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[BLOCK] cryptoloop: Use block ciphers where applicable
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / md / dm-crypt.c
CommitLineData
1da177e4
LT		 1/*
2 * Copyright (C) 2003 Christophe Saout <christophe@saout.de>
3 * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
4 *
5 * This file is released under the GPL.
6 */
7
8#include <linux/module.h>
9#include <linux/init.h>
10#include <linux/kernel.h>
11#include <linux/bio.h>
12#include <linux/blkdev.h>
13#include <linux/mempool.h>
14#include <linux/slab.h>
15#include <linux/crypto.h>
16#include <linux/workqueue.h>
17#include <asm/atomic.h>
378f058c 18#include <linux/scatterlist.h>
1da177e4
LT		 19#include <asm/page.h>
20
21#include "dm.h"
22
72d94861 23#define DM_MSG_PREFIX "crypt"
1da177e4
LT		 24
25/*
26 * per bio private data
27 */
28struct crypt_io {
29 struct dm_target *target;
30 struct bio *bio;
31 struct bio *first_clone;
32 struct work_struct work;
33 atomic_t pending;
34 int error;
35};
36
37/*
38 * context holding the current state of a multi-part conversion
39 */
40struct convert_context {
41 struct bio *bio_in;
42 struct bio *bio_out;
43 unsigned int offset_in;
44 unsigned int offset_out;
45 unsigned int idx_in;
46 unsigned int idx_out;
47 sector_t sector;
48 int write;
49};
50
51struct crypt_config;
52
53struct crypt_iv_operations {
54 int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
55 const char *opts);
56 void (*dtr)(struct crypt_config *cc);
57 const char *(*status)(struct crypt_config *cc);
58 int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
59};
60
61/*
62 * Crypt: maps a linear range of a block device
63 * and encrypts / decrypts at the same time.
64 */
65struct crypt_config {
66 struct dm_dev *dev;
67 sector_t start;
68
69 /*
70 * pool for per bio private data and
71 * for encryption buffer pages
72 */
73 mempool_t *io_pool;
74 mempool_t *page_pool;
75
76 /*
77 * crypto related data
78 */
79 struct crypt_iv_operations *iv_gen_ops;
80 char *iv_mode;
81 void *iv_gen_private;
82 sector_t iv_offset;
83 unsigned int iv_size;
84
85 struct crypto_tfm *tfm;
86 unsigned int key_size;
87 u8 key[0];
88};
89
90#define MIN_IOS 256
91#define MIN_POOL_PAGES 32
92#define MIN_BIO_PAGES 8
93
94static kmem_cache_t *_crypt_io_pool;
95
1da177e4
LT		 96/*
97 * Different IV generation algorithms:
98 *
99 * plain: the initial vector is the 32-bit low-endian version of the sector
100 * number, padded with zeros if neccessary.
101 *
102 * ess_iv: "encrypted sector|salt initial vector", the sector number is
103 * encrypted with the bulk cipher using a salt as key. The salt
104 * should be derived from the bulk cipher's key via hashing.
