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
1637 "%s(%s)", chainmode, cipher);
1638 if (ret < 0) {
1639 kfree(cipher_api);
1640 goto bad_mem;
1641 }
1642
1643 /* Allocate cipher */
1644 ret = crypt_alloc_tfms(cc, cipher_api);
1645 if (ret < 0) {
1646 ti->error = "Error allocating crypto tfm";
1647 goto bad;
1648 }
1649
1650 /* Initialize IV */
1651 cc->iv_size = crypto_skcipher_ivsize(any_tfm(cc));
1652 if (cc->iv_size)
1653 /* at least a 64 bit sector number should fit in our buffer */
1654 cc->iv_size = max(cc->iv_size,
1655 (unsigned int)(sizeof(u64) / sizeof(u8)));
1656 else if (ivmode) {
1657 DMWARN("Selected cipher does not support IVs");
1658 ivmode = NULL;
1659 }
1660
1661 /* Choose ivmode, see comments at iv code. */
1662 if (ivmode == NULL)
1663 cc->iv_gen_ops = NULL;
1664 else if (strcmp(ivmode, "plain") == 0)
1665 cc->iv_gen_ops = &crypt_iv_plain_ops;
1666 else if (strcmp(ivmode, "plain64") == 0)
1667 cc->iv_gen_ops = &crypt_iv_plain64_ops;
1668 else if (strcmp(ivmode, "essiv") == 0)
1669 cc->iv_gen_ops = &crypt_iv_essiv_ops;
1670 else if (strcmp(ivmode, "benbi") == 0)
1671 cc->iv_gen_ops = &crypt_iv_benbi_ops;
1672 else if (strcmp(ivmode, "null") == 0)
1673 cc->iv_gen_ops = &crypt_iv_null_ops;
1674 else if (strcmp(ivmode, "lmk") == 0) {
1675 cc->iv_gen_ops = &crypt_iv_lmk_ops;
1676 /*
1677 * Version 2 and 3 is recognised according
1678 * to length of provided multi-key string.
1679 * If present (version 3), last key is used as IV seed.
1680 * All keys (including IV seed) are always the same size.
1681 */
1682 if (cc->key_size % cc->key_parts) {
1683 cc->key_parts++;
1684 cc->key_extra_size = cc->key_size / cc->key_parts;
1685 }
1686 } else if (strcmp(ivmode, "tcw") == 0) {
1687 cc->iv_gen_ops = &crypt_iv_tcw_ops;
1688 cc->key_parts += 2; /* IV + whitening */
1689 cc->key_extra_size = cc->iv_size + TCW_WHITENING_SIZE;
1690 } else {
1691 ret = -EINVAL;
1692 ti->error = "Invalid IV mode";
1693 goto bad;
1694 }
1695
1696 /* Initialize and set key */
1697 ret = crypt_set_key(cc, key);
1698 if (ret < 0) {
1699 ti->error = "Error decoding and setting key";
1700 goto bad;
1701 }
1702
1703 /* Allocate IV */
1704 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
1705 ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
1706 if (ret < 0) {
1707 ti->error = "Error creating IV";
1708 goto bad;
1709 }
1710 }
1711
1712 /* Initialize IV (set keys for ESSIV etc) */
1713 if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
1714 ret = cc->iv_gen_ops->init(cc);
1715 if (ret < 0) {
1716 ti->error = "Error initialising IV";
1717 goto bad;
1718 }
1719 }
1720
1721 ret = 0;
1722bad:
1723 kfree(cipher_api);
1724 return ret;
1725
1726bad_mem:
1727 ti->error = "Cannot allocate cipher strings";
1728 return -ENOMEM;
1729}
1730
1731/*
1732 * Construct an encryption mapping:
1733 * <cipher> <key> <iv_offset> <dev_path> <start>
1734 */
1735static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1736{
1737 struct crypt_config *cc;
1738 unsigned int key_size, opt_params;
1739 unsigned long long tmpll;
1740 int ret;
1741 size_t iv_size_padding;
1742 struct dm_arg_set as;
1743 const char *opt_string;
1744 char dummy;
1745
1746 static struct dm_arg _args[] = {
1747 {0, 3, "Invalid number of feature args"},
1748 };
1749
1750 if (argc < 5) {
1751 ti->error = "Not enough arguments";
1752 return -EINVAL;
1753 }
1754
1755 key_size = strlen(argv[1]) >> 1;
1756
1757 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
1758 if (!cc) {
1759 ti->error = "Cannot allocate encryption context";
1760 return -ENOMEM;
1761 }
1762 cc->key_size = key_size;
1763
1764 ti->private = cc;
1765 ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
1766 if (ret < 0)
1767 goto bad;
1768
1769 cc->dmreq_start = sizeof(struct skcipher_request);
1770 cc->dmreq_start += crypto_skcipher_reqsize(any_tfm(cc));
1771 cc->dmreq_start = ALIGN(cc->dmreq_start, __alignof__(struct dm_crypt_request));
1772
1773 if (crypto_skcipher_alignmask(any_tfm(cc)) < CRYPTO_MINALIGN) {
1774 /* Allocate the padding exactly */
1775 iv_size_padding = -(cc->dmreq_start + sizeof(struct dm_crypt_request))
1776 & crypto_skcipher_alignmask(any_tfm(cc));
1777 } else {
1778 /*
1779 * If the cipher requires greater alignment than kmalloc
1780 * alignment, we don't know the exact position of the
1781 * initialization vector. We must assume worst case.
1782 */
1783 iv_size_padding = crypto_skcipher_alignmask(any_tfm(cc));
1784 }
1785
1786 ret = -ENOMEM;
1787 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1788 sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size);
1789 if (!cc->req_pool) {
1790 ti->error = "Cannot allocate crypt request mempool";
1791 goto bad;
1792 }
1793
1794 cc->per_bio_data_size = ti->per_io_data_size =
1795 ALIGN(sizeof(struct dm_crypt_io) + cc->dmreq_start +
1796 sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size,
1797 ARCH_KMALLOC_MINALIGN);
1798
1799 cc->page_pool = mempool_create_page_pool(BIO_MAX_PAGES, 0);
1800 if (!cc->page_pool) {
1801 ti->error = "Cannot allocate page mempool";
1802 goto bad;
1803 }
1804
1805 cc->bs = bioset_create(MIN_IOS, 0);
1806 if (!cc->bs) {
1807 ti->error = "Cannot allocate crypt bioset";
1808 goto bad;
1809 }
1810
1811 mutex_init(&cc->bio_alloc_lock);
1812
1813 ret = -EINVAL;
1814 if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) {
1815 ti->error = "Invalid iv_offset sector";
1816 goto bad;
1817 }
1818 cc->iv_offset = tmpll;
1819
1820 ret = dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev);
1821 if (ret) {
1822 ti->error = "Device lookup failed";
1823 goto bad;
1824 }
1825
1826 ret = -EINVAL;
1827 if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
1828 ti->error = "Invalid device sector";
1829 goto bad;
1830 }
1831 cc->start = tmpll;
1832
1833 argv += 5;
1834 argc -= 5;
1835
1836 /* Optional parameters */
1837 if (argc) {
1838 as.argc = argc;
1839 as.argv = argv;
1840
1841 ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1842 if (ret)
1843 goto bad;
1844
1845 ret = -EINVAL;
1846 while (opt_params--) {
1847 opt_string = dm_shift_arg(&as);
1848 if (!opt_string) {
1849 ti->error = "Not enough feature arguments";
1850 goto bad;
1851 }
1852
1853 if (!strcasecmp(opt_string, "allow_discards"))
1854 ti->num_discard_bios = 1;
1855
1856 else if (!strcasecmp(opt_string, "same_cpu_crypt"))
1857 set_bit(DM_CRYPT_SAME_CPU, &cc->flags);
1858
1859 else if (!strcasecmp(opt_string, "submit_from_crypt_cpus"))
1860 set_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags);
1861
1862 else {
1863 ti->error = "Invalid feature arguments";
1864 goto bad;
1865 }
1866 }
1867 }
1868
1869 ret = -ENOMEM;
1870 cc->io_queue = alloc_workqueue("kcryptd_io", WQ_MEM_RECLAIM, 1);
1871 if (!cc->io_queue) {
1872 ti->error = "Couldn't create kcryptd io queue";
1873 goto bad;
1874 }
1875
1876 if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
1877 cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1);
1878 else
1879 cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND,
1880 num_online_cpus());
1881 if (!cc->crypt_queue) {
1882 ti->error = "Couldn't create kcryptd queue";
1883 goto bad;
1884 }
1885
1886 init_waitqueue_head(&cc->write_thread_wait);
1887 cc->write_tree = RB_ROOT;
1888
1889 cc->write_thread = kthread_create(dmcrypt_write, cc, "dmcrypt_write");
1890 if (IS_ERR(cc->write_thread)) {
1891 ret = PTR_ERR(cc->write_thread);
1892 cc->write_thread = NULL;
1893 ti->error = "Couldn't spawn write thread";
1894 goto bad;
1895 }
1896 wake_up_process(cc->write_thread);
1897
1898 ti->num_flush_bios = 1;
1899 ti->discard_zeroes_data_unsupported = true;
1900
1901 return 0;
1902
1903bad:
1904 crypt_dtr(ti);
1905 return ret;
1906}
1907
1908static int crypt_map(struct dm_target *ti, struct bio *bio)
1909{
1910 struct dm_crypt_io *io;
1911 struct crypt_config *cc = ti->private;
1912
1913 /*
1914 * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues.
