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Root/drivers/md/dm-crypt.c

1	/*
2	* Copyright (C) 2003 Christophe Saout <christophe@saout.de>
3	* Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
4	* Copyright (C) 2006-2009 Red Hat, Inc. All rights reserved.
5	*
6	* This file is released under the GPL.
7	*/
8
9	#include <linux/completion.h>
10	#include <linux/err.h>
11	#include <linux/module.h>
12	#include <linux/init.h>
13	#include <linux/kernel.h>
14	#include <linux/bio.h>
15	#include <linux/blkdev.h>
16	#include <linux/mempool.h>
17	#include <linux/slab.h>
18	#include <linux/crypto.h>
19	#include <linux/workqueue.h>
20	#include <linux/backing-dev.h>
21	#include <linux/percpu.h>
22	#include <linux/atomic.h>
23	#include <linux/scatterlist.h>
24	#include <asm/page.h>
25	#include <asm/unaligned.h>
26	#include <crypto/hash.h>
27	#include <crypto/md5.h>
28	#include <crypto/algapi.h>
29
30	#include <linux/device-mapper.h>
31
32	#define DM_MSG_PREFIX "crypt"
33
34	/*
35	* context holding the current state of a multi-part conversion
36	*/
37	struct convert_context {
38	struct completion restart;
39	struct bio *bio_in;
40	struct bio *bio_out;
41	unsigned int offset_in;
42	unsigned int offset_out;
43	unsigned int idx_in;
44	unsigned int idx_out;
45	sector_t cc_sector;
46	atomic_t cc_pending;
47	};
48
49	/*
50	* per bio private data
51	*/
52	struct dm_crypt_io {
53	struct crypt_config *cc;
54	struct bio *base_bio;
55	struct work_struct work;
56
57	struct convert_context ctx;
58
59	atomic_t io_pending;
60	int error;
61	sector_t sector;
62	struct dm_crypt_io *base_io;
63	};
64
65	struct dm_crypt_request {
66	struct convert_context *ctx;
67	struct scatterlist sg_in;
68	struct scatterlist sg_out;
69	sector_t iv_sector;
70	};
71
72	struct crypt_config;
73
74	struct crypt_iv_operations {
75	int (ctr)(struct crypt_config cc, struct dm_target *ti,
76	const char *opts);
77	void (dtr)(struct crypt_config cc);
78	int (init)(struct crypt_config cc);
79	int (wipe)(struct crypt_config cc);
80	int (generator)(struct crypt_config cc, u8 *iv,
81	struct dm_crypt_request *dmreq);
82	int (post)(struct crypt_config cc, u8 *iv,
83	struct dm_crypt_request *dmreq);
84	};
85
86	struct iv_essiv_private {
87	struct crypto_hash *hash_tfm;
88	u8 *salt;
89	};
90
91	struct iv_benbi_private {
92	int shift;
93	};
94
95	#define LMK_SEED_SIZE 64 /* hash + 0 */
96	struct iv_lmk_private {
97	struct crypto_shash *hash_tfm;
98	u8 *seed;
99	};
100
101	/*
102	* Crypt: maps a linear range of a block device
103	* and encrypts / decrypts at the same time.
104	*/
105	enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
106
107	/*
108	* Duplicated per-CPU state for cipher.
109	*/
110	struct crypt_cpu {
111	struct ablkcipher_request *req;
112	};
113
114	/*
115	* The fields in here must be read only after initialization,
116	* changing state should be in crypt_cpu.
117	*/
118	struct crypt_config {
119	struct dm_dev *dev;
120	sector_t start;
121
122	/*
123	* pool for per bio private data, crypto requests and
124	* encryption requeusts/buffer pages
125	*/
126	mempool_t *io_pool;
127	mempool_t *req_pool;
128	mempool_t *page_pool;
129	struct bio_set *bs;
130
131	struct workqueue_struct *io_queue;
132	struct workqueue_struct *crypt_queue;
133
134	char *cipher;
135	char *cipher_string;
136
137	struct crypt_iv_operations *iv_gen_ops;
138	union {
139	struct iv_essiv_private essiv;
140	struct iv_benbi_private benbi;
141	struct iv_lmk_private lmk;
142	} iv_gen_private;
143	sector_t iv_offset;
144	unsigned int iv_size;
145
146	/*
147	* Duplicated per cpu state. Access through
148	* per_cpu_ptr() only.
149	*/
150	struct crypt_cpu __percpu *cpu;
151
152	/* ESSIV: struct crypto_cipher essiv_tfm /
153	void *iv_private;
154	struct crypto_ablkcipher **tfms;
155	unsigned tfms_count;
156
157	/*
158	* Layout of each crypto request:
159	*
160	* struct ablkcipher_request
161	* context
162	* padding
163	* struct dm_crypt_request
164	* padding
165	* IV
166	*
167	* The padding is added so that dm_crypt_request and the IV are
168	* correctly aligned.
169	*/
170	unsigned int dmreq_start;
171
172	unsigned long flags;
173	unsigned int key_size;
174	unsigned int key_parts;
175	u8 key[0];
176	};
177
178	#define MIN_IOS 16
179	#define MIN_POOL_PAGES 32
180
181	static struct kmem_cache *_crypt_io_pool;
182
183	static void clone_init(struct dm_crypt_io , struct bio );
184	static void kcryptd_queue_crypt(struct dm_crypt_io *io);
185	static u8 iv_of_dmreq(struct crypt_config cc, struct dm_crypt_request *dmreq);
186
187	static struct crypt_cpu this_crypt_config(struct crypt_config cc)
188	{
189	return this_cpu_ptr(cc->cpu);
190	}
191
192	/*
193	* Use this to access cipher attributes that are the same for each CPU.
194	*/
195	static struct crypto_ablkcipher any_tfm(struct crypt_config cc)
196	{
197	return cc->tfms[0];
198	}
199
200	/*
201	* Different IV generation algorithms:
202	*
203	* plain: the initial vector is the 32-bit little-endian version of the sector
204	* number, padded with zeros if necessary.
205	*
206	* plain64: the initial vector is the 64-bit little-endian version of the sector
207	* number, padded with zeros if necessary.
208	*
209	* essiv: "encrypted sector\|salt initial vector", the sector number is
210	* encrypted with the bulk cipher using a salt as key. The salt
211	* should be derived from the bulk cipher's key via hashing.
212	*
213	* benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
214	* (needed for LRW-32-AES and possible other narrow block modes)
215	*
216	* null: the initial vector is always zero. Provides compatibility with
217	* obsolete loop_fish2 devices. Do not use for new devices.
218	*
219	* lmk: Compatible implementation of the block chaining mode used
220	* by the Loop-AES block device encryption system
221	* designed by Jari Ruusu. See http://loop-aes.sourceforge.net/
222	* It operates on full 512 byte sectors and uses CBC
223	* with an IV derived from the sector number, the data and
224	* optionally extra IV seed.
225	* This means that after decryption the first block
226	* of sector must be tweaked according to decrypted data.
