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 inode *dir, const struct qstr *name, 196 struct dentry *dentry, unsigned int flags); 197 198 static inline struct fscrypt_inode_info * 199 fscrypt_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 */ 221 static 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 */ 234 static 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 */ 276 static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) 277 { 278 return dentry->d_flags & DCACHE_NOKEY_NAME; 279 } 280 281 static 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(&dentry->d_lock); 294 dentry->d_flags |= DCACHE_NOKEY_NAME; 295 spin_unlock(&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(&dentry->d_lock); 305 dentry->d_flags &= ~DCACHE_OP_REVALIDATE; 306 spin_unlock(&dentry->d_lock); 307 } 308 } 309 310 /* crypto.c */ 311 void fscrypt_enqueue_decrypt_work(struct work_struct *); 312 313 struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, 314 unsigned int len, 315 unsigned int offs, 316 gfp_t gfp_flags); 317 int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page, 318 unsigned int len, unsigned int offs, 319 u64 lblk_num, gfp_t gfp_flags); 320 321 int fscrypt_decrypt_pagecache_blocks(struct folio *folio, size_t len, 322 size_t offs); 323 int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page, 324 unsigned int len, unsigned int offs, 325 u64 lblk_num); 326 327 static inline bool fscrypt_is_bounce_page(struct page *page) 328 { 329 return page->mapping == NULL; 330 } 331 332 static inline struct page *fscrypt_pagecache_page(struct page *bounce_page) 333 { 334 return (struct page *)page_private(bounce_page); 335 } 336 337 static inline bool fscrypt_is_bounce_folio(struct folio *folio) 338 { 339 return folio->mapping == NULL; 340 } 341 342 static inline struct folio *fscrypt_pagecache_folio(struct folio *bounce_folio) 343 { 344 return bounce_folio->private; 345 } 346 347 void fscrypt_free_bounce_page(struct page *bounce_page); 348 349 /* policy.c */ 350 int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg); 351 int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg); 352 int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *arg); 353 int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg); 354 int fscrypt_has_permitted_context(struct inode *parent, struct inode *child); 355 int fscrypt_context_for_new_inode(void *ctx, struct inode *inode); 356 int fscrypt_set_context(struct inode *inode, void *fs_data); 357 358 struct fscrypt_dummy_policy { 359 const union fscrypt_policy *policy; 360 }; 361 362 int fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param, 363 struct fscrypt_dummy_policy *dummy_policy); 364 bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1, 365 const struct fscrypt_dummy_policy *p2); 366 void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep, 367 struct super_block *sb); 368 static inline bool 369 fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy) 370 { 371 return dummy_policy->policy != NULL; 372 } 373 static inline void 374 fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy) 375 { 376 kfree(dummy_policy->policy); 377 dummy_policy->policy = NULL; 378 } 379 380 /* keyring.c */ 381 void fscrypt_destroy_keyring(struct super_block *sb); 382 int fscrypt_ioctl_add_key(struct file *filp, void __user *arg); 383 int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg); 384 int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *arg); 385 int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg); 386 387 /* keysetup.c */ 388 int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode, 389 bool *encrypt_ret); 390 void fscrypt_put_encryption_info(struct inode *inode); 391 void fscrypt_free_inode(struct inode *inode); 