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
33union fscrypt_policy;
34struct fscrypt_inode_info;
35struct fs_parameter;
36struct seq_file;
37
38struct fscrypt_str {
39 unsigned char *name;
40 u32 len;
41};
42
43struct 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/* Crypto operations for filesystems */
63struct fscrypt_operations {
64
65 /*
66 * If set, then fs/crypto/ will allocate a global bounce page pool the
67 * first time an encryption key is set up for a file. The bounce page
68 * pool is required by the following functions:
69 *
70 * - fscrypt_encrypt_pagecache_blocks()
71 * - fscrypt_zeroout_range() for files not using inline crypto
72 *
73 * If the filesystem doesn't use those, it doesn't need to set this.
74 */
75 unsigned int needs_bounce_pages : 1;
76
77 /*
78 * If set, then fs/crypto/ will allow the use of encryption settings
79 * that assume inode numbers fit in 32 bits (i.e.
80 * FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64}), provided that the other
81 * prerequisites for these settings are also met. This is only useful
82 * if the filesystem wants to support inline encryption hardware that is
83 * limited to 32-bit or 64-bit data unit numbers and where programming
84 * keyslots is very slow.
85 */
86 unsigned int has_32bit_inodes : 1;
87
88 /*
89 * If set, then fs/crypto/ will allow users to select a crypto data unit
90 * size that is less than the filesystem block size. This is done via
91 * the log2_data_unit_size field of the fscrypt policy. This flag is
92 * not compatible with filesystems that encrypt variable-length blocks
93 * (i.e. blocks that aren't all equal to filesystem's block size), for
94 * example as a result of compression. It's also not compatible with
95 * the fscrypt_encrypt_block_inplace() and
96 * fscrypt_decrypt_block_inplace() functions.
97 */
98 unsigned int supports_subblock_data_units : 1;
99
100 /*
101 * This field exists only for backwards compatibility reasons and should
102 * only be set by the filesystems that are setting it already. It
103 * contains the filesystem-specific key description prefix that is
104 * accepted for "logon" keys for v1 fscrypt policies. This
105 * functionality is deprecated in favor of the generic prefix
106 * "fscrypt:", which itself is deprecated in favor of the filesystem
107 * keyring ioctls such as FS_IOC_ADD_ENCRYPTION_KEY. Filesystems that
108 * are newly adding fscrypt support should not set this field.
109 */
110 const char *legacy_key_prefix;
111
112 /*
113 * Get the fscrypt context of the given inode.
114 *
115 * @inode: the inode whose context to get
116 * @ctx: the buffer into which to get the context
117 * @len: length of the @ctx buffer in bytes
118 *
119 * Return: On success, returns the length of the context in bytes; this
120 * may be less than @len. On failure, returns -ENODATA if the
121 * inode doesn't have a context, -ERANGE if the context is
122 * longer than @len, or another -errno code.
123 */
124 int (*get_context)(struct inode *inode, void *ctx, size_t len);
125
126 /*
127 * Set an fscrypt context on the given inode.
128 *
129 * @inode: the inode whose context to set. The inode won't already have
130 * an fscrypt context.
131 * @ctx: the context to set
132 * @len: length of @ctx in bytes (at most FSCRYPT_SET_CONTEXT_MAX_SIZE)
133 * @fs_data: If called from fscrypt_set_context(), this will be the
134 * value the filesystem passed to fscrypt_set_context().
135 * Otherwise (i.e. when called from
136 * FS_IOC_SET_ENCRYPTION_POLICY) this will be NULL.
137 *
138 * i_rwsem will be held for write.
139 *
140 * Return: 0 on success, -errno on failure.
141 */
142 int (*set_context)(struct inode *inode, const void *ctx, size_t len,
143 void *fs_data);
144
145 /*
146 * Get the dummy fscrypt policy in use on the filesystem (if any).
147 *
148 * Filesystems only need to implement this function if they support the
149 * test_dummy_encryption mount option.
150 *
151 * Return: A pointer to the dummy fscrypt policy, if the filesystem is
152 * mounted with test_dummy_encryption; otherwise NULL.
153 */
154 const union fscrypt_policy *(*get_dummy_policy)(struct super_block *sb);
155
156 /*
157 * Check whether a directory is empty. i_rwsem will be held for write.
158 */
159 bool (*empty_dir)(struct inode *inode);
160
161 /*
162 * Check whether the filesystem's inode numbers and UUID are stable,
163 * meaning that they will never be changed even by offline operations
164 * such as filesystem shrinking and therefore can be used in the
165 * encryption without the possibility of files becoming unreadable.