227	* Loop-AES can use three encryption schemes:
228	* version 1: is plain aes-cbc mode
229	* version 2: uses 64 multikey scheme with lmk IV generator
230	* version 3: the same as version 2 with additional IV seed
231	* (it uses 65 keys, last key is used as IV seed)
232	*
233	* plumb: unimplemented, see:
234	* http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
235	*/
236
237	static int crypt_iv_plain_gen(struct crypt_config cc, u8 iv,
238	struct dm_crypt_request *dmreq)
239	{
240	memset(iv, 0, cc->iv_size);
241	(__le32 )iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff);
242
243	return 0;
244	}
245
246	static int crypt_iv_plain64_gen(struct crypt_config cc, u8 iv,
247	struct dm_crypt_request *dmreq)
248	{
249	memset(iv, 0, cc->iv_size);
250	(__le64 )iv = cpu_to_le64(dmreq->iv_sector);
251
252	return 0;
253	}
254
255	/* Initialise ESSIV - compute salt but no local memory allocations */
256	static int crypt_iv_essiv_init(struct crypt_config *cc)
257	{
258	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
259	struct hash_desc desc;
260	struct scatterlist sg;
261	struct crypto_cipher *essiv_tfm;
262	int err;
263
264	sg_init_one(&sg, cc->key, cc->key_size);
265	desc.tfm = essiv->hash_tfm;
266	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
267
268	err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt);
269	if (err)
270	return err;
271
272	essiv_tfm = cc->iv_private;
273
274	err = crypto_cipher_setkey(essiv_tfm, essiv->salt,
275	crypto_hash_digestsize(essiv->hash_tfm));
276	if (err)
277	return err;
278
279	return 0;
280	}
281
282	/* Wipe salt and reset key derived from volume key */
283	static int crypt_iv_essiv_wipe(struct crypt_config *cc)
284	{
285	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
286	unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm);
287	struct crypto_cipher *essiv_tfm;
288	int r, err = 0;
289
290	memset(essiv->salt, 0, salt_size);
291
292	essiv_tfm = cc->iv_private;
293	r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size);
294	if (r)
295	err = r;
296
297	return err;
298	}
299
300	/* Set up per cpu cipher state */
301	static struct crypto_cipher setup_essiv_cpu(struct crypt_config cc,
302	struct dm_target *ti,
303	u8 *salt, unsigned saltsize)
304	{
305	struct crypto_cipher *essiv_tfm;
306	int err;
307
308	/* Setup the essiv_tfm with the given salt */
309	essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
310	if (IS_ERR(essiv_tfm)) {
311	ti->error = "Error allocating crypto tfm for ESSIV";
312	return essiv_tfm;
313	}
314
315	if (crypto_cipher_blocksize(essiv_tfm) !=
316	crypto_ablkcipher_ivsize(any_tfm(cc))) {
317	ti->error = "Block size of ESSIV cipher does "
318	"not match IV size of block cipher";
319	crypto_free_cipher(essiv_tfm);
320	return ERR_PTR(-EINVAL);
321	}
322
323	err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
324	if (err) {
325	ti->error = "Failed to set key for ESSIV cipher";
326	crypto_free_cipher(essiv_tfm);
327	return ERR_PTR(err);
328	}
329
330	return essiv_tfm;
331	}
332
333	static void crypt_iv_essiv_dtr(struct crypt_config *cc)
334	{
335	struct crypto_cipher *essiv_tfm;
336	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
337
338	crypto_free_hash(essiv->hash_tfm);
339	essiv->hash_tfm = NULL;
340
341	kzfree(essiv->salt);
342	essiv->salt = NULL;
343
344	essiv_tfm = cc->iv_private;
345
346	if (essiv_tfm)
347	crypto_free_cipher(essiv_tfm);
348
349	cc->iv_private = NULL;
350	}
351
352	static int crypt_iv_essiv_ctr(struct crypt_config cc, struct dm_target ti,
353	const char *opts)
354	{
355	struct crypto_cipher *essiv_tfm = NULL;
356	struct crypto_hash *hash_tfm = NULL;
357	u8 *salt = NULL;
358	int err;
359
360	if (!opts) {
361	ti->error = "Digest algorithm missing for ESSIV mode";
362	return -EINVAL;
363	}
364
365	/* Allocate hash algorithm */
366	hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
367	if (IS_ERR(hash_tfm)) {
368	ti->error = "Error initializing ESSIV hash";
369	err = PTR_ERR(hash_tfm);
370	goto bad;
371	}
372
373	salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL);
374	if (!salt) {
375	ti->error = "Error kmallocing salt storage in ESSIV";
376	err = -ENOMEM;
377	goto bad;
378	}
379
380	cc->iv_gen_private.essiv.salt = salt;
381	cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
382
383	essiv_tfm = setup_essiv_cpu(cc, ti, salt,
384	crypto_hash_digestsize(hash_tfm));
385	if (IS_ERR(essiv_tfm)) {
386	crypt_iv_essiv_dtr(cc);
387	return PTR_ERR(essiv_tfm);
388	}
389	cc->iv_private = essiv_tfm;
390
391	return 0;
392
393	bad:
394	if (hash_tfm && !IS_ERR(hash_tfm))
395	crypto_free_hash(hash_tfm);
396	kfree(salt);
397	return err;
398	}
399
400	static int crypt_iv_essiv_gen(struct crypt_config cc, u8 iv,
401	struct dm_crypt_request *dmreq)
402	{
403	struct crypto_cipher *essiv_tfm = cc->iv_private;
404
405	memset(iv, 0, cc->iv_size);
406	(__le64 )iv = cpu_to_le64(dmreq->iv_sector);
407	crypto_cipher_encrypt_one(essiv_tfm, iv, iv);
408
409	return 0;
410	}
411
412	static int crypt_iv_benbi_ctr(struct crypt_config cc, struct dm_target ti,
413	const char *opts)
414	{
415	unsigned bs = crypto_ablkcipher_blocksize(any_tfm(cc));
416	int log = ilog2(bs);
417
418	/* we need to calculate how far we must shift the sector count
419	* to get the cipher block count, we use this shift in _gen */
420
421	if (1 << log != bs) {
422	ti->error = "cypher blocksize is not a power of 2";
423	return -EINVAL;
424	}
425
426	if (log > 9) {
427	ti->error = "cypher blocksize is > 512";
428	return -EINVAL;
429	}
430
431	cc->iv_gen_private.benbi.shift = 9 - log;
432
433	return 0;
434	}
435
436	static void crypt_iv_benbi_dtr(struct crypt_config *cc)
437	{
438	}
439
440	static int crypt_iv_benbi_gen(struct crypt_config cc, u8 iv,
441	struct dm_crypt_request *dmreq)
442	{
443	__be64 val;
444
445	memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
446
447	val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1);
448	put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
449
450	return 0;
451	}
452
453	static int crypt_iv_null_gen(struct crypt_config cc, u8 iv,
454	struct dm_crypt_request *dmreq)
455	{
456	memset(iv, 0, cc->iv_size);
457
458	return 0;
459	}
460
461	static void crypt_iv_lmk_dtr(struct crypt_config *cc)
462	{
463	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
464
