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_inode_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 /* Crypto operations for filesystems */ 63 struct 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 }; 194 195 int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags); 196 197 static inline struct fscrypt_inode_info * 198 fscrypt_get_inode_info(const struct inode *inode) 199 { 200 /* 201 * Pairs with the cmpxchg_release() in fscrypt_setup_encryption_info(). 202 * I.e., another task may publish ->i_crypt_info concurrently, executing 203 * a RELEASE barrier. We need to use smp_load_acquire() here to safely 204 * ACQUIRE the memory the other task published. 205 */ 206 return smp_load_acquire(&inode->i_crypt_info); 207 } 208 209 /** 210 * fscrypt_needs_contents_encryption() - check whether an inode needs 211 * contents encryption 212 * @inode: the inode to check 213 * 214 * Return: %true iff the inode is an encrypted regular file and the kernel was 215 * built with fscrypt support. 216 * 217 * If you need to know whether the encrypt bit is set even when the kernel was 218 * built without fscrypt support, you must use IS_ENCRYPTED() directly instead. 219 */ 220 static inline bool fscrypt_needs_contents_encryption(const struct inode *inode) 221 { 222 return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode); 223 } 224 225 /* 226 * When d_splice_alias() moves a directory's no-key alias to its 227 * plaintext alias as a result of the encryption key being added, 228 * DCACHE_NOKEY_NAME must be cleared and there might be an opportunity 229 * to disable d_revalidate. Note that we don't have to support the 230 * inverse operation because fscrypt doesn't allow no-key names to be 231 * the source or target of a rename(). 232 */ 233 static inline void fscrypt_handle_d_move(struct dentry *dentry) 234 { 235 /* 236 * VFS calls fscrypt_handle_d_move even for non-fscrypt 237 * filesystems. 238 */ 239 if (dentry->d_flags & DCACHE_NOKEY_NAME) { 240 dentry->d_flags &= ~DCACHE_NOKEY_NAME; 241 242 /* 243 * Other filesystem features might be handling dentry 244 * revalidation, in which case it cannot be disabled. 245 */ 246 if (dentry->d_op->d_revalidate == fscrypt_d_revalidate) 247 dentry->d_flags &= ~DCACHE_OP_REVALIDATE; 248 } 249 } 250 251 /** 252 * fscrypt_is_nokey_name() - test whether a dentry is a no-key name 253 * @dentry: the dentry to check 254 * 255 * This returns true if the dentry is a no-key dentry. A no-key dentry is a 256 * dentry that was created in an encrypted directory that hasn't had its 257 * encryption key added yet. Such dentries may be either positive or negative. 258 * 259 * When a filesystem is asked to create a new filename in an encrypted directory 260 * and the new filename's dentry is a no-key dentry, it must fail the operation 261 * with ENOKEY. This includes ->create(), ->mkdir(), ->mknod(), ->symlink(), 262 * ->rename(), and ->link(). (However, ->rename() and ->link() are already 263 * handled by fscrypt_prepare_rename() and fscrypt_prepare_link().) 264 * 265 * This is necessary because creating a filename requires the directory's 266 * encryption key, but just checking for the key on the directory inode during 267 * the final filesystem operation doesn't guarantee that the key was available 268 * during the preceding dentry lookup. And the key must have already been 269 * available during the dentry lookup in order for it to have been checked 270 * whether the filename already exists in the directory and for the new file's 271 * dentry not to be invalidated due to it incorrectly having the no-key flag. 272 * 273 * Return: %true if the dentry is a no-key name 274 */ 275 static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) 276 { 277 return dentry->d_flags & DCACHE_NOKEY_NAME; 278 } 279 280 static inline void fscrypt_prepare_dentry(struct dentry *dentry, 281 bool is_nokey_name) 282 { 283 /* 284 * This code tries to only take ->d_lock when necessary to write 285 * to ->d_flags. We shouldn't be peeking on d_flags for 286 * DCACHE_OP_REVALIDATE unlocked, but in the unlikely case 287 * there is a race, the worst it can happen is that we fail to 288 * unset DCACHE_OP_REVALIDATE and pay the cost of an extra 289 * d_revalidate. 