1915 * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight
1916 * - for REQ_DISCARD caller must use flush if IO ordering matters
1917 */
1918 if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) {
1919 bio->bi_bdev = cc->dev->bdev;
1920 if (bio_sectors(bio))
1921 bio->bi_iter.bi_sector = cc->start +
1922 dm_target_offset(ti, bio->bi_iter.bi_sector);
1923 return DM_MAPIO_REMAPPED;
1924 }
1925
1926 io = dm_per_bio_data(bio, cc->per_bio_data_size);
1927 crypt_io_init(io, cc, bio, dm_target_offset(ti, bio->bi_iter.bi_sector));
1928 io->ctx.req = (struct skcipher_request *)(io + 1);
1929
1930 if (bio_data_dir(io->base_bio) == READ) {
1931 if (kcryptd_io_read(io, GFP_NOWAIT))
1932 kcryptd_queue_read(io);
1933 } else
1934 kcryptd_queue_crypt(io);
1935
1936 return DM_MAPIO_SUBMITTED;
1937}
1938
1939static void crypt_status(struct dm_target *ti, status_type_t type,
1940 unsigned status_flags, char *result, unsigned maxlen)
1941{
1942 struct crypt_config *cc = ti->private;
1943 unsigned i, sz = 0;
1944 int num_feature_args = 0;
1945
1946 switch (type) {
1947 case STATUSTYPE_INFO:
1948 result[0] = '\0';
1949 break;
1950
1951 case STATUSTYPE_TABLE:
1952 DMEMIT("%s ", cc->cipher_string);
1953
1954 if (cc->key_size > 0)
1955 for (i = 0; i < cc->key_size; i++)
1956 DMEMIT("%02x", cc->key[i]);
1957 else
1958 DMEMIT("-");
1959
1960 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1961 cc->dev->name, (unsigned long long)cc->start);
1962
1963 num_feature_args += !!ti->num_discard_bios;
1964 num_feature_args += test_bit(DM_CRYPT_SAME_CPU, &cc->flags);
1965 num_feature_args += test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags);
1966 if (num_feature_args) {
1967 DMEMIT(" %d", num_feature_args);
1968 if (ti->num_discard_bios)
1969 DMEMIT(" allow_discards");
1970 if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
1971 DMEMIT(" same_cpu_crypt");
1972 if (test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags))
1973 DMEMIT(" submit_from_crypt_cpus");
1974 }
1975
1976 break;
1977 }
1978}
1979
1980static void crypt_postsuspend(struct dm_target *ti)
1981{
1982 struct crypt_config *cc = ti->private;
1983
1984 set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1985}
1986
1987static int crypt_preresume(struct dm_target *ti)
1988{
1989 struct crypt_config *cc = ti->private;
1990
1991 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1992 DMERR("aborting resume - crypt key is not set.");
1993 return -EAGAIN;
1994 }
1995
1996 return 0;
1997}
1998
1999static void crypt_resume(struct dm_target *ti)
2000{
2001 struct crypt_config *cc = ti->private;
2002
2003 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
2004}
2005
2006/* Message interface
2007 * key set <key>
2008 * key wipe
2009 */
2010static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
2011{
2012 struct crypt_config *cc = ti->private;
2013 int ret = -EINVAL;
2014
2015 if (argc < 2)
2016 goto error;
2017
2018 if (!strcasecmp(argv[0], "key")) {
2019 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
2020 DMWARN("not suspended during key manipulation.");
2021 return -EINVAL;
2022 }
2023 if (argc == 3 && !strcasecmp(argv[1], "set")) {
2024 ret = crypt_set_key(cc, argv[2]);
2025 if (ret)
2026 return ret;
2027 if (cc->iv_gen_ops && cc->iv_gen_ops->init)
2028 ret = cc->iv_gen_ops->init(cc);
2029 return ret;
2030 }
2031 if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
2032 if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
2033 ret = cc->iv_gen_ops->wipe(cc);
2034 if (ret)
2035 return ret;
2036 }
2037 return crypt_wipe_key(cc);
2038 }
2039 }
2040
2041error:
2042 DMWARN("unrecognised message received.");
2043 return -EINVAL;
2044}
2045
2046static int crypt_iterate_devices(struct dm_target *ti,
2047 iterate_devices_callout_fn fn, void *data)
2048{
2049 struct crypt_config *cc = ti->private;
2050
2051 return fn(ti, cc->dev, cc->start, ti->len, data);
2052}
2053
2054static void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits)
2055{
2056 /*
2057 * Unfortunate constraint that is required to avoid the potential
2058 * for exceeding underlying device's max_segments limits -- due to
2059 * crypt_alloc_buffer() possibly allocating pages for the encryption
2060 * bio that are not as physically contiguous as the original bio.
2061 */
2062 limits->max_segment_size = PAGE_SIZE;
2063}
2064
2065static struct target_type crypt_target = {
2066 .name = "crypt",
2067 .version = {1, 14, 1},
2068 .module = THIS_MODULE,
2069 .ctr = crypt_ctr,
2070 .dtr = crypt_dtr,
2071 .map = crypt_map,
2072 .status = crypt_status,
2073 .postsuspend = crypt_postsuspend,
2074 .preresume = crypt_preresume,
2075 .resume = crypt_resume,
2076 .message = crypt_message,
2077 .iterate_devices = crypt_iterate_devices,
2078 .io_hints = crypt_io_hints,
2079};
2080
2081static int __init dm_crypt_init(void)
2082{
2083 int r;
2084
2085 r = dm_register_target(&crypt_target);
2086 if (r < 0)
2087 DMERR("register failed %d", r);
2088
2089 return r;
2090}
2091
2092static void __exit dm_crypt_exit(void)
2093{
2094 dm_unregister_target(&crypt_target);
2095}
2096
2097module_init(dm_crypt_init);
2098module_exit(dm_crypt_exit);
2099
2100MODULE_AUTHOR("Jana Saout <jana@saout.de>");
2101MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
2102MODULE_LICENSE("GPL");
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#define MIN_BIO_PAGES 8
180
181static struct kmem_cache *_crypt_io_pool;
182
183static void clone_init(struct dm_crypt_io *, struct bio *);
184static void kcryptd_queue_crypt(struct dm_crypt_io *io);
185static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq);
186
187static struct crypt_cpu *this_crypt_config(struct crypt_config *cc)
188{
189 return this_cpu_ptr(cc->cpu);
190}
191
192/*
193 * Use this to access cipher attributes that are the same for each CPU.
194 */
195static struct crypto_ablkcipher *any_tfm(struct crypt_config *cc)
196{
197 return __this_cpu_ptr(cc->cpu)->tfms[0];
198}
199
200/*
201 * Different IV generation algorithms:
202 *
203 * plain: the initial vector is the 32-bit little-endian version of the sector
204 * number, padded with zeros if necessary.
