1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * fscrypt_private.h 4 * 5 * Copyright (C) 2015, Google, Inc. 6 * 7 * Originally written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar. 8 * Heavily modified since then. 9 */ 10 11 #ifndef _FSCRYPT_PRIVATE_H 12 #define _FSCRYPT_PRIVATE_H 13 14 #include <linux/fscrypt.h> 15 #include <linux/siphash.h> 16 #include <crypto/hash.h> 17 #include <linux/blk-crypto.h> 18 19 #define CONST_STRLEN(str) (sizeof(str) - 1) 20 21 #define FSCRYPT_FILE_NONCE_SIZE 16 22 23 /* 24 * Minimum size of an fscrypt master key. Note: a longer key will be required 25 * if ciphers with a 256-bit security strength are used. This is just the 26 * absolute minimum, which applies when only 128-bit encryption is used. 27 */ 28 #define FSCRYPT_MIN_KEY_SIZE 16 29 30 #define FSCRYPT_CONTEXT_V1 1 31 #define FSCRYPT_CONTEXT_V2 2 32 33 /* Keep this in sync with include/uapi/linux/fscrypt.h */ 34 #define FSCRYPT_MODE_MAX FSCRYPT_MODE_AES_256_HCTR2 35 36 struct fscrypt_context_v1 { 37 u8 version; /* FSCRYPT_CONTEXT_V1 */ 38 u8 contents_encryption_mode; 39 u8 filenames_encryption_mode; 40 u8 flags; 41 u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE]; 42 u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; 43 }; 44 45 struct fscrypt_context_v2 { 46 u8 version; /* FSCRYPT_CONTEXT_V2 */ 47 u8 contents_encryption_mode; 48 u8 filenames_encryption_mode; 49 u8 flags; 50 u8 log2_data_unit_size; 51 u8 __reserved[3]; 52 u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]; 53 u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; 54 }; 55 56 /* 57 * fscrypt_context - the encryption context of an inode 58 * 59 * This is the on-disk equivalent of an fscrypt_policy, stored alongside each 60 * encrypted file usually in a hidden extended attribute. It contains the 61 * fields from the fscrypt_policy, in order to identify the encryption algorithm 62 * and key with which the file is encrypted. It also contains a nonce that was 63 * randomly generated by fscrypt itself; this is used as KDF input or as a tweak 64 * to cause different files to be encrypted differently. 65 */ 66 union fscrypt_context { 67 u8 version; 68 struct fscrypt_context_v1 v1; 69 struct fscrypt_context_v2 v2; 70 }; 71 72 /* 73 * Return the size expected for the given fscrypt_context based on its version 74 * number, or 0 if the context version is unrecognized. 75 */ 76 static inline int fscrypt_context_size(const union fscrypt_context *ctx) 77 { 78 switch (ctx->version) { 79 case FSCRYPT_CONTEXT_V1: 80 BUILD_BUG_ON(sizeof(ctx->v1) != 28); 81 return sizeof(ctx->v1); 82 case FSCRYPT_CONTEXT_V2: 83 BUILD_BUG_ON(sizeof(ctx->v2) != 40); 84 return sizeof(ctx->v2); 85 } 86 return 0; 87 } 88 89 /* Check whether an fscrypt_context has a recognized version number and size */ 90 static inline bool fscrypt_context_is_valid(const union fscrypt_context *ctx, 91 int ctx_size) 92 { 93 return ctx_size >= 1 && ctx_size == fscrypt_context_size(ctx); 94 } 95 96 /* Retrieve the context's nonce, assuming the context was already validated */ 97 static inline const u8 *fscrypt_context_nonce(const union fscrypt_context *ctx) 98 { 99 switch (ctx->version) { 100 case FSCRYPT_CONTEXT_V1: 101 return ctx->v1.nonce; 102 case FSCRYPT_CONTEXT_V2: 103 return ctx->v2.nonce; 104 } 105 WARN_ON_ONCE(1); 106 return NULL; 107 } 108 109 union fscrypt_policy { 110 u8 version; 111 struct fscrypt_policy_v1 v1; 112 struct fscrypt_policy_v2 v2; 113 }; 114 115 /* 116 * Return the size expected for the given fscrypt_policy based on its version 117 * number, or 0 if the policy version is unrecognized. 