290 */ 291 if (is_nokey_name) { 292 spin_lock(&dentry->d_lock); 293 dentry->d_flags |= DCACHE_NOKEY_NAME; 294 spin_unlock(&dentry->d_lock); 295 } else if (dentry->d_flags & DCACHE_OP_REVALIDATE && 296 dentry->d_op->d_revalidate == fscrypt_d_revalidate) { 297 /* 298 * Unencrypted dentries and encrypted dentries where the 299 * key is available are always valid from fscrypt 300 * perspective. Avoid the cost of calling 301 * fscrypt_d_revalidate unnecessarily. 302 */ 303 spin_lock(&dentry->d_lock); 304 dentry->d_flags &= ~DCACHE_OP_REVALIDATE; 305 spin_unlock(&dentry->d_lock); 306 } 307 } 308 309 /* crypto.c */ 310 void fscrypt_enqueue_decrypt_work(struct work_struct *); 311 312 struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, 313 unsigned int len, 314 unsigned int offs, 315 gfp_t gfp_flags); 316 int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page, 317 unsigned int len, unsigned int offs, 318 u64 lblk_num, gfp_t gfp_flags); 319 320 int fscrypt_decrypt_pagecache_blocks(struct folio *folio, size_t len, 321 size_t offs); 322 int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page, 323 unsigned int len, unsigned int offs, 324 u64 lblk_num); 325 326 static inline bool fscrypt_is_bounce_page(struct page *page) 327 { 328 return page->mapping == NULL; 329 } 330 331 static inline struct page *fscrypt_pagecache_page(struct page *bounce_page) 332 { 333 return (struct page *)page_private(bounce_page); 334 } 335 336 static inline bool fscrypt_is_bounce_folio(struct folio *folio) 337 { 338 return folio->mapping == NULL; 339 } 340 341 static inline struct folio *fscrypt_pagecache_folio(struct folio *bounce_folio) 342 { 343 return bounce_folio->private; 344 } 345 346 void fscrypt_free_bounce_page(struct page *bounce_page); 347 348 /* policy.c */ 349 int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg); 350 int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg); 351 int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *arg); 352 int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg); 353 int fscrypt_has_permitted_context(struct inode *parent, struct inode *child); 354 int fscrypt_context_for_new_inode(void *ctx, struct inode *inode); 355 int fscrypt_set_context(struct inode *inode, void *fs_data); 356 357 struct fscrypt_dummy_policy { 358 const union fscrypt_policy *policy; 359 }; 360 361 int fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param, 362 struct fscrypt_dummy_policy *dummy_policy); 363 bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1, 364 const struct fscrypt_dummy_policy *p2); 365 void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep, 366 struct super_block *sb); 367 static inline bool 368 fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy) 369 { 370 return dummy_policy->policy != NULL; 371 } 372 static inline void 373 fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy) 374 { 375 kfree(dummy_policy->policy); 376 dummy_policy->policy = NULL; 377 } 378 379 /* keyring.c */ 380 void fscrypt_destroy_keyring(struct super_block *sb); 381 int fscrypt_ioctl_add_key(struct file *filp, void __user *arg); 382 int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg); 383 int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *arg); 384 int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg); 