205 *
206 * plain64: the initial vector is the 64-bit little-endian version of the sector
207 * number, padded with zeros if necessary.
208 *
209 * essiv: "encrypted sector|salt initial vector", the sector number is
210 * encrypted with the bulk cipher using a salt as key. The salt
211 * should be derived from the bulk cipher's key via hashing.
212 *
213 * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
214 * (needed for LRW-32-AES and possible other narrow block modes)
215 *
216 * null: the initial vector is always zero. Provides compatibility with
217 * obsolete loop_fish2 devices. Do not use for new devices.
218 *
219 * lmk: Compatible implementation of the block chaining mode used
220 * by the Loop-AES block device encryption system
221 * designed by Jari Ruusu. See http://loop-aes.sourceforge.net/
222 * It operates on full 512 byte sectors and uses CBC
223 * with an IV derived from the sector number, the data and
224 * optionally extra IV seed.
225 * This means that after decryption the first block
226 * of sector must be tweaked according to decrypted data.
227 * Loop-AES can use three encryption schemes:
228 * version 1: is plain aes-cbc mode
229 * version 2: uses 64 multikey scheme with lmk IV generator
230 * version 3: the same as version 2 with additional IV seed
231 * (it uses 65 keys, last key is used as IV seed)
232 *
233 * plumb: unimplemented, see:
234 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
235 */
236
237static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv,
238 struct dm_crypt_request *dmreq)
239{
240 memset(iv, 0, cc->iv_size);
241 *(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff);
242
243 return 0;
244}
245
246static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
247 struct dm_crypt_request *dmreq)
248{
249 memset(iv, 0, cc->iv_size);
250 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
251
252 return 0;
253}
254
255/* Initialise ESSIV - compute salt but no local memory allocations */
256static int crypt_iv_essiv_init(struct crypt_config *cc)
257{
258 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
259 struct hash_desc desc;
260 struct scatterlist sg;
261 struct crypto_cipher *essiv_tfm;
262 int err, cpu;
263
264 sg_init_one(&sg, cc->key, cc->key_size);
265 desc.tfm = essiv->hash_tfm;
266 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
267
268 err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt);
269 if (err)
270 return err;
271
272 for_each_possible_cpu(cpu) {
273 essiv_tfm = per_cpu_ptr(cc->cpu, cpu)->iv_private,
274
275 err = crypto_cipher_setkey(essiv_tfm, essiv->salt,
276 crypto_hash_digestsize(essiv->hash_tfm));
277 if (err)
278 return err;
279 }
280
281 return 0;
282}
283
284/* Wipe salt and reset key derived from volume key */
285static int crypt_iv_essiv_wipe(struct crypt_config *cc)
286{
287 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
288 unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm);
289 struct crypto_cipher *essiv_tfm;
290 int cpu, r, err = 0;
291
292 memset(essiv->salt, 0, salt_size);
293
294 for_each_possible_cpu(cpu) {
295 essiv_tfm = per_cpu_ptr(cc->cpu, cpu)->iv_private;
296 r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size);
297 if (r)
298 err = r;
299 }
300
301 return err;
302}
303
304/* Set up per cpu cipher state */
305static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc,
306 struct dm_target *ti,
307 u8 *salt, unsigned saltsize)
308{
309 struct crypto_cipher *essiv_tfm;
310 int err;
311
312 /* Setup the essiv_tfm with the given salt */
313 essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
314 if (IS_ERR(essiv_tfm)) {
315 ti->error = "Error allocating crypto tfm for ESSIV";
316 return essiv_tfm;
317 }
318
319 if (crypto_cipher_blocksize(essiv_tfm) !=
320 crypto_ablkcipher_ivsize(any_tfm(cc))) {
321 ti->error = "Block size of ESSIV cipher does "
322 "not match IV size of block cipher";
323 crypto_free_cipher(essiv_tfm);
324 return ERR_PTR(-EINVAL);
325 }
326
327 err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
328 if (err) {
329 ti->error = "Failed to set key for ESSIV cipher";
330 crypto_free_cipher(essiv_tfm);
331 return ERR_PTR(err);
332 }
333
334 return essiv_tfm;
335}
336
337static void crypt_iv_essiv_dtr(struct crypt_config *cc)
338{
339 int cpu;
340 struct crypt_cpu *cpu_cc;
341 struct crypto_cipher *essiv_tfm;
342 struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
343
344 crypto_free_hash(essiv->hash_tfm);
345 essiv->hash_tfm = NULL;
346
347 kzfree(essiv->salt);
348 essiv->salt = NULL;
349
350 for_each_possible_cpu(cpu) {
351 cpu_cc = per_cpu_ptr(cc->cpu, cpu);
352 essiv_tfm = cpu_cc->iv_private;
353
354 if (essiv_tfm)
355 crypto_free_cipher(essiv_tfm);
356
357 cpu_cc->iv_private = NULL;
358 }
359}
360
361static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
362 const char *opts)
363{
364 struct crypto_cipher *essiv_tfm = NULL;
365 struct crypto_hash *hash_tfm = NULL;
366 u8 *salt = NULL;
367 int err, cpu;
368
369 if (!opts) {
370 ti->error = "Digest algorithm missing for ESSIV mode";
371 return -EINVAL;
372 }
373
374 /* Allocate hash algorithm */
375 hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
376 if (IS_ERR(hash_tfm)) {
377 ti->error = "Error initializing ESSIV hash";
378 err = PTR_ERR(hash_tfm);
379 goto bad;
380 }
381
382 salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL);
383 if (!salt) {
384 ti->error = "Error kmallocing salt storage in ESSIV";
385 err = -ENOMEM;
386 goto bad;
387 }
388
389 cc->iv_gen_private.essiv.salt = salt;
390 cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
391
392 for_each_possible_cpu(cpu) {
393 essiv_tfm = setup_essiv_cpu(cc, ti, salt,
394 crypto_hash_digestsize(hash_tfm));
395 if (IS_ERR(essiv_tfm)) {
396 crypt_iv_essiv_dtr(cc);
397 return PTR_ERR(essiv_tfm);
398 }
399 per_cpu_ptr(cc->cpu, cpu)->iv_private = essiv_tfm;
400 }
401
402 return 0;
403
404bad:
405 if (hash_tfm && !IS_ERR(hash_tfm))
406 crypto_free_hash(hash_tfm);
407 kfree(salt);
408 return err;
409}
410
411static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv,
412 struct dm_crypt_request *dmreq)
413{
414 struct crypto_cipher *essiv_tfm = this_crypt_config(cc)->iv_private;
415
416 memset(iv, 0, cc->iv_size);
417 *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
418 crypto_cipher_encrypt_one(essiv_tfm, iv, iv);
419
420 return 0;
421}
422
423static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
424 const char *opts)
425{
426 unsigned bs = crypto_ablkcipher_blocksize(any_tfm(cc));
427 int log = ilog2(bs);
428
429 /* we need to calculate how far we must shift the sector count
430 * to get the cipher block count, we use this shift in _gen */
431
432 if (1 << log != bs) {
433 ti->error = "cypher blocksize is not a power of 2";
434 return -EINVAL;
435 }
436
437 if (log > 9) {
438 ti->error = "cypher blocksize is > 512";
439 return -EINVAL;
440 }
441
442 cc->iv_gen_private.benbi.shift = 9 - log;
443
444 return 0;
445}
446
447static void crypt_iv_benbi_dtr(struct crypt_config *cc)
448{
449}
450
451static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv,
452 struct dm_crypt_request *dmreq)
453{
454 __be64 val;
455
456 memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
457
458 val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1);
459 put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
460
461 return 0;
462}
463
464static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv,
465 struct dm_crypt_request *dmreq)
466{
467 memset(iv, 0, cc->iv_size);
468
469 return 0;
470}
471
472static void crypt_iv_lmk_dtr(struct crypt_config *cc)
473{
474 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
475
476 if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm))
477 crypto_free_shash(lmk->hash_tfm);
478 lmk->hash_tfm = NULL;
479
480 kzfree(lmk->seed);
481 lmk->seed = NULL;
482}
483
484static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti,
485 const char *opts)
486{
487 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
488
489 lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0);
490 if (IS_ERR(lmk->hash_tfm)) {
491 ti->error = "Error initializing LMK hash";
492 return PTR_ERR(lmk->hash_tfm);
493 }
494
495 /* No seed in LMK version 2 */
496 if (cc->key_parts == cc->tfms_count) {
497 lmk->seed = NULL;
498 return 0;
499 }
500
501 lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL);
502 if (!lmk->seed) {
503 crypt_iv_lmk_dtr(cc);
504 ti->error = "Error kmallocing seed storage in LMK";
505 return -ENOMEM;
506 }
