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488f6682 ST |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Copyright 2019 Google LLC | |
4 | */ | |
5 | ||
6 | /* | |
7 | * Refer to Documentation/block/inline-encryption.rst for detailed explanation. | |
8 | */ | |
9 | ||
10 | #define pr_fmt(fmt) "blk-crypto-fallback: " fmt | |
11 | ||
12 | #include <crypto/skcipher.h> | |
13 | #include <linux/blk-cgroup.h> | |
14 | #include <linux/blk-crypto.h> | |
1e8d44bd | 15 | #include <linux/blk-crypto-profile.h> |
488f6682 ST |
16 | #include <linux/blkdev.h> |
17 | #include <linux/crypto.h> | |
488f6682 ST |
18 | #include <linux/mempool.h> |
19 | #include <linux/module.h> | |
20 | #include <linux/random.h> | |
24b83deb | 21 | #include <linux/scatterlist.h> |
488f6682 ST |
22 | |
23 | #include "blk-crypto-internal.h" | |
24 | ||
25 | static unsigned int num_prealloc_bounce_pg = 32; | |
26 | module_param(num_prealloc_bounce_pg, uint, 0); | |
27 | MODULE_PARM_DESC(num_prealloc_bounce_pg, | |
28 | "Number of preallocated bounce pages for the blk-crypto crypto API fallback"); | |
29 | ||
30 | static unsigned int blk_crypto_num_keyslots = 100; | |
31 | module_param_named(num_keyslots, blk_crypto_num_keyslots, uint, 0); | |
32 | MODULE_PARM_DESC(num_keyslots, | |
33 | "Number of keyslots for the blk-crypto crypto API fallback"); | |
34 | ||
35 | static unsigned int num_prealloc_fallback_crypt_ctxs = 128; | |
36 | module_param(num_prealloc_fallback_crypt_ctxs, uint, 0); | |
37 | MODULE_PARM_DESC(num_prealloc_crypt_fallback_ctxs, | |
38 | "Number of preallocated bio fallback crypto contexts for blk-crypto to use during crypto API fallback"); | |
39 | ||
40 | struct bio_fallback_crypt_ctx { | |
41 | struct bio_crypt_ctx crypt_ctx; | |
42 | /* | |
43 | * Copy of the bvec_iter when this bio was submitted. | |
44 | * We only want to en/decrypt the part of the bio as described by the | |
45 | * bvec_iter upon submission because bio might be split before being | |
46 | * resubmitted | |
47 | */ | |
48 | struct bvec_iter crypt_iter; | |
49 | union { | |
50 | struct { | |
51 | struct work_struct work; | |
52 | struct bio *bio; | |
53 | }; | |
54 | struct { | |
55 | void *bi_private_orig; | |
56 | bio_end_io_t *bi_end_io_orig; | |
57 | }; | |
58 | }; | |
59 | }; | |
60 | ||
61 | static struct kmem_cache *bio_fallback_crypt_ctx_cache; | |
62 | static mempool_t *bio_fallback_crypt_ctx_pool; | |
63 | ||
64 | /* | |
65 | * Allocating a crypto tfm during I/O can deadlock, so we have to preallocate | |
66 | * all of a mode's tfms when that mode starts being used. Since each mode may | |
67 | * need all the keyslots at some point, each mode needs its own tfm for each | |
68 | * keyslot; thus, a keyslot may contain tfms for multiple modes. However, to | |
69 | * match the behavior of real inline encryption hardware (which only supports a | |
70 | * single encryption context per keyslot), we only allow one tfm per keyslot to | |
71 | * be used at a time - the rest of the unused tfms have their keys cleared. | |
72 | */ | |
73 | static DEFINE_MUTEX(tfms_init_lock); | |
74 | static bool tfms_inited[BLK_ENCRYPTION_MODE_MAX]; | |
75 | ||
eebcafae | 76 | static struct blk_crypto_fallback_keyslot { |
