fscrypt.h

   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	 * The offset of the pointer to struct fscrypt_inode_info in the
  66	 * filesystem-specific part of the inode, relative to the beginning of
  67	 * the common part of the inode (the 'struct inode').
  68	 */
  69	ptrdiff_t inode_info_offs;
  70
  71	/*
  72	 * If set, then fs/crypto/ will allocate a global bounce page pool the
  73	 * first time an encryption key is set up for a file.  The bounce page
  74	 * pool is required by the following functions:
  75	 *
  76	 * - fscrypt_encrypt_pagecache_blocks()
  77	 * - fscrypt_zeroout_range() for files not using inline crypto
  78	 *
  79	 * If the filesystem doesn't use those, it doesn't need to set this.
  80	 */
  81	unsigned int needs_bounce_pages : 1;
  82
  83	/*
  84	 * If set, then fs/crypto/ will allow the use of encryption settings
  85	 * that assume inode numbers fit in 32 bits (i.e.
  86	 * FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64}), provided that the other
  87	 * prerequisites for these settings are also met.  This is only useful
  88	 * if the filesystem wants to support inline encryption hardware that is
  89	 * limited to 32-bit or 64-bit data unit numbers and where programming
  90	 * keyslots is very slow.
  91	 */
  92	unsigned int has_32bit_inodes : 1;
  93
  94	/*
  95	 * If set, then fs/crypto/ will allow users to select a crypto data unit
  96	 * size that is less than the filesystem block size.  This is done via
  97	 * the log2_data_unit_size field of the fscrypt policy.  This flag is
  98	 * not compatible with filesystems that encrypt variable-length blocks
  99	 * (i.e. blocks that aren't all equal to filesystem's block size), for
 100	 * example as a result of compression.  It's also not compatible with
 101	 * the fscrypt_encrypt_block_inplace() and
 102	 * fscrypt_decrypt_block_inplace() functions.
 103	 */
 104	unsigned int supports_subblock_data_units : 1;
 105
 106	/*
 107	 * This field exists only for backwards compatibility reasons and should
 108	 * only be set by the filesystems that are setting it already.  It
 109	 * contains the filesystem-specific key description prefix that is
 110	 * accepted for "logon" keys for v1 fscrypt policies.  This
 111	 * functionality is deprecated in favor of the generic prefix
 112	 * "fscrypt:", which itself is deprecated in favor of the filesystem
 113	 * keyring ioctls such as FS_IOC_ADD_ENCRYPTION_KEY.  Filesystems that
 114	 * are newly adding fscrypt support should not set this field.
 115	 */
 116	const char *legacy_key_prefix;
 117
 118	/*
 119	 * Get the fscrypt context of the given inode.
 120	 *
 121	 * @inode: the inode whose context to get
 122	 * @ctx: the buffer into which to get the context
 123	 * @len: length of the @ctx buffer in bytes
 124	 *
 125	 * Return: On success, returns the length of the context in bytes; this
 126	 *	   may be less than @len.  On failure, returns -ENODATA if the
 127	 *	   inode doesn't have a context, -ERANGE if the context is
 128	 *	   longer than @len, or another -errno code.
 129	 */
 130	int (*get_context)(struct inode *inode, void *ctx, size_t len);
 131
 132	/*
 133	 * Set an fscrypt context on the given inode.
 134	 *
 135	 * @inode: the inode whose context to set.  The inode won't already have
 136	 *	   an fscrypt context.
 137	 * @ctx: the context to set
 138	 * @len: length of @ctx in bytes (at most FSCRYPT_SET_CONTEXT_MAX_SIZE)
 139	 * @fs_data: If called from fscrypt_set_context(), this will be the
 140	 *	     value the filesystem passed to fscrypt_set_context().
 141	 *	     Otherwise (i.e. when called from
 142	 *	     FS_IOC_SET_ENCRYPTION_POLICY) this will be NULL.
 143	 *
 144	 * i_rwsem will be held for write.
 145	 *
 146	 * Return: 0 on success, -errno on failure.
 147	 */
 148	int (*set_context)(struct inode *inode, const void *ctx, size_t len,
 149			   void *fs_data);
 150
 151	/*
 152	 * Get the dummy fscrypt policy in use on the filesystem (if any).
 153	 *
 154	 * Filesystems only need to implement this function if they support the
 155	 * test_dummy_encryption mount option.
 156	 *
 157	 * Return: A pointer to the dummy fscrypt policy, if the filesystem is
 158	 *	   mounted with test_dummy_encryption; otherwise NULL.
 159	 */
 160	const union fscrypt_policy *(*get_dummy_policy)(struct super_block *sb);
 161
 162	/*
 163	 * Check whether a directory is empty.  i_rwsem will be held for write.
 164	 */
 165	bool (*empty_dir)(struct inode *inode);
 166
 167	/*
 168	 * Check whether the filesystem's inode numbers and UUID are stable,
 169	 * meaning that they will never be changed even by offline operations
 170	 * such as filesystem shrinking and therefore can be used in the
 171	 * encryption without the possibility of files becoming unreadable.
