xref: /linux/drivers/md/dm-crypt.c (revision dc0d1c4519095a6c6bbd9ec4a808674aba502741)
1 /*
2  * Copyright (C) 2003 Jana Saout <jana@saout.de>
3  * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
4  * Copyright (C) 2006-2017 Red Hat, Inc. All rights reserved.
5  * Copyright (C) 2013-2017 Milan Broz <gmazyland@gmail.com>
6  *
7  * This file is released under the GPL.
8  */
9 
10 #include <linux/completion.h>
11 #include <linux/err.h>
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/key.h>
16 #include <linux/bio.h>
17 #include <linux/blkdev.h>
18 #include <linux/mempool.h>
19 #include <linux/slab.h>
20 #include <linux/crypto.h>
21 #include <linux/workqueue.h>
22 #include <linux/kthread.h>
23 #include <linux/backing-dev.h>
24 #include <linux/atomic.h>
25 #include <linux/scatterlist.h>
26 #include <linux/rbtree.h>
27 #include <linux/ctype.h>
28 #include <asm/page.h>
29 #include <asm/unaligned.h>
30 #include <crypto/hash.h>
31 #include <crypto/md5.h>
32 #include <crypto/algapi.h>
33 #include <crypto/skcipher.h>
34 #include <crypto/aead.h>
35 #include <crypto/authenc.h>
36 #include <linux/rtnetlink.h> /* for struct rtattr and RTA macros only */
37 #include <keys/user-type.h>
38 
39 #include <linux/device-mapper.h>
40 
41 #define DM_MSG_PREFIX "crypt"
42 
43 /*
44  * context holding the current state of a multi-part conversion
45  */
46 struct convert_context {
47 	struct completion restart;
48 	struct bio *bio_in;
49 	struct bio *bio_out;
50 	struct bvec_iter iter_in;
51 	struct bvec_iter iter_out;
52 	sector_t cc_sector;
53 	atomic_t cc_pending;
54 	union {
55 		struct skcipher_request *req;
56 		struct aead_request *req_aead;
57 	} r;
58 
59 };
60 
61 /*
62  * per bio private data
63  */
64 struct dm_crypt_io {
65 	struct crypt_config *cc;
66 	struct bio *base_bio;
67 	u8 *integrity_metadata;
68 	bool integrity_metadata_from_pool;
69 	struct work_struct work;
70 
71 	struct convert_context ctx;
72 
73 	atomic_t io_pending;
74 	blk_status_t error;
75 	sector_t sector;
76 
77 	struct rb_node rb_node;
78 } CRYPTO_MINALIGN_ATTR;
79 
80 struct dm_crypt_request {
81 	struct convert_context *ctx;
82 	struct scatterlist sg_in[4];
83 	struct scatterlist sg_out[4];
84 	sector_t iv_sector;
85 };
86 
87 struct crypt_config;
88 
89 struct crypt_iv_operations {
90 	int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
91 		   const char *opts);
92 	void (*dtr)(struct crypt_config *cc);
93 	int (*init)(struct crypt_config *cc);
94 	int (*wipe)(struct crypt_config *cc);
95 	int (*generator)(struct crypt_config *cc, u8 *iv,
96 			 struct dm_crypt_request *dmreq);
97 	int (*post)(struct crypt_config *cc, u8 *iv,
98 		    struct dm_crypt_request *dmreq);
99 };
100 
101 struct iv_essiv_private {
102 	struct crypto_shash *hash_tfm;
103 	u8 *salt;
104 };
105 
106 struct iv_benbi_private {
107 	int shift;
108 };
109 
110 #define LMK_SEED_SIZE 64 /* hash + 0 */
111 struct iv_lmk_private {
112 	struct crypto_shash *hash_tfm;
113 	u8 *seed;
114 };
115 
116 #define TCW_WHITENING_SIZE 16
117 struct iv_tcw_private {
118 	struct crypto_shash *crc32_tfm;
119 	u8 *iv_seed;
120 	u8 *whitening;
121 };
122 
123 /*
124  * Crypt: maps a linear range of a block device
125  * and encrypts / decrypts at the same time.
126  */
127 enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID,
128 	     DM_CRYPT_SAME_CPU, DM_CRYPT_NO_OFFLOAD };
129 
130 enum cipher_flags {
131 	CRYPT_MODE_INTEGRITY_AEAD,	/* Use authenticated mode for cihper */
132 	CRYPT_IV_LARGE_SECTORS,		/* Calculate IV from sector_size, not 512B sectors */
133 };
134 
135 /*
136  * The fields in here must be read only after initialization.
137  */
138 struct crypt_config {
139 	struct dm_dev *dev;
140 	sector_t start;
141 
142 	struct percpu_counter n_allocated_pages;
143 
144 	struct workqueue_struct *io_queue;
145 	struct workqueue_struct *crypt_queue;
146 
147 	spinlock_t write_thread_lock;
148 	struct task_struct *write_thread;
149 	struct rb_root write_tree;
150 
151 	char *cipher;
152 	char *cipher_string;
153 	char *cipher_auth;
154 	char *key_string;
155 
156 	const struct crypt_iv_operations *iv_gen_ops;
157 	union {
158 		struct iv_essiv_private essiv;
159 		struct iv_benbi_private benbi;
160 		struct iv_lmk_private lmk;
161 		struct iv_tcw_private tcw;
162 	} iv_gen_private;
163 	sector_t iv_offset;
164 	unsigned int iv_size;
165 	unsigned short int sector_size;
166 	unsigned char sector_shift;
167 
168 	/* ESSIV: struct crypto_cipher *essiv_tfm */
169 	void *iv_private;
170 	union {
171 		struct crypto_skcipher **tfms;
172 		struct crypto_aead **tfms_aead;
173 	} cipher_tfm;
174 	unsigned tfms_count;
175 	unsigned long cipher_flags;
176 
177 	/*
178 	 * Layout of each crypto request:
179 	 *
180 	 *   struct skcipher_request
181 	 *      context
182 	 *      padding
183 	 *   struct dm_crypt_request
184 	 *      padding
185 	 *   IV
186 	 *
187 	 * The padding is added so that dm_crypt_request and the IV are
188 	 * correctly aligned.
189 	 */
190 	unsigned int dmreq_start;
191 
192 	unsigned int per_bio_data_size;
193 
194 	unsigned long flags;
195 	unsigned int key_size;
196 	unsigned int key_parts;      /* independent parts in key buffer */
197 	unsigned int key_extra_size; /* additional keys length */
198 	unsigned int key_mac_size;   /* MAC key size for authenc(...) */
199 
200 	unsigned int integrity_tag_size;
201 	unsigned int integrity_iv_size;
202 	unsigned int on_disk_tag_size;
203 
204 	/*
205 	 * pool for per bio private data, crypto requests,
206 	 * encryption requeusts/buffer pages and integrity tags
207 	 */
208 	unsigned tag_pool_max_sectors;
209 	mempool_t tag_pool;
210 	mempool_t req_pool;
211 	mempool_t page_pool;
212 
213 	struct bio_set bs;
214 	struct mutex bio_alloc_lock;
215 
216 	u8 *authenc_key; /* space for keys in authenc() format (if used) */
217 	u8 key[0];
218 };
219 
220 #define MIN_IOS		64
221 #define MAX_TAG_SIZE	480
222 #define POOL_ENTRY_SIZE	512
223 
224 static DEFINE_SPINLOCK(dm_crypt_clients_lock);
225 static unsigned dm_crypt_clients_n = 0;
226 static volatile unsigned long dm_crypt_pages_per_client;
227 #define DM_CRYPT_MEMORY_PERCENT			2
228 #define DM_CRYPT_MIN_PAGES_PER_CLIENT		(BIO_MAX_PAGES * 16)
229 
230 static void clone_init(struct dm_crypt_io *, struct bio *);
231 static void kcryptd_queue_crypt(struct dm_crypt_io *io);
232 static struct scatterlist *crypt_get_sg_data(struct crypt_config *cc,
233 					     struct scatterlist *sg);
234 
235 /*
236  * Use this to access cipher attributes that are independent of the key.
237  */
238 static struct crypto_skcipher *any_tfm(struct crypt_config *cc)
239 {
240 	return cc->cipher_tfm.tfms[0];
241 }
242 
243 static struct crypto_aead *any_tfm_aead(struct crypt_config *cc)
244 {
245 	return cc->cipher_tfm.tfms_aead[0];
246 }
247 
248 /*
249  * Different IV generation algorithms:
250  *
251  * plain: the initial vector is the 32-bit little-endian version of the sector
252  *        number, padded with zeros if necessary.
253  *
254  * plain64: the initial vector is the 64-bit little-endian version of the sector
255  *        number, padded with zeros if necessary.
256  *
257  * plain64be: the initial vector is the 64-bit big-endian version of the sector
258  *        number, padded with zeros if necessary.
259  *
260  * essiv: "encrypted sector|salt initial vector", the sector number is
261  *        encrypted with the bulk cipher using a salt as key. The salt
262  *        should be derived from the bulk cipher's key via hashing.
263  *
264  * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
265  *        (needed for LRW-32-AES and possible other narrow block modes)
266  *
267  * null: the initial vector is always zero.  Provides compatibility with
268  *       obsolete loop_fish2 devices.  Do not use for new devices.
269  *
270  * lmk:  Compatible implementation of the block chaining mode used
271  *       by the Loop-AES block device encryption system
272  *       designed by Jari Ruusu. See http://loop-aes.sourceforge.net/
273  *       It operates on full 512 byte sectors and uses CBC
274  *       with an IV derived from the sector number, the data and
275  *       optionally extra IV seed.
276  *       This means that after decryption the first block
277  *       of sector must be tweaked according to decrypted data.
278  *       Loop-AES can use three encryption schemes:
279  *         version 1: is plain aes-cbc mode
280  *         version 2: uses 64 multikey scheme with lmk IV generator
281  *         version 3: the same as version 2 with additional IV seed
282  *                   (it uses 65 keys, last key is used as IV seed)
283  *
284  * tcw:  Compatible implementation of the block chaining mode used
285  *       by the TrueCrypt device encryption system (prior to version 4.1).
286  *       For more info see: https://gitlab.com/cryptsetup/cryptsetup/wikis/TrueCryptOnDiskFormat
287  *       It operates on full 512 byte sectors and uses CBC
288  *       with an IV derived from initial key and the sector number.
289  *       In addition, whitening value is applied on every sector, whitening
290  *       is calculated from initial key, sector number and mixed using CRC32.
291  *       Note that this encryption scheme is vulnerable to watermarking attacks
292  *       and should be used for old compatible containers access only.