488f6682 ST |
77 | enum blk_crypto_mode_num crypto_mode; |
78 | struct crypto_skcipher *tfms[BLK_ENCRYPTION_MODE_MAX]; | |
79 | } *blk_crypto_keyslots; | |
80 | ||
cb77cb5a | 81 | static struct blk_crypto_profile blk_crypto_fallback_profile; |
488f6682 ST |
82 | static struct workqueue_struct *blk_crypto_wq; |
83 | static mempool_t *blk_crypto_bounce_page_pool; | |
5407334c | 84 | static struct bio_set crypto_bio_split; |
488f6682 ST |
85 | |
86 | /* | |
87 | * This is the key we set when evicting a keyslot. This *should* be the all 0's | |
88 | * key, but AES-XTS rejects that key, so we use some random bytes instead. | |
89 | */ | |
90 | static u8 blank_key[BLK_CRYPTO_MAX_KEY_SIZE]; | |
91 | ||
eebcafae | 92 | static void blk_crypto_fallback_evict_keyslot(unsigned int slot) |
488f6682 | 93 | { |
eebcafae | 94 | struct blk_crypto_fallback_keyslot *slotp = &blk_crypto_keyslots[slot]; |
488f6682 ST |
95 | enum blk_crypto_mode_num crypto_mode = slotp->crypto_mode; |
96 | int err; | |
97 | ||
98 | WARN_ON(slotp->crypto_mode == BLK_ENCRYPTION_MODE_INVALID); | |
99 | ||
100 | /* Clear the key in the skcipher */ | |
101 | err = crypto_skcipher_setkey(slotp->tfms[crypto_mode], blank_key, | |
102 | blk_crypto_modes[crypto_mode].keysize); | |
103 | WARN_ON(err); | |
104 | slotp->crypto_mode = BLK_ENCRYPTION_MODE_INVALID; | |
105 | } | |
106 | ||
cb77cb5a EB |
107 | static int |
108 | blk_crypto_fallback_keyslot_program(struct blk_crypto_profile *profile, | |
109 | const struct blk_crypto_key *key, | |
110 | unsigned int slot) | |
488f6682 | 111 | { |
eebcafae | 112 | struct blk_crypto_fallback_keyslot *slotp = &blk_crypto_keyslots[slot]; |
488f6682 ST |
113 | const enum blk_crypto_mode_num crypto_mode = |
114 | key->crypto_cfg.crypto_mode; | |
115 | int err; | |
116 | ||
117 | if (crypto_mode != slotp->crypto_mode && | |
118 | slotp->crypto_mode != BLK_ENCRYPTION_MODE_INVALID) | |
eebcafae | 119 | blk_crypto_fallback_evict_keyslot(slot); |
488f6682 ST |
120 | |
121 | slotp->crypto_mode = crypto_mode; | |
122 | err = crypto_skcipher_setkey(slotp->tfms[crypto_mode], key->raw, | |
123 | key->size); | |
124 | if (err) { | |
eebcafae | 125 | blk_crypto_fallback_evict_keyslot(slot); |
488f6682 ST |
126 | return err; |
127 | } | |
128 | return 0; | |
129 | } | |
130 | ||
cb77cb5a | 131 | static int blk_crypto_fallback_keyslot_evict(struct blk_crypto_profile *profile, |
eebcafae EB |
132 | const struct blk_crypto_key *key, |
133 | unsigned int slot) | |
488f6682 | 134 | { |
eebcafae | 135 | blk_crypto_fallback_evict_keyslot(slot); |
488f6682 ST |
136 | return 0; |
137 | } | |
138 | ||
cb77cb5a EB |
139 | static const struct blk_crypto_ll_ops blk_crypto_fallback_ll_ops = { |
140 | .keyslot_program = blk_crypto_fallback_keyslot_program, | |
141 | .keyslot_evict = blk_crypto_fallback_keyslot_evict, | |
488f6682 ST |
142 | }; |
143 | ||
144 | static void blk_crypto_fallback_encrypt_endio(struct bio *enc_bio) | |
145 | { | |
146 | struct bio *src_bio = enc_bio->bi_private; | |
147 | int i; | |
148 | ||
149 | for (i = 0; i < enc_bio->bi_vcnt; i++) | |
150 | mempool_free(enc_bio->bi_io_vec[i].bv_page, | |
151 | blk_crypto_bounce_page_pool); | |
152 | ||
153 | src_bio->bi_status = enc_bio->bi_status; | |
