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b30ab0e0 MH |
1 | /* |
2 | * linux/fs/ext4/crypto.c | |
3 | * | |
4 | * Copyright (C) 2015, Google, Inc. | |
5 | * | |
6 | * This contains encryption functions for ext4 | |
7 | * | |
8 | * Written by Michael Halcrow, 2014. | |
9 | * | |
10 | * Filename encryption additions | |
11 | * Uday Savagaonkar, 2014 | |
12 | * Encryption policy handling additions | |
13 | * Ildar Muslukhov, 2014 | |
14 | * | |
15 | * This has not yet undergone a rigorous security audit. | |
16 | * | |
17 | * The usage of AES-XTS should conform to recommendations in NIST | |
18 | * Special Publication 800-38E and IEEE P1619/D16. | |
19 | */ | |
20 | ||
21 | #include <crypto/hash.h> | |
22 | #include <crypto/sha.h> | |
23 | #include <keys/user-type.h> | |
24 | #include <keys/encrypted-type.h> | |
25 | #include <linux/crypto.h> | |
26 | #include <linux/ecryptfs.h> | |
27 | #include <linux/gfp.h> | |
28 | #include <linux/kernel.h> | |
29 | #include <linux/key.h> | |
30 | #include <linux/list.h> | |
31 | #include <linux/mempool.h> | |
32 | #include <linux/module.h> | |
33 | #include <linux/mutex.h> | |
34 | #include <linux/random.h> | |
35 | #include <linux/scatterlist.h> | |
36 | #include <linux/spinlock_types.h> | |
37 | ||
38 | #include "ext4_extents.h" | |
39 | #include "xattr.h" | |
40 | ||
41 | /* Encryption added and removed here! (L: */ | |
42 | ||
43 | static unsigned int num_prealloc_crypto_pages = 32; | |
44 | static unsigned int num_prealloc_crypto_ctxs = 128; | |
45 | ||
46 | module_param(num_prealloc_crypto_pages, uint, 0444); | |
47 | MODULE_PARM_DESC(num_prealloc_crypto_pages, | |
48 | "Number of crypto pages to preallocate"); | |
49 | module_param(num_prealloc_crypto_ctxs, uint, 0444); | |
50 | MODULE_PARM_DESC(num_prealloc_crypto_ctxs, | |
51 | "Number of crypto contexts to preallocate"); | |
52 | ||
53 | static mempool_t *ext4_bounce_page_pool; | |
54 | ||
55 | static LIST_HEAD(ext4_free_crypto_ctxs); | |
56 | static DEFINE_SPINLOCK(ext4_crypto_ctx_lock); | |
57 | ||
58 | /** | |
59 | * ext4_release_crypto_ctx() - Releases an encryption context | |
60 | * @ctx: The encryption context to release. | |
61 | * | |
62 | * If the encryption context was allocated from the pre-allocated pool, returns | |
63 | * it to that pool. Else, frees it. | |
64 | * | |
65 | * If there's a bounce page in the context, this frees that. | |
66 | */ | |
67 | void ext4_release_crypto_ctx(struct ext4_crypto_ctx *ctx) | |
68 | { | |
69 | unsigned long flags; | |
70 | ||
71 | if (ctx->bounce_page) { | |
72 | if (ctx->flags & EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL) | |
73 | __free_page(ctx->bounce_page); | |
74 | else | |
75 | mempool_free(ctx->bounce_page, ext4_bounce_page_pool); | |
76 | ctx->bounce_page = NULL; | |
77 | } | |
78 | ctx->control_page = NULL; | |
79 | if (ctx->flags & EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL) { | |
80 | if (ctx->tfm) | |
81 | crypto_free_tfm(ctx->tfm); | |
82 | kfree(ctx); | |
83 | } else { | |
84 | spin_lock_irqsave(&ext4_crypto_ctx_lock, flags); | |
85 | list_add(&ctx->free_list, &ext4_free_crypto_ctxs); | |
86 | spin_unlock_irqrestore(&ext4_crypto_ctx_lock, flags); | |
87 | } | |
88 | } | |
89 | ||
90 | /** | |
91 | * ext4_alloc_and_init_crypto_ctx() - Allocates and inits an encryption context | |
