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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2003 Christophe Saout <christophe@saout.de> | |
3 | * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org> | |
e48d4bbf | 4 | * Copyright (C) 2006 Red Hat, Inc. All rights reserved. |
1da177e4 LT |
5 | * |
6 | * This file is released under the GPL. | |
7 | */ | |
8 | ||
d1806f6a | 9 | #include <linux/err.h> |
1da177e4 LT |
10 | #include <linux/module.h> |
11 | #include <linux/init.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/bio.h> | |
14 | #include <linux/blkdev.h> | |
15 | #include <linux/mempool.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/crypto.h> | |
18 | #include <linux/workqueue.h> | |
19 | #include <asm/atomic.h> | |
378f058c | 20 | #include <linux/scatterlist.h> |
1da177e4 LT |
21 | #include <asm/page.h> |
22 | ||
23 | #include "dm.h" | |
24 | ||
72d94861 | 25 | #define DM_MSG_PREFIX "crypt" |
e48d4bbf | 26 | #define MESG_STR(x) x, sizeof(x) |
1da177e4 LT |
27 | |
28 | /* | |
29 | * per bio private data | |
30 | */ | |
31 | struct crypt_io { | |
32 | struct dm_target *target; | |
33 | struct bio *bio; | |
34 | struct bio *first_clone; | |
35 | struct work_struct work; | |
36 | atomic_t pending; | |
37 | int error; | |
38 | }; | |
39 | ||
40 | /* | |
41 | * context holding the current state of a multi-part conversion | |
42 | */ | |
43 | struct convert_context { | |
44 | struct bio *bio_in; | |
45 | struct bio *bio_out; | |
46 | unsigned int offset_in; | |
47 | unsigned int offset_out; | |
48 | unsigned int idx_in; | |
49 | unsigned int idx_out; | |
50 | sector_t sector; | |
51 | int write; | |
52 | }; | |
53 | ||
54 | struct crypt_config; | |
55 | ||
56 | struct crypt_iv_operations { | |
57 | int (*ctr)(struct crypt_config *cc, struct dm_target *ti, | |
58 | const char *opts); | |
59 | void (*dtr)(struct crypt_config *cc); | |
60 | const char *(*status)(struct crypt_config *cc); | |
61 | int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector); | |
62 | }; | |
63 | ||
64 | /* | |
65 | * Crypt: maps a linear range of a block device | |
66 | * and encrypts / decrypts at the same time. | |
67 | */ | |
e48d4bbf | 68 | enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID }; |
1da177e4 LT |
69 | struct crypt_config { |
70 | struct dm_dev *dev; | |
71 | sector_t start; | |
72 | ||
73 | /* | |
74 | * pool for per bio private data and | |
75 | * for encryption buffer pages | |
76 | */ | |
77 | mempool_t *io_pool; | |
78 | mempool_t *page_pool; | |
79 | ||
80 | /* | |
81 | * crypto related data | |
82 | */ | |
83 | struct crypt_iv_operations *iv_gen_ops; | |
84 | char *iv_mode; | |
d1806f6a | 85 | struct crypto_cipher *iv_gen_private; |
1da177e4 LT |
86 | sector_t iv_offset; |
87 | unsigned int iv_size; | |
88 | ||
d1806f6a HX |
89 | char cipher[CRYPTO_MAX_ALG_NAME]; |
90 | char chainmode[CRYPTO_MAX_ALG_NAME]; | |
91 | struct crypto_blkcipher *tfm; | |
e48d4bbf | 92 | unsigned long flags; |
1da177e4 LT |
93 | unsigned int key_size; |
94 | u8 key[0]; | |
95 | }; | |
96 | ||
97 | #define MIN_IOS 256 | |
98 | #define MIN_POOL_PAGES 32 | |
99 | #define MIN_BIO_PAGES 8 | |
100 | ||
101 | static kmem_cache_t *_crypt_io_pool; | |
102 | ||
1da177e4 LT |
103 | /* |
104 | * Different IV generation algorithms: | |
105 | * | |
3c164bd8 | 106 | * plain: the initial vector is the 32-bit little-endian version of the sector |
1da177e4 LT |
107 | * number, padded with zeros if neccessary. |
108 | * | |
3c164bd8 RS |
109 | * essiv: "encrypted sector|salt initial vector", the sector number is |
110 | * encrypted with the bulk cipher using a salt as key. The salt | |
111 | * should be derived from the bulk cipher's key via hashing. | |
1da177e4 LT |
112 | * |
113 | * plumb: unimplemented, see: | |
114 | * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454 | |
115 | */ | |
116 | ||
117 | static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector) | |
118 | { | |
119 | memset(iv, 0, cc->iv_size); | |
120 | *(u32 *)iv = cpu_to_le32(sector & 0xffffffff); | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
125 | static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, | |
126 | const char *opts) | |
127 | { | |
d1806f6a | 128 | struct crypto_cipher *essiv_tfm; |
35058687 HX |
129 | struct crypto_hash *hash_tfm; |