465	if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm))
466	crypto_free_shash(lmk->hash_tfm);
467	lmk->hash_tfm = NULL;
468
469	kzfree(lmk->seed);
470	lmk->seed = NULL;
471	}
472
473	static int crypt_iv_lmk_ctr(struct crypt_config cc, struct dm_target ti,
474	const char *opts)
475	{
476	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
477
478	lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0);
479	if (IS_ERR(lmk->hash_tfm)) {
480	ti->error = "Error initializing LMK hash";
481	return PTR_ERR(lmk->hash_tfm);
482	}
483
484	/* No seed in LMK version 2 */
485	if (cc->key_parts == cc->tfms_count) {
486	lmk->seed = NULL;
487	return 0;
488	}
489
490	lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL);
491	if (!lmk->seed) {
492	crypt_iv_lmk_dtr(cc);
493	ti->error = "Error kmallocing seed storage in LMK";
494	return -ENOMEM;
495	}
496
497	return 0;
498	}
499
500	static int crypt_iv_lmk_init(struct crypt_config *cc)
501	{
502	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
503	int subkey_size = cc->key_size / cc->key_parts;
504
505	/* LMK seed is on the position of LMK_KEYS + 1 key */
506	if (lmk->seed)
507	memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size),
508	crypto_shash_digestsize(lmk->hash_tfm));
509
510	return 0;
511	}
512
513	static int crypt_iv_lmk_wipe(struct crypt_config *cc)
514	{
515	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
516
517	if (lmk->seed)
518	memset(lmk->seed, 0, LMK_SEED_SIZE);
519
520	return 0;
521	}
522
523	static int crypt_iv_lmk_one(struct crypt_config cc, u8 iv,
524	struct dm_crypt_request *dmreq,
525	u8 *data)
526	{
527	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
528	struct {
529	struct shash_desc desc;
530	char ctx[crypto_shash_descsize(lmk->hash_tfm)];
531	} sdesc;
532	struct md5_state md5state;
533	u32 buf[4];
534	int i, r;
535
536	sdesc.desc.tfm = lmk->hash_tfm;
537	sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
538
539	r = crypto_shash_init(&sdesc.desc);
540	if (r)
541	return r;
542
543	if (lmk->seed) {
544	r = crypto_shash_update(&sdesc.desc, lmk->seed, LMK_SEED_SIZE);
545	if (r)
546	return r;
547	}
548
549	/* Sector is always 512B, block size 16, add data of blocks 1-31 */
550	r = crypto_shash_update(&sdesc.desc, data + 16, 16 * 31);
551	if (r)
552	return r;
553
554	/* Sector is cropped to 56 bits here */
555	buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF);
556	buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) \| 0x80000000);
557	buf[2] = cpu_to_le32(4024);
558	buf[3] = 0;
559	r = crypto_shash_update(&sdesc.desc, (u8 *)buf, sizeof(buf));
560	if (r)
561	return r;
562
563	/* No MD5 padding here */
564	r = crypto_shash_export(&sdesc.desc, &md5state);
565	if (r)
566	return r;
567
568	for (i = 0; i < MD5_HASH_WORDS; i++)
569	__cpu_to_le32s(&md5state.hash[i]);
570	memcpy(iv, &md5state.hash, cc->iv_size);
571
572	return 0;
573	}
574
575	static int crypt_iv_lmk_gen(struct crypt_config cc, u8 iv,
576	struct dm_crypt_request *dmreq)
577	{
578	u8 *src;
579	int r = 0;
580
581	if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) {
582	src = kmap_atomic(sg_page(&dmreq->sg_in));
583	r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset);
584	kunmap_atomic(src);
585	} else
586	memset(iv, 0, cc->iv_size);
587
588	return r;
589	}
590
591	static int crypt_iv_lmk_post(struct crypt_config cc, u8 iv,
592	struct dm_crypt_request *dmreq)
593	{
594	u8 *dst;
595	int r;
596
597	if (bio_data_dir(dmreq->ctx->bio_in) == WRITE)
598	return 0;
599
600	dst = kmap_atomic(sg_page(&dmreq->sg_out));
601	r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset);
602
603	/* Tweak the first block of plaintext sector */
604	if (!r)
605	crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size);
606
607	kunmap_atomic(dst);
608	return r;
609	}
610
611	static struct crypt_iv_operations crypt_iv_plain_ops = {
612	.generator = crypt_iv_plain_gen
613	};
614
615	static struct crypt_iv_operations crypt_iv_plain64_ops = {
616	.generator = crypt_iv_plain64_gen
617	};
618
619	static struct crypt_iv_operations crypt_iv_essiv_ops = {
620	.ctr = crypt_iv_essiv_ctr,
621	.dtr = crypt_iv_essiv_dtr,
622	.init = crypt_iv_essiv_init,
623	.wipe = crypt_iv_essiv_wipe,
624	.generator = crypt_iv_essiv_gen
625	};
626
627	static struct crypt_iv_operations crypt_iv_benbi_ops = {
628	.ctr = crypt_iv_benbi_ctr,
629	.dtr = crypt_iv_benbi_dtr,
630	.generator = crypt_iv_benbi_gen
631	};
632
633	static struct crypt_iv_operations crypt_iv_null_ops = {
634	.generator = crypt_iv_null_gen
635	};
636
637	static struct crypt_iv_operations crypt_iv_lmk_ops = {
638	.ctr = crypt_iv_lmk_ctr,
639	.dtr = crypt_iv_lmk_dtr,
640	.init = crypt_iv_lmk_init,
641	.wipe = crypt_iv_lmk_wipe,
642	.generator = crypt_iv_lmk_gen,
643	.post = crypt_iv_lmk_post
644	};
645
646	static void crypt_convert_init(struct crypt_config *cc,
647	struct convert_context *ctx,
648	struct bio bio_out, struct bio bio_in,
649	sector_t sector)
650	{
651	ctx->bio_in = bio_in;
652	ctx->bio_out = bio_out;
653	ctx->offset_in = 0;
654	ctx->offset_out = 0;
655	ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
656	ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
657	ctx->cc_sector = sector + cc->iv_offset;
658	init_completion(&ctx->restart);
659	}
660
661	static struct dm_crypt_request dmreq_of_req(struct crypt_config cc,
662	struct ablkcipher_request *req)
663	{
664	return (struct dm_crypt_request )((char )req + cc->dmreq_start);
665	}
666
667	static struct ablkcipher_request req_of_dmreq(struct crypt_config cc,
668	struct dm_crypt_request *dmreq)
669	{
670	return (struct ablkcipher_request )((char )dmreq - cc->dmreq_start);
671	}
672
673	static u8 iv_of_dmreq(struct crypt_config cc,
674	struct dm_crypt_request *dmreq)
675	{
676	return (u8 *)ALIGN((unsigned long)(dmreq + 1),
677	crypto_ablkcipher_alignmask(any_tfm(cc)) + 1);
678	}
679
680	static int crypt_convert_block(struct crypt_config *cc,
681	struct convert_context *ctx,
682	struct ablkcipher_request *req)
683	{
684	struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
685	struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
686	struct dm_crypt_request *dmreq;
687	u8 *iv;
688	int r;
689
690	dmreq = dmreq_of_req(cc, req);
691	iv = iv_of_dmreq(cc, dmreq);
692
693	dmreq->iv_sector = ctx->cc_sector;
694	dmreq->ctx = ctx;
695	sg_init_table(&dmreq->sg_in, 1);
