Line data Source code
1 : /* SPDX-License-Identifier: GPL-2.0 */
2 : /*
3 : * fscrypt.h: declarations for per-file encryption
4 : *
5 : * Filesystems that implement per-file encryption must include this header
6 : * file.
7 : *
8 : * Copyright (C) 2015, Google, Inc.
9 : *
10 : * Written by Michael Halcrow, 2015.
11 : * Modified by Jaegeuk Kim, 2015.
12 : */
13 : #ifndef _LINUX_FSCRYPT_H
14 : #define _LINUX_FSCRYPT_H
15 :
16 : #include <linux/fs.h>
17 : #include <linux/mm.h>
18 : #include <linux/slab.h>
19 : #include <uapi/linux/fscrypt.h>
20 :
21 : /*
22 : * The lengths of all file contents blocks must be divisible by this value.
23 : * This is needed to ensure that all contents encryption modes will work, as
24 : * some of the supported modes don't support arbitrarily byte-aligned messages.
25 : *
26 : * Since the needed alignment is 16 bytes, most filesystems will meet this
27 : * requirement naturally, as typical block sizes are powers of 2. However, if a
28 : * filesystem can generate arbitrarily byte-aligned block lengths (e.g., via
29 : * compression), then it will need to pad to this alignment before encryption.
30 : */
31 : #define FSCRYPT_CONTENTS_ALIGNMENT 16
32 :
33 : union fscrypt_policy;
34 : struct fscrypt_info;
35 : struct fs_parameter;
36 : struct seq_file;
37 :
38 : struct fscrypt_str {
39 : unsigned char *name;
40 : u32 len;
41 : };
42 :
43 : struct fscrypt_name {
44 : const struct qstr *usr_fname;
45 : struct fscrypt_str disk_name;
46 : u32 hash;
47 : u32 minor_hash;
48 : struct fscrypt_str crypto_buf;
49 : bool is_nokey_name;
50 : };
51 :
52 : #define FSTR_INIT(n, l) { .name = n, .len = l }
53 : #define FSTR_TO_QSTR(f) QSTR_INIT((f)->name, (f)->len)
54 : #define fname_name(p) ((p)->disk_name.name)
55 : #define fname_len(p) ((p)->disk_name.len)
56 :
57 : /* Maximum value for the third parameter of fscrypt_operations.set_context(). */
58 : #define FSCRYPT_SET_CONTEXT_MAX_SIZE 40
59 :
60 : #ifdef CONFIG_FS_ENCRYPTION
61 :
62 : /*
63 : * If set, the fscrypt bounce page pool won't be allocated (unless another
64 : * filesystem needs it). Set this if the filesystem always uses its own bounce
65 : * pages for writes and therefore won't need the fscrypt bounce page pool.
66 : */
67 : #define FS_CFLG_OWN_PAGES (1U << 1)
68 :
69 : /* Crypto operations for filesystems */
70 : struct fscrypt_operations {
71 :
72 : /* Set of optional flags; see above for allowed flags */
73 : unsigned int flags;
74 :
75 : /*
76 : * If set, this is a filesystem-specific key description prefix that
77 : * will be accepted for "logon" keys for v1 fscrypt policies, in
78 : * addition to the generic prefix "fscrypt:". This functionality is
79 : * deprecated, so new filesystems shouldn't set this field.
80 : */
81 : const char *key_prefix;
82 :
83 : /*
84 : * Get the fscrypt context of the given inode.
85 : *
86 : * @inode: the inode whose context to get
87 : * @ctx: the buffer into which to get the context
88 : * @len: length of the @ctx buffer in bytes
89 : *
90 : * Return: On success, returns the length of the context in bytes; this
91 : * may be less than @len. On failure, returns -ENODATA if the
92 : * inode doesn't have a context, -ERANGE if the context is
93 : * longer than @len, or another -errno code.
94 : */
95 : int (*get_context)(struct inode *inode, void *ctx, size_t len);
96 :
97 : /*
98 : * Set an fscrypt context on the given inode.
99 : *
100 : * @inode: the inode whose context to set. The inode won't already have
101 : * an fscrypt context.
102 : * @ctx: the context to set
103 : * @len: length of @ctx in bytes (at most FSCRYPT_SET_CONTEXT_MAX_SIZE)
104 : * @fs_data: If called from fscrypt_set_context(), this will be the
105 : * value the filesystem passed to fscrypt_set_context().
106 : * Otherwise (i.e. when called from
107 : * FS_IOC_SET_ENCRYPTION_POLICY) this will be NULL.
108 : *
109 : * i_rwsem will be held for write.
110 : *
111 : * Return: 0 on success, -errno on failure.
112 : */
113 : int (*set_context)(struct inode *inode, const void *ctx, size_t len,
114 : void *fs_data);
115 :
116 : /*
117 : * Get the dummy fscrypt policy in use on the filesystem (if any).