166 *
167 * Filesystems only need to implement this function if they want to
168 * support the FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64} flags. These
169 * flags are designed to work around the limitations of UFS and eMMC
170 * inline crypto hardware, and they shouldn't be used in scenarios where
171 * such hardware isn't being used.
172 *
173 * Leaving this NULL is equivalent to always returning false.
174 */
175 bool (*has_stable_inodes)(struct super_block *sb);
176
177 /*
178 * Return an array of pointers to the block devices to which the
179 * filesystem may write encrypted file contents, NULL if the filesystem
180 * only has a single such block device, or an ERR_PTR() on error.
181 *
182 * On successful non-NULL return, *num_devs is set to the number of
183 * devices in the returned array. The caller must free the returned
184 * array using kfree().
185 *
186 * If the filesystem can use multiple block devices (other than block
187 * devices that aren't used for encrypted file contents, such as
188 * external journal devices), and wants to support inline encryption,
189 * then it must implement this function. Otherwise it's not needed.
190 */
191 struct block_device **(*get_devices)(struct super_block *sb,
192 unsigned int *num_devs);
193};
194
195int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name,
196 struct dentry *dentry, unsigned int flags);
197
198static inline struct fscrypt_inode_info *
199fscrypt_get_inode_info(const struct inode *inode)
200{
201 /*
202 * Pairs with the cmpxchg_release() in fscrypt_setup_encryption_info().
203 * I.e., another task may publish ->i_crypt_info concurrently, executing
204 * a RELEASE barrier. We need to use smp_load_acquire() here to safely
205 * ACQUIRE the memory the other task published.
206 */
207 return smp_load_acquire(&inode->i_crypt_info);
208}
209
210/**
211 * fscrypt_needs_contents_encryption() - check whether an inode needs
212 * contents encryption
213 * @inode: the inode to check
214 *
215 * Return: %true iff the inode is an encrypted regular file and the kernel was
216 * built with fscrypt support.
217 *
218 * If you need to know whether the encrypt bit is set even when the kernel was
219 * built without fscrypt support, you must use IS_ENCRYPTED() directly instead.
220 */
221static inline bool fscrypt_needs_contents_encryption(const struct inode *inode)
222{
223 return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode);
224}
225
226/*
227 * When d_splice_alias() moves a directory's no-key alias to its
228 * plaintext alias as a result of the encryption key being added,
229 * DCACHE_NOKEY_NAME must be cleared and there might be an opportunity
230 * to disable d_revalidate. Note that we don't have to support the
231 * inverse operation because fscrypt doesn't allow no-key names to be
232 * the source or target of a rename().
233 */
234static inline void fscrypt_handle_d_move(struct dentry *dentry)
235{
236 /*
237 * VFS calls fscrypt_handle_d_move even for non-fscrypt
238 * filesystems.
239 */
240 if (dentry->d_flags & DCACHE_NOKEY_NAME) {
241 dentry->d_flags &= ~DCACHE_NOKEY_NAME;
242
243 /*
244 * Other filesystem features might be handling dentry
245 * revalidation, in which case it cannot be disabled.
246 */
247 if (dentry->d_op->d_revalidate == fscrypt_d_revalidate)
248 dentry->d_flags &= ~DCACHE_OP_REVALIDATE;
249 }
250}
251
252/**
253 * fscrypt_is_nokey_name() - test whether a dentry is a no-key name
254 * @dentry: the dentry to check
255 *
256 * This returns true if the dentry is a no-key dentry. A no-key dentry is a
257 * dentry that was created in an encrypted directory that hasn't had its
258 * encryption key added yet. Such dentries may be either positive or negative.
259 *
260 * When a filesystem is asked to create a new filename in an encrypted directory
261 * and the new filename's dentry is a no-key dentry, it must fail the operation
262 * with ENOKEY. This includes ->create(), ->mkdir(), ->mknod(), ->symlink(),
263 * ->rename(), and ->link(). (However, ->rename() and ->link() are already
264 * handled by fscrypt_prepare_rename() and fscrypt_prepare_link().)
265 *
266 * This is necessary because creating a filename requires the directory's
267 * encryption key, but just checking for the key on the directory inode during
268 * the final filesystem operation doesn't guarantee that the key was available
269 * during the preceding dentry lookup. And the key must have already been
270 * available during the dentry lookup in order for it to have been checked
271 * whether the filename already exists in the directory and for the new file's
272 * dentry not to be invalidated due to it incorrectly having the no-key flag.