293  *
294  * plumb: unimplemented, see:
295  * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
296  */
297 
298 static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv,
299 			      struct dm_crypt_request *dmreq)
300 {
301 	memset(iv, 0, cc->iv_size);
302 	*(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff);
303 
304 	return 0;
305 }
306 
307 static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
308 				struct dm_crypt_request *dmreq)
309 {
310 	memset(iv, 0, cc->iv_size);
311 	*(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
312 
313 	return 0;
314 }
315 
316 static int crypt_iv_plain64be_gen(struct crypt_config *cc, u8 *iv,
317 				  struct dm_crypt_request *dmreq)
318 {
319 	memset(iv, 0, cc->iv_size);
320 	/* iv_size is at least of size u64; usually it is 16 bytes */
321 	*(__be64 *)&iv[cc->iv_size - sizeof(u64)] = cpu_to_be64(dmreq->iv_sector);
322 
323 	return 0;
324 }
325 
326 /* Initialise ESSIV - compute salt but no local memory allocations */
327 static int crypt_iv_essiv_init(struct crypt_config *cc)
328 {
329 	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
330 	SHASH_DESC_ON_STACK(desc, essiv->hash_tfm);
331 	struct crypto_cipher *essiv_tfm;
332 	int err;
333 
334 	desc->tfm = essiv->hash_tfm;
335 	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
336 
337 	err = crypto_shash_digest(desc, cc->key, cc->key_size, essiv->salt);
338 	shash_desc_zero(desc);
339 	if (err)
340 		return err;
341 
342 	essiv_tfm = cc->iv_private;
343 
344 	err = crypto_cipher_setkey(essiv_tfm, essiv->salt,
345 			    crypto_shash_digestsize(essiv->hash_tfm));
346 	if (err)
347 		return err;
348 
349 	return 0;
350 }
351 
352 /* Wipe salt and reset key derived from volume key */
353 static int crypt_iv_essiv_wipe(struct crypt_config *cc)
354 {
355 	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
356 	unsigned salt_size = crypto_shash_digestsize(essiv->hash_tfm);
357 	struct crypto_cipher *essiv_tfm;
358 	int r, err = 0;
359 
360 	memset(essiv->salt, 0, salt_size);
361 
362 	essiv_tfm = cc->iv_private;
363 	r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size);
364 	if (r)
365 		err = r;
366 
367 	return err;
368 }
369 
370 /* Allocate the cipher for ESSIV */
371 static struct crypto_cipher *alloc_essiv_cipher(struct crypt_config *cc,
372 						struct dm_target *ti,
373 						const u8 *salt,
374 						unsigned int saltsize)
375 {
376 	struct crypto_cipher *essiv_tfm;
377 	int err;
378 
379 	/* Setup the essiv_tfm with the given salt */
380 	essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
381 	if (IS_ERR(essiv_tfm)) {
382 		ti->error = "Error allocating crypto tfm for ESSIV";
383 		return essiv_tfm;
384 	}
385 
386 	if (crypto_cipher_blocksize(essiv_tfm) != cc->iv_size) {
387 		ti->error = "Block size of ESSIV cipher does "
388 			    "not match IV size of block cipher";
389 		crypto_free_cipher(essiv_tfm);
390 		return ERR_PTR(-EINVAL);
391 	}
392 
393 	err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
394 	if (err) {
395 		ti->error = "Failed to set key for ESSIV cipher";
396 		crypto_free_cipher(essiv_tfm);
397 		return ERR_PTR(err);
398 	}
399 
400 	return essiv_tfm;
401 }
402 
403 static void crypt_iv_essiv_dtr(struct crypt_config *cc)
404 {
405 	struct crypto_cipher *essiv_tfm;
406 	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
407 
408 	crypto_free_shash(essiv->hash_tfm);
409 	essiv->hash_tfm = NULL;
410 
411 	kzfree(essiv->salt);
412 	essiv->salt = NULL;
413 
414 	essiv_tfm = cc->iv_private;
415 
416 	if (essiv_tfm)
417 		crypto_free_cipher(essiv_tfm);
418 
419 	cc->iv_private = NULL;
420 }
421 
422 static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
423 			      const char *opts)
424 {
425 	struct crypto_cipher *essiv_tfm = NULL;
426 	struct crypto_shash *hash_tfm = NULL;
427 	u8 *salt = NULL;
428 	int err;
429 
430 	if (!opts) {
431 		ti->error = "Digest algorithm missing for ESSIV mode";
432 		return -EINVAL;
433 	}
434 
435 	/* Allocate hash algorithm */
436 	hash_tfm = crypto_alloc_shash(opts, 0, 0);
437 	if (IS_ERR(hash_tfm)) {
438 		ti->error = "Error initializing ESSIV hash";
439 		err = PTR_ERR(hash_tfm);
440 		goto bad;
441 	}
442 
443 	salt = kzalloc(crypto_shash_digestsize(hash_tfm), GFP_KERNEL);
444 	if (!salt) {
445 		ti->error = "Error kmallocing salt storage in ESSIV";
446 		err = -ENOMEM;
447 		goto bad;
448 	}
449 
450 	cc->iv_gen_private.essiv.salt = salt;
451 	cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
452 
453 	essiv_tfm = alloc_essiv_cipher(cc, ti, salt,
454 				       crypto_shash_digestsize(hash_tfm));
455 	if (IS_ERR(essiv_tfm)) {
456 		crypt_iv_essiv_dtr(cc);
457 		return PTR_ERR(essiv_tfm);
458 	}
459 	cc->iv_private = essiv_tfm;
460 
461 	return 0;
462 
463 bad:
464 	if (hash_tfm && !IS_ERR(hash_tfm))
465 		crypto_free_shash(hash_tfm);
466 	kfree(salt);
467 	return err;
468 }
469 
470 static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv,
471 			      struct dm_crypt_request *dmreq)
472 {
473 	struct crypto_cipher *essiv_tfm = cc->iv_private;
474 
475 	memset(iv, 0, cc->iv_size);
476 	*(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
477 	crypto_cipher_encrypt_one(essiv_tfm, iv, iv);
478 
479 	return 0;
480 }
481 
482 static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
483 			      const char *opts)
484 {
485 	unsigned bs = crypto_skcipher_blocksize(any_tfm(cc));
486 	int log = ilog2(bs);
487 
488 	/* we need to calculate how far we must shift the sector count
489 	 * to get the cipher block count, we use this shift in _gen */
490 
491 	if (1 << log != bs) {
492 		ti->error = "cypher blocksize is not a power of 2";
493 		return -EINVAL;
494 	}
495 
496 	if (log > 9) {
497 		ti->error = "cypher blocksize is > 512";
498 		return -EINVAL;
499 	}
500 
501 	cc->iv_gen_private.benbi.shift = 9 - log;
502 
503 	return 0;
504 }
505 
506 static void crypt_iv_benbi_dtr(struct crypt_config *cc)
507 {
508 }
509 
510 static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv,
511 			      struct dm_crypt_request *dmreq)
512 {
513 	__be64 val;
514 
515 	memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
516 
517 	val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1);
518 	put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
519 
520 	return 0;
521 }
522 
523 static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv,
524 			     struct dm_crypt_request *dmreq)
525 {
526 	memset(iv, 0, cc->iv_size);
527 
528 	return 0;
529 }
530 
531 static void crypt_iv_lmk_dtr(struct crypt_config *cc)
532 {
533 	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
534 
535 	if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm))
536 		crypto_free_shash(lmk->hash_tfm);
537 	lmk->hash_tfm = NULL;
538 
539 	kzfree(lmk->seed);
540 	lmk->seed = NULL;
541 }
542 
543 static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti,
544 			    const char *opts)
545 {
546 	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
547 
548 	if (cc->sector_size != (1 << SECTOR_SHIFT)) {
549 		ti->error = "Unsupported sector size for LMK";
550 		return -EINVAL;
551 	}
552 
553 	lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0);
554 	if (IS_ERR(lmk->hash_tfm)) {
555 		ti->error = "Error initializing LMK hash";
556 		return PTR_ERR(lmk->hash_tfm);
557 	}
558 
559 	/* No seed in LMK version 2 */
560 	if (cc->key_parts == cc->tfms_count) {
561 		lmk->seed = NULL;
562 		return 0;
563 	}
564 
565 	lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL);
566 	if (!lmk->seed) {
567 		crypt_iv_lmk_dtr(cc);
568 		ti->error = "Error kmallocing seed storage in LMK";
569 		return -ENOMEM;
570 	}
571 
572 	return 0;
573 }
574 
575 static int crypt_iv_lmk_init(struct crypt_config *cc)
576 {
577 	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
578 	int subkey_size = cc->key_size / cc->key_parts;
579 
580 	/* LMK seed is on the position of LMK_KEYS + 1 key */
581 	if (lmk->seed)
582 		memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size),
583 		       crypto_shash_digestsize(lmk->hash_tfm));
584 
585 	return 0;
586 }
587 
588 static int crypt_iv_lmk_wipe(struct crypt_config *cc)
589 {
590 	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
591 
592 	if (lmk->seed)
593 		memset(lmk->seed, 0, LMK_SEED_SIZE);
594 
595 	return 0;
596 }
597 
598 static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv,
599 			    struct dm_crypt_request *dmreq,
600 			    u8 *data)
601 {
602 	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
603 	SHASH_DESC_ON_STACK(desc, lmk->hash_tfm);
604 	struct md5_state md5state;
605 	__le32 buf[4];
606 	int i, r;
607 
608 	desc->tfm = lmk->hash_tfm;
609 	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
610 
611 	r = crypto_shash_init(desc);
612 	if (r)
613 		return r;
614 
615 	if (lmk->seed) {
616 		r = crypto_shash_update(desc, lmk->seed, LMK_SEED_SIZE);
617 		if (r)
618 			return r;
619 	}
620 
621 	/* Sector is always 512B, block size 16, add data of blocks 1-31 */
622 	r = crypto_shash_update(desc, data + 16, 16 * 31);
623 	if (r)
624 		return r;
625 
626 	/* Sector is cropped to 56 bits here */
627 	buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF);
628 	buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000);
629 	buf[2] = cpu_to_le32(4024);
630 	buf[3] = 0;
631 	r = crypto_shash_update(desc, (u8 *)buf, sizeof(buf));
632 	if (r)
633 		return r;
634 
635 	/* No MD5 padding here */
636 	r = crypto_shash_export(desc, &md5state);
637 	if (r)
638 		return r;
639 
640 	for (i = 0; i < MD5_HASH_WORDS; i++)
641 		__cpu_to_le32s(&md5state.hash[i]);
642 	memcpy(iv, &md5state.hash, cc->iv_size);
643 
644 	return 0;
645 }
646 
647 static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv,
648 			    struct dm_crypt_request *dmreq)
649 {
650 	struct scatterlist *sg;
651 	u8 *src;
652 	int r = 0;
653 
654 	if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) {
655 		sg = crypt_get_sg_data(cc, dmreq->sg_in);
656 		src = kmap_atomic(sg_page(sg));
657 		r = crypt_iv_lmk_one(cc, iv, dmreq, src + sg->offset);
658 		kunmap_atomic(src);
659 	} else
660 		memset(iv, 0, cc->iv_size);
661 
662 	return r;
663 }
664 
665 static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv,
666 			     struct dm_crypt_request *dmreq)
667 {
668 	struct scatterlist *sg;
669 	u8 *dst;
670 	int r;
671 
672 	if (bio_data_dir(dmreq->ctx->bio_in) == WRITE)
673 		return 0;
674 
675 	sg = crypt_get_sg_data(cc, dmreq->sg_out);
676 	dst = kmap_atomic(sg_page(sg));
677 	r = crypt_iv_lmk_one(cc, iv, dmreq, dst + sg->offset);
678 
679 	/* Tweak the first block of plaintext sector */
680 	if (!r)
681 		crypto_xor(dst + sg->offset, iv, cc->iv_size);
682 
683 	kunmap_atomic(dst);
684 	return r;
685 }
686 
687 static void crypt_iv_tcw_dtr(struct crypt_config *cc)
688 {
689 	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
690 
691 	kzfree(tcw->iv_seed);
692 	tcw->iv_seed = NULL;
693 	kzfree(tcw->whitening);
694 	tcw->whitening = NULL;
695 
696 	if (tcw->crc32_tfm && !IS_ERR(tcw->crc32_tfm))
697 		crypto_free_shash(tcw->crc32_tfm);
698 	tcw->crc32_tfm = NULL;
699 }
700 
701 static int crypt_iv_tcw_ctr(struct crypt_config *cc, struct dm_target *ti,
702 			    const char *opts)
703 {
704 	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
705 
706 	if (cc->sector_size != (1 << SECTOR_SHIFT)) {
707 		ti->error = "Unsupported sector size for TCW";
708 		return -EINVAL;
709 	}
710 
711 	if (cc->key_size <= (cc->iv_size + TCW_WHITENING_SIZE)) {
712 		ti->error = "Wrong key size for TCW";
713 		return -EINVAL;
714 	}
715 
716 	tcw->crc32_tfm = crypto_alloc_shash("crc32", 0, 0);
717 	if (IS_ERR(tcw->crc32_tfm)) {
718 		ti->error = "Error initializing CRC32 in TCW";
719 		return PTR_ERR(tcw->crc32_tfm);
720 	}
721 
722 	tcw->iv_seed = kzalloc(cc->iv_size, GFP_KERNEL);
723 	tcw->whitening = kzalloc(TCW_WHITENING_SIZE, GFP_KERNEL);
724 	if (!tcw->iv_seed || !tcw->whitening) {
725 		crypt_iv_tcw_dtr(cc);
726 		ti->error = "Error allocating seed storage in TCW";
727 		return -ENOMEM;
728 	}
729 
730 	return 0;
731 }
732 
733 static int crypt_iv_tcw_init(struct crypt_config *cc)
734 {
735 	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
736 	int key_offset = cc->key_size - cc->iv_size - TCW_WHITENING_SIZE;
737 
738 	memcpy(tcw->iv_seed, &cc->key[key_offset], cc->iv_size);
739 	memcpy(tcw->whitening, &cc->key[key_offset + cc->iv_size],
740 	       TCW_WHITENING_SIZE);
741 
742 	return 0;
743 }
744 
745 static int crypt_iv_tcw_wipe(struct crypt_config *cc)
746 {
747 	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
748 
749 	memset(tcw->iv_seed, 0, cc->iv_size);
750 	memset(tcw->whitening, 0, TCW_WHITENING_SIZE);
751 
752 	return 0;
753 }
754 
755 static int crypt_iv_tcw_whitening(struct crypt_config *cc,
756 				  struct dm_crypt_request *dmreq,
757 				  u8 *data)
758 {
759 	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
760 	__le64 sector = cpu_to_le64(dmreq->iv_sector);
761 	u8 buf[TCW_WHITENING_SIZE];
762 	SHASH_DESC_ON_STACK(desc, tcw->crc32_tfm);
763 	int i, r;
764 
765 	/* xor whitening with sector number */
766 	crypto_xor_cpy(buf, tcw->whitening, (u8 *)&sector, 8);
767 	crypto_xor_cpy(&buf[8], tcw->whitening + 8, (u8 *)&sector, 8);
768 
769 	/* calculate crc32 for every 32bit part and xor it */
770 	desc->tfm = tcw->crc32_tfm;
771 	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
772 	for (i = 0; i < 4; i++) {
773 		r = crypto_shash_init(desc);
774 		if (r)
775 			goto out;
776 		r = crypto_shash_update(desc, &buf[i * 4], 4);
777 		if (r)
778 			goto out;
779 		r = crypto_shash_final(desc, &buf[i * 4]);
780 		if (r)
781 			goto out;
782 	}
783 	crypto_xor(&buf[0], &buf[12], 4);
784 	crypto_xor(&buf[4], &buf[8], 4);
785 
786 	/* apply whitening (8 bytes) to whole sector */
787 	for (i = 0; i < ((1 << SECTOR_SHIFT) / 8); i++)
788 		crypto_xor(data + i * 8, buf, 8);
789 out:
790 	memzero_explicit(buf, sizeof(buf));
791 	return r;
792 }
793 
794 static int crypt_iv_tcw_gen(struct crypt_config *cc, u8 *iv,
795 			    struct dm_crypt_request *dmreq)
796 {
797 	struct scatterlist *sg;
798 	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
799 	__le64 sector = cpu_to_le64(dmreq->iv_sector);
800 	u8 *src;
801 	int r = 0;
802 
803 	/* Remove whitening from ciphertext */
804 	if (bio_data_dir(dmreq->ctx->bio_in) != WRITE) {
805 		sg = crypt_get_sg_data(cc, dmreq->sg_in);
806 		src = kmap_atomic(sg_page(sg));
807 		r = crypt_iv_tcw_whitening(cc, dmreq, src + sg->offset);
808 		kunmap_atomic(src);
809 	}
810 
811 	/* Calculate IV */
812 	crypto_xor_cpy(iv, tcw->iv_seed, (u8 *)&sector, 8);
813 	if (cc->iv_size > 8)
814 		crypto_xor_cpy(&iv[8], tcw->iv_seed + 8, (u8 *)&sector,
815 			       cc->iv_size - 8);
816 
817 	return r;
