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-crypto.h> |
14 | #include <linux/blk-crypto-profile.h> |
15 | #include <linux/blkdev.h> |
16 | #include <linux/crypto.h> |
17 | #include <linux/mempool.h> |
18 | #include <linux/module.h> |
19 | #include <linux/random.h> |
20 | #include <linux/scatterlist.h> |
21 | |
22 | #include "blk-cgroup.h" |
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 | |
76 | static struct blk_crypto_fallback_keyslot { |
77 | enum blk_crypto_mode_num crypto_mode; |
78 | struct crypto_skcipher *tfms[BLK_ENCRYPTION_MODE_MAX]; |
79 | } *blk_crypto_keyslots; |
80 | |
81 | static struct blk_crypto_profile *blk_crypto_fallback_profile; |
82 | static struct workqueue_struct *blk_crypto_wq; |
83 | static mempool_t *blk_crypto_bounce_page_pool; |
84 | static struct bio_set crypto_bio_split; |
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 | |
92 | static void blk_crypto_fallback_evict_keyslot(unsigned int slot) |
93 | { |
94 | struct blk_crypto_fallback_keyslot *slotp = &blk_crypto_keyslots[slot]; |
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(tfm: slotp->tfms[crypto_mode], key: blank_key, |
102 | keylen: blk_crypto_modes[crypto_mode].keysize); |
103 | WARN_ON(err); |
104 | slotp->crypto_mode = BLK_ENCRYPTION_MODE_INVALID; |
105 | } |
106 | |
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) |
111 | { |
112 | struct blk_crypto_fallback_keyslot *slotp = &blk_crypto_keyslots[slot]; |
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) |
119 | blk_crypto_fallback_evict_keyslot(slot); |
120 | |
121 | slotp->crypto_mode = crypto_mode; |
122 | err = crypto_skcipher_setkey(tfm: slotp->tfms[crypto_mode], key: key->raw, |
123 | keylen: key->size); |
124 | if (err) { |
125 | blk_crypto_fallback_evict_keyslot(slot); |
126 | return err; |
127 | } |
128 | return 0; |
129 | } |
130 | |
131 | static int blk_crypto_fallback_keyslot_evict(struct blk_crypto_profile *profile, |
132 | const struct blk_crypto_key *key, |
133 | unsigned int slot) |
134 | { |
135 | blk_crypto_fallback_evict_keyslot(slot); |
136 | return 0; |
137 | } |
138 | |
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, |
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(element: enc_bio->bi_io_vec[i].bv_page, |
151 | pool: blk_crypto_bounce_page_pool); |
152 | |
153 | src_bio->bi_status = enc_bio->bi_status; |
154 | |
155 | bio_uninit(enc_bio); |
156 | kfree(objp: enc_bio); |
157 | bio_endio(src_bio); |
158 | } |
159 | |
160 | static struct bio *blk_crypto_fallback_clone_bio(struct bio *bio_src) |
161 | { |
162 | unsigned int nr_segs = bio_segments(bio: bio_src); |
163 | struct bvec_iter iter; |
164 | struct bio_vec bv; |
165 | struct bio *bio; |
166 | |
167 | bio = bio_kmalloc(nr_vecs: nr_segs, GFP_NOIO); |
168 | if (!bio) |
169 | return NULL; |
170 | bio_init(bio, bdev: bio_src->bi_bdev, table: bio->bi_inline_vecs, max_vecs: nr_segs, |
171 | opf: bio_src->bi_opf); |
172 | if (bio_flagged(bio: bio_src, bit: BIO_REMAPPED)) |
173 | bio_set_flag(bio, bit: BIO_REMAPPED); |
174 | bio->bi_ioprio = bio_src->bi_ioprio; |
175 | bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector; |
176 | bio->bi_iter.bi_size = bio_src->bi_iter.bi_size; |
177 | |
178 | bio_for_each_segment(bv, bio_src, iter) |
179 | bio->bi_io_vec[bio->bi_vcnt++] = bv; |
180 | |
181 | bio_clone_blkg_association(dst: bio, src: bio_src); |
182 | |
183 | return bio; |
184 | } |
185 | |
186 | static bool |
187 | blk_crypto_fallback_alloc_cipher_req(struct blk_crypto_keyslot *slot, |