130 | struct hash_desc desc; | |
1da177e4 LT |
131 | struct scatterlist sg; |
132 | unsigned int saltsize; | |
133 | u8 *salt; | |
d1806f6a | 134 | int err; |
1da177e4 LT |
135 | |
136 | if (opts == NULL) { | |
72d94861 | 137 | ti->error = "Digest algorithm missing for ESSIV mode"; |
1da177e4 LT |
138 | return -EINVAL; |
139 | } | |
140 | ||
141 | /* Hash the cipher key with the given hash algorithm */ | |
35058687 HX |
142 | hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC); |
143 | if (IS_ERR(hash_tfm)) { | |
72d94861 | 144 | ti->error = "Error initializing ESSIV hash"; |
35058687 | 145 | return PTR_ERR(hash_tfm); |
1da177e4 LT |
146 | } |
147 | ||
35058687 | 148 | saltsize = crypto_hash_digestsize(hash_tfm); |
1da177e4 LT |
149 | salt = kmalloc(saltsize, GFP_KERNEL); |
150 | if (salt == NULL) { | |
72d94861 | 151 | ti->error = "Error kmallocing salt storage in ESSIV"; |
35058687 | 152 | crypto_free_hash(hash_tfm); |
1da177e4 LT |
153 | return -ENOMEM; |
154 | } | |
155 | ||
378f058c | 156 | sg_set_buf(&sg, cc->key, cc->key_size); |
35058687 HX |
157 | desc.tfm = hash_tfm; |
158 | desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; | |
159 | err = crypto_hash_digest(&desc, &sg, cc->key_size, salt); | |
160 | crypto_free_hash(hash_tfm); | |
161 | ||
162 | if (err) { | |
163 | ti->error = "Error calculating hash in ESSIV"; | |
164 | return err; | |
165 | } | |
1da177e4 LT |
166 | |
167 | /* Setup the essiv_tfm with the given salt */ | |
d1806f6a HX |
168 | essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC); |
169 | if (IS_ERR(essiv_tfm)) { | |
72d94861 | 170 | ti->error = "Error allocating crypto tfm for ESSIV"; |
1da177e4 | 171 | kfree(salt); |
d1806f6a | 172 | return PTR_ERR(essiv_tfm); |
1da177e4 | 173 | } |
d1806f6a HX |
174 | if (crypto_cipher_blocksize(essiv_tfm) != |
175 | crypto_blkcipher_ivsize(cc->tfm)) { | |
72d94861 | 176 | ti->error = "Block size of ESSIV cipher does " |
1da177e4 | 177 | "not match IV size of block cipher"; |
d1806f6a | 178 | crypto_free_cipher(essiv_tfm); |
1da177e4 LT |
179 | kfree(salt); |
180 | return -EINVAL; | |
181 | } | |
d1806f6a HX |
182 | err = crypto_cipher_setkey(essiv_tfm, salt, saltsize); |
183 | if (err) { | |
72d94861 | 184 | ti->error = "Failed to set key for ESSIV cipher"; |
d1806f6a | 185 | crypto_free_cipher(essiv_tfm); |
1da177e4 | 186 | kfree(salt); |
d1806f6a | 187 | return err; |
1da177e4 LT |
188 | } |
189 | kfree(salt); | |
190 | ||
d1806f6a | 191 | cc->iv_gen_private = essiv_tfm; |
1da177e4 LT |
192 | return 0; |
193 | } | |
194 | ||
195 | static void crypt_iv_essiv_dtr(struct crypt_config *cc) | |
196 | { | |
d1806f6a | 197 | crypto_free_cipher(cc->iv_gen_private); |
1da177e4 LT |
198 | cc->iv_gen_private = NULL; |
199 | } | |
200 | ||
201 | static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector) | |
202 | { | |
1da177e4 LT |
203 | memset(iv, 0, cc->iv_size); |
204 | *(u64 *)iv = cpu_to_le64(sector); | |
d1806f6a | 205 | crypto_cipher_encrypt_one(cc->iv_gen_private, iv, iv); |
1da177e4 LT |
206 | return 0; |
207 | } | |
208 | ||
209 | static struct crypt_iv_operations crypt_iv_plain_ops = { | |
210 | .generator = crypt_iv_plain_gen | |
211 | }; | |
212 | ||
213 | static struct crypt_iv_operations crypt_iv_essiv_ops = { | |
214 | .ctr = crypt_iv_essiv_ctr, | |
215 | .dtr = crypt_iv_essiv_dtr, | |
216 | .generator = crypt_iv_essiv_gen | |
217 | }; | |
218 | ||
219 | ||
858119e1 | 220 | static int |
1da177e4 LT |
221 | crypt_convert_scatterlist(struct crypt_config *cc, struct scatterlist *out, |
222 | struct scatterlist *in, unsigned int length, | |
223 | int write, sector_t sector) | |
224 | { | |
225 | u8 iv[cc->iv_size]; | |
d1806f6a HX |
226 | struct blkcipher_desc desc = { |
227 | .tfm = cc->tfm, | |
228 | .info = iv, | |
229 | .flags = CRYPTO_TFM_REQ_MAY_SLEEP, | |
230 | }; | |
1da177e4 LT |
231 | int r; |
232 | ||
233 | if (cc->iv_gen_ops) { | |
234 | r = cc->iv_gen_ops->generator(cc, iv, sector); | |
235 | if (r < 0) | |
236 | return r; | |
237 | ||
238 | if (write) | |
d1806f6a | 239 | r = crypto_blkcipher_encrypt_iv(&desc, out, in, length); |
1da177e4 | 240 | else |
d1806f6a | 241 | r = crypto_blkcipher_decrypt_iv(&desc, out, in, length); |
1da177e4 LT |
242 | } else { |
243 | if (write) | |
d1806f6a | 244 | r = crypto_blkcipher_encrypt(&desc, out, in, length); |