818 }
819 
820 static int crypt_iv_tcw_post(struct crypt_config *cc, u8 *iv,
821 			     struct dm_crypt_request *dmreq)
822 {
823 	struct scatterlist *sg;
824 	u8 *dst;
825 	int r;
826 
827 	if (bio_data_dir(dmreq->ctx->bio_in) != WRITE)
828 		return 0;
829 
830 	/* Apply whitening on ciphertext */
831 	sg = crypt_get_sg_data(cc, dmreq->sg_out);
832 	dst = kmap_atomic(sg_page(sg));
833 	r = crypt_iv_tcw_whitening(cc, dmreq, dst + sg->offset);
834 	kunmap_atomic(dst);
835 
836 	return r;
837 }
838 
839 static int crypt_iv_random_gen(struct crypt_config *cc, u8 *iv,
840 				struct dm_crypt_request *dmreq)
841 {
842 	/* Used only for writes, there must be an additional space to store IV */
843 	get_random_bytes(iv, cc->iv_size);
844 	return 0;
845 }
846 
847 static const struct crypt_iv_operations crypt_iv_plain_ops = {
848 	.generator = crypt_iv_plain_gen
849 };
850 
851 static const struct crypt_iv_operations crypt_iv_plain64_ops = {
852 	.generator = crypt_iv_plain64_gen
853 };
854 
855 static const struct crypt_iv_operations crypt_iv_plain64be_ops = {
856 	.generator = crypt_iv_plain64be_gen
857 };
858 
859 static const struct crypt_iv_operations crypt_iv_essiv_ops = {
860 	.ctr       = crypt_iv_essiv_ctr,
861 	.dtr       = crypt_iv_essiv_dtr,
862 	.init      = crypt_iv_essiv_init,
863 	.wipe      = crypt_iv_essiv_wipe,
864 	.generator = crypt_iv_essiv_gen
865 };
866 
867 static const struct crypt_iv_operations crypt_iv_benbi_ops = {
868 	.ctr	   = crypt_iv_benbi_ctr,
869 	.dtr	   = crypt_iv_benbi_dtr,
870 	.generator = crypt_iv_benbi_gen
871 };
872 
873 static const struct crypt_iv_operations crypt_iv_null_ops = {
874 	.generator = crypt_iv_null_gen
875 };
876 
877 static const struct crypt_iv_operations crypt_iv_lmk_ops = {
878 	.ctr	   = crypt_iv_lmk_ctr,
879 	.dtr	   = crypt_iv_lmk_dtr,
880 	.init	   = crypt_iv_lmk_init,
881 	.wipe	   = crypt_iv_lmk_wipe,
882 	.generator = crypt_iv_lmk_gen,
883 	.post	   = crypt_iv_lmk_post
884 };
885 
886 static const struct crypt_iv_operations crypt_iv_tcw_ops = {
887 	.ctr	   = crypt_iv_tcw_ctr,
888 	.dtr	   = crypt_iv_tcw_dtr,
889 	.init	   = crypt_iv_tcw_init,
890 	.wipe	   = crypt_iv_tcw_wipe,
891 	.generator = crypt_iv_tcw_gen,
892 	.post	   = crypt_iv_tcw_post
893 };
894 
895 static struct crypt_iv_operations crypt_iv_random_ops = {
896 	.generator = crypt_iv_random_gen
897 };
898 
899 /*
900  * Integrity extensions
901  */
902 static bool crypt_integrity_aead(struct crypt_config *cc)
903 {
904 	return test_bit(CRYPT_MODE_INTEGRITY_AEAD, &cc->cipher_flags);
905 }
906 
907 static bool crypt_integrity_hmac(struct crypt_config *cc)
908 {
909 	return crypt_integrity_aead(cc) && cc->key_mac_size;
910 }
911 
912 /* Get sg containing data */
913 static struct scatterlist *crypt_get_sg_data(struct crypt_config *cc,
914 					     struct scatterlist *sg)
915 {
916 	if (unlikely(crypt_integrity_aead(cc)))
917 		return &sg[2];
918 
919 	return sg;
920 }
921 
922 static int dm_crypt_integrity_io_alloc(struct dm_crypt_io *io, struct bio *bio)
923 {
924 	struct bio_integrity_payload *bip;
925 	unsigned int tag_len;
926 	int ret;
927 
928 	if (!bio_sectors(bio) || !io->cc->on_disk_tag_size)
929 		return 0;
930 
931 	bip = bio_integrity_alloc(bio, GFP_NOIO, 1);
932 	if (IS_ERR(bip))
933 		return PTR_ERR(bip);
934 
935 	tag_len = io->cc->on_disk_tag_size * bio_sectors(bio);
936 
937 	bip->bip_iter.bi_size = tag_len;
938 	bip->bip_iter.bi_sector = io->cc->start + io->sector;
939 
940 	ret = bio_integrity_add_page(bio, virt_to_page(io->integrity_metadata),
941 				     tag_len, offset_in_page(io->integrity_metadata));
942 	if (unlikely(ret != tag_len))
943 		return -ENOMEM;
944 
945 	return 0;
946 }
947 
948 static int crypt_integrity_ctr(struct crypt_config *cc, struct dm_target *ti)
949 {
950 #ifdef CONFIG_BLK_DEV_INTEGRITY
951 	struct blk_integrity *bi = blk_get_integrity(cc->dev->bdev->bd_disk);
952 
953 	/* From now we require underlying device with our integrity profile */
954 	if (!bi || strcasecmp(bi->profile->name, "DM-DIF-EXT-TAG")) {
955 		ti->error = "Integrity profile not supported.";
956 		return -EINVAL;
957 	}
958 
959 	if (bi->tag_size != cc->on_disk_tag_size ||
960 	    bi->tuple_size != cc->on_disk_tag_size) {
961 		ti->error = "Integrity profile tag size mismatch.";
962 		return -EINVAL;
963 	}
964 	if (1 << bi->interval_exp != cc->sector_size) {
965 		ti->error = "Integrity profile sector size mismatch.";
966 		return -EINVAL;
967 	}
968 
969 	if (crypt_integrity_aead(cc)) {
970 		cc->integrity_tag_size = cc->on_disk_tag_size - cc->integrity_iv_size;
971 		DMINFO("Integrity AEAD, tag size %u, IV size %u.",
972 		       cc->integrity_tag_size, cc->integrity_iv_size);
973 
974 		if (crypto_aead_setauthsize(any_tfm_aead(cc), cc->integrity_tag_size)) {
975 			ti->error = "Integrity AEAD auth tag size is not supported.";
976 			return -EINVAL;
977 		}
978 	} else if (cc->integrity_iv_size)
979 		DMINFO("Additional per-sector space %u bytes for IV.",
980 		       cc->integrity_iv_size);
981 
982 	if ((cc->integrity_tag_size + cc->integrity_iv_size) != bi->tag_size) {
983 		ti->error = "Not enough space for integrity tag in the profile.";
984 		return -EINVAL;
985 	}
986 
987 	return 0;
988 #else
989 	ti->error = "Integrity profile not supported.";
990 	return -EINVAL;
991 #endif
992 }
993 
994 static void crypt_convert_init(struct crypt_config *cc,
995 			       struct convert_context *ctx,
996 			       struct bio *bio_out, struct bio *bio_in,
997 			       sector_t sector)
998 {
999 	ctx->bio_in = bio_in;
1000 	ctx->bio_out = bio_out;
1001 	if (bio_in)
1002 		ctx->iter_in = bio_in->bi_iter;
1003 	if (bio_out)
1004 		ctx->iter_out = bio_out->bi_iter;
1005 	ctx->cc_sector = sector + cc->iv_offset;
1006 	init_completion(&ctx->restart);
1007 }
1008 
1009 static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
1010 					     void *req)
1011 {
1012 	return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
1013 }
1014 
1015 static void *req_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq)
1016 {
1017 	return (void *)((char *)dmreq - cc->dmreq_start);
1018 }
1019 
1020 static u8 *iv_of_dmreq(struct crypt_config *cc,
1021 		       struct dm_crypt_request *dmreq)
1022 {
1023 	if (crypt_integrity_aead(cc))
1024 		return (u8 *)ALIGN((unsigned long)(dmreq + 1),
1025 			crypto_aead_alignmask(any_tfm_aead(cc)) + 1);
1026 	else
1027 		return (u8 *)ALIGN((unsigned long)(dmreq + 1),
1028 			crypto_skcipher_alignmask(any_tfm(cc)) + 1);
1029 }
1030 
1031 static u8 *org_iv_of_dmreq(struct crypt_config *cc,
1032 		       struct dm_crypt_request *dmreq)
1033 {
1034 	return iv_of_dmreq(cc, dmreq) + cc->iv_size;
1035 }
1036 
1037 static uint64_t *org_sector_of_dmreq(struct crypt_config *cc,
1038 		       struct dm_crypt_request *dmreq)
1039 {
1040 	u8 *ptr = iv_of_dmreq(cc, dmreq) + cc->iv_size + cc->iv_size;
1041 	return (uint64_t*) ptr;
1042 }
1043 
1044 static unsigned int *org_tag_of_dmreq(struct crypt_config *cc,
1045 		       struct dm_crypt_request *dmreq)
1046 {
1047 	u8 *ptr = iv_of_dmreq(cc, dmreq) + cc->iv_size +
1048 		  cc->iv_size + sizeof(uint64_t);
1049 	return (unsigned int*)ptr;
1050 }
1051 
1052 static void *tag_from_dmreq(struct crypt_config *cc,
1053 				struct dm_crypt_request *dmreq)
1054 {
1055 	struct convert_context *ctx = dmreq->ctx;
1056 	struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
1057 
1058 	return &io->integrity_metadata[*org_tag_of_dmreq(cc, dmreq) *
1059 		cc->on_disk_tag_size];
1060 }
1061 
1062 static void *iv_tag_from_dmreq(struct crypt_config *cc,
1063 			       struct dm_crypt_request *dmreq)
1064 {
1065 	return tag_from_dmreq(cc, dmreq) + cc->integrity_tag_size;
1066 }
1067 
1068 static int crypt_convert_block_aead(struct crypt_config *cc,
1069 				     struct convert_context *ctx,
1070 				     struct aead_request *req,
1071 				     unsigned int tag_offset)
1072 {
1073 	struct bio_vec bv_in = bio_iter_iovec(ctx->bio_in, ctx->iter_in);
1074 	struct bio_vec bv_out = bio_iter_iovec(ctx->bio_out, ctx->iter_out);
1075 	struct dm_crypt_request *dmreq;
1076 	u8 *iv, *org_iv, *tag_iv, *tag;
1077 	uint64_t *sector;
1078 	int r = 0;
1079 
1080 	BUG_ON(cc->integrity_iv_size && cc->integrity_iv_size != cc->iv_size);
1081 
1082 	/* Reject unexpected unaligned bio. */
1083 	if (unlikely(bv_in.bv_len & (cc->sector_size - 1)))
1084 		return -EIO;
1085 
1086 	dmreq = dmreq_of_req(cc, req);
1087 	dmreq->iv_sector = ctx->cc_sector;
1088 	if (test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags))
1089 		dmreq->iv_sector >>= cc->sector_shift;
1090 	dmreq->ctx = ctx;
1091 
1092 	*org_tag_of_dmreq(cc, dmreq) = tag_offset;
1093 
1094 	sector = org_sector_of_dmreq(cc, dmreq);
1095 	*sector = cpu_to_le64(ctx->cc_sector - cc->iv_offset);
1096 
1097 	iv = iv_of_dmreq(cc, dmreq);
1098 	org_iv = org_iv_of_dmreq(cc, dmreq);
1099 	tag = tag_from_dmreq(cc, dmreq);
1100 	tag_iv = iv_tag_from_dmreq(cc, dmreq);
1101 
1102 	/* AEAD request:
1103 	 *  |----- AAD -------|------ DATA -------|-- AUTH TAG --|
1104 	 *  | (authenticated) | (auth+encryption) |              |
1105 	 *  | sector_LE |  IV |  sector in/out    |  tag in/out  |
1106 	 */
1107 	sg_init_table(dmreq->sg_in, 4);
1108 	sg_set_buf(&dmreq->sg_in[0], sector, sizeof(uint64_t));
1109 	sg_set_buf(&dmreq->sg_in[1], org_iv, cc->iv_size);
1110 	sg_set_page(&dmreq->sg_in[2], bv_in.bv_page, cc->sector_size, bv_in.bv_offset);
1111 	sg_set_buf(&dmreq->sg_in[3], tag, cc->integrity_tag_size);
1112 
1113 	sg_init_table(dmreq->sg_out, 4);
1114 	sg_set_buf(&dmreq->sg_out[0], sector, sizeof(uint64_t));
1115 	sg_set_buf(&dmreq->sg_out[1], org_iv, cc->iv_size);
1116 	sg_set_page(&dmreq->sg_out[2], bv_out.bv_page, cc->sector_size, bv_out.bv_offset);
1117 	sg_set_buf(&dmreq->sg_out[3], tag, cc->integrity_tag_size);
1118 
1119 	if (cc->iv_gen_ops) {
1120 		/* For READs use IV stored in integrity metadata */
1121 		if (cc->integrity_iv_size && bio_data_dir(ctx->bio_in) != WRITE) {
1122 			memcpy(org_iv, tag_iv, cc->iv_size);
1123 		} else {
1124 			r = cc->iv_gen_ops->generator(cc, org_iv, dmreq);
1125 			if (r < 0)
1126 				return r;
1127 			/* Store generated IV in integrity metadata */
1128 			if (cc->integrity_iv_size)
1129 				memcpy(tag_iv, org_iv, cc->iv_size);
1130 		}
1131 		/* Working copy of IV, to be modified in crypto API */
1132 		memcpy(iv, org_iv, cc->iv_size);
1133 	}
1134 
1135 	aead_request_set_ad(req, sizeof(uint64_t) + cc->iv_size);
1136 	if (bio_data_dir(ctx->bio_in) == WRITE) {
1137 		aead_request_set_crypt(req, dmreq->sg_in, dmreq->sg_out,
1138 				       cc->sector_size, iv);
1139 		r = crypto_aead_encrypt(req);
1140 		if (cc->integrity_tag_size + cc->integrity_iv_size != cc->on_disk_tag_size)
1141 			memset(tag + cc->integrity_tag_size + cc->integrity_iv_size, 0,
1142 			       cc->on_disk_tag_size - (cc->integrity_tag_size + cc->integrity_iv_size));
1143 	} else {
1144 		aead_request_set_crypt(req, dmreq->sg_in, dmreq->sg_out,
1145 				       cc->sector_size + cc->integrity_tag_size, iv);
1146 		r = crypto_aead_decrypt(req);
1147 	}
1148 
1149 	if (r == -EBADMSG)
1150 		DMERR_LIMIT("INTEGRITY AEAD ERROR, sector %llu",
1151 			    (unsigned long long)le64_to_cpu(*sector));
1152 
1153 	if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
1154 		r = cc->iv_gen_ops->post(cc, org_iv, dmreq);
1155 
1156 	bio_advance_iter(ctx->bio_in, &ctx->iter_in, cc->sector_size);
1157 	bio_advance_iter(ctx->bio_out, &ctx->iter_out, cc->sector_size);
1158 
1159 	return r;
1160 }
1161 
1162 static int crypt_convert_block_skcipher(struct crypt_config *cc,
1163 					struct convert_context *ctx,
1164 					struct skcipher_request *req,
1165 					unsigned int tag_offset)
1166 {
1167 	struct bio_vec bv_in = bio_iter_iovec(ctx->bio_in, ctx->iter_in);
1168 	struct bio_vec bv_out = bio_iter_iovec(ctx->bio_out, ctx->iter_out);
1169 	struct scatterlist *sg_in, *sg_out;
1170 	struct dm_crypt_request *dmreq;
1171 	u8 *iv, *org_iv, *tag_iv;
1172 	uint64_t *sector;
1173 	int r = 0;
1174 
1175 	/* Reject unexpected unaligned bio. */
1176 	if (unlikely(bv_in.bv_len & (cc->sector_size - 1)))
1177 		return -EIO;
1178 
1179 	dmreq = dmreq_of_req(cc, req);
1180 	dmreq->iv_sector = ctx->cc_sector;
1181 	if (test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags))
1182 		dmreq->iv_sector >>= cc->sector_shift;
1183 	dmreq->ctx = ctx;
1184 
1185 	*org_tag_of_dmreq(cc, dmreq) = tag_offset;
1186 
1187 	iv = iv_of_dmreq(cc, dmreq);
1188 	org_iv = org_iv_of_dmreq(cc, dmreq);
1189 	tag_iv = iv_tag_from_dmreq(cc, dmreq);
1190 
1191 	sector = org_sector_of_dmreq(cc, dmreq);
1192 	*sector = cpu_to_le64(ctx->cc_sector - cc->iv_offset);
1193 
1194 	/* For skcipher we use only the first sg item */
1195 	sg_in  = &dmreq->sg_in[0];
1196 	sg_out = &dmreq->sg_out[0];
1197 
1198 	sg_init_table(sg_in, 1);
1199 	sg_set_page(sg_in, bv_in.bv_page, cc->sector_size, bv_in.bv_offset);
1200 
1201 	sg_init_table(sg_out, 1);
1202 	sg_set_page(sg_out, bv_out.bv_page, cc->sector_size, bv_out.bv_offset);
1203 
1204 	if (cc->iv_gen_ops) {
1205 		/* For READs use IV stored in integrity metadata */
1206 		if (cc->integrity_iv_size && bio_data_dir(ctx->bio_in) != WRITE) {
1207 			memcpy(org_iv, tag_iv, cc->integrity_iv_size);
1208 		} else {
1209 			r = cc->iv_gen_ops->generator(cc, org_iv, dmreq);
1210 			if (r < 0)
1211 				return r;
1212 			/* Store generated IV in integrity metadata */
1213 			if (cc->integrity_iv_size)
1214 				memcpy(tag_iv, org_iv, cc->integrity_iv_size);
1215 		}
1216 		/* Working copy of IV, to be modified in crypto API */
1217 		memcpy(iv, org_iv, cc->iv_size);
1218 	}
1219 
1220 	skcipher_request_set_crypt(req, sg_in, sg_out, cc->sector_size, iv);
1221 
1222 	if (bio_data_dir(ctx->bio_in) == WRITE)
1223 		r = crypto_skcipher_encrypt(req);
1224 	else
1225 		r = crypto_skcipher_decrypt(req);
1226 
1227 	if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
1228 		r = cc->iv_gen_ops->post(cc, org_iv, dmreq);
1229 
1230 	bio_advance_iter(ctx->bio_in, &ctx->iter_in, cc->sector_size);
1231 	bio_advance_iter(ctx->bio_out, &ctx->iter_out, cc->sector_size);
1232 
1233 	return r;
1234 }
1235 
1236 static void kcryptd_async_done(struct crypto_async_request *async_req,
1237 			       int error);
1238 
1239 static void crypt_alloc_req_skcipher(struct crypt_config *cc,
1240 				     struct convert_context *ctx)
1241 {
1242 	unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1);
1243 
1244 	if (!ctx->r.req)
1245 		ctx->r.req = mempool_alloc(&cc->req_pool, GFP_NOIO);
1246 
1247 	skcipher_request_set_tfm(ctx->r.req, cc->cipher_tfm.tfms[key_index]);
1248 
1249 	/*
1250 	 * Use REQ_MAY_BACKLOG so a cipher driver internally backlogs
1251 	 * requests if driver request queue is full.