 172	 *
 173	 * Filesystems only need to implement this function if they want to
 174	 * support the FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64} flags.  These
 175	 * flags are designed to work around the limitations of UFS and eMMC
 176	 * inline crypto hardware, and they shouldn't be used in scenarios where
 177	 * such hardware isn't being used.
 178	 *
 179	 * Leaving this NULL is equivalent to always returning false.
 180	 */
 181	bool (*has_stable_inodes)(struct super_block *sb);
 182
 183	/*
 184	 * Return an array of pointers to the block devices to which the
 185	 * filesystem may write encrypted file contents, NULL if the filesystem
 186	 * only has a single such block device, or an ERR_PTR() on error.
 187	 *
 188	 * On successful non-NULL return, *num_devs is set to the number of
 189	 * devices in the returned array.  The caller must free the returned
 190	 * array using kfree().
 191	 *
 192	 * If the filesystem can use multiple block devices (other than block
 193	 * devices that aren't used for encrypted file contents, such as
 194	 * external journal devices), and wants to support inline encryption,
 195	 * then it must implement this function.  Otherwise it's not needed.
 196	 */
 197	struct block_device **(*get_devices)(struct super_block *sb,
 198					     unsigned int *num_devs);
 199};
 200
 201int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name,
 202			 struct dentry *dentry, unsigned int flags);
 203
 204/*
 205 * Returns the address of the fscrypt info pointer within the
 206 * filesystem-specific part of the inode.  (To save memory on filesystems that
 207 * don't support fscrypt, a field in 'struct inode' itself is no longer used.)
 208 */
 209static inline struct fscrypt_inode_info **
 210fscrypt_inode_info_addr(const struct inode *inode)
 211{
 212	VFS_WARN_ON_ONCE(inode->i_sb->s_cop->inode_info_offs == 0);
 213	return (void *)inode + inode->i_sb->s_cop->inode_info_offs;
 214}
 215
 216/*
 217 * Load the inode's fscrypt info pointer, using a raw dereference.  Since this
 218 * uses a raw dereference with no memory barrier, it is appropriate to use only
 219 * when the caller knows the inode's key setup already happened, resulting in
 220 * non-NULL fscrypt info.  E.g., the file contents en/decryption functions use
 221 * this, since fscrypt_file_open() set up the key.
 222 */
 223static inline struct fscrypt_inode_info *
 224fscrypt_get_inode_info_raw(const struct inode *inode)
 225{
 226	struct fscrypt_inode_info *ci = *fscrypt_inode_info_addr(inode);
 227
 228	VFS_WARN_ON_ONCE(ci == NULL);
 229	return ci;
 230}
 231
 232static inline struct fscrypt_inode_info *
 233fscrypt_get_inode_info(const struct inode *inode)
 234{
 235	/*
 236	 * Pairs with the cmpxchg_release() in fscrypt_setup_encryption_info().
 237	 * I.e., another task may publish the fscrypt info concurrently,
 238	 * executing a RELEASE barrier.  Use smp_load_acquire() here to safely
 239	 * ACQUIRE the memory the other task published.
 240	 */
 241	return smp_load_acquire(fscrypt_inode_info_addr(inode));
 242}
 243
 244/**
 245 * fscrypt_needs_contents_encryption() - check whether an inode needs
 246 *					 contents encryption
 247 * @inode: the inode to check
 248 *
 249 * Return: %true iff the inode is an encrypted regular file and the kernel was
 250 * built with fscrypt support.
 251 *
 252 * If you need to know whether the encrypt bit is set even when the kernel was
 253 * built without fscrypt support, you must use IS_ENCRYPTED() directly instead.
 254 */
 255static inline bool fscrypt_needs_contents_encryption(const struct inode *inode)
 256{
 257	return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode);
 258}
 259
 260/*
 261 * When d_splice_alias() moves a directory's no-key alias to its
 262 * plaintext alias as a result of the encryption key being added,
 263 * DCACHE_NOKEY_NAME must be cleared and there might be an opportunity
 264 * to disable d_revalidate.  Note that we don't have to support the
 265 * inverse operation because fscrypt doesn't allow no-key names to be
 266 * the source or target of a rename().
 267 */
 268static inline void fscrypt_handle_d_move(struct dentry *dentry)
 269{
 270	/*
 271	 * VFS calls fscrypt_handle_d_move even for non-fscrypt
 272	 * filesystems.
 273	 */
 274	if (dentry->d_flags & DCACHE_NOKEY_NAME) {
 275		dentry->d_flags &= ~DCACHE_NOKEY_NAME;
 276
 277		/*
 278		 * Other filesystem features might be handling dentry
 279		 * revalidation, in which case it cannot be disabled.
 280		 */
 281		if (dentry->d_op->d_revalidate == fscrypt_d_revalidate)
 282			dentry->d_flags &= ~DCACHE_OP_REVALIDATE;
 283	}
 284}
 285
 286/**
 287 * fscrypt_is_nokey_name() - test whether a dentry is a no-key name
 288 * @dentry: the dentry to check
 289 *
 290 * This returns true if the dentry is a no-key dentry.  A no-key dentry is a
 291 * dentry that was created in an encrypted directory that hasn't had its
 292 * encryption key added yet.  Such dentries may be either positive or negative.