1da177e4 | 245 | else |
d1806f6a | 246 | r = crypto_blkcipher_decrypt(&desc, out, in, length); |
1da177e4 LT |
247 | } |
248 | ||
249 | return r; | |
250 | } | |
251 | ||
252 | static void | |
253 | crypt_convert_init(struct crypt_config *cc, struct convert_context *ctx, | |
254 | struct bio *bio_out, struct bio *bio_in, | |
255 | sector_t sector, int write) | |
256 | { | |
257 | ctx->bio_in = bio_in; | |
258 | ctx->bio_out = bio_out; | |
259 | ctx->offset_in = 0; | |
260 | ctx->offset_out = 0; | |
261 | ctx->idx_in = bio_in ? bio_in->bi_idx : 0; | |
262 | ctx->idx_out = bio_out ? bio_out->bi_idx : 0; | |
263 | ctx->sector = sector + cc->iv_offset; | |
264 | ctx->write = write; | |
265 | } | |
266 | ||
267 | /* | |
268 | * Encrypt / decrypt data from one bio to another one (can be the same one) | |
269 | */ | |
270 | static int crypt_convert(struct crypt_config *cc, | |
271 | struct convert_context *ctx) | |
272 | { | |
273 | int r = 0; | |
274 | ||
275 | while(ctx->idx_in < ctx->bio_in->bi_vcnt && | |
276 | ctx->idx_out < ctx->bio_out->bi_vcnt) { | |
277 | struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in); | |
278 | struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out); | |
279 | struct scatterlist sg_in = { | |
280 | .page = bv_in->bv_page, | |
281 | .offset = bv_in->bv_offset + ctx->offset_in, | |
282 | .length = 1 << SECTOR_SHIFT | |
283 | }; | |
284 | struct scatterlist sg_out = { | |
285 | .page = bv_out->bv_page, | |
286 | .offset = bv_out->bv_offset + ctx->offset_out, | |
287 | .length = 1 << SECTOR_SHIFT | |
288 | }; | |
289 | ||
290 | ctx->offset_in += sg_in.length; | |
291 | if (ctx->offset_in >= bv_in->bv_len) { | |
292 | ctx->offset_in = 0; | |
293 | ctx->idx_in++; | |
294 | } | |
295 | ||
296 | ctx->offset_out += sg_out.length; | |
297 | if (ctx->offset_out >= bv_out->bv_len) { | |
298 | ctx->offset_out = 0; | |
299 | ctx->idx_out++; | |
300 | } | |
301 | ||
302 | r = crypt_convert_scatterlist(cc, &sg_out, &sg_in, sg_in.length, | |
303 | ctx->write, ctx->sector); | |
304 | if (r < 0) | |
305 | break; | |
306 | ||
307 | ctx->sector++; | |
308 | } | |
309 | ||
310 | return r; | |
311 | } | |
312 | ||
313 | /* | |
314 | * Generate a new unfragmented bio with the given size | |
315 | * This should never violate the device limitations | |
316 | * May return a smaller bio when running out of pages | |
317 | */ | |
318 | static struct bio * | |
319 | crypt_alloc_buffer(struct crypt_config *cc, unsigned int size, | |
320 | struct bio *base_bio, unsigned int *bio_vec_idx) | |
321 | { | |
322 | struct bio *bio; | |
323 | unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
b4e3ca1a | 324 | gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM; |
1da177e4 LT |
325 | unsigned int i; |
326 | ||
327 | /* | |
bd53b714 NP |
328 | * Use __GFP_NOMEMALLOC to tell the VM to act less aggressively and |
329 | * to fail earlier. This is not necessary but increases throughput. | |
1da177e4 LT |
330 | * FIXME: Is this really intelligent? |
331 | */ | |
1da177e4 | 332 | if (base_bio) |
bd53b714 | 333 | bio = bio_clone(base_bio, GFP_NOIO|__GFP_NOMEMALLOC); |
1da177e4 | 334 | else |
bd53b714 NP |
335 | bio = bio_alloc(GFP_NOIO|__GFP_NOMEMALLOC, nr_iovecs); |
336 | if (!bio) | |
1da177e4 | 337 | return NULL; |
1da177e4 LT |
338 | |
339 | /* if the last bio was not complete, continue where that one ended */ | |
340 | bio->bi_idx = *bio_vec_idx; | |
341 | bio->bi_vcnt = *bio_vec_idx; | |
342 | bio->bi_size = 0; | |
343 | bio->bi_flags &= ~(1 << BIO_SEG_VALID); | |
344 | ||
345 | /* bio->bi_idx pages have already been allocated */ | |
346 | size -= bio->bi_idx * PAGE_SIZE; | |
347 | ||
348 | for(i = bio->bi_idx; i < nr_iovecs; i++) { | |
349 | struct bio_vec *bv = bio_iovec_idx(bio, i); | |
350 | ||
351 | bv->bv_page = mempool_alloc(cc->page_pool, gfp_mask); | |
352 | if (!bv->bv_page) | |
353 | break; | |
354 | ||
355 | /* | |
356 | * if additional pages cannot be allocated without waiting, | |
357 | * return a partially allocated bio, the caller will then try | |
358 | * to allocate additional bios while submitting this partial bio | |
359 | */ | |
360 | if ((i - bio->bi_idx) == (MIN_BIO_PAGES - 1)) | |
361 | gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT; | |
362 | ||
363 | bv->bv_offset = 0; | |
364 | if (size > PAGE_SIZE) | |