696	sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
697	bv_in->bv_offset + ctx->offset_in);
698
699	sg_init_table(&dmreq->sg_out, 1);
700	sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
701	bv_out->bv_offset + ctx->offset_out);
702
703	ctx->offset_in += 1 << SECTOR_SHIFT;
704	if (ctx->offset_in >= bv_in->bv_len) {
705	ctx->offset_in = 0;
706	ctx->idx_in++;
707	}
708
709	ctx->offset_out += 1 << SECTOR_SHIFT;
710	if (ctx->offset_out >= bv_out->bv_len) {
711	ctx->offset_out = 0;
712	ctx->idx_out++;
713	}
714
715	if (cc->iv_gen_ops) {
716	r = cc->iv_gen_ops->generator(cc, iv, dmreq);
717	if (r < 0)
718	return r;
719	}
720
721	ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
722	1 << SECTOR_SHIFT, iv);
723
724	if (bio_data_dir(ctx->bio_in) == WRITE)
725	r = crypto_ablkcipher_encrypt(req);
726	else
727	r = crypto_ablkcipher_decrypt(req);
728
729	if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
730	r = cc->iv_gen_ops->post(cc, iv, dmreq);
731
732	return r;
733	}
734
735	static void kcryptd_async_done(struct crypto_async_request *async_req,
736	int error);
737
738	static void crypt_alloc_req(struct crypt_config *cc,
739	struct convert_context *ctx)
740	{
741	struct crypt_cpu *this_cc = this_crypt_config(cc);
742	unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1);
743
744	if (!this_cc->req)
745	this_cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
746
747	ablkcipher_request_set_tfm(this_cc->req, cc->tfms[key_index]);
748	ablkcipher_request_set_callback(this_cc->req,
749	CRYPTO_TFM_REQ_MAY_BACKLOG \| CRYPTO_TFM_REQ_MAY_SLEEP,
750	kcryptd_async_done, dmreq_of_req(cc, this_cc->req));
751	}
752
753	/*
754	* Encrypt / decrypt data from one bio to another one (can be the same one)
755	*/
756	static int crypt_convert(struct crypt_config *cc,
757	struct convert_context *ctx)
758	{
759	struct crypt_cpu *this_cc = this_crypt_config(cc);
760	int r;
761
762	atomic_set(&ctx->cc_pending, 1);
763
764	while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
765	ctx->idx_out < ctx->bio_out->bi_vcnt) {
766
767	crypt_alloc_req(cc, ctx);
768
769	atomic_inc(&ctx->cc_pending);
770
771	r = crypt_convert_block(cc, ctx, this_cc->req);
772
773	switch (r) {
774	/* async */
775	case -EBUSY:
776	wait_for_completion(&ctx->restart);
777	INIT_COMPLETION(ctx->restart);
778	/* fall through*/
779	case -EINPROGRESS:
780	this_cc->req = NULL;
781	ctx->cc_sector++;
782	continue;
783
784	/* sync */
785	case 0:
786	atomic_dec(&ctx->cc_pending);
787	ctx->cc_sector++;
788	cond_resched();
789	continue;
790
791	/* error */
792	default:
793	atomic_dec(&ctx->cc_pending);
794	return r;
795	}
796	}
797
798	return 0;
799	}
800
801	static void dm_crypt_bio_destructor(struct bio *bio)
802	{
803	struct dm_crypt_io *io = bio->bi_private;
804	struct crypt_config *cc = io->cc;
805
806	bio_free(bio, cc->bs);
807	}
808
809	/*
810	* Generate a new unfragmented bio with the given size
811	* This should never violate the device limitations
812	* May return a smaller bio when running out of pages, indicated by
813	* *out_of_pages set to 1.
814	*/
815	static struct bio crypt_alloc_buffer(struct dm_crypt_io io, unsigned size,
816	unsigned *out_of_pages)
817	{
818	struct crypt_config *cc = io->cc;
819	struct bio *clone;
820	unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
821	gfp_t gfp_mask = GFP_NOIO \| __GFP_HIGHMEM;
822	unsigned i, len;
823	struct page *page;
824
825	clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
826	if (!clone)
827	return NULL;
828
829	clone_init(io, clone);
830	*out_of_pages = 0;
831
832	for (i = 0; i < nr_iovecs; i++) {
833	page = mempool_alloc(cc->page_pool, gfp_mask);
834	if (!page) {
835	*out_of_pages = 1;
836	break;
837	}
838
839	/*
840	* If additional pages cannot be allocated without waiting,
841	* return a partially-allocated bio. The caller will then try
842	* to allocate more bios while submitting this partial bio.
843	*/
844	gfp_mask = (gfp_mask \| __GFP_NOWARN) & ~__GFP_WAIT;
845
846	len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
847
848	if (!bio_add_page(clone, page, len, 0)) {
849	mempool_free(page, cc->page_pool);
850	break;
851	}
852
853	size -= len;
854	}
855
856	if (!clone->bi_size) {
857	bio_put(clone);
858	return NULL;
859	}
860
861	return clone;
862	}
863
864	static void crypt_free_buffer_pages(struct crypt_config cc, struct bio clone)
865	{
866	unsigned int i;
867	struct bio_vec *bv;
868
869	for (i = 0; i < clone->bi_vcnt; i++) {
870	bv = bio_iovec_idx(clone, i);
871	BUG_ON(!bv->bv_page);
872	mempool_free(bv->bv_page, cc->page_pool);
873	bv->bv_page = NULL;
874	}
875	}
876
877	static struct dm_crypt_io crypt_io_alloc(struct crypt_config cc,
878	struct bio *bio, sector_t sector)
879	{
880	struct dm_crypt_io *io;
881
882	io = mempool_alloc(cc->io_pool, GFP_NOIO);
883	io->cc = cc;
884	io->base_bio = bio;
885	io->sector = sector;
886	io->error = 0;
887	io->base_io = NULL;
888	atomic_set(&io->io_pending, 0);
889
890	return io;
891	}
892
893	static void crypt_inc_pending(struct dm_crypt_io *io)
894	{
895	atomic_inc(&io->io_pending);
896	}
897
898	/*
899	* One of the bios was finished. Check for completion of
900	* the whole request and correctly clean up the buffer.
901	* If base_io is set, wait for the last fragment to complete.
902	*/
903	static void crypt_dec_pending(struct dm_crypt_io *io)
904	{
905	struct crypt_config *cc = io->cc;
906	struct bio *base_bio = io->base_bio;
907	struct dm_crypt_io *base_io = io->base_io;
908	int error = io->error;
909
910	if (!atomic_dec_and_test(&io->io_pending))
911	return;
912
913	mempool_free(io, cc->io_pool);
914
915	if (likely(!base_io))
916	bio_endio(base_bio, error);
917	else {
918	if (error && !base_io->error)
919	base_io->error = error;
920	crypt_dec_pending(base_io);
921	}
922	}
923
924	/*
925	* kcryptd/kcryptd_io:
926	*
927	* Needed because it would be very unwise to do decryption in an
928	* interrupt context.
929	*
930	* kcryptd performs the actual encryption or decryption.
931	*
932	* kcryptd_io performs the IO submission.
933	*
934	* They must be separated as otherwise the final stages could be
935	* starved by new requests which can block in the first stages due
936	* to memory allocation.
937	*
938	* The work is done per CPU global for all dm-crypt instances.
939	* They should not depend on each other and do not block.