118 : *
119 : * Filesystems only need to implement this function if they support the
120 : * test_dummy_encryption mount option.
121 : *
122 : * Return: A pointer to the dummy fscrypt policy, if the filesystem is
123 : * mounted with test_dummy_encryption; otherwise NULL.
124 : */
125 : const union fscrypt_policy *(*get_dummy_policy)(struct super_block *sb);
126 :
127 : /*
128 : * Check whether a directory is empty. i_rwsem will be held for write.
129 : */
130 : bool (*empty_dir)(struct inode *inode);
131 :
132 : /*
133 : * Check whether the filesystem's inode numbers and UUID are stable,
134 : * meaning that they will never be changed even by offline operations
135 : * such as filesystem shrinking and therefore can be used in the
136 : * encryption without the possibility of files becoming unreadable.
137 : *
138 : * Filesystems only need to implement this function if they want to
139 : * support the FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64} flags. These
140 : * flags are designed to work around the limitations of UFS and eMMC
141 : * inline crypto hardware, and they shouldn't be used in scenarios where
142 : * such hardware isn't being used.
143 : *
144 : * Leaving this NULL is equivalent to always returning false.
145 : */
146 : bool (*has_stable_inodes)(struct super_block *sb);
147 :
148 : /*
149 : * Get the number of bits that the filesystem uses to represent inode
150 : * numbers and file logical block numbers.
151 : *
152 : * By default, both of these are assumed to be 64-bit. This function
153 : * can be implemented to declare that either or both of these numbers is
154 : * shorter, which may allow the use of the
155 : * FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64} flags and/or the use of
156 : * inline crypto hardware whose maximum DUN length is less than 64 bits
157 : * (e.g., eMMC v5.2 spec compliant hardware). This function only needs
158 : * to be implemented if support for one of these features is needed.
159 : */
160 : void (*get_ino_and_lblk_bits)(struct super_block *sb,
161 : int *ino_bits_ret, int *lblk_bits_ret);
162 :
163 : /*
164 : * Return an array of pointers to the block devices to which the
165 : * filesystem may write encrypted file contents, NULL if the filesystem
166 : * only has a single such block device, or an ERR_PTR() on error.
167 : *
168 : * On successful non-NULL return, *num_devs is set to the number of
169 : * devices in the returned array. The caller must free the returned
170 : * array using kfree().
171 : *
172 : * If the filesystem can use multiple block devices (other than block
173 : * devices that aren't used for encrypted file contents, such as
174 : * external journal devices), and wants to support inline encryption,
175 : * then it must implement this function. Otherwise it's not needed.
176 : */
177 : struct block_device **(*get_devices)(struct super_block *sb,
178 : unsigned int *num_devs);
179 : };
180 :
181 : static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode)
182 : {
183 : /*
184 : * Pairs with the cmpxchg_release() in fscrypt_setup_encryption_info().
185 : * I.e., another task may publish ->i_crypt_info concurrently, executing
186 : * a RELEASE barrier. We need to use smp_load_acquire() here to safely
187 : * ACQUIRE the memory the other task published.
188 : */
189 : return smp_load_acquire(&inode->i_crypt_info);
190 : }
191 :
192 : /**
193 : * fscrypt_needs_contents_encryption() - check whether an inode needs
194 : * contents encryption
195 : * @inode: the inode to check
196 : *
197 : * Return: %true iff the inode is an encrypted regular file and the kernel was
198 : * built with fscrypt support.
199 : *
200 : * If you need to know whether the encrypt bit is set even when the kernel was
201 : * built without fscrypt support, you must use IS_ENCRYPTED() directly instead.
202 : */
203 : static inline bool fscrypt_needs_contents_encryption(const struct inode *inode)
204 : {
205 : return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode);
206 : }
207 :
208 : /*
209 : * When d_splice_alias() moves a directory's no-key alias to its plaintext alias
210 : * as a result of the encryption key being added, DCACHE_NOKEY_NAME must be
211 : * cleared. Note that we don't have to support arbitrary moves of this flag
212 : * because fscrypt doesn't allow no-key names to be the source or target of a
213 : * rename().
214 : */
215 : static inline void fscrypt_handle_d_move(struct dentry *dentry)
216 : {
217 : dentry->d_flags &= ~DCACHE_NOKEY_NAME;
218 : }
219 :
220 : /**
221 : * fscrypt_is_nokey_name() - test whether a dentry is a no-key name
222 : * @dentry: the dentry to check
223 : *
224 : * This returns true if the dentry is a no-key dentry. A no-key dentry is a
225 : * dentry that was created in an encrypted directory that hasn't had its
226 : * encryption key added yet. Such dentries may be either positive or negative.
227 : *
228 : * When a filesystem is asked to create a new filename in an encrypted directory
229 : * and the new filename's dentry is a no-key dentry, it must fail the operation
230 : * with ENOKEY. This includes ->create(), ->mkdir(), ->mknod(), ->symlink(),
231 : * ->rename(), and ->link(). (However, ->rename() and ->link() are already
232 : * handled by fscrypt_prepare_rename() and fscrypt_prepare_link().)