92 | * @mask: The allocation mask. | |
93 | * | |
94 | * Return: An allocated and initialized encryption context on success. An error | |
95 | * value or NULL otherwise. | |
96 | */ | |
97 | static struct ext4_crypto_ctx *ext4_alloc_and_init_crypto_ctx(gfp_t mask) | |
98 | { | |
99 | struct ext4_crypto_ctx *ctx = kzalloc(sizeof(struct ext4_crypto_ctx), | |
100 | mask); | |
101 | ||
102 | if (!ctx) | |
103 | return ERR_PTR(-ENOMEM); | |
104 | return ctx; | |
105 | } | |
106 | ||
107 | /** | |
108 | * ext4_get_crypto_ctx() - Gets an encryption context | |
109 | * @inode: The inode for which we are doing the crypto | |
110 | * | |
111 | * Allocates and initializes an encryption context. | |
112 | * | |
113 | * Return: An allocated and initialized encryption context on success; error | |
114 | * value or NULL otherwise. | |
115 | */ | |
116 | struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode) | |
117 | { | |
118 | struct ext4_crypto_ctx *ctx = NULL; | |
119 | int res = 0; | |
120 | unsigned long flags; | |
e2881b1b | 121 | struct ext4_crypt_info *ci = &EXT4_I(inode)->i_crypt_info; |
b30ab0e0 MH |
122 | |
123 | if (!ext4_read_workqueue) | |
124 | ext4_init_crypto(); | |
125 | ||
126 | /* | |
127 | * We first try getting the ctx from a free list because in | |
128 | * the common case the ctx will have an allocated and | |
129 | * initialized crypto tfm, so it's probably a worthwhile | |
130 | * optimization. For the bounce page, we first try getting it | |
131 | * from the kernel allocator because that's just about as fast | |
132 | * as getting it from a list and because a cache of free pages | |
133 | * should generally be a "last resort" option for a filesystem | |
134 | * to be able to do its job. | |
135 | */ | |
136 | spin_lock_irqsave(&ext4_crypto_ctx_lock, flags); | |
137 | ctx = list_first_entry_or_null(&ext4_free_crypto_ctxs, | |
138 | struct ext4_crypto_ctx, free_list); | |
139 | if (ctx) | |
140 | list_del(&ctx->free_list); | |
141 | spin_unlock_irqrestore(&ext4_crypto_ctx_lock, flags); | |
142 | if (!ctx) { | |
143 | ctx = ext4_alloc_and_init_crypto_ctx(GFP_NOFS); | |
144 | if (IS_ERR(ctx)) { | |
145 | res = PTR_ERR(ctx); | |
146 | goto out; | |
147 | } | |
148 | ctx->flags |= EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL; | |
149 | } else { | |
150 | ctx->flags &= ~EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL; | |
151 | } | |
152 | ||
153 | /* Allocate a new Crypto API context if we don't already have | |
154 | * one or if it isn't the right mode. */ | |
e2881b1b TT |
155 | BUG_ON(ci->ci_mode == EXT4_ENCRYPTION_MODE_INVALID); |
156 | if (ctx->tfm && (ctx->mode != ci->ci_mode)) { | |
b30ab0e0 MH |
157 | crypto_free_tfm(ctx->tfm); |
158 | ctx->tfm = NULL; | |
159 | ctx->mode = EXT4_ENCRYPTION_MODE_INVALID; | |
160 | } | |
161 | if (!ctx->tfm) { | |
e2881b1b | 162 | switch (ci->ci_mode) { |
b30ab0e0 MH |
163 | case EXT4_ENCRYPTION_MODE_AES_256_XTS: |
164 | ctx->tfm = crypto_ablkcipher_tfm( | |
165 | crypto_alloc_ablkcipher("xts(aes)", 0, 0)); | |
166 | break; | |
167 | case EXT4_ENCRYPTION_MODE_AES_256_GCM: | |
168 | /* TODO(mhalcrow): AEAD w/ gcm(aes); | |
169 | * crypto_aead_setauthsize() */ | |
170 | ctx->tfm = ERR_PTR(-ENOTSUPP); | |
171 | break; | |
172 | default: | |
