Commit | Line | Data |
---|---|---|
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> | |
3fcfab16 | 19 | #include <linux/backing-dev.h> |
1da177e4 | 20 | #include <asm/atomic.h> |
378f058c | 21 | #include <linux/scatterlist.h> |
1da177e4 LT |
22 | #include <asm/page.h> |
23 | ||
24 | #include "dm.h" | |
25 | ||
72d94861 | 26 | #define DM_MSG_PREFIX "crypt" |
e48d4bbf | 27 | #define MESG_STR(x) x, sizeof(x) |
1da177e4 LT |
28 | |
29 | /* | |
30 | * per bio private data | |
31 | */ | |
32 | struct crypt_io { | |
33 | struct dm_target *target; | |
8b004457 | 34 | struct bio *base_bio; |
1da177e4 LT |
35 | struct bio *first_clone; |
36 | struct work_struct work; | |
37 | atomic_t pending; | |
38 | int error; | |
23541d2d | 39 | int post_process; |
1da177e4 LT |
40 | }; |
41 | ||
42 | /* | |
43 | * context holding the current state of a multi-part conversion | |
44 | */ | |
45 | struct convert_context { | |
46 | struct bio *bio_in; | |
47 | struct bio *bio_out; | |
48 | unsigned int offset_in; | |
49 | unsigned int offset_out; | |
50 | unsigned int idx_in; | |
51 | unsigned int idx_out; | |
52 | sector_t sector; | |
53 | int write; | |
54 | }; | |
55 | ||
56 | struct crypt_config; | |
57 | ||
58 | struct crypt_iv_operations { | |
59 | int (*ctr)(struct crypt_config *cc, struct dm_target *ti, | |
60 | const char *opts); | |
61 | void (*dtr)(struct crypt_config *cc); | |
62 | const char *(*status)(struct crypt_config *cc); | |
63 | int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector); | |
64 | }; | |
65 | ||
66 | /* | |
67 | * Crypt: maps a linear range of a block device | |
68 | * and encrypts / decrypts at the same time. | |
69 | */ | |
e48d4bbf | 70 | enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID }; |
1da177e4 LT |
71 | struct crypt_config { |
72 | struct dm_dev *dev; | |
73 | sector_t start; | |
74 | ||
75 | /* | |
76 | * pool for per bio private data and | |
77 | * for encryption buffer pages | |
78 | */ | |
79 | mempool_t *io_pool; | |
80 | mempool_t *page_pool; | |
6a24c718 | 81 | struct bio_set *bs; |
1da177e4 LT |
82 | |
83 | /* | |
84 | * crypto related data | |
85 | */ | |
86 | struct crypt_iv_operations *iv_gen_ops; | |
87 | char *iv_mode; | |
d1806f6a | 88 | struct crypto_cipher *iv_gen_private; |
1da177e4 LT |
89 | sector_t iv_offset; |
90 | unsigned int iv_size; | |
91 | ||
d1806f6a HX |
92 | char cipher[CRYPTO_MAX_ALG_NAME]; |
93 | char chainmode[CRYPTO_MAX_ALG_NAME]; | |
94 | struct crypto_blkcipher *tfm; | |
e48d4bbf | 95 | unsigned long flags; |
1da177e4 LT |
96 | unsigned int key_size; |
97 | u8 key[0]; | |
98 | }; | |
99 | ||
6a24c718 | 100 | #define MIN_IOS 16 |
1da177e4 LT |
101 | #define MIN_POOL_PAGES 32 |
102 | #define MIN_BIO_PAGES 8 | |
103 | ||
104 | static kmem_cache_t *_crypt_io_pool; | |
105 | ||
1da177e4 LT |
106 | /* |
107 | * Different IV generation algorithms: | |
108 | * | |
3c164bd8 | 109 | * plain: the initial vector is the 32-bit little-endian version of the sector |
1da177e4 LT |
110 | * number, padded with zeros if neccessary. |
111 | * | |
3c164bd8 RS |
112 | * essiv: "encrypted sector|salt initial vector", the sector number is |
113 | * encrypted with the bulk cipher using a salt as key. The salt | |
114 | * should be derived from the bulk cipher's key via hashing. | |
1da177e4 LT |
115 | * |
116 | * plumb: unimplemented, see: | |
117 | * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454 | |
118 | */ | |
119 | ||
120 | static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector) | |
121 | { | |
122 | memset(iv, 0, cc->iv_size); | |
123 | *(u32 *)iv = cpu_to_le32(sector & 0xffffffff); | |
124 | ||
125 | return 0; | |
126 | } | |
127 | ||
128 | static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, | |
129 | const char *opts) | |
130 | { | |
d1806f6a | 131 | struct crypto_cipher *essiv_tfm; |
35058687 HX |
132 | struct crypto_hash *hash_tfm; |
133 | struct hash_desc desc; | |
1da177e4 LT |
134 | struct scatterlist sg; |
135 | unsigned int saltsize; | |
136 | u8 *salt; | |
d1806f6a | 137 | int err; |
1da177e4 LT |
138 | |
139 | if (opts == NULL) { | |
72d94861 | 140 | ti->error = "Digest algorithm missing for ESSIV mode"; |
1da177e4 LT |
141 | return -EINVAL; |
142 | } | |
143 | ||
144 | /* Hash the cipher key with the given hash algorithm */ | |
35058687 HX |
145 | hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC); |
146 | if (IS_ERR(hash_tfm)) { | |
72d94861 | 147 | ti->error = "Error initializing ESSIV hash"; |
35058687 | 148 | return PTR_ERR(hash_tfm); |
1da177e4 LT |
149 | } |