233 : *
234 : * This is necessary because creating a filename requires the directory's
235 : * encryption key, but just checking for the key on the directory inode during
236 : * the final filesystem operation doesn't guarantee that the key was available
237 : * during the preceding dentry lookup. And the key must have already been
238 : * available during the dentry lookup in order for it to have been checked
239 : * whether the filename already exists in the directory and for the new file's
240 : * dentry not to be invalidated due to it incorrectly having the no-key flag.
241 : *
242 : * Return: %true if the dentry is a no-key name
243 : */
244 : static inline bool fscrypt_is_nokey_name(const struct dentry *dentry)
245 : {
246 : return dentry->d_flags & DCACHE_NOKEY_NAME;
247 : }
248 :
249 : /* crypto.c */
250 : void fscrypt_enqueue_decrypt_work(struct work_struct *);
251 :
252 : struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
253 : unsigned int len,
254 : unsigned int offs,
255 : gfp_t gfp_flags);
256 : int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page,
257 : unsigned int len, unsigned int offs,
258 : u64 lblk_num, gfp_t gfp_flags);
259 :
260 : int fscrypt_decrypt_pagecache_blocks(struct folio *folio, size_t len,
261 : size_t offs);
262 : int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page,
263 : unsigned int len, unsigned int offs,
264 : u64 lblk_num);
265 :
266 : static inline bool fscrypt_is_bounce_page(struct page *page)
267 : {
268 : return page->mapping == NULL;
269 : }
270 :
271 : static inline struct page *fscrypt_pagecache_page(struct page *bounce_page)
272 : {
273 : return (struct page *)page_private(bounce_page);
274 : }
275 :
276 : static inline bool fscrypt_is_bounce_folio(struct folio *folio)
277 : {
278 : return folio->mapping == NULL;
279 : }
280 :
281 : static inline struct folio *fscrypt_pagecache_folio(struct folio *bounce_folio)
282 : {
283 : return bounce_folio->private;
284 : }
285 :
286 : void fscrypt_free_bounce_page(struct page *bounce_page);
287 :
288 : /* policy.c */
289 : int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg);
290 : int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg);
291 : int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *arg);
292 : int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg);
293 : int fscrypt_has_permitted_context(struct inode *parent, struct inode *child);
294 : int fscrypt_context_for_new_inode(void *ctx, struct inode *inode);
295 : int fscrypt_set_context(struct inode *inode, void *fs_data);
296 :
297 : struct fscrypt_dummy_policy {
298 : const union fscrypt_policy *policy;
299 : };
300 :
301 : int fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param,
302 : struct fscrypt_dummy_policy *dummy_policy);
303 : bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1,
304 : const struct fscrypt_dummy_policy *p2);
305 : void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep,
306 : struct super_block *sb);
307 : static inline bool
308 : fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy)
309 : {
310 : return dummy_policy->policy != NULL;
311 : }
312 : static inline void
313 : fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy)
314 : {
315 : kfree(dummy_policy->policy);
316 : dummy_policy->policy = NULL;
317 : }
318 :
319 : /* keyring.c */
320 : void fscrypt_destroy_keyring(struct super_block *sb);
321 : int fscrypt_ioctl_add_key(struct file *filp, void __user *arg);
322 : int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg);
323 : int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *arg);
324 : int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg);
325 :
326 : /* keysetup.c */
327 : int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode,
328 : bool *encrypt_ret);
329 : void fscrypt_put_encryption_info(struct inode *inode);
330 : void fscrypt_free_inode(struct inode *inode);
331 : int fscrypt_drop_inode(struct inode *inode);
332 :
333 : /* fname.c */
334 : int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
335 : u8 *out, unsigned int olen);
336 : bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len,
337 : u32 max_len, u32 *encrypted_len_ret);
338 : int fscrypt_setup_filename(struct inode *inode, const struct qstr *iname,
339 : int lookup, struct fscrypt_name *fname);
340 :
341 : static inline void fscrypt_free_filename(struct fscrypt_name *fname)
342 : {
343 : kfree(fname->crypto_buf.name);
344 : }
345 :
346 : int fscrypt_fname_alloc_buffer(u32 max_encrypted_len,
347 : struct fscrypt_str *crypto_str);