1252 	 */
1253 	skcipher_request_set_callback(ctx->r.req,
1254 	    CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
1255 	    kcryptd_async_done, dmreq_of_req(cc, ctx->r.req));
1256 }
1257 
1258 static void crypt_alloc_req_aead(struct crypt_config *cc,
1259 				 struct convert_context *ctx)
1260 {
1261 	if (!ctx->r.req_aead)
1262 		ctx->r.req_aead = mempool_alloc(&cc->req_pool, GFP_NOIO);
1263 
1264 	aead_request_set_tfm(ctx->r.req_aead, cc->cipher_tfm.tfms_aead[0]);
1265 
1266 	/*
1267 	 * Use REQ_MAY_BACKLOG so a cipher driver internally backlogs
1268 	 * requests if driver request queue is full.
1269 	 */
1270 	aead_request_set_callback(ctx->r.req_aead,
1271 	    CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
1272 	    kcryptd_async_done, dmreq_of_req(cc, ctx->r.req_aead));
1273 }
1274 
1275 static void crypt_alloc_req(struct crypt_config *cc,
1276 			    struct convert_context *ctx)
1277 {
1278 	if (crypt_integrity_aead(cc))
1279 		crypt_alloc_req_aead(cc, ctx);
1280 	else
1281 		crypt_alloc_req_skcipher(cc, ctx);
1282 }
1283 
1284 static void crypt_free_req_skcipher(struct crypt_config *cc,
1285 				    struct skcipher_request *req, struct bio *base_bio)
1286 {
1287 	struct dm_crypt_io *io = dm_per_bio_data(base_bio, cc->per_bio_data_size);
1288 
1289 	if ((struct skcipher_request *)(io + 1) != req)
1290 		mempool_free(req, &cc->req_pool);
1291 }
1292 
1293 static void crypt_free_req_aead(struct crypt_config *cc,
1294 				struct aead_request *req, struct bio *base_bio)
1295 {
1296 	struct dm_crypt_io *io = dm_per_bio_data(base_bio, cc->per_bio_data_size);
1297 
1298 	if ((struct aead_request *)(io + 1) != req)
1299 		mempool_free(req, &cc->req_pool);
1300 }
1301 
1302 static void crypt_free_req(struct crypt_config *cc, void *req, struct bio *base_bio)
1303 {
1304 	if (crypt_integrity_aead(cc))
1305 		crypt_free_req_aead(cc, req, base_bio);
1306 	else
1307 		crypt_free_req_skcipher(cc, req, base_bio);
1308 }
1309 
1310 /*
1311  * Encrypt / decrypt data from one bio to another one (can be the same one)
1312  */
1313 static blk_status_t crypt_convert(struct crypt_config *cc,
1314 			 struct convert_context *ctx)
1315 {
1316 	unsigned int tag_offset = 0;
1317 	unsigned int sector_step = cc->sector_size >> SECTOR_SHIFT;
1318 	int r;
1319 
1320 	atomic_set(&ctx->cc_pending, 1);
1321 
1322 	while (ctx->iter_in.bi_size && ctx->iter_out.bi_size) {
1323 
1324 		crypt_alloc_req(cc, ctx);
1325 		atomic_inc(&ctx->cc_pending);
1326 
1327 		if (crypt_integrity_aead(cc))
1328 			r = crypt_convert_block_aead(cc, ctx, ctx->r.req_aead, tag_offset);
1329 		else
1330 			r = crypt_convert_block_skcipher(cc, ctx, ctx->r.req, tag_offset);
1331 
1332 		switch (r) {
1333 		/*
1334 		 * The request was queued by a crypto driver
1335 		 * but the driver request queue is full, let's wait.
1336 		 */
1337 		case -EBUSY:
1338 			wait_for_completion(&ctx->restart);
1339 			reinit_completion(&ctx->restart);
1340 			/* fall through */
1341 		/*
1342 		 * The request is queued and processed asynchronously,
1343 		 * completion function kcryptd_async_done() will be called.
1344 		 */
1345 		case -EINPROGRESS:
1346 			ctx->r.req = NULL;
1347 			ctx->cc_sector += sector_step;
1348 			tag_offset++;
1349 			continue;
1350 		/*
1351 		 * The request was already processed (synchronously).
1352 		 */
1353 		case 0:
1354 			atomic_dec(&ctx->cc_pending);
1355 			ctx->cc_sector += sector_step;
1356 			tag_offset++;
1357 			cond_resched();
1358 			continue;
1359 		/*
1360 		 * There was a data integrity error.
1361 		 */
1362 		case -EBADMSG:
1363 			atomic_dec(&ctx->cc_pending);
1364 			return BLK_STS_PROTECTION;
1365 		/*
1366 		 * There was an error while processing the request.
1367 		 */
1368 		default:
1369 			atomic_dec(&ctx->cc_pending);
1370 			return BLK_STS_IOERR;
1371 		}
1372 	}
1373 
1374 	return 0;
1375 }
1376 
1377 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone);
1378 
1379 /*
1380  * Generate a new unfragmented bio with the given size
1381  * This should never violate the device limitations (but only because
1382  * max_segment_size is being constrained to PAGE_SIZE).
1383  *
1384  * This function may be called concurrently. If we allocate from the mempool
1385  * concurrently, there is a possibility of deadlock. For example, if we have
1386  * mempool of 256 pages, two processes, each wanting 256, pages allocate from
1387  * the mempool concurrently, it may deadlock in a situation where both processes
1388  * have allocated 128 pages and the mempool is exhausted.
1389  *
1390  * In order to avoid this scenario we allocate the pages under a mutex.
1391  *
1392  * In order to not degrade performance with excessive locking, we try
1393  * non-blocking allocations without a mutex first but on failure we fallback
1394  * to blocking allocations with a mutex.
1395  */
1396 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
1397 {
1398 	struct crypt_config *cc = io->cc;
1399 	struct bio *clone;
1400 	unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
1401 	gfp_t gfp_mask = GFP_NOWAIT | __GFP_HIGHMEM;
1402 	unsigned i, len, remaining_size;
1403 	struct page *page;
1404 
1405 retry:
1406 	if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM))
1407 		mutex_lock(&cc->bio_alloc_lock);
1408 
1409 	clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, &cc->bs);
1410 	if (!clone)
1411 		goto out;
1412 
1413 	clone_init(io, clone);
1414 
1415 	remaining_size = size;
1416 
1417 	for (i = 0; i < nr_iovecs; i++) {
1418 		page = mempool_alloc(&cc->page_pool, gfp_mask);
1419 		if (!page) {
1420 			crypt_free_buffer_pages(cc, clone);
1421 			bio_put(clone);
1422 			gfp_mask |= __GFP_DIRECT_RECLAIM;
1423 			goto retry;
1424 		}
1425 
1426 		len = (remaining_size > PAGE_SIZE) ? PAGE_SIZE : remaining_size;
1427 
1428 		bio_add_page(clone, page, len, 0);
1429 
1430 		remaining_size -= len;
1431 	}
1432 
1433 	/* Allocate space for integrity tags */
1434 	if (dm_crypt_integrity_io_alloc(io, clone)) {
1435 		crypt_free_buffer_pages(cc, clone);
1436 		bio_put(clone);
1437 		clone = NULL;
1438 	}
1439 out:
1440 	if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM))
1441 		mutex_unlock(&cc->bio_alloc_lock);
1442 
1443 	return clone;
1444 }
1445 
1446 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
1447 {
1448 	unsigned int i;
1449 	struct bio_vec *bv;
1450 
1451 	bio_for_each_segment_all(bv, clone, i) {
1452 		BUG_ON(!bv->bv_page);
1453 		mempool_free(bv->bv_page, &cc->page_pool);
1454 	}
1455 }
1456 
1457 static void crypt_io_init(struct dm_crypt_io *io, struct crypt_config *cc,
1458 			  struct bio *bio, sector_t sector)
1459 {
1460 	io->cc = cc;
1461 	io->base_bio = bio;
1462 	io->sector = sector;
1463 	io->error = 0;
1464 	io->ctx.r.req = NULL;
1465 	io->integrity_metadata = NULL;
1466 	io->integrity_metadata_from_pool = false;
1467 	atomic_set(&io->io_pending, 0);
1468 }
1469 
1470 static void crypt_inc_pending(struct dm_crypt_io *io)
1471 {
1472 	atomic_inc(&io->io_pending);
1473 }
1474 
1475 /*
1476  * One of the bios was finished. Check for completion of
1477  * the whole request and correctly clean up the buffer.
1478  */
1479 static void crypt_dec_pending(struct dm_crypt_io *io)
1480 {
1481 	struct crypt_config *cc = io->cc;
1482 	struct bio *base_bio = io->base_bio;
1483 	blk_status_t error = io->error;
1484 
1485 	if (!atomic_dec_and_test(&io->io_pending))
1486 		return;
1487 
1488 	if (io->ctx.r.req)
1489 		crypt_free_req(cc, io->ctx.r.req, base_bio);
1490 
1491 	if (unlikely(io->integrity_metadata_from_pool))
1492 		mempool_free(io->integrity_metadata, &io->cc->tag_pool);
1493 	else
1494 		kfree(io->integrity_metadata);
1495 
1496 	base_bio->bi_status = error;
1497 	bio_endio(base_bio);
1498 }
1499 
1500 /*
1501  * kcryptd/kcryptd_io:
1502  *
1503  * Needed because it would be very unwise to do decryption in an
1504  * interrupt context.
1505  *
1506  * kcryptd performs the actual encryption or decryption.
1507  *
1508  * kcryptd_io performs the IO submission.
1509  *
1510  * They must be separated as otherwise the final stages could be
1511  * starved by new requests which can block in the first stages due
1512  * to memory allocation.
1513  *
1514  * The work is done per CPU global for all dm-crypt instances.
1515  * They should not depend on each other and do not block.
1516  */
1517 static void crypt_endio(struct bio *clone)
1518 {
1519 	struct dm_crypt_io *io = clone->bi_private;
1520 	struct crypt_config *cc = io->cc;
1521 	unsigned rw = bio_data_dir(clone);
1522 	blk_status_t error;
1523 
1524 	/*
1525 	 * free the processed pages
1526 	 */
1527 	if (rw == WRITE)
1528 		crypt_free_buffer_pages(cc, clone);
1529 
1530 	error = clone->bi_status;
1531 	bio_put(clone);
1532 
1533 	if (rw == READ && !error) {
1534 		kcryptd_queue_crypt(io);
1535 		return;
1536 	}
1537 
1538 	if (unlikely(error))
1539 		io->error = error;
1540 
1541 	crypt_dec_pending(io);
1542 }
1543 
1544 static void clone_init(struct dm_crypt_io *io, struct bio *clone)
1545 {
1546 	struct crypt_config *cc = io->cc;
1547 
1548 	clone->bi_private = io;
1549 	clone->bi_end_io  = crypt_endio;
1550 	bio_set_dev(clone, cc->dev->bdev);
1551 	clone->bi_opf	  = io->base_bio->bi_opf;
1552 }
1553 
1554 static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
1555 {
1556 	struct crypt_config *cc = io->cc;
1557 	struct bio *clone;
1558 
1559 	/*
1560 	 * We need the original biovec array in order to decrypt
1561 	 * the whole bio data *afterwards* -- thanks to immutable
1562 	 * biovecs we don't need to worry about the block layer
1563 	 * modifying the biovec array; so leverage bio_clone_fast().