273 *
274 * Return: %true if the dentry is a no-key name
275 */
276static inline bool fscrypt_is_nokey_name(const struct dentry *dentry)
277{
278 return dentry->d_flags & DCACHE_NOKEY_NAME;
279}
280
281static inline void fscrypt_prepare_dentry(struct dentry *dentry,
282 bool is_nokey_name)
283{
284 /*
285 * This code tries to only take ->d_lock when necessary to write
286 * to ->d_flags. We shouldn't be peeking on d_flags for
287 * DCACHE_OP_REVALIDATE unlocked, but in the unlikely case
288 * there is a race, the worst it can happen is that we fail to
289 * unset DCACHE_OP_REVALIDATE and pay the cost of an extra
290 * d_revalidate.
291 */
292 if (is_nokey_name) {
293 spin_lock(lock: &dentry->d_lock);
294 dentry->d_flags |= DCACHE_NOKEY_NAME;
295 spin_unlock(lock: &dentry->d_lock);
296 } else if (dentry->d_flags & DCACHE_OP_REVALIDATE &&
297 dentry->d_op->d_revalidate == fscrypt_d_revalidate) {
298 /*
299 * Unencrypted dentries and encrypted dentries where the
300 * key is available are always valid from fscrypt
301 * perspective. Avoid the cost of calling
302 * fscrypt_d_revalidate unnecessarily.
303 */
304 spin_lock(lock: &dentry->d_lock);
305 dentry->d_flags &= ~DCACHE_OP_REVALIDATE;
306 spin_unlock(lock: &dentry->d_lock);
307 }
308}
309
310/* crypto.c */
311void fscrypt_enqueue_decrypt_work(struct work_struct *);
312
313struct page *fscrypt_encrypt_pagecache_blocks(struct folio *folio,
314 size_t len, size_t offs, gfp_t gfp_flags);
315int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page,
316 unsigned int len, unsigned int offs,
317 u64 lblk_num, gfp_t gfp_flags);
318
319int fscrypt_decrypt_pagecache_blocks(struct folio *folio, size_t len,
320 size_t offs);
321int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page,
322 unsigned int len, unsigned int offs,
323 u64 lblk_num);
324
325static inline bool fscrypt_is_bounce_page(struct page *page)
326{
327 return page->mapping == NULL;
328}
329
330static inline struct page *fscrypt_pagecache_page(struct page *bounce_page)
331{
332 return (struct page *)page_private(bounce_page);
333}
334
335static inline bool fscrypt_is_bounce_folio(struct folio *folio)
336{
337 return folio->mapping == NULL;
338}
339
340static inline struct folio *fscrypt_pagecache_folio(struct folio *bounce_folio)
341{
342 return bounce_folio->private;
343}
344
345void fscrypt_free_bounce_page(struct page *bounce_page);
346
347/* policy.c */
348int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg);
349int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg);
350int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *arg);
351int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg);
352int fscrypt_has_permitted_context(struct inode *parent, struct inode *child);
353int fscrypt_context_for_new_inode(void *ctx, struct inode *inode);
354int fscrypt_set_context(struct inode *inode, void *fs_data);
355
356struct fscrypt_dummy_policy {
357 const union fscrypt_policy *policy;
358};
359
360int fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param,
361 struct fscrypt_dummy_policy *dummy_policy);
362bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1,
363 const struct fscrypt_dummy_policy *p2);
364void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep,
365 struct super_block *sb);
366static inline bool
367fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy)
368{
369 return dummy_policy->policy != NULL;
370}
371static inline void
372fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy)
373{
374 kfree(objp: dummy_policy->policy);
375 dummy_policy->policy = NULL;
376}
377
378/* keyring.c */
379void fscrypt_destroy_keyring(struct super_block *sb);
380int fscrypt_ioctl_add_key(struct file *filp, void __user *arg);
381int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg);
382int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *arg);
383int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg);
384
385/* keysetup.c */
386int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode,
387 bool *encrypt_ret);
388void fscrypt_put_encryption_info(struct inode *inode);
389void fscrypt_free_inode(struct inode *inode);
390int fscrypt_drop_inode(struct inode *inode);
391
392/* fname.c */
393int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
394 u8 *out, unsigned int olen);
395bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len,
396 u32 max_len, u32 *encrypted_len_ret);