118 */ 119 static inline int fscrypt_policy_size(const union fscrypt_policy *policy) 120 { 121 switch (policy->version) { 122 case FSCRYPT_POLICY_V1: 123 return sizeof(policy->v1); 124 case FSCRYPT_POLICY_V2: 125 return sizeof(policy->v2); 126 } 127 return 0; 128 } 129 130 /* Return the contents encryption mode of a valid encryption policy */ 131 static inline u8 132 fscrypt_policy_contents_mode(const union fscrypt_policy *policy) 133 { 134 switch (policy->version) { 135 case FSCRYPT_POLICY_V1: 136 return policy->v1.contents_encryption_mode; 137 case FSCRYPT_POLICY_V2: 138 return policy->v2.contents_encryption_mode; 139 } 140 BUG(); 141 } 142 143 /* Return the filenames encryption mode of a valid encryption policy */ 144 static inline u8 145 fscrypt_policy_fnames_mode(const union fscrypt_policy *policy) 146 { 147 switch (policy->version) { 148 case FSCRYPT_POLICY_V1: 149 return policy->v1.filenames_encryption_mode; 150 case FSCRYPT_POLICY_V2: 151 return policy->v2.filenames_encryption_mode; 152 } 153 BUG(); 154 } 155 156 /* Return the flags (FSCRYPT_POLICY_FLAG*) of a valid encryption policy */ 157 static inline u8 158 fscrypt_policy_flags(const union fscrypt_policy *policy) 159 { 160 switch (policy->version) { 161 case FSCRYPT_POLICY_V1: 162 return policy->v1.flags; 163 case FSCRYPT_POLICY_V2: 164 return policy->v2.flags; 165 } 166 BUG(); 167 } 168 169 static inline int 170 fscrypt_policy_v2_du_bits(const struct fscrypt_policy_v2 *policy, 171 const struct inode *inode) 172 { 173 return policy->log2_data_unit_size ?: inode->i_blkbits; 174 } 175 176 static inline int 177 fscrypt_policy_du_bits(const union fscrypt_policy *policy, 178 const struct inode *inode) 179 { 180 switch (policy->version) { 181 case FSCRYPT_POLICY_V1: 182 return inode->i_blkbits; 183 case FSCRYPT_POLICY_V2: 184 return fscrypt_policy_v2_du_bits(&policy->v2, inode); 185 } 186 BUG(); 187 } 188 189 /* 190 * For encrypted symlinks, the ciphertext length is stored at the beginning 191 * of the string in little-endian format. 192 */ 193 struct fscrypt_symlink_data { 194 __le16 len; 195 char encrypted_path[]; 196 } __packed; 197 198 /** 199 * struct fscrypt_prepared_key - a key prepared for actual encryption/decryption 200 * @tfm: crypto API transform object 201 * @blk_key: key for blk-crypto 202 * 203 * Normally only one of the fields will be non-NULL. 204 */ 205 struct fscrypt_prepared_key { 206 struct crypto_skcipher *tfm; 207 #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT 208 struct blk_crypto_key *blk_key; 209 #endif 210 }; 211 212 /* 213 * fscrypt_inode_info - the "encryption key" for an inode 214 * 215 * When an encrypted file's key is made available, an instance of this struct is 216 * allocated and stored in ->i_crypt_info. Once created, it remains until the 217 * inode is evicted. 218 */ 219 struct fscrypt_inode_info { 220 221 /* The key in a form prepared for actual encryption/decryption */ 222 struct fscrypt_prepared_key ci_enc_key; 223 224 /* True if ci_enc_key should be freed when this struct is freed */ 225 u8 ci_owns_key : 1; 226 227 #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT 228 /* 229 * True if this inode will use inline encryption (blk-crypto) instead of 230 * the traditional filesystem-layer encryption. 231 */ 232 u8 ci_inlinecrypt : 1; 233 #endif 234 235 /* True if ci_dirhash_key is initialized */ 236 u8 ci_dirhash_key_initialized : 1; 237 238 /* 239 * log2 of the data unit size (granularity of contents encryption) of 240 * this file. This is computable from ci_policy and ci_inode but is 241 * cached here for efficiency. Only used for regular files. 242 */ 243 u8 ci_data_unit_bits; 244 245 /* Cached value: log2 of number of data units per FS block */ 246 u8 ci_data_units_per_block_bits; 247 248 /* Hashed inode number. Only set for IV_INO_LBLK_32 */ 249 u32 ci_hashed_ino; 250 251 /* 252 * Encryption mode used for this inode. It corresponds to either the 253 * contents or filenames encryption mode, depending on the inode type. 254 */ 255 struct fscrypt_mode *ci_mode; 256 257 /* Back-pointer to the inode */ 258 struct inode *ci_inode; 259 260 /* 261 * The master key with which this inode was unlocked (decrypted). This 262 * will be NULL if the master key was found in a process-subscribed 263 * keyring rather than in the filesystem-level keyring. 