365 | bv->bv_len = PAGE_SIZE; | |
366 | else | |
367 | bv->bv_len = size; | |
368 | ||
369 | bio->bi_size += bv->bv_len; | |
370 | bio->bi_vcnt++; | |
371 | size -= bv->bv_len; | |
372 | } | |
373 | ||
1da177e4 LT |
374 | if (!bio->bi_size) { |
375 | bio_put(bio); | |
376 | return NULL; | |
377 | } | |
378 | ||
379 | /* | |
380 | * Remember the last bio_vec allocated to be able | |
381 | * to correctly continue after the splitting. | |
382 | */ | |
383 | *bio_vec_idx = bio->bi_vcnt; | |
384 | ||
385 | return bio; | |
386 | } | |
387 | ||
388 | static void crypt_free_buffer_pages(struct crypt_config *cc, | |
389 | struct bio *bio, unsigned int bytes) | |
390 | { | |
391 | unsigned int i, start, end; | |
392 | struct bio_vec *bv; | |
393 | ||
394 | /* | |
395 | * This is ugly, but Jens Axboe thinks that using bi_idx in the | |
396 | * endio function is too dangerous at the moment, so I calculate the | |
397 | * correct position using bi_vcnt and bi_size. | |
398 | * The bv_offset and bv_len fields might already be modified but we | |
399 | * know that we always allocated whole pages. | |
400 | * A fix to the bi_idx issue in the kernel is in the works, so | |
401 | * we will hopefully be able to revert to the cleaner solution soon. | |
402 | */ | |
403 | i = bio->bi_vcnt - 1; | |
404 | bv = bio_iovec_idx(bio, i); | |
405 | end = (i << PAGE_SHIFT) + (bv->bv_offset + bv->bv_len) - bio->bi_size; | |
406 | start = end - bytes; | |
407 | ||
408 | start >>= PAGE_SHIFT; | |
409 | if (!bio->bi_size) | |
410 | end = bio->bi_vcnt; | |
411 | else | |
412 | end >>= PAGE_SHIFT; | |
413 | ||
414 | for(i = start; i < end; i++) { | |
415 | bv = bio_iovec_idx(bio, i); | |
416 | BUG_ON(!bv->bv_page); | |
417 | mempool_free(bv->bv_page, cc->page_pool); | |
418 | bv->bv_page = NULL; | |
419 | } | |
420 | } | |
421 | ||
422 | /* | |
423 | * One of the bios was finished. Check for completion of | |
424 | * the whole request and correctly clean up the buffer. | |
425 | */ | |
426 | static void dec_pending(struct crypt_io *io, int error) | |
427 | { | |
428 | struct crypt_config *cc = (struct crypt_config *) io->target->private; | |
429 | ||
430 | if (error < 0) | |
431 | io->error = error; | |
432 | ||
433 | if (!atomic_dec_and_test(&io->pending)) | |
434 | return; | |
435 | ||
436 | if (io->first_clone) | |
437 | bio_put(io->first_clone); | |
438 | ||
439 | bio_endio(io->bio, io->bio->bi_size, io->error); | |
440 | ||
441 | mempool_free(io, cc->io_pool); | |
442 | } | |
443 | ||
444 | /* | |
445 | * kcryptd: | |
446 | * | |
447 | * Needed because it would be very unwise to do decryption in an | |
448 | * interrupt context, so bios returning from read requests get | |
449 | * queued here. | |
450 | */ | |
451 | static struct workqueue_struct *_kcryptd_workqueue; | |
452 | ||
453 | static void kcryptd_do_work(void *data) | |
454 | { | |
455 | struct crypt_io *io = (struct crypt_io *) data; | |
456 | struct crypt_config *cc = (struct crypt_config *) io->target->private; | |
457 | struct convert_context ctx; | |
458 | int r; | |
459 | ||
460 | crypt_convert_init(cc, &ctx, io->bio, io->bio, | |
461 | io->bio->bi_sector - io->target->begin, 0); | |
462 | r = crypt_convert(cc, &ctx); | |
463 | ||
464 | dec_pending(io, r); | |
465 | } | |
466 | ||
467 | static void kcryptd_queue_io(struct crypt_io *io) | |
468 | { | |
469 | INIT_WORK(&io->work, kcryptd_do_work, io); | |
470 | queue_work(_kcryptd_workqueue, &io->work); | |
471 | } | |
472 | ||
473 | /* | |
474 | * Decode key from its hex representation | |
475 | */ | |
476 | static int crypt_decode_key(u8 *key, char *hex, unsigned int size) | |
477 | { | |
478 | char buffer[3]; | |
479 | char *endp; | |
480 | unsigned int i; | |
481 | ||
482 | buffer[2] = '\0'; | |
483 | ||
484 | for(i = 0; i < size; i++) { | |
485 | buffer[0] = *hex++; | |
486 | buffer[1] = *hex++; | |
487 | ||
488 | key[i] = (u8)simple_strtoul(buffer, &endp, 16); | |
489 | ||
490 | if (endp != &buffer[2]) | |
491 | return -EINVAL; | |
492 | } | |
493 | ||
494 | if (*hex != '\0') | |
495 | return -EINVAL; | |
496 | ||
497 | return 0; | |
498 | } | |
499 | ||
500 | /* | |
501 | * Encode key into its hex representation | |
502 | */ | |
503 | static void crypt_encode_key(char *hex, u8 *key, unsigned int size) | |
504 | { | |
505 | unsigned int i; | |
506 | ||
