Michael Halcrow | b30ab0e | 2015-04-12 00:43:56 -0400 | [diff] [blame] | 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; |
| 121 | struct ext4_encryption_key *key = &EXT4_I(inode)->i_encryption_key; |
| 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. */ |
| 155 | BUG_ON(key->mode == EXT4_ENCRYPTION_MODE_INVALID); |
| 156 | if (ctx->tfm && (ctx->mode != key->mode)) { |
| 157 | crypto_free_tfm(ctx->tfm); |
| 158 | ctx->tfm = NULL; |
| 159 | ctx->mode = EXT4_ENCRYPTION_MODE_INVALID; |
| 160 | } |
| 161 | if (!ctx->tfm) { |
| 162 | switch (key->mode) { |
| 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 | } |
| 180 | ctx->mode = key->mode; |
| 181 | } |
| 182 | BUG_ON(key->size != ext4_encryption_key_size(key->mode)); |
| 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); |
| 325 | BUG_ON(ctx->mode != ei->i_encryption_key.mode); |
| 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 | |
| 337 | res = crypto_ablkcipher_setkey(atfm, ei->i_encryption_key.raw, |
| 338 | ei->i_encryption_key.size); |
| 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 | } |