385 386 /* keysetup.c */ 387 int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode, 388 bool *encrypt_ret); 389 void fscrypt_put_encryption_info(struct inode *inode); 390 void fscrypt_free_inode(struct inode *inode); 391 int fscrypt_drop_inode(struct inode *inode); 392 393 /* fname.c */ 394 int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname, 395 u8 *out, unsigned int olen); 396 bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len, 397 u32 max_len, u32 *encrypted_len_ret); 398 int fscrypt_setup_filename(struct inode *inode, const struct qstr *iname, 399 int lookup, struct fscrypt_name *fname); 400 401 static inline void fscrypt_free_filename(struct fscrypt_name *fname) 402 { 403 kfree(fname->crypto_buf.name); 404 } 405 406 int fscrypt_fname_alloc_buffer(u32 max_encrypted_len, 407 struct fscrypt_str *crypto_str); 408 void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str); 409 int fscrypt_fname_disk_to_usr(const struct inode *inode, 410 u32 hash, u32 minor_hash, 411 const struct fscrypt_str *iname, 412 struct fscrypt_str *oname); 413 bool fscrypt_match_name(const struct fscrypt_name *fname, 414 const u8 *de_name, u32 de_name_len); 415 u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name); 416 417 /* bio.c */ 418 bool fscrypt_decrypt_bio(struct bio *bio); 419 int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, 420 sector_t pblk, unsigned int len); 421 422 /* hooks.c */ 423 int fscrypt_file_open(struct inode *inode, struct file *filp); 424 int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, 425 struct dentry *dentry); 426 int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, 427 struct inode *new_dir, struct dentry *new_dentry, 428 unsigned int flags); 429 int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, 430 struct fscrypt_name *fname); 431 int fscrypt_prepare_lookup_partial(struct inode *dir, struct dentry *dentry); 432 int __fscrypt_prepare_readdir(struct inode *dir); 433 int __fscrypt_prepare_setattr(struct dentry *dentry, struct iattr *attr); 434 int fscrypt_prepare_setflags(struct inode *inode, 435 unsigned int oldflags, unsigned int flags); 436 int fscrypt_prepare_symlink(struct inode *dir, const char *target, 437 unsigned int len, unsigned int max_len, 438 struct fscrypt_str *disk_link); 439 int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, 440 unsigned int len, struct fscrypt_str *disk_link); 441 const char *fscrypt_get_symlink(struct inode *inode, const void *caddr, 442 unsigned int max_size, 443 struct delayed_call *done); 444 int fscrypt_symlink_getattr(const struct path *path, struct kstat *stat); 445 static inline void fscrypt_set_ops(struct super_block *sb, 446 const struct fscrypt_operations *s_cop) 447 { 448 sb->s_cop = s_cop; 449 } 450 #else /* !CONFIG_FS_ENCRYPTION */ 451 452 static inline struct fscrypt_inode_info * 453 fscrypt_get_inode_info(const struct inode *inode) 454 { 455 return NULL; 456 } 457 458 static inline bool fscrypt_needs_contents_encryption(const struct inode *inode) 459 { 460 return false; 461 } 462 463 static inline void fscrypt_handle_d_move(struct dentry *dentry) 464 { 465 } 466 467 static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) 468 { 469 return false; 470 } 471 472 static inline void fscrypt_prepare_dentry(struct dentry *dentry, 473 bool is_nokey_name) 474 { 475 } 476 477 /* crypto.c */ 478 static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work) 479 { 480 } 481 482 static inline struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, 483 unsigned int len, 484 unsigned int offs, 485 gfp_t gfp_flags) 486 { 487 return ERR_PTR(-EOPNOTSUPP); 488 } 489 490 static inline int fscrypt_encrypt_block_inplace(const struct inode *inode, 491 struct page *page, 492 unsigned int len, 493 unsigned