173 | BUG(); | |
174 | } | |
175 | if (IS_ERR_OR_NULL(ctx->tfm)) { | |
176 | res = PTR_ERR(ctx->tfm); | |
177 | ctx->tfm = NULL; | |
178 | goto out; | |
179 | } | |
e2881b1b | 180 | ctx->mode = ci->ci_mode; |
b30ab0e0 | 181 | } |
e2881b1b | 182 | BUG_ON(ci->ci_size != ext4_encryption_key_size(ci->ci_mode)); |
b30ab0e0 MH |
183 | |
184 | /* There shouldn't be a bounce page attached to the crypto | |
185 | * context at this point. */ | |
186 | BUG_ON(ctx->bounce_page); | |
187 | ||
188 | out: | |
189 | if (res) { | |
190 | if (!IS_ERR_OR_NULL(ctx)) | |
191 | ext4_release_crypto_ctx(ctx); | |
192 | ctx = ERR_PTR(res); | |
193 | } | |
194 | return ctx; | |
195 | } | |
196 | ||
197 | struct workqueue_struct *ext4_read_workqueue; | |
198 | static DEFINE_MUTEX(crypto_init); | |
199 | ||
200 | /** | |
201 | * ext4_exit_crypto() - Shutdown the ext4 encryption system | |
202 | */ | |
203 | void ext4_exit_crypto(void) | |
204 | { | |
205 | struct ext4_crypto_ctx *pos, *n; | |
206 | ||
207 | list_for_each_entry_safe(pos, n, &ext4_free_crypto_ctxs, free_list) { | |
208 | if (pos->bounce_page) { | |
209 | if (pos->flags & | |
210 | EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL) { | |
211 | __free_page(pos->bounce_page); | |
212 | } else { | |
213 | mempool_free(pos->bounce_page, | |
214 | ext4_bounce_page_pool); | |
215 | } | |
216 | } | |
217 | if (pos->tfm) | |
218 | crypto_free_tfm(pos->tfm); | |
219 | kfree(pos); | |
220 | } | |
221 | INIT_LIST_HEAD(&ext4_free_crypto_ctxs); | |
222 | if (ext4_bounce_page_pool) | |
223 | mempool_destroy(ext4_bounce_page_pool); | |
224 | ext4_bounce_page_pool = NULL; | |
225 | if (ext4_read_workqueue) | |
226 | destroy_workqueue(ext4_read_workqueue); | |
227 | ext4_read_workqueue = NULL; | |
228 | } | |
229 | ||
230 | /** | |
231 | * ext4_init_crypto() - Set up for ext4 encryption. | |
232 | * | |
233 | * We only call this when we start accessing encrypted files, since it | |
234 | * results in memory getting allocated that wouldn't otherwise be used. | |
235 | * | |
236 | * Return: Zero on success, non-zero otherwise. | |
237 | */ | |
238 | int ext4_init_crypto(void) | |
239 | { | |
240 | int i, res; | |
241 | ||
242 | mutex_lock(&crypto_init); | |
243 | if (ext4_read_workqueue) | |
244 | goto already_initialized; | |
245 | ext4_read_workqueue = alloc_workqueue("ext4_crypto", WQ_HIGHPRI, 0); | |
246 | if (!ext4_read_workqueue) { | |
247 | res = -ENOMEM; | |
248 | goto fail; | |
249 | } | |
250 | ||
251 | for (i = 0; i < num_prealloc_crypto_ctxs; i++) { | |
252 | struct ext4_crypto_ctx *ctx; | |
253 | ||
254 | ctx = ext4_alloc_and_init_crypto_ctx(GFP_KERNEL); | |
255 | if (IS_ERR(ctx)) { | |
256 | res = PTR_ERR(ctx); | |
257 | goto fail; | |
258 | } | |
259 | list_add(&ctx->free_list, &ext4_free_crypto_ctxs); | |
260 | } | |
261 | ||
262 | ext4_bounce_page_pool = | |
263 | mempool_create_page_pool(num_prealloc_crypto_pages, 0); | |
264 | if (!ext4_bounce_page_pool) { | |
265 | res = -ENOMEM; | |
266 | goto fail; | |
267 | } | |
268 | already_initialized: | |
269 | mutex_unlock(&crypto_init); | |
270 | return 0; | |
271 | fail: | |
272 | ext4_exit_crypto(); | |
273 | mutex_unlock(&crypto_init); | |
274 | return res; | |
275 | } | |
276 | ||
277 | void ext4_restore_control_page(struct page *data_page) | |
