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