264 */ 265 struct fscrypt_master_key *ci_master_key; 266 267 /* 268 * Link in list of inodes that were unlocked with the master key. 269 * Only used when ->ci_master_key is set. 270 */ 271 struct list_head ci_master_key_link; 272 273 /* 274 * If non-NULL, then encryption is done using the master key directly 275 * and ci_enc_key will equal ci_direct_key->dk_key. 276 */ 277 struct fscrypt_direct_key *ci_direct_key; 278 279 /* 280 * This inode's hash key for filenames. This is a 128-bit SipHash-2-4 281 * key. This is only set for directories that use a keyed dirhash over 282 * the plaintext filenames -- currently just casefolded directories. 283 */ 284 siphash_key_t ci_dirhash_key; 285 286 /* The encryption policy used by this inode */ 287 union fscrypt_policy ci_policy; 288 289 /* This inode's nonce, copied from the fscrypt_context */ 290 u8 ci_nonce[FSCRYPT_FILE_NONCE_SIZE]; 291 }; 292 293 typedef enum { 294 FS_DECRYPT = 0, 295 FS_ENCRYPT, 296 } fscrypt_direction_t; 297 298 /* crypto.c */ 299 extern struct kmem_cache *fscrypt_inode_info_cachep; 300 int fscrypt_initialize(struct super_block *sb); 301 int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci, 302 fscrypt_direction_t rw, u64 index, 303 struct page *src_page, struct page *dest_page, 304 unsigned int len, unsigned int offs, 305 gfp_t gfp_flags); 306 struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags); 307 308 void __printf(3, 4) __cold 309 fscrypt_msg(const struct inode *inode, const char *level, const char *fmt, ...); 310 311 #define fscrypt_warn(inode, fmt, ...) \ 312 fscrypt_msg((inode), KERN_WARNING, fmt, ##__VA_ARGS__) 313 #define fscrypt_err(inode, fmt, ...) \ 314 fscrypt_msg((inode), KERN_ERR, fmt, ##__VA_ARGS__) 315 316 #define FSCRYPT_MAX_IV_SIZE 32 317 318 union fscrypt_iv { 319 struct { 320 /* zero-based index of data unit within the file */ 321 __le64 index; 322 323 /* per-file nonce; only set in DIRECT_KEY mode */ 324 u8 nonce[FSCRYPT_FILE_NONCE_SIZE]; 325 }; 326 u8 raw[FSCRYPT_MAX_IV_SIZE]; 327 __le64 dun[FSCRYPT_MAX_IV_SIZE / sizeof(__le64)]; 328 }; 329 330 void fscrypt_generate_iv(union fscrypt_iv *iv, u64 index, 331 const struct fscrypt_inode_info *ci); 332 333 /* 334 * Return the number of bits used by the maximum file data unit index that is 335 * possible on the given filesystem, using the given log2 data unit size. 336 */ 337 static inline int 338 fscrypt_max_file_dun_bits(const struct super_block *sb, int du_bits) 339 { 340 return fls64(sb->s_maxbytes - 1) - du_bits; 341 } 342 343 /* fname.c */ 344 bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy, 345 u32 orig_len, u32 max_len, 346 u32 *encrypted_len_ret); 347 348 /* hkdf.c */ 349 struct fscrypt_hkdf { 350 struct crypto_shash *hmac_tfm; 351 }; 352 353 int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key, 354 unsigned int master_key_size); 355 356 /* 357 * The list of contexts in which fscrypt uses HKDF. These values are used as 358 * the first byte of the HKDF application-specific info string to guarantee that 359 * info strings are never repeated between contexts. This ensures that all HKDF 360 * outputs are unique and cryptographically isolated, i.e. knowledge of one 361 * output doesn't reveal another. 362 */ 363 #define HKDF_CONTEXT_KEY_IDENTIFIER 1 /* info=<empty> */ 364 #define HKDF_CONTEXT_PER_FILE_ENC_KEY 2 /* info=file_nonce */ 365 #define HKDF_CONTEXT_DIRECT_KEY 3 /* info=mode_num */ 366 #define HKDF_CONTEXT_IV_INO_LBLK_64_KEY 4 /* info=mode_num||fs_uuid */ 367 #define HKDF_CONTEXT_DIRHASH_KEY 5 /* info=file_nonce */ 368 #define HKDF_CONTEXT_IV_INO_LBLK_32_KEY 6 /* info=mode_num||fs_uuid */ 369 #define HKDF_CONTEXT_INODE_HASH_KEY 7 /* info=<empty> */ 370 371 int fscrypt_hkdf_expand(const struct fscrypt_hkdf *hkdf, u8 context, 372 const u8 *info, unsigned int infolen, 373 u8 *okm, unsigned int okmlen); 374 375 void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf); 376 377 /* inline_crypt.c */ 378 #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT 379 int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci); 380 381 static inline bool 382 fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci) 383 { 384 return ci->ci_inlinecrypt; 385 } 386 387 int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, 388 const u8 *raw_key, 389 const struct fscrypt_inode_info *ci); 390 391 void fscrypt_destroy_inline_crypt_key(struct super_block *sb, 392 struct fscrypt_prepared_key *prep_key); 393 394 /* 395 * Check whether the crypto transform or blk-crypto key has been allocated in 396 * @prep_key, depending on which encryption implementation the file will use. 397 */ 398 static inline bool 399 fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key, 400 const struct fscrypt_inode_info *ci) 401 { 402 /* 403 * The two smp_load_acquire()'s here pair with the smp_store_release()'s 404 * in fscrypt_prepare_inline_crypt_key() and fscrypt_prepare_key(). 405 * I.e., in some cases (namely, if this prep_key is a per-mode 406 * encryption key) another task can publish blk_key or tfm concurrently, 407 * executing a RELEASE barrier. We need to use smp_load_acquire() here 408 * to safely ACQUIRE the memory the other task published. 409 */ 410 if (fscrypt_using_inline_encryption(ci)) 411 return smp_load_acquire(&prep_key->blk_key) != NULL; 412 return smp_load_acquire(&prep_key->tfm) != NULL; 413 } 414 415 #else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ 416 417 static inline int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci) 418 { 419 return 0; 420 } 421 422 static inline bool 423 fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci) 424 { 425 return false; 426 } 427 428 static inline int 429 fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, 430 const u8 *raw_key, 431 const struct fscrypt_inode_info *ci) 432 { 433 WARN_ON_ONCE(1); 434 return -EOPNOTSUPP; 435 } 436 437 static inline void 438 fscrypt_destroy_inline_crypt_key(struct super_block *sb, 439 struct fscrypt_prepared_key *prep_key) 440 { 441 } 442 443 static inline bool 444 fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key, 445 const struct fscrypt_inode_info *ci) 446 { 447 return smp_load_acquire(&prep_key->tfm) != NULL; 448 } 449 #endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ 450 451 /* keyring.c */ 452 453 /* 454 * fscrypt_master_key_secret - secret key material of an in-use master key 455 */ 456 struct fscrypt_master_key_secret { 457 458 /* 459 * For v2 policy keys: HKDF context keyed by this master key. 460 * For v1 policy keys: not set (hkdf.hmac_tfm == NULL). 461 */ 462 struct fscrypt_hkdf hkdf; 463 464 /* 465 * Size of the raw key in bytes. This remains set even if ->raw was 466 * zeroized due to no longer being needed. I.e. we still remember the 467 * size of the key even if we don't need to remember the key itself. 468 */ 469 u32 size; 470 471 /* For v1 policy keys: the raw key. Wiped for v2 policy keys. */ 472 u8 raw[FSCRYPT_MAX_KEY_SIZE]; 473 474 } __randomize_layout; 475 476 /* 477 * fscrypt_master_key - an in-use master key 478 * 479 * This represents a master encryption key which has been added to the 480 * filesystem. There are three high-level states that a key can be in: 481 * 482 * FSCRYPT_KEY_STATUS_PRESENT 483 * Key is fully usable; it can be used to unlock inodes that are encrypted 484 * with it (this includes being able to create new inodes). ->mk_present 485 * indicates whether the key is in this state. ->mk_secret exists, the key 486 * is in the keyring, and ->mk_active_refs > 0 due to ->mk_present. 487 * 488 * FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED 489 * Removal of this key has been initiated, but some inodes that were 490 * unlocked with it are still in-use. Like ABSENT, ->mk_secret is wiped, 491 * and the key can no longer be used to unlock inodes. Unlike ABSENT, the 492 * key is still in the keyring; ->mk_decrypted_inodes is nonempty; and 493 * ->mk_active_refs > 0, being equal to the size of ->mk_decrypted_inodes. 