 293 *
 294 * When a filesystem is asked to create a new filename in an encrypted directory
 295 * and the new filename's dentry is a no-key dentry, it must fail the operation
 296 * with ENOKEY.  This includes ->create(), ->mkdir(), ->mknod(), ->symlink(),
 297 * ->rename(), and ->link().  (However, ->rename() and ->link() are already
 298 * handled by fscrypt_prepare_rename() and fscrypt_prepare_link().)
 299 *
 300 * This is necessary because creating a filename requires the directory's
 301 * encryption key, but just checking for the key on the directory inode during
 302 * the final filesystem operation doesn't guarantee that the key was available
 303 * during the preceding dentry lookup.  And the key must have already been
 304 * available during the dentry lookup in order for it to have been checked
 305 * whether the filename already exists in the directory and for the new file's
 306 * dentry not to be invalidated due to it incorrectly having the no-key flag.
 307 *
 308 * Return: %true if the dentry is a no-key name
 309 */
 310static inline bool fscrypt_is_nokey_name(const struct dentry *dentry)
 311{
 312	return dentry->d_flags & DCACHE_NOKEY_NAME;
 313}
 314
 315static inline void fscrypt_prepare_dentry(struct dentry *dentry,
 316					  bool is_nokey_name)
 317{
 318	/*
 319	 * This code tries to only take ->d_lock when necessary to write
 320	 * to ->d_flags.  We shouldn't be peeking on d_flags for
 321	 * DCACHE_OP_REVALIDATE unlocked, but in the unlikely case
 322	 * there is a race, the worst it can happen is that we fail to
 323	 * unset DCACHE_OP_REVALIDATE and pay the cost of an extra
 324	 * d_revalidate.
 325	 */
 326	if (is_nokey_name) {
 327		spin_lock(&dentry->d_lock);
 328		dentry->d_flags |= DCACHE_NOKEY_NAME;
 329		spin_unlock(&dentry->d_lock);
 330	} else if (dentry->d_flags & DCACHE_OP_REVALIDATE &&
 331		   dentry->d_op->d_revalidate == fscrypt_d_revalidate) {
 332		/*
 333		 * Unencrypted dentries and encrypted dentries where the
 334		 * key is available are always valid from fscrypt
 335		 * perspective. Avoid the cost of calling
 336		 * fscrypt_d_revalidate unnecessarily.
 337		 */
 338		spin_lock(&dentry->d_lock);
 339		dentry->d_flags &= ~DCACHE_OP_REVALIDATE;
 340		spin_unlock(&dentry->d_lock);
 341	}
 342}
 343
 344/* crypto.c */
 345void fscrypt_enqueue_decrypt_work(struct work_struct *);
 346
 347struct page *fscrypt_encrypt_pagecache_blocks(struct folio *folio,
 348		size_t len, size_t offs, gfp_t gfp_flags);
 349int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page,
 350				  unsigned int len, unsigned int offs,
 351				  u64 lblk_num);
 352
 353int fscrypt_decrypt_pagecache_blocks(struct folio *folio, size_t len,
 354				     size_t offs);
 355int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page,
 356				  unsigned int len, unsigned int offs,
 357				  u64 lblk_num);
 358
 359static inline bool fscrypt_is_bounce_page(struct page *page)
 360{
 361	return page->mapping == NULL;
 362}
 363
 364static inline struct page *fscrypt_pagecache_page(struct page *bounce_page)
 365{
 366	return (struct page *)page_private(bounce_page);
 367}
 368
 369static inline bool fscrypt_is_bounce_folio(const struct folio *folio)
 370{
 371	return folio->mapping == NULL;
 372}
 373
 374static inline
 375struct folio *fscrypt_pagecache_folio(const struct folio *bounce_folio)
 376{
 377	return bounce_folio->private;
 378}
 379
 380void fscrypt_free_bounce_page(struct page *bounce_page);
 381
 382/* policy.c */
 383int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg);
 384int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg);
 385int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *arg);
 386int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg);
 387int fscrypt_has_permitted_context(struct inode *parent, struct inode *child);
 388int fscrypt_context_for_new_inode(void *ctx, struct inode *inode);
 389int fscrypt_set_context(struct inode *inode, void *fs_data);
 390
 391struct fscrypt_dummy_policy {
 392	const union fscrypt_policy *policy;
 393};
 394
 395int fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param,
 396				    struct fscrypt_dummy_policy *dummy_policy);
 397bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1,
 398				  const struct fscrypt_dummy_policy *p2);
 399void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep,
 400					struct super_block *sb);
 401static inline bool
 402fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy)
 403{
 404	return dummy_policy->policy != NULL;
 405}
 406static inline void
 407fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy)
 408{
 409	kfree(dummy_policy->policy);
 410	dummy_policy->policy = NULL;
 411}
 412
 413/* keyring.c */
 414void fscrypt_destroy_keyring(struct super_block *sb);
 415int fscrypt_ioctl_add_key(struct file *filp, void __user *arg);