397int fscrypt_setup_filename(struct inode *inode, const struct qstr *iname,
398 int lookup, struct fscrypt_name *fname);
399
400static inline void fscrypt_free_filename(struct fscrypt_name *fname)
401{
402 kfree(objp: fname->crypto_buf.name);
403}
404
405int fscrypt_fname_alloc_buffer(u32 max_encrypted_len,
406 struct fscrypt_str *crypto_str);
407void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str);
408int fscrypt_fname_disk_to_usr(const struct inode *inode,
409 u32 hash, u32 minor_hash,
410 const struct fscrypt_str *iname,
411 struct fscrypt_str *oname);
412bool fscrypt_match_name(const struct fscrypt_name *fname,
413 const u8 *de_name, u32 de_name_len);
414u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name);
415
416/* bio.c */
417bool fscrypt_decrypt_bio(struct bio *bio);
418int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
419 sector_t pblk, unsigned int len);
420
421/* hooks.c */
422int fscrypt_file_open(struct inode *inode, struct file *filp);
423int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
424 struct dentry *dentry);
425int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry,
426 struct inode *new_dir, struct dentry *new_dentry,
427 unsigned int flags);
428int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
429 struct fscrypt_name *fname);
430int fscrypt_prepare_lookup_partial(struct inode *dir, struct dentry *dentry);
431int __fscrypt_prepare_readdir(struct inode *dir);
432int __fscrypt_prepare_setattr(struct dentry *dentry, struct iattr *attr);
433int fscrypt_prepare_setflags(struct inode *inode,
434 unsigned int oldflags, unsigned int flags);
435int fscrypt_prepare_symlink(struct inode *dir, const char *target,
436 unsigned int len, unsigned int max_len,
437 struct fscrypt_str *disk_link);
438int __fscrypt_encrypt_symlink(struct inode *inode, const char *target,
439 unsigned int len, struct fscrypt_str *disk_link);
440const char *fscrypt_get_symlink(struct inode *inode, const void *caddr,
441 unsigned int max_size,
442 struct delayed_call *done);
443int fscrypt_symlink_getattr(const struct path *path, struct kstat *stat);
444static inline void fscrypt_set_ops(struct super_block *sb,
445 const struct fscrypt_operations *s_cop)
446{
447 sb->s_cop = s_cop;
448}
449#else /* !CONFIG_FS_ENCRYPTION */
450
451static inline struct fscrypt_inode_info *
452fscrypt_get_inode_info(const struct inode *inode)
453{
454 return NULL;
455}
456
457static inline bool fscrypt_needs_contents_encryption(const struct inode *inode)
458{
459 return false;
460}
461
462static inline void fscrypt_handle_d_move(struct dentry *dentry)
463{
464}
465
466static inline bool fscrypt_is_nokey_name(const struct dentry *dentry)
467{
468 return false;
469}
470
471static inline void fscrypt_prepare_dentry(struct dentry *dentry,
472 bool is_nokey_name)
473{
474}
475
476/* crypto.c */
477static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work)
478{
479}
480
481static inline struct page *fscrypt_encrypt_pagecache_blocks(struct folio *folio,
482 size_t len, size_t offs, gfp_t gfp_flags)
483{
484 return ERR_PTR(-EOPNOTSUPP);
485}
486
487static inline int fscrypt_encrypt_block_inplace(const struct inode *inode,
488 struct page *page,
489 unsigned int len,
490 unsigned int offs, u64 lblk_num,
491 gfp_t gfp_flags)
492{
493 return -EOPNOTSUPP;
494}
495
496static inline int fscrypt_decrypt_pagecache_blocks(struct folio *folio,
497 size_t len, size_t offs)
498{
499 return -EOPNOTSUPP;
500}
501
502static inline int fscrypt_decrypt_block_inplace(const struct inode *inode,
503 struct page *page,
504 unsigned int len,
505 unsigned int offs, u64 lblk_num)
506{
507 return -EOPNOTSUPP;
508}
509
510static inline bool fscrypt_is_bounce_page(struct page *page)
511{
512 return false;
513}
514
515static inline struct page *fscrypt_pagecache_page(struct page *bounce_page)
516{
517 WARN_ON_ONCE(1);
518 return ERR_PTR(-EINVAL);
519}
520
521static inline bool fscrypt_is_bounce_folio(struct folio *folio)
522{
523 return false;
524}
525
526static inline struct folio *fscrypt_pagecache_folio(struct folio *bounce_folio)
527{
528 WARN_ON_ONCE(1);
529 return ERR_PTR(-EINVAL);
530}
531
532static inline void fscrypt_free_bounce_page(struct page *bounce_page)
533{
534}
535
536/* policy.c */
537static inline int fscrypt_ioctl_set_policy(struct file *filp,
538 const void __user *arg)
539{
540 return -EOPNOTSUPP;
541}
542
543static inline int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
544{