507 | for(i = 0; i < size; i++) { | |
508 | sprintf(hex, "%02x", *key); | |
509 | hex += 2; | |
510 | key++; | |
511 | } | |
512 | } | |
513 | ||
e48d4bbf MB |
514 | static int crypt_set_key(struct crypt_config *cc, char *key) |
515 | { | |
516 | unsigned key_size = strlen(key) >> 1; | |
517 | ||
518 | if (cc->key_size && cc->key_size != key_size) | |
519 | return -EINVAL; | |
520 | ||
521 | cc->key_size = key_size; /* initial settings */ | |
522 | ||
523 | if ((!key_size && strcmp(key, "-")) || | |
524 | (key_size && crypt_decode_key(cc->key, key, key_size) < 0)) | |
525 | return -EINVAL; | |
526 | ||
527 | set_bit(DM_CRYPT_KEY_VALID, &cc->flags); | |
528 | ||
529 | return 0; | |
530 | } | |
531 | ||
532 | static int crypt_wipe_key(struct crypt_config *cc) | |
533 | { | |
534 | clear_bit(DM_CRYPT_KEY_VALID, &cc->flags); | |
535 | memset(&cc->key, 0, cc->key_size * sizeof(u8)); | |
536 | return 0; | |
537 | } | |
538 | ||
1da177e4 LT |
539 | /* |
540 | * Construct an encryption mapping: | |
541 | * <cipher> <key> <iv_offset> <dev_path> <start> | |
542 | */ | |
543 | static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
544 | { | |
545 | struct crypt_config *cc; | |
d1806f6a | 546 | struct crypto_blkcipher *tfm; |
1da177e4 LT |
547 | char *tmp; |
548 | char *cipher; | |
549 | char *chainmode; | |
550 | char *ivmode; | |
551 | char *ivopts; | |
1da177e4 | 552 | unsigned int key_size; |
4ee218cd | 553 | unsigned long long tmpll; |
1da177e4 LT |
554 | |
555 | if (argc != 5) { | |
72d94861 | 556 | ti->error = "Not enough arguments"; |
1da177e4 LT |
557 | return -EINVAL; |
558 | } | |
559 | ||
560 | tmp = argv[0]; | |
561 | cipher = strsep(&tmp, "-"); | |
562 | chainmode = strsep(&tmp, "-"); | |
563 | ivopts = strsep(&tmp, "-"); | |
564 | ivmode = strsep(&ivopts, ":"); | |
565 | ||
566 | if (tmp) | |
72d94861 | 567 | DMWARN("Unexpected additional cipher options"); |
1da177e4 LT |
568 | |
569 | key_size = strlen(argv[1]) >> 1; | |
570 | ||
e48d4bbf | 571 | cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL); |
1da177e4 LT |
572 | if (cc == NULL) { |
573 | ti->error = | |
72d94861 | 574 | "Cannot allocate transparent encryption context"; |
1da177e4 LT |
575 | return -ENOMEM; |
576 | } | |
577 | ||
e48d4bbf | 578 | if (crypt_set_key(cc, argv[1])) { |
72d94861 | 579 | ti->error = "Error decoding key"; |
1da177e4 LT |
580 | goto bad1; |
581 | } | |
582 | ||
583 | /* Compatiblity mode for old dm-crypt cipher strings */ | |
584 | if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) { | |
585 | chainmode = "cbc"; | |
586 | ivmode = "plain"; | |
587 | } | |
588 | ||
d1806f6a HX |
589 | if (strcmp(chainmode, "ecb") && !ivmode) { |
590 | ti->error = "This chaining mode requires an IV mechanism"; | |
1da177e4 LT |
591 | goto bad1; |
592 | } | |
593 | ||
d1806f6a HX |
594 | if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)", chainmode, |
595 | cipher) >= CRYPTO_MAX_ALG_NAME) { | |
596 | ti->error = "Chain mode + cipher name is too long"; | |
1da177e4 LT |
597 | goto bad1; |
598 | } | |
599 | ||
d1806f6a HX |
600 | tfm = crypto_alloc_blkcipher(cc->cipher, 0, CRYPTO_ALG_ASYNC); |
601 | if (IS_ERR(tfm)) { | |
72d94861 | 602 | ti->error = "Error allocating crypto tfm"; |
1da177e4 LT |
603 | goto bad1; |
604 | } | |
1da177e4 | 605 | |
d1806f6a HX |
606 | strcpy(cc->cipher, cipher); |
607 | strcpy(cc->chainmode, chainmode); | |
1da177e4 LT |
608 | cc->tfm = tfm; |
609 | ||
610 | /* | |
611 | * Choose ivmode. Valid modes: "plain", "essiv:<esshash>". | |
612 | * See comments at iv code | |
613 | */ | |
614 | ||
615 | if (ivmode == NULL) | |
616 | cc->iv_gen_ops = NULL; | |
617 | else if (strcmp(ivmode, "plain") == 0) | |
618 | cc->iv_gen_ops = &crypt_iv_plain_ops; | |
619 | else if (strcmp(ivmode, "essiv") == 0) | |
620 | cc->iv_gen_ops = &crypt_iv_essiv_ops; | |
621 | else { | |
72d94861 | 622 | ti->error = "Invalid IV mode"; |
1da177e4 LT |
623 | goto bad2; |
624 | } | |
625 | ||
626 | if (cc->iv_gen_ops && cc->iv_gen_ops->ctr && | |
627 | cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0) | |
628 | goto bad2; | |
629 | ||
d1806f6a HX |
630 | cc->iv_size = crypto_blkcipher_ivsize(tfm); |
631 | if (cc->iv_size) | |
1da177e4 | 632 | /* at least a 64 bit sector number should fit in our buffer */ |
d1806f6a | 633 | cc->iv_size = max(cc->iv_size, |
1da177e4 LT |