150 | ||
35058687 | 151 | saltsize = crypto_hash_digestsize(hash_tfm); |
1da177e4 LT |
152 | salt = kmalloc(saltsize, GFP_KERNEL); |
153 | if (salt == NULL) { | |
72d94861 | 154 | ti->error = "Error kmallocing salt storage in ESSIV"; |
35058687 | 155 | crypto_free_hash(hash_tfm); |
1da177e4 LT |
156 | return -ENOMEM; |
157 | } | |
158 | ||
378f058c | 159 | sg_set_buf(&sg, cc->key, cc->key_size); |
35058687 HX |
160 | desc.tfm = hash_tfm; |
161 | desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; | |
162 | err = crypto_hash_digest(&desc, &sg, cc->key_size, salt); | |
163 | crypto_free_hash(hash_tfm); | |
164 | ||
165 | if (err) { | |
166 | ti->error = "Error calculating hash in ESSIV"; | |
167 | return err; | |
168 | } | |
1da177e4 LT |
169 | |
170 | /* Setup the essiv_tfm with the given salt */ | |
d1806f6a HX |
171 | essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC); |
172 | if (IS_ERR(essiv_tfm)) { | |
72d94861 | 173 | ti->error = "Error allocating crypto tfm for ESSIV"; |
1da177e4 | 174 | kfree(salt); |
d1806f6a | 175 | return PTR_ERR(essiv_tfm); |
1da177e4 | 176 | } |
d1806f6a HX |
177 | if (crypto_cipher_blocksize(essiv_tfm) != |
178 | crypto_blkcipher_ivsize(cc->tfm)) { | |
72d94861 | 179 | ti->error = "Block size of ESSIV cipher does " |
1da177e4 | 180 | "not match IV size of block cipher"; |
d1806f6a | 181 | crypto_free_cipher(essiv_tfm); |
1da177e4 LT |
182 | kfree(salt); |
183 | return -EINVAL; | |
184 | } | |
d1806f6a HX |
185 | err = crypto_cipher_setkey(essiv_tfm, salt, saltsize); |
186 | if (err) { | |
72d94861 | 187 | ti->error = "Failed to set key for ESSIV cipher"; |
d1806f6a | 188 | crypto_free_cipher(essiv_tfm); |
1da177e4 | 189 | kfree(salt); |
d1806f6a | 190 | return err; |
1da177e4 LT |
191 | } |
192 | kfree(salt); | |
193 | ||
d1806f6a | 194 | cc->iv_gen_private = essiv_tfm; |
1da177e4 LT |
195 | return 0; |
196 | } | |
197 | ||
198 | static void crypt_iv_essiv_dtr(struct crypt_config *cc) | |
199 | { | |
d1806f6a | 200 | crypto_free_cipher(cc->iv_gen_private); |
1da177e4 LT |
201 | cc->iv_gen_private = NULL; |
202 | } | |
203 | ||
204 | static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector) | |
205 | { | |
1da177e4 LT |
206 | memset(iv, 0, cc->iv_size); |
207 | *(u64 *)iv = cpu_to_le64(sector); | |
d1806f6a | 208 | crypto_cipher_encrypt_one(cc->iv_gen_private, iv, iv); |
1da177e4 LT |
209 | return 0; |
210 | } | |
211 | ||
212 | static struct crypt_iv_operations crypt_iv_plain_ops = { | |
213 | .generator = crypt_iv_plain_gen | |
214 | }; | |
215 | ||
216 | static struct crypt_iv_operations crypt_iv_essiv_ops = { | |
217 | .ctr = crypt_iv_essiv_ctr, | |
218 | .dtr = crypt_iv_essiv_dtr, | |
219 | .generator = crypt_iv_essiv_gen | |
220 | }; | |
221 | ||
222 | ||
858119e1 | 223 | static int |
1da177e4 LT |
224 | crypt_convert_scatterlist(struct crypt_config *cc, struct scatterlist *out, |
225 | struct scatterlist *in, unsigned int length, | |
226 | int write, sector_t sector) | |
227 | { | |
228 | u8 iv[cc->iv_size]; | |
d1806f6a HX |
229 | struct blkcipher_desc desc = { |
230 | .tfm = cc->tfm, | |
231 | .info = iv, | |
232 | .flags = CRYPTO_TFM_REQ_MAY_SLEEP, | |
233 | }; | |
1da177e4 LT |
234 | int r; |
235 | ||
236 | if (cc->iv_gen_ops) { | |
237 | r = cc->iv_gen_ops->generator(cc, iv, sector); | |
238 | if (r < 0) | |
239 | return r; | |
240 | ||
241 | if (write) | |
d1806f6a | 242 | r = crypto_blkcipher_encrypt_iv(&desc, out, in, length); |
1da177e4 | 243 | else |
d1806f6a | 244 | r = crypto_blkcipher_decrypt_iv(&desc, out, in, length); |
1da177e4 LT |
245 | } else { |
246 | if (write) | |
d1806f6a | 247 | r = crypto_blkcipher_encrypt(&desc, out, in, length); |
1da177e4 | 248 | else |
d1806f6a | 249 | r = crypto_blkcipher_decrypt(&desc, out, in, length); |
1da177e4 LT |
250 | } |
251 | ||
252 | return r; | |
253 | } | |
254 | ||
255 | static void | |
256 | crypt_convert_init(struct crypt_config *cc, struct convert_context *ctx, | |
257 | struct bio *bio_out, struct bio *bio_in, | |
258 | sector_t sector, int write) | |
259 | { | |
260 | ctx->bio_in = bio_in; | |
261 | ctx->bio_out = bio_out; | |
262 | ctx->offset_in = 0; | |
263 | ctx->offset_out = 0; | |
264 | ctx->idx_in = bio_in ? bio_in->bi_idx : 0; | |
265 | ctx->idx_out = bio_out ? bio_out->bi_idx : 0; | |
266 | ctx->sector = sector + cc->iv_offset; | |
267 | ctx->write = write; | |
268 | } | |
269 | ||
270 | /* | |
271 | * Encrypt / decrypt data from one bio to another one (can be the same one) | |
272 | */ | |
273 | static int crypt_convert(struct crypt_config *cc, | |