105 *
106 * plumb: unimplemented, see:
107 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
108 */
109
110static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
111{
112 memset(iv, 0, cc->iv_size);
113 *(u32 *)iv = cpu_to_le32(sector & 0xffffffff);
114
115 return 0;
116}
117
118static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
119 const char *opts)
120{
121 struct crypto_tfm *essiv_tfm;
122 struct crypto_tfm *hash_tfm;
123 struct scatterlist sg;
124 unsigned int saltsize;
125 u8 *salt;
126
127 if (opts == NULL) {
72d94861 128 ti->error = "Digest algorithm missing for ESSIV mode";
1da177e4
LT		 129 return -EINVAL;
130 }
131
132 /* Hash the cipher key with the given hash algorithm */
eb6f1160 133 hash_tfm = crypto_alloc_tfm(opts, CRYPTO_TFM_REQ_MAY_SLEEP);
1da177e4 134 if (hash_tfm == NULL) {
72d94861 135 ti->error = "Error initializing ESSIV hash";
1da177e4
LT		 136 return -EINVAL;
137 }
138
139 if (crypto_tfm_alg_type(hash_tfm) != CRYPTO_ALG_TYPE_DIGEST) {
72d94861 140 ti->error = "Expected digest algorithm for ESSIV hash";
1da177e4
LT		 141 crypto_free_tfm(hash_tfm);
142 return -EINVAL;
143 }
144
145 saltsize = crypto_tfm_alg_digestsize(hash_tfm);
146 salt = kmalloc(saltsize, GFP_KERNEL);
147 if (salt == NULL) {
72d94861 148 ti->error = "Error kmallocing salt storage in ESSIV";
1da177e4
LT		 149 crypto_free_tfm(hash_tfm);
150 return -ENOMEM;
151 }
152
378f058c 153 sg_set_buf(&sg, cc->key, cc->key_size);
1da177e4
LT		 154 crypto_digest_digest(hash_tfm, &sg, 1, salt);
155 crypto_free_tfm(hash_tfm);
156
157 /* Setup the essiv_tfm with the given salt */
158 essiv_tfm = crypto_alloc_tfm(crypto_tfm_alg_name(cc->tfm),
eb6f1160
HX		 159 CRYPTO_TFM_MODE_ECB |
160 CRYPTO_TFM_REQ_MAY_SLEEP);
1da177e4 161 if (essiv_tfm == NULL) {
72d94861 162 ti->error = "Error allocating crypto tfm for ESSIV";
1da177e4
LT		 163 kfree(salt);
164 return -EINVAL;
165 }
166 if (crypto_tfm_alg_blocksize(essiv_tfm)
167 != crypto_tfm_alg_ivsize(cc->tfm)) {
72d94861 168 ti->error = "Block size of ESSIV cipher does "
1da177e4
LT		 169 "not match IV size of block cipher";
170 crypto_free_tfm(essiv_tfm);
171 kfree(salt);
172 return -EINVAL;
173 }
174 if (crypto_cipher_setkey(essiv_tfm, salt, saltsize) < 0) {
72d94861 175 ti->error = "Failed to set key for ESSIV cipher";
1da177e4
LT		 176 crypto_free_tfm(essiv_tfm);
177 kfree(salt);
178 return -EINVAL;
179 }
180 kfree(salt);
181
182 cc->iv_gen_private = (void *)essiv_tfm;
183 return 0;
184}
185
186static void crypt_iv_essiv_dtr(struct crypt_config *cc)
187{
188 crypto_free_tfm((struct crypto_tfm *)cc->iv_gen_private);
189 cc->iv_gen_private = NULL;
190}
191
192static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
193{
378f058c 194 struct scatterlist sg;
1da177e4
LT		 195
196 memset(iv, 0, cc->iv_size);
197 *(u64 *)iv = cpu_to_le64(sector);
198
378f058c 199 sg_set_buf(&sg, iv, cc->iv_size);
1da177e4
LT		 200 crypto_cipher_encrypt((struct crypto_tfm *)cc->iv_gen_private,
201 &sg, &sg, cc->iv_size);
202
203 return 0;
204}
205
206static struct crypt_iv_operations crypt_iv_plain_ops = {
207 .generator = crypt_iv_plain_gen
208};
209
210static struct crypt_iv_operations crypt_iv_essiv_ops = {
211 .ctr = crypt_iv_essiv_ctr,
212 .dtr = crypt_iv_essiv_dtr,
213 .generator = crypt_iv_essiv_gen
214};
215
216
858119e1 217static int
1da177e4
LT		 218crypt_convert_scatterlist(struct crypt_config *cc, struct scatterlist *out,
219 struct scatterlist *in, unsigned int length,
220 int write, sector_t sector)
221{
222 u8 iv[cc->iv_size];
223 int r;
224
225 if (cc->iv_gen_ops) {
226 r = cc->iv_gen_ops->generator(cc, iv, sector);
227 if (r < 0)
228 return r;
229
230 if (write)
231 r = crypto_cipher_encrypt_iv(cc->tfm, out, in, length, iv);
232 else
233 r = crypto_cipher_decrypt_iv(cc->tfm, out, in, length, iv);
234 } else {
235 if (write)
236 r = crypto_cipher_encrypt(cc->tfm, out, in, length);
237 else