278 | { | |
279 | struct ext4_crypto_ctx *ctx = | |
280 | (struct ext4_crypto_ctx *)page_private(data_page); | |
281 | ||
282 | set_page_private(data_page, (unsigned long)NULL); | |
283 | ClearPagePrivate(data_page); | |
284 | unlock_page(data_page); | |
285 | ext4_release_crypto_ctx(ctx); | |
286 | } | |
287 | ||
288 | /** | |
289 | * ext4_crypt_complete() - The completion callback for page encryption | |
290 | * @req: The asynchronous encryption request context | |
291 | * @res: The result of the encryption operation | |
292 | */ | |
293 | static void ext4_crypt_complete(struct crypto_async_request *req, int res) | |
294 | { | |
295 | struct ext4_completion_result *ecr = req->data; | |
296 | ||
297 | if (res == -EINPROGRESS) | |
298 | return; | |
299 | ecr->res = res; | |
300 | complete(&ecr->completion); | |
301 | } | |
302 | ||
303 | typedef enum { | |
304 | EXT4_DECRYPT = 0, | |
305 | EXT4_ENCRYPT, | |
306 | } ext4_direction_t; | |
307 | ||
308 | static int ext4_page_crypto(struct ext4_crypto_ctx *ctx, | |
309 | struct inode *inode, | |
310 | ext4_direction_t rw, | |
311 | pgoff_t index, | |
312 | struct page *src_page, | |
313 | struct page *dest_page) | |
314 | ||
315 | { | |
316 | u8 xts_tweak[EXT4_XTS_TWEAK_SIZE]; | |
317 | struct ablkcipher_request *req = NULL; | |
318 | DECLARE_EXT4_COMPLETION_RESULT(ecr); | |
319 | struct scatterlist dst, src; | |
320 | struct ext4_inode_info *ei = EXT4_I(inode); | |
321 | struct crypto_ablkcipher *atfm = __crypto_ablkcipher_cast(ctx->tfm); | |
322 | int res = 0; | |
323 | ||
324 | BUG_ON(!ctx->tfm); | |
e2881b1b | 325 | BUG_ON(ctx->mode != ei->i_crypt_info.ci_mode); |
b30ab0e0 MH |
326 | |
327 | if (ctx->mode != EXT4_ENCRYPTION_MODE_AES_256_XTS) { | |
328 | printk_ratelimited(KERN_ERR | |
329 | "%s: unsupported crypto algorithm: %d\n", | |
330 | __func__, ctx->mode); | |
331 | return -ENOTSUPP; | |
332 | } | |
333 | ||
334 | crypto_ablkcipher_clear_flags(atfm, ~0); | |
335 | crypto_tfm_set_flags(ctx->tfm, CRYPTO_TFM_REQ_WEAK_KEY); | |
336 | ||
e2881b1b TT |
337 | res = crypto_ablkcipher_setkey(atfm, ei->i_crypt_info.ci_raw, |
338 | ei->i_crypt_info.ci_size); | |
b30ab0e0 MH |
339 | if (res) { |
340 | printk_ratelimited(KERN_ERR | |
341 | "%s: crypto_ablkcipher_setkey() failed\n", | |
342 | __func__); | |
343 | return res; | |
344 | } | |
345 | req = ablkcipher_request_alloc(atfm, GFP_NOFS); | |
346 | if (!req) { | |
347 | printk_ratelimited(KERN_ERR | |
348 | "%s: crypto_request_alloc() failed\n", | |
349 | __func__); | |
350 | return -ENOMEM; | |
351 | } | |
352 | ablkcipher_request_set_callback( | |
353 | req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, | |
354 | ext4_crypt_complete, &ecr); | |
355 | ||
356 | BUILD_BUG_ON(EXT4_XTS_TWEAK_SIZE < sizeof(index)); | |
357 | memcpy(xts_tweak, &index, sizeof(index)); | |
358 | memset(&xts_tweak[sizeof(index)], 0, | |
359 | EXT4_XTS_TWEAK_SIZE - sizeof(index)); | |
360 | ||
361 | sg_init_table(&dst, 1); | |
362 | sg_set_page(&dst, dest_page, PAGE_CACHE_SIZE, 0); | |
363 | sg_init_table(&src, 1); | |
364 | sg_set_page(&src, src_page, PAGE_CACHE_SIZE, 0); | |
365 | ablkcipher_request_set_crypt(req, &src, &dst, PAGE_CACHE_SIZE, | |
366 | xts_tweak); | |
367 | if (rw == EXT4_DECRYPT) | |
368 | res = crypto_ablkcipher_decrypt(req); | |
369 | else | |