274 | struct convert_context *ctx) | |
275 | { | |
276 | int r = 0; | |
277 | ||
278 | while(ctx->idx_in < ctx->bio_in->bi_vcnt && | |
279 | ctx->idx_out < ctx->bio_out->bi_vcnt) { | |
280 | struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in); | |
281 | struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out); | |
282 | struct scatterlist sg_in = { | |
283 | .page = bv_in->bv_page, | |
284 | .offset = bv_in->bv_offset + ctx->offset_in, | |
285 | .length = 1 << SECTOR_SHIFT | |
286 | }; | |
287 | struct scatterlist sg_out = { | |
288 | .page = bv_out->bv_page, | |
289 | .offset = bv_out->bv_offset + ctx->offset_out, | |
290 | .length = 1 << SECTOR_SHIFT | |
291 | }; | |
292 | ||
293 | ctx->offset_in += sg_in.length; | |
294 | if (ctx->offset_in >= bv_in->bv_len) { | |
295 | ctx->offset_in = 0; | |
296 | ctx->idx_in++; | |
297 | } | |
298 | ||
299 | ctx->offset_out += sg_out.length; | |
300 | if (ctx->offset_out >= bv_out->bv_len) { | |
301 | ctx->offset_out = 0; | |
302 | ctx->idx_out++; | |
303 | } | |
304 | ||
305 | r = crypt_convert_scatterlist(cc, &sg_out, &sg_in, sg_in.length, | |
306 | ctx->write, ctx->sector); | |
307 | if (r < 0) | |
308 | break; | |
309 | ||
310 | ctx->sector++; | |
311 | } | |
312 | ||
313 | return r; | |
314 | } | |
315 | ||
6a24c718 MB |
316 | static void dm_crypt_bio_destructor(struct bio *bio) |
317 | { | |
318 | struct crypt_io *io = bio->bi_private; | |
319 | struct crypt_config *cc = io->target->private; | |
320 | ||
321 | bio_free(bio, cc->bs); | |
322 | } | |
323 | ||
1da177e4 LT |
324 | /* |
325 | * Generate a new unfragmented bio with the given size | |
326 | * This should never violate the device limitations | |
327 | * May return a smaller bio when running out of pages | |
328 | */ | |
329 | static struct bio * | |
330 | crypt_alloc_buffer(struct crypt_config *cc, unsigned int size, | |
331 | struct bio *base_bio, unsigned int *bio_vec_idx) | |
332 | { | |
8b004457 | 333 | struct bio *clone; |
1da177e4 | 334 | unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
b4e3ca1a | 335 | gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM; |
1da177e4 LT |
336 | unsigned int i; |
337 | ||
6a24c718 MB |
338 | if (base_bio) { |
339 | clone = bio_alloc_bioset(GFP_NOIO, base_bio->bi_max_vecs, cc->bs); | |
340 | __bio_clone(clone, base_bio); | |
341 | } else | |
342 | clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs); | |
343 | ||
8b004457 | 344 | if (!clone) |
1da177e4 | 345 | return NULL; |
1da177e4 | 346 | |
6a24c718 MB |
347 | clone->bi_destructor = dm_crypt_bio_destructor; |
348 | ||
1da177e4 | 349 | /* if the last bio was not complete, continue where that one ended */ |
8b004457 MB |
350 | clone->bi_idx = *bio_vec_idx; |
351 | clone->bi_vcnt = *bio_vec_idx; | |
352 | clone->bi_size = 0; | |
353 | clone->bi_flags &= ~(1 << BIO_SEG_VALID); | |
1da177e4 | 354 | |
8b004457 MB |
355 | /* clone->bi_idx pages have already been allocated */ |
356 | size -= clone->bi_idx * PAGE_SIZE; | |
1da177e4 | 357 | |
8b004457 MB |
358 | for (i = clone->bi_idx; i < nr_iovecs; i++) { |
359 | struct bio_vec *bv = bio_iovec_idx(clone, i); | |
1da177e4 LT |
360 | |
361 | bv->bv_page = mempool_alloc(cc->page_pool, gfp_mask); | |
362 | if (!bv->bv_page) | |
363 | break; | |
364 | ||
365 | /* | |
366 | * if additional pages cannot be allocated without waiting, | |
367 | * return a partially allocated bio, the caller will then try | |
368 | * to allocate additional bios while submitting this partial bio | |
369 | */ | |
8b004457 | 370 | if ((i - clone->bi_idx) == (MIN_BIO_PAGES - 1)) |
1da177e4 LT |
371 | gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT; |
372 | ||
373 | bv->bv_offset = 0; | |
374 | if (size > PAGE_SIZE) | |
375 | bv->bv_len = PAGE_SIZE; | |
376 | else | |
377 | bv->bv_len = size; | |
378 | ||
8b004457 MB |
379 | clone->bi_size += bv->bv_len; |
380 | clone->bi_vcnt++; | |
1da177e4 LT |
381 | size -= bv->bv_len; |
382 | } | |
383 | ||
8b004457 MB |
384 | if (!clone->bi_size) { |
385 | bio_put(clone); | |
1da177e4 LT |
386 | return NULL; |
387 | } | |
388 | ||
389 | /* | |
390 | * Remember the last bio_vec allocated to be able | |
391 | * to correctly continue after the splitting. | |
392 | */ | |
8b004457 | 393 | *bio_vec_idx = clone->bi_vcnt; |
1da177e4 | 394 | |
8b004457 | 395 | return clone; |
1da177e4 LT |
396 | } |
397 | ||
398 | static void crypt_free_buffer_pages(struct crypt_config *cc, | |
8b004457 | 399 | struct bio *clone, unsigned int bytes) |
1da177e4 LT |
400 | { |
401 | unsigned int i, start, end; | |