348 : void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str);
349 : int fscrypt_fname_disk_to_usr(const struct inode *inode,
350 : u32 hash, u32 minor_hash,
351 : const struct fscrypt_str *iname,
352 : struct fscrypt_str *oname);
353 : bool fscrypt_match_name(const struct fscrypt_name *fname,
354 : const u8 *de_name, u32 de_name_len);
355 : u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name);
356 : int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags);
357 :
358 : /* bio.c */
359 : bool fscrypt_decrypt_bio(struct bio *bio);
360 : int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
361 : sector_t pblk, unsigned int len);
362 :
363 : /* hooks.c */
364 : int fscrypt_file_open(struct inode *inode, struct file *filp);
365 : int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
366 : struct dentry *dentry);
367 : int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry,
368 : struct inode *new_dir, struct dentry *new_dentry,
369 : unsigned int flags);
370 : int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
371 : struct fscrypt_name *fname);
372 : int fscrypt_prepare_lookup_partial(struct inode *dir, struct dentry *dentry);
373 : int __fscrypt_prepare_readdir(struct inode *dir);
374 : int __fscrypt_prepare_setattr(struct dentry *dentry, struct iattr *attr);
375 : int fscrypt_prepare_setflags(struct inode *inode,
376 : unsigned int oldflags, unsigned int flags);
377 : int fscrypt_prepare_symlink(struct inode *dir, const char *target,
378 : unsigned int len, unsigned int max_len,
379 : struct fscrypt_str *disk_link);
380 : int __fscrypt_encrypt_symlink(struct inode *inode, const char *target,
381 : unsigned int len, struct fscrypt_str *disk_link);
382 : const char *fscrypt_get_symlink(struct inode *inode, const void *caddr,
383 : unsigned int max_size,
384 : struct delayed_call *done);
385 : int fscrypt_symlink_getattr(const struct path *path, struct kstat *stat);
386 : static inline void fscrypt_set_ops(struct super_block *sb,
387 : const struct fscrypt_operations *s_cop)
388 : {
389 : sb->s_cop = s_cop;
390 : }
391 : #else /* !CONFIG_FS_ENCRYPTION */
392 :
393 : static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode)
394 : {
395 : return NULL;
396 : }
397 :
398 : static inline bool fscrypt_needs_contents_encryption(const struct inode *inode)
399 : {
400 : return false;
401 : }
402 :
403 : static inline void fscrypt_handle_d_move(struct dentry *dentry)
404 : {
405 : }
406 :
407 : static inline bool fscrypt_is_nokey_name(const struct dentry *dentry)
408 : {
409 : return false;
410 : }
411 :
412 : /* crypto.c */
413 : static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work)
414 : {
415 : }
416 :
417 : static inline struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
418 : unsigned int len,
419 : unsigned int offs,
420 : gfp_t gfp_flags)
421 : {
422 : return ERR_PTR(-EOPNOTSUPP);
423 : }
424 :
425 : static inline int fscrypt_encrypt_block_inplace(const struct inode *inode,
426 : struct page *page,
427 : unsigned int len,
428 : unsigned int offs, u64 lblk_num,
429 : gfp_t gfp_flags)
430 : {
431 : return -EOPNOTSUPP;
432 : }
433 :
434 : static inline int fscrypt_decrypt_pagecache_blocks(struct folio *folio,
435 : size_t len, size_t offs)
436 : {
437 : return -EOPNOTSUPP;
438 : }
439 :
440 : static inline int fscrypt_decrypt_block_inplace(const struct inode *inode,
441 : struct page *page,
442 : unsigned int len,
443 : unsigned int offs, u64 lblk_num)
444 : {
445 : return -EOPNOTSUPP;
446 : }
447 :
448 : static inline bool fscrypt_is_bounce_page(struct page *page)
449 : {
450 : return false;
451 : }
452 :
453 : static inline struct page *fscrypt_pagecache_page(struct page *bounce_page)
454 : {
455 : WARN_ON_ONCE(1);
456 : return ERR_PTR(-EINVAL);
457 : }
458 :
459 : static inline bool fscrypt_is_bounce_folio(struct folio *folio)
460 : {
461 : return false;
462 : }
463 :
464 : static inline struct folio *fscrypt_pagecache_folio(struct folio *bounce_folio)
465 : {
466 : WARN_ON_ONCE(1);
467 : return ERR_PTR(-EINVAL);
468 : }
469 :
470 : static inline void fscrypt_free_bounce_page(struct page *bounce_page)
471 : {
472 : }
473 :
474 : /* policy.c */
475 : static inline int fscrypt_ioctl_set_policy(struct file *filp,
476 : const void __user *arg)
477 : {
478 : return -EOPNOTSUPP;
479 : }
480 :
481 : static inline int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
482 : {
483 : return -EOPNOTSUPP;
484 : }
485 :
486 : static inline int fscrypt_ioctl_get_policy_ex(struct file *filp,
487 : void __user *arg)
488 : {
489 : return -EOPNOTSUPP;
490 : }
491 :