940	*/
941	static void crypt_endio(struct bio *clone, int error)
942	{
943	struct dm_crypt_io *io = clone->bi_private;
944	struct crypt_config *cc = io->cc;
945	unsigned rw = bio_data_dir(clone);
946
947	if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
948	error = -EIO;
949
950	/*
951	* free the processed pages
952	*/
953	if (rw == WRITE)
954	crypt_free_buffer_pages(cc, clone);
955
956	bio_put(clone);
957
958	if (rw == READ && !error) {
959	kcryptd_queue_crypt(io);
960	return;
961	}
962
963	if (unlikely(error))
964	io->error = error;
965
966	crypt_dec_pending(io);
967	}
968
969	static void clone_init(struct dm_crypt_io io, struct bio clone)
970	{
971	struct crypt_config *cc = io->cc;
972
973	clone->bi_private = io;
974	clone->bi_end_io = crypt_endio;
975	clone->bi_bdev = cc->dev->bdev;
976	clone->bi_rw = io->base_bio->bi_rw;
977	clone->bi_destructor = dm_crypt_bio_destructor;
978	}
979
980	static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
981	{
982	struct crypt_config *cc = io->cc;
983	struct bio *base_bio = io->base_bio;
984	struct bio *clone;
985
986	/*
987	* The block layer might modify the bvec array, so always
988	* copy the required bvecs because we need the original
989	* one in order to decrypt the whole bio data afterwards.
990	*/
991	clone = bio_alloc_bioset(gfp, bio_segments(base_bio), cc->bs);
992	if (!clone)
993	return 1;
994
995	crypt_inc_pending(io);
996
997	clone_init(io, clone);
998	clone->bi_idx = 0;
999	clone->bi_vcnt = bio_segments(base_bio);
1000	clone->bi_size = base_bio->bi_size;
1001	clone->bi_sector = cc->start + io->sector;
1002	memcpy(clone->bi_io_vec, bio_iovec(base_bio),
1003	sizeof(struct bio_vec) * clone->bi_vcnt);
1004
1005	generic_make_request(clone);
1006	return 0;
1007	}
1008
1009	static void kcryptd_io_write(struct dm_crypt_io *io)
1010	{
1011	struct bio *clone = io->ctx.bio_out;
1012	generic_make_request(clone);
1013	}
1014
1015	static void kcryptd_io(struct work_struct *work)
1016	{
1017	struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1018
1019	if (bio_data_dir(io->base_bio) == READ) {
1020	crypt_inc_pending(io);
1021	if (kcryptd_io_read(io, GFP_NOIO))
1022	io->error = -ENOMEM;
1023	crypt_dec_pending(io);
1024	} else
1025	kcryptd_io_write(io);
1026	}
1027
1028	static void kcryptd_queue_io(struct dm_crypt_io *io)
1029	{
1030	struct crypt_config *cc = io->cc;
1031
1032	INIT_WORK(&io->work, kcryptd_io);
1033	queue_work(cc->io_queue, &io->work);
1034	}
1035
1036	static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
1037	{
1038	struct bio *clone = io->ctx.bio_out;
1039	struct crypt_config *cc = io->cc;
1040
1041	if (unlikely(io->error < 0)) {
1042	crypt_free_buffer_pages(cc, clone);
1043	bio_put(clone);
1044	crypt_dec_pending(io);
1045	return;
1046	}
1047
1048	/* crypt_convert should have filled the clone bio */
1049	BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
1050
1051	clone->bi_sector = cc->start + io->sector;
1052
1053	if (async)
1054	kcryptd_queue_io(io);
1055	else
1056	generic_make_request(clone);
1057	}
1058
1059	static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
1060	{
1061	struct crypt_config *cc = io->cc;
1062	struct bio *clone;
1063	struct dm_crypt_io *new_io;
1064	int crypt_finished;
1065	unsigned out_of_pages = 0;
1066	unsigned remaining = io->base_bio->bi_size;
1067	sector_t sector = io->sector;
1068	int r;
1069
1070	/*
1071	* Prevent io from disappearing until this function completes.
1072	*/
1073	crypt_inc_pending(io);
1074	crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
1075
1076	/*
1077	* The allocated buffers can be smaller than the whole bio,
1078	* so repeat the whole process until all the data can be handled.
1079	*/
1080	while (remaining) {
1081	clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
1082	if (unlikely(!clone)) {
1083	io->error = -ENOMEM;
1084	break;
1085	}
1086
1087	io->ctx.bio_out = clone;
1088	io->ctx.idx_out = 0;
1089
1090	remaining -= clone->bi_size;
1091	sector += bio_sectors(clone);
1092
1093	crypt_inc_pending(io);
1094
1095	r = crypt_convert(cc, &io->ctx);
1096	if (r < 0)
1097	io->error = -EIO;
1098
1099	crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending);
1100
1101	/* Encryption was already finished, submit io now */
1102	if (crypt_finished) {
1103	kcryptd_crypt_write_io_submit(io, 0);
1104
1105	/*
1106	* If there was an error, do not try next fragments.
1107	* For async, error is processed in async handler.
1108	*/
1109	if (unlikely(r < 0))
1110	break;
1111
1112	io->sector = sector;
1113	}
1114
1115	/*
1116	* Out of memory -> run queues
1117	* But don't wait if split was due to the io size restriction
1118	*/
1119	if (unlikely(out_of_pages))
1120	congestion_wait(BLK_RW_ASYNC, HZ/100);
1121
1122	/*
1123	* With async crypto it is unsafe to share the crypto context
1124	* between fragments, so switch to a new dm_crypt_io structure.
1125	*/
1126	if (unlikely(!crypt_finished && remaining)) {
1127	new_io = crypt_io_alloc(io->cc, io->base_bio,
1128	sector);
1129	crypt_inc_pending(new_io);
1130	crypt_convert_init(cc, &new_io->ctx, NULL,
1131	io->base_bio, sector);
1132	new_io->ctx.idx_in = io->ctx.idx_in;
1133	new_io->ctx.offset_in = io->ctx.offset_in;
1134
1135	/*
1136	* Fragments after the first use the base_io
1137	* pending count.