402 | struct bio_vec *bv; | |
403 | ||
404 | /* | |
405 | * This is ugly, but Jens Axboe thinks that using bi_idx in the | |
406 | * endio function is too dangerous at the moment, so I calculate the | |
407 | * correct position using bi_vcnt and bi_size. | |
408 | * The bv_offset and bv_len fields might already be modified but we | |
409 | * know that we always allocated whole pages. | |
410 | * A fix to the bi_idx issue in the kernel is in the works, so | |
411 | * we will hopefully be able to revert to the cleaner solution soon. | |
412 | */ | |
8b004457 MB |
413 | i = clone->bi_vcnt - 1; |
414 | bv = bio_iovec_idx(clone, i); | |
415 | end = (i << PAGE_SHIFT) + (bv->bv_offset + bv->bv_len) - clone->bi_size; | |
1da177e4 LT |
416 | start = end - bytes; |
417 | ||
418 | start >>= PAGE_SHIFT; | |
8b004457 MB |
419 | if (!clone->bi_size) |
420 | end = clone->bi_vcnt; | |
1da177e4 LT |
421 | else |
422 | end >>= PAGE_SHIFT; | |
423 | ||
8b004457 MB |
424 | for (i = start; i < end; i++) { |
425 | bv = bio_iovec_idx(clone, i); | |
1da177e4 LT |
426 | BUG_ON(!bv->bv_page); |
427 | mempool_free(bv->bv_page, cc->page_pool); | |
428 | bv->bv_page = NULL; | |
429 | } | |
430 | } | |
431 | ||
432 | /* | |
433 | * One of the bios was finished. Check for completion of | |
434 | * the whole request and correctly clean up the buffer. | |
435 | */ | |
436 | static void dec_pending(struct crypt_io *io, int error) | |
437 | { | |
438 | struct crypt_config *cc = (struct crypt_config *) io->target->private; | |
439 | ||
440 | if (error < 0) | |
441 | io->error = error; | |
442 | ||
443 | if (!atomic_dec_and_test(&io->pending)) | |
444 | return; | |
445 | ||
446 | if (io->first_clone) | |
447 | bio_put(io->first_clone); | |
448 | ||
8b004457 | 449 | bio_endio(io->base_bio, io->base_bio->bi_size, io->error); |
1da177e4 LT |
450 | |
451 | mempool_free(io, cc->io_pool); | |
452 | } | |
453 | ||
454 | /* | |
455 | * kcryptd: | |
456 | * | |
457 | * Needed because it would be very unwise to do decryption in an | |
23541d2d | 458 | * interrupt context. |
1da177e4 LT |
459 | */ |
460 | static struct workqueue_struct *_kcryptd_workqueue; | |
c4028958 | 461 | static void kcryptd_do_work(struct work_struct *work); |
1da177e4 | 462 | |
8b004457 | 463 | static void kcryptd_queue_io(struct crypt_io *io) |
1da177e4 | 464 | { |
c4028958 | 465 | INIT_WORK(&io->work, kcryptd_do_work); |
8b004457 MB |
466 | queue_work(_kcryptd_workqueue, &io->work); |
467 | } | |
468 | ||
469 | static int crypt_endio(struct bio *clone, unsigned int done, int error) | |
470 | { | |
471 | struct crypt_io *io = clone->bi_private; | |
472 | struct crypt_config *cc = io->target->private; | |
473 | unsigned read_io = bio_data_dir(clone) == READ; | |
474 | ||
475 | /* | |
476 | * free the processed pages, even if | |
477 | * it's only a partially completed write | |
478 | */ | |
479 | if (!read_io) | |
480 | crypt_free_buffer_pages(cc, clone, done); | |
481 | ||
23541d2d | 482 | /* keep going - not finished yet */ |
8b004457 MB |
483 | if (unlikely(clone->bi_size)) |
484 | return 1; | |
485 | ||
8b004457 MB |
486 | if (!read_io) |
487 | goto out; | |
488 | ||
489 | if (unlikely(!bio_flagged(clone, BIO_UPTODATE))) { | |
490 | error = -EIO; | |
491 | goto out; | |
492 | } | |
493 | ||
494 | bio_put(clone); | |
23541d2d | 495 | io->post_process = 1; |
8b004457 MB |
496 | kcryptd_queue_io(io); |
497 | return 0; | |
498 | ||
499 | out: | |
500 | bio_put(clone); | |
501 | dec_pending(io, error); | |
502 | return error; | |
503 | } | |
504 | ||
505 | static void clone_init(struct crypt_io *io, struct bio *clone) | |
506 | { | |
507 | struct crypt_config *cc = io->target->private; | |
508 | ||
509 | clone->bi_private = io; | |
510 | clone->bi_end_io = crypt_endio; | |
511 | clone->bi_bdev = cc->dev->bdev; | |
512 | clone->bi_rw = io->base_bio->bi_rw; | |
513 | } | |
514 | ||
23541d2d | 515 | static void process_read(struct crypt_io *io) |
8b004457 MB |
516 | { |
517 | struct crypt_config *cc = io->target->private; | |
518 | struct bio *base_bio = io->base_bio; | |
519 | struct bio *clone; | |
93e605c2 MB |
520 | sector_t sector = base_bio->bi_sector - io->target->begin; |
521 | ||
522 | atomic_inc(&io->pending); | |
8b004457 MB |
523 | |
524 | /* | |
525 | * The block layer might modify the bvec array, so always | |
526 | * copy the required bvecs because we need the original | |
527 | * one in order to decrypt the whole bio data *afterwards*. | |
528 | */ | |
6a24c718 | 529 | clone = bio_alloc_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs); |