634 | (unsigned int)(sizeof(u64) / sizeof(u8))); |
635 | else { | |
1da177e4 | 636 | if (cc->iv_gen_ops) { |
72d94861 | 637 | DMWARN("Selected cipher does not support IVs"); |
1da177e4 LT |
638 | if (cc->iv_gen_ops->dtr) |
639 | cc->iv_gen_ops->dtr(cc); | |
640 | cc->iv_gen_ops = NULL; | |
641 | } | |
642 | } | |
643 | ||
93d2341c | 644 | cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool); |
1da177e4 | 645 | if (!cc->io_pool) { |
72d94861 | 646 | ti->error = "Cannot allocate crypt io mempool"; |
1da177e4 LT |
647 | goto bad3; |
648 | } | |
649 | ||
a19b27ce | 650 | cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0); |
1da177e4 | 651 | if (!cc->page_pool) { |
72d94861 | 652 | ti->error = "Cannot allocate page mempool"; |
1da177e4 LT |
653 | goto bad4; |
654 | } | |
655 | ||
d1806f6a | 656 | if (crypto_blkcipher_setkey(tfm, cc->key, key_size) < 0) { |
72d94861 | 657 | ti->error = "Error setting key"; |
1da177e4 LT |
658 | goto bad5; |
659 | } | |
660 | ||
4ee218cd | 661 | if (sscanf(argv[2], "%llu", &tmpll) != 1) { |
72d94861 | 662 | ti->error = "Invalid iv_offset sector"; |
1da177e4 LT |
663 | goto bad5; |
664 | } | |
4ee218cd | 665 | cc->iv_offset = tmpll; |
1da177e4 | 666 | |
4ee218cd | 667 | if (sscanf(argv[4], "%llu", &tmpll) != 1) { |
72d94861 | 668 | ti->error = "Invalid device sector"; |
1da177e4 LT |
669 | goto bad5; |
670 | } | |
4ee218cd | 671 | cc->start = tmpll; |
1da177e4 LT |
672 | |
673 | if (dm_get_device(ti, argv[3], cc->start, ti->len, | |
674 | dm_table_get_mode(ti->table), &cc->dev)) { | |
72d94861 | 675 | ti->error = "Device lookup failed"; |
1da177e4 LT |
676 | goto bad5; |
677 | } | |
678 | ||
679 | if (ivmode && cc->iv_gen_ops) { | |
680 | if (ivopts) | |
681 | *(ivopts - 1) = ':'; | |
682 | cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL); | |
683 | if (!cc->iv_mode) { | |
72d94861 | 684 | ti->error = "Error kmallocing iv_mode string"; |
1da177e4 LT |
685 | goto bad5; |
686 | } | |
687 | strcpy(cc->iv_mode, ivmode); | |
688 | } else | |
689 | cc->iv_mode = NULL; | |
690 | ||
691 | ti->private = cc; | |
692 | return 0; | |
693 | ||
694 | bad5: | |
695 | mempool_destroy(cc->page_pool); | |
696 | bad4: | |
697 | mempool_destroy(cc->io_pool); | |
698 | bad3: | |
699 | if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) | |
700 | cc->iv_gen_ops->dtr(cc); | |
701 | bad2: | |
d1806f6a | 702 | crypto_free_blkcipher(tfm); |
1da177e4 | 703 | bad1: |
9d3520a3 SR |
704 | /* Must zero key material before freeing */ |
705 | memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8)); | |
1da177e4 LT |
706 | kfree(cc); |
707 | return -EINVAL; | |
708 | } | |
709 | ||
710 | static void crypt_dtr(struct dm_target *ti) | |
711 | { | |
712 | struct crypt_config *cc = (struct crypt_config *) ti->private; | |
713 | ||
714 | mempool_destroy(cc->page_pool); | |
715 | mempool_destroy(cc->io_pool); | |
716 | ||
990a8baf | 717 | kfree(cc->iv_mode); |
1da177e4 LT |
718 | if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) |
719 | cc->iv_gen_ops->dtr(cc); | |
d1806f6a | 720 | crypto_free_blkcipher(cc->tfm); |
1da177e4 | 721 | dm_put_device(ti, cc->dev); |
9d3520a3 SR |
722 | |
723 | /* Must zero key material before freeing */ | |
724 | memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8)); | |
1da177e4 LT |
725 | kfree(cc); |
726 | } | |
727 | ||
728 | static int crypt_endio(struct bio *bio, unsigned int done, int error) | |
729 | { | |
730 | struct crypt_io *io = (struct crypt_io *) bio->bi_private; | |
731 | struct crypt_config *cc = (struct crypt_config *) io->target->private; | |
732 | ||
733 | if (bio_data_dir(bio) == WRITE) { | |
734 | /* | |
735 | * free the processed pages, even if | |
736 | * it's only a partially completed write | |
737 | */ | |
738 | crypt_free_buffer_pages(cc, bio, done); | |
739 | } | |
740 | ||
741 | if (bio->bi_size) | |
742 | return 1; | |
743 | ||
744 | bio_put(bio); | |
745 | ||
746 | /* | |
747 | * successful reads are decrypted by the worker thread | |
748 | */ | |
749 | if ((bio_data_dir(bio) == READ) | |
750 | && bio_flagged(bio, BIO_UPTODATE)) { | |
751 | kcryptd_queue_io(io); | |
752 | return 0; | |
753 | } | |
754 | ||
755 | dec_pending(io, error); | |
756 | return error; | |
757 | } | |
758 | ||
759 | static inline struct bio * | |