154 | ||
155 | bio_put(enc_bio); | |
156 | bio_endio(src_bio); | |
157 | } | |
158 | ||
eebcafae | 159 | static struct bio *blk_crypto_fallback_clone_bio(struct bio *bio_src) |
488f6682 ST |
160 | { |
161 | struct bvec_iter iter; | |
162 | struct bio_vec bv; | |
163 | struct bio *bio; | |
164 | ||
4eb1d689 | 165 | bio = bio_kmalloc(GFP_NOIO, bio_segments(bio_src)); |
488f6682 ST |
166 | if (!bio) |
167 | return NULL; | |
309dca30 | 168 | bio->bi_bdev = bio_src->bi_bdev; |
46bbf653 CH |
169 | if (bio_flagged(bio_src, BIO_REMAPPED)) |
170 | bio_set_flag(bio, BIO_REMAPPED); | |
488f6682 ST |
171 | bio->bi_opf = bio_src->bi_opf; |
172 | bio->bi_ioprio = bio_src->bi_ioprio; | |
173 | bio->bi_write_hint = bio_src->bi_write_hint; | |
174 | bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector; | |
175 | bio->bi_iter.bi_size = bio_src->bi_iter.bi_size; | |
176 | ||
177 | bio_for_each_segment(bv, bio_src, iter) | |
178 | bio->bi_io_vec[bio->bi_vcnt++] = bv; | |
179 | ||
180 | bio_clone_blkg_association(bio, bio_src); | |
181 | blkcg_bio_issue_init(bio); | |
182 | ||
183 | return bio; | |
184 | } | |
185 | ||
eebcafae | 186 | static bool |
cb77cb5a | 187 | blk_crypto_fallback_alloc_cipher_req(struct blk_crypto_keyslot *slot, |
eebcafae EB |
188 | struct skcipher_request **ciph_req_ret, |
189 | struct crypto_wait *wait) | |
488f6682 ST |
190 | { |
191 | struct skcipher_request *ciph_req; | |
eebcafae | 192 | const struct blk_crypto_fallback_keyslot *slotp; |
cb77cb5a | 193 | int keyslot_idx = blk_crypto_keyslot_index(slot); |
488f6682 ST |
194 | |
195 | slotp = &blk_crypto_keyslots[keyslot_idx]; | |
196 | ciph_req = skcipher_request_alloc(slotp->tfms[slotp->crypto_mode], | |
197 | GFP_NOIO); | |
198 | if (!ciph_req) | |
199 | return false; | |
200 | ||
201 | skcipher_request_set_callback(ciph_req, | |
202 | CRYPTO_TFM_REQ_MAY_BACKLOG | | |
203 | CRYPTO_TFM_REQ_MAY_SLEEP, | |
204 | crypto_req_done, wait); | |
205 | *ciph_req_ret = ciph_req; | |
206 | ||
207 | return true; | |
208 | } | |
209 | ||
eebcafae | 210 | static bool blk_crypto_fallback_split_bio_if_needed(struct bio **bio_ptr) |
488f6682 ST |
211 | { |
212 | struct bio *bio = *bio_ptr; | |
213 | unsigned int i = 0; | |
214 | unsigned int num_sectors = 0; | |
215 | struct bio_vec bv; | |
216 | struct bvec_iter iter; | |
217 | ||
218 | bio_for_each_segment(bv, bio, iter) { | |
219 | num_sectors += bv.bv_len >> SECTOR_SHIFT; | |
a8affc03 | 220 | if (++i == BIO_MAX_VECS) |
488f6682 ST |
221 | break; |
222 | } | |
223 | if (num_sectors < bio_sectors(bio)) { | |
224 | struct bio *split_bio; | |
225 | ||
5407334c CH |
226 | split_bio = bio_split(bio, num_sectors, GFP_NOIO, |
227 | &crypto_bio_split); | |
488f6682 ST |
228 | if (!split_bio) { |
229 | bio->bi_status = BLK_STS_RESOURCE; | |
230 | return false; | |
231 | } | |
232 | bio_chain(split_bio, bio); | |
ed00aabd | 233 | submit_bio_noacct(bio); |
488f6682 ST |
234 | *bio_ptr = split_bio; |
235 | } | |
236 | ||
237 | return true; | |
238 | } | |
239 | ||
240 | union blk_crypto_iv { | |
241 | __le64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE]; | |
242 | u8 bytes[BLK_CRYPTO_MAX_IV_SIZE]; | |
243 | }; | |
244 | ||