93e605c2 MB |
530 | if (unlikely(!clone)) { |
531 | dec_pending(io, -ENOMEM); | |
23541d2d | 532 | return; |
93e605c2 | 533 | } |
8b004457 MB |
534 | |
535 | clone_init(io, clone); | |
6a24c718 | 536 | clone->bi_destructor = dm_crypt_bio_destructor; |
8b004457 MB |
537 | clone->bi_idx = 0; |
538 | clone->bi_vcnt = bio_segments(base_bio); | |
539 | clone->bi_size = base_bio->bi_size; | |
93e605c2 | 540 | clone->bi_sector = cc->start + sector; |
8b004457 MB |
541 | memcpy(clone->bi_io_vec, bio_iovec(base_bio), |
542 | sizeof(struct bio_vec) * clone->bi_vcnt); | |
8b004457 | 543 | |
93e605c2 | 544 | generic_make_request(clone); |
8b004457 MB |
545 | } |
546 | ||
23541d2d | 547 | static void process_write(struct crypt_io *io) |
8b004457 MB |
548 | { |
549 | struct crypt_config *cc = io->target->private; | |
550 | struct bio *base_bio = io->base_bio; | |
551 | struct bio *clone; | |
93e605c2 MB |
552 | struct convert_context ctx; |
553 | unsigned remaining = base_bio->bi_size; | |
554 | sector_t sector = base_bio->bi_sector - io->target->begin; | |
555 | unsigned bvec_idx = 0; | |
8b004457 | 556 | |
93e605c2 | 557 | atomic_inc(&io->pending); |
8b004457 | 558 | |
93e605c2 | 559 | crypt_convert_init(cc, &ctx, NULL, base_bio, sector, 1); |
8b004457 | 560 | |
93e605c2 MB |
561 | /* |
562 | * The allocated buffers can be smaller than the whole bio, | |
563 | * so repeat the whole process until all the data can be handled. | |
564 | */ | |
565 | while (remaining) { | |
566 | clone = crypt_alloc_buffer(cc, base_bio->bi_size, | |
567 | io->first_clone, &bvec_idx); | |
23541d2d MB |
568 | if (unlikely(!clone)) { |
569 | dec_pending(io, -ENOMEM); | |
570 | return; | |
571 | } | |
93e605c2 MB |
572 | |
573 | ctx.bio_out = clone; | |
574 | ||
575 | if (unlikely(crypt_convert(cc, &ctx) < 0)) { | |
576 | crypt_free_buffer_pages(cc, clone, clone->bi_size); | |
577 | bio_put(clone); | |
23541d2d MB |
578 | dec_pending(io, -EIO); |
579 | return; | |
93e605c2 MB |
580 | } |
581 | ||
582 | clone_init(io, clone); | |
583 | clone->bi_sector = cc->start + sector; | |
584 | ||
585 | if (!io->first_clone) { | |
586 | /* | |
587 | * hold a reference to the first clone, because it | |
588 | * holds the bio_vec array and that can't be freed | |
589 | * before all other clones are released | |
590 | */ | |
591 | bio_get(clone); | |
592 | io->first_clone = clone; | |
593 | } | |
594 | ||
93e605c2 MB |
595 | remaining -= clone->bi_size; |
596 | sector += bio_sectors(clone); | |
597 | ||
23541d2d MB |
598 | /* prevent bio_put of first_clone */ |
599 | if (remaining) | |
600 | atomic_inc(&io->pending); | |
601 | ||
93e605c2 MB |
602 | generic_make_request(clone); |
603 | ||
604 | /* out of memory -> run queues */ | |
605 | if (remaining) | |
3fcfab16 | 606 | congestion_wait(bio_data_dir(clone), HZ/100); |
93e605c2 | 607 | } |
8b004457 MB |
608 | } |
609 | ||
610 | static void process_read_endio(struct crypt_io *io) | |
611 | { | |
612 | struct crypt_config *cc = io->target->private; | |
1da177e4 | 613 | struct convert_context ctx; |
1da177e4 | 614 | |
8b004457 MB |
615 | crypt_convert_init(cc, &ctx, io->base_bio, io->base_bio, |
616 | io->base_bio->bi_sector - io->target->begin, 0); | |
1da177e4 | 617 | |
8b004457 | 618 | dec_pending(io, crypt_convert(cc, &ctx)); |
1da177e4 LT |
619 | } |
620 | ||
c4028958 | 621 | static void kcryptd_do_work(struct work_struct *work) |
1da177e4 | 622 | { |
c4028958 | 623 | struct crypt_io *io = container_of(work, struct crypt_io, work); |
8b004457 | 624 | |
23541d2d MB |
625 | if (io->post_process) |
626 | process_read_endio(io); | |
627 | else if (bio_data_dir(io->base_bio) == READ) | |
628 | process_read(io); | |
629 | else | |
630 | process_write(io); | |
1da177e4 LT |
631 | } |
632 | ||
633 | /* | |
634 | * Decode key from its hex representation | |
635 | */ | |
636 | static int crypt_decode_key(u8 *key, char *hex, unsigned int size) | |
637 | { | |
638 | char buffer[3]; | |
639 | char *endp; | |
640 | unsigned int i; | |
641 | ||
642 | buffer[2] = '\0'; | |
643 | ||
8b004457 | 644 | for (i = 0; i < size; i++) { |
1da177e4 LT |
645 | buffer[0] = *hex++; |
646 | buffer[1] = *hex++; | |
647 | ||
648 | key[i] = (u8)simple_strtoul(buffer, &endp, 16); | |
649 | ||
650 | if (endp != &buffer[2]) | |
651 | return -EINVAL; | |
652 | } | |
653 | ||
654 | if (*hex != '\0') | |
655 | return -EINVAL; | |
656 | ||
657 | return 0; | |
658 | } | |
659 | ||
660 | /* | |
661 | * Encode key into its hex representation | |
662 | */ | |