545 return -EOPNOTSUPP;
546}
547
548static inline int fscrypt_ioctl_get_policy_ex(struct file *filp,
549 void __user *arg)
550{
551 return -EOPNOTSUPP;
552}
553
554static inline int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg)
555{
556 return -EOPNOTSUPP;
557}
558
559static inline int fscrypt_has_permitted_context(struct inode *parent,
560 struct inode *child)
561{
562 return 0;
563}
564
565static inline int fscrypt_set_context(struct inode *inode, void *fs_data)
566{
567 return -EOPNOTSUPP;
568}
569
570struct fscrypt_dummy_policy {
571};
572
573static inline int
574fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param,
575 struct fscrypt_dummy_policy *dummy_policy)
576{
577 return -EINVAL;
578}
579
580static inline bool
581fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1,
582 const struct fscrypt_dummy_policy *p2)
583{
584 return true;
585}
586
587static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq,
588 char sep,
589 struct super_block *sb)
590{
591}
592
593static inline bool
594fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy)
595{
596 return false;
597}
598
599static inline void
600fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy)
601{
602}
603
604/* keyring.c */
605static inline void fscrypt_destroy_keyring(struct super_block *sb)
606{
607}
608
609static inline int fscrypt_ioctl_add_key(struct file *filp, void __user *arg)
610{
611 return -EOPNOTSUPP;
612}
613
614static inline int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg)
615{
616 return -EOPNOTSUPP;
617}
618
619static inline int fscrypt_ioctl_remove_key_all_users(struct file *filp,
620 void __user *arg)
621{
622 return -EOPNOTSUPP;
623}
624
625static inline int fscrypt_ioctl_get_key_status(struct file *filp,
626 void __user *arg)
627{
628 return -EOPNOTSUPP;
629}
630
631/* keysetup.c */
632
633static inline int fscrypt_prepare_new_inode(struct inode *dir,
634 struct inode *inode,
635 bool *encrypt_ret)
636{
637 if (IS_ENCRYPTED(dir))
638 return -EOPNOTSUPP;
639 return 0;
640}
641
642static inline void fscrypt_put_encryption_info(struct inode *inode)
643{
644 return;
645}
646
647static inline void fscrypt_free_inode(struct inode *inode)
648{
649}
650
651static inline int fscrypt_drop_inode(struct inode *inode)
652{
653 return 0;
654}
655
656 /* fname.c */
657static inline int fscrypt_setup_filename(struct inode *dir,
658 const struct qstr *iname,
659 int lookup, struct fscrypt_name *fname)
660{
661 if (IS_ENCRYPTED(dir))
662 return -EOPNOTSUPP;
663
664 memset(fname, 0, sizeof(*fname));
665 fname->usr_fname = iname;
666 fname->disk_name.name = (unsigned char *)iname->name;
667 fname->disk_name.len = iname->len;
668 return 0;
669}
670
671static inline void fscrypt_free_filename(struct fscrypt_name *fname)
672{
673 return;
674}
675
676static inline int fscrypt_fname_alloc_buffer(u32 max_encrypted_len,
677 struct fscrypt_str *crypto_str)
678{
679 return -EOPNOTSUPP;
680}
681
682static inline void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str)
683{
684 return;
685}
686
687static inline int fscrypt_fname_disk_to_usr(const struct inode *inode,
688 u32 hash, u32 minor_hash,
689 const struct fscrypt_str *iname,
690 struct fscrypt_str *oname)
691{
692 return -EOPNOTSUPP;
693}
694
695static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
696 const u8 *de_name, u32 de_name_len)
697{
698 /* Encryption support disabled; use standard comparison */
699 if (de_name_len != fname->disk_name.len)
700 return false;
701 return !memcmp(de_name, fname->disk_name.name, fname->disk_name.len);
702}
703
704static inline u64 fscrypt_fname_siphash(const struct inode *dir,
705 const struct qstr *name)
706{
707 WARN_ON_ONCE(1);
708 return 0;
709}
710
711static inline int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name,
712 struct dentry *dentry, unsigned int flags)
713{
714 return 1;
715}
716
717/* bio.c */
718static inline bool fscrypt_decrypt_bio(struct bio *bio)
719{
720 return true;
721}
722
723static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
724 sector_t pblk, unsigned int len)
725{
726 return -EOPNOTSUPP;
727}
728
729/* hooks.c */
730
731static inline int fscrypt_file_open(struct inode *inode, struct file *filp)
732{
733 if (IS_ENCRYPTED(inode))
734 return -EOPNOTSUPP;
735 return 0;
736}
737
738static inline int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
739 struct dentry *dentry)
740{
741 return -EOPNOTSUPP;
742}
743