245 | static void blk_crypto_dun_to_iv(const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE], | |
246 | union blk_crypto_iv *iv) | |
247 | { | |
248 | int i; | |
249 | ||
250 | for (i = 0; i < BLK_CRYPTO_DUN_ARRAY_SIZE; i++) | |
251 | iv->dun[i] = cpu_to_le64(dun[i]); | |
252 | } | |
253 | ||
254 | /* | |
255 | * The crypto API fallback's encryption routine. | |
256 | * Allocate a bounce bio for encryption, encrypt the input bio using crypto API, | |
257 | * and replace *bio_ptr with the bounce bio. May split input bio if it's too | |
258 | * large. Returns true on success. Returns false and sets bio->bi_status on | |
259 | * error. | |
260 | */ | |
261 | static bool blk_crypto_fallback_encrypt_bio(struct bio **bio_ptr) | |
262 | { | |
263 | struct bio *src_bio, *enc_bio; | |
264 | struct bio_crypt_ctx *bc; | |
cb77cb5a | 265 | struct blk_crypto_keyslot *slot; |
488f6682 ST |
266 | int data_unit_size; |
267 | struct skcipher_request *ciph_req = NULL; | |
268 | DECLARE_CRYPTO_WAIT(wait); | |
269 | u64 curr_dun[BLK_CRYPTO_DUN_ARRAY_SIZE]; | |
270 | struct scatterlist src, dst; | |
271 | union blk_crypto_iv iv; | |
272 | unsigned int i, j; | |
273 | bool ret = false; | |
274 | blk_status_t blk_st; | |
275 | ||
276 | /* Split the bio if it's too big for single page bvec */ | |
eebcafae | 277 | if (!blk_crypto_fallback_split_bio_if_needed(bio_ptr)) |
488f6682 ST |
278 | return false; |
279 | ||
280 | src_bio = *bio_ptr; | |
281 | bc = src_bio->bi_crypt_context; | |
282 | data_unit_size = bc->bc_key->crypto_cfg.data_unit_size; | |
283 | ||
284 | /* Allocate bounce bio for encryption */ | |
eebcafae | 285 | enc_bio = blk_crypto_fallback_clone_bio(src_bio); |
488f6682 ST |
286 | if (!enc_bio) { |
287 | src_bio->bi_status = BLK_STS_RESOURCE; | |
288 | return false; | |
289 | } | |
290 | ||
291 | /* | |
cb77cb5a EB |
292 | * Get a blk-crypto-fallback keyslot that contains a crypto_skcipher for |
293 | * this bio's algorithm and key. | |
488f6682 | 294 | */ |
cb77cb5a EB |
295 | blk_st = blk_crypto_get_keyslot(&blk_crypto_fallback_profile, |
296 | bc->bc_key, &slot); | |
488f6682 ST |
297 | if (blk_st != BLK_STS_OK) { |
298 | src_bio->bi_status = blk_st; | |
299 | goto out_put_enc_bio; | |
300 | } | |
301 | ||
302 | /* and then allocate an skcipher_request for it */ | |
eebcafae | 303 | if (!blk_crypto_fallback_alloc_cipher_req(slot, &ciph_req, &wait)) { |
488f6682 ST |
304 | src_bio->bi_status = BLK_STS_RESOURCE; |
305 | goto out_release_keyslot; | |
306 | } | |
307 | ||
308 | memcpy(curr_dun, bc->bc_dun, sizeof(curr_dun)); | |
309 | sg_init_table(&src, 1); | |
310 | sg_init_table(&dst, 1); | |
311 | ||
312 | skcipher_request_set_crypt(ciph_req, &src, &dst, data_unit_size, | |
313 | iv.bytes); | |
314 | ||
315 | /* Encrypt each page in the bounce bio */ | |
316 | for (i = 0; i < enc_bio->bi_vcnt; i++) { | |
317 | struct bio_vec *enc_bvec = &enc_bio->bi_io_vec[i]; | |
318 | struct page *plaintext_page = enc_bvec->bv_page; | |
319 | struct page *ciphertext_page = | |
320 | mempool_alloc(blk_crypto_bounce_page_pool, GFP_NOIO); | |
321 | ||
322 | enc_bvec->bv_page = ciphertext_page; | |
323 | ||
324 | if (!ciphertext_page) { | |
325 | src_bio->bi_status = BLK_STS_RESOURCE; | |
326 | goto out_free_bounce_pages; | |
