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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/md/dm-crypt.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'drivers/md/dm-crypt.c')
-rw-r--r--drivers/md/dm-crypt.c977
1 files changed, 977 insertions, 0 deletions
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
new file mode 100644
index 000000000000..77619a56e2bf
--- /dev/null
+++ b/drivers/md/dm-crypt.c
@@ -0,0 +1,977 @@
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>
18#include <asm/scatterlist.h>
19#include <asm/page.h>
20
21#include "dm.h"
22
23#define PFX "crypt: "
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
96/*
97 * Mempool alloc and free functions for the page
98 */
99static void *mempool_alloc_page(unsigned int __nocast gfp_mask, void *data)
100{
101 return alloc_page(gfp_mask);
102}
103
104static void mempool_free_page(void *page, void *data)
105{
106 __free_page(page);
107}
108
109
110/*
111 * Different IV generation algorithms:
112 *
113 * plain: the initial vector is the 32-bit low-endian version of the sector
114 * number, padded with zeros if neccessary.
115 *
116 * ess_iv: "encrypted sector|salt initial vector", the sector number is
117 * encrypted with the bulk cipher using a salt as key. The salt
118 * should be derived from the bulk cipher's key via hashing.
119 *
120 * plumb: unimplemented, see:
121 * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
122 */
123
124static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
125{
126 memset(iv, 0, cc->iv_size);
127 *(u32 *)iv = cpu_to_le32(sector & 0xffffffff);
128
129 return 0;
130}
131
132static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
133 const char *opts)
134{
135 struct crypto_tfm *essiv_tfm;
136 struct crypto_tfm *hash_tfm;
137 struct scatterlist sg;
138 unsigned int saltsize;
139 u8 *salt;
140
141 if (opts == NULL) {
142 ti->error = PFX "Digest algorithm missing for ESSIV mode";
143 return -EINVAL;
144 }
145
146 /* Hash the cipher key with the given hash algorithm */
147 hash_tfm = crypto_alloc_tfm(opts, 0);
148 if (hash_tfm == NULL) {
149 ti->error = PFX "Error initializing ESSIV hash";
150 return -EINVAL;
151 }
152
153 if (crypto_tfm_alg_type(hash_tfm) != CRYPTO_ALG_TYPE_DIGEST) {
154 ti->error = PFX "Expected digest algorithm for ESSIV hash";
155 crypto_free_tfm(hash_tfm);
156 return -EINVAL;
157 }
158
159 saltsize = crypto_tfm_alg_digestsize(hash_tfm);
160 salt = kmalloc(saltsize, GFP_KERNEL);
161 if (salt == NULL) {
162 ti->error = PFX "Error kmallocing salt storage in ESSIV";
163 crypto_free_tfm(hash_tfm);
164 return -ENOMEM;
165 }
166
167 sg.page = virt_to_page(cc->key);
168 sg.offset = offset_in_page(cc->key);
169 sg.length = cc->key_size;
170 crypto_digest_digest(hash_tfm, &sg, 1, salt);
171 crypto_free_tfm(hash_tfm);
172
173 /* Setup the essiv_tfm with the given salt */
174 essiv_tfm = crypto_alloc_tfm(crypto_tfm_alg_name(cc->tfm),
175 CRYPTO_TFM_MODE_ECB);
176 if (essiv_tfm == NULL) {
177 ti->error = PFX "Error allocating crypto tfm for ESSIV";
178 kfree(salt);
179 return -EINVAL;
180 }
181 if (crypto_tfm_alg_blocksize(essiv_tfm)
182 != crypto_tfm_alg_ivsize(cc->tfm)) {
183 ti->error = PFX "Block size of ESSIV cipher does "
184 "not match IV size of block cipher";
185 crypto_free_tfm(essiv_tfm);
186 kfree(salt);
187 return -EINVAL;
188 }
189 if (crypto_cipher_setkey(essiv_tfm, salt, saltsize) < 0) {
190 ti->error = PFX "Failed to set key for ESSIV cipher";
191 crypto_free_tfm(essiv_tfm);
192 kfree(salt);
193 return -EINVAL;
194 }
195 kfree(salt);
196
197 cc->iv_gen_private = (void *)essiv_tfm;
198 return 0;
199}
200
201static void crypt_iv_essiv_dtr(struct crypt_config *cc)
202{