370 | res = crypto_ablkcipher_encrypt(req); | |
371 | if (res == -EINPROGRESS || res == -EBUSY) { | |
372 | BUG_ON(req->base.data != &ecr); | |
373 | wait_for_completion(&ecr.completion); | |
374 | res = ecr.res; | |
375 | } | |
376 | ablkcipher_request_free(req); | |
377 | if (res) { | |
378 | printk_ratelimited( | |
379 | KERN_ERR | |
380 | "%s: crypto_ablkcipher_encrypt() returned %d\n", | |
381 | __func__, res); | |
382 | return res; | |
383 | } | |
384 | return 0; | |
385 | } | |
386 | ||
387 | /** | |
388 | * ext4_encrypt() - Encrypts a page | |
389 | * @inode: The inode for which the encryption should take place | |
390 | * @plaintext_page: The page to encrypt. Must be locked. | |
391 | * | |
392 | * Allocates a ciphertext page and encrypts plaintext_page into it using the ctx | |
393 | * encryption context. | |
394 | * | |
395 | * Called on the page write path. The caller must call | |
396 | * ext4_restore_control_page() on the returned ciphertext page to | |
397 | * release the bounce buffer and the encryption context. | |
398 | * | |
399 | * Return: An allocated page with the encrypted content on success. Else, an | |
400 | * error value or NULL. | |
401 | */ | |
402 | struct page *ext4_encrypt(struct inode *inode, | |
403 | struct page *plaintext_page) | |
404 | { | |
405 | struct ext4_crypto_ctx *ctx; | |
406 | struct page *ciphertext_page = NULL; | |
407 | int err; | |
408 | ||
409 | BUG_ON(!PageLocked(plaintext_page)); | |
410 | ||
411 | ctx = ext4_get_crypto_ctx(inode); | |
412 | if (IS_ERR(ctx)) | |
413 | return (struct page *) ctx; | |
414 | ||
415 | /* The encryption operation will require a bounce page. */ | |
416 | ciphertext_page = alloc_page(GFP_NOFS); | |
417 | if (!ciphertext_page) { | |
418 | /* This is a potential bottleneck, but at least we'll have | |
419 | * forward progress. */ | |
420 | ciphertext_page = mempool_alloc(ext4_bounce_page_pool, | |
421 | GFP_NOFS); | |
422 | if (WARN_ON_ONCE(!ciphertext_page)) { | |
423 | ciphertext_page = mempool_alloc(ext4_bounce_page_pool, | |
424 | GFP_NOFS | __GFP_WAIT); | |
425 | } | |
426 | ctx->flags &= ~EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL; | |
427 | } else { | |
428 | ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL; | |
429 | } | |
430 | ctx->bounce_page = ciphertext_page; | |
431 | ctx->control_page = plaintext_page; | |
432 | err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, plaintext_page->index, | |
433 | plaintext_page, ciphertext_page); | |
434 | if (err) { | |
435 | ext4_release_crypto_ctx(ctx); | |
436 | return ERR_PTR(err); | |
437 | } | |
438 | SetPagePrivate(ciphertext_page); | |
439 | set_page_private(ciphertext_page, (unsigned long)ctx); | |
440 | lock_page(ciphertext_page); | |
441 | return ciphertext_page; | |
442 | } | |
443 | ||
444 | /** | |
445 | * ext4_decrypt() - Decrypts a page in-place | |
446 | * @ctx: The encryption context. | |
447 | * @page: The page to decrypt. Must be locked. | |
448 | * | |
449 | * Decrypts page in-place using the ctx encryption context. | |
450 | * | |
451 | * Called from the read completion callback. | |
452 | * | |
453 | * Return: Zero on success, non-zero otherwise. | |
454 | */ | |
455 | int ext4_decrypt(struct ext4_crypto_ctx *ctx, struct page *page) | |
456 | { | |
457 | BUG_ON(!PageLocked(page)); | |