392 int fscrypt_drop_inode(struct inode *inode); 393 394 /* fname.c */ 395 int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname, 396 u8 *out, unsigned int olen); 397 bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len, 398 u32 max_len, u32 *encrypted_len_ret); 399 int fscrypt_setup_filename(struct inode *inode, const struct qstr *iname, 400 int lookup, struct fscrypt_name *fname); 401 402 static inline void fscrypt_free_filename(struct fscrypt_name *fname) 403 { 404 kfree(fname->crypto_buf.name); 405 } 406 407 int fscrypt_fname_alloc_buffer(u32 max_encrypted_len, 408 struct fscrypt_str *crypto_str); 409 void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str); 410 int fscrypt_fname_disk_to_usr(const struct inode *inode, 411 u32 hash, u32 minor_hash, 412 const struct fscrypt_str *iname, 413 struct fscrypt_str *oname); 414 bool fscrypt_match_name(const struct fscrypt_name *fname, 415 const u8 *de_name, u32 de_name_len); 416 u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name); 417 418 /* bio.c */ 419 bool fscrypt_decrypt_bio(struct bio *bio); 420 int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, 421 sector_t pblk, unsigned int len); 422 423 /* hooks.c */ 424 int fscrypt_file_open(struct inode *inode, struct file *filp); 425 int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, 426 struct dentry *dentry); 427 int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, 428 struct inode *new_dir, struct dentry *new_dentry, 429 unsigned int flags); 430 int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, 431 struct fscrypt_name *fname); 432 int fscrypt_prepare_lookup_partial(struct inode *dir, struct dentry *dentry); 433 int __fscrypt_prepare_readdir(struct inode *dir); 434 int __fscrypt_prepare_setattr(struct dentry *dentry, struct iattr *attr); 435 int fscrypt_prepare_setflags(struct inode *inode, 436 unsigned int oldflags, unsigned int flags); 437 int fscrypt_prepare_symlink(struct inode *dir, const char *target, 438 unsigned int len, unsigned int max_len, 439 struct fscrypt_str *disk_link); 440 int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, 441 unsigned int len, struct fscrypt_str *disk_link); 442 const char *fscrypt_get_symlink(struct inode *inode, const void *caddr, 443 unsigned int max_size, 444 struct delayed_call *done); 445 int fscrypt_symlink_getattr(const struct path *path, struct kstat *stat); 446 static inline void fscrypt_set_ops(struct super_block *sb, 447 const struct fscrypt_operations *s_cop) 448 { 449 sb->s_cop = s_cop; 450 } 451 #else /* !CONFIG_FS_ENCRYPTION */ 452 453 static inline struct fscrypt_inode_info * 454 fscrypt_get_inode_info(const struct inode *inode) 455 { 456 return NULL; 457 } 458 459 static inline bool fscrypt_needs_contents_encryption(const struct inode *inode) 460 { 461 return false; 462 } 463 464 static inline void fscrypt_handle_d_move(struct dentry *dentry) 465 { 466 } 467 468 static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) 469 { 470 return false; 471 } 472 473 static inline void fscrypt_prepare_dentry(struct dentry *dentry, 474 bool is_nokey_name) 475 { 476 } 477 478 /* crypto.c */ 479 static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work) 480 { 481 } 482 483 static inline struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, 484 unsigned int len, 485 unsigned int offs, 486 gfp_t gfp_flags) 487 { 488 return ERR_PTR(-EOPNOTSUPP); 489 } 490 491 static inline int fscrypt_encrypt_block_inplace(const struct inode *inode, 492 struct page *page, 493 unsigned int len, 494 unsigned int offs, u64 lblk_num, 495 gfp_t gfp_flags) 496 { 497 return -EOPNOTSUPP; 498 } 499 500 static inline int fscrypt_decrypt_pagecache_blocks(struct folio *folio, 501 size_t len, size_t offs) 502 { 503 return -EOPNOTSUPP; 504 } 505 506 static inline int fscrypt_decrypt_block_inplace(const struct inode *inode, 507 struct page *page, 508 unsigned int len, 509 unsigned int offs, u64 lblk_num) 510 { 511 return -EOPNOTSUPP; 512 } 513 514 static inline bool fscrypt_is_bounce_page(struct page *page) 515 { 516 return false; 517 } 518 519 static inline struct page *fscrypt_pagecache_page(struct page *bounce_page) 520 { 521 WARN_ON_ONCE(1); 522 return ERR_PTR(-EINVAL); 523 } 524 525 static inline bool fscrypt_is_bounce_folio(struct folio *folio) 526 { 527 return false; 528 } 529 530 static inline struct folio *fscrypt_pagecache_folio(struct folio *bounce_folio) 531 { 532 WARN_ON_ONCE(1); 533 return ERR_PTR(-EINVAL); 534 } 535 536 static inline void fscrypt_free_bounce_page(struct page *bounce_page) 537 { 538 } 539 540 /* policy.c */ 541 static inline int fscrypt_ioctl_set_policy(struct file *filp, 542 const void __user *arg) 543 { 544 return -EOPNOTSUPP; 545 } 546 547 static inline int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg) 548 { 549 return -EOPNOTSUPP; 550 } 551 552 static inline int fscrypt_ioctl_get_policy_ex(struct file *filp, 553 void __user *arg) 554 { 555 return -EOPNOTSUPP; 556 } 557 558 static inline int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg) 559 { 560 return -EOPNOTSUPP; 561 } 562 563 static inline int fscrypt_has_permitted_context(struct inode *parent, 564 struct inode *child) 565 { 566 return 0; 567 } 568 569 static inline int fscrypt_set_context(struct inode *inode, void *fs_data) 570 { 571 return -EOPNOTSUPP; 572 } 573 574 struct fscrypt_dummy_policy { 575 }; 576 577 static inline int 578 fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param, 579 struct fscrypt_dummy_policy *dummy_policy) 580 { 581 return -EINVAL; 582 } 583 584 static inline bool 585 fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1, 586 const struct fscrypt_dummy_policy *p2) 587 { 588 return true; 589 } 590 591 static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq, 592 char sep, 593 struct super_block *sb) 594 { 595 } 596 597 static inline bool 598 fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy) 599 { 600 return false; 601 } 602 603 static inline void 604 fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy) 605 { 606 } 607 608 /* keyring.c */ 609 static inline void fscrypt_destroy_keyring(struct super_block *sb) 610 { 611 } 612 613 static inline int fscrypt_ioctl_add_key(struct file *filp, void __user *arg) 614 { 615 return -EOPNOTSUPP; 616 } 617 618 static inline int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg) 619 { 620 return -EOPNOTSUPP; 621 } 622 623 static inline int fscrypt_ioctl_remove_key_all_users(struct file *filp, 624 void __user *arg) 625 { 626 return -EOPNOTSUPP; 627 } 628 629 static inline int fscrypt_ioctl_get_key_status(struct file *filp, 630 void __user *arg) 631 { 632 return -EOPNOTSUPP; 633 } 634 635 /* keysetup.c */ 636 637 static inline int fscrypt_prepare_new_inode(struct inode *dir, 638 struct inode *inode, 639 bool *encrypt_ret) 640 { 641 if (IS_ENCRYPTED(dir)) 642 return -EOPNOTSUPP; 643 return 0; 644 } 645 646 static inline void fscrypt_put_encryption_info(struct inode *inode) 647 { 648 return; 649 } 650 651 static inline void fscrypt_free_inode(struct inode *inode) 652 { 653 } 654 655 static inline int fscrypt_drop_inode(struct inode *inode) 656 { 657 return 0; 658 } 659 660 /* fname.c */ 661 static inline int fscrypt_setup_filename(struct inode *dir, 662 const struct qstr *iname, 663 int lookup, struct fscrypt_name *fname) 664 { 665 if (IS_ENCRYPTED(dir)) 666 return -EOPNOTSUPP; 667 668 memset(fname, 0, sizeof(*fname)); 669 fname->usr_fname = iname; 670 fname->disk_name.name = (unsigned char *)iname->name; 671 fname->disk_name.len = iname->len; 672 return 0; 673 } 674 675 static inline void fscrypt_free_filename(struct fscrypt_name *fname) 676 { 677 return; 678 } 679 680 static inline int fscrypt_fname_alloc_buffer(u32 max_encrypted_len, 681 struct fscrypt_str *crypto_str) 682 { 683 return -EOPNOTSUPP; 684 } 685 686 static inline void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str) 687 { 688 return; 689 } 690 691 static inline int fscrypt_fname_disk_to_usr(const struct inode *inode, 692 u32 hash, u32 minor_hash, 693 const struct fscrypt_str *iname, 694 struct fscrypt_str *oname) 695 { 696 return -EOPNOTSUPP; 697 } 698 699 static inline bool fscrypt_match_name(const struct fscrypt_name *fname, 700 const u8 *de_name, u32 de_name_len) 701 { 702 /* Encryption support disabled; use standard comparison */ 703 if (de_name_len != fname->disk_name.len) 704 return false; 705 return !memcmp(de_name, fname->disk_name.name, fname->disk_name.len); 706 } 707 708 static inline u64 fscrypt_fname_siphash(const struct inode *dir, 709 const struct qstr *name) 710 { 711 WARN_ON_ONCE(1); 712 return 0; 713 } 714 715 static inline int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name, 716 struct dentry *dentry, unsigned int flags) 717 { 718 return 1; 719 } 720 721 /* bio.c */ 722 static inline bool fscrypt_decrypt_bio(struct bio *bio) 723 { 724 return true; 725 } 726 727 static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, 728 sector_t pblk, unsigned int len) 729 { 730 return -EOPNOTSUPP; 731 } 732 733 /* hooks.c */ 734 735 static inline int fscrypt_file_open(struct inode *inode, struct file *filp) 736 { 737 if (IS_ENCRYPTED(inode)) 738 return -EOPNOTSUPP; 739 return 0; 740 } 741 742 static inline int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, 743 struct dentry *dentry) 744 { 745 return -EOPNOTSUPP; 746 } 747 748 static inline int __fscrypt_prepare_rename(struct inode *old_dir, 749 struct dentry *old_dentry, 750 struct inode *new_dir, 751 struct dentry *new_dentry, 752 unsigned int flags) 753 { 754 return -EOPNOTSUPP; 755 } 756 757 static inline int __fscrypt_prepare_lookup(struct inode *dir, 758 struct dentry *dentry, 759 struct fscrypt_name *fname) 760 { 761 return -EOPNOTSUPP; 762 } 763 764 static inline int fscrypt_prepare_lookup_partial(struct inode *dir, 765 struct dentry *dentry) 766 { 767 return -EOPNOTSUPP; 768 } 769 770 static inline int __fscrypt_prepare_readdir(struct inode *dir) 771 { 772 return -EOPNOTSUPP; 773 } 774 775 static inline int __fscrypt_prepare_setattr(struct dentry *dentry, 776 struct iattr *attr) 777 { 778 return -EOPNOTSUPP; 779 } 780 781 static inline int fscrypt_prepare_setflags(struct inode *inode, 782 unsigned int oldflags, 783 unsigned int flags) 784 { 785 return 0; 786 } 787 788 static inline int fscrypt_prepare_symlink(struct inode *dir, 789 const char *target, 790 unsigned int len, 791 unsigned int max_len, 792 struct fscrypt_str *disk_link) 793 { 794 if (IS_ENCRYPTED(dir)) 795 return -EOPNOTSUPP; 796 disk_link->name = (unsigned char *)target; 797 disk_link->len = len + 1; 798 if (disk_link->len > max_len) 799 return -ENAMETOOLONG; 800 return 0; 801 } 802 803 static inline int __fscrypt_encrypt_symlink(struct inode *inode, 804 const char *target, 805 unsigned int len, 806 struct fscrypt_str *disk_link) 807 { 808 return -EOPNOTSUPP; 809 } 810 811 static inline const char *fscrypt_get_symlink(struct inode *inode, 812 const void *caddr, 813 unsigned int max_size, 814 struct delayed_call *done) 815 { 816 return ERR_PTR(-EOPNOTSUPP); 817 } 818 819 static inline int fscrypt_symlink_getattr(const struct path *path, 820 struct kstat *stat) 821 { 822 return -EOPNOTSUPP; 823 } 824 825 static inline void fscrypt_set_ops(struct super_block *sb, 826 const struct fscrypt_operations *s_cop) 827 { 828 } 829 830 #endif /* !CONFIG_FS_ENCRYPTION */ 831 832 /* inline_crypt.c */ 833 #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT 834 835 bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode); 836 837 void fscrypt_set_bio_crypt_ctx(struct bio *bio, 838 const struct inode *inode, u64 first_lblk, 839 gfp_t gfp_mask); 840 841 void fscrypt_set_bio_crypt_ctx_bh(struct bio *bio, 842 const struct buffer_head *first_bh, 843 gfp_t gfp_mask); 844 845 bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode, 846 u64 next_lblk); 847 848 bool fscrypt_mergeable_bio_bh(struct bio *bio, 849 const struct buffer_head *next_bh); 850 851 bool fscrypt_dio_supported(struct inode *inode); 852 853 u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, u64 nr_blocks); 854 855 #else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ 856 857 static inline bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode) 858 { 859 return false; 860 } 861 862 static inline void fscrypt_set_bio_crypt_ctx(struct bio *bio, 863 const struct inode *inode, 864 u64 first_lblk, gfp_t gfp_mask) { } 865 866 static inline void fscrypt_set_bio_crypt_ctx_bh( 867 struct bio *bio, 868 const struct buffer_head *first_bh, 869 gfp_t gfp_mask) { } 870 871 static inline bool fscrypt_mergeable_bio(struct bio *bio, 872 const struct inode *inode, 873 u64 next_lblk) 874 { 875 return true; 876 } 877 878 static inline bool fscrypt_mergeable_bio_bh(struct bio *bio, 879 const struct buffer_head *next_bh) 880 { 881 return true; 882 } 883 884 static inline bool fscrypt_dio_supported(struct inode *inode) 885 { 886 return !fscrypt_needs_contents_encryption(inode); 887 } 888 889 static inline u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, 890 u64 nr_blocks) 891 { 892 return nr_blocks; 893 } 894 #endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ 895 896 /** 897 * fscrypt_inode_uses_inline_crypto() - test whether an inode uses inline 898 * encryption 899 * @inode: an inode. If encrypted, its key must be set up. 900 * 901 * Return: true if the inode requires file contents encryption and if the 902 * encryption should be done in the block layer via blk-crypto rather 903 * than in the filesystem layer. 904 */ 905 static inline bool fscrypt_inode_uses_inline_crypto(const struct inode *inode) 906 { 907 return fscrypt_needs_contents_encryption(inode) && 908 __fscrypt_inode_uses_inline_crypto(inode); 909 } 910 911 /** 912 * fscrypt_inode_uses_fs_layer_crypto() - test whether an inode uses fs-layer 913 * encryption 914 * @inode: an inode. If encrypted, its key must be set up. 915 * 916 * Return: true if the inode requires file contents encryption and if the 917 * encryption should be done in the filesystem layer rather than in the 918 * block layer via blk-crypto. 919 */ 920 static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode) 921 { 922 return fscrypt_needs_contents_encryption(inode) && 923 !__fscrypt_inode_uses_inline_crypto(inode); 924 } 925 926 /** 927 * fscrypt_has_encryption_key() - check whether an inode has had its key set up 928 * @inode: the inode to check 929 * 930 * Return: %true if the inode has had its encryption key set up, else %false. 931 * 932 * Usually this should be preceded by fscrypt_get_encryption_info() to try to 933 * set up the key first. 934 */ 935 static inline bool fscrypt_has_encryption_key(const struct inode *inode) 936 { 937 return fscrypt_get_inode_info(inode) != NULL; 938 } 939 940 /** 941 * fscrypt_prepare_link() - prepare to link an inode into a possibly-encrypted 942 * directory 943 * @old_dentry: an existing dentry for the inode being linked 944 * @dir: the target directory 945 * @dentry: negative dentry for the target filename 946 * 947 * A new link can only be added to an encrypted directory if the directory's 948 * encryption key is available --- since otherwise we'd have no way to encrypt 949 * the filename. 