203 crypto_free_tfm((struct crypto_tfm *)cc->iv_gen_private);
204 cc->iv_gen_private = NULL;
205}
206
207static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
208{
209 struct scatterlist sg = { NULL, };
210
211 memset(iv, 0, cc->iv_size);
212 *(u64 *)iv = cpu_to_le64(sector);
213
214 sg.page = virt_to_page(iv);
215 sg.offset = offset_in_page(iv);
216 sg.length = cc->iv_size;
217 crypto_cipher_encrypt((struct crypto_tfm *)cc->iv_gen_private,
218 &sg, &sg, cc->iv_size);
219
220 return 0;
221}
222
223static struct crypt_iv_operations crypt_iv_plain_ops = {
224 .generator = crypt_iv_plain_gen
225};
226
227static struct crypt_iv_operations crypt_iv_essiv_ops = {
228 .ctr = crypt_iv_essiv_ctr,
229 .dtr = crypt_iv_essiv_dtr,
230 .generator = crypt_iv_essiv_gen
231};
232
233
234static inline int
235crypt_convert_scatterlist(struct crypt_config *cc, struct scatterlist *out,
236 struct scatterlist *in, unsigned int length,
237 int write, sector_t sector)
238{
239 u8 iv[cc->iv_size];
240 int r;
241
242 if (cc->iv_gen_ops) {
243 r = cc->iv_gen_ops->generator(cc, iv, sector);
244 if (r < 0)
245 return r;
246
247 if (write)
248 r = crypto_cipher_encrypt_iv(cc->tfm, out, in, length, iv);
249 else
250 r = crypto_cipher_decrypt_iv(cc->tfm, out, in, length, iv);
251 } else {
252 if (write)
253 r = crypto_cipher_encrypt(cc->tfm, out, in, length);
254 else
255 r = crypto_cipher_decrypt(cc->tfm, out, in, length);
256 }
257
258 return r;
259}
260
261static void
262crypt_convert_init(struct crypt_config *cc, struct convert_context *ctx,
263 struct bio *bio_out, struct bio *bio_in,
264 sector_t sector, int write)
265{
266 ctx->bio_in = bio_in;
267 ctx->bio_out = bio_out;
268 ctx->offset_in = 0;
269 ctx->offset_out = 0;
270 ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
271 ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
272 ctx->sector = sector + cc->iv_offset;
273 ctx->write = write;
274}
275
276/*
277 * Encrypt / decrypt data from one bio to another one (can be the same one)
278 */
279static int crypt_convert(struct crypt_config *cc,
280 struct convert_context *ctx)
281{
282 int r = 0;
283
284 while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
285 ctx->idx_out < ctx->bio_out->bi_vcnt) {
286 struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
287 struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
288 struct scatterlist sg_in = {
289 .page = bv_in->bv_page,
290 .offset = bv_in->bv_offset + ctx->offset_in,
291 .length = 1 << SECTOR_SHIFT
292 };
293 struct scatterlist sg_out = {
294 .page = bv_out->bv_page,
295 .offset = bv_out->bv_offset + ctx->offset_out,
296 .length = 1 << SECTOR_SHIFT
297 };
298
299 ctx->offset_in += sg_in.length;
300 if (ctx->offset_in >= bv_in->bv_len) {
301 ctx->offset_in = 0;
302 ctx->idx_in++;
303 }
304
305 ctx->offset_out += sg_out.length;
306 if (ctx->offset_out >= bv_out->bv_len) {
307 ctx->offset_out = 0;
308 ctx->idx_out++;
309 }
310
311 r = crypt_convert_scatterlist(cc, &sg_out, &sg_in, sg_in.length,
312 ctx->write, ctx->sector);
313 if (r < 0)
314 break;
315
316 ctx->sector++;
317 }
318
319 return r;
320}
321
322/*
323 * Generate a new unfragmented bio with the given size
324 * This should never violate the device limitations
325 * May return a smaller bio when running out of pages
326 */
327static struct bio *
328crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
329 struct bio *base_bio, unsigned int *bio_vec_idx)
330{
331 struct bio *bio;
332 unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
333 int gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
334 unsigned long flags = current->flags;
335 unsigned int i;
336
337 /*
338 * Tell VM to act less aggressively and fail earlier.