492 : static inline int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg)
493 : {
494 : return -EOPNOTSUPP;
495 : }
496 :
497 : static inline int fscrypt_has_permitted_context(struct inode *parent,
498 : struct inode *child)
499 : {
500 : return 0;
501 : }
502 :
503 : static inline int fscrypt_set_context(struct inode *inode, void *fs_data)
504 : {
505 : return -EOPNOTSUPP;
506 : }
507 :
508 : struct fscrypt_dummy_policy {
509 : };
510 :
511 : static inline int
512 : fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param,
513 : struct fscrypt_dummy_policy *dummy_policy)
514 : {
515 : return -EINVAL;
516 : }
517 :
518 : static inline bool
519 : fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1,
520 : const struct fscrypt_dummy_policy *p2)
521 : {
522 : return true;
523 : }
524 :
525 : static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq,
526 : char sep,
527 : struct super_block *sb)
528 : {
529 : }
530 :
531 : static inline bool
532 : fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy)
533 : {
534 : return false;
535 : }
536 :
537 : static inline void
538 : fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy)
539 : {
540 : }
541 :
542 : /* keyring.c */
543 : static inline void fscrypt_destroy_keyring(struct super_block *sb)
544 : {
545 : }
546 :
547 : static inline int fscrypt_ioctl_add_key(struct file *filp, void __user *arg)
548 : {
549 : return -EOPNOTSUPP;
550 : }
551 :
552 : static inline int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg)
553 : {
554 : return -EOPNOTSUPP;
555 : }
556 :
557 : static inline int fscrypt_ioctl_remove_key_all_users(struct file *filp,
558 : void __user *arg)
559 : {
560 : return -EOPNOTSUPP;
561 : }
562 :
563 : static inline int fscrypt_ioctl_get_key_status(struct file *filp,
564 : void __user *arg)
565 : {
566 : return -EOPNOTSUPP;
567 : }
568 :
569 : /* keysetup.c */
570 :
571 : static inline int fscrypt_prepare_new_inode(struct inode *dir,
572 : struct inode *inode,
573 : bool *encrypt_ret)
574 : {
575 : if (IS_ENCRYPTED(dir))
576 : return -EOPNOTSUPP;
577 : return 0;
578 : }
579 :
580 : static inline void fscrypt_put_encryption_info(struct inode *inode)
581 : {
582 : return;
583 : }
584 :
585 : static inline void fscrypt_free_inode(struct inode *inode)
586 : {
587 : }
588 :
589 : static inline int fscrypt_drop_inode(struct inode *inode)
590 : {
591 : return 0;
592 : }
593 :
594 : /* fname.c */
595 : static inline int fscrypt_setup_filename(struct inode *dir,
596 : const struct qstr *iname,
597 : int lookup, struct fscrypt_name *fname)
598 : {
599 : if (IS_ENCRYPTED(dir))
600 : return -EOPNOTSUPP;
601 :
602 : memset(fname, 0, sizeof(*fname));
603 : fname->usr_fname = iname;
604 : fname->disk_name.name = (unsigned char *)iname->name;
605 : fname->disk_name.len = iname->len;
606 : return 0;
607 : }
608 :
609 : static inline void fscrypt_free_filename(struct fscrypt_name *fname)
610 : {
611 : return;
612 : }
613 :
614 : static inline int fscrypt_fname_alloc_buffer(u32 max_encrypted_len,
615 : struct fscrypt_str *crypto_str)
616 : {
617 : return -EOPNOTSUPP;
618 : }
619 :
620 : static inline void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str)
621 : {
622 : return;
623 : }
624 :
625 : static inline int fscrypt_fname_disk_to_usr(const struct inode *inode,
626 : u32 hash, u32 minor_hash,
627 : const struct fscrypt_str *iname,
628 : struct fscrypt_str *oname)
629 : {
630 : return -EOPNOTSUPP;
631 : }
632 :
633 : static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
634 : const u8 *de_name, u32 de_name_len)
635 : {
636 : /* Encryption support disabled; use standard comparison */
637 : if (de_name_len != fname->disk_name.len)
638 : return false;
639 : return !memcmp(de_name, fname->disk_name.name, fname->disk_name.len);
640 : }
641 :
642 : static inline u64 fscrypt_fname_siphash(const struct inode *dir,
643 : const struct qstr *name)
644 : {
645 : WARN_ON_ONCE(1);
646 : return 0;
647 : }
648 :
649 : static inline int fscrypt_d_revalidate(struct dentry *dentry,
650 : unsigned int flags)
651 : {
652 : return 1;
653 : }
654 :
655 : /* bio.c */
656 : static inline bool fscrypt_decrypt_bio(struct bio *bio)
657 : {
658 : return true;
659 : }
660 :
661 : static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
662 : sector_t pblk, unsigned int len)
663 : {
664 : return -EOPNOTSUPP;
665 : }
666 :
667 : /* hooks.c */
668 :
669 : static inline int fscrypt_file_open(struct inode *inode, struct file *filp)
670 : {
671 : if (IS_ENCRYPTED(inode))
672 : return -EOPNOTSUPP;
673 : return 0;
674 : }
675 :
676 : static inline int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