327 | } | |
328 | ||
329 | sg_set_page(&src, plaintext_page, data_unit_size, | |
330 | enc_bvec->bv_offset); | |
331 | sg_set_page(&dst, ciphertext_page, data_unit_size, | |
332 | enc_bvec->bv_offset); | |
333 | ||
334 | /* Encrypt each data unit in this page */ | |
335 | for (j = 0; j < enc_bvec->bv_len; j += data_unit_size) { | |
336 | blk_crypto_dun_to_iv(curr_dun, &iv); | |
337 | if (crypto_wait_req(crypto_skcipher_encrypt(ciph_req), | |
338 | &wait)) { | |
339 | i++; | |
340 | src_bio->bi_status = BLK_STS_IOERR; | |
341 | goto out_free_bounce_pages; | |
342 | } | |
343 | bio_crypt_dun_increment(curr_dun, 1); | |
344 | src.offset += data_unit_size; | |
345 | dst.offset += data_unit_size; | |
346 | } | |
347 | } | |
348 | ||
349 | enc_bio->bi_private = src_bio; | |
350 | enc_bio->bi_end_io = blk_crypto_fallback_encrypt_endio; | |
351 | *bio_ptr = enc_bio; | |
352 | ret = true; | |
353 | ||
354 | enc_bio = NULL; | |
355 | goto out_free_ciph_req; | |
356 | ||
357 | out_free_bounce_pages: | |
358 | while (i > 0) | |
359 | mempool_free(enc_bio->bi_io_vec[--i].bv_page, | |
360 | blk_crypto_bounce_page_pool); | |
361 | out_free_ciph_req: | |
362 | skcipher_request_free(ciph_req); | |
363 | out_release_keyslot: | |
cb77cb5a | 364 | blk_crypto_put_keyslot(slot); |
488f6682 ST |
365 | out_put_enc_bio: |
366 | if (enc_bio) | |
367 | bio_put(enc_bio); | |
368 | ||
369 | return ret; | |
370 | } | |
371 | ||
372 | /* | |
373 | * The crypto API fallback's main decryption routine. | |
374 | * Decrypts input bio in place, and calls bio_endio on the bio. | |
375 | */ | |
376 | static void blk_crypto_fallback_decrypt_bio(struct work_struct *work) | |
377 | { | |
378 | struct bio_fallback_crypt_ctx *f_ctx = | |
379 | container_of(work, struct bio_fallback_crypt_ctx, work); | |
380 | struct bio *bio = f_ctx->bio; | |
381 | struct bio_crypt_ctx *bc = &f_ctx->crypt_ctx; | |
cb77cb5a | 382 | struct blk_crypto_keyslot *slot; |
488f6682 ST |
383 | struct skcipher_request *ciph_req = NULL; |
384 | DECLARE_CRYPTO_WAIT(wait); | |
385 | u64 curr_dun[BLK_CRYPTO_DUN_ARRAY_SIZE]; | |
386 | union blk_crypto_iv iv; | |
387 | struct scatterlist sg; | |
388 | struct bio_vec bv; | |
389 | struct bvec_iter iter; | |
390 | const int data_unit_size = bc->bc_key->crypto_cfg.data_unit_size; | |
391 | unsigned int i; | |
392 | blk_status_t blk_st; | |
393 | ||
394 | /* | |
cb77cb5a EB |
395 | * Get a blk-crypto-fallback keyslot that contains a crypto_skcipher for |
396 | * this bio's algorithm and key. | |
488f6682 | 397 | */ |
cb77cb5a EB |
398 | blk_st = blk_crypto_get_keyslot(&blk_crypto_fallback_profile, |
399 | bc->bc_key, &slot); | |
488f6682 ST |
400 | if (blk_st != BLK_STS_OK) { |
401 | bio->bi_status = blk_st; | |
402 | goto out_no_keyslot; | |
403 | } | |
404 | ||
405 | /* and then allocate an skcipher_request for it */ | |
eebcafae | 406 | if (!blk_crypto_fallback_alloc_cipher_req(slot, &ciph_req, &wait)) { |
488f6682 ST |
407 | bio->bi_status = BLK_STS_RESOURCE; |
408 | goto out; | |
409 | } | |
410 | ||
411 | memcpy(curr_dun, bc->bc_dun, sizeof(curr_dun)); | |
412 | sg_init_table(&sg, 1); | |
413 | skcipher_request_set_crypt(ciph_req, &sg, &sg, data_unit_size, | |
414 | iv.bytes); | |