1564 	 */
1565 	clone = bio_clone_fast(io->base_bio, gfp, &cc->bs);
1566 	if (!clone)
1567 		return 1;
1568 
1569 	crypt_inc_pending(io);
1570 
1571 	clone_init(io, clone);
1572 	clone->bi_iter.bi_sector = cc->start + io->sector;
1573 
1574 	if (dm_crypt_integrity_io_alloc(io, clone)) {
1575 		crypt_dec_pending(io);
1576 		bio_put(clone);
1577 		return 1;
1578 	}
1579 
1580 	generic_make_request(clone);
1581 	return 0;
1582 }
1583 
1584 static void kcryptd_io_read_work(struct work_struct *work)
1585 {
1586 	struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1587 
1588 	crypt_inc_pending(io);
1589 	if (kcryptd_io_read(io, GFP_NOIO))
1590 		io->error = BLK_STS_RESOURCE;
1591 	crypt_dec_pending(io);
1592 }
1593 
1594 static void kcryptd_queue_read(struct dm_crypt_io *io)
1595 {
1596 	struct crypt_config *cc = io->cc;
1597 
1598 	INIT_WORK(&io->work, kcryptd_io_read_work);
1599 	queue_work(cc->io_queue, &io->work);
1600 }
1601 
1602 static void kcryptd_io_write(struct dm_crypt_io *io)
1603 {
1604 	struct bio *clone = io->ctx.bio_out;
1605 
1606 	generic_make_request(clone);
1607 }
1608 
1609 #define crypt_io_from_node(node) rb_entry((node), struct dm_crypt_io, rb_node)
1610 
1611 static int dmcrypt_write(void *data)
1612 {
1613 	struct crypt_config *cc = data;
1614 	struct dm_crypt_io *io;
1615 
1616 	while (1) {
1617 		struct rb_root write_tree;
1618 		struct blk_plug plug;
1619 
1620 		spin_lock_irq(&cc->write_thread_lock);
1621 continue_locked:
1622 
1623 		if (!RB_EMPTY_ROOT(&cc->write_tree))
1624 			goto pop_from_list;
1625 
1626 		set_current_state(TASK_INTERRUPTIBLE);
1627 
1628 		spin_unlock_irq(&cc->write_thread_lock);
1629 
1630 		if (unlikely(kthread_should_stop())) {
1631 			set_current_state(TASK_RUNNING);
1632 			break;
1633 		}
1634 
1635 		schedule();
1636 
1637 		set_current_state(TASK_RUNNING);
1638 		spin_lock_irq(&cc->write_thread_lock);
1639 		goto continue_locked;
1640 
1641 pop_from_list:
1642 		write_tree = cc->write_tree;
1643 		cc->write_tree = RB_ROOT;
1644 		spin_unlock_irq(&cc->write_thread_lock);
1645 
1646 		BUG_ON(rb_parent(write_tree.rb_node));
1647 
1648 		/*
1649 		 * Note: we cannot walk the tree here with rb_next because
1650 		 * the structures may be freed when kcryptd_io_write is called.
1651 		 */
1652 		blk_start_plug(&plug);
1653 		do {
1654 			io = crypt_io_from_node(rb_first(&write_tree));
1655 			rb_erase(&io->rb_node, &write_tree);
1656 			kcryptd_io_write(io);
1657 		} while (!RB_EMPTY_ROOT(&write_tree));
1658 		blk_finish_plug(&plug);
1659 	}
1660 	return 0;
1661 }
1662 
1663 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
1664 {
1665 	struct bio *clone = io->ctx.bio_out;
1666 	struct crypt_config *cc = io->cc;
1667 	unsigned long flags;
1668 	sector_t sector;
1669 	struct rb_node **rbp, *parent;
1670 
1671 	if (unlikely(io->error)) {
1672 		crypt_free_buffer_pages(cc, clone);
1673 		bio_put(clone);
1674 		crypt_dec_pending(io);
1675 		return;
1676 	}
1677 
1678 	/* crypt_convert should have filled the clone bio */
1679 	BUG_ON(io->ctx.iter_out.bi_size);
1680 
1681 	clone->bi_iter.bi_sector = cc->start + io->sector;
1682 
1683 	if (likely(!async) && test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) {
1684 		generic_make_request(clone);
1685 		return;
1686 	}
1687 
1688 	spin_lock_irqsave(&cc->write_thread_lock, flags);
1689 	if (RB_EMPTY_ROOT(&cc->write_tree))
1690 		wake_up_process(cc->write_thread);
1691 	rbp = &cc->write_tree.rb_node;
1692 	parent = NULL;
1693 	sector = io->sector;
1694 	while (*rbp) {
1695 		parent = *rbp;
1696 		if (sector < crypt_io_from_node(parent)->sector)
1697 			rbp = &(*rbp)->rb_left;
1698 		else
1699 			rbp = &(*rbp)->rb_right;
1700 	}
1701 	rb_link_node(&io->rb_node, parent, rbp);
1702 	rb_insert_color(&io->rb_node, &cc->write_tree);
1703 	spin_unlock_irqrestore(&cc->write_thread_lock, flags);
1704 }
1705 
1706 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
1707 {
1708 	struct crypt_config *cc = io->cc;
1709 	struct bio *clone;
1710 	int crypt_finished;
1711 	sector_t sector = io->sector;
1712 	blk_status_t r;
1713 
1714 	/*
1715 	 * Prevent io from disappearing until this function completes.
1716 	 */
1717 	crypt_inc_pending(io);
1718 	crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
1719 
1720 	clone = crypt_alloc_buffer(io, io->base_bio->bi_iter.bi_size);
1721 	if (unlikely(!clone)) {
1722 		io->error = BLK_STS_IOERR;
1723 		goto dec;
1724 	}
1725 
1726 	io->ctx.bio_out = clone;
1727 	io->ctx.iter_out = clone->bi_iter;
1728 
1729 	sector += bio_sectors(clone);
1730 
1731 	crypt_inc_pending(io);
1732 	r = crypt_convert(cc, &io->ctx);
1733 	if (r)
1734 		io->error = r;
1735 	crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending);
1736 
1737 	/* Encryption was already finished, submit io now */
1738 	if (crypt_finished) {
1739 		kcryptd_crypt_write_io_submit(io, 0);
1740 		io->sector = sector;
1741 	}
1742 
1743 dec:
1744 	crypt_dec_pending(io);
1745 }
1746 
1747 static void kcryptd_crypt_read_done(struct dm_crypt_io *io)
1748 {
1749 	crypt_dec_pending(io);
1750 }
1751 
1752 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
1753 {
1754 	struct crypt_config *cc = io->cc;
1755 	blk_status_t r;
1756 
1757 	crypt_inc_pending(io);
1758 
1759 	crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
1760 			   io->sector);
1761 
1762 	r = crypt_convert(cc, &io->ctx);
1763 	if (r)
1764 		io->error = r;
1765 
1766 	if (atomic_dec_and_test(&io->ctx.cc_pending))
1767 		kcryptd_crypt_read_done(io);
1768 
1769 	crypt_dec_pending(io);
1770 }
1771 
1772 static void kcryptd_async_done(struct crypto_async_request *async_req,
1773 			       int error)
1774 {
1775 	struct dm_crypt_request *dmreq = async_req->data;
1776 	struct convert_context *ctx = dmreq->ctx;
1777 	struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
1778 	struct crypt_config *cc = io->cc;
1779 
1780 	/*
1781 	 * A request from crypto driver backlog is going to be processed now,
1782 	 * finish the completion and continue in crypt_convert().
1783 	 * (Callback will be called for the second time for this request.)
1784 	 */
1785 	if (error == -EINPROGRESS) {
1786 		complete(&ctx->restart);
1787 		return;
1788 	}
1789 
1790 	if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
1791 		error = cc->iv_gen_ops->post(cc, org_iv_of_dmreq(cc, dmreq), dmreq);
1792 
1793 	if (error == -EBADMSG) {
1794 		DMERR_LIMIT("INTEGRITY AEAD ERROR, sector %llu",
1795 			    (unsigned long long)le64_to_cpu(*org_sector_of_dmreq(cc, dmreq)));
1796 		io->error = BLK_STS_PROTECTION;
1797 	} else if (error < 0)
1798 		io->error = BLK_STS_IOERR;
1799 
1800 	crypt_free_req(cc, req_of_dmreq(cc, dmreq), io->base_bio);
1801 
1802 	if (!atomic_dec_and_test(&ctx->cc_pending))
1803 		return;
1804 
1805 	if (bio_data_dir(io->base_bio) == READ)
1806 		kcryptd_crypt_read_done(io);
1807 	else
1808 		kcryptd_crypt_write_io_submit(io, 1);
1809 }
1810 
1811 static void kcryptd_crypt(struct work_struct *work)
1812 {
1813 	struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1814 
1815 	if (bio_data_dir(io->base_bio) == READ)
1816 		kcryptd_crypt_read_convert(io);
1817 	else
1818 		kcryptd_crypt_write_convert(io);
1819 }
1820 
1821 static void kcryptd_queue_crypt(struct dm_crypt_io *io)
1822 {
1823 	struct crypt_config *cc = io->cc;
1824 
1825 	INIT_WORK(&io->work, kcryptd_crypt);
1826 	queue_work(cc->crypt_queue, &io->work);
1827 }
1828 
1829 static void crypt_free_tfms_aead(struct crypt_config *cc)
1830 {
1831 	if (!cc->cipher_tfm.tfms_aead)
1832 		return;
1833 
1834 	if (cc->cipher_tfm.tfms_aead[0] && !IS_ERR(cc->cipher_tfm.tfms_aead[0])) {
1835 		crypto_free_aead(cc->cipher_tfm.tfms_aead[0]);
1836 		cc->cipher_tfm.tfms_aead[0] = NULL;
1837 	}
1838 
1839 	kfree(cc->cipher_tfm.tfms_aead);
1840 	cc->cipher_tfm.tfms_aead = NULL;
1841 }
1842 
1843 static void crypt_free_tfms_skcipher(struct crypt_config *cc)
1844 {
1845 	unsigned i;
1846 
1847 	if (!cc->cipher_tfm.tfms)
1848 		return;
1849 
1850 	for (i = 0; i < cc->tfms_count; i++)
1851 		if (cc->cipher_tfm.tfms[i] && !IS_ERR(cc->cipher_tfm.tfms[i])) {
1852 			crypto_free_skcipher(cc->cipher_tfm.tfms[i]);
1853 			cc->cipher_tfm.tfms[i] = NULL;
1854 		}
1855 
1856 	kfree(cc->cipher_tfm.tfms);
1857 	cc->cipher_tfm.tfms = NULL;
1858 }
1859 
1860 static void crypt_free_tfms(struct crypt_config *cc)
1861 {
1862 	if (crypt_integrity_aead(cc))
1863 		crypt_free_tfms_aead(cc);
1864 	else
1865 		crypt_free_tfms_skcipher(cc);
1866 }
1867 
1868 static int crypt_alloc_tfms_skcipher(struct crypt_config *cc, char *ciphermode)
1869 {
1870 	unsigned i;
1871 	int err;
1872 
1873 	cc->cipher_tfm.tfms = kcalloc(cc->tfms_count,
1874 				      sizeof(struct crypto_skcipher *),
1875 				      GFP_KERNEL);
1876 	if (!cc->cipher_tfm.tfms)
1877 		return -ENOMEM;
1878 
1879 	for (i = 0; i < cc->tfms_count; i++) {
1880 		cc->cipher_tfm.tfms[i] = crypto_alloc_skcipher(ciphermode, 0, 0);
1881 		if (IS_ERR(cc->cipher_tfm.tfms[i])) {
1882 			err = PTR_ERR(cc->cipher_tfm.tfms[i]);
1883 			crypt_free_tfms(cc);
1884 			return err;
1885 		}
1886 	}
1887 
1888 	return 0;
1889 }
1890 
1891 static int crypt_alloc_tfms_aead(struct crypt_config *cc, char *ciphermode)
1892 {
1893 	int err;
1894 
1895 	cc->cipher_tfm.tfms = kmalloc(sizeof(struct crypto_aead *), GFP_KERNEL);
1896 	if (!cc->cipher_tfm.tfms)
1897 		return -ENOMEM;
1898 
1899 	cc->cipher_tfm.tfms_aead[0] = crypto_alloc_aead(ciphermode, 0, 0);
1900 	if (IS_ERR(cc->cipher_tfm.tfms_aead[0])) {
1901 		err = PTR_ERR(cc->cipher_tfm.tfms_aead[0]);
1902 		crypt_free_tfms(cc);
1903 		return err;
1904 	}
1905 
1906 	return 0;
1907 }
1908 
1909 static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode)
1910 {
1911 	if (crypt_integrity_aead(cc))
1912 		return crypt_alloc_tfms_aead(cc, ciphermode);
1913 	else
1914 		return crypt_alloc_tfms_skcipher(cc, ciphermode);
1915 }
1916 
1917 static unsigned crypt_subkey_size(struct crypt_config *cc)
1918 {
1919 	return (cc->key_size - cc->key_extra_size) >> ilog2(cc->tfms_count);
1920 }
1921 
1922 static unsigned crypt_authenckey_size(struct crypt_config *cc)
1923 {
1924 	return crypt_subkey_size(cc) + RTA_SPACE(sizeof(struct crypto_authenc_key_param));
1925 }
1926 
1927 /*
1928  * If AEAD is composed like authenc(hmac(sha256),xts(aes)),
1929  * the key must be for some reason in special format.
1930  * This funcion converts cc->key to this special format.
1931  */
1932 static void crypt_copy_authenckey(char *p, const void *key,
1933 				  unsigned enckeylen, unsigned authkeylen)
1934 {
1935 	struct crypto_authenc_key_param *param;
1936 	struct rtattr *rta;
1937 
1938 	rta = (struct rtattr *)p;
1939 	param = RTA_DATA(rta);
1940 	param->enckeylen = cpu_to_be32(enckeylen);
1941 	rta->rta_len = RTA_LENGTH(sizeof(*param));
1942 	rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1943 	p += RTA_SPACE(sizeof(*param));
1944 	memcpy(p, key + enckeylen, authkeylen);
1945 	p += authkeylen;
1946 	memcpy(p, key, enckeylen);
1947 }
1948 
1949 static int crypt_setkey(struct crypt_config *cc)
1950 {
1951 	unsigned subkey_size;
1952 	int err = 0, i, r;
1953 
1954 	/* Ignore extra keys (which are used for IV etc) */
1955 	subkey_size = crypt_subkey_size(cc);
1956 
1957 	if (crypt_integrity_hmac(cc)) {
1958 		if (subkey_size < cc->key_mac_size)
1959 			return -EINVAL;
1960 
1961 		crypt_copy_authenckey(cc->authenc_key, cc->key,
1962 				      subkey_size - cc->key_mac_size,
1963 				      cc->key_mac_size);
1964 	}
1965 
1966 	for (i = 0; i < cc->tfms_count; i++) {
1967 		if (crypt_integrity_hmac(cc))
1968 			r = crypto_aead_setkey(cc->cipher_tfm.tfms_aead[i],
1969 				cc->authenc_key, crypt_authenckey_size(cc));
1970 		else if (crypt_integrity_aead(cc))
1971 			r = crypto_aead_setkey(cc->cipher_tfm.tfms_aead[i],
1972 					       cc->key + (i * subkey_size),
1973 					       subkey_size);
1974 		else
1975 			r = crypto_skcipher_setkey(cc->cipher_tfm.tfms[i],
1976 						   cc->key + (i * subkey_size),
1977 						   subkey_size);
1978 		if (r)
1979 			err = r;
1980 	}
1981 
1982 	if (crypt_integrity_hmac(cc))
1983 		memzero_explicit(cc->authenc_key, crypt_authenckey_size(cc));
1984 
1985 	return err;
1986 }
1987 
1988 #ifdef CONFIG_KEYS
1989 
1990 static bool contains_whitespace(const char *str)
1991 {
1992 	while (*str)
1993 		if (isspace(*str++))
1994 			return true;
1995 	return false;
1996 }
1997 
1998 static int crypt_set_keyring_key(struct crypt_config *cc, const char *key_string)
1999 {
2000 	char *new_key_string, *key_desc;
2001 	int ret;
2002 	struct key *key;
2003 	const struct user_key_payload *ukp;
2004 
2005 	/*
2006 	 * Reject key_string with whitespace. dm core currently lacks code for
2007 	 * proper whitespace escaping in arguments on DM_TABLE_STATUS path.