1138	*/
1139	if (!io->base_io)
1140	new_io->base_io = io;
1141	else {
1142	new_io->base_io = io->base_io;
1143	crypt_inc_pending(io->base_io);
1144	crypt_dec_pending(io);
1145	}
1146
1147	io = new_io;
1148	}
1149	}
1150
1151	crypt_dec_pending(io);
1152	}
1153
1154	static void kcryptd_crypt_read_done(struct dm_crypt_io *io)
1155	{
1156	crypt_dec_pending(io);
1157	}
1158
1159	static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
1160	{
1161	struct crypt_config *cc = io->cc;
1162	int r = 0;
1163
1164	crypt_inc_pending(io);
1165
1166	crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
1167	io->sector);
1168
1169	r = crypt_convert(cc, &io->ctx);
1170	if (r < 0)
1171	io->error = -EIO;
1172
1173	if (atomic_dec_and_test(&io->ctx.cc_pending))
1174	kcryptd_crypt_read_done(io);
1175
1176	crypt_dec_pending(io);
1177	}
1178
1179	static void kcryptd_async_done(struct crypto_async_request *async_req,
1180	int error)
1181	{
1182	struct dm_crypt_request *dmreq = async_req->data;
1183	struct convert_context *ctx = dmreq->ctx;
1184	struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
1185	struct crypt_config *cc = io->cc;
1186
1187	if (error == -EINPROGRESS) {
1188	complete(&ctx->restart);
1189	return;
1190	}
1191
1192	if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
1193	error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
1194
1195	if (error < 0)
1196	io->error = -EIO;
1197
1198	mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool);
1199
1200	if (!atomic_dec_and_test(&ctx->cc_pending))
1201	return;
1202
1203	if (bio_data_dir(io->base_bio) == READ)
1204	kcryptd_crypt_read_done(io);
1205	else
1206	kcryptd_crypt_write_io_submit(io, 1);
1207	}
1208
1209	static void kcryptd_crypt(struct work_struct *work)
1210	{
1211	struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
1212
1213	if (bio_data_dir(io->base_bio) == READ)
1214	kcryptd_crypt_read_convert(io);
1215	else
1216	kcryptd_crypt_write_convert(io);
1217	}
1218
1219	static void kcryptd_queue_crypt(struct dm_crypt_io *io)
1220	{
1221	struct crypt_config *cc = io->cc;
1222
1223	INIT_WORK(&io->work, kcryptd_crypt);
1224	queue_work(cc->crypt_queue, &io->work);
1225	}
1226
1227	/*
1228	* Decode key from its hex representation
1229	*/
1230	static int crypt_decode_key(u8 key, char hex, unsigned int size)
1231	{
1232	char buffer[3];
1233	unsigned int i;
1234
1235	buffer[2] = '\0';
1236
1237	for (i = 0; i < size; i++) {
1238	buffer[0] = *hex++;
1239	buffer[1] = *hex++;
1240
1241	if (kstrtou8(buffer, 16, &key[i]))
1242	return -EINVAL;
1243	}
1244
1245	if (*hex != '\0')
1246	return -EINVAL;
1247
1248	return 0;
1249	}
1250
1251	/*
1252	* Encode key into its hex representation
1253	*/
1254	static void crypt_encode_key(char hex, u8 key, unsigned int size)
1255	{
1256	unsigned int i;
1257
1258	for (i = 0; i < size; i++) {
1259	sprintf(hex, "%02x", *key);
1260	hex += 2;
1261	key++;
1262	}
1263	}
1264
1265	static void crypt_free_tfms(struct crypt_config *cc)
1266	{
1267	unsigned i;
1268
1269	if (!cc->tfms)
1270	return;
1271
1272	for (i = 0; i < cc->tfms_count; i++)
1273	if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) {
1274	crypto_free_ablkcipher(cc->tfms[i]);
1275	cc->tfms[i] = NULL;
1276	}
1277
1278	kfree(cc->tfms);
1279	cc->tfms = NULL;
1280	}
1281
1282	static int crypt_alloc_tfms(struct crypt_config cc, char ciphermode)
1283	{
1284	unsigned i;
1285	int err;
1286
1287	cc->tfms = kmalloc(cc->tfms_count * sizeof(struct crypto_ablkcipher *),
1288	GFP_KERNEL);
1289	if (!cc->tfms)
1290	return -ENOMEM;
1291
1292	for (i = 0; i < cc->tfms_count; i++) {
1293	cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0);
1294	if (IS_ERR(cc->tfms[i])) {
1295	err = PTR_ERR(cc->tfms[i]);
1296	crypt_free_tfms(cc);
1297	return err;
1298	}
1299	}
1300
1301	return 0;
1302	}
1303
1304	static int crypt_setkey_allcpus(struct crypt_config *cc)
1305	{
1306	unsigned subkey_size = cc->key_size >> ilog2(cc->tfms_count);
1307	int err = 0, i, r;
1308
1309	for (i = 0; i < cc->tfms_count; i++) {
1310	r = crypto_ablkcipher_setkey(cc->tfms[i],
1311	cc->key + (i * subkey_size),
1312	subkey_size);
1313	if (r)
1314	err = r;
1315	}
1316
1317	return err;
1318	}
1319
1320	static int crypt_set_key(struct crypt_config cc, char key)
1321	{
1322	int r = -EINVAL;
1323	int key_string_len = strlen(key);
1324
1325	/* The key size may not be changed. */
1326	if (cc->key_size != (key_string_len >> 1))
1327	goto out;
1328
1329	/* Hyphen (which gives a key_size of zero) means there is no key. */
1330	if (!cc->key_size && strcmp(key, "-"))
1331	goto out;
1332
1333	if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
1334	goto out;
1335
1336	set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1337
1338	r = crypt_setkey_allcpus(cc);
1339
1340	out:
1341	/* Hex key string not needed after here, so wipe it. */
1342	memset(key, '0', key_string_len);
1343
1344	return r;
1345	}
1346
1347	static int crypt_wipe_key(struct crypt_config *cc)
1348	{
1349	clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
1350	memset(&cc->key, 0, cc->key_size * sizeof(u8));
1351
1352	return crypt_setkey_allcpus(cc);
1353	}
1354
1355	static void crypt_dtr(struct dm_target *ti)
1356	{
1357	struct crypt_config *cc = ti->private;
1358	struct crypt_cpu *cpu_cc;
1359	int cpu;
1360
1361	ti->private = NULL;
1362
1363	if (!cc)
1364	return;
1365
1366	if (cc->io_queue)
1367	destroy_workqueue(cc->io_queue);
1368	if (cc->crypt_queue)
1369	destroy_workqueue(cc->crypt_queue);
1370
1371	if (cc->cpu)
1372	for_each_possible_cpu(cpu) {
1373	cpu_cc = per_cpu_ptr(cc->cpu, cpu);
1374	if (cpu_cc->req)
1375	mempool_free(cpu_cc->req, cc->req_pool);
1376	}
1377
1378	crypt_free_tfms(cc);
1379
1380	if (cc->bs)
1381	bioset_free(cc->bs);
1382
1383	if (cc->page_pool)
1384	mempool_destroy(cc->page_pool);
1385	if (cc->req_pool)
1386	mempool_destroy(cc->req_pool);
1387	if (cc->io_pool)
1388	mempool_destroy(cc->io_pool);
1389
1390	if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1391	cc->iv_gen_ops->dtr(cc);
1392
1393	if (cc->dev)
1394	dm_put_device(ti, cc->dev);
1395
1396	if (cc->cpu)
1397	free_percpu(cc->cpu);
1398
1399	kzfree(cc->cipher);
1400	kzfree(cc->cipher_string);
1401
1402	/* Must zero key material before freeing */
1403	kzfree(cc);
1404	}
1405
1406	static int crypt_ctr_cipher(struct dm_target *ti,
1407	char cipher_in, char key)
1408	{
1409	struct crypt_config *cc = ti->private;
1410	char tmp, cipher, chainmode, ivmode, ivopts, keycount;
1411	char *cipher_api = NULL;
1412	int ret = -EINVAL;
1413	char dummy;
1414
1415	/* Convert to crypto api definition? */
1416	if (strchr(cipher_in, '(')) {
1417	ti->error = "Bad cipher specification";
1418	return -EINVAL;
1419	}
1420
1421	cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
1422	if (!cc->cipher_string)
1423	goto bad_mem;
1424
1425	/*
1426	* Legacy dm-crypt cipher specification
1427	* cipher[:keycount]-mode-iv:ivopts
1428	*/
1429	tmp = cipher_in;
1430	keycount = strsep(&tmp, "-");
1431	cipher = strsep(&keycount, ":");
1432
1433	if (!keycount)
1434	cc->tfms_count = 1;
1435	else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 \|\|
1436	!is_power_of_2(cc->tfms_count)) {
1437	ti->error = "Bad cipher key count specification";
1438	return -EINVAL;
1439	}
1440	cc->key_parts = cc->tfms_count;
1441
1442	cc->cipher = kstrdup(cipher, GFP_KERNEL);
1443	if (!cc->cipher)
1444	goto bad_mem;
1445
1446	chainmode = strsep(&tmp, "-");
1447	ivopts = strsep(&tmp, "-");
1448	ivmode = strsep(&ivopts, ":");
1449
1450	if (tmp)
1451	DMWARN("Ignoring unexpected additional cipher options");
1452
1453	cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)),
1454	__alignof__(struct crypt_cpu));
1455	if (!cc->cpu) {
1456	ti->error = "Cannot allocate per cpu state";
1457	goto bad_mem;
1458	}
1459
1460	/*
1461	* For compatibility with the original dm-crypt mapping format, if
1462	* only the cipher name is supplied, use cbc-plain.