188 | struct skcipher_request **ciph_req_ret, |
189 | struct crypto_wait *wait) |
190 | { |
191 | struct skcipher_request *ciph_req; |
192 | const struct blk_crypto_fallback_keyslot *slotp; |
193 | int keyslot_idx = blk_crypto_keyslot_index(slot); |
194 | |
195 | slotp = &blk_crypto_keyslots[keyslot_idx]; |
196 | ciph_req = skcipher_request_alloc(tfm: slotp->tfms[slotp->crypto_mode], |
197 | GFP_NOIO); |
198 | if (!ciph_req) |
199 | return false; |
200 | |
201 | skcipher_request_set_callback(req: ciph_req, |
202 | CRYPTO_TFM_REQ_MAY_BACKLOG | |
203 | CRYPTO_TFM_REQ_MAY_SLEEP, |
204 | compl: crypto_req_done, data: wait); |
205 | *ciph_req_ret = ciph_req; |
206 | |
207 | return true; |
208 | } |
209 | |
210 | static bool blk_crypto_fallback_split_bio_if_needed(struct bio **bio_ptr) |
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; |
220 | if (++i == BIO_MAX_VECS) |
221 | break; |
222 | } |
223 | if (num_sectors < bio_sectors(bio)) { |
224 | struct bio *split_bio; |
225 | |
226 | split_bio = bio_split(bio, sectors: num_sectors, GFP_NOIO, |
227 | bs: &crypto_bio_split); |
228 | if (!split_bio) { |
229 | bio->bi_status = BLK_STS_RESOURCE; |
230 | return false; |
231 | } |
232 | bio_chain(split_bio, bio); |
233 | submit_bio_noacct(bio); |
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; |
265 | struct blk_crypto_keyslot *slot; |
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 */ |
277 | if (!blk_crypto_fallback_split_bio_if_needed(bio_ptr)) |
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 */ |
285 | enc_bio = blk_crypto_fallback_clone_bio(bio_src: src_bio); |
286 | if (!enc_bio) { |
287 | src_bio->bi_status = BLK_STS_RESOURCE; |
288 | return false; |
289 | } |
290 | |
291 | /* |
292 | * Get a blk-crypto-fallback keyslot that contains a crypto_skcipher for |
293 | * this bio's algorithm and key. |
294 | */ |
295 | blk_st = blk_crypto_get_keyslot(profile: blk_crypto_fallback_profile, |
296 | key: bc->bc_key, slot_ptr: &slot); |
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 */ |
303 | if (!blk_crypto_fallback_alloc_cipher_req(slot, ciph_req_ret: &ciph_req, wait: &wait)) { |
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(req: ciph_req, src: &src, dst: &dst, cryptlen: data_unit_size, |
313 | iv: 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(pool: 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(sg: &src, page: plaintext_page, len: data_unit_size, |
330 | offset: enc_bvec->bv_offset); |
331 | sg_set_page(sg: &dst, page: ciphertext_page, len: data_unit_size, |
332 | offset: 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(dun: curr_dun, iv: &iv); |
337 | if (crypto_wait_req(err: crypto_skcipher_encrypt(req: ciph_req), |
338 | wait: &wait)) { |
339 | i++; |
340 | src_bio->bi_status = BLK_STS_IOERR; |
341 | goto out_free_bounce_pages; |
342 | } |
343 | bio_crypt_dun_increment(dun: curr_dun, inc: 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(element: enc_bio->bi_io_vec[--i].bv_page, |
360 | pool: blk_crypto_bounce_page_pool); |
361 | out_free_ciph_req: |
362 | skcipher_request_free(req: ciph_req); |
363 | out_release_keyslot: |
364 | blk_crypto_put_keyslot(slot); |
365 | out_put_enc_bio: |
366 | if (enc_bio) |
367 | bio_uninit(enc_bio); |
368 | kfree(objp: enc_bio); |
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; |
382 | struct blk_crypto_keyslot *slot; |
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 | /* |
