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_ADIANTUM
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 __reserved[4];
51 	u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
52 	u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
53 };
54 
55 /*
56  * fscrypt_context - the encryption context of an inode
57  *
58  * This is the on-disk equivalent of an fscrypt_policy, stored alongside each
59  * encrypted file usually in a hidden extended attribute.  It contains the
60  * fields from the fscrypt_policy, in order to identify the encryption algorithm
61  * and key with which the file is encrypted.  It also contains a nonce that was
62  * randomly generated by fscrypt itself; this is used as KDF input or as a tweak
63  * to cause different files to be encrypted differently.
64  */
65 union fscrypt_context {
66 	u8 version;
67 	struct fscrypt_context_v1 v1;
68 	struct fscrypt_context_v2 v2;
69 };
70 
71 /*
72  * Return the size expected for the given fscrypt_context based on its version
73  * number, or 0 if the context version is unrecognized.
74  */
fscrypt_context_size(const union fscrypt_context * ctx)75 static inline int fscrypt_context_size(const union fscrypt_context *ctx)
76 {
77 	switch (ctx->version) {
78 	case FSCRYPT_CONTEXT_V1:
79 		BUILD_BUG_ON(sizeof(ctx->v1) != 28);
80 		return sizeof(ctx->v1);
81 	case FSCRYPT_CONTEXT_V2:
82 		BUILD_BUG_ON(sizeof(ctx->v2) != 40);
83 		return sizeof(ctx->v2);
84 	}
85 	return 0;
86 }
87 
88 /* Check whether an fscrypt_context has a recognized version number and size */
fscrypt_context_is_valid(const union fscrypt_context * ctx,int ctx_size)89 static inline bool fscrypt_context_is_valid(const union fscrypt_context *ctx,
90 					    int ctx_size)
91 {
92 	return ctx_size >= 1 && ctx_size == fscrypt_context_size(ctx);
93 }
94 
95 /* Retrieve the context's nonce, assuming the context was already validated */
fscrypt_context_nonce(const union fscrypt_context * ctx)96 static inline const u8 *fscrypt_context_nonce(const union fscrypt_context *ctx)
97 {
98 	switch (ctx->version) {
99 	case FSCRYPT_CONTEXT_V1:
100 		return ctx->v1.nonce;
101 	case FSCRYPT_CONTEXT_V2:
102 		return ctx->v2.nonce;
103 	}
104 	WARN_ON(1);
105 	return NULL;
106 }
107 
108 union fscrypt_policy {
109 	u8 version;
110 	struct fscrypt_policy_v1 v1;
111 	struct fscrypt_policy_v2 v2;
112 };
113 
114 /*
115  * Return the size expected for the given fscrypt_policy based on its version
116  * number, or 0 if the policy version is unrecognized.
117  */
fscrypt_policy_size(const union fscrypt_policy * policy)118 static inline int fscrypt_policy_size(const union fscrypt_policy *policy)
119 {
120 	switch (policy->version) {
121 	case FSCRYPT_POLICY_V1:
122 		return sizeof(policy->v1);
123 	case FSCRYPT_POLICY_V2:
124 		return sizeof(policy->v2);
125 	}
126 	return 0;
127 }
128 
129 /* Return the contents encryption mode of a valid encryption policy */
130 static inline u8
fscrypt_policy_contents_mode(const union fscrypt_policy * policy)131 fscrypt_policy_contents_mode(const union fscrypt_policy *policy)
132 {
133 	switch (policy->version) {
134 	case FSCRYPT_POLICY_V1:
135 		return policy->v1.contents_encryption_mode;
136 	case FSCRYPT_POLICY_V2:
137 		return policy->v2.contents_encryption_mode;
138 	}
139 	BUG();
140 }
141 
142 /* Return the filenames encryption mode of a valid encryption policy */
143 static inline u8
fscrypt_policy_fnames_mode(const union fscrypt_policy * policy)144 fscrypt_policy_fnames_mode(const union fscrypt_policy *policy)
145 {
146 	switch (policy->version) {
147 	case FSCRYPT_POLICY_V1:
148 		return policy->v1.filenames_encryption_mode;
149 	case FSCRYPT_POLICY_V2:
150 		return policy->v2.filenames_encryption_mode;
151 	}
152 	BUG();
153 }
154 
155 /* Return the flags (FSCRYPT_POLICY_FLAG*) of a valid encryption policy */
156 static inline u8
fscrypt_policy_flags(const union fscrypt_policy * policy)157 fscrypt_policy_flags(const union fscrypt_policy *policy)
158 {
159 	switch (policy->version) {
160 	case FSCRYPT_POLICY_V1:
161 		return policy->v1.flags;
162 	case FSCRYPT_POLICY_V2:
163 		return policy->v2.flags;
164 	}
165 	BUG();
166 }
167 
168 /*
169  * For encrypted symlinks, the ciphertext length is stored at the beginning
170  * of the string in little-endian format.