339 * This is not necessary but increases throughput.
340 * FIXME: Is this really intelligent?
341 */
342 current->flags &= ~PF_MEMALLOC;
343
344 if (base_bio)
345 bio = bio_clone(base_bio, GFP_NOIO);
346 else
347 bio = bio_alloc(GFP_NOIO, nr_iovecs);
348 if (!bio) {
349 if (flags & PF_MEMALLOC)
350 current->flags |= PF_MEMALLOC;
351 return NULL;
352 }
353
354 /* if the last bio was not complete, continue where that one ended */
355 bio->bi_idx = *bio_vec_idx;
356 bio->bi_vcnt = *bio_vec_idx;
357 bio->bi_size = 0;
358 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
359
360 /* bio->bi_idx pages have already been allocated */
361 size -= bio->bi_idx * PAGE_SIZE;
362
363 for(i = bio->bi_idx; i < nr_iovecs; i++) {
364 struct bio_vec *bv = bio_iovec_idx(bio, i);
365
366 bv->bv_page = mempool_alloc(cc->page_pool, gfp_mask);
367 if (!bv->bv_page)
368 break;
369
370 /*
371 * if additional pages cannot be allocated without waiting,
372 * return a partially allocated bio, the caller will then try
373 * to allocate additional bios while submitting this partial bio
374 */
375 if ((i - bio->bi_idx) == (MIN_BIO_PAGES - 1))
376 gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
377
378 bv->bv_offset = 0;
379 if (size > PAGE_SIZE)
380 bv->bv_len = PAGE_SIZE;
381 else
382 bv->bv_len = size;
383
384 bio->bi_size += bv->bv_len;
385 bio->bi_vcnt++;
386 size -= bv->bv_len;
387 }
388
389 if (flags & PF_MEMALLOC)
390 current->flags |= PF_MEMALLOC;
391
392 if (!bio->bi_size) {
393 bio_put(bio);
394 return NULL;
395 }
396
397 /*
398 * Remember the last bio_vec allocated to be able
399 * to correctly continue after the splitting.
400 */
401 *bio_vec_idx = bio->bi_vcnt;
402
403 return bio;
404}
405
406static void crypt_free_buffer_pages(struct crypt_config *cc,
407 struct bio *bio, unsigned int bytes)
408{
409 unsigned int i, start, end;
410 struct bio_vec *bv;
411
412 /*
413 * This is ugly, but Jens Axboe thinks that using bi_idx in the
414 * endio function is too dangerous at the moment, so I calculate the
415 * correct position using bi_vcnt and bi_size.
416 * The bv_offset and bv_len fields might already be modified but we
417 * know that we always allocated whole pages.
418 * A fix to the bi_idx issue in the kernel is in the works, so
419 * we will hopefully be able to revert to the cleaner solution soon.
420 */
421 i = bio->bi_vcnt - 1;
422 bv = bio_iovec_idx(bio, i);
423 end = (i << PAGE_SHIFT) + (bv->bv_offset + bv->bv_len) - bio->bi_size;
424 start = end - bytes;
425
426 start >>= PAGE_SHIFT;
427 if (!bio->bi_size)
428 end = bio->bi_vcnt;
429 else
430 end >>= PAGE_SHIFT;
431
432 for(i = start; i < end; i++) {
433 bv = bio_iovec_idx(bio, i);
434 BUG_ON(!bv->bv_page);
435 mempool_free(bv->bv_page, cc->page_pool);
436 bv->bv_page = NULL;
437 }
438}
439
440/*
441 * One of the bios was finished. Check for completion of
442 * the whole request and correctly clean up the buffer.