744static inline int __fscrypt_prepare_rename(struct inode *old_dir,
745 struct dentry *old_dentry,
746 struct inode *new_dir,
747 struct dentry *new_dentry,
748 unsigned int flags)
749{
750 return -EOPNOTSUPP;
751}
752
753static inline int __fscrypt_prepare_lookup(struct inode *dir,
754 struct dentry *dentry,
755 struct fscrypt_name *fname)
756{
757 return -EOPNOTSUPP;
758}
759
760static inline int fscrypt_prepare_lookup_partial(struct inode *dir,
761 struct dentry *dentry)
762{
763 return -EOPNOTSUPP;
764}
765
766static inline int __fscrypt_prepare_readdir(struct inode *dir)
767{
768 return -EOPNOTSUPP;
769}
770
771static inline int __fscrypt_prepare_setattr(struct dentry *dentry,
772 struct iattr *attr)
773{
774 return -EOPNOTSUPP;
775}
776
777static inline int fscrypt_prepare_setflags(struct inode *inode,
778 unsigned int oldflags,
779 unsigned int flags)
780{
781 return 0;
782}
783
784static inline int fscrypt_prepare_symlink(struct inode *dir,
785 const char *target,
786 unsigned int len,
787 unsigned int max_len,
788 struct fscrypt_str *disk_link)
789{
790 if (IS_ENCRYPTED(dir))
791 return -EOPNOTSUPP;
792 disk_link->name = (unsigned char *)target;
793 disk_link->len = len + 1;
794 if (disk_link->len > max_len)
795 return -ENAMETOOLONG;
796 return 0;
797}
798
799static inline int __fscrypt_encrypt_symlink(struct inode *inode,
800 const char *target,
801 unsigned int len,
802 struct fscrypt_str *disk_link)
803{
804 return -EOPNOTSUPP;
805}
806
807static inline const char *fscrypt_get_symlink(struct inode *inode,
808 const void *caddr,
809 unsigned int max_size,
810 struct delayed_call *done)
811{
812 return ERR_PTR(-EOPNOTSUPP);
813}
814
815static inline int fscrypt_symlink_getattr(const struct path *path,
816 struct kstat *stat)
817{
818 return -EOPNOTSUPP;
819}
820
821static inline void fscrypt_set_ops(struct super_block *sb,
822 const struct fscrypt_operations *s_cop)
823{
824}
825
826#endif /* !CONFIG_FS_ENCRYPTION */
827
828/* inline_crypt.c */
829#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
830
831bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode);
832
833void fscrypt_set_bio_crypt_ctx(struct bio *bio,
834 const struct inode *inode, u64 first_lblk,
835 gfp_t gfp_mask);
836
837void fscrypt_set_bio_crypt_ctx_bh(struct bio *bio,
838 const struct buffer_head *first_bh,
839 gfp_t gfp_mask);
840
841bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode,
842 u64 next_lblk);
843
844bool fscrypt_mergeable_bio_bh(struct bio *bio,
845 const struct buffer_head *next_bh);
846
847bool fscrypt_dio_supported(struct inode *inode);
848
849u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, u64 nr_blocks);
850
851#else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
852
853static inline bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode)
854{
855 return false;
856}
857
858static inline void fscrypt_set_bio_crypt_ctx(struct bio *bio,
859 const struct inode *inode,
860 u64 first_lblk, gfp_t gfp_mask) { }
861
862static inline void fscrypt_set_bio_crypt_ctx_bh(
863 struct bio *bio,
864 const struct buffer_head *first_bh,
865 gfp_t gfp_mask) { }
866
867static inline bool fscrypt_mergeable_bio(struct bio *bio,
868 const struct inode *inode,
869 u64 next_lblk)
870{
871 return true;
872}
873
874static inline bool fscrypt_mergeable_bio_bh(struct bio *bio,
875 const struct buffer_head *next_bh)
876{
877 return true;
878}
879
880static inline bool fscrypt_dio_supported(struct inode *inode)
881{
882 return !fscrypt_needs_contents_encryption(inode);
883}
884
885static inline u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk,
886 u64 nr_blocks)
887{
888 return nr_blocks;
889}
890#endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
891
892/**
893 * fscrypt_inode_uses_inline_crypto() - test whether an inode uses inline
894 * encryption
895 * @inode: an inode. If encrypted, its key must be set up.
896 *
897 * Return: true if the inode requires file contents encryption and if the
898 * encryption should be done in the block layer via blk-crypto rather
899 * than in the filesystem layer.
900 */
901static inline bool fscrypt_inode_uses_inline_crypto(const struct inode *inode)
902{
903 return fscrypt_needs_contents_encryption(inode) &&
904 __fscrypt_inode_uses_inline_crypto(inode);
905}
906
907/**
908 * fscrypt_inode_uses_fs_layer_crypto() - test whether an inode uses fs-layer
909 * encryption
910 * @inode: an inode. If encrypted, its key must be set up.