 416int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg);
 417int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *arg);
 418int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg);
 419
 420/* keysetup.c */
 421int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode,
 422			      bool *encrypt_ret);
 423void fscrypt_put_encryption_info(struct inode *inode);
 424void fscrypt_free_inode(struct inode *inode);
 425int fscrypt_drop_inode(struct inode *inode);
 426
 427/* fname.c */
 428int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
 429			  u8 *out, unsigned int olen);
 430bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len,
 431				  u32 max_len, u32 *encrypted_len_ret);
 432int fscrypt_setup_filename(struct inode *inode, const struct qstr *iname,
 433			   int lookup, struct fscrypt_name *fname);
 434
 435static inline void fscrypt_free_filename(struct fscrypt_name *fname)
 436{
 437	kfree(fname->crypto_buf.name);
 438}
 439
 440int fscrypt_fname_alloc_buffer(u32 max_encrypted_len,
 441			       struct fscrypt_str *crypto_str);
 442void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str);
 443int fscrypt_fname_disk_to_usr(const struct inode *inode,
 444			      u32 hash, u32 minor_hash,
 445			      const struct fscrypt_str *iname,
 446			      struct fscrypt_str *oname);
 447bool fscrypt_match_name(const struct fscrypt_name *fname,
 448			const u8 *de_name, u32 de_name_len);
 449u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name);
 450
 451/* bio.c */
 452bool fscrypt_decrypt_bio(struct bio *bio);
 453int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 454			  sector_t pblk, unsigned int len);
 455
 456/* hooks.c */
 457int fscrypt_file_open(struct inode *inode, struct file *filp);
 458int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
 459			   struct dentry *dentry);
 460int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry,
 461			     struct inode *new_dir, struct dentry *new_dentry,
 462			     unsigned int flags);
 463int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
 464			     struct fscrypt_name *fname);
 465int fscrypt_prepare_lookup_partial(struct inode *dir, struct dentry *dentry);
 466int __fscrypt_prepare_readdir(struct inode *dir);
 467int __fscrypt_prepare_setattr(struct dentry *dentry, struct iattr *attr);
 468int fscrypt_prepare_setflags(struct inode *inode,
 469			     unsigned int oldflags, unsigned int flags);
 470int fscrypt_prepare_symlink(struct inode *dir, const char *target,
 471			    unsigned int len, unsigned int max_len,
 472			    struct fscrypt_str *disk_link);
 473int __fscrypt_encrypt_symlink(struct inode *inode, const char *target,
 474			      unsigned int len, struct fscrypt_str *disk_link);
 475const char *fscrypt_get_symlink(struct inode *inode, const void *caddr,
 476				unsigned int max_size,
 477				struct delayed_call *done);
 478int fscrypt_symlink_getattr(const struct path *path, struct kstat *stat);
 479static inline void fscrypt_set_ops(struct super_block *sb,
 480				   const struct fscrypt_operations *s_cop)
 481{
 482	sb->s_cop = s_cop;
 483}
 484#else  /* !CONFIG_FS_ENCRYPTION */
 485
 486static inline struct fscrypt_inode_info *
 487fscrypt_get_inode_info(const struct inode *inode)
 488{
 489	return NULL;
 490}
 491
 492static inline bool fscrypt_needs_contents_encryption(const struct inode *inode)
 493{
 494	return false;
 495}
 496
 497static inline void fscrypt_handle_d_move(struct dentry *dentry)
 498{
 499}
 500
 501static inline bool fscrypt_is_nokey_name(const struct dentry *dentry)
 502{
 503	return false;
 504}
 505
 506static inline void fscrypt_prepare_dentry(struct dentry *dentry,
 507					  bool is_nokey_name)
 508{
 509}
 510
 511/* crypto.c */
 512static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work)
 513{
 514}
 515
 516static inline struct page *fscrypt_encrypt_pagecache_blocks(struct folio *folio,
 517		size_t len, size_t offs, gfp_t gfp_flags)
 518{
 519	return ERR_PTR(-EOPNOTSUPP);
 520}
 521
 522static inline int fscrypt_encrypt_block_inplace(const struct inode *inode,
 523						struct page *page,
 524						unsigned int len,
 525						unsigned int offs, u64 lblk_num)
 526{
 527	return -EOPNOTSUPP;
 528}
 529
 530static inline int fscrypt_decrypt_pagecache_blocks(struct folio *folio,
 531						   size_t len, size_t offs)
 532{
 533	return -EOPNOTSUPP;
 534}
 535
 536static inline int fscrypt_decrypt_block_inplace(const struct inode *inode,
 537						struct page *page,
 538						unsigned int len,
 539						unsigned int offs, u64 lblk_num)
 540{
 541	return -EOPNOTSUPP;
 542}
 543
 544static inline bool fscrypt_is_bounce_page(struct page *page)
 545{
 546	return false;
 547}
 548
 549static inline struct page *fscrypt_pagecache_page(struct page *bounce_page)
 550{
 551	WARN_ON_ONCE(1);
 552	return ERR_PTR(-EINVAL);