1463	*/
1464	if (!chainmode \|\| (!strcmp(chainmode, "plain") && !ivmode)) {
1465	chainmode = "cbc";
1466	ivmode = "plain";
1467	}
1468
1469	if (strcmp(chainmode, "ecb") && !ivmode) {
1470	ti->error = "IV mechanism required";
1471	return -EINVAL;
1472	}
1473
1474	cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
1475	if (!cipher_api)
1476	goto bad_mem;
1477
1478	ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
1479	"%s(%s)", chainmode, cipher);
1480	if (ret < 0) {
1481	kfree(cipher_api);
1482	goto bad_mem;
1483	}
1484
1485	/* Allocate cipher */
1486	ret = crypt_alloc_tfms(cc, cipher_api);
1487	if (ret < 0) {
1488	ti->error = "Error allocating crypto tfm";
1489	goto bad;
1490	}
1491
1492	/* Initialize and set key */
1493	ret = crypt_set_key(cc, key);
1494	if (ret < 0) {
1495	ti->error = "Error decoding and setting key";
1496	goto bad;
1497	}
1498
1499	/* Initialize IV */
1500	cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc));
1501	if (cc->iv_size)
1502	/* at least a 64 bit sector number should fit in our buffer */
1503	cc->iv_size = max(cc->iv_size,
1504	(unsigned int)(sizeof(u64) / sizeof(u8)));
1505	else if (ivmode) {
1506	DMWARN("Selected cipher does not support IVs");
1507	ivmode = NULL;
1508	}
1509
1510	/* Choose ivmode, see comments at iv code. */
1511	if (ivmode == NULL)
1512	cc->iv_gen_ops = NULL;
1513	else if (strcmp(ivmode, "plain") == 0)
1514	cc->iv_gen_ops = &crypt_iv_plain_ops;
1515	else if (strcmp(ivmode, "plain64") == 0)
1516	cc->iv_gen_ops = &crypt_iv_plain64_ops;
1517	else if (strcmp(ivmode, "essiv") == 0)
1518	cc->iv_gen_ops = &crypt_iv_essiv_ops;
1519	else if (strcmp(ivmode, "benbi") == 0)
1520	cc->iv_gen_ops = &crypt_iv_benbi_ops;
1521	else if (strcmp(ivmode, "null") == 0)
1522	cc->iv_gen_ops = &crypt_iv_null_ops;
1523	else if (strcmp(ivmode, "lmk") == 0) {
1524	cc->iv_gen_ops = &crypt_iv_lmk_ops;
1525	/* Version 2 and 3 is recognised according
1526	* to length of provided multi-key string.
1527	* If present (version 3), last key is used as IV seed.
1528	*/
1529	if (cc->key_size % cc->key_parts)
1530	cc->key_parts++;
1531	} else {
1532	ret = -EINVAL;
1533	ti->error = "Invalid IV mode";
1534	goto bad;
1535	}
1536
1537	/* Allocate IV */
1538	if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
1539	ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
1540	if (ret < 0) {
1541	ti->error = "Error creating IV";
1542	goto bad;
1543	}
1544	}
1545
1546	/* Initialize IV (set keys for ESSIV etc) */
1547	if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
1548	ret = cc->iv_gen_ops->init(cc);
1549	if (ret < 0) {
1550	ti->error = "Error initialising IV";
1551	goto bad;
1552	}
1553	}
1554
1555	ret = 0;
1556	bad:
1557	kfree(cipher_api);
1558	return ret;
1559
1560	bad_mem:
1561	ti->error = "Cannot allocate cipher strings";
1562	return -ENOMEM;
1563	}
1564
1565	/*
1566	* Construct an encryption mapping:
1567	* <cipher> <key> <iv_offset> <dev_path> <start>
1568	*/
1569	static int crypt_ctr(struct dm_target ti, unsigned int argc, char *argv)
1570	{
1571	struct crypt_config *cc;
1572	unsigned int key_size, opt_params;
1573	unsigned long long tmpll;
1574	int ret;
1575	struct dm_arg_set as;
1576	const char *opt_string;
1577	char dummy;
1578
1579	static struct dm_arg _args[] = {
1580	{0, 1, "Invalid number of feature args"},
1581	};
1582
1583	if (argc < 5) {
1584	ti->error = "Not enough arguments";
1585	return -EINVAL;
1586	}
1587
1588	key_size = strlen(argv[1]) >> 1;
1589
1590	cc = kzalloc(sizeof(cc) + key_size sizeof(u8), GFP_KERNEL);
1591	if (!cc) {
1592	ti->error = "Cannot allocate encryption context";
1593	return -ENOMEM;
1594	}
1595	cc->key_size = key_size;
1596
1597	ti->private = cc;
1598	ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
1599	if (ret < 0)
1600	goto bad;
1601
1602	ret = -ENOMEM;
1603	cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1604	if (!cc->io_pool) {
1605	ti->error = "Cannot allocate crypt io mempool";
1606	goto bad;
1607	}
1608
1609	cc->dmreq_start = sizeof(struct ablkcipher_request);
1610	cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc));
1611	cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
1612	cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) &
1613	~(crypto_tfm_ctx_alignment() - 1);
1614
1615	cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1616	sizeof(struct dm_crypt_request) + cc->iv_size);
1617	if (!cc->req_pool) {
1618	ti->error = "Cannot allocate crypt request mempool";
1619	goto bad;
1620	}
1621
1622	cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1623	if (!cc->page_pool) {
1624	ti->error = "Cannot allocate page mempool";
1625	goto bad;
1626	}
1627
1628	cc->bs = bioset_create(MIN_IOS, 0);
1629	if (!cc->bs) {
1630	ti->error = "Cannot allocate crypt bioset";
1631	goto bad;
1632	}
1633
1634	ret = -EINVAL;
1635	if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) {
1636	ti->error = "Invalid iv_offset sector";
1637	goto bad;
1638	}
1639	cc->iv_offset = tmpll;
1640
1641	if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
1642	ti->error = "Device lookup failed";
1643	goto bad;
1644	}
1645
1646	if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
1647	ti->error = "Invalid device sector";
1648	goto bad;
1649	}
1650	cc->start = tmpll;
1651
1652	argv += 5;
1653	argc -= 5;
1654
1655	/* Optional parameters */
1656	if (argc) {
1657	as.argc = argc;
1658	as.argv = argv;
1659
1660	ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1661	if (ret)
1662	goto bad;
1663
1664	opt_string = dm_shift_arg(&as);
1665
1666	if (opt_params == 1 && opt_string &&
1667	!strcasecmp(opt_string, "allow_discards"))
1668	ti->num_discard_requests = 1;
1669	else if (opt_params) {
1670	ret = -EINVAL;
1671	ti->error = "Invalid feature arguments";
1672	goto bad;
1673	}
1674	}
1675
1676	ret = -ENOMEM;
1677	cc->io_queue = alloc_workqueue("kcryptd_io",
1678	WQ_NON_REENTRANT\|
1679	WQ_MEM_RECLAIM,
1680	1);
1681	if (!cc->io_queue) {
1682	ti->error = "Couldn't create kcryptd io queue";
1683	goto bad;
1684	}
1685
1686	cc->crypt_queue = alloc_workqueue("kcryptd",
1687	WQ_NON_REENTRANT\|
1688	WQ_CPU_INTENSIVE\|
1689	WQ_MEM_RECLAIM,
1690	1);
1691	if (!cc->crypt_queue) {
1692	ti->error = "Couldn't create kcryptd queue";
1693	goto bad;
1694	}
1695
1696	ti->num_flush_requests = 1;
1697	ti->discard_zeroes_data_unsupported = true;
1698
1699	return 0;
1700
1701	bad:
1702	crypt_dtr(ti);
1703	return ret;
1704	}
1705
1706	static int crypt_map(struct dm_target ti, struct bio bio,
1707	union map_info *map_context)
1708	{
1709	struct dm_crypt_io *io;
1710	struct crypt_config *cc = ti->private;
1711
1712	/*
1713	* If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues.