238 r = crypto_cipher_decrypt(cc->tfm, out, in, length);
239 }
240
241 return r;
242}
243
244static void
245crypt_convert_init(struct crypt_config *cc, struct convert_context *ctx,
246 struct bio *bio_out, struct bio *bio_in,
247 sector_t sector, int write)
248{
249 ctx->bio_in = bio_in;
250 ctx->bio_out = bio_out;
251 ctx->offset_in = 0;
252 ctx->offset_out = 0;
253 ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
254 ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
255 ctx->sector = sector + cc->iv_offset;
256 ctx->write = write;
257}
258
259/*
260 * Encrypt / decrypt data from one bio to another one (can be the same one)
261 */
262static int crypt_convert(struct crypt_config *cc,
263 struct convert_context *ctx)
264{
265 int r = 0;
266
267 while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
268 ctx->idx_out < ctx->bio_out->bi_vcnt) {
269 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
270 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
271 struct scatterlist sg_in = {
272 .page = bv_in->bv_page,
273 .offset = bv_in->bv_offset + ctx->offset_in,
274 .length = 1 << SECTOR_SHIFT
275 };
276 struct scatterlist sg_out = {
277 .page = bv_out->bv_page,
278 .offset = bv_out->bv_offset + ctx->offset_out,
279 .length = 1 << SECTOR_SHIFT
280 };
281
282 ctx->offset_in += sg_in.length;
283 if (ctx->offset_in >= bv_in->bv_len) {
284 ctx->offset_in = 0;
285 ctx->idx_in++;
286 }
287
288 ctx->offset_out += sg_out.length;
289 if (ctx->offset_out >= bv_out->bv_len) {
290 ctx->offset_out = 0;
291 ctx->idx_out++;
292 }
293
294 r = crypt_convert_scatterlist(cc, &sg_out, &sg_in, sg_in.length,
295 ctx->write, ctx->sector);
296 if (r < 0)
297 break;
298
299 ctx->sector++;
300 }
301
302 return r;
303}
304
305/*
306 * Generate a new unfragmented bio with the given size
307 * This should never violate the device limitations
308 * May return a smaller bio when running out of pages
309 */
310static struct bio *
311crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
312 struct bio *base_bio, unsigned int *bio_vec_idx)
313{
314 struct bio *bio;
315 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
b4e3ca1a 316 gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
1da177e4
LT		 317 unsigned int i;
318
319 /*
bd53b714
NP		 320 * Use __GFP_NOMEMALLOC to tell the VM to act less aggressively and
321 * to fail earlier. This is not necessary but increases throughput.
1da177e4
LT		 322 * FIXME: Is this really intelligent?
323 */
1da177e4 324 if (base_bio)
bd53b714 325 bio = bio_clone(base_bio, GFP_NOIO|__GFP_NOMEMALLOC);
1da177e4 326 else
bd53b714
NP		 327 bio = bio_alloc(GFP_NOIO|__GFP_NOMEMALLOC, nr_iovecs);
328 if (!bio)
1da177e4 329 return NULL;
1da177e4
LT		 330
331 /* if the last bio was not complete, continue where that one ended */
332 bio->bi_idx = *bio_vec_idx;
333 bio->bi_vcnt = *bio_vec_idx;
334 bio->bi_size = 0;
335 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
336
337 /* bio->bi_idx pages have already been allocated */
338 size -= bio->bi_idx * PAGE_SIZE;
339
340 for(i = bio->bi_idx; i < nr_iovecs; i++) {
341 struct bio_vec *bv = bio_iovec_idx(bio, i);
342
343 bv->bv_page = mempool_alloc(cc->page_pool, gfp_mask);
344 if (!bv->bv_page)
345 break;
346
347 /*
348 * if additional pages cannot be allocated without waiting,
349 * return a partially allocated bio, the caller will then try
350 * to allocate additional bios while submitting this partial bio
351 */
352 if ((i - bio->bi_idx) == (MIN_BIO_PAGES - 1))
353 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
354
355 bv->bv_offset = 0;
356 if (size > PAGE_SIZE)
357 bv->bv_len = PAGE_SIZE;
358 else
359 bv->bv_len = size;
360
361 bio->bi_size += bv->bv_len;
362 bio->bi_vcnt++;
363 size -= bv->bv_len;
364 }
365
1da177e4
LT		 366 if (!bio->bi_size) {
367 bio_put(bio);
368 return NULL;
369 }
370
371 /*
372 * Remember the last bio_vec allocated to be able
373 * to correctly continue after the splitting.