 553}
 554
 555static inline bool fscrypt_is_bounce_folio(const struct folio *folio)
 556{
 557	return false;
 558}
 559
 560static inline
 561struct folio *fscrypt_pagecache_folio(const struct folio *bounce_folio)
 562{
 563	WARN_ON_ONCE(1);
 564	return ERR_PTR(-EINVAL);
 565}
 566
 567static inline void fscrypt_free_bounce_page(struct page *bounce_page)
 568{
 569}
 570
 571/* policy.c */
 572static inline int fscrypt_ioctl_set_policy(struct file *filp,
 573					   const void __user *arg)
 574{
 575	return -EOPNOTSUPP;
 576}
 577
 578static inline int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
 579{
 580	return -EOPNOTSUPP;
 581}
 582
 583static inline int fscrypt_ioctl_get_policy_ex(struct file *filp,
 584					      void __user *arg)
 585{
 586	return -EOPNOTSUPP;
 587}
 588
 589static inline int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg)
 590{
 591	return -EOPNOTSUPP;
 592}
 593
 594static inline int fscrypt_has_permitted_context(struct inode *parent,
 595						struct inode *child)
 596{
 597	return 0;
 598}
 599
 600static inline int fscrypt_set_context(struct inode *inode, void *fs_data)
 601{
 602	return -EOPNOTSUPP;
 603}
 604
 605struct fscrypt_dummy_policy {
 606};
 607
 608static inline int
 609fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param,
 610				    struct fscrypt_dummy_policy *dummy_policy)
 611{
 612	return -EINVAL;
 613}
 614
 615static inline bool
 616fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1,
 617			     const struct fscrypt_dummy_policy *p2)
 618{
 619	return true;
 620}
 621
 622static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq,
 623						      char sep,
 624						      struct super_block *sb)
 625{
 626}
 627
 628static inline bool
 629fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy)
 630{
 631	return false;
 632}
 633
 634static inline void
 635fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy)
 636{
 637}
 638
 639/* keyring.c */
 640static inline void fscrypt_destroy_keyring(struct super_block *sb)
 641{
 642}
 643
 644static inline int fscrypt_ioctl_add_key(struct file *filp, void __user *arg)
 645{
 646	return -EOPNOTSUPP;
 647}
 648
 649static inline int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg)
 650{
 651	return -EOPNOTSUPP;
 652}
 653
 654static inline int fscrypt_ioctl_remove_key_all_users(struct file *filp,
 655						     void __user *arg)
 656{
 657	return -EOPNOTSUPP;
 658}
 659
 660static inline int fscrypt_ioctl_get_key_status(struct file *filp,
 661					       void __user *arg)
 662{
 663	return -EOPNOTSUPP;
 664}
 665
 666/* keysetup.c */
 667
 668static inline int fscrypt_prepare_new_inode(struct inode *dir,
 669					    struct inode *inode,
 670					    bool *encrypt_ret)
 671{
 672	if (IS_ENCRYPTED(dir))
 673		return -EOPNOTSUPP;
 674	return 0;
 675}
 676
 677static inline void fscrypt_put_encryption_info(struct inode *inode)
 678{
 679	return;
 680}
 681
 682static inline void fscrypt_free_inode(struct inode *inode)
 683{
 684}
 685
 686static inline int fscrypt_drop_inode(struct inode *inode)
 687{
 688	return 0;
 689}
 690
 691 /* fname.c */
 692static inline int fscrypt_setup_filename(struct inode *dir,
 693					 const struct qstr *iname,
 694					 int lookup, struct fscrypt_name *fname)
 695{
 696	if (IS_ENCRYPTED(dir))
 697		return -EOPNOTSUPP;
 698
 699	memset(fname, 0, sizeof(*fname));
 700	fname->usr_fname = iname;
 701	fname->disk_name.name = (unsigned char *)iname->name;
 702	fname->disk_name.len = iname->len;
 703	return 0;
 704}
 705
 706static inline void fscrypt_free_filename(struct fscrypt_name *fname)
 707{
 708	return;
 709}
 710
 711static inline int fscrypt_fname_alloc_buffer(u32 max_encrypted_len,
 712					     struct fscrypt_str *crypto_str)
 713{
 714	return -EOPNOTSUPP;
 715}
 716
 717static inline void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str)
 718{
 719	return;
 720}
 721
 722static inline int fscrypt_fname_disk_to_usr(const struct inode *inode,
 723					    u32 hash, u32 minor_hash,
 724					    const struct fscrypt_str *iname,
 725					    struct fscrypt_str *oname)
 726{
 727	return -EOPNOTSUPP;
 728}
 729
 730static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
 731				      const u8 *de_name, u32 de_name_len)
 732{
 733	/* Encryption support disabled; use standard comparison */
 734	if (de_name_len != fname->disk_name.len)
 735		return false;
 736	return !memcmp(de_name, fname->disk_name.name, fname->disk_name.len);
 737}
 738
 739static inline u64 fscrypt_fname_siphash(const struct inode *dir,
 740					const struct qstr *name)
 741{
 742	WARN_ON_ONCE(1);
 743	return 0;
 744}
 745
 746static inline int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name,
 747				       struct dentry *dentry, unsigned int flags)
 748{
 749	return 1;
 750}
 751
 752/* bio.c */
 753static inline bool fscrypt_decrypt_bio(struct bio *bio)