507
508 return 0;
509}
510
511static int crypt_iv_lmk_init(struct crypt_config *cc)
512{
513 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
514 int subkey_size = cc->key_size / cc->key_parts;
515
516 /* LMK seed is on the position of LMK_KEYS + 1 key */
517 if (lmk->seed)
518 memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size),
519 crypto_shash_digestsize(lmk->hash_tfm));
520
521 return 0;
522}
523
524static int crypt_iv_lmk_wipe(struct crypt_config *cc)
525{
526 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
527
528 if (lmk->seed)
529 memset(lmk->seed, 0, LMK_SEED_SIZE);
530
531 return 0;
532}
533
534static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv,
535 struct dm_crypt_request *dmreq,
536 u8 *data)
537{
538 struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
539 struct {
540 struct shash_desc desc;
541 char ctx[crypto_shash_descsize(lmk->hash_tfm)];
542 } sdesc;
543 struct md5_state md5state;
544 u32 buf[4];
545 int i, r;
546
547 sdesc.desc.tfm = lmk->hash_tfm;
548 sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
549
550 r = crypto_shash_init(&sdesc.desc);
551 if (r)
552 return r;
553
554 if (lmk->seed) {
555 r = crypto_shash_update(&sdesc.desc, lmk->seed, LMK_SEED_SIZE);
556 if (r)
557 return r;
558 }
559
560 /* Sector is always 512B, block size 16, add data of blocks 1-31 */
561 r = crypto_shash_update(&sdesc.desc, data + 16, 16 * 31);
562 if (r)
563 return r;
564
565 /* Sector is cropped to 56 bits here */
566 buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF);
567 buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000);
568 buf[2] = cpu_to_le32(4024);
569 buf[3] = 0;
570 r = crypto_shash_update(&sdesc.desc, (u8 *)buf, sizeof(buf));
571 if (r)
572 return r;
573
574 /* No MD5 padding here */
575 r = crypto_shash_export(&sdesc.desc, &md5state);
576 if (r)
577 return r;
578
579 for (i = 0; i < MD5_HASH_WORDS; i++)
580 __cpu_to_le32s(&md5state.hash[i]);
581 memcpy(iv, &md5state.hash, cc->iv_size);
582
583 return 0;
584}
585
586static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv,
587 struct dm_crypt_request *dmreq)
588{
589 u8 *src;
590 int r = 0;
591
592 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) {
593 src = kmap_atomic(sg_page(&dmreq->sg_in), KM_USER0);
594 r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset);
595 kunmap_atomic(src, KM_USER0);
596 } else
597 memset(iv, 0, cc->iv_size);
598
599 return r;
600}
601
602static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv,
603 struct dm_crypt_request *dmreq)
604{
605 u8 *dst;
606 int r;
607
608 if (bio_data_dir(dmreq->ctx->bio_in) == WRITE)
609 return 0;
610
611 dst = kmap_atomic(sg_page(&dmreq->sg_out), KM_USER0);
612 r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset);
613
614 /* Tweak the first block of plaintext sector */
615 if (!r)
616 crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size);
617
618 kunmap_atomic(dst, KM_USER0);
619 return r;
620}
621
622static struct crypt_iv_operations crypt_iv_plain_ops = {
623 .generator = crypt_iv_plain_gen
624};
625
626static struct crypt_iv_operations crypt_iv_plain64_ops = {
627 .generator = crypt_iv_plain64_gen
628};
629
630static struct crypt_iv_operations crypt_iv_essiv_ops = {
631 .ctr = crypt_iv_essiv_ctr,
632 .dtr = crypt_iv_essiv_dtr,
633 .init = crypt_iv_essiv_init,
634 .wipe = crypt_iv_essiv_wipe,
635 .generator = crypt_iv_essiv_gen
636};
637
638static struct crypt_iv_operations crypt_iv_benbi_ops = {
639 .ctr = crypt_iv_benbi_ctr,
640 .dtr = crypt_iv_benbi_dtr,
641 .generator = crypt_iv_benbi_gen
642};
643
644static struct crypt_iv_operations crypt_iv_null_ops = {
645 .generator = crypt_iv_null_gen
646};
647
648static struct crypt_iv_operations crypt_iv_lmk_ops = {
649 .ctr = crypt_iv_lmk_ctr,
650 .dtr = crypt_iv_lmk_dtr,
651 .init = crypt_iv_lmk_init,
652 .wipe = crypt_iv_lmk_wipe,
653 .generator = crypt_iv_lmk_gen,
654 .post = crypt_iv_lmk_post
655};
656
657static void crypt_convert_init(struct crypt_config *cc,
658 struct convert_context *ctx,
659 struct bio *bio_out, struct bio *bio_in,
660 sector_t sector)
661{
662 ctx->bio_in = bio_in;
663 ctx->bio_out = bio_out;
664 ctx->offset_in = 0;
665 ctx->offset_out = 0;
666 ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
667 ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
668 ctx->sector = sector + cc->iv_offset;
669 init_completion(&ctx->restart);
670}
671
672static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
673 struct ablkcipher_request *req)
674{
675 return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
676}
677
678static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc,
679 struct dm_crypt_request *dmreq)
680{
681 return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start);
682}
683
684static u8 *iv_of_dmreq(struct crypt_config *cc,
685 struct dm_crypt_request *dmreq)
686{
687 return (u8 *)ALIGN((unsigned long)(dmreq + 1),
688 crypto_ablkcipher_alignmask(any_tfm(cc)) + 1);
689}
690
691static int crypt_convert_block(struct crypt_config *cc,
692 struct convert_context *ctx,
693 struct ablkcipher_request *req)
694{
695 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
696 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
697 struct dm_crypt_request *dmreq;
698 u8 *iv;
699 int r = 0;
700
701 dmreq = dmreq_of_req(cc, req);
702 iv = iv_of_dmreq(cc, dmreq);
703
704 dmreq->iv_sector = ctx->sector;
705 dmreq->ctx = ctx;
706 sg_init_table(&dmreq->sg_in, 1);
707 sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
708 bv_in->bv_offset + ctx->offset_in);
709
710 sg_init_table(&dmreq->sg_out, 1);
711 sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
712 bv_out->bv_offset + ctx->offset_out);
713
714 ctx->offset_in += 1 << SECTOR_SHIFT;
715 if (ctx->offset_in >= bv_in->bv_len) {
716 ctx->offset_in = 0;
717 ctx->idx_in++;
718 }
719
720 ctx->offset_out += 1 << SECTOR_SHIFT;
721 if (ctx->offset_out >= bv_out->bv_len) {
722 ctx->offset_out = 0;
723 ctx->idx_out++;
724 }
725
726 if (cc->iv_gen_ops) {
727 r = cc->iv_gen_ops->generator(cc, iv, dmreq);
728 if (r < 0)
729 return r;
730 }
731
732 ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
733 1 << SECTOR_SHIFT, iv);
734
735 if (bio_data_dir(ctx->bio_in) == WRITE)
736 r = crypto_ablkcipher_encrypt(req);
737 else
738 r = crypto_ablkcipher_decrypt(req);
739
740 if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
741 r = cc->iv_gen_ops->post(cc, iv, dmreq);
742
743 return r;
744}
745
746static void kcryptd_async_done(struct crypto_async_request *async_req,
747 int error);
748
749static void crypt_alloc_req(struct crypt_config *cc,
750 struct convert_context *ctx)
751{
752 struct crypt_cpu *this_cc = this_crypt_config(cc);
753 unsigned key_index = ctx->sector & (cc->tfms_count - 1);
754
755 if (!this_cc->req)
756 this_cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
757
758 ablkcipher_request_set_tfm(this_cc->req, this_cc->tfms[key_index]);
759 ablkcipher_request_set_callback(this_cc->req,
760 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
761 kcryptd_async_done, dmreq_of_req(cc, this_cc->req));
762}
763
764/*
765 * Encrypt / decrypt data from one bio to another one (can be the same one)
766 */
767static int crypt_convert(struct crypt_config *cc,
768 struct convert_context *ctx)
769{
770 struct crypt_cpu *this_cc = this_crypt_config(cc);
771 int r;
772
773 atomic_set(&ctx->pending, 1);
774
775 while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
776 ctx->idx_out < ctx->bio_out->bi_vcnt) {
777
778 crypt_alloc_req(cc, ctx);
779
780 atomic_inc(&ctx->pending);
781
782 r = crypt_convert_block(cc, ctx, this_cc->req);
783
784 switch (r) {
785 /* async */
786 case -EBUSY:
787 wait_for_completion(&ctx->restart);
788 INIT_COMPLETION(ctx->restart);
789 /* fall through*/
790 case -EINPROGRESS:
791 this_cc->req = NULL;
792 ctx->sector++;
793 continue;
794
795 /* sync */
796 case 0:
797 atomic_dec(&ctx->pending);
798 ctx->sector++;
799 cond_resched();
800 continue;
801
802 /* error */
803 default:
804 atomic_dec(&ctx->pending);
805 return r;
806 }
807 }
808
809 return 0;
810}
811
812static void dm_crypt_bio_destructor(struct bio *bio)
813{
814 struct dm_crypt_io *io = bio->bi_private;
815 struct crypt_config *cc = io->target->private;
816
817 bio_free(bio, cc->bs);
818}
819
820/*
821 * Generate a new unfragmented bio with the given size
822 * This should never violate the device limitations
823 * May return a smaller bio when running out of pages, indicated by
824 * *out_of_pages set to 1.