2008 	 */
2009 	if (contains_whitespace(key_string)) {
2010 		DMERR("whitespace chars not allowed in key string");
2011 		return -EINVAL;
2012 	}
2013 
2014 	/* look for next ':' separating key_type from key_description */
2015 	key_desc = strpbrk(key_string, ":");
2016 	if (!key_desc || key_desc == key_string || !strlen(key_desc + 1))
2017 		return -EINVAL;
2018 
2019 	if (strncmp(key_string, "logon:", key_desc - key_string + 1) &&
2020 	    strncmp(key_string, "user:", key_desc - key_string + 1))
2021 		return -EINVAL;
2022 
2023 	new_key_string = kstrdup(key_string, GFP_KERNEL);
2024 	if (!new_key_string)
2025 		return -ENOMEM;
2026 
2027 	key = request_key(key_string[0] == 'l' ? &key_type_logon : &key_type_user,
2028 			  key_desc + 1, NULL);
2029 	if (IS_ERR(key)) {
2030 		kzfree(new_key_string);
2031 		return PTR_ERR(key);
2032 	}
2033 
2034 	down_read(&key->sem);
2035 
2036 	ukp = user_key_payload_locked(key);
2037 	if (!ukp) {
2038 		up_read(&key->sem);
2039 		key_put(key);
2040 		kzfree(new_key_string);
2041 		return -EKEYREVOKED;
2042 	}
2043 
2044 	if (cc->key_size != ukp->datalen) {
2045 		up_read(&key->sem);
2046 		key_put(key);
2047 		kzfree(new_key_string);
2048 		return -EINVAL;
2049 	}
2050 
2051 	memcpy(cc->key, ukp->data, cc->key_size);
2052 
2053 	up_read(&key->sem);
2054 	key_put(key);
2055 
2056 	/* clear the flag since following operations may invalidate previously valid key */
2057 	clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
2058 
2059 	ret = crypt_setkey(cc);
2060 
2061 	if (!ret) {
2062 		set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
2063 		kzfree(cc->key_string);
2064 		cc->key_string = new_key_string;
2065 	} else
2066 		kzfree(new_key_string);
2067 
2068 	return ret;
2069 }
2070 
2071 static int get_key_size(char **key_string)
2072 {
2073 	char *colon, dummy;
2074 	int ret;
2075 
2076 	if (*key_string[0] != ':')
2077 		return strlen(*key_string) >> 1;
2078 
2079 	/* look for next ':' in key string */
2080 	colon = strpbrk(*key_string + 1, ":");
2081 	if (!colon)
2082 		return -EINVAL;
2083 
2084 	if (sscanf(*key_string + 1, "%u%c", &ret, &dummy) != 2 || dummy != ':')
2085 		return -EINVAL;
2086 
2087 	*key_string = colon;
2088 
2089 	/* remaining key string should be :<logon|user>:<key_desc> */
2090 
2091 	return ret;
2092 }
2093 
2094 #else
2095 
2096 static int crypt_set_keyring_key(struct crypt_config *cc, const char *key_string)
2097 {
2098 	return -EINVAL;
2099 }
2100 
2101 static int get_key_size(char **key_string)
2102 {
2103 	return (*key_string[0] == ':') ? -EINVAL : strlen(*key_string) >> 1;
2104 }
2105 
2106 #endif
2107 
2108 static int crypt_set_key(struct crypt_config *cc, char *key)
2109 {
2110 	int r = -EINVAL;
2111 	int key_string_len = strlen(key);
2112 
2113 	/* Hyphen (which gives a key_size of zero) means there is no key. */
2114 	if (!cc->key_size && strcmp(key, "-"))
2115 		goto out;
2116 
2117 	/* ':' means the key is in kernel keyring, short-circuit normal key processing */
2118 	if (key[0] == ':') {
2119 		r = crypt_set_keyring_key(cc, key + 1);
2120 		goto out;
2121 	}
2122 
2123 	/* clear the flag since following operations may invalidate previously valid key */
2124 	clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
2125 
2126 	/* wipe references to any kernel keyring key */
2127 	kzfree(cc->key_string);
2128 	cc->key_string = NULL;
2129 
2130 	/* Decode key from its hex representation. */
2131 	if (cc->key_size && hex2bin(cc->key, key, cc->key_size) < 0)
2132 		goto out;
2133 
2134 	r = crypt_setkey(cc);
2135 	if (!r)
2136 		set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
2137 
2138 out:
2139 	/* Hex key string not needed after here, so wipe it. */
2140 	memset(key, '0', key_string_len);
2141 
2142 	return r;
2143 }
2144 
2145 static int crypt_wipe_key(struct crypt_config *cc)
2146 {
2147 	int r;
2148 
2149 	clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
2150 	get_random_bytes(&cc->key, cc->key_size);
2151 	kzfree(cc->key_string);
2152 	cc->key_string = NULL;
2153 	r = crypt_setkey(cc);
2154 	memset(&cc->key, 0, cc->key_size * sizeof(u8));
2155 
2156 	return r;
2157 }
2158 
2159 static void crypt_calculate_pages_per_client(void)
2160 {
2161 	unsigned long pages = (totalram_pages - totalhigh_pages) * DM_CRYPT_MEMORY_PERCENT / 100;
2162 
2163 	if (!dm_crypt_clients_n)
2164 		return;
2165 
2166 	pages /= dm_crypt_clients_n;
2167 	if (pages < DM_CRYPT_MIN_PAGES_PER_CLIENT)
2168 		pages = DM_CRYPT_MIN_PAGES_PER_CLIENT;
2169 	dm_crypt_pages_per_client = pages;
2170 }
2171 
2172 static void *crypt_page_alloc(gfp_t gfp_mask, void *pool_data)
2173 {
2174 	struct crypt_config *cc = pool_data;
2175 	struct page *page;
2176 
2177 	if (unlikely(percpu_counter_compare(&cc->n_allocated_pages, dm_crypt_pages_per_client) >= 0) &&
2178 	    likely(gfp_mask & __GFP_NORETRY))
2179 		return NULL;
2180 
2181 	page = alloc_page(gfp_mask);
2182 	if (likely(page != NULL))
2183 		percpu_counter_add(&cc->n_allocated_pages, 1);
2184 
2185 	return page;
2186 }
2187 
2188 static void crypt_page_free(void *page, void *pool_data)
2189 {
2190 	struct crypt_config *cc = pool_data;
2191 
2192 	__free_page(page);
2193 	percpu_counter_sub(&cc->n_allocated_pages, 1);
2194 }
2195 
2196 static void crypt_dtr(struct dm_target *ti)
2197 {
2198 	struct crypt_config *cc = ti->private;
2199 
2200 	ti->private = NULL;
2201 
2202 	if (!cc)
2203 		return;
2204 
2205 	if (cc->write_thread)
2206 		kthread_stop(cc->write_thread);
2207 
2208 	if (cc->io_queue)
2209 		destroy_workqueue(cc->io_queue);
2210 	if (cc->crypt_queue)
2211 		destroy_workqueue(cc->crypt_queue);
2212 
2213 	crypt_free_tfms(cc);
2214 
2215 	bioset_exit(&cc->bs);
2216 
2217 	mempool_exit(&cc->page_pool);
2218 	mempool_exit(&cc->req_pool);
2219 	mempool_exit(&cc->tag_pool);
2220 
2221 	WARN_ON(percpu_counter_sum(&cc->n_allocated_pages) != 0);
2222 	percpu_counter_destroy(&cc->n_allocated_pages);
2223 
2224 	if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
2225 		cc->iv_gen_ops->dtr(cc);
2226 
2227 	if (cc->dev)
2228 		dm_put_device(ti, cc->dev);
2229 
2230 	kzfree(cc->cipher);
2231 	kzfree(cc->cipher_string);
2232 	kzfree(cc->key_string);
2233 	kzfree(cc->cipher_auth);
2234 	kzfree(cc->authenc_key);
2235 
2236 	mutex_destroy(&cc->bio_alloc_lock);
2237 
2238 	/* Must zero key material before freeing */
2239 	kzfree(cc);
2240 
2241 	spin_lock(&dm_crypt_clients_lock);
2242 	WARN_ON(!dm_crypt_clients_n);
2243 	dm_crypt_clients_n--;
2244 	crypt_calculate_pages_per_client();
2245 	spin_unlock(&dm_crypt_clients_lock);
2246 }
2247 
2248 static int crypt_ctr_ivmode(struct dm_target *ti, const char *ivmode)
2249 {
2250 	struct crypt_config *cc = ti->private;
2251 
2252 	if (crypt_integrity_aead(cc))
2253 		cc->iv_size = crypto_aead_ivsize(any_tfm_aead(cc));
2254 	else
2255 		cc->iv_size = crypto_skcipher_ivsize(any_tfm(cc));
2256 
2257 	if (cc->iv_size)
2258 		/* at least a 64 bit sector number should fit in our buffer */
2259 		cc->iv_size = max(cc->iv_size,
2260 				  (unsigned int)(sizeof(u64) / sizeof(u8)));
2261 	else if (ivmode) {
2262 		DMWARN("Selected cipher does not support IVs");
2263 		ivmode = NULL;
2264 	}
2265 
2266 	/* Choose ivmode, see comments at iv code. */
2267 	if (ivmode == NULL)
2268 		cc->iv_gen_ops = NULL;
2269 	else if (strcmp(ivmode, "plain") == 0)
2270 		cc->iv_gen_ops = &crypt_iv_plain_ops;
2271 	else if (strcmp(ivmode, "plain64") == 0)
2272 		cc->iv_gen_ops = &crypt_iv_plain64_ops;
2273 	else if (strcmp(ivmode, "plain64be") == 0)
2274 		cc->iv_gen_ops = &crypt_iv_plain64be_ops;
2275 	else if (strcmp(ivmode, "essiv") == 0)
2276 		cc->iv_gen_ops = &crypt_iv_essiv_ops;
2277 	else if (strcmp(ivmode, "benbi") == 0)
2278 		cc->iv_gen_ops = &crypt_iv_benbi_ops;
2279 	else if (strcmp(ivmode, "null") == 0)
2280 		cc->iv_gen_ops = &crypt_iv_null_ops;
2281 	else if (strcmp(ivmode, "lmk") == 0) {
2282 		cc->iv_gen_ops = &crypt_iv_lmk_ops;
2283 		/*
2284 		 * Version 2 and 3 is recognised according
2285 		 * to length of provided multi-key string.
2286 		 * If present (version 3), last key is used as IV seed.
2287 		 * All keys (including IV seed) are always the same size.
2288 		 */
2289 		if (cc->key_size % cc->key_parts) {
2290 			cc->key_parts++;
2291 			cc->key_extra_size = cc->key_size / cc->key_parts;
2292 		}
2293 	} else if (strcmp(ivmode, "tcw") == 0) {
2294 		cc->iv_gen_ops = &crypt_iv_tcw_ops;
2295 		cc->key_parts += 2; /* IV + whitening */
2296 		cc->key_extra_size = cc->iv_size + TCW_WHITENING_SIZE;
2297 	} else if (strcmp(ivmode, "random") == 0) {
2298 		cc->iv_gen_ops = &crypt_iv_random_ops;
2299 		/* Need storage space in integrity fields. */
2300 		cc->integrity_iv_size = cc->iv_size;
2301 	} else {
2302 		ti->error = "Invalid IV mode";
2303 		return -EINVAL;
2304 	}
2305 
2306 	return 0;
2307 }
2308 
2309 /*
2310  * Workaround to parse cipher algorithm from crypto API spec.
2311  * The cc->cipher is currently used only in ESSIV.
2312  * This should be probably done by crypto-api calls (once available...)
2313  */
2314 static int crypt_ctr_blkdev_cipher(struct crypt_config *cc)
2315 {
2316 	const char *alg_name = NULL;
2317 	char *start, *end;
2318 
2319 	if (crypt_integrity_aead(cc)) {
2320 		alg_name = crypto_tfm_alg_name(crypto_aead_tfm(any_tfm_aead(cc)));
2321 		if (!alg_name)
2322 			return -EINVAL;
2323 		if (crypt_integrity_hmac(cc)) {
2324 			alg_name = strchr(alg_name, ',');
2325 			if (!alg_name)
2326 				return -EINVAL;
2327 		}
2328 		alg_name++;
2329 	} else {
2330 		alg_name = crypto_tfm_alg_name(crypto_skcipher_tfm(any_tfm(cc)));
2331 		if (!alg_name)
2332 			return -EINVAL;
2333 	}
2334 
2335 	start = strchr(alg_name, '(');
2336 	end = strchr(alg_name, ')');
2337 
2338 	if (!start && !end) {
2339 		cc->cipher = kstrdup(alg_name, GFP_KERNEL);
2340 		return cc->cipher ? 0 : -ENOMEM;
2341 	}
2342 
2343 	if (!start || !end || ++start >= end)
2344 		return -EINVAL;
2345 
2346 	cc->cipher = kzalloc(end - start + 1, GFP_KERNEL);
2347 	if (!cc->cipher)
2348 		return -ENOMEM;
2349 
2350 	strncpy(cc->cipher, start, end - start);
2351 
2352 	return 0;
2353 }
2354 
2355 /*
2356  * Workaround to parse HMAC algorithm from AEAD crypto API spec.