374 */
375 *bio_vec_idx = bio->bi_vcnt;
376
377 return bio;
378}
379
380static void crypt_free_buffer_pages(struct crypt_config *cc,
381 struct bio *bio, unsigned int bytes)
382{
383 unsigned int i, start, end;
384 struct bio_vec *bv;
385
386 /*
387 * This is ugly, but Jens Axboe thinks that using bi_idx in the
388 * endio function is too dangerous at the moment, so I calculate the
389 * correct position using bi_vcnt and bi_size.
390 * The bv_offset and bv_len fields might already be modified but we
391 * know that we always allocated whole pages.
392 * A fix to the bi_idx issue in the kernel is in the works, so
393 * we will hopefully be able to revert to the cleaner solution soon.
394 */
395 i = bio->bi_vcnt - 1;
396 bv = bio_iovec_idx(bio, i);
397 end = (i << PAGE_SHIFT) + (bv->bv_offset + bv->bv_len) - bio->bi_size;
398 start = end - bytes;
399
400 start >>= PAGE_SHIFT;
401 if (!bio->bi_size)
402 end = bio->bi_vcnt;
403 else
404 end >>= PAGE_SHIFT;
405
406 for(i = start; i < end; i++) {
407 bv = bio_iovec_idx(bio, i);
408 BUG_ON(!bv->bv_page);
409 mempool_free(bv->bv_page, cc->page_pool);
410 bv->bv_page = NULL;
411 }
412}
413
414/*
415 * One of the bios was finished. Check for completion of
416 * the whole request and correctly clean up the buffer.
417 */
418static void dec_pending(struct crypt_io *io, int error)
419{
420 struct crypt_config *cc = (struct crypt_config *) io->target->private;
421
422 if (error < 0)
423 io->error = error;
424
425 if (!atomic_dec_and_test(&io->pending))
426 return;
427
428 if (io->first_clone)
429 bio_put(io->first_clone);
430
431 bio_endio(io->bio, io->bio->bi_size, io->error);
432
433 mempool_free(io, cc->io_pool);
434}
435
436/*
437 * kcryptd:
438 *
439 * Needed because it would be very unwise to do decryption in an
440 * interrupt context, so bios returning from read requests get
441 * queued here.