950 * 951 * We also verify that the link will not violate the constraint that all files 952 * in an encrypted directory tree use the same encryption policy. 953 * 954 * Return: 0 on success, -ENOKEY if the directory's encryption key is missing, 955 * -EXDEV if the link would result in an inconsistent encryption policy, or 956 * another -errno code. 957 */ 958 static inline int fscrypt_prepare_link(struct dentry *old_dentry, 959 struct inode *dir, 960 struct dentry *dentry) 961 { 962 if (IS_ENCRYPTED(dir)) 963 return __fscrypt_prepare_link(d_inode(old_dentry), dir, dentry); 964 return 0; 965 } 966 967 /** 968 * fscrypt_prepare_rename() - prepare for a rename between possibly-encrypted 969 * directories 970 * @old_dir: source directory 971 * @old_dentry: dentry for source file 972 * @new_dir: target directory 973 * @new_dentry: dentry for target location (may be negative unless exchanging) 974 * @flags: rename flags (we care at least about %RENAME_EXCHANGE) 975 * 976 * Prepare for ->rename() where the source and/or target directories may be 977 * encrypted. A new link can only be added to an encrypted directory if the 978 * directory's encryption key is available --- since otherwise we'd have no way 979 * to encrypt the filename. A rename to an existing name, on the other hand, 980 * *is* cryptographically possible without the key. However, we take the more 981 * conservative approach and just forbid all no-key renames. 982 * 983 * We also verify that the rename will not violate the constraint that all files 984 * in an encrypted directory tree use the same encryption policy. 985 * 986 * Return: 0 on success, -ENOKEY if an encryption key is missing, -EXDEV if the 987 * rename would cause inconsistent encryption policies, or another -errno code. 988 */ 989 static inline int fscrypt_prepare_rename(struct inode *old_dir, 990 struct dentry *old_dentry, 991 struct inode *new_dir, 992 struct dentry *new_dentry, 993 unsigned int flags) 994 { 995 if (IS_ENCRYPTED(old_dir) || IS_ENCRYPTED(new_dir)) 996 return __fscrypt_prepare_rename(old_dir, old_dentry, 997 new_dir, new_dentry, flags); 998 return 0; 999 } 1000 1001 /** 1002 * fscrypt_prepare_lookup() - prepare to lookup a name in a possibly-encrypted 1003 * directory 1004 * @dir: directory being searched 1005 * @dentry: filename being looked up 1006 * @fname: (output) the name to use to search the on-disk directory 1007 * 1008 * Prepare for ->lookup() in a directory which may be encrypted by determining 1009 * the name that will actually be used to search the directory on-disk. If the 1010 * directory's encryption policy is supported by this kernel and its encryption 1011 * key is available, then the lookup is assumed to be by plaintext name; 1012 * otherwise, it is assumed to be by no-key name. 1013 * 1014 * This will set DCACHE_NOKEY_NAME on the dentry if the lookup is by no-key 1015 * name. In this case the filesystem must assign the dentry a dentry_operations 1016 * which contains fscrypt_d_revalidate (or contains a d_revalidate method that 1017 * calls fscrypt_d_revalidate), so that the dentry will be invalidated if the 1018 * directory's encryption key is later added. 