760 | crypt_clone(struct crypt_config *cc, struct crypt_io *io, struct bio *bio, | |
761 | sector_t sector, unsigned int *bvec_idx, | |
762 | struct convert_context *ctx) | |
763 | { | |
764 | struct bio *clone; | |
765 | ||
766 | if (bio_data_dir(bio) == WRITE) { | |
767 | clone = crypt_alloc_buffer(cc, bio->bi_size, | |
768 | io->first_clone, bvec_idx); | |
769 | if (clone) { | |
770 | ctx->bio_out = clone; | |
771 | if (crypt_convert(cc, ctx) < 0) { | |
772 | crypt_free_buffer_pages(cc, clone, | |
773 | clone->bi_size); | |
774 | bio_put(clone); | |
775 | return NULL; | |
776 | } | |
777 | } | |
778 | } else { | |
779 | /* | |
780 | * The block layer might modify the bvec array, so always | |
781 | * copy the required bvecs because we need the original | |
782 | * one in order to decrypt the whole bio data *afterwards*. | |
783 | */ | |
784 | clone = bio_alloc(GFP_NOIO, bio_segments(bio)); | |
785 | if (clone) { | |
786 | clone->bi_idx = 0; | |
787 | clone->bi_vcnt = bio_segments(bio); | |
788 | clone->bi_size = bio->bi_size; | |
789 | memcpy(clone->bi_io_vec, bio_iovec(bio), | |
790 | sizeof(struct bio_vec) * clone->bi_vcnt); | |
791 | } | |
792 | } | |
793 | ||
794 | if (!clone) | |
795 | return NULL; | |
796 | ||
797 | clone->bi_private = io; | |
798 | clone->bi_end_io = crypt_endio; | |
799 | clone->bi_bdev = cc->dev->bdev; | |
800 | clone->bi_sector = cc->start + sector; | |
801 | clone->bi_rw = bio->bi_rw; | |
802 | ||
803 | return clone; | |
804 | } | |
805 | ||
806 | static int crypt_map(struct dm_target *ti, struct bio *bio, | |
807 | union map_info *map_context) | |
808 | { | |
809 | struct crypt_config *cc = (struct crypt_config *) ti->private; | |
e48d4bbf | 810 | struct crypt_io *io; |
1da177e4 LT |
811 | struct convert_context ctx; |
812 | struct bio *clone; | |
813 | unsigned int remaining = bio->bi_size; | |
814 | sector_t sector = bio->bi_sector - ti->begin; | |
815 | unsigned int bvec_idx = 0; | |
816 | ||
e48d4bbf | 817 | io = mempool_alloc(cc->io_pool, GFP_NOIO); |
1da177e4 LT |
818 | io->target = ti; |
819 | io->bio = bio; | |
820 | io->first_clone = NULL; | |
821 | io->error = 0; | |
822 | atomic_set(&io->pending, 1); /* hold a reference */ | |
823 | ||
824 | if (bio_data_dir(bio) == WRITE) | |
825 | crypt_convert_init(cc, &ctx, NULL, bio, sector, 1); | |
826 | ||
827 | /* | |
828 | * The allocated buffers can be smaller than the whole bio, | |
829 | * so repeat the whole process until all the data can be handled. | |
830 | */ | |
831 | while (remaining) { | |
832 | clone = crypt_clone(cc, io, bio, sector, &bvec_idx, &ctx); | |
833 | if (!clone) | |
834 | goto cleanup; | |
835 | ||
836 | if (!io->first_clone) { | |
837 | /* | |
838 | * hold a reference to the first clone, because it | |
839 | * holds the bio_vec array and that can't be freed | |
840 | * before all other clones are released | |
841 | */ | |
842 | bio_get(clone); | |
843 | io->first_clone = clone; | |
844 | } | |
845 | atomic_inc(&io->pending); | |
846 | ||
847 | remaining -= clone->bi_size; | |
848 | sector += bio_sectors(clone); | |
849 | ||
850 | generic_make_request(clone); | |
851 | ||
852 | /* out of memory -> run queues */ | |
853 | if (remaining) | |
854 | blk_congestion_wait(bio_data_dir(clone), HZ/100); | |
855 | } | |
856 | ||
857 | /* drop reference, clones could have returned before we reach this */ | |
858 | dec_pending(io, 0); | |
859 | return 0; | |
860 | ||
861 | cleanup: | |
862 | if (io->first_clone) { | |
863 | dec_pending(io, -ENOMEM); | |
864 | return 0; | |
865 | } | |
866 | ||
867 | /* if no bio has been dispatched yet, we can directly return the error */ | |
868 | mempool_free(io, cc->io_pool); | |
869 | return -ENOMEM; | |
870 | } | |
871 | ||
872 | static int crypt_status(struct dm_target *ti, status_type_t type, | |
873 | char *result, unsigned int maxlen) | |
874 | { | |
875 | struct crypt_config *cc = (struct crypt_config *) ti->private; | |
876 | const char *cipher; | |
877 | const char *chainmode = NULL; | |
878 | unsigned int sz = 0; | |
879 | ||
880 | switch (type) { | |
881 | case STATUSTYPE_INFO: | |
882 | result[0] = '\0'; | |
883 | break; | |
884 | ||
885 | case STATUSTYPE_TABLE: | |
d1806f6a | 886 | cipher = crypto_blkcipher_name(cc->tfm); |
1da177e4 | 887 | |
d1806f6a | 888 | chainmode = cc->chainmode; |
1da177e4 LT |
889 | |
890 | if (cc->iv_mode) | |