415 | ||
416 | /* Decrypt each segment in the bio */ | |
417 | __bio_for_each_segment(bv, bio, iter, f_ctx->crypt_iter) { | |
418 | struct page *page = bv.bv_page; | |
419 | ||
420 | sg_set_page(&sg, page, data_unit_size, bv.bv_offset); | |
421 | ||
422 | /* Decrypt each data unit in the segment */ | |
423 | for (i = 0; i < bv.bv_len; i += data_unit_size) { | |
424 | blk_crypto_dun_to_iv(curr_dun, &iv); | |
425 | if (crypto_wait_req(crypto_skcipher_decrypt(ciph_req), | |
426 | &wait)) { | |
427 | bio->bi_status = BLK_STS_IOERR; | |
428 | goto out; | |
429 | } | |
430 | bio_crypt_dun_increment(curr_dun, 1); | |
431 | sg.offset += data_unit_size; | |
432 | } | |
433 | } | |
434 | ||
435 | out: | |
436 | skcipher_request_free(ciph_req); | |
cb77cb5a | 437 | blk_crypto_put_keyslot(slot); |
488f6682 ST |
438 | out_no_keyslot: |
439 | mempool_free(f_ctx, bio_fallback_crypt_ctx_pool); | |
440 | bio_endio(bio); | |
441 | } | |
442 | ||
443 | /** | |
444 | * blk_crypto_fallback_decrypt_endio - queue bio for fallback decryption | |
445 | * | |
446 | * @bio: the bio to queue | |
447 | * | |
448 | * Restore bi_private and bi_end_io, and queue the bio for decryption into a | |
449 | * workqueue, since this function will be called from an atomic context. | |
450 | */ | |
451 | static void blk_crypto_fallback_decrypt_endio(struct bio *bio) | |
452 | { | |
453 | struct bio_fallback_crypt_ctx *f_ctx = bio->bi_private; | |
454 | ||
455 | bio->bi_private = f_ctx->bi_private_orig; | |
456 | bio->bi_end_io = f_ctx->bi_end_io_orig; | |
457 | ||
458 | /* If there was an IO error, don't queue for decrypt. */ | |
459 | if (bio->bi_status) { | |
460 | mempool_free(f_ctx, bio_fallback_crypt_ctx_pool); | |
461 | bio_endio(bio); | |
462 | return; | |
463 | } | |
464 | ||
465 | INIT_WORK(&f_ctx->work, blk_crypto_fallback_decrypt_bio); | |
466 | f_ctx->bio = bio; | |
467 | queue_work(blk_crypto_wq, &f_ctx->work); | |
468 | } | |
469 | ||
470 | /** | |
471 | * blk_crypto_fallback_bio_prep - Prepare a bio to use fallback en/decryption | |
472 | * | |
473 | * @bio_ptr: pointer to the bio to prepare | |
474 | * | |
475 | * If bio is doing a WRITE operation, this splits the bio into two parts if it's | |
eebcafae EB |
476 | * too big (see blk_crypto_fallback_split_bio_if_needed()). It then allocates a |
477 | * bounce bio for the first part, encrypts it, and updates bio_ptr to point to | |
478 | * the bounce bio. | |
488f6682 ST |
479 | * |
480 | * For a READ operation, we mark the bio for decryption by using bi_private and | |
481 | * bi_end_io. | |
482 | * | |
483 | * In either case, this function will make the bio look like a regular bio (i.e. | |
484 | * as if no encryption context was ever specified) for the purposes of the rest | |
485 | * of the stack except for blk-integrity (blk-integrity and blk-crypto are not | |
486 | * currently supported together). | |
487 | * | |
488 | * Return: true on success. Sets bio->bi_status and returns false on error. | |
489 | */ | |
490 | bool blk_crypto_fallback_bio_prep(struct bio **bio_ptr) | |
491 | { | |
492 | struct bio *bio = *bio_ptr; | |
493 | struct bio_crypt_ctx *bc = bio->bi_crypt_context; | |
494 | struct bio_fallback_crypt_ctx *f_ctx; | |
495 | ||