911 *
912 * Return: true if the inode requires file contents encryption and if the
913 * encryption should be done in the filesystem layer rather than in the
914 * block layer via blk-crypto.
915 */
916static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode)
917{
918 return fscrypt_needs_contents_encryption(inode) &&
919 !__fscrypt_inode_uses_inline_crypto(inode);
920}
921
922/**
923 * fscrypt_has_encryption_key() - check whether an inode has had its key set up
924 * @inode: the inode to check
925 *
926 * Return: %true if the inode has had its encryption key set up, else %false.
927 *
928 * Usually this should be preceded by fscrypt_get_encryption_info() to try to
929 * set up the key first.
930 */
931static inline bool fscrypt_has_encryption_key(const struct inode *inode)
932{
933 return fscrypt_get_inode_info(inode) != NULL;
934}
935
936/**
937 * fscrypt_prepare_link() - prepare to link an inode into a possibly-encrypted
938 * directory
939 * @old_dentry: an existing dentry for the inode being linked
940 * @dir: the target directory
941 * @dentry: negative dentry for the target filename
942 *
943 * A new link can only be added to an encrypted directory if the directory's
944 * encryption key is available --- since otherwise we'd have no way to encrypt
945 * the filename.
946 *
947 * We also verify that the link will not violate the constraint that all files
948 * in an encrypted directory tree use the same encryption policy.
949 *
950 * Return: 0 on success, -ENOKEY if the directory's encryption key is missing,
951 * -EXDEV if the link would result in an inconsistent encryption policy, or
952 * another -errno code.
953 */
954static inline int fscrypt_prepare_link(struct dentry *old_dentry,
955 struct inode *dir,
956 struct dentry *dentry)
957{
958 if (IS_ENCRYPTED(dir))
959 return __fscrypt_prepare_link(inode: d_inode(dentry: old_dentry), dir, dentry);
960 return 0;
961}
962
963/**
964 * fscrypt_prepare_rename() - prepare for a rename between possibly-encrypted
965 * directories
966 * @old_dir: source directory
967 * @old_dentry: dentry for source file
968 * @new_dir: target directory
969 * @new_dentry: dentry for target location (may be negative unless exchanging)
970 * @flags: rename flags (we care at least about %RENAME_EXCHANGE)
971 *
972 * Prepare for ->rename() where the source and/or target directories may be
973 * encrypted. A new link can only be added to an encrypted directory if the
974 * directory's encryption key is available --- since otherwise we'd have no way
975 * to encrypt the filename. A rename to an existing name, on the other hand,
976 * *is* cryptographically possible without the key. However, we take the more
977 * conservative approach and just forbid all no-key renames.
978 *
979 * We also verify that the rename will not violate the constraint that all files
980 * in an encrypted directory tree use the same encryption policy.
981 *
982 * Return: 0 on success, -ENOKEY if an encryption key is missing, -EXDEV if the
983 * rename would cause inconsistent encryption policies, or another -errno code.
984 */
985static inline int fscrypt_prepare_rename(struct inode *old_dir,
986 struct dentry *old_dentry,
987 struct inode *new_dir,
988 struct dentry *new_dentry,
989 unsigned int flags)
990{
991 if (IS_ENCRYPTED(old_dir) || IS_ENCRYPTED(new_dir))
992 return __fscrypt_prepare_rename(old_dir, old_dentry,
993 new_dir, new_dentry, flags);
994 return 0;
995}
996
997/**
998 * fscrypt_prepare_lookup() - prepare to lookup a name in a possibly-encrypted
999 * directory
1000 * @dir: directory being searched
1001 * @dentry: filename being looked up
1002 * @fname: (output) the name to use to search the on-disk directory
1003 *
1004 * Prepare for ->lookup() in a directory which may be encrypted by determining
1005 * the name that will actually be used to search the directory on-disk. If the
1006 * directory's encryption policy is supported by this kernel and its encryption
1007 * key is available, then the lookup is assumed to be by plaintext name;
1008 * otherwise, it is assumed to be by no-key name.
1009 *
1010 * This will set DCACHE_NOKEY_NAME on the dentry if the lookup is by no-key
1011 * name. In this case the filesystem must assign the dentry a dentry_operations
1012 * which contains fscrypt_d_revalidate (or contains a d_revalidate method that
1013 * calls fscrypt_d_revalidate), so that the dentry will be invalidated if the
1014 * directory's encryption key is later added.