171  */
172 struct fscrypt_symlink_data {
173 	__le16 len;
174 	char encrypted_path[1];
175 } __packed;
176 
177 /**
178  * struct fscrypt_prepared_key - a key prepared for actual encryption/decryption
179  * @tfm: crypto API transform object
180  * @blk_key: key for blk-crypto
181  *
182  * Normally only one of the fields will be non-NULL.
183  */
184 struct fscrypt_prepared_key {
185 	struct crypto_skcipher *tfm;
186 #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
187 	struct fscrypt_blk_crypto_key *blk_key;
188 #endif
189 };
190 
191 /*
192  * fscrypt_info - the "encryption key" for an inode
193  *
194  * When an encrypted file's key is made available, an instance of this struct is
195  * allocated and stored in ->i_crypt_info.  Once created, it remains until the
196  * inode is evicted.
197  */
198 struct fscrypt_info {
199 
200 	/* The key in a form prepared for actual encryption/decryption */
201 	struct fscrypt_prepared_key ci_enc_key;
202 
203 	/* True if ci_enc_key should be freed when this fscrypt_info is freed */
204 	bool ci_owns_key;
205 
206 #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
207 	/*
208 	 * True if this inode will use inline encryption (blk-crypto) instead of
209 	 * the traditional filesystem-layer encryption.
210 	 */
211 	bool ci_inlinecrypt;
212 #endif
213 
214 	/*
215 	 * Encryption mode used for this inode.  It corresponds to either the
216 	 * contents or filenames encryption mode, depending on the inode type.
217 	 */
218 	struct fscrypt_mode *ci_mode;
219 
220 	/* Back-pointer to the inode */
221 	struct inode *ci_inode;
222 
223 	/*
224 	 * The master key with which this inode was unlocked (decrypted).  This
225 	 * will be NULL if the master key was found in a process-subscribed
226 	 * keyring rather than in the filesystem-level keyring.
227 	 */
228 	struct key *ci_master_key;
229 
230 	/*
231 	 * Link in list of inodes that were unlocked with the master key.
232 	 * Only used when ->ci_master_key is set.
233 	 */
234 	struct list_head ci_master_key_link;
235 
236 	/*
237 	 * If non-NULL, then encryption is done using the master key directly
238 	 * and ci_enc_key will equal ci_direct_key->dk_key.
239 	 */
240 	struct fscrypt_direct_key *ci_direct_key;
241 
242 	/*
243 	 * This inode's hash key for filenames.  This is a 128-bit SipHash-2-4
244 	 * key.  This is only set for directories that use a keyed dirhash over
245 	 * the plaintext filenames -- currently just casefolded directories.