442 */
443static struct workqueue_struct *_kcryptd_workqueue;
444
445static void kcryptd_do_work(void *data)
446{
447 struct crypt_io *io = (struct crypt_io *) data;
448 struct crypt_config *cc = (struct crypt_config *) io->target->private;
449 struct convert_context ctx;
450 int r;
451
452 crypt_convert_init(cc, &ctx, io->bio, io->bio,
453 io->bio->bi_sector - io->target->begin, 0);
454 r = crypt_convert(cc, &ctx);
455
456 dec_pending(io, r);
457}
458
459static void kcryptd_queue_io(struct crypt_io *io)
460{
461 INIT_WORK(&io->work, kcryptd_do_work, io);
462 queue_work(_kcryptd_workqueue, &io->work);
463}
464
465/*
466 * Decode key from its hex representation
467 */
468static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
469{
470 char buffer[3];
471 char *endp;
472 unsigned int i;
473
474 buffer[2] = '\0';
475
476 for(i = 0; i < size; i++) {
477 buffer[0] = *hex++;
478 buffer[1] = *hex++;
479
480 key[i] = (u8)simple_strtoul(buffer, &endp, 16);
481
482 if (endp != &buffer[2])
483 return -EINVAL;
484 }
485
486 if (*hex != '\0')
487 return -EINVAL;
488
489 return 0;
490}
491
492/*
493 * Encode key into its hex representation
494 */
495static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
496{
497 unsigned int i;
498
499 for(i = 0; i < size; i++) {
500 sprintf(hex, "%02x", *key);
501 hex += 2;
502 key++;
503 }
504}
505
506/*
507 * Construct an encryption mapping:
508 * <cipher> <key> <iv_offset> <dev_path> <start>
509 */
510static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
511{
512 struct crypt_config *cc;
513 struct crypto_tfm *tfm;
514 char *tmp;
515 char *cipher;
516 char *chainmode;
517 char *ivmode;
518 char *ivopts;
519 unsigned int crypto_flags;
520 unsigned int key_size;
4ee218cd 521 unsigned long long tmpll;
1da177e4
LT		 522
523 if (argc != 5) {
72d94861 524 ti->error = "Not enough arguments";
1da177e4
LT		 525 return -EINVAL;
526 }
527
528 tmp = argv[0];
529 cipher = strsep(&tmp, "-");
530 chainmode = strsep(&tmp, "-");
531 ivopts = strsep(&tmp, "-");
532 ivmode = strsep(&ivopts, ":");
533
534 if (tmp)
72d94861 535 DMWARN("Unexpected additional cipher options");
1da177e4
LT		 536
537 key_size = strlen(argv[1]) >> 1;
538
539 cc = kmalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
540 if (cc == NULL) {
541 ti->error =
72d94861 542 "Cannot allocate transparent encryption context";
1da177e4
LT		 543 return -ENOMEM;
544 }
545
546 cc->key_size = key_size;
547 if ((!key_size && strcmp(argv[1], "-") != 0) ||
548 (key_size && crypt_decode_key(cc->key, argv[1], key_size) < 0)) {
72d94861 549 ti->error = "Error decoding key";
1da177e4
LT		 550 goto bad1;
551 }
552
553 /* Compatiblity mode for old dm-crypt cipher strings */
554 if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
555 chainmode = "cbc";
556 ivmode = "plain";
557 }
558
559 /* Choose crypto_flags according to chainmode */
560 if (strcmp(chainmode, "cbc") == 0)
561 crypto_flags = CRYPTO_TFM_MODE_CBC;
562 else if (strcmp(chainmode, "ecb") == 0)
563 crypto_flags = CRYPTO_TFM_MODE_ECB;
564 else {
72d94861 565 ti->error = "Unknown chaining mode";
1da177e4
LT		 566 goto bad1;
567 }
568
569 if (crypto_flags != CRYPTO_TFM_MODE_ECB && !ivmode) {
72d94861 570 ti->error = "This chaining mode requires an IV mechanism";
1da177e4
LT		 571 goto bad1;
572 }
573
eb6f1160 574 tfm = crypto_alloc_tfm(cipher, crypto_flags | CRYPTO_TFM_REQ_MAY_SLEEP);
1da177e4 575 if (!tfm) {
72d94861 576 ti->error = "Error allocating crypto tfm";
1da177e4
LT		 577 goto bad1;
578 }
579 if (crypto_tfm_alg_type(tfm) != CRYPTO_ALG_TYPE_CIPHER) {
72d94861 580 ti->error = "Expected cipher algorithm";
1da177e4
LT		 581 goto bad2;
582 }
583
584 cc->tfm = tfm;
585
586 /*
587 * Choose ivmode. Valid modes: "plain", "essiv:<esshash>".