443 */
444static void dec_pending(struct crypt_io *io, int error)
445{
446 struct crypt_config *cc = (struct crypt_config *) io->target->private;
447
448 if (error < 0)
449 io->error = error;
450
451 if (!atomic_dec_and_test(&io->pending))
452 return;
453
454 if (io->first_clone)
455 bio_put(io->first_clone);
456
457 bio_endio(io->bio, io->bio->bi_size, io->error);
458
459 mempool_free(io, cc->io_pool);
460}
461
462/*
463 * kcryptd:
464 *
465 * Needed because it would be very unwise to do decryption in an
466 * interrupt context, so bios returning from read requests get
467 * queued here.
468 */
469static struct workqueue_struct *_kcryptd_workqueue;
470
471static void kcryptd_do_work(void *data)
472{
473 struct crypt_io *io = (struct crypt_io *) data;
474 struct crypt_config *cc = (struct crypt_config *) io->target->private;
475 struct convert_context ctx;
476 int r;
477
478 crypt_convert_init(cc, &ctx, io->bio, io->bio,
479 io->bio->bi_sector - io->target->begin, 0);
480 r = crypt_convert(cc, &ctx);
481
482 dec_pending(io, r);
483}
484
485static void kcryptd_queue_io(struct crypt_io *io)
486{
487 INIT_WORK(&io->work, kcryptd_do_work, io);
488 queue_work(_kcryptd_workqueue, &io->work);
489}
490
491/*
492 * Decode key from its hex representation
493 */
494static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
495{
496 char buffer[3];
497 char *endp;
498 unsigned int i;
499
500 buffer[2] = '\0';
501
502 for(i = 0; i < size; i++) {
503 buffer[0] = *hex++;
504 buffer[1] = *hex++;
505
506 key[i] = (u8)simple_strtoul(buffer, &endp, 16);
507
508 if (endp != &buffer[2])
509 return -EINVAL;
510 }
511
512 if (*hex != '\0')
513 return -EINVAL;
514
515 return 0;
516}
517
518/*
519 * Encode key into its hex representation
520 */
521static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
522{
523 unsigned int i;
524
525 for(i = 0; i < size; i++) {
526 sprintf(hex, "%02x", *key);
527 hex += 2;
528 key++;
529 }
530}
531
532/*
533 * Construct an encryption mapping:
534 * <cipher> <key> <iv_offset> <dev_path> <start>
535 */
536static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
537{
538 struct crypt_config *cc;
539 struct crypto_tfm *tfm;
540 char *tmp;
541 char *cipher;
542 char *chainmode;
543 char *ivmode;
544 char *ivopts;
545 unsigned int crypto_flags;
546 unsigned int key_size;
547
548 if (argc != 5) {
549 ti->error = PFX "Not enough arguments";
550 return -EINVAL;
551 }
552
553 tmp = argv[0];
554 cipher = strsep(&tmp, "-");
555 chainmode = strsep(&tmp, "-");
556 ivopts = strsep(&tmp, "-");
557 ivmode = strsep(&ivopts, ":");
558
559 if (tmp)
560 DMWARN(PFX "Unexpected additional cipher options");
561
562 key_size = strlen(argv[1]) >> 1;
563
564 cc = kmalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
565 if (cc == NULL) {
566 ti->error =
567 PFX "Cannot allocate transparent encryption context";
568 return -ENOMEM;
569 }
570
571 cc->key_size = key_size;
572 if ((!key_size && strcmp(argv[1], "-") != 0) ||
573 (key_size && crypt_decode_key(cc->key, argv[1], key_size) < 0)) {
574 ti->error = PFX "Error decoding key";
575 goto bad1;
576 }
577
578 /* Compatiblity mode for old dm-crypt cipher strings */
579 if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
580 chainmode = "cbc";
581 ivmode = "plain";
582 }
583
584 /* Choose crypto_flags according to chainmode */
585 if (strcmp(chainmode, "cbc") == 0)
586 crypto_flags = CRYPTO_TFM_MODE_CBC;
587 else if (strcmp(chainmode, "ecb") == 0)
588 crypto_flags = CRYPTO_TFM_MODE_ECB;
589 else {
590 ti->error = PFX "Unknown chaining mode";
591 goto bad1;
592 }
593
594 if (crypto_flags != CRYPTO_TFM_MODE_ECB && !ivmode) {
595 ti->error = PFX "This chaining mode requires an IV mechanism";
596 goto bad1;
597 }
598
599 tfm = crypto_alloc_tfm(cipher, crypto_flags);
600 if (!tfm) {
601 ti->error = PFX "Error allocating crypto tfm";
602 goto bad1;
603 }
604 if (crypto_tfm_alg_type(tfm) != CRYPTO_ALG_TYPE_CIPHER) {
605 ti->error = PFX "Expected cipher algorithm";
606 goto bad2;
607 }
608
609 cc->tfm = tfm;
610
611 /*
612 * Choose ivmode. Valid modes: "plain", "essiv:<esshash>".