663 | static void crypt_encode_key(char *hex, u8 *key, unsigned int size) | |
664 | { | |
665 | unsigned int i; | |
666 | ||
8b004457 | 667 | for (i = 0; i < size; i++) { |
1da177e4 LT |
668 | sprintf(hex, "%02x", *key); |
669 | hex += 2; | |
670 | key++; | |
671 | } | |
672 | } | |
673 | ||
e48d4bbf MB |
674 | static int crypt_set_key(struct crypt_config *cc, char *key) |
675 | { | |
676 | unsigned key_size = strlen(key) >> 1; | |
677 | ||
678 | if (cc->key_size && cc->key_size != key_size) | |
679 | return -EINVAL; | |
680 | ||
681 | cc->key_size = key_size; /* initial settings */ | |
682 | ||
683 | if ((!key_size && strcmp(key, "-")) || | |
684 | (key_size && crypt_decode_key(cc->key, key, key_size) < 0)) | |
685 | return -EINVAL; | |
686 | ||
687 | set_bit(DM_CRYPT_KEY_VALID, &cc->flags); | |
688 | ||
689 | return 0; | |
690 | } | |
691 | ||
692 | static int crypt_wipe_key(struct crypt_config *cc) | |
693 | { | |
694 | clear_bit(DM_CRYPT_KEY_VALID, &cc->flags); | |
695 | memset(&cc->key, 0, cc->key_size * sizeof(u8)); | |
696 | return 0; | |
697 | } | |
698 | ||
1da177e4 LT |
699 | /* |
700 | * Construct an encryption mapping: | |
701 | * <cipher> <key> <iv_offset> <dev_path> <start> | |
702 | */ | |
703 | static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
704 | { | |
705 | struct crypt_config *cc; | |
d1806f6a | 706 | struct crypto_blkcipher *tfm; |
1da177e4 LT |
707 | char *tmp; |
708 | char *cipher; | |
709 | char *chainmode; | |
710 | char *ivmode; | |
711 | char *ivopts; | |
1da177e4 | 712 | unsigned int key_size; |
4ee218cd | 713 | unsigned long long tmpll; |
1da177e4 LT |
714 | |
715 | if (argc != 5) { | |
72d94861 | 716 | ti->error = "Not enough arguments"; |
1da177e4 LT |
717 | return -EINVAL; |
718 | } | |
719 | ||
720 | tmp = argv[0]; | |
721 | cipher = strsep(&tmp, "-"); | |
722 | chainmode = strsep(&tmp, "-"); | |
723 | ivopts = strsep(&tmp, "-"); | |
724 | ivmode = strsep(&ivopts, ":"); | |
725 | ||
726 | if (tmp) | |
72d94861 | 727 | DMWARN("Unexpected additional cipher options"); |
1da177e4 LT |
728 | |
729 | key_size = strlen(argv[1]) >> 1; | |
730 | ||
e48d4bbf | 731 | cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL); |
1da177e4 LT |
732 | if (cc == NULL) { |
733 | ti->error = | |
72d94861 | 734 | "Cannot allocate transparent encryption context"; |
1da177e4 LT |
735 | return -ENOMEM; |
736 | } | |
737 | ||
e48d4bbf | 738 | if (crypt_set_key(cc, argv[1])) { |
72d94861 | 739 | ti->error = "Error decoding key"; |
1da177e4 LT |
740 | goto bad1; |
741 | } | |
742 | ||
743 | /* Compatiblity mode for old dm-crypt cipher strings */ | |
744 | if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) { | |
745 | chainmode = "cbc"; | |
746 | ivmode = "plain"; | |
747 | } | |
748 | ||
d1806f6a HX |
749 | if (strcmp(chainmode, "ecb") && !ivmode) { |
750 | ti->error = "This chaining mode requires an IV mechanism"; | |
1da177e4 LT |
751 | goto bad1; |
752 | } | |
753 | ||
d1806f6a HX |
754 | if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)", chainmode, |
755 | cipher) >= CRYPTO_MAX_ALG_NAME) { | |
756 | ti->error = "Chain mode + cipher name is too long"; | |
1da177e4 LT |
757 | goto bad1; |
758 | } | |
759 | ||
d1806f6a HX |
760 | tfm = crypto_alloc_blkcipher(cc->cipher, 0, CRYPTO_ALG_ASYNC); |
761 | if (IS_ERR(tfm)) { | |
72d94861 | 762 | ti->error = "Error allocating crypto tfm"; |
1da177e4 LT |
763 | goto bad1; |
764 | } | |
1da177e4 | 765 | |
d1806f6a HX |
766 | strcpy(cc->cipher, cipher); |
767 | strcpy(cc->chainmode, chainmode); | |
1da177e4 LT |
768 | cc->tfm = tfm; |
769 | ||
770 | /* | |
771 | * Choose ivmode. Valid modes: "plain", "essiv:<esshash>". | |
772 | * See comments at iv code | |
773 | */ | |
774 | ||
775 | if (ivmode == NULL) | |
776 | cc->iv_gen_ops = NULL; | |
777 | else if (strcmp(ivmode, "plain") == 0) | |
778 | cc->iv_gen_ops = &crypt_iv_plain_ops; | |
779 | else if (strcmp(ivmode, "essiv") == 0) | |
780 | cc->iv_gen_ops = &crypt_iv_essiv_ops; | |
781 | else { | |
72d94861 | 782 | ti->error = "Invalid IV mode"; |
1da177e4 LT |
783 | goto bad2; |
784 | } | |
785 | ||
786 | if (cc->iv_gen_ops && cc->iv_gen_ops->ctr && | |
787 | cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0) | |
788 | goto bad2; | |
789 | ||
d1806f6a HX |
790 | cc->iv_size = crypto_blkcipher_ivsize(tfm); |
791 | if (cc->iv_size) | |
1da177e4 | 792 | /* at least a 64 bit sector number should fit in our buffer */ |
d1806f6a | 793 | cc->iv_size = max(cc->iv_size, |
1da177e4 LT |
794 | (unsigned int)(sizeof(u64) / sizeof(u8))); |
795 | else { | |
1da177e4 | 796 | if (cc->iv_gen_ops) { |