825 */
826static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
827 unsigned *out_of_pages)
828{
829 struct crypt_config *cc = io->target->private;
830 struct bio *clone;
831 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
832 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
833 unsigned i, len;
834 struct page *page;
835
836 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
837 if (!clone)
838 return NULL;
839
840 clone_init(io, clone);
841 *out_of_pages = 0;
842
843 for (i = 0; i < nr_iovecs; i++) {
844 page = mempool_alloc(cc->page_pool, gfp_mask);
845 if (!page) {
846 *out_of_pages = 1;
847 break;
848 }
849
850 /*
851 * if additional pages cannot be allocated without waiting,
852 * return a partially allocated bio, the caller will then try
853 * to allocate additional bios while submitting this partial bio
854 */
855 if (i == (MIN_BIO_PAGES - 1))
856 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
857
858 len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
859
860 if (!bio_add_page(clone, page, len, 0)) {
861 mempool_free(page, cc->page_pool);
862 break;
863 }
864
865 size -= len;
866 }
867
868 if (!clone->bi_size) {
869 bio_put(clone);
870 return NULL;
871 }
872
873 return clone;
874}
875
876static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
877{
878 unsigned int i;
879 struct bio_vec *bv;
880
881 for (i = 0; i < clone->bi_vcnt; i++) {
882 bv = bio_iovec_idx(clone, i);
883 BUG_ON(!bv->bv_page);
884 mempool_free(bv->bv_page, cc->page_pool);
885 bv->bv_page = NULL;
886 }
887}
888
889static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti,
890 struct bio *bio, sector_t sector)
891{
892 struct crypt_config *cc = ti->private;
893 struct dm_crypt_io *io;
894
895 io = mempool_alloc(cc->io_pool, GFP_NOIO);
896 io->target = ti;
897 io->base_bio = bio;
898 io->sector = sector;
899 io->error = 0;
900 io->base_io = NULL;
901 atomic_set(&io->pending, 0);
902
903 return io;
904}
905
906static void crypt_inc_pending(struct dm_crypt_io *io)
907{
908 atomic_inc(&io->pending);
909}
910
911/*
912 * One of the bios was finished. Check for completion of
913 * the whole request and correctly clean up the buffer.
914 * If base_io is set, wait for the last fragment to complete.
915 */
916static void crypt_dec_pending(struct dm_crypt_io *io)
917{
918 struct crypt_config *cc = io->target->private;
919 struct bio *base_bio = io->base_bio;
920 struct dm_crypt_io *base_io = io->base_io;
921 int error = io->error;
922
923 if (!atomic_dec_and_test(&io->pending))
924 return;
925
926 mempool_free(io, cc->io_pool);
927
928 if (likely(!base_io))
929 bio_endio(base_bio, error);
930 else {
931 if (error && !base_io->error)
932 base_io->error = error;
933 crypt_dec_pending(base_io);
934 }
935}
936
937/*
938 * kcryptd/kcryptd_io:
939 *
940 * Needed because it would be very unwise to do decryption in an
941 * interrupt context.
942 *
943 * kcryptd performs the actual encryption or decryption.
944 *
945 * kcryptd_io performs the IO submission.
946 *
947 * They must be separated as otherwise the final stages could be
948 * starved by new requests which can block in the first stages due
949 * to memory allocation.
950 *
951 * The work is done per CPU global for all dm-crypt instances.
952 * They should not depend on each other and do not block.
953 */
954static void crypt_endio(struct bio *clone, int error)
955{
956 struct dm_crypt_io *io = clone->bi_private;
957 struct crypt_config *cc = io->target->private;
958 unsigned rw = bio_data_dir(clone);
959
960 if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
961 error = -EIO;
962
963 /*
964 * free the processed pages
965 */
966 if (rw == WRITE)
967 crypt_free_buffer_pages(cc, clone);
968
969 bio_put(clone);
970
971 if (rw == READ && !error) {
972 kcryptd_queue_crypt(io);
973 return;
974 }
975
976 if (unlikely(error))
977 io->error = error;
978
979 crypt_dec_pending(io);
980}
981
982static void clone_init(struct dm_crypt_io *io, struct bio *clone)
983{
984 struct crypt_config *cc = io->target->private;
985
986 clone->bi_private = io;
987 clone->bi_end_io = crypt_endio;
988 clone->bi_bdev = cc->dev->bdev;
989 clone->bi_rw = io->base_bio->bi_rw;
990 clone->bi_destructor = dm_crypt_bio_destructor;
991}
992
993static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
994{
995 struct crypt_config *cc = io->target->private;
996 struct bio *base_bio = io->base_bio;
997 struct bio *clone;
998
999 /*
1000 * The block layer might modify the bvec array, so always
1001 * copy the required bvecs because we need the original
1002 * one in order to decrypt the whole bio data *afterwards*.
1003 */
1004 clone = bio_alloc_bioset(gfp, bio_segments(base_bio), cc->bs);
1005 if (!clone)
1006 return 1;
1007
1008 crypt_inc_pending(io);
1009
1010 clone_init(io, clone);
1011 clone->bi_idx = 0;
1012 clone->bi_vcnt = bio_segments(base_bio);
1013 clone->bi_size = base_bio->bi_size;
1014 clone->bi_sector = cc->start + io->sector;
1015 memcpy(clone->bi_io_vec, bio_iovec(base_bio),
1016 sizeof(struct bio_vec) * clone->bi_vcnt);
1017
1018 generic_make_request(clone);
1019 return 0;
1020}
1021
1022static void kcryptd_io_write(struct dm_crypt_io *io)
1023{
1024 struct bio *clone = io->ctx.bio_out;
1025 generic_make_request(clone);
1026}
1027
1028static void kcryptd_io(struct work_struct *work)
1029{
1030 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1031
1032 if (bio_data_dir(io->base_bio) == READ) {
1033 crypt_inc_pending(io);
1034 if (kcryptd_io_read(io, GFP_NOIO))
1035 io->error = -ENOMEM;
1036 crypt_dec_pending(io);
1037 } else
1038 kcryptd_io_write(io);
1039}
1040
1041static void kcryptd_queue_io(struct dm_crypt_io *io)
1042{
1043 struct crypt_config *cc = io->target->private;
1044
1045 INIT_WORK(&io->work, kcryptd_io);
1046 queue_work(cc->io_queue, &io->work);
1047}
1048
1049static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
1050 int error, int async)
1051{
1052 struct bio *clone = io->ctx.bio_out;
1053 struct crypt_config *cc = io->target->private;
1054
1055 if (unlikely(error < 0)) {
1056 crypt_free_buffer_pages(cc, clone);
1057 bio_put(clone);
1058 io->error = -EIO;
1059 crypt_dec_pending(io);
1060 return;
1061 }
1062
1063 /* crypt_convert should have filled the clone bio */
1064 BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
1065
1066 clone->bi_sector = cc->start + io->sector;
1067
1068 if (async)
1069 kcryptd_queue_io(io);
1070 else
1071 generic_make_request(clone);
1072}
1073
1074static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
1075{
1076 struct crypt_config *cc = io->target->private;
1077 struct bio *clone;
1078 struct dm_crypt_io *new_io;
1079 int crypt_finished;
1080 unsigned out_of_pages = 0;
1081 unsigned remaining = io->base_bio->bi_size;
1082 sector_t sector = io->sector;
1083 int r;
1084
1085 /*
1086 * Prevent io from disappearing until this function completes.