613 * See comments at iv code
614 */
615
616 if (ivmode == NULL)
617 cc->iv_gen_ops = NULL;
618 else if (strcmp(ivmode, "plain") == 0)
619 cc->iv_gen_ops = &crypt_iv_plain_ops;
620 else if (strcmp(ivmode, "essiv") == 0)
621 cc->iv_gen_ops = &crypt_iv_essiv_ops;
622 else {
623 ti->error = PFX "Invalid IV mode";
624 goto bad2;
625 }
626
627 if (cc->iv_gen_ops && cc->iv_gen_ops->ctr &&
628 cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
629 goto bad2;
630
631 if (tfm->crt_cipher.cit_decrypt_iv && tfm->crt_cipher.cit_encrypt_iv)
632 /* at least a 64 bit sector number should fit in our buffer */
633 cc->iv_size = max(crypto_tfm_alg_ivsize(tfm),
634 (unsigned int)(sizeof(u64) / sizeof(u8)));
635 else {
636 cc->iv_size = 0;
637 if (cc->iv_gen_ops) {
638 DMWARN(PFX "Selected cipher does not support IVs");
639 if (cc->iv_gen_ops->dtr)
640 cc->iv_gen_ops->dtr(cc);
641 cc->iv_gen_ops = NULL;
642 }
643 }
644
645 cc->io_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
646 mempool_free_slab, _crypt_io_pool);
647 if (!cc->io_pool) {
648 ti->error = PFX "Cannot allocate crypt io mempool";
649 goto bad3;
650 }
651
652 cc->page_pool = mempool_create(MIN_POOL_PAGES, mempool_alloc_page,
653 mempool_free_page, NULL);
654 if (!cc->page_pool) {
655 ti->error = PFX "Cannot allocate page mempool";
656 goto bad4;
657 }
658
659 if (tfm->crt_cipher.cit_setkey(tfm, cc->key, key_size) < 0) {
660 ti->error = PFX "Error setting key";
661 goto bad5;
662 }
663
664 if (sscanf(argv[2], SECTOR_FORMAT, &cc->iv_offset) != 1) {
665 ti->error = PFX "Invalid iv_offset sector";
666 goto bad5;
667 }
668
669 if (sscanf(argv[4], SECTOR_FORMAT, &cc->start) != 1) {
670 ti->error = PFX "Invalid device sector";
671 goto bad5;
672 }
673
674 if (dm_get_device(ti, argv[3], cc->start, ti->len,
675 dm_table_get_mode(ti->table), &cc->dev)) {
676 ti->error = PFX "Device lookup failed";
677 goto bad5;
678 }
679
680 if (ivmode && cc->iv_gen_ops) {
681 if (ivopts)
682 *(ivopts - 1) = ':';
683 cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL);
684 if (!cc->iv_mode) {
685 ti->error = PFX "Error kmallocing iv_mode string";
686 goto bad5;
687 }
688 strcpy(cc->iv_mode, ivmode);
689 } else
690 cc->iv_mode = NULL;
691
692 ti->private = cc;
693 return 0;
694
695bad5:
696 mempool_destroy(cc->page_pool);
697bad4:
698 mempool_destroy(cc->io_pool);
699bad3:
700 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
701 cc->iv_gen_ops->dtr(cc);
702bad2:
703 crypto_free_tfm(tfm);
704bad1:
705 kfree(cc);
706 return -EINVAL;
707}
708
709static void crypt_dtr(struct dm_target *ti)
710{
711 struct crypt_config *cc = (struct crypt_config *) ti->private;
712
713 mempool_destroy(cc->page_pool);
714 mempool_destroy(cc->io_pool);
715
716 if (cc->iv_mode)
717 kfree(cc->iv_mode);
718 if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
719 cc->iv_gen_ops->dtr(cc);