891 | DMEMIT("%s-%s-%s ", cipher, chainmode, cc->iv_mode); | |
892 | else | |
893 | DMEMIT("%s-%s ", cipher, chainmode); | |
894 | ||
895 | if (cc->key_size > 0) { | |
896 | if ((maxlen - sz) < ((cc->key_size << 1) + 1)) | |
897 | return -ENOMEM; | |
898 | ||
899 | crypt_encode_key(result + sz, cc->key, cc->key_size); | |
900 | sz += cc->key_size << 1; | |
901 | } else { | |
902 | if (sz >= maxlen) | |
903 | return -ENOMEM; | |
904 | result[sz++] = '-'; | |
905 | } | |
906 | ||
4ee218cd AM |
907 | DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset, |
908 | cc->dev->name, (unsigned long long)cc->start); | |
1da177e4 LT |
909 | break; |
910 | } | |
911 | return 0; | |
912 | } | |
913 | ||
e48d4bbf MB |
914 | static void crypt_postsuspend(struct dm_target *ti) |
915 | { | |
916 | struct crypt_config *cc = ti->private; | |
917 | ||
918 | set_bit(DM_CRYPT_SUSPENDED, &cc->flags); | |
919 | } | |
920 | ||
921 | static int crypt_preresume(struct dm_target *ti) | |
922 | { | |
923 | struct crypt_config *cc = ti->private; | |
924 | ||
925 | if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) { | |
926 | DMERR("aborting resume - crypt key is not set."); | |
927 | return -EAGAIN; | |
928 | } | |
929 | ||
930 | return 0; | |
931 | } | |
932 | ||
933 | static void crypt_resume(struct dm_target *ti) | |
934 | { | |
935 | struct crypt_config *cc = ti->private; | |
936 | ||
937 | clear_bit(DM_CRYPT_SUSPENDED, &cc->flags); | |
938 | } | |
939 | ||
940 | /* Message interface | |
941 | * key set <key> | |
942 | * key wipe | |
943 | */ | |
944 | static int crypt_message(struct dm_target *ti, unsigned argc, char **argv) | |
945 | { | |
946 | struct crypt_config *cc = ti->private; | |
947 | ||
948 | if (argc < 2) | |
949 | goto error; | |
950 | ||
951 | if (!strnicmp(argv[0], MESG_STR("key"))) { | |
952 | if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) { | |
953 | DMWARN("not suspended during key manipulation."); | |
954 | return -EINVAL; | |
955 | } | |
956 | if (argc == 3 && !strnicmp(argv[1], MESG_STR("set"))) | |
957 | return crypt_set_key(cc, argv[2]); | |
958 | if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe"))) | |
959 | return crypt_wipe_key(cc); | |
960 | } | |
961 | ||
962 | error: | |
963 | DMWARN("unrecognised message received."); | |
964 | return -EINVAL; | |
965 | } | |
966 | ||
1da177e4 LT |
967 | static struct target_type crypt_target = { |
968 | .name = "crypt", | |
e48d4bbf | 969 | .version= {1, 2, 0}, |
1da177e4 LT |
970 | .module = THIS_MODULE, |
971 | .ctr = crypt_ctr, | |
972 | .dtr = crypt_dtr, | |
973 | .map = crypt_map, | |
974 | .status = crypt_status, | |
e48d4bbf MB |
975 | .postsuspend = crypt_postsuspend, |
976 | .preresume = crypt_preresume, | |
977 | .resume = crypt_resume, | |
978 | .message = crypt_message, | |
1da177e4 LT |
979 | }; |
980 | ||
981 | static int __init dm_crypt_init(void) | |
982 | { | |
983 | int r; | |
984 | ||
985 | _crypt_io_pool = kmem_cache_create("dm-crypt_io", | |
986 | sizeof(struct crypt_io), | |
987 | 0, 0, NULL, NULL); | |
988 | if (!_crypt_io_pool) | |
989 | return -ENOMEM; | |
990 | ||
991 | _kcryptd_workqueue = create_workqueue("kcryptd"); | |
992 | if (!_kcryptd_workqueue) { | |
993 | r = -ENOMEM; | |
72d94861 | 994 | DMERR("couldn't create kcryptd"); |
1da177e4 LT |
995 | goto bad1; |
996 | } | |
997 | ||
998 | r = dm_register_target(&crypt_target); | |
999 | if (r < 0) { | |
72d94861 | 1000 | DMERR("register failed %d", r); |
1da177e4 LT |
1001 | goto bad2; |
1002 | } | |
1003 | ||
1004 | return 0; | |
1005 | ||
1006 | bad2: | |
1007 | destroy_workqueue(_kcryptd_workqueue); | |
1008 | bad1: | |
1009 | kmem_cache_destroy(_crypt_io_pool); | |
1010 | return r; | |
1011 | } | |
1012 | ||
1013 | static void __exit dm_crypt_exit(void) | |
1014 | { | |
1015 | int r = dm_unregister_target(&crypt_target); | |
1016 | ||
1017 | if (r < 0) | |
72d94861 | 1018 | DMERR("unregister failed %d", r); |
1da177e4 LT |
1019 | |
1020 | destroy_workqueue(_kcryptd_workqueue); | |
1021 | kmem_cache_destroy(_crypt_io_pool); | |
1022 | } | |
1023 | ||
1024 | module_init(dm_crypt_init); | |
1025 | module_exit(dm_crypt_exit); | |
1026 | ||
1027 | MODULE_AUTHOR("Christophe Saout <christophe@saout.de>"); | |
1028 | MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption"); | |
1029 | MODULE_LICENSE("GPL"); |