int offs, u64 lblk_num, 494 gfp_t gfp_flags) 495 { 496 return -EOPNOTSUPP; 497 } 498 499 static inline int fscrypt_decrypt_pagecache_blocks(struct folio *folio, 500 size_t len, size_t offs) 501 { 502 return -EOPNOTSUPP; 503 } 504 505 static inline int fscrypt_decrypt_block_inplace(const struct inode *inode, 506 struct page *page, 507 unsigned int len, 508 unsigned int offs, u64 lblk_num) 509 { 510 return -EOPNOTSUPP; 511 } 512 513 static inline bool fscrypt_is_bounce_page(struct page *page) 514 { 515 return false; 516 } 517 518 static inline struct page *fscrypt_pagecache_page(struct page *bounce_page) 519 { 520 WARN_ON_ONCE(1); 521 return ERR_PTR(-EINVAL); 522 } 523 524 static inline bool fscrypt_is_bounce_folio(struct folio *folio) 525 { 526 return false; 527 } 528 529 static inline struct folio *fscrypt_pagecache_folio(struct folio *bounce_folio) 530 { 531 WARN_ON_ONCE(1); 532 return ERR_PTR(-EINVAL); 533 } 534 535 static inline void fscrypt_free_bounce_page(struct page *bounce_page) 536 { 537 } 538 539 /* policy.c */ 540 static inline int fscrypt_ioctl_set_policy(struct file *filp, 541 const void __user *arg) 542 { 543 return -EOPNOTSUPP; 544 } 545 546 static inline int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg) 547 { 548 return -EOPNOTSUPP; 549 } 550 551 static inline int fscrypt_ioctl_get_policy_ex(struct file *filp, 552 void __user *arg) 553 { 554 return -EOPNOTSUPP; 555 } 556 557 static inline int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg) 558 { 559 return -EOPNOTSUPP; 560 } 561 562 static inline int fscrypt_has_permitted_context(struct inode *parent, 563 struct inode *child) 564 { 565 return 0; 566 } 567 568 static inline int fscrypt_set_context(struct inode *inode, void *fs_data) 569 { 570 return -EOPNOTSUPP; 571 } 572 573 struct fscrypt_dummy_policy { 574 }; 575 576 static inline int 577 fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param, 578 struct fscrypt_dummy_policy *dummy_policy) 579 { 580 return -EINVAL; 581 } 582 583 static inline bool 584 fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1, 585 const struct fscrypt_dummy_policy *p2) 586 { 587 return true; 588 } 589 590 static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq, 591 char sep, 592 struct super_block *sb) 593 { 594 } 595 596 static inline bool 597 fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy) 598 { 599 return false; 600 } 601 602 static inline void 603 fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy) 604 { 605 } 606 607 /* keyring.c */ 608 static inline void fscrypt_destroy_keyring(struct super_block *sb) 609 { 610 } 611 612 static inline int fscrypt_ioctl_add_key(struct file *filp, void __user *arg) 613 { 614 return -EOPNOTSUPP; 615 } 616 617 static inline int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg) 618 { 619 return -EOPNOTSUPP; 620 } 621 622 static inline int fscrypt_ioctl_remove_key_all_users(struct file *filp, 623 void __user *arg) 624 { 625 return -EOPNOTSUPP; 626 } 627 628 static inline int fscrypt_ioctl_get_key_status(struct file *filp, 629 void __user *arg) 630 { 631 return -EOPNOTSUPP; 632 } 633 634 /* keysetup.c */ 635 636 static inline int fscrypt_prepare_new_inode(struct inode *dir, 637 struct inode *inode, 638 bool *encrypt_ret) 639 { 640 if (IS_ENCRYPTED(dir)) 641 return -EOPNOTSUPP; 642 return 0; 643 } 644 645 static inline void fscrypt_put_encryption_info(struct inode *inode) 646 { 647 return; 648 } 649 650 static inline void fscrypt_free_inode(struct inode *inode) 651 { 652 } 653 654 static inline int fscrypt_drop_inode(struct inode *inode) 655 { 656 return 0; 657 } 658 659 /* fname.c */ 660 static inline int fscrypt_setup_filename(struct inode *dir, 661 const struct qstr *iname, 662 int lookup, struct fscrypt_name *fname) 663 { 664 