2357  * The HMAC is needed to calculate tag size (HMAC digest size).
2358  * This should be probably done by crypto-api calls (once available...)
2359  */
2360 static int crypt_ctr_auth_cipher(struct crypt_config *cc, char *cipher_api)
2361 {
2362 	char *start, *end, *mac_alg = NULL;
2363 	struct crypto_ahash *mac;
2364 
2365 	if (!strstarts(cipher_api, "authenc("))
2366 		return 0;
2367 
2368 	start = strchr(cipher_api, '(');
2369 	end = strchr(cipher_api, ',');
2370 	if (!start || !end || ++start > end)
2371 		return -EINVAL;
2372 
2373 	mac_alg = kzalloc(end - start + 1, GFP_KERNEL);
2374 	if (!mac_alg)
2375 		return -ENOMEM;
2376 	strncpy(mac_alg, start, end - start);
2377 
2378 	mac = crypto_alloc_ahash(mac_alg, 0, 0);
2379 	kfree(mac_alg);
2380 
2381 	if (IS_ERR(mac))
2382 		return PTR_ERR(mac);
2383 
2384 	cc->key_mac_size = crypto_ahash_digestsize(mac);
2385 	crypto_free_ahash(mac);
2386 
2387 	cc->authenc_key = kmalloc(crypt_authenckey_size(cc), GFP_KERNEL);
2388 	if (!cc->authenc_key)
2389 		return -ENOMEM;
2390 
2391 	return 0;
2392 }
2393 
2394 static int crypt_ctr_cipher_new(struct dm_target *ti, char *cipher_in, char *key,
2395 				char **ivmode, char **ivopts)
2396 {
2397 	struct crypt_config *cc = ti->private;
2398 	char *tmp, *cipher_api;
2399 	int ret = -EINVAL;
2400 
2401 	cc->tfms_count = 1;
2402 
2403 	/*
2404 	 * New format (capi: prefix)
2405 	 * capi:cipher_api_spec-iv:ivopts
2406 	 */
2407 	tmp = &cipher_in[strlen("capi:")];
2408 	cipher_api = strsep(&tmp, "-");
2409 	*ivmode = strsep(&tmp, ":");
2410 	*ivopts = tmp;
2411 
2412 	if (*ivmode && !strcmp(*ivmode, "lmk"))
2413 		cc->tfms_count = 64;
2414 
2415 	cc->key_parts = cc->tfms_count;
2416 
2417 	/* Allocate cipher */
2418 	ret = crypt_alloc_tfms(cc, cipher_api);
2419 	if (ret < 0) {
2420 		ti->error = "Error allocating crypto tfm";
2421 		return ret;
2422 	}
2423 
2424 	/* Alloc AEAD, can be used only in new format. */
2425 	if (crypt_integrity_aead(cc)) {
2426 		ret = crypt_ctr_auth_cipher(cc, cipher_api);
2427 		if (ret < 0) {
2428 			ti->error = "Invalid AEAD cipher spec";
2429 			return -ENOMEM;
2430 		}
2431 		cc->iv_size = crypto_aead_ivsize(any_tfm_aead(cc));
2432 	} else
2433 		cc->iv_size = crypto_skcipher_ivsize(any_tfm(cc));
2434 
2435 	ret = crypt_ctr_blkdev_cipher(cc);
2436 	if (ret < 0) {
2437 		ti->error = "Cannot allocate cipher string";
2438 		return -ENOMEM;
2439 	}
2440 
2441 	return 0;
2442 }
2443 
2444 static int crypt_ctr_cipher_old(struct dm_target *ti, char *cipher_in, char *key,
2445 				char **ivmode, char **ivopts)
2446 {
2447 	struct crypt_config *cc = ti->private;
2448 	char *tmp, *cipher, *chainmode, *keycount;
2449 	char *cipher_api = NULL;
2450 	int ret = -EINVAL;
2451 	char dummy;
2452 
2453 	if (strchr(cipher_in, '(') || crypt_integrity_aead(cc)) {
2454 		ti->error = "Bad cipher specification";
2455 		return -EINVAL;
2456 	}
2457 
2458 	/*
2459 	 * Legacy dm-crypt cipher specification
2460 	 * cipher[:keycount]-mode-iv:ivopts
2461 	 */
2462 	tmp = cipher_in;
2463 	keycount = strsep(&tmp, "-");
2464 	cipher = strsep(&keycount, ":");
2465 
2466 	if (!keycount)
2467 		cc->tfms_count = 1;
2468 	else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 ||
2469 		 !is_power_of_2(cc->tfms_count)) {
2470 		ti->error = "Bad cipher key count specification";
2471 		return -EINVAL;
2472 	}
2473 	cc->key_parts = cc->tfms_count;
2474 
2475 	cc->cipher = kstrdup(cipher, GFP_KERNEL);
2476 	if (!cc->cipher)
2477 		goto bad_mem;
2478 
2479 	chainmode = strsep(&tmp, "-");
2480 	*ivopts = strsep(&tmp, "-");
2481 	*ivmode = strsep(&*ivopts, ":");
2482 
2483 	if (tmp)
2484 		DMWARN("Ignoring unexpected additional cipher options");
2485 
2486 	/*
2487 	 * For compatibility with the original dm-crypt mapping format, if
2488 	 * only the cipher name is supplied, use cbc-plain.
2489 	 */
2490 	if (!chainmode || (!strcmp(chainmode, "plain") && !*ivmode)) {
2491 		chainmode = "cbc";
2492 		*ivmode = "plain";
2493 	}
2494 
2495 	if (strcmp(chainmode, "ecb") && !*ivmode) {
2496 		ti->error = "IV mechanism required";
2497 		return -EINVAL;
2498 	}
2499 
2500 	cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
2501 	if (!cipher_api)
2502 		goto bad_mem;
2503 
2504 	ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
2505 		       "%s(%s)", chainmode, cipher);
2506 	if (ret < 0) {
2507 		kfree(cipher_api);
2508 		goto bad_mem;
2509 	}
2510 
2511 	/* Allocate cipher */
2512 	ret = crypt_alloc_tfms(cc, cipher_api);
2513 	if (ret < 0) {
2514 		ti->error = "Error allocating crypto tfm";
2515 		kfree(cipher_api);
2516 		return ret;
2517 	}
2518 	kfree(cipher_api);
2519 
2520 	return 0;
2521 bad_mem:
2522 	ti->error = "Cannot allocate cipher strings";
2523 	return -ENOMEM;
2524 }
2525 
2526 static int crypt_ctr_cipher(struct dm_target *ti, char *cipher_in, char *key)
2527 {
2528 	struct crypt_config *cc = ti->private;
2529 	char *ivmode = NULL, *ivopts = NULL;
2530 	int ret;
2531 
2532 	cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
2533 	if (!cc->cipher_string) {
2534 		ti->error = "Cannot allocate cipher strings";
2535 		return -ENOMEM;
2536 	}
2537 
2538 	if (strstarts(cipher_in, "capi:"))
2539 		ret = crypt_ctr_cipher_new(ti, cipher_in, key, &ivmode, &ivopts);
2540 	else
2541 		ret = crypt_ctr_cipher_old(ti, cipher_in, key, &ivmode, &ivopts);
2542 	if (ret)
2543 		return ret;
2544 
2545 	/* Initialize IV */
2546 	ret = crypt_ctr_ivmode(ti, ivmode);
2547 	if (ret < 0)
2548 		return ret;
2549 
2550 	/* Initialize and set key */
2551 	ret = crypt_set_key(cc, key);
2552 	if (ret < 0) {
2553 		ti->error = "Error decoding and setting key";
2554 		return ret;
2555 	}
2556 
2557 	/* Allocate IV */
2558 	if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
2559 		ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
2560 		if (ret < 0) {
2561 			ti->error = "Error creating IV";
2562 			return ret;
2563 		}
2564 	}
2565 
2566 	/* Initialize IV (set keys for ESSIV etc) */
2567 	if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
2568 		ret = cc->iv_gen_ops->init(cc);
2569 		if (ret < 0) {
2570 			ti->error = "Error initialising IV";
2571 			return ret;
2572 		}
2573 	}
2574 
2575 	/* wipe the kernel key payload copy */
2576 	if (cc->key_string)
2577 		memset(cc->key, 0, cc->key_size * sizeof(u8));
2578 
2579 	return ret;
2580 }
2581 
2582 static int crypt_ctr_optional(struct dm_target *ti, unsigned int argc, char **argv)
2583 {
2584 	struct crypt_config *cc = ti->private;
2585 	struct dm_arg_set as;
2586 	static const struct dm_arg _args[] = {
2587 		{0, 6, "Invalid number of feature args"},
2588 	};
2589 	unsigned int opt_params, val;
2590 	const char *opt_string, *sval;
2591 	char dummy;
2592 	int ret;
2593 
2594 	/* Optional parameters */
2595 	as.argc = argc;
2596 	as.argv = argv;
2597 
2598 	ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
2599 	if (ret)
2600 		return ret;
2601 
2602 	while (opt_params--) {
2603 		opt_string = dm_shift_arg(&as);
2604 		if (!opt_string) {
2605 			ti->error = "Not enough feature arguments";
2606 			return -EINVAL;
2607 		}
2608 
2609 		if (!strcasecmp(opt_string, "allow_discards"))
2610 			ti->num_discard_bios = 1;
2611 
2612 		else if (!strcasecmp(opt_string, "same_cpu_crypt"))
2613 			set_bit(DM_CRYPT_SAME_CPU, &cc->flags);
2614 
2615 		else if (!strcasecmp(opt_string, "submit_from_crypt_cpus"))
2616 			set_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags);
2617 		else if (sscanf(opt_string, "integrity:%u:", &val) == 1) {
2618 			if (val == 0 || val > MAX_TAG_SIZE) {
2619 				ti->error = "Invalid integrity arguments";
2620 				return -EINVAL;
2621 			}
2622 			cc->on_disk_tag_size = val;
2623 			sval = strchr(opt_string + strlen("integrity:"), ':') + 1;
2624 			if (!strcasecmp(sval, "aead")) {
2625 				set_bit(CRYPT_MODE_INTEGRITY_AEAD, &cc->cipher_flags);
2626 			} else  if (strcasecmp(sval, "none")) {
2627 				ti->error = "Unknown integrity profile";
2628 				return -EINVAL;
2629 			}
2630 
2631 			cc->cipher_auth = kstrdup(sval, GFP_KERNEL);
2632 			if (!cc->cipher_auth)
2633 				return -ENOMEM;
2634 		} else if (sscanf(opt_string, "sector_size:%hu%c", &cc->sector_size, &dummy) == 1) {
2635 			if (cc->sector_size < (1 << SECTOR_SHIFT) ||
2636 			    cc->sector_size > 4096 ||
2637 			    (cc->sector_size & (cc->sector_size - 1))) {
2638 				ti->error = "Invalid feature value for sector_size";
2639 				return -EINVAL;
2640 			}
2641 			if (ti->len & ((cc->sector_size >> SECTOR_SHIFT) - 1)) {
2642 				ti->error = "Device size is not multiple of sector_size feature";
2643 				return -EINVAL;
2644 			}
2645 			cc->sector_shift = __ffs(cc->sector_size) - SECTOR_SHIFT;
2646 		} else if (!strcasecmp(opt_string, "iv_large_sectors"))
2647 			set_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags);
2648 		else {
2649 			ti->error = "Invalid feature arguments";
2650 			return -EINVAL;
2651 		}
2652 	}
2653 
2654 	return 0;
2655 }
2656 
2657 /*
2658  * Construct an encryption mapping:
2659  * <cipher> [<key>|:<key_size>:<user|logon>:<key_description>] <iv_offset> <dev_path> <start>
2660  */
2661 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
2662 {
2663 	struct crypt_config *cc;
2664 	int key_size;
2665 	unsigned int align_mask;
2666 	unsigned long long tmpll;
2667 	int ret;
2668 	size_t iv_size_padding, additional_req_size;
2669 	char dummy;
2670 
2671 	if (argc < 5) {
2672 		ti->error = "Not enough arguments";
2673 		return -EINVAL;
2674 	}
2675 
2676 	key_size = get_key_size(&argv[1]);
2677 	if (key_size < 0) {
2678 		ti->error = "Cannot parse key size";
2679 		return -EINVAL;
2680 	}
2681 
2682 	cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
2683 	if (!cc) {
2684 		ti->error = "Cannot allocate encryption context";
2685 		return -ENOMEM;
2686 	}
2687 	cc->key_size = key_size;
2688 	cc->sector_size = (1 << SECTOR_SHIFT);
2689 	cc->sector_shift = 0;
2690 
2691 	ti->private = cc;
2692 
2693 	spin_lock(&dm_crypt_clients_lock);
2694 	dm_crypt_clients_n++;
2695 	crypt_calculate_pages_per_client();
2696 	spin_unlock(&dm_crypt_clients_lock);
2697 
2698 	ret = percpu_counter_init(&cc->n_allocated_pages, 0, GFP_KERNEL);
2699 	if (ret < 0)
2700 		goto bad;
2701 
2702 	/* Optional parameters need to be read before cipher constructor */
2703 	if (argc > 5) {
2704 		ret = crypt_ctr_optional(ti, argc - 5, &argv[5]);
2705 		if (ret)
2706 			goto bad;
2707 	}
2708 
2709 	ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
2710 	if (ret < 0)
2711 		goto bad;
2712 
2713 	if (crypt_integrity_aead(cc)) {
2714 		cc->dmreq_start = sizeof(struct aead_request);
2715 		cc->dmreq_start += crypto_aead_reqsize(any_tfm_aead(cc));
2716 		align_mask = crypto_aead_alignmask(any_tfm_aead(cc));
2717 	} else {
2718 		cc->dmreq_start = sizeof(struct skcipher_request);
2719 		cc->dmreq_start += crypto_skcipher_reqsize(any_tfm(cc));
2720 		align_mask = crypto_skcipher_alignmask(any_tfm(cc));
2721 	}
2722 	cc->dmreq_start = ALIGN(cc->dmreq_start, __alignof__(struct dm_crypt_request));
2723 
2724 	if (align_mask < CRYPTO_MINALIGN) {
2725 		/* Allocate the padding exactly */
2726 		iv_size_padding = -(cc->dmreq_start + sizeof(struct dm_crypt_request))
2727 				& align_mask;
2728 	} else {
2729 		/*
2730 		 * If the cipher requires greater alignment than kmalloc
2731 		 * alignment, we don't know the exact position of the
2732 		 * initialization vector. We must assume worst case.