677 : struct dentry *dentry)
678 : {
679 : return -EOPNOTSUPP;
680 : }
681 :
682 : static inline int __fscrypt_prepare_rename(struct inode *old_dir,
683 : struct dentry *old_dentry,
684 : struct inode *new_dir,
685 : struct dentry *new_dentry,
686 : unsigned int flags)
687 : {
688 : return -EOPNOTSUPP;
689 : }
690 :
691 : static inline int __fscrypt_prepare_lookup(struct inode *dir,
692 : struct dentry *dentry,
693 : struct fscrypt_name *fname)
694 : {
695 : return -EOPNOTSUPP;
696 : }
697 :
698 : static inline int fscrypt_prepare_lookup_partial(struct inode *dir,
699 : struct dentry *dentry)
700 : {
701 : return -EOPNOTSUPP;
702 : }
703 :
704 : static inline int __fscrypt_prepare_readdir(struct inode *dir)
705 : {
706 : return -EOPNOTSUPP;
707 : }
708 :
709 : static inline int __fscrypt_prepare_setattr(struct dentry *dentry,
710 : struct iattr *attr)
711 : {
712 : return -EOPNOTSUPP;
713 : }
714 :
715 : static inline int fscrypt_prepare_setflags(struct inode *inode,
716 : unsigned int oldflags,
717 : unsigned int flags)
718 : {
719 : return 0;
720 : }
721 :
722 : static inline int fscrypt_prepare_symlink(struct inode *dir,
723 : const char *target,
724 : unsigned int len,
725 : unsigned int max_len,
726 : struct fscrypt_str *disk_link)
727 : {
728 : if (IS_ENCRYPTED(dir))
729 : return -EOPNOTSUPP;
730 : disk_link->name = (unsigned char *)target;
731 : disk_link->len = len + 1;
732 : if (disk_link->len > max_len)
733 : return -ENAMETOOLONG;
734 : return 0;
735 : }
736 :
737 : static inline int __fscrypt_encrypt_symlink(struct inode *inode,
738 : const char *target,
739 : unsigned int len,
740 : struct fscrypt_str *disk_link)
741 : {
742 : return -EOPNOTSUPP;
743 : }
744 :
745 : static inline const char *fscrypt_get_symlink(struct inode *inode,
746 : const void *caddr,
747 : unsigned int max_size,
748 : struct delayed_call *done)
749 : {
750 : return ERR_PTR(-EOPNOTSUPP);
751 : }
752 :
753 : static inline int fscrypt_symlink_getattr(const struct path *path,
754 : struct kstat *stat)
755 : {
756 : return -EOPNOTSUPP;
757 : }
758 :
759 : static inline void fscrypt_set_ops(struct super_block *sb,
760 : const struct fscrypt_operations *s_cop)
761 : {
762 : }
763 :
764 : #endif /* !CONFIG_FS_ENCRYPTION */
765 :
766 : /* inline_crypt.c */
767 : #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
768 :
769 : bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode);
770 :
771 : void fscrypt_set_bio_crypt_ctx(struct bio *bio,
772 : const struct inode *inode, u64 first_lblk,
773 : gfp_t gfp_mask);
774 :
775 : void fscrypt_set_bio_crypt_ctx_bh(struct bio *bio,
776 : const struct buffer_head *first_bh,
777 : gfp_t gfp_mask);
778 :
779 : bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode,
780 : u64 next_lblk);
781 :
782 : bool fscrypt_mergeable_bio_bh(struct bio *bio,
783 : const struct buffer_head *next_bh);
784 :
785 : bool fscrypt_dio_supported(struct inode *inode);
786 :
787 : u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, u64 nr_blocks);
788 :
789 : #else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
790 :
791 : static inline bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode)
792 : {
793 : return false;
794 : }
795 :
796 : static inline void fscrypt_set_bio_crypt_ctx(struct bio *bio,
797 : const struct inode *inode,
798 : u64 first_lblk, gfp_t gfp_mask) { }
799 :
800 : static inline void fscrypt_set_bio_crypt_ctx_bh(
801 : struct bio *bio,
802 : const struct buffer_head *first_bh,
803 : gfp_t gfp_mask) { }
804 :
805 : static inline bool fscrypt_mergeable_bio(struct bio *bio,
806 : const struct inode *inode,
807 : u64 next_lblk)
808 : {
809 : return true;
810 : }
811 :
812 : static inline bool fscrypt_mergeable_bio_bh(struct bio *bio,
813 : const struct buffer_head *next_bh)
814 : {
815 : return true;
816 : }
817 :
818 : static inline bool fscrypt_dio_supported(struct inode *inode)
819 : {
820 : return !fscrypt_needs_contents_encryption(inode);
821 : }
822 :
823 : static inline u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk,
824 : u64 nr_blocks)
825 : {
826 : return nr_blocks;
827 : }
828 : #endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
829 :
830 : /**
831 : * fscrypt_inode_uses_inline_crypto() - test whether an inode uses inline
832 : * encryption
833 : * @inode: an inode. If encrypted, its key must be set up.
834 : *
835 : * Return: true if the inode requires file contents encryption and if the
836 : * encryption should be done in the block layer via blk-crypto rather
837 : * than in the filesystem layer.