72d94861 | 797 | DMWARN("Selected cipher does not support IVs"); |
1da177e4 LT |
798 | if (cc->iv_gen_ops->dtr) |
799 | cc->iv_gen_ops->dtr(cc); | |
800 | cc->iv_gen_ops = NULL; | |
801 | } | |
802 | } | |
803 | ||
93d2341c | 804 | cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool); |
1da177e4 | 805 | if (!cc->io_pool) { |
72d94861 | 806 | ti->error = "Cannot allocate crypt io mempool"; |
1da177e4 LT |
807 | goto bad3; |
808 | } | |
809 | ||
a19b27ce | 810 | cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0); |
1da177e4 | 811 | if (!cc->page_pool) { |
72d94861 | 812 | ti->error = "Cannot allocate page mempool"; |
1da177e4 LT |
813 | goto bad4; |
814 | } | |
815 | ||
6a24c718 MB |
816 | cc->bs = bioset_create(MIN_IOS, MIN_IOS, 4); |
817 | if (!cc->bs) { | |
818 | ti->error = "Cannot allocate crypt bioset"; | |
819 | goto bad_bs; | |
820 | } | |
821 | ||
d1806f6a | 822 | if (crypto_blkcipher_setkey(tfm, cc->key, key_size) < 0) { |
72d94861 | 823 | ti->error = "Error setting key"; |
1da177e4 LT |
824 | goto bad5; |
825 | } | |
826 | ||
4ee218cd | 827 | if (sscanf(argv[2], "%llu", &tmpll) != 1) { |
72d94861 | 828 | ti->error = "Invalid iv_offset sector"; |
1da177e4 LT |
829 | goto bad5; |
830 | } | |
4ee218cd | 831 | cc->iv_offset = tmpll; |
1da177e4 | 832 | |
4ee218cd | 833 | if (sscanf(argv[4], "%llu", &tmpll) != 1) { |
72d94861 | 834 | ti->error = "Invalid device sector"; |
1da177e4 LT |
835 | goto bad5; |
836 | } | |
4ee218cd | 837 | cc->start = tmpll; |
1da177e4 LT |
838 | |
839 | if (dm_get_device(ti, argv[3], cc->start, ti->len, | |
840 | dm_table_get_mode(ti->table), &cc->dev)) { | |
72d94861 | 841 | ti->error = "Device lookup failed"; |
1da177e4 LT |
842 | goto bad5; |
843 | } | |
844 | ||
845 | if (ivmode && cc->iv_gen_ops) { | |
846 | if (ivopts) | |
847 | *(ivopts - 1) = ':'; | |
848 | cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL); | |
849 | if (!cc->iv_mode) { | |
72d94861 | 850 | ti->error = "Error kmallocing iv_mode string"; |
1da177e4 LT |
851 | goto bad5; |
852 | } | |
853 | strcpy(cc->iv_mode, ivmode); | |
854 | } else | |
855 | cc->iv_mode = NULL; | |
856 | ||
857 | ti->private = cc; | |
858 | return 0; | |
859 | ||
860 | bad5: | |
6a24c718 MB |
861 | bioset_free(cc->bs); |
862 | bad_bs: | |
1da177e4 LT |
863 | mempool_destroy(cc->page_pool); |
864 | bad4: | |
865 | mempool_destroy(cc->io_pool); | |
866 | bad3: | |
867 | if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) | |
868 | cc->iv_gen_ops->dtr(cc); | |
869 | bad2: | |
d1806f6a | 870 | crypto_free_blkcipher(tfm); |
1da177e4 | 871 | bad1: |
9d3520a3 SR |
872 | /* Must zero key material before freeing */ |
873 | memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8)); | |
1da177e4 LT |
874 | kfree(cc); |
875 | return -EINVAL; | |
876 | } | |
877 | ||
878 | static void crypt_dtr(struct dm_target *ti) | |
879 | { | |
880 | struct crypt_config *cc = (struct crypt_config *) ti->private; | |
881 | ||
6a24c718 | 882 | bioset_free(cc->bs); |
1da177e4 LT |
883 | mempool_destroy(cc->page_pool); |
884 | mempool_destroy(cc->io_pool); | |
885 | ||
990a8baf | 886 | kfree(cc->iv_mode); |
1da177e4 LT |
887 | if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) |
888 | cc->iv_gen_ops->dtr(cc); | |
d1806f6a | 889 | crypto_free_blkcipher(cc->tfm); |
1da177e4 | 890 | dm_put_device(ti, cc->dev); |
9d3520a3 SR |
891 | |
892 | /* Must zero key material before freeing */ | |
893 | memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8)); | |
1da177e4 LT |
894 | kfree(cc); |
895 | } | |
896 | ||
1da177e4 LT |
897 | static int crypt_map(struct dm_target *ti, struct bio *bio, |
898 | union map_info *map_context) | |
899 | { | |
8b004457 | 900 | struct crypt_config *cc = ti->private; |
e48d4bbf | 901 | struct crypt_io *io; |
1da177e4 | 902 | |
e48d4bbf | 903 | io = mempool_alloc(cc->io_pool, GFP_NOIO); |
1da177e4 | 904 | io->target = ti; |
8b004457 | 905 | io->base_bio = bio; |
1da177e4 | 906 | io->first_clone = NULL; |
23541d2d | 907 | io->error = io->post_process = 0; |
93e605c2 | 908 | atomic_set(&io->pending, 0); |
23541d2d | 909 | kcryptd_queue_io(io); |
1da177e4 | 910 | |
23541d2d | 911 | return 0; |
1da177e4 LT |
912 | } |
913 | ||
914 | static int crypt_status(struct dm_target *ti, status_type_t type, | |
915 | char *result, unsigned int maxlen) | |
916 | { | |
917 | struct crypt_config *cc = (struct crypt_config *) ti->private; | |
1da177e4 LT |
918 | unsigned int sz = 0; |
919 | ||
920 | switch (type) { | |
921 | case STATUSTYPE_INFO: | |
922 | result[0] = '\0'; | |