494 * 495 * This state transitions to ABSENT if ->mk_decrypted_inodes becomes empty, 496 * or to PRESENT if FS_IOC_ADD_ENCRYPTION_KEY is called again for this key. 497 * 498 * FSCRYPT_KEY_STATUS_ABSENT 499 * Key is fully removed. The key is no longer in the keyring, 500 * ->mk_decrypted_inodes is empty, ->mk_active_refs == 0, ->mk_secret is 501 * wiped, and the key can no longer be used to unlock inodes. 502 */ 503 struct fscrypt_master_key { 504 505 /* 506 * Link in ->s_master_keys->key_hashtable. 507 * Only valid if ->mk_active_refs > 0. 508 */ 509 struct hlist_node mk_node; 510 511 /* Semaphore that protects ->mk_secret, ->mk_users, and ->mk_present */ 512 struct rw_semaphore mk_sem; 513 514 /* 515 * Active and structural reference counts. An active ref guarantees 516 * that the struct continues to exist, continues to be in the keyring 517 * ->s_master_keys, and that any embedded subkeys (e.g. 518 * ->mk_direct_keys) that have been prepared continue to exist. 519 * A structural ref only guarantees that the struct continues to exist. 520 * 521 * There is one active ref associated with ->mk_present being true, and 522 * one active ref for each inode in ->mk_decrypted_inodes. 523 * 524 * There is one structural ref associated with the active refcount being 525 * nonzero. Finding a key in the keyring also takes a structural ref, 526 * which is then held temporarily while the key is operated on. 527 */ 528 refcount_t mk_active_refs; 529 refcount_t mk_struct_refs; 530 531 struct rcu_head mk_rcu_head; 532 533 /* 534 * The secret key material. Wiped as soon as it is no longer needed; 535 * for details, see the fscrypt_master_key struct comment. 536 * 537 * Locking: protected by ->mk_sem. 538 */ 539 struct fscrypt_master_key_secret mk_secret; 540 541 /* 542 * For v1 policy keys: an arbitrary key descriptor which was assigned by 543 * userspace (->descriptor). 544 * 545 * For v2 policy keys: a cryptographic hash of this key (->identifier). 546 */ 547 struct fscrypt_key_specifier mk_spec; 548 549 /* 550 * Keyring which contains a key of type 'key_type_fscrypt_user' for each 551 * user who has added this key. Normally each key will be added by just 552 * one user, but it's possible that multiple users share a key, and in 553 * that case we need to keep track of those users so that one user can't 554 * remove the key before the others want it removed too. 555 * 556 * This is NULL for v1 policy keys; those can only be added by root. 557 * 558 * Locking: protected by ->mk_sem. (We don't just rely on the keyrings 559 * subsystem semaphore ->mk_users->sem, as we need support for atomic 560 * search+insert along with proper synchronization with other fields.) 561 */ 562 struct key *mk_users; 563 564 /* 565 * List of inodes that were unlocked using this key. This allows the 566 * inodes to be evicted efficiently if the key is removed. 567 */ 568 struct list_head mk_decrypted_inodes; 569 spinlock_t mk_decrypted_inodes_lock; 570 571 /* 572 * Per-mode encryption keys for the various types of encryption policies 573 * that use them. Allocated and derived on-demand. 574 */ 575 struct fscrypt_prepared_key mk_direct_keys[FSCRYPT_MODE_MAX + 1]; 576 struct fscrypt_prepared_key mk_iv_ino_lblk_64_keys[FSCRYPT_MODE_MAX + 1]; 577 struct fscrypt_prepared_key mk_iv_ino_lblk_32_keys[FSCRYPT_MODE_MAX + 1]; 578 579 /* Hash key for inode numbers. Initialized only when needed. */ 580 siphash_key_t mk_ino_hash_key; 581 bool mk_ino_hash_key_initialized; 582 583 /* 584 * Whether this key is in the "present" state, i.e. fully usable. For 585 * details, see the fscrypt_master_key struct comment. 586 * 587 * Locking: protected by ->mk_sem, but can be read locklessly using 588 * READ_ONCE(). Writers must use WRITE_ONCE() when concurrent readers 589 * are possible. 