 754{
 755	return true;
 756}
 757
 758static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 759					sector_t pblk, unsigned int len)
 760{
 761	return -EOPNOTSUPP;
 762}
 763
 764/* hooks.c */
 765
 766static inline int fscrypt_file_open(struct inode *inode, struct file *filp)
 767{
 768	if (IS_ENCRYPTED(inode))
 769		return -EOPNOTSUPP;
 770	return 0;
 771}
 772
 773static inline int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
 774					 struct dentry *dentry)
 775{
 776	return -EOPNOTSUPP;
 777}
 778
 779static inline int __fscrypt_prepare_rename(struct inode *old_dir,
 780					   struct dentry *old_dentry,
 781					   struct inode *new_dir,
 782					   struct dentry *new_dentry,
 783					   unsigned int flags)
 784{
 785	return -EOPNOTSUPP;
 786}
 787
 788static inline int __fscrypt_prepare_lookup(struct inode *dir,
 789					   struct dentry *dentry,
 790					   struct fscrypt_name *fname)
 791{
 792	return -EOPNOTSUPP;
 793}
 794
 795static inline int fscrypt_prepare_lookup_partial(struct inode *dir,
 796						 struct dentry *dentry)
 797{
 798	return -EOPNOTSUPP;
 799}
 800
 801static inline int __fscrypt_prepare_readdir(struct inode *dir)
 802{
 803	return -EOPNOTSUPP;
 804}
 805
 806static inline int __fscrypt_prepare_setattr(struct dentry *dentry,
 807					    struct iattr *attr)
 808{
 809	return -EOPNOTSUPP;
 810}
 811
 812static inline int fscrypt_prepare_setflags(struct inode *inode,
 813					   unsigned int oldflags,
 814					   unsigned int flags)
 815{
 816	return 0;
 817}
 818
 819static inline int fscrypt_prepare_symlink(struct inode *dir,
 820					  const char *target,
 821					  unsigned int len,
 822					  unsigned int max_len,
 823					  struct fscrypt_str *disk_link)
 824{
 825	if (IS_ENCRYPTED(dir))
 826		return -EOPNOTSUPP;
 827	disk_link->name = (unsigned char *)target;
 828	disk_link->len = len + 1;
 829	if (disk_link->len > max_len)
 830		return -ENAMETOOLONG;
 831	return 0;
 832}
 833
 834static inline int __fscrypt_encrypt_symlink(struct inode *inode,
 835					    const char *target,
 836					    unsigned int len,
 837					    struct fscrypt_str *disk_link)
 838{
 839	return -EOPNOTSUPP;
 840}
 841
 842static inline const char *fscrypt_get_symlink(struct inode *inode,
 843					      const void *caddr,
 844					      unsigned int max_size,
 845					      struct delayed_call *done)
 846{
 847	return ERR_PTR(-EOPNOTSUPP);
 848}
 849
 850static inline int fscrypt_symlink_getattr(const struct path *path,
 851					  struct kstat *stat)
 852{
 853	return -EOPNOTSUPP;
 854}
 855
 856static inline void fscrypt_set_ops(struct super_block *sb,
 857				   const struct fscrypt_operations *s_cop)
 858{
 859}
 860
 861#endif	/* !CONFIG_FS_ENCRYPTION */
 862
 863/* inline_crypt.c */
 864#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
 865
 866bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode);
 867
 868void fscrypt_set_bio_crypt_ctx(struct bio *bio,
 869			       const struct inode *inode, u64 first_lblk,
 870			       gfp_t gfp_mask);
 871
 872void fscrypt_set_bio_crypt_ctx_bh(struct bio *bio,
 873				  const struct buffer_head *first_bh,
 874				  gfp_t gfp_mask);
 875
 876bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode,
 877			   u64 next_lblk);
 878
 879bool fscrypt_mergeable_bio_bh(struct bio *bio,
 880			      const struct buffer_head *next_bh);
 881
 882bool fscrypt_dio_supported(struct inode *inode);
 883
 884u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, u64 nr_blocks);
 885
 886#else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
 887
 888static inline bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode)
 889{
 890	return false;
 891}
 892
 893static inline void fscrypt_set_bio_crypt_ctx(struct bio *bio,
 894					     const struct inode *inode,
 895					     u64 first_lblk, gfp_t gfp_mask) { }
 896
 897static inline void fscrypt_set_bio_crypt_ctx_bh(
 898					 struct bio *bio,
 899					 const struct buffer_head *first_bh,
 900					 gfp_t gfp_mask) { }
 901
 902static inline bool fscrypt_mergeable_bio(struct bio *bio,
 903					 const struct inode *inode,
 904					 u64 next_lblk)
 905{
 906	return true;
 907}
 908
 909static inline bool fscrypt_mergeable_bio_bh(struct bio *bio,
 910					    const struct buffer_head *next_bh)
 911{
 912	return true;
 913}
 914
 915static inline bool fscrypt_dio_supported(struct inode *inode)
 916{
 917	return !fscrypt_needs_contents_encryption(inode);
 918}
 919
 920static inline u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk,
 921					  u64 nr_blocks)
 922{
 923	return nr_blocks;
 924}
 925#endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
 926
 927/**
 928 * fscrypt_inode_uses_inline_crypto() - test whether an inode uses inline
 929 *					encryption
 930 * @inode: an inode. If encrypted, its key must be set up.