395 | * Get a blk-crypto-fallback keyslot that contains a crypto_skcipher for |
396 | * this bio's algorithm and key. |
397 | */ |
398 | blk_st = blk_crypto_get_keyslot(profile: blk_crypto_fallback_profile, |
399 | key: bc->bc_key, slot_ptr: &slot); |
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 */ |
406 | if (!blk_crypto_fallback_alloc_cipher_req(slot, ciph_req_ret: &ciph_req, wait: &wait)) { |
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(req: ciph_req, src: &sg, dst: &sg, cryptlen: data_unit_size, |
414 | iv: 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: &sg, page, len: data_unit_size, offset: 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(dun: curr_dun, iv: &iv); |
425 | if (crypto_wait_req(err: crypto_skcipher_decrypt(req: ciph_req), |
426 | wait: &wait)) { |
427 | bio->bi_status = BLK_STS_IOERR; |
428 | goto out; |
429 | } |
430 | bio_crypt_dun_increment(dun: curr_dun, inc: 1); |
431 | sg.offset += data_unit_size; |
432 | } |
433 | } |
434 | |
435 | out: |
436 | skcipher_request_free(req: ciph_req); |
437 | blk_crypto_put_keyslot(slot); |
438 | out_no_keyslot: |
439 | mempool_free(element: f_ctx, pool: 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(element: f_ctx, pool: 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(wq: blk_crypto_wq, work: &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 |
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. |
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 | |
502 | if (!__blk_crypto_cfg_supported(profile: blk_crypto_fallback_profile, |
503 | cfg: &bc->bc_key->crypto_cfg)) { |
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(pool: 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 | { |
529 | return __blk_crypto_evict_key(profile: blk_crypto_fallback_profile, key); |
530 | } |
531 | |
532 | static bool blk_crypto_fallback_inited; |
533 | static int blk_crypto_fallback_init(void) |
534 | { |
535 | int i; |
536 | int err; |
537 | |
538 | if (blk_crypto_fallback_inited) |
539 | return 0; |
540 | |
541 | get_random_bytes(buf: blank_key, BLK_CRYPTO_MAX_KEY_SIZE); |
542 | |
543 | err = bioset_init(&crypto_bio_split, 64, 0, flags: 0); |
544 | if (err) |
545 | goto out; |
546 | |
547 | /* Dynamic allocation is needed because of lockdep_register_key(). */ |
548 | blk_crypto_fallback_profile = |
549 | kzalloc(size: sizeof(*blk_crypto_fallback_profile), GFP_KERNEL); |
550 | if (!blk_crypto_fallback_profile) { |
551 | err = -ENOMEM; |
552 | goto fail_free_bioset; |
553 | } |
554 | |
555 | err = blk_crypto_profile_init(profile: blk_crypto_fallback_profile, |
556 | num_slots: blk_crypto_num_keyslots); |
557 | if (err) |
558 | goto fail_free_profile; |
559 | err = -ENOMEM; |
560 | |
561 | blk_crypto_fallback_profile->ll_ops = blk_crypto_fallback_ll_ops; |
562 | blk_crypto_fallback_profile->max_dun_bytes_supported = BLK_CRYPTO_MAX_IV_SIZE; |
563 | |
564 | /* All blk-crypto modes have a crypto API fallback. */ |
565 | for (i = 0; i < BLK_ENCRYPTION_MODE_MAX; i++) |
566 | blk_crypto_fallback_profile->modes_supported[i] = 0xFFFFFFFF; |
567 | blk_crypto_fallback_profile->modes_supported[BLK_ENCRYPTION_MODE_INVALID] = 0; |
568 | |
569 | blk_crypto_wq = alloc_workqueue(fmt: "blk_crypto_wq" , |
570 | flags: WQ_UNBOUND | WQ_HIGHPRI | |
571 | WQ_MEM_RECLAIM, max_active: num_online_cpus()); |
572 | if (!blk_crypto_wq) |
573 | goto fail_destroy_profile; |
574 | |
575 | blk_crypto_keyslots = kcalloc(n: blk_crypto_num_keyslots, |
576 | size: sizeof(blk_crypto_keyslots[0]), |