590 */ 591 bool mk_present; 592 593 } __randomize_layout; 594 595 static inline const char *master_key_spec_type( 596 const struct fscrypt_key_specifier *spec) 597 { 598 switch (spec->type) { 599 case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR: 600 return "descriptor"; 601 case FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER: 602 return "identifier"; 603 } 604 return "[unknown]"; 605 } 606 607 static inline int master_key_spec_len(const struct fscrypt_key_specifier *spec) 608 { 609 switch (spec->type) { 610 case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR: 611 return FSCRYPT_KEY_DESCRIPTOR_SIZE; 612 case FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER: 613 return FSCRYPT_KEY_IDENTIFIER_SIZE; 614 } 615 return 0; 616 } 617 618 void fscrypt_put_master_key(struct fscrypt_master_key *mk); 619 620 void fscrypt_put_master_key_activeref(struct super_block *sb, 621 struct fscrypt_master_key *mk); 622 623 struct fscrypt_master_key * 624 fscrypt_find_master_key(struct super_block *sb, 625 const struct fscrypt_key_specifier *mk_spec); 626 627 int fscrypt_get_test_dummy_key_identifier( 628 u8 key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]); 629 630 int fscrypt_add_test_dummy_key(struct super_block *sb, 631 struct fscrypt_key_specifier *key_spec); 632 633 int fscrypt_verify_key_added(struct super_block *sb, 634 const u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]); 635 636 int __init fscrypt_init_keyring(void); 637 638 /* keysetup.c */ 639 640 struct fscrypt_mode { 641 const char *friendly_name; 642 const char *cipher_str; 643 int keysize; /* key size in bytes */ 644 int security_strength; /* security strength in bytes */ 645 int ivsize; /* IV size in bytes */ 646 int logged_cryptoapi_impl; 647 int logged_blk_crypto_native; 648 int logged_blk_crypto_fallback; 649 enum blk_crypto_mode_num blk_crypto_mode; 650 }; 651 652 extern struct fscrypt_mode fscrypt_modes[]; 653 654 int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key, 655 const u8 *raw_key, const struct fscrypt_inode_info *ci); 656 657 void fscrypt_destroy_prepared_key(struct super_block *sb, 658 struct fscrypt_prepared_key *prep_key); 659 660 int fscrypt_set_per_file_enc_key(struct fscrypt_inode_info *ci, 661 const u8 *raw_key); 662 663 int fscrypt_derive_dirhash_key(struct fscrypt_inode_info *ci, 664 const struct fscrypt_master_key *mk); 665 666 void fscrypt_hash_inode_number(struct fscrypt_inode_info *ci, 667 const struct fscrypt_master_key *mk); 668 669 int fscrypt_get_encryption_info(struct inode *inode, bool allow_unsupported); 670 671 /** 672 * fscrypt_require_key() - require an inode's encryption key 673 * @inode: the inode we need the key for 674 * 675 * If the inode is encrypted, set up its encryption key if not already done. 676 * Then require that the key be present and return -ENOKEY otherwise. 677 * 678 * No locks are needed, and the key will live as long as the struct inode --- so 679 * it won't go away from under you. 680 * 681 * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code 682 * if a problem occurred while setting up the encryption key. 683 */ 684 static inline int fscrypt_require_key(struct inode *inode) 685 { 686 if (IS_ENCRYPTED(inode)) { 687 int err = fscrypt_get_encryption_info(inode, false); 688 689 if (err) 690 return err; 691 if (!fscrypt_has_encryption_key(inode)) 692 return -ENOKEY; 693 } 694 return 0; 695 } 696 697 /* keysetup_v1.c */ 698 699 void fscrypt_put_direct_key(struct fscrypt_direct_key *dk); 700 701 int fscrypt_setup_v1_file_key(struct fscrypt_inode_info *ci, 702 const u8 *raw_master_key); 703 704 int fscrypt_setup_v1_file_key_via_subscribed_keyrings( 705 struct fscrypt_inode_info *ci); 706 707 /* policy.c */ 708 709 bool fscrypt_policies_equal(const union fscrypt_policy *policy1, 710 const union fscrypt_policy *policy2); 711 int fscrypt_policy_to_key_spec(const union fscrypt_policy *policy, 712 struct fscrypt_key_specifier *key_spec); 713 const union fscrypt_policy *fscrypt_get_dummy_policy(struct super_block *sb); 714 bool fscrypt_supported_policy(const union fscrypt_policy *policy_u, 715 const struct inode *inode); 716 int fscrypt_policy_from_context(union fscrypt_policy *policy_u, 717 const union fscrypt_context *ctx_u, 718 int ctx_size); 719 const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir); 720 721 #endif /* _FSCRYPT_PRIVATE_H */ 722