2733 		 */
2734 		iv_size_padding = align_mask;
2735 	}
2736 
2737 	/*  ...| IV + padding | original IV | original sec. number | bio tag offset | */
2738 	additional_req_size = sizeof(struct dm_crypt_request) +
2739 		iv_size_padding + cc->iv_size +
2740 		cc->iv_size +
2741 		sizeof(uint64_t) +
2742 		sizeof(unsigned int);
2743 
2744 	ret = mempool_init_kmalloc_pool(&cc->req_pool, MIN_IOS, cc->dmreq_start + additional_req_size);
2745 	if (ret) {
2746 		ti->error = "Cannot allocate crypt request mempool";
2747 		goto bad;
2748 	}
2749 
2750 	cc->per_bio_data_size = ti->per_io_data_size =
2751 		ALIGN(sizeof(struct dm_crypt_io) + cc->dmreq_start + additional_req_size,
2752 		      ARCH_KMALLOC_MINALIGN);
2753 
2754 	ret = mempool_init(&cc->page_pool, BIO_MAX_PAGES, crypt_page_alloc, crypt_page_free, cc);
2755 	if (ret) {
2756 		ti->error = "Cannot allocate page mempool";
2757 		goto bad;
2758 	}
2759 
2760 	ret = bioset_init(&cc->bs, MIN_IOS, 0, BIOSET_NEED_BVECS);
2761 	if (ret) {
2762 		ti->error = "Cannot allocate crypt bioset";
2763 		goto bad;
2764 	}
2765 
2766 	mutex_init(&cc->bio_alloc_lock);
2767 
2768 	ret = -EINVAL;
2769 	if ((sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) ||
2770 	    (tmpll & ((cc->sector_size >> SECTOR_SHIFT) - 1))) {
2771 		ti->error = "Invalid iv_offset sector";
2772 		goto bad;
2773 	}
2774 	cc->iv_offset = tmpll;
2775 
2776 	ret = dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev);
2777 	if (ret) {
2778 		ti->error = "Device lookup failed";
2779 		goto bad;
2780 	}
2781 
2782 	ret = -EINVAL;
2783 	if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
2784 		ti->error = "Invalid device sector";
2785 		goto bad;
2786 	}
2787 	cc->start = tmpll;
2788 
2789 	if (crypt_integrity_aead(cc) || cc->integrity_iv_size) {
2790 		ret = crypt_integrity_ctr(cc, ti);
2791 		if (ret)
2792 			goto bad;
2793 
2794 		cc->tag_pool_max_sectors = POOL_ENTRY_SIZE / cc->on_disk_tag_size;
2795 		if (!cc->tag_pool_max_sectors)
2796 			cc->tag_pool_max_sectors = 1;
2797 
2798 		ret = mempool_init_kmalloc_pool(&cc->tag_pool, MIN_IOS,
2799 			cc->tag_pool_max_sectors * cc->on_disk_tag_size);
2800 		if (ret) {
2801 			ti->error = "Cannot allocate integrity tags mempool";
2802 			goto bad;
2803 		}
2804 
2805 		cc->tag_pool_max_sectors <<= cc->sector_shift;
2806 	}
2807 
2808 	ret = -ENOMEM;
2809 	cc->io_queue = alloc_workqueue("kcryptd_io", WQ_HIGHPRI | WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1);
2810 	if (!cc->io_queue) {
2811 		ti->error = "Couldn't create kcryptd io queue";
2812 		goto bad;
2813 	}
2814 
2815 	if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
2816 		cc->crypt_queue = alloc_workqueue("kcryptd", WQ_HIGHPRI | WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1);
2817 	else
2818 		cc->crypt_queue = alloc_workqueue("kcryptd",
2819 						  WQ_HIGHPRI | WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND,
2820 						  num_online_cpus());
2821 	if (!cc->crypt_queue) {
2822 		ti->error = "Couldn't create kcryptd queue";
2823 		goto bad;
2824 	}
2825 
2826 	spin_lock_init(&cc->write_thread_lock);
2827 	cc->write_tree = RB_ROOT;
2828 
2829 	cc->write_thread = kthread_create(dmcrypt_write, cc, "dmcrypt_write");
2830 	if (IS_ERR(cc->write_thread)) {
2831 		ret = PTR_ERR(cc->write_thread);
2832 		cc->write_thread = NULL;
2833 		ti->error = "Couldn't spawn write thread";
2834 		goto bad;
2835 	}
2836 	wake_up_process(cc->write_thread);
2837 
2838 	ti->num_flush_bios = 1;
2839 
2840 	return 0;
2841 
2842 bad:
2843 	crypt_dtr(ti);
2844 	return ret;
2845 }
2846 
2847 static int crypt_map(struct dm_target *ti, struct bio *bio)
2848 {
2849 	struct dm_crypt_io *io;
2850 	struct crypt_config *cc = ti->private;
2851 
2852 	/*
2853 	 * If bio is REQ_PREFLUSH or REQ_OP_DISCARD, just bypass crypt queues.
2854 	 * - for REQ_PREFLUSH device-mapper core ensures that no IO is in-flight
2855 	 * - for REQ_OP_DISCARD caller must use flush if IO ordering matters
2856 	 */
2857 	if (unlikely(bio->bi_opf & REQ_PREFLUSH ||
2858 	    bio_op(bio) == REQ_OP_DISCARD)) {
2859 		bio_set_dev(bio, cc->dev->bdev);
2860 		if (bio_sectors(bio))
2861 			bio->bi_iter.bi_sector = cc->start +
2862 				dm_target_offset(ti, bio->bi_iter.bi_sector);
2863 		return DM_MAPIO_REMAPPED;
2864 	}
2865 
2866 	/*
2867 	 * Check if bio is too large, split as needed.
2868 	 */
2869 	if (unlikely(bio->bi_iter.bi_size > (BIO_MAX_PAGES << PAGE_SHIFT)) &&
2870 	    (bio_data_dir(bio) == WRITE || cc->on_disk_tag_size))
2871 		dm_accept_partial_bio(bio, ((BIO_MAX_PAGES << PAGE_SHIFT) >> SECTOR_SHIFT));
2872 
2873 	/*
2874 	 * Ensure that bio is a multiple of internal sector encryption size
2875 	 * and is aligned to this size as defined in IO hints.
2876 	 */
2877 	if (unlikely((bio->bi_iter.bi_sector & ((cc->sector_size >> SECTOR_SHIFT) - 1)) != 0))
2878 		return DM_MAPIO_KILL;
2879 
2880 	if (unlikely(bio->bi_iter.bi_size & (cc->sector_size - 1)))
2881 		return DM_MAPIO_KILL;
2882 
2883 	io = dm_per_bio_data(bio, cc->per_bio_data_size);
2884 	crypt_io_init(io, cc, bio, dm_target_offset(ti, bio->bi_iter.bi_sector));
2885 
2886 	if (cc->on_disk_tag_size) {
2887 		unsigned tag_len = cc->on_disk_tag_size * (bio_sectors(bio) >> cc->sector_shift);
2888 
2889 		if (unlikely(tag_len > KMALLOC_MAX_SIZE) ||
2890 		    unlikely(!(io->integrity_metadata = kmalloc(tag_len,
2891 				GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
2892 			if (bio_sectors(bio) > cc->tag_pool_max_sectors)
2893 				dm_accept_partial_bio(bio, cc->tag_pool_max_sectors);
2894 			io->integrity_metadata = mempool_alloc(&cc->tag_pool, GFP_NOIO);
2895 			io->integrity_metadata_from_pool = true;
2896 		}
2897 	}
2898 
2899 	if (crypt_integrity_aead(cc))
2900 		io->ctx.r.req_aead = (struct aead_request *)(io + 1);
2901 	else
2902 		io->ctx.r.req = (struct skcipher_request *)(io + 1);
2903 
2904 	if (bio_data_dir(io->base_bio) == READ) {
2905 		if (kcryptd_io_read(io, GFP_NOWAIT))
2906 			kcryptd_queue_read(io);
2907 	} else
2908 		kcryptd_queue_crypt(io);
2909 
2910 	return DM_MAPIO_SUBMITTED;
2911 }
2912 
2913 static void crypt_status(struct dm_target *ti, status_type_t type,
2914 			 unsigned status_flags, char *result, unsigned maxlen)
2915 {
2916 	struct crypt_config *cc = ti->private;
2917 	unsigned i, sz = 0;
2918 	int num_feature_args = 0;
2919 
2920 	switch (type) {
2921 	case STATUSTYPE_INFO:
2922 		result[0] = '\0';
2923 		break;
2924 
2925 	case STATUSTYPE_TABLE:
2926 		DMEMIT("%s ", cc->cipher_string);
2927 
2928 		if (cc->key_size > 0) {
2929 			if (cc->key_string)
2930 				DMEMIT(":%u:%s", cc->key_size, cc->key_string);
2931 			else
2932 				for (i = 0; i < cc->key_size; i++)
2933 					DMEMIT("%02x", cc->key[i]);
2934 		} else
2935 			DMEMIT("-");
2936 
2937 		DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
2938 				cc->dev->name, (unsigned long long)cc->start);
2939 
2940 		num_feature_args += !!ti->num_discard_bios;
2941 		num_feature_args += test_bit(DM_CRYPT_SAME_CPU, &cc->flags);
2942 		num_feature_args += test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags);
2943 		num_feature_args += cc->sector_size != (1 << SECTOR_SHIFT);
2944 		num_feature_args += test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags);
2945 		if (cc->on_disk_tag_size)
2946 			num_feature_args++;
2947 		if (num_feature_args) {
2948 			DMEMIT(" %d", num_feature_args);
2949 			if (ti->num_discard_bios)
2950 				DMEMIT(" allow_discards");
2951 			if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
2952 				DMEMIT(" same_cpu_crypt");
2953 			if (test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags))
2954 				DMEMIT(" submit_from_crypt_cpus");
2955 			if (cc->on_disk_tag_size)
2956 				DMEMIT(" integrity:%u:%s", cc->on_disk_tag_size, cc->cipher_auth);
2957 			if (cc->sector_size != (1 << SECTOR_SHIFT))
2958 				DMEMIT(" sector_size:%d", cc->sector_size);
2959 			if (test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags))
2960 				DMEMIT(" iv_large_sectors");
2961 		}
2962 
2963 		break;
2964 	}
2965 }
2966 
2967 static void crypt_postsuspend(struct dm_target *ti)
2968 {
2969 	struct crypt_config *cc = ti->private;
2970 
2971 	set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
2972 }
2973 
2974 static int crypt_preresume(struct dm_target *ti)
2975 {
2976 	struct crypt_config *cc = ti->private;
2977 
2978 	if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
2979 		DMERR("aborting resume - crypt key is not set.");
2980 		return -EAGAIN;
2981 	}
2982 
2983 	return 0;
2984 }
2985 
2986 static void crypt_resume(struct dm_target *ti)
2987 {
2988 	struct crypt_config *cc = ti->private;
2989 
2990 	clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
2991 }
2992 
2993 /* Message interface
2994  *	key set <key>
2995  *	key wipe
2996  */
2997 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv,
2998 			 char *result, unsigned maxlen)
2999 {
3000 	struct crypt_config *cc = ti->private;
3001 	int key_size, ret = -EINVAL;
3002 
3003 	if (argc < 2)
3004 		goto error;
3005 
3006 	if (!strcasecmp(argv[0], "key")) {
3007 		if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
3008 			DMWARN("not suspended during key manipulation.");
3009 			return -EINVAL;
3010 		}
3011 		if (argc == 3 && !strcasecmp(argv[1], "set")) {
3012 			/* The key size may not be changed. */
3013 			key_size = get_key_size(&argv[2]);
3014 			if (key_size < 0 || cc->key_size != key_size) {
3015 				memset(argv[2], '0', strlen(argv[2]));
3016 				return -EINVAL;
3017 			}
3018 
3019 			ret = crypt_set_key(cc, argv[2]);
3020 			if (ret)
3021 				return ret;
3022 			if (cc->iv_gen_ops && cc->iv_gen_ops->init)
3023 				ret = cc->iv_gen_ops->init(cc);
3024 			/* wipe the kernel key payload copy */
3025 			if (cc->key_string)
3026 				memset(cc->key, 0, cc->key_size * sizeof(u8));
3027 			return ret;
3028 		}
3029 		if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
3030 			if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
3031 				ret = cc->iv_gen_ops->wipe(cc);
3032 				if (ret)
3033 					return ret;
3034 			}
3035 			return crypt_wipe_key(cc);
3036 		}
3037 	}
3038 
3039 error:
3040 	DMWARN("unrecognised message received.");
3041 	return -EINVAL;
3042 }
3043 
3044 static int crypt_iterate_devices(struct dm_target *ti,
3045 				 iterate_devices_callout_fn fn, void *data)
3046 {
3047 	struct crypt_config *cc = ti->private;
3048 
3049 	return fn(ti, cc->dev, cc->start, ti->len, data);
3050 }
3051 
3052 static void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits)
3053 {
3054 	struct crypt_config *cc = ti->private;
3055 
3056 	/*
3057 	 * Unfortunate constraint that is required to avoid the potential
3058 	 * for exceeding underlying device's max_segments limits -- due to
3059 	 * crypt_alloc_buffer() possibly allocating pages for the encryption
3060 	 * bio that are not as physically contiguous as the original bio.
3061 	 */
3062 	limits->max_segment_size = PAGE_SIZE;
3063 
3064 	limits->logical_block_size =
3065 		max_t(unsigned short, limits->logical_block_size, cc->sector_size);
3066 	limits->physical_block_size =
3067 		max_t(unsigned, limits->physical_block_size, cc->sector_size);
3068 	limits->io_min = max_t(unsigned, limits->io_min, cc->sector_size);
3069 }
3070 
3071 static struct target_type crypt_target = {
3072 	.name   = "crypt",
3073 	.version = {1, 18, 1},
3074 	.module = THIS_MODULE,
3075 	.ctr    = crypt_ctr,
3076 	.dtr    = crypt_dtr,
3077 	.map    = crypt_map,
3078 	.status = crypt_status,
3079 	.postsuspend = crypt_postsuspend,
3080 	.preresume = crypt_preresume,
3081 	.resume = crypt_resume,
3082 	.message = crypt_message,
3083 	.iterate_devices = crypt_iterate_devices,
3084 	.io_hints = crypt_io_hints,
3085 };
3086 
3087 static int __init dm_crypt_init(void)
3088 {
3089 	int r;
3090 
3091 	r = dm_register_target(&crypt_target);
3092 	if (r < 0)
3093 		DMERR("register failed %d", r);
3094 
3095 	return r;
3096 }
3097 
3098 static void __exit dm_crypt_exit(void)
3099 {
3100 	dm_unregister_target(&crypt_target);
3101 }
3102 
3103 module_init(dm_crypt_init);
3104 module_exit(dm_crypt_exit);
3105 
3106 MODULE_AUTHOR("Jana Saout <jana@saout.de>");
3107 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
3108 MODULE_LICENSE("GPL");
3109