246 	 */
247 	siphash_key_t ci_dirhash_key;
248 	bool ci_dirhash_key_initialized;
249 
250 	/* The encryption policy used by this inode */
251 	union fscrypt_policy ci_policy;
252 
253 	/* This inode's nonce, copied from the fscrypt_context */
254 	u8 ci_nonce[FSCRYPT_FILE_NONCE_SIZE];
255 
256 	/* Hashed inode number.  Only set for IV_INO_LBLK_32 */
257 	u32 ci_hashed_ino;
258 };
259 
260 typedef enum {
261 	FS_DECRYPT = 0,
262 	FS_ENCRYPT,
263 } fscrypt_direction_t;
264 
265 /* crypto.c */
266 extern struct kmem_cache *fscrypt_info_cachep;
267 int fscrypt_initialize(unsigned int cop_flags);
268 int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw,
269 			u64 lblk_num, struct page *src_page,
270 			struct page *dest_page, unsigned int len,
271 			unsigned int offs, gfp_t gfp_flags);
272 struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags);
273 
274 void __printf(3, 4) __cold
275 fscrypt_msg(const struct inode *inode, const char *level, const char *fmt, ...);
276 
277 #define fscrypt_warn(inode, fmt, ...)		\
278 	fscrypt_msg((inode), KERN_WARNING, fmt, ##__VA_ARGS__)
279 #define fscrypt_err(inode, fmt, ...)		\
280 	fscrypt_msg((inode), KERN_ERR, fmt, ##__VA_ARGS__)
281 
282 #define FSCRYPT_MAX_IV_SIZE	32
283 
284 union fscrypt_iv {
285 	struct {
286 		/* logical block number within the file */
287 		__le64 lblk_num;
288 
289 		/* per-file nonce; only set in DIRECT_KEY mode */
290 		u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
291 	};
292 	u8 raw[FSCRYPT_MAX_IV_SIZE];
293 	__le64 dun[FSCRYPT_MAX_IV_SIZE / sizeof(__le64)];
294 };
295 
296 void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num,
297 			 const struct fscrypt_info *ci);
298 
299 /* fname.c */
300 int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
301 			  u8 *out, unsigned int olen);
302 bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
303 				  u32 orig_len, u32 max_len,
304 				  u32 *encrypted_len_ret);
305 
306 /* hkdf.c */
307 
308 struct fscrypt_hkdf {
309 	struct crypto_shash *hmac_tfm;
310 };
311 
312 int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key,
313 		      unsigned int master_key_size);
314 
315 /*
316  * The list of contexts in which fscrypt uses HKDF.  These values are used as
317  * the first byte of the HKDF application-specific info string to guarantee that
318  * info strings are never repeated between contexts.  This ensures that all HKDF
319  * outputs are unique and cryptographically isolated, i.e. knowledge of one
320  * output doesn't reveal another.
321  */
322 #define HKDF_CONTEXT_KEY_IDENTIFIER	1 /* info=<empty>		*/
323 #define HKDF_CONTEXT_PER_FILE_ENC_KEY	2 /* info=file_nonce		*/
324 #define HKDF_CONTEXT_DIRECT_KEY		3 /* info=mode_num		*/
325 #define HKDF_CONTEXT_IV_INO_LBLK_64_KEY	4 /* info=mode_num||fs_uuid	*/
326 #define HKDF_CONTEXT_DIRHASH_KEY	5 /* info=file_nonce		*/
327 #define HKDF_CONTEXT_IV_INO_LBLK_32_KEY	6 /* info=mode_num||fs_uuid	*/
328 #define HKDF_CONTEXT_INODE_HASH_KEY	7 /* info=<empty>		*/
329 
330 int fscrypt_hkdf_expand(const struct fscrypt_hkdf *hkdf, u8 context,
331 			const u8 *info, unsigned int infolen,
332 			u8 *okm, unsigned int okmlen);
333 
334 void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf);
335 
336 /* inline_crypt.c */
337 #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
338 int fscrypt_select_encryption_impl(struct fscrypt_info *ci);
339 
340 static inline bool
fscrypt_using_inline_encryption(const struct fscrypt_info * ci)341 fscrypt_using_inline_encryption(const struct fscrypt_info *ci)
342 {
343 	return ci->ci_inlinecrypt;
344 }
345 
346 int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
347 				     const u8 *raw_key,
348 				     const struct fscrypt_info *ci);
349 
350 void fscrypt_destroy_inline_crypt_key(struct fscrypt_prepared_key *prep_key);
351 
352 /*
353  * Check whether the crypto transform or blk-crypto key has been allocated in
354  * @prep_key, depending on which encryption implementation the file will use.