1015 *
1016 * Return: 0 on success; -ENOENT if the directory's key is unavailable but the
1017 * filename isn't a valid no-key name, so a negative dentry should be created;
1018 * or another -errno code.
1019 */
1020static inline int fscrypt_prepare_lookup(struct inode *dir,
1021 struct dentry *dentry,
1022 struct fscrypt_name *fname)
1023{
1024 if (IS_ENCRYPTED(dir))
1025 return __fscrypt_prepare_lookup(dir, dentry, fname);
1026
1027 memset(fname, 0, sizeof(*fname));
1028 fname->usr_fname = &dentry->d_name;
1029 fname->disk_name.name = (unsigned char *)dentry->d_name.name;
1030 fname->disk_name.len = dentry->d_name.len;
1031
1032 fscrypt_prepare_dentry(dentry, is_nokey_name: false);
1033
1034 return 0;
1035}
1036
1037/**
1038 * fscrypt_prepare_readdir() - prepare to read a possibly-encrypted directory
1039 * @dir: the directory inode
1040 *
1041 * If the directory is encrypted and it doesn't already have its encryption key
1042 * set up, try to set it up so that the filenames will be listed in plaintext
1043 * form rather than in no-key form.
1044 *
1045 * Return: 0 on success; -errno on error. Note that the encryption key being
1046 * unavailable is not considered an error. It is also not an error if
1047 * the encryption policy is unsupported by this kernel; that is treated
1048 * like the key being unavailable, so that files can still be deleted.
1049 */
1050static inline int fscrypt_prepare_readdir(struct inode *dir)
1051{
1052 if (IS_ENCRYPTED(dir))
1053 return __fscrypt_prepare_readdir(dir);
1054 return 0;
1055}
1056
1057/**
1058 * fscrypt_prepare_setattr() - prepare to change a possibly-encrypted inode's
1059 * attributes
1060 * @dentry: dentry through which the inode is being changed
1061 * @attr: attributes to change
1062 *
1063 * Prepare for ->setattr() on a possibly-encrypted inode. On an encrypted file,
1064 * most attribute changes are allowed even without the encryption key. However,
1065 * without the encryption key we do have to forbid truncates. This is needed
1066 * because the size being truncated to may not be a multiple of the filesystem
1067 * block size, and in that case we'd have to decrypt the final block, zero the
1068 * portion past i_size, and re-encrypt it. (We *could* allow truncating to a
1069 * filesystem block boundary, but it's simpler to just forbid all truncates ---
1070 * and we already forbid all other contents modifications without the key.)
1071 *
1072 * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
1073 * if a problem occurred while setting up the encryption key.
1074 */
1075static inline int fscrypt_prepare_setattr(struct dentry *dentry,
1076 struct iattr *attr)
1077{
1078 if (IS_ENCRYPTED(d_inode(dentry)))
1079 return __fscrypt_prepare_setattr(dentry, attr);
1080 return 0;
1081}
1082
1083/**
1084 * fscrypt_encrypt_symlink() - encrypt the symlink target if needed
1085 * @inode: symlink inode
1086 * @target: plaintext symlink target
1087 * @len: length of @target excluding null terminator
1088 * @disk_link: (in/out) the on-disk symlink target being prepared
1089 *
1090 * If the symlink target needs to be encrypted, then this function encrypts it
1091 * into @disk_link->name. fscrypt_prepare_symlink() must have been called
1092 * previously to compute @disk_link->len. If the filesystem did not allocate a
1093 * buffer for @disk_link->name after calling fscrypt_prepare_link(), then one
1094 * will be kmalloc()'ed and the filesystem will be responsible for freeing it.
1095 *
1096 * Return: 0 on success, -errno on failure
1097 */
1098static inline int fscrypt_encrypt_symlink(struct inode *inode,
1099 const char *target,
1100 unsigned int len,
1101 struct fscrypt_str *disk_link)
1102{
1103 if (IS_ENCRYPTED(inode))
1104 return __fscrypt_encrypt_symlink(inode, target, len, disk_link);
1105 return 0;
1106}
1107
1108/* If *pagep is a bounce page, free it and set *pagep to the pagecache page */
1109static inline void fscrypt_finalize_bounce_page(struct page **pagep)
1110{
1111 struct page *page = *pagep;
1112
1113 if (fscrypt_is_bounce_page(page)) {
1114 *pagep = fscrypt_pagecache_page(bounce_page: page);
1115 fscrypt_free_bounce_page(bounce_page: page);
1116 }
1117}
1118
1119#endif /* _LINUX_FSCRYPT_H */
1120

source code of linux/include/linux/fscrypt.h

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