1087 */
1088 crypt_inc_pending(io);
1089 crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
1090
1091 /*
1092 * The allocated buffers can be smaller than the whole bio,
1093 * so repeat the whole process until all the data can be handled.
1094 */
1095 while (remaining) {
1096 clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
1097 if (unlikely(!clone)) {
1098 io->error = -ENOMEM;
1099 break;
1100 }
1101
1102 io->ctx.bio_out = clone;
1103 io->ctx.idx_out = 0;
1104
1105 remaining -= clone->bi_size;
1106 sector += bio_sectors(clone);
1107
1108 crypt_inc_pending(io);
1109 r = crypt_convert(cc, &io->ctx);
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, r, 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, int error)
1166{
1167 if (unlikely(error < 0))
1168 io->error = -EIO;
1169
1170 crypt_dec_pending(io);
1171}
1172
1173static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
1174{
1175 struct crypt_config *cc = io->target->private;
1176 int r = 0;
1177
1178 crypt_inc_pending(io);
1179
1180 crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
1181 io->sector);
1182
1183 r = crypt_convert(cc, &io->ctx);
1184
1185 if (atomic_dec_and_test(&io->ctx.pending))
1186 kcryptd_crypt_read_done(io, r);
1187
1188 crypt_dec_pending(io);
1189}
1190
1191static void kcryptd_async_done(struct crypto_async_request *async_req,
1192 int error)
1193{
1194 struct dm_crypt_request *dmreq = async_req->data;
1195 struct convert_context *ctx = dmreq->ctx;
1196 struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
1197 struct crypt_config *cc = io->target->private;
1198
1199 if (error == -EINPROGRESS) {
1200 complete(&ctx->restart);
1201 return;
1202 }
1203
1204 if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
1205 error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
1206
1207 mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool);
1208
1209 if (!atomic_dec_and_test(&ctx->pending))
1210 return;
1211
1212 if (bio_data_dir(io->base_bio) == READ)
1213 kcryptd_crypt_read_done(io, error);
1214 else
1215 kcryptd_crypt_write_io_submit(io, error, 1);
1216}
1217
1218static void kcryptd_crypt(struct work_struct *work)
1219{
1220 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1221
1222 if (bio_data_dir(io->base_bio) == READ)
1223 kcryptd_crypt_read_convert(io);
1224 else
1225 kcryptd_crypt_write_convert(io);
1226}
1227
1228static void kcryptd_queue_crypt(struct dm_crypt_io *io)
1229{
1230 struct crypt_config *cc = io->target->private;
1231
1232 INIT_WORK(&io->work, kcryptd_crypt);
1233 queue_work(cc->crypt_queue, &io->work);
1234}
1235
1236/*
1237 * Decode key from its hex representation
1238 */
1239static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
1240{
1241 char buffer[3];
1242 char *endp;
1243 unsigned int i;
1244
1245 buffer[2] = '\0';
1246
1247 for (i = 0; i < size; i++) {
1248 buffer[0] = *hex++;
1249 buffer[1] = *hex++;
1250
1251 key[i] = (u8)simple_strtoul(buffer, &endp, 16);
1252
1253 if (endp != &buffer[2])
1254 return -EINVAL;
1255 }
1256
1257 if (*hex != '\0')
1258 return -EINVAL;
1259
1260 return 0;
1261}
1262
1263/*
1264 * Encode key into its hex representation
1265 */
1266static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
1267{
1268 unsigned int i;
1269
1270 for (i = 0; i < size; i++) {
1271 sprintf(hex, "%02x", *key);
1272 hex += 2;
1273 key++;
1274 }
1275}
1276
1277static void crypt_free_tfms(struct crypt_config *cc, int cpu)
1278{
1279 struct crypt_cpu *cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1280 unsigned i;
1281
1282 for (i = 0; i < cc->tfms_count; i++)
1283 if (cpu_cc->tfms[i] && !IS_ERR(cpu_cc->tfms[i])) {
1284 crypto_free_ablkcipher(cpu_cc->tfms[i]);
1285 cpu_cc->tfms[i] = NULL;
1286 }
1287}
1288
1289static int crypt_alloc_tfms(struct crypt_config *cc, int cpu, char *ciphermode)
1290{
1291 struct crypt_cpu *cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1292 unsigned i;
1293 int err;
1294
1295 for (i = 0; i < cc->tfms_count; i++) {
1296 cpu_cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0);
1297 if (IS_ERR(cpu_cc->tfms[i])) {
1298 err = PTR_ERR(cpu_cc->tfms[i]);
1299 crypt_free_tfms(cc, cpu);
1300 return err;
1301 }
1302 }
1303
1304 return 0;
1305}
1306
1307static int crypt_setkey_allcpus(struct crypt_config *cc)
1308{
1309 unsigned subkey_size = cc->key_size >> ilog2(cc->tfms_count);
1310 int cpu, err = 0, i, r;
1311
1312 for_each_possible_cpu(cpu) {
1313 for (i = 0; i < cc->tfms_count; i++) {
1314 r = crypto_ablkcipher_setkey(per_cpu_ptr(cc->cpu, cpu)->tfms[i],
1315 cc->key + (i * subkey_size), subkey_size);
1316 if (r)
1317 err = r;
1318 }
1319 }
1320
1321 return err;
1322}
1323
1324static int crypt_set_key(struct crypt_config *cc, char *key)
1325{
1326 int r = -EINVAL;
1327 int key_string_len = strlen(key);
1328
1329 /* The key size may not be changed. */
1330 if (cc->key_size != (key_string_len >> 1))
1331 goto out;
1332
1333 /* Hyphen (which gives a key_size of zero) means there is no key. */
1334 if (!cc->key_size && strcmp(key, "-"))
1335 goto out;
1336
1337 if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
1338 goto out;
1339
1340 set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1341
1342 r = crypt_setkey_allcpus(cc);
1343
1344out:
1345 /* Hex key string not needed after here, so wipe it. */
1346 memset(key, '0', key_string_len);
1347
1348 return r;
1349}
1350
1351static int crypt_wipe_key(struct crypt_config *cc)
1352{
1353 clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1354 memset(&cc->key, 0, cc->key_size * sizeof(u8));
1355
1356 return crypt_setkey_allcpus(cc);
1357}
1358
1359static void crypt_dtr(struct dm_target *ti)
1360{
1361 struct crypt_config *cc = ti->private;
1362 struct crypt_cpu *cpu_cc;
1363 int cpu;
1364
1365 ti->private = NULL;
1366
1367 if (!cc)
1368 return;
1369
1370 if (cc->io_queue)
1371 destroy_workqueue(cc->io_queue);
1372 if (cc->crypt_queue)
1373 destroy_workqueue(cc->crypt_queue);
1374
1375 if (cc->cpu)
1376 for_each_possible_cpu(cpu) {
1377 cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1378 if (cpu_cc->req)
1379 mempool_free(cpu_cc->req, cc->req_pool);
1380 crypt_free_tfms(cc, cpu);
1381 }
1382
1383 if (cc->bs)
1384 bioset_free(cc->bs);
1385
1386 if (cc->page_pool)
1387 mempool_destroy(cc->page_pool);
1388 if (cc->req_pool)
1389 mempool_destroy(cc->req_pool);
1390 if (cc->io_pool)
1391 mempool_destroy(cc->io_pool);
1392
1393 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1394 cc->iv_gen_ops->dtr(cc);
1395
1396 if (cc->dev)
1397 dm_put_device(ti, cc->dev);
1398
1399 if (cc->cpu)
1400 free_percpu(cc->cpu);
1401
1402 kzfree(cc->cipher);
1403 kzfree(cc->cipher_string);
1404
1405 /* Must zero key material before freeing */