if (IS_ENCRYPTED(dir)) 665 return -EOPNOTSUPP; 666 667 memset(fname, 0, sizeof(*fname)); 668 fname->usr_fname = iname; 669 fname->disk_name.name = (unsigned char *)iname->name; 670 fname->disk_name.len = iname->len; 671 return 0; 672 } 673 674 static inline void fscrypt_free_filename(struct fscrypt_name *fname) 675 { 676 return; 677 } 678 679 static inline int fscrypt_fname_alloc_buffer(u32 max_encrypted_len, 680 struct fscrypt_str *crypto_str) 681 { 682 return -EOPNOTSUPP; 683 } 684 685 static inline void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str) 686 { 687 return; 688 } 689 690 static inline int fscrypt_fname_disk_to_usr(const struct inode *inode, 691 u32 hash, u32 minor_hash, 692 const struct fscrypt_str *iname, 693 struct fscrypt_str *oname) 694 { 695 return -EOPNOTSUPP; 696 } 697 698 static inline bool fscrypt_match_name(const struct fscrypt_name *fname, 699 const u8 *de_name, u32 de_name_len) 700 { 701 /* Encryption support disabled; use standard comparison */ 702 if (de_name_len != fname->disk_name.len) 703 return false; 704 return !memcmp(de_name, fname->disk_name.name, fname->disk_name.len); 705 } 706 707 static inline u64 fscrypt_fname_siphash(const struct inode *dir, 708 const struct qstr *name) 709 { 710 WARN_ON_ONCE(1); 711 return 0; 712 } 713 714 static inline int fscrypt_d_revalidate(struct dentry *dentry, 715 unsigned int flags) 716 { 717 return 1; 718 } 719 720 /* bio.c */ 721 static inline bool fscrypt_decrypt_bio(struct bio *bio) 722 { 723 return true; 724 } 725 726 static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, 727 sector_t pblk, unsigned int len) 728 { 729 return -EOPNOTSUPP; 730 } 731 732 /* hooks.c */ 733 734 static inline int fscrypt_file_open(struct inode *inode, struct file *filp) 735 { 736 if (IS_ENCRYPTED(inode)) 737 return -EOPNOTSUPP; 738 return 0; 739 } 740 741 static inline int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, 742 struct dentry *dentry) 743 { 744 return -EOPNOTSUPP; 745 } 746 747 static inline int __fscrypt_prepare_rename(struct inode *old_dir, 748 struct dentry *old_dentry, 749 struct inode *new_dir, 750 struct dentry *new_dentry, 751 unsigned int flags) 752 { 753 return -EOPNOTSUPP; 754 } 755 756 static inline int __fscrypt_prepare_lookup(struct inode *dir, 757 struct dentry *dentry, 758 struct fscrypt_name *fname) 759 { 760 return -EOPNOTSUPP; 761 } 762 763 static inline int fscrypt_prepare_lookup_partial(struct inode *dir, 764 struct dentry *dentry) 765 { 766 return -EOPNOTSUPP; 767 } 768 769 static inline int __fscrypt_prepare_readdir(struct inode *dir) 770 { 771 return -EOPNOTSUPP; 772 } 773 774 static inline int __fscrypt_prepare_setattr(struct dentry *dentry, 775 struct iattr *attr) 776 { 777 return -EOPNOTSUPP; 778 } 779 780 static inline int fscrypt_prepare_setflags(struct inode *inode, 781 unsigned int oldflags, 782 unsigned int flags) 783 { 784 return 0; 785 } 786 787 static inline int fscrypt_prepare_symlink(struct inode *dir, 788 const char *target, 789 unsigned int len, 790 unsigned int max_len, 791 struct fscrypt_str *disk_link) 792 { 793 if (IS_ENCRYPTED(dir)) 794 return -EOPNOTSUPP; 795 disk_link->name = (unsigned char *)target; 796 disk_link->len = len + 1; 797 if (disk_link->len > max_len) 798 return -ENAMETOOLONG; 799 return 0; 800 } 801 802 static inline int __fscrypt_encrypt_symlink(struct inode *inode, 803 const char *target, 804 unsigned int len, 805 struct fscrypt_str *disk_link) 806 { 807 return -EOPNOTSUPP; 808 } 809 810 static inline const char *fscrypt_get_symlink(struct inode *inode, 811 const void *caddr, 812 unsigned int max_size, 813 struct delayed_call *done) 814 { 815 return ERR_PTR(-EOPNOTSUPP); 816 } 817 818 static inline int fscrypt_symlink_getattr(const struct path *path, 819 struct