577 | GFP_KERNEL); |
578 | if (!blk_crypto_keyslots) |
579 | goto fail_free_wq; |
580 | |
581 | blk_crypto_bounce_page_pool = |
582 | mempool_create_page_pool(min_nr: num_prealloc_bounce_pg, order: 0); |
583 | if (!blk_crypto_bounce_page_pool) |
584 | goto fail_free_keyslots; |
585 | |
586 | bio_fallback_crypt_ctx_cache = KMEM_CACHE(bio_fallback_crypt_ctx, 0); |
587 | if (!bio_fallback_crypt_ctx_cache) |
588 | goto fail_free_bounce_page_pool; |
589 | |
590 | bio_fallback_crypt_ctx_pool = |
591 | mempool_create_slab_pool(min_nr: num_prealloc_fallback_crypt_ctxs, |
592 | kc: bio_fallback_crypt_ctx_cache); |
593 | if (!bio_fallback_crypt_ctx_pool) |
594 | goto fail_free_crypt_ctx_cache; |
595 | |
596 | blk_crypto_fallback_inited = true; |
597 | |
598 | return 0; |
599 | fail_free_crypt_ctx_cache: |
600 | kmem_cache_destroy(s: bio_fallback_crypt_ctx_cache); |
601 | fail_free_bounce_page_pool: |
602 | mempool_destroy(pool: blk_crypto_bounce_page_pool); |
603 | fail_free_keyslots: |
604 | kfree(objp: blk_crypto_keyslots); |
605 | fail_free_wq: |
606 | destroy_workqueue(wq: blk_crypto_wq); |
607 | fail_destroy_profile: |
608 | blk_crypto_profile_destroy(profile: blk_crypto_fallback_profile); |
609 | fail_free_profile: |
610 | kfree(objp: blk_crypto_fallback_profile); |
611 | fail_free_bioset: |
612 | bioset_exit(&crypto_bio_split); |
613 | out: |
614 | return err; |
615 | } |
616 | |
617 | /* |
618 | * Prepare blk-crypto-fallback for the specified crypto mode. |
619 | * Returns -ENOPKG if the needed crypto API support is missing. |
620 | */ |
621 | int blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num) |
622 | { |
623 | const char *cipher_str = blk_crypto_modes[mode_num].cipher_str; |
624 | struct blk_crypto_fallback_keyslot *slotp; |
625 | unsigned int i; |
626 | int err = 0; |
627 | |
628 | /* |
629 | * Fast path |
630 | * Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num] |
631 | * for each i are visible before we try to access them. |
632 | */ |
633 | if (likely(smp_load_acquire(&tfms_inited[mode_num]))) |
634 | return 0; |
635 | |
636 | mutex_lock(&tfms_init_lock); |
637 | if (tfms_inited[mode_num]) |
638 | goto out; |
639 | |
640 | err = blk_crypto_fallback_init(); |
641 | if (err) |
642 | goto out; |
643 | |
644 | for (i = 0; i < blk_crypto_num_keyslots; i++) { |
645 | slotp = &blk_crypto_keyslots[i]; |
646 | slotp->tfms[mode_num] = crypto_alloc_skcipher(alg_name: cipher_str, type: 0, mask: 0); |
647 | if (IS_ERR(ptr: slotp->tfms[mode_num])) { |
648 | err = PTR_ERR(ptr: slotp->tfms[mode_num]); |
649 | if (err == -ENOENT) { |
650 | pr_warn_once("Missing crypto API support for \"%s\"\n" , |
651 | cipher_str); |
652 | err = -ENOPKG; |
653 | } |
654 | slotp->tfms[mode_num] = NULL; |
655 | goto out_free_tfms; |
656 | } |
657 | |
658 | crypto_skcipher_set_flags(tfm: slotp->tfms[mode_num], |
659 | CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); |
660 | } |
661 | |
662 | /* |
663 | * Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num] |
664 | * for each i are visible before we set tfms_inited[mode_num]. |
665 | */ |
666 | smp_store_release(&tfms_inited[mode_num], true); |
667 | goto out; |
668 | |
669 | out_free_tfms: |
670 | for (i = 0; i < blk_crypto_num_keyslots; i++) { |
671 | slotp = &blk_crypto_keyslots[i]; |
672 | crypto_free_skcipher(tfm: slotp->tfms[mode_num]); |
673 | slotp->tfms[mode_num] = NULL; |
674 | } |
675 | out: |
676 | mutex_unlock(lock: &tfms_init_lock); |
677 | return err; |
678 | } |
679 | |