496 | if (WARN_ON_ONCE(!tfms_inited[bc->bc_key->crypto_cfg.crypto_mode])) { | |
497 | /* User didn't call blk_crypto_start_using_key() first */ | |
498 | bio->bi_status = BLK_STS_IOERR; | |
499 | return false; | |
500 | } | |
501 | ||
cb77cb5a EB |
502 | if (!__blk_crypto_cfg_supported(&blk_crypto_fallback_profile, |
503 | &bc->bc_key->crypto_cfg)) { | |
488f6682 ST |
504 | bio->bi_status = BLK_STS_NOTSUPP; |
505 | return false; | |
506 | } | |
507 | ||
508 | if (bio_data_dir(bio) == WRITE) | |
509 | return blk_crypto_fallback_encrypt_bio(bio_ptr); | |
510 | ||
511 | /* | |
512 | * bio READ case: Set up a f_ctx in the bio's bi_private and set the | |
513 | * bi_end_io appropriately to trigger decryption when the bio is ended. | |
514 | */ | |
515 | f_ctx = mempool_alloc(bio_fallback_crypt_ctx_pool, GFP_NOIO); | |
516 | f_ctx->crypt_ctx = *bc; | |
517 | f_ctx->crypt_iter = bio->bi_iter; | |
518 | f_ctx->bi_private_orig = bio->bi_private; | |
519 | f_ctx->bi_end_io_orig = bio->bi_end_io; | |
520 | bio->bi_private = (void *)f_ctx; | |
521 | bio->bi_end_io = blk_crypto_fallback_decrypt_endio; | |
522 | bio_crypt_free_ctx(bio); | |
523 | ||
524 | return true; | |
525 | } | |
526 | ||
527 | int blk_crypto_fallback_evict_key(const struct blk_crypto_key *key) | |
528 | { | |
cb77cb5a | 529 | return __blk_crypto_evict_key(&blk_crypto_fallback_profile, key); |
488f6682 ST |
530 | } |
531 | ||
532 | static bool blk_crypto_fallback_inited; | |
533 | static int blk_crypto_fallback_init(void) | |
534 | { | |
535 | int i; | |
e7ecc142 | 536 | int err; |
cb77cb5a | 537 | struct blk_crypto_profile *profile = &blk_crypto_fallback_profile; |
488f6682 ST |
538 | |
539 | if (blk_crypto_fallback_inited) | |
540 | return 0; | |
541 | ||
542 | prandom_bytes(blank_key, BLK_CRYPTO_MAX_KEY_SIZE); | |
543 | ||
5407334c | 544 | err = bioset_init(&crypto_bio_split, 64, 0, 0); |
488f6682 ST |
545 | if (err) |
546 | goto out; | |
5407334c | 547 | |
cb77cb5a | 548 | err = blk_crypto_profile_init(profile, blk_crypto_num_keyslots); |
5407334c CH |
549 | if (err) |
550 | goto fail_free_bioset; | |
488f6682 ST |
551 | err = -ENOMEM; |
552 | ||
cb77cb5a EB |
553 | profile->ll_ops = blk_crypto_fallback_ll_ops; |
554 | profile->max_dun_bytes_supported = BLK_CRYPTO_MAX_IV_SIZE; | |
488f6682 ST |
555 | |
556 | /* All blk-crypto modes have a crypto API fallback. */ | |
557 | for (i = 0; i < BLK_ENCRYPTION_MODE_MAX; i++) | |
cb77cb5a EB |
558 | profile->modes_supported[i] = 0xFFFFFFFF; |
559 | profile->modes_supported[BLK_ENCRYPTION_MODE_INVALID] = 0; | |
488f6682 ST |
560 | |
561 | blk_crypto_wq = alloc_workqueue("blk_crypto_wq", | |
562 | WQ_UNBOUND | WQ_HIGHPRI | | |
563 | WQ_MEM_RECLAIM, num_online_cpus()); | |
564 | if (!blk_crypto_wq) | |
cb77cb5a | 565 | goto fail_destroy_profile; |
488f6682 ST |
566 | |
567 | blk_crypto_keyslots = kcalloc(blk_crypto_num_keyslots, | |
568 | sizeof(blk_crypto_keyslots[0]), | |
569 | GFP_KERNEL); | |
570 | if (!blk_crypto_keyslots) | |
571 | goto fail_free_wq; | |
572 | ||
573 | blk_crypto_bounce_page_pool = | |
574 | mempool_create_page_pool(num_prealloc_bounce_pg, 0); | |
575 | if (!blk_crypto_bounce_page_pool) | |
576 | goto fail_free_keyslots; | |
577 | ||