458 | ||
459 | return ext4_page_crypto(ctx, page->mapping->host, | |
460 | EXT4_DECRYPT, page->index, page, page); | |
461 | } | |
462 | ||
463 | /* | |
464 | * Convenience function which takes care of allocating and | |
465 | * deallocating the encryption context | |
466 | */ | |
467 | int ext4_decrypt_one(struct inode *inode, struct page *page) | |
468 | { | |
469 | int ret; | |
470 | ||
471 | struct ext4_crypto_ctx *ctx = ext4_get_crypto_ctx(inode); | |
472 | ||
473 | if (!ctx) | |
474 | return -ENOMEM; | |
475 | ret = ext4_decrypt(ctx, page); | |
476 | ext4_release_crypto_ctx(ctx); | |
477 | return ret; | |
478 | } | |
479 | ||
480 | int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex) | |
481 | { | |
482 | struct ext4_crypto_ctx *ctx; | |
483 | struct page *ciphertext_page = NULL; | |
484 | struct bio *bio; | |
485 | ext4_lblk_t lblk = ex->ee_block; | |
486 | ext4_fsblk_t pblk = ext4_ext_pblock(ex); | |
487 | unsigned int len = ext4_ext_get_actual_len(ex); | |
488 | int err = 0; | |
489 | ||
490 | BUG_ON(inode->i_sb->s_blocksize != PAGE_CACHE_SIZE); | |
491 | ||
492 | ctx = ext4_get_crypto_ctx(inode); | |
493 | if (IS_ERR(ctx)) | |
494 | return PTR_ERR(ctx); | |
495 | ||
496 | ciphertext_page = alloc_page(GFP_NOFS); | |
497 | if (!ciphertext_page) { | |
498 | /* This is a potential bottleneck, but at least we'll have | |
499 | * forward progress. */ | |
500 | ciphertext_page = mempool_alloc(ext4_bounce_page_pool, | |
501 | GFP_NOFS); | |
502 | if (WARN_ON_ONCE(!ciphertext_page)) { | |
503 | ciphertext_page = mempool_alloc(ext4_bounce_page_pool, | |
504 | GFP_NOFS | __GFP_WAIT); | |
505 | } | |
506 | ctx->flags &= ~EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL; | |
507 | } else { | |
508 | ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL; | |
509 | } | |
510 | ctx->bounce_page = ciphertext_page; | |
511 | ||
512 | while (len--) { | |
513 | err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, lblk, | |
514 | ZERO_PAGE(0), ciphertext_page); | |
515 | if (err) | |
516 | goto errout; | |
517 | ||
518 | bio = bio_alloc(GFP_KERNEL, 1); | |
519 | if (!bio) { | |
520 | err = -ENOMEM; | |
521 | goto errout; | |
522 | } | |
523 | bio->bi_bdev = inode->i_sb->s_bdev; | |
524 | bio->bi_iter.bi_sector = pblk; | |
525 | err = bio_add_page(bio, ciphertext_page, | |
526 | inode->i_sb->s_blocksize, 0); | |
527 | if (err) { | |
528 | bio_put(bio); | |
529 | goto errout; | |
530 | } | |
531 | err = submit_bio_wait(WRITE, bio); | |
532 | if (err) | |
533 | goto errout; | |
534 | } | |
535 | err = 0; | |
536 | errout: | |
537 | ext4_release_crypto_ctx(ctx); | |
538 | return err; | |
539 | } | |
540 | ||
541 | bool ext4_valid_contents_enc_mode(uint32_t mode) | |
542 | { | |
543 | return (mode == EXT4_ENCRYPTION_MODE_AES_256_XTS); | |
544 | } | |
545 | ||
546 | /** | |
547 | * ext4_validate_encryption_key_size() - Validate the encryption key size | |
548 | * @mode: The key mode. | |
549 | * @size: The key size to validate. | |
550 | * | |
551 | * Return: The validated key size for @mode. Zero if invalid. | |
552 | */ | |
553 | uint32_t ext4_validate_encryption_key_size(uint32_t mode, uint32_t size) | |
554 | { | |
555 | if (size == ext4_encryption_key_size(mode)) | |
556 | return size; | |
557 | return 0; | |
558 | } |