588 * See comments at iv code
589 */
590
591 if (ivmode == NULL)
592 cc->iv_gen_ops = NULL;
593 else if (strcmp(ivmode, "plain") == 0)
594 cc->iv_gen_ops = &crypt_iv_plain_ops;
595 else if (strcmp(ivmode, "essiv") == 0)
596 cc->iv_gen_ops = &crypt_iv_essiv_ops;
597 else {
72d94861 598 ti->error = "Invalid IV mode";
1da177e4
LT		 599 goto bad2;
600 }
601
602 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr &&
603 cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
604 goto bad2;
605
606 if (tfm->crt_cipher.cit_decrypt_iv && tfm->crt_cipher.cit_encrypt_iv)
607 /* at least a 64 bit sector number should fit in our buffer */
608 cc->iv_size = max(crypto_tfm_alg_ivsize(tfm),
609 (unsigned int)(sizeof(u64) / sizeof(u8)));
610 else {
611 cc->iv_size = 0;
612 if (cc->iv_gen_ops) {
72d94861 613 DMWARN("Selected cipher does not support IVs");
1da177e4
LT		 614 if (cc->iv_gen_ops->dtr)
615 cc->iv_gen_ops->dtr(cc);
616 cc->iv_gen_ops = NULL;
617 }
618 }
619
93d2341c 620 cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1da177e4 621 if (!cc->io_pool) {
72d94861 622 ti->error = "Cannot allocate crypt io mempool";
1da177e4
LT		 623 goto bad3;
624 }
625
a19b27ce 626 cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1da177e4 627 if (!cc->page_pool) {
72d94861 628 ti->error = "Cannot allocate page mempool";
1da177e4
LT		 629 goto bad4;
630 }
631
632 if (tfm->crt_cipher.cit_setkey(tfm, cc->key, key_size) < 0) {
72d94861 633 ti->error = "Error setting key";
1da177e4
LT		 634 goto bad5;
635 }
636
4ee218cd 637 if (sscanf(argv[2], "%llu", &tmpll) != 1) {
72d94861 638 ti->error = "Invalid iv_offset sector";
1da177e4
LT		 639 goto bad5;
640 }
4ee218cd 641 cc->iv_offset = tmpll;
1da177e4 642
4ee218cd 643 if (sscanf(argv[4], "%llu", &tmpll) != 1) {
72d94861 644 ti->error = "Invalid device sector";
1da177e4
LT		 645 goto bad5;
646 }
4ee218cd 647 cc->start = tmpll;
1da177e4
LT		 648
649 if (dm_get_device(ti, argv[3], cc->start, ti->len,
650 dm_table_get_mode(ti->table), &cc->dev)) {
72d94861 651 ti->error = "Device lookup failed";
1da177e4
LT		 652 goto bad5;
653 }
654
655 if (ivmode && cc->iv_gen_ops) {
656 if (ivopts)
657 *(ivopts - 1) = ':';
658 cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL);
659 if (!cc->iv_mode) {
72d94861 660 ti->error = "Error kmallocing iv_mode string";
1da177e4
LT		 661 goto bad5;
662 }
663 strcpy(cc->iv_mode, ivmode);
664 } else
665 cc->iv_mode = NULL;
666
667 ti->private = cc;
668 return 0;
669
670bad5:
671 mempool_destroy(cc->page_pool);
672bad4:
673 mempool_destroy(cc->io_pool);
674bad3:
675 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
676 cc->iv_gen_ops->dtr(cc);
677bad2:
678 crypto_free_tfm(tfm);
679bad1:
9d3520a3
SR		 680 /* Must zero key material before freeing */
681 memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
1da177e4
LT		 682 kfree(cc);
683 return -EINVAL;
684}
685
686static void crypt_dtr(struct dm_target *ti)
687{
688 struct crypt_config *cc = (struct crypt_config *) ti->private;
689
690 mempool_destroy(cc->page_pool);
691 mempool_destroy(cc->io_pool);
692
990a8baf 693 kfree(cc->iv_mode);