 931 *
 932 * Return: true if the inode requires file contents encryption and if the
 933 *	   encryption should be done in the block layer via blk-crypto rather
 934 *	   than in the filesystem layer.
 935 */
 936static inline bool fscrypt_inode_uses_inline_crypto(const struct inode *inode)
 937{
 938	return fscrypt_needs_contents_encryption(inode) &&
 939	       __fscrypt_inode_uses_inline_crypto(inode);
 940}
 941
 942/**
 943 * fscrypt_inode_uses_fs_layer_crypto() - test whether an inode uses fs-layer
 944 *					  encryption
 945 * @inode: an inode. If encrypted, its key must be set up.
 946 *
 947 * Return: true if the inode requires file contents encryption and if the
 948 *	   encryption should be done in the filesystem layer rather than in the
 949 *	   block layer via blk-crypto.
 950 */
 951static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode)
 952{
 953	return fscrypt_needs_contents_encryption(inode) &&
 954	       !__fscrypt_inode_uses_inline_crypto(inode);
 955}
 956
 957/**
 958 * fscrypt_has_encryption_key() - check whether an inode has had its key set up
 959 * @inode: the inode to check
 960 *
 961 * Return: %true if the inode has had its encryption key set up, else %false.
 962 *
 963 * Usually this should be preceded by fscrypt_get_encryption_info() to try to
 964 * set up the key first.
 965 */
 966static inline bool fscrypt_has_encryption_key(const struct inode *inode)
 967{
 968	return fscrypt_get_inode_info(inode) != NULL;
 969}
 970
 971/**
 972 * fscrypt_prepare_link() - prepare to link an inode into a possibly-encrypted
 973 *			    directory
 974 * @old_dentry: an existing dentry for the inode being linked
 975 * @dir: the target directory
 976 * @dentry: negative dentry for the target filename
 977 *
 978 * A new link can only be added to an encrypted directory if the directory's
 979 * encryption key is available --- since otherwise we'd have no way to encrypt
 980 * the filename.
 981 *
 982 * We also verify that the link will not violate the constraint that all files
 983 * in an encrypted directory tree use the same encryption policy.
 984 *
 985 * Return: 0 on success, -ENOKEY if the directory's encryption key is missing,
 986 * -EXDEV if the link would result in an inconsistent encryption policy, or
 987 * another -errno code.
 988 */
 989static inline int fscrypt_prepare_link(struct dentry *old_dentry,
 990				       struct inode *dir,
 991				       struct dentry *dentry)
 992{
 993	if (IS_ENCRYPTED(dir))
 994		return __fscrypt_prepare_link(d_inode(old_dentry), dir, dentry);
 995	return 0;
 996}
 997
 998/**
 999 * fscrypt_prepare_rename() - prepare for a rename between possibly-encrypted
1000 *			      directories
1001 * @old_dir: source directory
1002 * @old_dentry: dentry for source file
1003 * @new_dir: target directory
1004 * @new_dentry: dentry for target location (may be negative unless exchanging)
1005 * @flags: rename flags (we care at least about %RENAME_EXCHANGE)
1006 *
1007 * Prepare for ->rename() where the source and/or target directories may be
1008 * encrypted.  A new link can only be added to an encrypted directory if the
1009 * directory's encryption key is available --- since otherwise we'd have no way
1010 * to encrypt the filename.  A rename to an existing name, on the other hand,
1011 * *is* cryptographically possible without the key.  However, we take the more
1012 * conservative approach and just forbid all no-key renames.
1013 *
1014 * We also verify that the rename will not violate the constraint that all files
1015 * in an encrypted directory tree use the same encryption policy.
1016 *
1017 * Return: 0 on success, -ENOKEY if an encryption key is missing, -EXDEV if the
1018 * rename would cause inconsistent encryption policies, or another -errno code.
1019 */
1020static inline int fscrypt_prepare_rename(struct inode *old_dir,
1021					 struct dentry *old_dentry,
1022					 struct inode *new_dir,
1023					 struct dentry *new_dentry,
1024					 unsigned int flags)
1025{
1026	if (IS_ENCRYPTED(old_dir) || IS_ENCRYPTED(new_dir))
1027		return __fscrypt_prepare_rename(old_dir, old_dentry,
1028						new_dir, new_dentry, flags);
1029	return 0;
1030}
1031
1032/**
1033 * fscrypt_prepare_lookup() - prepare to lookup a name in a possibly-encrypted
1034 *			      directory
1035 * @dir: directory being searched
1036 * @dentry: filename being looked up
1037 * @fname: (output) the name to use to search the on-disk directory
1038 *
1039 * Prepare for ->lookup() in a directory which may be encrypted by determining
1040 * the name that will actually be used to search the directory on-disk.  If the
1041 * directory's encryption policy is supported by this kernel and its encryption
1042 * key is available, then the lookup is assumed to be by plaintext name;
1043 * otherwise, it is assumed to be by no-key name.