923 | break; | |
924 | ||
925 | case STATUSTYPE_TABLE: | |
1da177e4 | 926 | if (cc->iv_mode) |
37af6560 CS |
927 | DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode, |
928 | cc->iv_mode); | |
1da177e4 | 929 | else |
37af6560 | 930 | DMEMIT("%s-%s ", cc->cipher, cc->chainmode); |
1da177e4 LT |
931 | |
932 | if (cc->key_size > 0) { | |
933 | if ((maxlen - sz) < ((cc->key_size << 1) + 1)) | |
934 | return -ENOMEM; | |
935 | ||
936 | crypt_encode_key(result + sz, cc->key, cc->key_size); | |
937 | sz += cc->key_size << 1; | |
938 | } else { | |
939 | if (sz >= maxlen) | |
940 | return -ENOMEM; | |
941 | result[sz++] = '-'; | |
942 | } | |
943 | ||
4ee218cd AM |
944 | DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset, |
945 | cc->dev->name, (unsigned long long)cc->start); | |
1da177e4 LT |
946 | break; |
947 | } | |
948 | return 0; | |
949 | } | |
950 | ||
e48d4bbf MB |
951 | static void crypt_postsuspend(struct dm_target *ti) |
952 | { | |
953 | struct crypt_config *cc = ti->private; | |
954 | ||
955 | set_bit(DM_CRYPT_SUSPENDED, &cc->flags); | |
956 | } | |
957 | ||
958 | static int crypt_preresume(struct dm_target *ti) | |
959 | { | |
960 | struct crypt_config *cc = ti->private; | |
961 | ||
962 | if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) { | |
963 | DMERR("aborting resume - crypt key is not set."); | |
964 | return -EAGAIN; | |
965 | } | |
966 | ||
967 | return 0; | |
968 | } | |
969 | ||
970 | static void crypt_resume(struct dm_target *ti) | |
971 | { | |
972 | struct crypt_config *cc = ti->private; | |
973 | ||
974 | clear_bit(DM_CRYPT_SUSPENDED, &cc->flags); | |
975 | } | |
976 | ||
977 | /* Message interface | |
978 | * key set <key> | |
979 | * key wipe | |
980 | */ | |
981 | static int crypt_message(struct dm_target *ti, unsigned argc, char **argv) | |
982 | { | |
983 | struct crypt_config *cc = ti->private; | |
984 | ||
985 | if (argc < 2) | |
986 | goto error; | |
987 | ||
988 | if (!strnicmp(argv[0], MESG_STR("key"))) { | |
989 | if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) { | |
990 | DMWARN("not suspended during key manipulation."); | |
991 | return -EINVAL; | |
992 | } | |
993 | if (argc == 3 && !strnicmp(argv[1], MESG_STR("set"))) | |
994 | return crypt_set_key(cc, argv[2]); | |
995 | if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe"))) | |
996 | return crypt_wipe_key(cc); | |
997 | } | |
998 | ||
999 | error: | |
1000 | DMWARN("unrecognised message received."); | |
1001 | return -EINVAL; | |
1002 | } | |
1003 | ||
1da177e4 LT |
1004 | static struct target_type crypt_target = { |
1005 | .name = "crypt", | |
23541d2d | 1006 | .version= {1, 3, 0}, |
1da177e4 LT |
1007 | .module = THIS_MODULE, |
1008 | .ctr = crypt_ctr, | |
1009 | .dtr = crypt_dtr, | |
1010 | .map = crypt_map, | |
1011 | .status = crypt_status, | |
e48d4bbf MB |
1012 | .postsuspend = crypt_postsuspend, |
1013 | .preresume = crypt_preresume, | |
1014 | .resume = crypt_resume, | |
1015 | .message = crypt_message, | |
1da177e4 LT |
1016 | }; |
1017 | ||
1018 | static int __init dm_crypt_init(void) | |
1019 | { | |
1020 | int r; | |
1021 | ||
1022 | _crypt_io_pool = kmem_cache_create("dm-crypt_io", | |
1023 | sizeof(struct crypt_io), | |
1024 | 0, 0, NULL, NULL); | |
1025 | if (!_crypt_io_pool) | |
1026 | return -ENOMEM; | |
1027 | ||
1028 | _kcryptd_workqueue = create_workqueue("kcryptd"); | |
1029 | if (!_kcryptd_workqueue) { | |
1030 | r = -ENOMEM; | |
72d94861 | 1031 | DMERR("couldn't create kcryptd"); |
1da177e4 LT |
1032 | goto bad1; |
1033 | } | |
1034 | ||
1035 | r = dm_register_target(&crypt_target); | |
1036 | if (r < 0) { | |
72d94861 | 1037 | DMERR("register failed %d", r); |
1da177e4 LT |
1038 | goto bad2; |
1039 | } | |
1040 | ||
1041 | return 0; | |
1042 | ||
1043 | bad2: | |
1044 | destroy_workqueue(_kcryptd_workqueue); | |
1045 | bad1: | |
1046 | kmem_cache_destroy(_crypt_io_pool); | |
1047 | return r; | |
1048 | } | |
1049 | ||
1050 | static void __exit dm_crypt_exit(void) | |
1051 | { | |
1052 | int r = dm_unregister_target(&crypt_target); | |
1053 | ||
1054 | if (r < 0) | |
72d94861 | 1055 | DMERR("unregister failed %d", r); |
1da177e4 LT |
1056 | |
1057 | destroy_workqueue(_kcryptd_workqueue); | |
1058 | kmem_cache_destroy(_crypt_io_pool); | |
1059 | } | |
1060 | ||
1061 | module_init(dm_crypt_init); | |
1062 | module_exit(dm_crypt_exit); | |
1063 | ||
1064 | MODULE_AUTHOR("Christophe Saout <christophe@saout.de>"); | |
1065 | MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption"); | |
1066 | MODULE_LICENSE("GPL"); |