355  */
356 static inline bool
fscrypt_is_key_prepared(struct fscrypt_prepared_key * prep_key,const struct fscrypt_info * ci)357 fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
358 			const struct fscrypt_info *ci)
359 {
360 	/*
361 	 * The two smp_load_acquire()'s here pair with the smp_store_release()'s
362 	 * in fscrypt_prepare_inline_crypt_key() and fscrypt_prepare_key().
363 	 * I.e., in some cases (namely, if this prep_key is a per-mode
364 	 * encryption key) another task can publish blk_key or tfm concurrently,
365 	 * executing a RELEASE barrier.  We need to use smp_load_acquire() here
366 	 * to safely ACQUIRE the memory the other task published.
367 	 */
368 	if (fscrypt_using_inline_encryption(ci))
369 		return smp_load_acquire(&prep_key->blk_key) != NULL;
370 	return smp_load_acquire(&prep_key->tfm) != NULL;
371 }
372 
373 #else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
374 
fscrypt_select_encryption_impl(struct fscrypt_info * ci)375 static inline int fscrypt_select_encryption_impl(struct fscrypt_info *ci)
376 {
377 	return 0;
378 }
379 
380 static inline bool
fscrypt_using_inline_encryption(const struct fscrypt_info * ci)381 fscrypt_using_inline_encryption(const struct fscrypt_info *ci)
382 {
383 	return false;
384 }
385 
386 static inline int
fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key * prep_key,const u8 * raw_key,const struct fscrypt_info * ci)387 fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
388 				 const u8 *raw_key,
389 				 const struct fscrypt_info *ci)
390 {
391 	WARN_ON(1);
392 	return -EOPNOTSUPP;
393 }
394 
395 static inline void
fscrypt_destroy_inline_crypt_key(struct fscrypt_prepared_key * prep_key)396 fscrypt_destroy_inline_crypt_key(struct fscrypt_prepared_key *prep_key)
397 {
398 }
399 
400 static inline bool
fscrypt_is_key_prepared(struct fscrypt_prepared_key * prep_key,const struct fscrypt_info * ci)401 fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
402 			const struct fscrypt_info *ci)
403 {
404 	return smp_load_acquire(&prep_key->tfm) != NULL;
405 }
406 #endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
407 
408 /* keyring.c */
409 
410 /*
411  * fscrypt_master_key_secret - secret key material of an in-use master key
412  */
413 struct fscrypt_master_key_secret {
414 
415 	/*
416 	 * For v2 policy keys: HKDF context keyed by this master key.
417 	 * For v1 policy keys: not set (hkdf.hmac_tfm == NULL).
418 	 */
419 	struct fscrypt_hkdf	hkdf;
420 
421 	/*
422 	 * Size of the raw key in bytes.  This remains set even if ->raw was
423 	 * zeroized due to no longer being needed.  I.e. we still remember the
424 	 * size of the key even if we don't need to remember the key itself.
425 	 */
426 	u32			size;
427 
428 	/* For v1 policy keys: the raw key.  Wiped for v2 policy keys. */
429 	u8			raw[FSCRYPT_MAX_KEY_SIZE];
430 
431 } __randomize_layout;
432 
433 /*
434  * fscrypt_master_key - an in-use master key
435  *
436  * This represents a master encryption key which has been added to the
437  * filesystem and can be used to "unlock" the encrypted files which were
438  * encrypted with it.