1da177e4
LT		 694 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
695 cc->iv_gen_ops->dtr(cc);
696 crypto_free_tfm(cc->tfm);
697 dm_put_device(ti, cc->dev);
9d3520a3
SR		 698
699 /* Must zero key material before freeing */
700 memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
1da177e4
LT		 701 kfree(cc);
702}
703
704static int crypt_endio(struct bio *bio, unsigned int done, int error)
705{
706 struct crypt_io *io = (struct crypt_io *) bio->bi_private;
707 struct crypt_config *cc = (struct crypt_config *) io->target->private;
708
709 if (bio_data_dir(bio) == WRITE) {
710 /*
711 * free the processed pages, even if
712 * it's only a partially completed write
713 */
714 crypt_free_buffer_pages(cc, bio, done);
715 }
716
717 if (bio->bi_size)
718 return 1;
719
720 bio_put(bio);
721
722 /*
723 * successful reads are decrypted by the worker thread
724 */
725 if ((bio_data_dir(bio) == READ)
726 && bio_flagged(bio, BIO_UPTODATE)) {
727 kcryptd_queue_io(io);
728 return 0;
729 }
730
731 dec_pending(io, error);
732 return error;
733}
734
735static inline struct bio *
736crypt_clone(struct crypt_config *cc, struct crypt_io *io, struct bio *bio,
737 sector_t sector, unsigned int *bvec_idx,
738 struct convert_context *ctx)
739{
740 struct bio *clone;
741
742 if (bio_data_dir(bio) == WRITE) {
743 clone = crypt_alloc_buffer(cc, bio->bi_size,
744 io->first_clone, bvec_idx);
745 if (clone) {
746 ctx->bio_out = clone;
747 if (crypt_convert(cc, ctx) < 0) {
748 crypt_free_buffer_pages(cc, clone,
749 clone->bi_size);
750 bio_put(clone);
751 return NULL;
752 }
753 }
754 } else {
755 /*
756 * The block layer might modify the bvec array, so always
757 * copy the required bvecs because we need the original
758 * one in order to decrypt the whole bio data *afterwards*.
759 */
760 clone = bio_alloc(GFP_NOIO, bio_segments(bio));
761 if (clone) {
762 clone->bi_idx = 0;
763 clone->bi_vcnt = bio_segments(bio);
764 clone->bi_size = bio->bi_size;
765 memcpy(clone->bi_io_vec, bio_iovec(bio),
766 sizeof(struct bio_vec) * clone->bi_vcnt);
767 }
768 }
769
770 if (!clone)
771 return NULL;
772
773 clone->bi_private = io;
774 clone->bi_end_io = crypt_endio;
775 clone->bi_bdev = cc->dev->bdev;
776 clone->bi_sector = cc->start + sector;
777 clone->bi_rw = bio->bi_rw;
778
779 return clone;
780}
781
782static int crypt_map(struct dm_target *ti, struct bio *bio,
783 union map_info *map_context)
784{
785 struct crypt_config *cc = (struct crypt_config *) ti->private;
786 struct crypt_io *io = mempool_alloc(cc->io_pool, GFP_NOIO);
787 struct convert_context ctx;
788 struct bio *clone;
789 unsigned int remaining = bio->bi_size;
790 sector_t sector = bio->bi_sector - ti->begin;
791 unsigned int bvec_idx = 0;
792
793 io->target = ti;
794 io->bio = bio;
795 io->first_clone = NULL;
796 io->error = 0;
797 atomic_set(&io->pending, 1); /* hold a reference */
798
799 if (bio_data_dir(bio) == WRITE)
800 crypt_convert_init(cc, &ctx, NULL, bio, sector, 1);
801
802 /*
803 * The allocated buffers can be smaller than the whole bio,
804 * so repeat the whole process until all the data can be handled.