kstat *stat) 820 { 821 return -EOPNOTSUPP; 822 } 823 824 static inline void fscrypt_set_ops(struct super_block *sb, 825 const struct fscrypt_operations *s_cop) 826 { 827 } 828 829 #endif /* !CONFIG_FS_ENCRYPTION */ 830 831 /* inline_crypt.c */ 832 #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT 833 834 bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode); 835 836 void fscrypt_set_bio_crypt_ctx(struct bio *bio, 837 const struct inode *inode, u64 first_lblk, 838 gfp_t gfp_mask); 839 840 void fscrypt_set_bio_crypt_ctx_bh(struct bio *bio, 841 const struct buffer_head *first_bh, 842 gfp_t gfp_mask); 843 844 bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode, 845 u64 next_lblk); 846 847 bool fscrypt_mergeable_bio_bh(struct bio *bio, 848 const struct buffer_head *next_bh); 849 850 bool fscrypt_dio_supported(struct inode *inode); 851 852 u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, u64 nr_blocks); 853 854 #else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ 855 856 static inline bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode) 857 { 858 return false; 859 } 860 861 static inline void fscrypt_set_bio_crypt_ctx(struct bio *bio, 862 const struct inode *inode, 863 u64 first_lblk, gfp_t gfp_mask) { } 864 865 static inline void fscrypt_set_bio_crypt_ctx_bh( 866 struct bio *bio, 867 const struct buffer_head *first_bh, 868 gfp_t gfp_mask) { } 869 870 static inline bool fscrypt_mergeable_bio(struct bio *bio, 871 const struct inode *inode, 872 u64 next_lblk) 873 { 874 return true; 875 } 876 877 static inline bool fscrypt_mergeable_bio_bh(struct bio *bio, 878 const struct buffer_head *next_bh) 879 { 880 return true; 881 } 882 883 static inline bool fscrypt_dio_supported(struct inode *inode) 884 { 885 return !fscrypt_needs_contents_encryption(inode); 886 } 887 888 static inline u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, 889 u64 nr_blocks) 890 { 891 return nr_blocks; 892 } 893 #endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ 894 895 /** 896 * fscrypt_inode_uses_inline_crypto() - test whether an inode uses inline 897 * encryption 898 * @inode: an inode. If encrypted, its key must be set up. 899 * 900 * Return: true if the inode requires file contents encryption and if the 901 * encryption should be done in the block layer via blk-crypto rather 902 * than in the filesystem layer. 903 */ 904 static inline bool fscrypt_inode_uses_inline_crypto(const struct inode *inode) 905 { 906 return fscrypt_needs_contents_encryption(inode) && 907 __fscrypt_inode_uses_inline_crypto(inode); 908 } 909 910 /** 911 * fscrypt_inode_uses_fs_layer_crypto() - test whether an inode uses fs-layer 912 * encryption 913 * @inode: an inode. If encrypted, its key must be set up. 914 * 915 * Return: true if the inode requires file contents encryption and if the 916 * encryption should be done in the filesystem layer rather than in the 917 * block layer via blk-crypto. 918 */ 919 static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode) 920 { 921 return fscrypt_needs_contents_encryption(inode) && 922 !__fscrypt_inode_uses_inline_crypto(inode); 923 } 924 925 /** 926 * fscrypt_has_encryption_key() - check whether an inode has had its key set up 927 * @inode: the inode to check 928 * 929 * Return: %true if the inode has had its encryption key set up, else %false. 930 * 931 * Usually this should be preceded by fscrypt_get_encryption_info() to try to 932 * set up the key first. 933 */ 934 static inline bool fscrypt_has_encryption_key(const struct inode *inode) 935 { 936 return fscrypt_get_inode_info(inode) != NULL; 937 } 938 939 /** 940 * fscrypt_prepare_link() - prepare to link an inode into a possibly-encrypted 941 * directory 942 * @old_dentry: an existing dentry for the inode being linked 943 * @dir: the target directory 944 * @dentry: negative dentry for the target filename 945 * 946 * A new link can only be added to an encrypted directory if the directory's 947 * encryption key is available --- since otherwise we'd have no way to encrypt 948 * the filename. 