439  */
440 struct fscrypt_master_key {
441 
442 	/*
443 	 * The secret key material.  After FS_IOC_REMOVE_ENCRYPTION_KEY is
444 	 * executed, this is wiped and no new inodes can be unlocked with this
445 	 * key; however, there may still be inodes in ->mk_decrypted_inodes
446 	 * which could not be evicted.  As long as some inodes still remain,
447 	 * FS_IOC_REMOVE_ENCRYPTION_KEY can be retried, or
448 	 * FS_IOC_ADD_ENCRYPTION_KEY can add the secret again.
449 	 *
450 	 * Locking: protected by this master key's key->sem.
451 	 */
452 	struct fscrypt_master_key_secret	mk_secret;
453 
454 	/*
455 	 * For v1 policy keys: an arbitrary key descriptor which was assigned by
456 	 * userspace (->descriptor).
457 	 *
458 	 * For v2 policy keys: a cryptographic hash of this key (->identifier).
459 	 */
460 	struct fscrypt_key_specifier		mk_spec;
461 
462 	/*
463 	 * Keyring which contains a key of type 'key_type_fscrypt_user' for each
464 	 * user who has added this key.  Normally each key will be added by just
465 	 * one user, but it's possible that multiple users share a key, and in
466 	 * that case we need to keep track of those users so that one user can't
467 	 * remove the key before the others want it removed too.
468 	 *
469 	 * This is NULL for v1 policy keys; those can only be added by root.
470 	 *
471 	 * Locking: in addition to this keyring's own semaphore, this is
472 	 * protected by this master key's key->sem, so we can do atomic
473 	 * search+insert.  It can also be searched without taking any locks, but
474 	 * in that case the returned key may have already been removed.
475 	 */
476 	struct key		*mk_users;
477 
478 	/*
479 	 * Length of ->mk_decrypted_inodes, plus one if mk_secret is present.
480 	 * Once this goes to 0, the master key is removed from ->s_master_keys.
481 	 * The 'struct fscrypt_master_key' will continue to live as long as the
482 	 * 'struct key' whose payload it is, but we won't let this reference
483 	 * count rise again.
484 	 */
485 	refcount_t		mk_refcount;
486 
487 	/*
488 	 * List of inodes that were unlocked using this key.  This allows the
489 	 * inodes to be evicted efficiently if the key is removed.
490 	 */
491 	struct list_head	mk_decrypted_inodes;
492 	spinlock_t		mk_decrypted_inodes_lock;
493 
494 	/*
495 	 * Per-mode encryption keys for the various types of encryption policies
496 	 * that use them.  Allocated and derived on-demand.
497 	 */
498 	struct fscrypt_prepared_key mk_direct_keys[FSCRYPT_MODE_MAX + 1];
499 	struct fscrypt_prepared_key mk_iv_ino_lblk_64_keys[FSCRYPT_MODE_MAX + 1];
500 	struct fscrypt_prepared_key mk_iv_ino_lblk_32_keys[FSCRYPT_MODE_MAX + 1];
501 
502 	/* Hash key for inode numbers.  Initialized only when needed. */
503 	siphash_key_t		mk_ino_hash_key;
504 	bool			mk_ino_hash_key_initialized;
505 
506 } __randomize_layout;
507 
508 static inline bool
is_master_key_secret_present(const struct fscrypt_master_key_secret * secret)509 is_master_key_secret_present(const struct fscrypt_master_key_secret *secret)
510 {
511 	/*
512 	 * The READ_ONCE() is only necessary for fscrypt_drop_inode() and
513 	 * fscrypt_key_describe().  These run in atomic context, so they can't
514 	 * take the key semaphore and thus 'secret' can change concurrently
515 	 * which would be a data race.  But they only need to know whether the
516 	 * secret *was* present at the time of check, so READ_ONCE() suffices.