838 : */
839 : static inline bool fscrypt_inode_uses_inline_crypto(const struct inode *inode)
840 : {
841 : return fscrypt_needs_contents_encryption(inode) &&
842 : __fscrypt_inode_uses_inline_crypto(inode);
843 : }
844 :
845 : /**
846 : * fscrypt_inode_uses_fs_layer_crypto() - test whether an inode uses fs-layer
847 : * encryption
848 : * @inode: an inode. If encrypted, its key must be set up.
849 : *
850 : * Return: true if the inode requires file contents encryption and if the
851 : * encryption should be done in the filesystem layer rather than in the
852 : * block layer via blk-crypto.
853 : */
854 : static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode)
855 : {
856 0 : return fscrypt_needs_contents_encryption(inode) &&
857 : !__fscrypt_inode_uses_inline_crypto(inode);
858 : }
859 :
860 : /**
861 : * fscrypt_has_encryption_key() - check whether an inode has had its key set up
862 : * @inode: the inode to check
863 : *
864 : * Return: %true if the inode has had its encryption key set up, else %false.
865 : *
866 : * Usually this should be preceded by fscrypt_get_encryption_info() to try to
867 : * set up the key first.
868 : */
869 : static inline bool fscrypt_has_encryption_key(const struct inode *inode)
870 : {
871 : return fscrypt_get_info(inode) != NULL;
872 : }
873 :
874 : /**
875 : * fscrypt_prepare_link() - prepare to link an inode into a possibly-encrypted
876 : * directory
877 : * @old_dentry: an existing dentry for the inode being linked
878 : * @dir: the target directory
879 : * @dentry: negative dentry for the target filename
880 : *
881 : * A new link can only be added to an encrypted directory if the directory's
882 : * encryption key is available --- since otherwise we'd have no way to encrypt
883 : * the filename.
884 : *
885 : * We also verify that the link will not violate the constraint that all files
886 : * in an encrypted directory tree use the same encryption policy.
887 : *
888 : * Return: 0 on success, -ENOKEY if the directory's encryption key is missing,
889 : * -EXDEV if the link would result in an inconsistent encryption policy, or
890 : * another -errno code.
891 : */
892 : static inline int fscrypt_prepare_link(struct dentry *old_dentry,
893 : struct inode *dir,
894 : struct dentry *dentry)
895 : {
896 : if (IS_ENCRYPTED(dir))
897 : return __fscrypt_prepare_link(d_inode(old_dentry), dir, dentry);
898 : return 0;
899 : }
900 :
901 : /**
902 : * fscrypt_prepare_rename() - prepare for a rename between possibly-encrypted
903 : * directories
904 : * @old_dir: source directory
905 : * @old_dentry: dentry for source file
906 : * @new_dir: target directory
907 : * @new_dentry: dentry for target location (may be negative unless exchanging)
908 : * @flags: rename flags (we care at least about %RENAME_EXCHANGE)
909 : *
910 : * Prepare for ->rename() where the source and/or target directories may be
911 : * encrypted. A new link can only be added to an encrypted directory if the
912 : * directory's encryption key is available --- since otherwise we'd have no way
913 : * to encrypt the filename. A rename to an existing name, on the other hand,
914 : * *is* cryptographically possible without the key. However, we take the more
915 : * conservative approach and just forbid all no-key renames.
916 : *
917 : * We also verify that the rename will not violate the constraint that all files
918 : * in an encrypted directory tree use the same encryption policy.
919 : *
920 : * Return: 0 on success, -ENOKEY if an encryption key is missing, -EXDEV if the
921 : * rename would cause inconsistent encryption policies, or another -errno code.
922 : */
923 : static inline int fscrypt_prepare_rename(struct inode *old_dir,
924 : struct dentry *old_dentry,
925 : struct inode *new_dir,
926 : struct dentry *new_dentry,
927 : unsigned int flags)
928 : {
929 : if (IS_ENCRYPTED(old_dir) || IS_ENCRYPTED(new_dir))
930 : return __fscrypt_prepare_rename(old_dir, old_dentry,
931 : new_dir, new_dentry, flags);
932 : return 0;
933 : }
934 :
935 : /**
936 : * fscrypt_prepare_lookup() - prepare to lookup a name in a possibly-encrypted
937 : * directory
938 : * @dir: directory being searched
939 : * @dentry: filename being looked up
940 : * @fname: (output) the name to use to search the on-disk directory
941 : *
942 : * Prepare for ->lookup() in a directory which may be encrypted by determining
943 : * the name that will actually be used to search the directory on-disk. If the
944 : * directory's encryption policy is supported by this kernel and its encryption
945 : * key is available, then the lookup is assumed to be by plaintext name;
946 : * otherwise, it is assumed to be by no-key name.