949 * 950 * We also verify that the link will not violate the constraint that all files 951 * in an encrypted directory tree use the same encryption policy. 952 * 953 * Return: 0 on success, -ENOKEY if the directory's encryption key is missing, 954 * -EXDEV if the link would result in an inconsistent encryption policy, or 955 * another -errno code. 956 */ 957 static inline int fscrypt_prepare_link(struct dentry *old_dentry, 958 struct inode *dir, 959 struct dentry *dentry) 960 { 961 if (IS_ENCRYPTED(dir)) 962 return __fscrypt_prepare_link(d_inode(old_dentry), dir, dentry); 963 return 0; 964 } 965 966 /** 967 * fscrypt_prepare_rename() - prepare for a rename between possibly-encrypted 968 * directories 969 * @old_dir: source directory 970 * @old_dentry: dentry for source file 971 * @new_dir: target directory 972 * @new_dentry: dentry for target location (may be negative unless exchanging) 973 * @flags: rename flags (we care at least about %RENAME_EXCHANGE) 974 * 975 * Prepare for ->rename() where the source and/or target directories may be 976 * encrypted. A new link can only be added to an encrypted directory if the 977 * directory's encryption key is available --- since otherwise we'd have no way 978 * to encrypt the filename. A rename to an existing name, on the other hand, 979 * *is* cryptographically possible without the key. However, we take the more 980 * conservative approach and just forbid all no-key renames. 981 * 982 * We also verify that the rename 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 an encryption key is missing, -EXDEV if the 986 * rename would cause inconsistent encryption policies, or another -errno code. 987 */ 988 static inline int fscrypt_prepare_rename(struct inode *old_dir, 989 struct dentry *old_dentry, 990 struct inode *new_dir, 991 struct dentry *new_dentry, 992 unsigned int flags) 993 { 994 if (IS_ENCRYPTED(old_dir) || IS_ENCRYPTED(new_dir)) 995 return __fscrypt_prepare_rename(old_dir, old_dentry, 996 new_dir, new_dentry, flags); 997 return 0; 998 } 999 1000 /** 1001 * fscrypt_prepare_lookup() - prepare to lookup a name in a possibly-encrypted 1002 * directory 1003 * @dir: directory being searched 1004 * @dentry: filename being looked up 1005 * @fname: (output) the name to use to search the on-disk directory 1006 * 1007 * Prepare for ->lookup() in a directory which may be encrypted by determining 1008 * the name that will actually be used to search the directory on-disk. If the 1009 * directory's encryption policy is supported by this kernel and its encryption 1010 * key is available, then the lookup is assumed to be by plaintext name; 1011 * otherwise, it is assumed to be by no-key name. 1012 * 1013 * This will set DCACHE_NOKEY_NAME on the dentry if the lookup is by no-key 1014 * name. In this case the filesystem must assign the dentry a dentry_operations 1015 * which contains fscrypt_d_revalidate (or contains a d_revalidate method that 1016 * calls fscrypt_d_revalidate), so that the dentry will be invalidated if the 1017 * directory's encryption key is later added. 