517 	 */
518 	return READ_ONCE(secret->size) != 0;
519 }
520 
master_key_spec_type(const struct fscrypt_key_specifier * spec)521 static inline const char *master_key_spec_type(
522 				const struct fscrypt_key_specifier *spec)
523 {
524 	switch (spec->type) {
525 	case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR:
526 		return "descriptor";
527 	case FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER:
528 		return "identifier";
529 	}
530 	return "[unknown]";
531 }
532 
master_key_spec_len(const struct fscrypt_key_specifier * spec)533 static inline int master_key_spec_len(const struct fscrypt_key_specifier *spec)
534 {
535 	switch (spec->type) {
536 	case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR:
537 		return FSCRYPT_KEY_DESCRIPTOR_SIZE;
538 	case FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER:
539 		return FSCRYPT_KEY_IDENTIFIER_SIZE;
540 	}
541 	return 0;
542 }
543 
544 struct key *
545 fscrypt_find_master_key(struct super_block *sb,
546 			const struct fscrypt_key_specifier *mk_spec);
547 
548 int fscrypt_get_test_dummy_key_identifier(
549 			  u8 key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]);
550 
551 int fscrypt_verify_key_added(struct super_block *sb,
552 			     const u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]);
553 
554 int __init fscrypt_init_keyring(void);
555 
556 /* keysetup.c */
557 
558 struct fscrypt_mode {
559 	const char *friendly_name;
560 	const char *cipher_str;
561 	int keysize;		/* key size in bytes */
562 	int security_strength;	/* security strength in bytes */
563 	int ivsize;		/* IV size in bytes */
564 	int logged_cryptoapi_impl;
565 	int logged_blk_crypto_native;
566 	int logged_blk_crypto_fallback;
567 	enum blk_crypto_mode_num blk_crypto_mode;
568 };
569 
570 extern struct fscrypt_mode fscrypt_modes[];
571 
572 int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key,
573 			const u8 *raw_key, const struct fscrypt_info *ci);
574 
575 void fscrypt_destroy_prepared_key(struct fscrypt_prepared_key *prep_key);
576 
577 int fscrypt_set_per_file_enc_key(struct fscrypt_info *ci, const u8 *raw_key);
578 
579 int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
580 			       const struct fscrypt_master_key *mk);
581 
582 void fscrypt_hash_inode_number(struct fscrypt_info *ci,
583 			       const struct fscrypt_master_key *mk);
584 
585 int fscrypt_get_encryption_info(struct inode *inode, bool allow_unsupported);
586 
587 /**
588  * fscrypt_require_key() - require an inode's encryption key
589  * @inode: the inode we need the key for
590  *
591  * If the inode is encrypted, set up its encryption key if not already done.
592  * Then require that the key be present and return -ENOKEY otherwise.
593  *
594  * No locks are needed, and the key will live as long as the struct inode --- so
595  * it won't go away from under you.
596  *
597  * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
598  * if a problem occurred while setting up the encryption key.
599  */
fscrypt_require_key(struct inode * inode)600 static inline int fscrypt_require_key(struct inode *inode)
601 {
602 	if (IS_ENCRYPTED(inode)) {
603 		int err = fscrypt_get_encryption_info(inode, false);
604 
605 		if (err)
606 			return err;
607 		if (!fscrypt_has_encryption_key(inode))
608 			return -ENOKEY;
609 	}
610 	return 0;
611 }
612 
613 /* keysetup_v1.c */
614 
615 void fscrypt_put_direct_key(struct fscrypt_direct_key *dk);
616 
617 int fscrypt_setup_v1_file_key(struct fscrypt_info *ci,
618 			      const u8 *raw_master_key);
619 
620 int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci);
621 
622 /* policy.c */
623 
624 bool fscrypt_policies_equal(const union fscrypt_policy *policy1,
625 			    const union fscrypt_policy *policy2);
626 int fscrypt_policy_to_key_spec(const union fscrypt_policy *policy,
627 			       struct fscrypt_key_specifier *key_spec);
628 bool fscrypt_supported_policy(const union fscrypt_policy *policy_u,
629 			      const struct inode *inode);
630 int fscrypt_policy_from_context(union fscrypt_policy *policy_u,
631 				const union fscrypt_context *ctx_u,
632 				int ctx_size);
633 const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir);
634 
635 #endif /* _FSCRYPT_PRIVATE_H */
636