1019 * 1020 * Return: 0 on success; -ENOENT if the directory's key is unavailable but the 1021 * filename isn't a valid no-key name, so a negative dentry should be created; 1022 * or another -errno code. 1023 */ 1024 static inline int fscrypt_prepare_lookup(struct inode *dir, 1025 struct dentry *dentry, 1026 struct fscrypt_name *fname) 1027 { 1028 if (IS_ENCRYPTED(dir)) 1029 return __fscrypt_prepare_lookup(dir, dentry, fname); 1030 1031 memset(fname, 0, sizeof(*fname)); 1032 fname->usr_fname = &dentry->d_name; 1033 fname->disk_name.name = (unsigned char *)dentry->d_name.name; 1034 fname->disk_name.len = dentry->d_name.len; 1035 1036 fscrypt_prepare_dentry(dentry, false); 1037 1038 return 0; 1039 } 1040 1041 /** 1042 * fscrypt_prepare_readdir() - prepare to read a possibly-encrypted directory 1043 * @dir: the directory inode 1044 * 1045 * If the directory is encrypted and it doesn't already have its encryption key 1046 * set up, try to set it up so that the filenames will be listed in plaintext 1047 * form rather than in no-key form. 1048 * 1049 * Return: 0 on success; -errno on error. Note that the encryption key being 1050 * unavailable is not considered an error. It is also not an error if 1051 * the encryption policy is unsupported by this kernel; that is treated 1052 * like the key being unavailable, so that files can still be deleted. 1053 */ 1054 static inline int fscrypt_prepare_readdir(struct inode *dir) 1055 { 1056 if (IS_ENCRYPTED(dir)) 1057 return __fscrypt_prepare_readdir(dir); 1058 return 0; 1059 } 1060 1061 /** 1062 * fscrypt_prepare_setattr() - prepare to change a possibly-encrypted inode's 1063 * attributes 1064 * @dentry: dentry through which the inode is being changed 1065 * @attr: attributes to change 1066 * 1067 * Prepare for ->setattr() on a possibly-encrypted inode. On an encrypted file, 1068 * most attribute changes are allowed even without the encryption key. However, 1069 * without the encryption key we do have to forbid truncates. This is needed 1070 * because the size being truncated to may not be a multiple of the filesystem 1071 * block size, and in that case we'd have to decrypt the final block, zero the 1072 * portion past i_size, and re-encrypt it. (We *could* allow truncating to a 1073 * filesystem block boundary, but it's simpler to just forbid all truncates --- 1074 * and we already forbid all other contents modifications without the key.) 1075 * 1076 * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code 1077 * if a problem occurred while setting up the encryption key. 1078 */ 1079 static inline int fscrypt_prepare_setattr(struct dentry *dentry, 1080 struct iattr *attr) 1081 { 1082 if (IS_ENCRYPTED(d_inode(dentry))) 1083 return __fscrypt_prepare_setattr(dentry, attr); 1084 return 0; 1085 } 1086 1087 /** 1088 * fscrypt_encrypt_symlink() - encrypt the symlink target if needed 1089 * @inode: symlink inode 1090 * @target: plaintext symlink target 1091 * @len: length of @target excluding null terminator 1092 * @disk_link: (in/out) the on-disk symlink target being prepared 1093 * 1094 * If the symlink target needs to be encrypted, then this function encrypts it 1095 * into @disk_link->name. fscrypt_prepare_symlink() must have been called 1096 * previously to compute @disk_link->len. If the filesystem did not allocate a 1097 * buffer for @disk_link->name after calling fscrypt_prepare_link(), then one 1098 * will be kmalloc()'ed and the filesystem will be responsible for freeing it. 1099 * 1100 * Return: 0 on success, -errno on failure 1101 */ 1102 static inline int fscrypt_encrypt_symlink(struct inode *inode, 1103 const char *target, 1104 unsigned int len, 1105 struct fscrypt_str *disk_link) 1106 { 1107 if (IS_ENCRYPTED(inode)) 1108 return __fscrypt_encrypt_symlink(inode, target, len, disk_link); 1109 return 0; 1110 } 1111 1112 /* If *pagep is a bounce page, free it and set *pagep to the pagecache page */ 1113 static inline void fscrypt_finalize_bounce_page(struct page **pagep) 1114 { 1115 struct page *page = *pagep; 1116 1117 if (fscrypt_is_bounce_page(page)) { 1118 *pagep = fscrypt_pagecache_page(page); 1119 fscrypt_free_bounce_page(page); 1120 } 1121 } 1122 1123 #endif /* _LINUX_FSCRYPT_H */ 1124