1714	* - for REQ_FLUSH device-mapper core ensures that no IO is in-flight
1715	* - for REQ_DISCARD caller must use flush if IO ordering matters
1716	*/
1717	if (unlikely(bio->bi_rw & (REQ_FLUSH \| REQ_DISCARD))) {
1718	bio->bi_bdev = cc->dev->bdev;
1719	if (bio_sectors(bio))
1720	bio->bi_sector = cc->start + dm_target_offset(ti, bio->bi_sector);
1721	return DM_MAPIO_REMAPPED;
1722	}
1723
1724	io = crypt_io_alloc(cc, bio, dm_target_offset(ti, bio->bi_sector));
1725
1726	if (bio_data_dir(io->base_bio) == READ) {
1727	if (kcryptd_io_read(io, GFP_NOWAIT))
1728	kcryptd_queue_io(io);
1729	} else
1730	kcryptd_queue_crypt(io);
1731
1732	return DM_MAPIO_SUBMITTED;
1733	}
1734
1735	static int crypt_status(struct dm_target *ti, status_type_t type,
1736	unsigned status_flags, char *result, unsigned maxlen)
1737	{
1738	struct crypt_config *cc = ti->private;
1739	unsigned int sz = 0;
1740
1741	switch (type) {
1742	case STATUSTYPE_INFO:
1743	result[0] = '\0';
1744	break;
1745
1746	case STATUSTYPE_TABLE:
1747	DMEMIT("%s ", cc->cipher_string);
1748
1749	if (cc->key_size > 0) {
1750	if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1751	return -ENOMEM;
1752
1753	crypt_encode_key(result + sz, cc->key, cc->key_size);
1754	sz += cc->key_size << 1;
1755	} else {
1756	if (sz >= maxlen)
1757	return -ENOMEM;
1758	result[sz++] = '-';
1759	}
1760
1761	DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1762	cc->dev->name, (unsigned long long)cc->start);
1763
1764	if (ti->num_discard_requests)
1765	DMEMIT(" 1 allow_discards");
1766
1767	break;
1768	}
1769	return 0;
1770	}
1771
1772	static void crypt_postsuspend(struct dm_target *ti)
1773	{
1774	struct crypt_config *cc = ti->private;
1775
1776	set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1777	}
1778
1779	static int crypt_preresume(struct dm_target *ti)
1780	{
1781	struct crypt_config *cc = ti->private;
1782
1783	if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1784	DMERR("aborting resume - crypt key is not set.");
1785	return -EAGAIN;
1786	}
1787
1788	return 0;
1789	}
1790
1791	static void crypt_resume(struct dm_target *ti)
1792	{
1793	struct crypt_config *cc = ti->private;
1794
1795	clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1796	}
1797
1798	/* Message interface
1799	* key set <key>
1800	* key wipe
1801	*/
1802	static int crypt_message(struct dm_target ti, unsigned argc, char *argv)
1803	{
1804	struct crypt_config *cc = ti->private;
1805	int ret = -EINVAL;
1806
1807	if (argc < 2)
1808	goto error;
1809
1810	if (!strcasecmp(argv[0], "key")) {
1811	if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1812	DMWARN("not suspended during key manipulation.");
1813	return -EINVAL;
1814	}
1815	if (argc == 3 && !strcasecmp(argv[1], "set")) {
1816	ret = crypt_set_key(cc, argv[2]);
1817	if (ret)
1818	return ret;
1819	if (cc->iv_gen_ops && cc->iv_gen_ops->init)
1820	ret = cc->iv_gen_ops->init(cc);
1821	return ret;
1822	}
1823	if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
1824	if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
1825	ret = cc->iv_gen_ops->wipe(cc);
1826	if (ret)
1827	return ret;
1828	}
1829	return crypt_wipe_key(cc);
1830	}
1831	}
1832
1833	error:
1834	DMWARN("unrecognised message received.");
1835	return -EINVAL;
1836	}
1837
1838	static int crypt_merge(struct dm_target ti, struct bvec_merge_data bvm,
1839	struct bio_vec *biovec, int max_size)
1840	{
1841	struct crypt_config *cc = ti->private;
1842	struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1843
1844	if (!q->merge_bvec_fn)
1845	return max_size;
1846
1847	bvm->bi_bdev = cc->dev->bdev;
1848	bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
1849
1850	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1851	}
1852
1853	static int crypt_iterate_devices(struct dm_target *ti,
1854	iterate_devices_callout_fn fn, void *data)
1855	{
1856	struct crypt_config *cc = ti->private;
1857
1858	return fn(ti, cc->dev, cc->start, ti->len, data);
1859	}
1860
1861	static struct target_type crypt_target = {
1862	.name = "crypt",
1863	.version = {1, 11, 0},
1864	.module = THIS_MODULE,
1865	.ctr = crypt_ctr,
1866	.dtr = crypt_dtr,
1867	.map = crypt_map,
1868	.status = crypt_status,
1869	.postsuspend = crypt_postsuspend,
1870	.preresume = crypt_preresume,
1871	.resume = crypt_resume,
1872	.message = crypt_message,
1873	.merge = crypt_merge,
1874	.iterate_devices = crypt_iterate_devices,
1875	};
1876
1877	static int __init dm_crypt_init(void)
1878	{
1879	int r;
1880
1881	_crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1882	if (!_crypt_io_pool)
1883	return -ENOMEM;
1884
1885	r = dm_register_target(&crypt_target);
1886	if (r < 0) {
1887	DMERR("register failed %d", r);
1888	kmem_cache_destroy(_crypt_io_pool);
1889	}
1890
1891	return r;
1892	}
1893
1894	static void __exit dm_crypt_exit(void)
1895	{
1896	dm_unregister_target(&crypt_target);
1897	kmem_cache_destroy(_crypt_io_pool);
1898	}
1899
1900	module_init(dm_crypt_init);
1901	module_exit(dm_crypt_exit);
1902
1903	MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1904	MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1905	MODULE_LICENSE("GPL");
1906

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