1018 * 1019 * Return: 0 on success; -ENOENT if the directory's key is unavailable but the 1020 * filename isn't a valid no-key name, so a negative dentry should be created; 1021 * or another -errno code. 1022 */ 1023 static inline int fscrypt_prepare_lookup(struct inode *dir, 1024 struct dentry *dentry, 1025 struct fscrypt_name *fname) 1026 { 1027 if (IS_ENCRYPTED(dir)) 1028 return __fscrypt_prepare_lookup(dir, dentry, fname); 1029 1030 memset(fname, 0, sizeof(*fname)); 1031 fname->usr_fname = &dentry->d_name; 1032 fname->disk_name.name = (unsigned char *)dentry->d_name.name; 1033 fname->disk_name.len = dentry->d_name.len; 1034 1035 fscrypt_prepare_dentry(dentry, false); 1036 1037 return 0; 1038 } 1039 1040 /** 1041 * fscrypt_prepare_readdir() - prepare to read a possibly-encrypted directory 1042 * @dir: the directory inode 1043 * 1044 * If the directory is encrypted and it doesn't already have its encryption key 1045 * set up, try to set it up so that the filenames will be listed in plaintext 1046 * form rather than in no-key form. 1047 * 1048 * Return: 0 on success; -errno on error. Note that the encryption key being 1049 * unavailable is not considered an error. It is also not an error if 1050 * the encryption policy is unsupported by this kernel; that is treated 1051 * like the key being unavailable, so that files can still be deleted. 1052 */ 1053 static inline int fscrypt_prepare_readdir(struct inode *dir) 1054 { 1055 if (IS_ENCRYPTED(dir)) 1056 return __fscrypt_prepare_readdir(dir); 1057 return 0; 1058 } 1059 1060 /** 1061 * fscrypt_prepare_setattr() - prepare to change a possibly-encrypted inode's 1062 * attributes 1063 * @dentry: dentry through which the inode is being changed 1064 * @attr: attributes to change 1065 * 1066 * Prepare for ->setattr() on a possibly-encrypted inode. On an encrypted file, 1067 * most attribute changes are allowed even without the encryption key. However, 1068 * without the encryption key we do have to forbid truncates. This is needed 1069 * because the size being truncated to may not be a multiple of the filesystem 1070 * block size, and in that case we'd have to decrypt the final block, zero the 1071 * portion past i_size, and re-encrypt it. (We *could* allow truncating to a 1072 * filesystem block boundary, but it's simpler to just forbid all truncates --- 1073 * and we already forbid all other contents modifications without the key.) 1074 * 1075 * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code 1076 * if a problem occurred while setting up the encryption key. 1077 */ 1078 static inline int fscrypt_prepare_setattr(struct dentry *dentry, 1079 struct iattr *attr) 1080 { 1081 if (IS_ENCRYPTED(d_inode(dentry))) 1082 return __fscrypt_prepare_setattr(dentry, attr); 1083 return 0; 1084 } 1085 1086 /** 1087 * fscrypt_encrypt_symlink() - encrypt the symlink target if needed 1088 * @inode: symlink inode 1089 * @target: plaintext symlink target 1090 * @len: length of @target excluding null terminator 1091 * @disk_link: (in/out) the on-disk symlink target being prepared 1092 * 1093 * If the symlink target needs to be encrypted, then this function encrypts it 1094 * into @disk_link->name. fscrypt_prepare_symlink() must have been called 1095 * previously to compute @disk_link->len. If the filesystem did not allocate a 1096 * buffer for @disk_link->name after calling fscrypt_prepare_link(), then one 1097 * will be kmalloc()'ed and the filesystem will be responsible for freeing it. 1098 * 1099 * Return: 0 on success, -errno on failure 1100 */ 1101 static inline int fscrypt_encrypt_symlink(struct inode *inode, 1102 const char *target, 1103 unsigned int len, 1104 struct fscrypt_str *disk_link) 1105 { 1106 if (IS_ENCRYPTED(inode)) 1107 return __fscrypt_encrypt_symlink(inode, target, len, disk_link); 1108 return 0; 1109 } 1110 1111 /* If *pagep is a bounce page, free it and set *pagep to the pagecache page */ 1112 static inline void fscrypt_finalize_bounce_page(struct page **pagep) 1113 { 1114 struct page *page = *pagep; 1115 1116 if (fscrypt_is_bounce_page(page)) { 1117 *pagep = fscrypt_pagecache_page(page); 1118 fscrypt_free_bounce_page(page); 1119 } 1120 } 1121 1122 #endif /* _LINUX_FSCRYPT_H */ 1123