720 crypto_free_tfm(cc->tfm);
721 dm_put_device(ti, cc->dev);
722 kfree(cc);
723}
724
725static int crypt_endio(struct bio *bio, unsigned int done, int error)
726{
727 struct crypt_io *io = (struct crypt_io *) bio->bi_private;
728 struct crypt_config *cc = (struct crypt_config *) io->target->private;
729
730 if (bio_data_dir(bio) == WRITE) {
731 /*
732 * free the processed pages, even if
733 * it's only a partially completed write
734 */
735 crypt_free_buffer_pages(cc, bio, done);
736 }
737
738 if (bio->bi_size)
739 return 1;
740
741 bio_put(bio);
742
743 /*
744 * successful reads are decrypted by the worker thread
745 */
746 if ((bio_data_dir(bio) == READ)
747 && bio_flagged(bio, BIO_UPTODATE)) {
748 kcryptd_queue_io(io);
749 return 0;
750 }
751
752 dec_pending(io, error);
753 return error;
754}
755
756static inline struct bio *
757crypt_clone(struct crypt_config *cc, struct crypt_io *io, struct bio *bio,
758 sector_t sector, unsigned int *bvec_idx,
759 struct convert_context *ctx)
760{
761 struct bio *clone;
762
763 if (bio_data_dir(bio) == WRITE) {
764 clone = crypt_alloc_buffer(cc, bio->bi_size,
765 io->first_clone, bvec_idx);
766 if (clone) {
767 ctx->bio_out = clone;
768 if (crypt_convert(cc, ctx) < 0) {
769 crypt_free_buffer_pages(cc, clone,
770 clone->bi_size);
771 bio_put(clone);
772 return NULL;
773 }
774 }
775 } else {
776 /*
777 * The block layer might modify the bvec array, so always
778 * copy the required bvecs because we need the original
779 * one in order to decrypt the whole bio data *afterwards*.
780 */
781 clone = bio_alloc(GFP_NOIO, bio_segments(bio));
782 if (clone) {
783 clone->bi_idx = 0;
784 clone->bi_vcnt = bio_segments(bio);
785 clone->bi_size = bio->bi_size;
786 memcpy(clone->bi_io_vec, bio_iovec(bio),
787 sizeof(struct bio_vec) * clone->bi_vcnt);
788 }
789 }
790
791 if (!clone)
792 return NULL;
793
794 clone->bi_private = io;
795 clone->bi_end_io = crypt_endio;
796 clone->bi_bdev = cc->dev->bdev;
797 clone->bi_sector = cc->start + sector;
798 clone->bi_rw = bio->bi_rw;
799
800 return clone;
801}
802
803static int crypt_map(struct dm_target *ti, struct bio *bio,
804 union map_info *map_context)
805{
806 struct crypt_config *cc = (struct crypt_config *) ti->private;
807 struct crypt_io *io = mempool_alloc(cc->io_pool, GFP_NOIO);
808 struct convert_context ctx;
809 struct bio *clone;
810 unsigned int remaining = bio->bi_size;
811 sector_t sector = bio->bi_sector - ti->begin;
812 unsigned int bvec_idx = 0;
813
814 io->target = ti;
815 io->bio = bio;
816 io->first_clone = NULL;
817 io->error = 0;
818 atomic_set(&io->pending, 1); /* hold a reference */
819
820 if (bio_data_dir(bio) == WRITE)
821 crypt_convert_init(cc, &ctx, NULL, bio, sector, 1);
822
823 /*
824 * The allocated buffers can be smaller than the whole bio,
825 * so repeat the whole process until all the data can be handled.