1406 kzfree(cc);
1407}
1408
1409static int crypt_ctr_cipher(struct dm_target *ti,
1410 char *cipher_in, char *key)
1411{
1412 struct crypt_config *cc = ti->private;
1413 char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount;
1414 char *cipher_api = NULL;
1415 int cpu, ret = -EINVAL;
1416
1417 /* Convert to crypto api definition? */
1418 if (strchr(cipher_in, '(')) {
1419 ti->error = "Bad cipher specification";
1420 return -EINVAL;
1421 }
1422
1423 cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
1424 if (!cc->cipher_string)
1425 goto bad_mem;
1426
1427 /*
1428 * Legacy dm-crypt cipher specification
1429 * cipher[:keycount]-mode-iv:ivopts
1430 */
1431 tmp = cipher_in;
1432 keycount = strsep(&tmp, "-");
1433 cipher = strsep(&keycount, ":");
1434
1435 if (!keycount)
1436 cc->tfms_count = 1;
1437 else if (sscanf(keycount, "%u", &cc->tfms_count) != 1 ||
1438 !is_power_of_2(cc->tfms_count)) {
1439 ti->error = "Bad cipher key count specification";
1440 return -EINVAL;
1441 }
1442 cc->key_parts = cc->tfms_count;
1443
1444 cc->cipher = kstrdup(cipher, GFP_KERNEL);
1445 if (!cc->cipher)
1446 goto bad_mem;
1447
1448 chainmode = strsep(&tmp, "-");
1449 ivopts = strsep(&tmp, "-");
1450 ivmode = strsep(&ivopts, ":");
1451
1452 if (tmp)
1453 DMWARN("Ignoring unexpected additional cipher options");
1454
1455 cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)) +
1456 cc->tfms_count * sizeof(*(cc->cpu->tfms)),
1457 __alignof__(struct crypt_cpu));
1458 if (!cc->cpu) {
1459 ti->error = "Cannot allocate per cpu state";
1460 goto bad_mem;
1461 }
1462
1463 /*
1464 * For compatibility with the original dm-crypt mapping format, if
1465 * only the cipher name is supplied, use cbc-plain.
1466 */
1467 if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
1468 chainmode = "cbc";
1469 ivmode = "plain";
1470 }
1471
1472 if (strcmp(chainmode, "ecb") && !ivmode) {
1473 ti->error = "IV mechanism required";
1474 return -EINVAL;
1475 }
1476
1477 cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
1478 if (!cipher_api)
1479 goto bad_mem;
1480
1481 ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
1482 "%s(%s)", chainmode, cipher);
1483 if (ret < 0) {
1484 kfree(cipher_api);
1485 goto bad_mem;
1486 }
1487
1488 /* Allocate cipher */
1489 for_each_possible_cpu(cpu) {
1490 ret = crypt_alloc_tfms(cc, cpu, cipher_api);
1491 if (ret < 0) {
1492 ti->error = "Error allocating crypto tfm";
1493 goto bad;
1494 }
1495 }
1496
1497 /* Initialize and set key */
1498 ret = crypt_set_key(cc, key);
1499 if (ret < 0) {
1500 ti->error = "Error decoding and setting key";
1501 goto bad;
1502 }
1503
1504 /* Initialize IV */
1505 cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc));
1506 if (cc->iv_size)
1507 /* at least a 64 bit sector number should fit in our buffer */
1508 cc->iv_size = max(cc->iv_size,
1509 (unsigned int)(sizeof(u64) / sizeof(u8)));
1510 else if (ivmode) {
1511 DMWARN("Selected cipher does not support IVs");
1512 ivmode = NULL;
1513 }
1514
1515 /* Choose ivmode, see comments at iv code. */
1516 if (ivmode == NULL)
1517 cc->iv_gen_ops = NULL;
1518 else if (strcmp(ivmode, "plain") == 0)
1519 cc->iv_gen_ops = &crypt_iv_plain_ops;
1520 else if (strcmp(ivmode, "plain64") == 0)
1521 cc->iv_gen_ops = &crypt_iv_plain64_ops;
1522 else if (strcmp(ivmode, "essiv") == 0)
1523 cc->iv_gen_ops = &crypt_iv_essiv_ops;
1524 else if (strcmp(ivmode, "benbi") == 0)
1525 cc->iv_gen_ops = &crypt_iv_benbi_ops;
1526 else if (strcmp(ivmode, "null") == 0)
1527 cc->iv_gen_ops = &crypt_iv_null_ops;
1528 else if (strcmp(ivmode, "lmk") == 0) {
1529 cc->iv_gen_ops = &crypt_iv_lmk_ops;
1530 /* Version 2 and 3 is recognised according
1531 * to length of provided multi-key string.
1532 * If present (version 3), last key is used as IV seed.
1533 */
1534 if (cc->key_size % cc->key_parts)
1535 cc->key_parts++;
1536 } else {
1537 ret = -EINVAL;
1538 ti->error = "Invalid IV mode";
1539 goto bad;
1540 }
1541
1542 /* Allocate IV */
1543 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
1544 ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
1545 if (ret < 0) {
1546 ti->error = "Error creating IV";
1547 goto bad;
1548 }
1549 }
1550
1551 /* Initialize IV (set keys for ESSIV etc) */
1552 if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
1553 ret = cc->iv_gen_ops->init(cc);
1554 if (ret < 0) {
1555 ti->error = "Error initialising IV";
1556 goto bad;
1557 }
1558 }
1559
1560 ret = 0;
1561bad:
1562 kfree(cipher_api);
1563 return ret;
1564
1565bad_mem:
1566 ti->error = "Cannot allocate cipher strings";
1567 return -ENOMEM;
1568}
1569
1570/*
1571 * Construct an encryption mapping:
1572 * <cipher> <key> <iv_offset> <dev_path> <start>
1573 */
1574static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1575{
1576 struct crypt_config *cc;
1577 unsigned int key_size, opt_params;
1578 unsigned long long tmpll;
1579 int ret;
1580 struct dm_arg_set as;
1581 const char *opt_string;
1582
1583 static struct dm_arg _args[] = {
1584 {0, 1, "Invalid number of feature args"},
1585 };
1586
1587 if (argc < 5) {
1588 ti->error = "Not enough arguments";
1589 return -EINVAL;
1590 }
1591
1592 key_size = strlen(argv[1]) >> 1;
1593
1594 cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
1595 if (!cc) {
1596 ti->error = "Cannot allocate encryption context";
1597 return -ENOMEM;
1598 }
1599 cc->key_size = key_size;
1600
1601 ti->private = cc;
1602 ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
1603 if (ret < 0)
1604 goto bad;
1605
1606 ret = -ENOMEM;
1607 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1608 if (!cc->io_pool) {
1609 ti->error = "Cannot allocate crypt io mempool";
1610 goto bad;
1611 }
1612
1613 cc->dmreq_start = sizeof(struct ablkcipher_request);
1614 cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc));
1615 cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
1616 cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) &
1617 ~(crypto_tfm_ctx_alignment() - 1);
1618
1619 cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1620 sizeof(struct dm_crypt_request) + cc->iv_size);
1621 if (!cc->req_pool) {
1622 ti->error = "Cannot allocate crypt request mempool";
1623 goto bad;
1624 }
1625
1626 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1627 if (!cc->page_pool) {
1628 ti->error = "Cannot allocate page mempool";
1629 goto bad;
1630 }
1631
1632 cc->bs = bioset_create(MIN_IOS, 0);
1633 if (!cc->bs) {
1634 ti->error = "Cannot allocate crypt bioset";
1635 goto bad;
1636 }
1637
1638 ret = -EINVAL;
1639 if (sscanf(argv[2], "%llu", &tmpll) != 1) {
1640 ti->error = "Invalid iv_offset sector";
1641 goto bad;
1642 }
1643 cc->iv_offset = tmpll;
1644