578 | bio_fallback_crypt_ctx_cache = KMEM_CACHE(bio_fallback_crypt_ctx, 0); | |
579 | if (!bio_fallback_crypt_ctx_cache) | |
580 | goto fail_free_bounce_page_pool; | |
581 | ||
582 | bio_fallback_crypt_ctx_pool = | |
583 | mempool_create_slab_pool(num_prealloc_fallback_crypt_ctxs, | |
584 | bio_fallback_crypt_ctx_cache); | |
585 | if (!bio_fallback_crypt_ctx_pool) | |
586 | goto fail_free_crypt_ctx_cache; | |
587 | ||
588 | blk_crypto_fallback_inited = true; | |
589 | ||
590 | return 0; | |
591 | fail_free_crypt_ctx_cache: | |
592 | kmem_cache_destroy(bio_fallback_crypt_ctx_cache); | |
593 | fail_free_bounce_page_pool: | |
594 | mempool_destroy(blk_crypto_bounce_page_pool); | |
595 | fail_free_keyslots: | |
596 | kfree(blk_crypto_keyslots); | |
597 | fail_free_wq: | |
598 | destroy_workqueue(blk_crypto_wq); | |
cb77cb5a EB |
599 | fail_destroy_profile: |
600 | blk_crypto_profile_destroy(profile); | |
5407334c CH |
601 | fail_free_bioset: |
602 | bioset_exit(&crypto_bio_split); | |
488f6682 ST |
603 | out: |
604 | return err; | |
605 | } | |
606 | ||
607 | /* | |
608 | * Prepare blk-crypto-fallback for the specified crypto mode. | |
609 | * Returns -ENOPKG if the needed crypto API support is missing. | |
610 | */ | |
611 | int blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num) | |
612 | { | |
613 | const char *cipher_str = blk_crypto_modes[mode_num].cipher_str; | |
eebcafae | 614 | struct blk_crypto_fallback_keyslot *slotp; |
488f6682 ST |
615 | unsigned int i; |
616 | int err = 0; | |
617 | ||
618 | /* | |
619 | * Fast path | |
620 | * Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num] | |
621 | * for each i are visible before we try to access them. | |
622 | */ | |
623 | if (likely(smp_load_acquire(&tfms_inited[mode_num]))) | |
624 | return 0; | |
625 | ||
626 | mutex_lock(&tfms_init_lock); | |
627 | if (tfms_inited[mode_num]) | |
628 | goto out; | |
629 | ||
630 | err = blk_crypto_fallback_init(); | |
631 | if (err) | |
632 | goto out; | |
633 | ||
634 | for (i = 0; i < blk_crypto_num_keyslots; i++) { | |
635 | slotp = &blk_crypto_keyslots[i]; | |
636 | slotp->tfms[mode_num] = crypto_alloc_skcipher(cipher_str, 0, 0); | |
637 | if (IS_ERR(slotp->tfms[mode_num])) { | |
638 | err = PTR_ERR(slotp->tfms[mode_num]); | |
639 | if (err == -ENOENT) { | |
640 | pr_warn_once("Missing crypto API support for \"%s\"\n", | |
641 | cipher_str); | |
642 | err = -ENOPKG; | |
643 | } | |
644 | slotp->tfms[mode_num] = NULL; | |
645 | goto out_free_tfms; | |
646 | } | |
647 | ||
648 | crypto_skcipher_set_flags(slotp->tfms[mode_num], | |
649 | CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); | |
650 | } | |
651 | ||
652 | /* | |
653 | * Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num] | |
654 | * for each i are visible before we set tfms_inited[mode_num]. | |
655 | */ | |
656 | smp_store_release(&tfms_inited[mode_num], true); | |
657 | goto out; | |
658 | ||
659 | out_free_tfms: | |
660 | for (i = 0; i < blk_crypto_num_keyslots; i++) { | |
661 | slotp = &blk_crypto_keyslots[i]; | |
662 | crypto_free_skcipher(slotp->tfms[mode_num]); | |
663 | slotp->tfms[mode_num] = NULL; | |
664 | } | |
665 | out: | |
666 | mutex_unlock(&tfms_init_lock); | |
667 | return err; | |
668 | } |