947 : *
948 : * This will set DCACHE_NOKEY_NAME on the dentry if the lookup is by no-key
949 : * name. In this case the filesystem must assign the dentry a dentry_operations
950 : * which contains fscrypt_d_revalidate (or contains a d_revalidate method that
951 : * calls fscrypt_d_revalidate), so that the dentry will be invalidated if the
952 : * directory's encryption key is later added.
953 : *
954 : * Return: 0 on success; -ENOENT if the directory's key is unavailable but the
955 : * filename isn't a valid no-key name, so a negative dentry should be created;
956 : * or another -errno code.
957 : */
958 : static inline int fscrypt_prepare_lookup(struct inode *dir,
959 : struct dentry *dentry,
960 : struct fscrypt_name *fname)
961 : {
962 : if (IS_ENCRYPTED(dir))
963 : return __fscrypt_prepare_lookup(dir, dentry, fname);
964 :
965 : memset(fname, 0, sizeof(*fname));
966 : fname->usr_fname = &dentry->d_name;
967 : fname->disk_name.name = (unsigned char *)dentry->d_name.name;
968 : fname->disk_name.len = dentry->d_name.len;
969 : return 0;
970 : }
971 :
972 : /**
973 : * fscrypt_prepare_readdir() - prepare to read a possibly-encrypted directory
974 : * @dir: the directory inode
975 : *
976 : * If the directory is encrypted and it doesn't already have its encryption key
977 : * set up, try to set it up so that the filenames will be listed in plaintext
978 : * form rather than in no-key form.
979 : *
980 : * Return: 0 on success; -errno on error. Note that the encryption key being
981 : * unavailable is not considered an error. It is also not an error if
982 : * the encryption policy is unsupported by this kernel; that is treated
983 : * like the key being unavailable, so that files can still be deleted.
984 : */
985 : static inline int fscrypt_prepare_readdir(struct inode *dir)
986 : {
987 : if (IS_ENCRYPTED(dir))
988 : return __fscrypt_prepare_readdir(dir);
989 : return 0;
990 : }
991 :
992 : /**
993 : * fscrypt_prepare_setattr() - prepare to change a possibly-encrypted inode's
994 : * attributes
995 : * @dentry: dentry through which the inode is being changed
996 : * @attr: attributes to change
997 : *
998 : * Prepare for ->setattr() on a possibly-encrypted inode. On an encrypted file,
999 : * most attribute changes are allowed even without the encryption key. However,
1000 : * without the encryption key we do have to forbid truncates. This is needed
1001 : * because the size being truncated to may not be a multiple of the filesystem
1002 : * block size, and in that case we'd have to decrypt the final block, zero the
1003 : * portion past i_size, and re-encrypt it. (We *could* allow truncating to a
1004 : * filesystem block boundary, but it's simpler to just forbid all truncates ---
1005 : * and we already forbid all other contents modifications without the key.)
1006 : *
1007 : * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
1008 : * if a problem occurred while setting up the encryption key.
1009 : */
1010 : static inline int fscrypt_prepare_setattr(struct dentry *dentry,
1011 : struct iattr *attr)
1012 : {
1013 : if (IS_ENCRYPTED(d_inode(dentry)))
1014 : return __fscrypt_prepare_setattr(dentry, attr);
1015 : return 0;
1016 : }
1017 :
1018 : /**
1019 : * fscrypt_encrypt_symlink() - encrypt the symlink target if needed
1020 : * @inode: symlink inode
1021 : * @target: plaintext symlink target
1022 : * @len: length of @target excluding null terminator
1023 : * @disk_link: (in/out) the on-disk symlink target being prepared
1024 : *
1025 : * If the symlink target needs to be encrypted, then this function encrypts it
1026 : * into @disk_link->name. fscrypt_prepare_symlink() must have been called
1027 : * previously to compute @disk_link->len. If the filesystem did not allocate a
1028 : * buffer for @disk_link->name after calling fscrypt_prepare_link(), then one
1029 : * will be kmalloc()'ed and the filesystem will be responsible for freeing it.
1030 : *
1031 : * Return: 0 on success, -errno on failure
1032 : */
1033 : static inline int fscrypt_encrypt_symlink(struct inode *inode,
1034 : const char *target,
1035 : unsigned int len,
1036 : struct fscrypt_str *disk_link)
1037 : {
1038 : if (IS_ENCRYPTED(inode))
1039 : return __fscrypt_encrypt_symlink(inode, target, len, disk_link);
1040 : return 0;
1041 : }
1042 :
1043 : /* If *pagep is a bounce page, free it and set *pagep to the pagecache page */
1044 : static inline void fscrypt_finalize_bounce_page(struct page **pagep)
1045 : {
1046 : struct page *page = *pagep;
1047 :
1048 : if (fscrypt_is_bounce_page(page)) {
1049 : *pagep = fscrypt_pagecache_page(page);
1050 : fscrypt_free_bounce_page(page);
1051 : }
1052 : }
1053 :
1054 : #endif /* _LINUX_FSCRYPT_H */
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