1645 if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
1646 ti->error = "Device lookup failed";
1647 goto bad;
1648 }
1649
1650 if (sscanf(argv[4], "%llu", &tmpll) != 1) {
1651 ti->error = "Invalid device sector";
1652 goto bad;
1653 }
1654 cc->start = tmpll;
1655
1656 argv += 5;
1657 argc -= 5;
1658
1659 /* Optional parameters */
1660 if (argc) {
1661 as.argc = argc;
1662 as.argv = argv;
1663
1664 ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1665 if (ret)
1666 goto bad;
1667
1668 opt_string = dm_shift_arg(&as);
1669
1670 if (opt_params == 1 && opt_string &&
1671 !strcasecmp(opt_string, "allow_discards"))
1672 ti->num_discard_requests = 1;
1673 else if (opt_params) {
1674 ret = -EINVAL;
1675 ti->error = "Invalid feature arguments";
1676 goto bad;
1677 }
1678 }
1679
1680 ret = -ENOMEM;
1681 cc->io_queue = alloc_workqueue("kcryptd_io",
1682 WQ_NON_REENTRANT|
1683 WQ_MEM_RECLAIM,
1684 1);
1685 if (!cc->io_queue) {
1686 ti->error = "Couldn't create kcryptd io queue";
1687 goto bad;
1688 }
1689
1690 cc->crypt_queue = alloc_workqueue("kcryptd",
1691 WQ_NON_REENTRANT|
1692 WQ_CPU_INTENSIVE|
1693 WQ_MEM_RECLAIM,
1694 1);
1695 if (!cc->crypt_queue) {
1696 ti->error = "Couldn't create kcryptd queue";
1697 goto bad;
1698 }
1699
1700 ti->num_flush_requests = 1;
1701 ti->discard_zeroes_data_unsupported = 1;
1702
1703 return 0;
1704
1705bad:
1706 crypt_dtr(ti);
1707 return ret;
1708}
1709
1710static int crypt_map(struct dm_target *ti, struct bio *bio,
1711 union map_info *map_context)
1712{
1713 struct dm_crypt_io *io;
1714 struct crypt_config *cc;
1715
1716 /*
1717 * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues.
1718 * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight
1719 * - for REQ_DISCARD caller must use flush if IO ordering matters
1720 */
1721 if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) {
1722 cc = ti->private;
1723 bio->bi_bdev = cc->dev->bdev;
1724 if (bio_sectors(bio))
1725 bio->bi_sector = cc->start + dm_target_offset(ti, bio->bi_sector);
1726 return DM_MAPIO_REMAPPED;
1727 }
1728
1729 io = crypt_io_alloc(ti, bio, dm_target_offset(ti, bio->bi_sector));
1730
1731 if (bio_data_dir(io->base_bio) == READ) {
1732 if (kcryptd_io_read(io, GFP_NOWAIT))
1733 kcryptd_queue_io(io);
1734 } else
1735 kcryptd_queue_crypt(io);
1736
1737 return DM_MAPIO_SUBMITTED;
1738}
1739
1740static int crypt_status(struct dm_target *ti, status_type_t type,
1741 char *result, unsigned int maxlen)
1742{
1743 struct crypt_config *cc = ti->private;
1744 unsigned int sz = 0;
1745
1746 switch (type) {
1747 case STATUSTYPE_INFO:
1748 result[0] = '\0';
1749 break;
1750
1751 case STATUSTYPE_TABLE:
1752 DMEMIT("%s ", cc->cipher_string);
1753
1754 if (cc->key_size > 0) {
1755 if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1756 return -ENOMEM;
1757
1758 crypt_encode_key(result + sz, cc->key, cc->key_size);
1759 sz += cc->key_size << 1;
1760 } else {
1761 if (sz >= maxlen)
1762 return -ENOMEM;
1763 result[sz++] = '-';
1764 }
1765
1766 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1767 cc->dev->name, (unsigned long long)cc->start);
1768
1769 if (ti->num_discard_requests)
1770 DMEMIT(" 1 allow_discards");
1771
1772 break;
1773 }
1774 return 0;
1775}
1776
1777static void crypt_postsuspend(struct dm_target *ti)
1778{
1779 struct crypt_config *cc = ti->private;
1780
1781 set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1782}
1783
1784static int crypt_preresume(struct dm_target *ti)
1785{
1786 struct crypt_config *cc = ti->private;
1787
1788 if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1789 DMERR("aborting resume - crypt key is not set.");
1790 return -EAGAIN;
1791 }
1792
1793 return 0;
1794}
1795
1796static void crypt_resume(struct dm_target *ti)
1797{
1798 struct crypt_config *cc = ti->private;
1799
1800 clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1801}
1802
1803/* Message interface
1804 * key set <key>
1805 * key wipe
1806 */
1807static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1808{
1809 struct crypt_config *cc = ti->private;
1810 int ret = -EINVAL;
1811
1812 if (argc < 2)
1813 goto error;
1814
1815 if (!strcasecmp(argv[0], "key")) {
1816 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1817 DMWARN("not suspended during key manipulation.");
1818 return -EINVAL;
1819 }
1820 if (argc == 3 && !strcasecmp(argv[1], "set")) {
1821 ret = crypt_set_key(cc, argv[2]);
1822 if (ret)
1823 return ret;
1824 if (cc->iv_gen_ops && cc->iv_gen_ops->init)
1825 ret = cc->iv_gen_ops->init(cc);
1826 return ret;
1827 }
1828 if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
1829 if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
1830 ret = cc->iv_gen_ops->wipe(cc);
1831 if (ret)
1832 return ret;
1833 }
1834 return crypt_wipe_key(cc);
1835 }
1836 }
1837
1838error:
1839 DMWARN("unrecognised message received.");
1840 return -EINVAL;
1841}
1842
1843static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1844 struct bio_vec *biovec, int max_size)
1845{
1846 struct crypt_config *cc = ti->private;
1847 struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1848
1849 if (!q->merge_bvec_fn)
1850 return max_size;
1851
1852 bvm->bi_bdev = cc->dev->bdev;
1853 bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
1854
1855 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1856}
1857
1858static int crypt_iterate_devices(struct dm_target *ti,
1859 iterate_devices_callout_fn fn, void *data)
1860{
1861 struct crypt_config *cc = ti->private;
1862
1863 return fn(ti, cc->dev, cc->start, ti->len, data);
1864}
1865
1866static struct target_type crypt_target = {
1867 .name = "crypt",
1868 .version = {1, 11, 0},
1869 .module = THIS_MODULE,
1870 .ctr = crypt_ctr,
1871 .dtr = crypt_dtr,
1872 .map = crypt_map,
1873 .status = crypt_status,
1874 .postsuspend = crypt_postsuspend,
1875 .preresume = crypt_preresume,
1876 .resume = crypt_resume,
1877 .message = crypt_message,
1878 .merge = crypt_merge,
1879 .iterate_devices = crypt_iterate_devices,
1880};
1881
1882static int __init dm_crypt_init(void)
1883{
1884 int r;
1885
1886 _crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1887 if (!_crypt_io_pool)
1888 return -ENOMEM;
1889
1890 r = dm_register_target(&crypt_target);
1891 if (r < 0) {
1892 DMERR("register failed %d", r);
1893 kmem_cache_destroy(_crypt_io_pool);
1894 }
1895
1896 return r;
1897}
1898
1899static void __exit dm_crypt_exit(void)
1900{
1901 dm_unregister_target(&crypt_target);
1902 kmem_cache_destroy(_crypt_io_pool);
1903}
1904
1905module_init(dm_crypt_init);
1906module_exit(dm_crypt_exit);
1907
1908MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1909MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1910MODULE_LICENSE("GPL");