826 */
827 while (remaining) {
828 clone = crypt_clone(cc, io, bio, sector, &bvec_idx, &ctx);
829 if (!clone)
830 goto cleanup;
831
832 if (!io->first_clone) {
833 /*
834 * hold a reference to the first clone, because it
835 * holds the bio_vec array and that can't be freed
836 * before all other clones are released
837 */
838 bio_get(clone);
839 io->first_clone = clone;
840 }
841 atomic_inc(&io->pending);
842
843 remaining -= clone->bi_size;
844 sector += bio_sectors(clone);
845
846 generic_make_request(clone);
847
848 /* out of memory -> run queues */
849 if (remaining)
850 blk_congestion_wait(bio_data_dir(clone), HZ/100);
851 }
852
853 /* drop reference, clones could have returned before we reach this */
854 dec_pending(io, 0);
855 return 0;
856
857cleanup:
858 if (io->first_clone) {
859 dec_pending(io, -ENOMEM);
860 return 0;
861 }
862
863 /* if no bio has been dispatched yet, we can directly return the error */
864 mempool_free(io, cc->io_pool);
865 return -ENOMEM;
866}
867
868static int crypt_status(struct dm_target *ti, status_type_t type,
869 char *result, unsigned int maxlen)
870{
871 struct crypt_config *cc = (struct crypt_config *) ti->private;
872 const char *cipher;
873 const char *chainmode = NULL;
874 unsigned int sz = 0;
875
876 switch (type) {
877 case STATUSTYPE_INFO:
878 result[0] = '\0';
879 break;
880
881 case STATUSTYPE_TABLE:
882 cipher = crypto_tfm_alg_name(cc->tfm);
883
884 switch(cc->tfm->crt_cipher.cit_mode) {
885 case CRYPTO_TFM_MODE_CBC:
886 chainmode = "cbc";
887 break;
888 case CRYPTO_TFM_MODE_ECB:
889 chainmode = "ecb";
890 break;
891 default:
892 BUG();
893 }
894
895 if (cc->iv_mode)
896 DMEMIT("%s-%s-%s ", cipher, chainmode, cc->iv_mode);
897 else
898 DMEMIT("%s-%s ", cipher, chainmode);
899
900 if (cc->key_size > 0) {
901 if ((maxlen - sz) < ((cc->key_size << 1) + 1))
902 return -ENOMEM;
903
904 crypt_encode_key(result + sz, cc->key, cc->key_size);
905 sz += cc->key_size << 1;
906 } else {
907 if (sz >= maxlen)
908 return -ENOMEM;
909 result[sz++] = '-';
910 }
911
912 DMEMIT(" " SECTOR_FORMAT " %s " SECTOR_FORMAT,
913 cc->iv_offset, cc->dev->name, cc->start);
914 break;
915 }
916 return 0;
917}
918
919static struct target_type crypt_target = {
920 .name = "crypt",
921 .version= {1, 1, 0},
922 .module = THIS_MODULE,
923 .ctr = crypt_ctr,
924 .dtr = crypt_dtr,
925 .map = crypt_map,
926 .status = crypt_status,
927};
928
929static int __init dm_crypt_init(void)
930{
931 int r;
932
933 _crypt_io_pool = kmem_cache_create("dm-crypt_io",
934 sizeof(struct crypt_io),
935 0, 0, NULL, NULL);
936 if (!_crypt_io_pool)
937 return -ENOMEM;
938
939 _kcryptd_workqueue = create_workqueue("kcryptd");
940 if (!_kcryptd_workqueue) {
941 r = -ENOMEM;
942 DMERR(PFX "couldn't create kcryptd");
943 goto bad1;
944 }
945
946 r = dm_register_target(&crypt_target);
947 if (r < 0) {
948 DMERR(PFX "register failed %d", r);
949 goto bad2;
950 }
951
952 return 0;
953
954bad2:
955 destroy_workqueue(_kcryptd_workqueue);
956bad1:
957 kmem_cache_destroy(_crypt_io_pool);
958 return r;
959}
960
961static void __exit dm_crypt_exit(void)
962{
963 int r = dm_unregister_target(&crypt_target);
964
965 if (r < 0)
966 DMERR(PFX "unregister failed %d", r);
967
968 destroy_workqueue(_kcryptd_workqueue);
969 kmem_cache_destroy(_crypt_io_pool);
970}
971
972module_init(dm_crypt_init);
973module_exit(dm_crypt_exit);
974
975MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
976MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
977MODULE_LICENSE("GPL");