805 */
806 while (remaining) {
807 clone = crypt_clone(cc, io, bio, sector, &bvec_idx, &ctx);
808 if (!clone)
809 goto cleanup;
810
811 if (!io->first_clone) {
812 /*
813 * hold a reference to the first clone, because it
814 * holds the bio_vec array and that can't be freed
815 * before all other clones are released
816 */
817 bio_get(clone);
818 io->first_clone = clone;
819 }
820 atomic_inc(&io->pending);
821
822 remaining -= clone->bi_size;
823 sector += bio_sectors(clone);
824
825 generic_make_request(clone);
826
827 /* out of memory -> run queues */
828 if (remaining)
829 blk_congestion_wait(bio_data_dir(clone), HZ/100);
830 }
831
832 /* drop reference, clones could have returned before we reach this */
833 dec_pending(io, 0);
834 return 0;
835
836cleanup:
837 if (io->first_clone) {
838 dec_pending(io, -ENOMEM);
839 return 0;
840 }
841
842 /* if no bio has been dispatched yet, we can directly return the error */
843 mempool_free(io, cc->io_pool);
844 return -ENOMEM;
845}
846
847static int crypt_status(struct dm_target *ti, status_type_t type,
848 char *result, unsigned int maxlen)
849{
850 struct crypt_config *cc = (struct crypt_config *) ti->private;
851 const char *cipher;
852 const char *chainmode = NULL;
853 unsigned int sz = 0;
854
855 switch (type) {
856 case STATUSTYPE_INFO:
857 result[0] = '\0';
858 break;
859
860 case STATUSTYPE_TABLE:
861 cipher = crypto_tfm_alg_name(cc->tfm);
862
863 switch(cc->tfm->crt_cipher.cit_mode) {
864 case CRYPTO_TFM_MODE_CBC:
865 chainmode = "cbc";
866 break;
867 case CRYPTO_TFM_MODE_ECB:
868 chainmode = "ecb";
869 break;
870 default:
871 BUG();
872 }
873
874 if (cc->iv_mode)
875 DMEMIT("%s-%s-%s ", cipher, chainmode, cc->iv_mode);
876 else
877 DMEMIT("%s-%s ", cipher, chainmode);
878
879 if (cc->key_size > 0) {
880 if ((maxlen - sz) < ((cc->key_size << 1) + 1))
881 return -ENOMEM;
882
883 crypt_encode_key(result + sz, cc->key, cc->key_size);
884 sz += cc->key_size << 1;
885 } else {
886 if (sz >= maxlen)
887 return -ENOMEM;
888 result[sz++] = '-';
889 }
890
4ee218cd
AM		 891 DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
892 cc->dev->name, (unsigned long long)cc->start);
1da177e4
LT		 893 break;
894 }
895 return 0;
896}
897
898static struct target_type crypt_target = {
899 .name = "crypt",
900 .version= {1, 1, 0},
901 .module = THIS_MODULE,
902 .ctr = crypt_ctr,
903 .dtr = crypt_dtr,
904 .map = crypt_map,
905 .status = crypt_status,
906};
907
908static int __init dm_crypt_init(void)
909{
910 int r;
911
912 _crypt_io_pool = kmem_cache_create("dm-crypt_io",
913 sizeof(struct crypt_io),
914 0, 0, NULL, NULL);
915 if (!_crypt_io_pool)
916 return -ENOMEM;
917
918 _kcryptd_workqueue = create_workqueue("kcryptd");
919 if (!_kcryptd_workqueue) {
920 r = -ENOMEM;
72d94861 921 DMERR("couldn't create kcryptd");
1da177e4
LT		 922 goto bad1;
923 }
924
925 r = dm_register_target(&crypt_target);
926 if (r < 0) {
72d94861 927 DMERR("register failed %d", r);
1da177e4
LT		 928 goto bad2;
929 }
930
931 return 0;
932
933bad2:
934 destroy_workqueue(_kcryptd_workqueue);
935bad1:
936 kmem_cache_destroy(_crypt_io_pool);
937 return r;
938}
939
940static void __exit dm_crypt_exit(void)
941{
942 int r = dm_unregister_target(&crypt_target);
943
944 if (r < 0)
72d94861 945 DMERR("unregister failed %d", r);
1da177e4
LT		 946
947 destroy_workqueue(_kcryptd_workqueue);
948 kmem_cache_destroy(_crypt_io_pool);
949}
950
951module_init(dm_crypt_init);
952module_exit(dm_crypt_exit);
953
954MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
955MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
956MODULE_LICENSE("GPL");
kernel source for telekom puls (alcatel/mediatek)