1044 *
1045 * This will set DCACHE_NOKEY_NAME on the dentry if the lookup is by no-key
1046 * name.  In this case the filesystem must assign the dentry a dentry_operations
1047 * which contains fscrypt_d_revalidate (or contains a d_revalidate method that
1048 * calls fscrypt_d_revalidate), so that the dentry will be invalidated if the
1049 * directory's encryption key is later added.
1050 *
1051 * Return: 0 on success; -ENOENT if the directory's key is unavailable but the
1052 * filename isn't a valid no-key name, so a negative dentry should be created;
1053 * or another -errno code.
1054 */
1055static inline int fscrypt_prepare_lookup(struct inode *dir,
1056					 struct dentry *dentry,
1057					 struct fscrypt_name *fname)
1058{
1059	if (IS_ENCRYPTED(dir))
1060		return __fscrypt_prepare_lookup(dir, dentry, fname);
1061
1062	memset(fname, 0, sizeof(*fname));
1063	fname->usr_fname = &dentry->d_name;
1064	fname->disk_name.name = (unsigned char *)dentry->d_name.name;
1065	fname->disk_name.len = dentry->d_name.len;
1066
1067	fscrypt_prepare_dentry(dentry, false);
1068
1069	return 0;
1070}
1071
1072/**
1073 * fscrypt_prepare_readdir() - prepare to read a possibly-encrypted directory
1074 * @dir: the directory inode
1075 *
1076 * If the directory is encrypted and it doesn't already have its encryption key
1077 * set up, try to set it up so that the filenames will be listed in plaintext
1078 * form rather than in no-key form.
1079 *
1080 * Return: 0 on success; -errno on error.  Note that the encryption key being
1081 *	   unavailable is not considered an error.  It is also not an error if
1082 *	   the encryption policy is unsupported by this kernel; that is treated
1083 *	   like the key being unavailable, so that files can still be deleted.
1084 */
1085static inline int fscrypt_prepare_readdir(struct inode *dir)
1086{
1087	if (IS_ENCRYPTED(dir))
1088		return __fscrypt_prepare_readdir(dir);
1089	return 0;
1090}
1091
1092/**
1093 * fscrypt_prepare_setattr() - prepare to change a possibly-encrypted inode's
1094 *			       attributes
1095 * @dentry: dentry through which the inode is being changed
1096 * @attr: attributes to change
1097 *
1098 * Prepare for ->setattr() on a possibly-encrypted inode.  On an encrypted file,
1099 * most attribute changes are allowed even without the encryption key.  However,
1100 * without the encryption key we do have to forbid truncates.  This is needed
1101 * because the size being truncated to may not be a multiple of the filesystem
1102 * block size, and in that case we'd have to decrypt the final block, zero the
1103 * portion past i_size, and re-encrypt it.  (We *could* allow truncating to a
1104 * filesystem block boundary, but it's simpler to just forbid all truncates ---
1105 * and we already forbid all other contents modifications without the key.)
1106 *
1107 * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
1108 * if a problem occurred while setting up the encryption key.
1109 */
1110static inline int fscrypt_prepare_setattr(struct dentry *dentry,
1111					  struct iattr *attr)
1112{
1113	if (IS_ENCRYPTED(d_inode(dentry)))
1114		return __fscrypt_prepare_setattr(dentry, attr);
1115	return 0;
1116}
1117
1118/**
1119 * fscrypt_encrypt_symlink() - encrypt the symlink target if needed
1120 * @inode: symlink inode
1121 * @target: plaintext symlink target
1122 * @len: length of @target excluding null terminator
1123 * @disk_link: (in/out) the on-disk symlink target being prepared
1124 *
1125 * If the symlink target needs to be encrypted, then this function encrypts it
1126 * into @disk_link->name.  fscrypt_prepare_symlink() must have been called
1127 * previously to compute @disk_link->len.  If the filesystem did not allocate a
1128 * buffer for @disk_link->name after calling fscrypt_prepare_link(), then one
1129 * will be kmalloc()'ed and the filesystem will be responsible for freeing it.
1130 *
1131 * Return: 0 on success, -errno on failure
1132 */
1133static inline int fscrypt_encrypt_symlink(struct inode *inode,
1134					  const char *target,
1135					  unsigned int len,
1136					  struct fscrypt_str *disk_link)
1137{
1138	if (IS_ENCRYPTED(inode))
1139		return __fscrypt_encrypt_symlink(inode, target, len, disk_link);
1140	return 0;
1141}
1142
1143/* If *pagep is a bounce page, free it and set *pagep to the pagecache page */
1144static inline void fscrypt_finalize_bounce_page(struct page **pagep)
1145{
1146	struct page *page = *pagep;
1147
1148	if (fscrypt_is_bounce_page(page)) {
1149		*pagep = fscrypt_pagecache_page(page);
1150		fscrypt_free_bounce_page(page);
1151	}
1152}
1153
1154#endif	/* _LINUX_FSCRYPT_H */