1 /* SPDX-License-Identifier: GPL-2.0-only */
3 * This file is part of UBIFS.
5 * Copyright (C) 2006-2008 Nokia Corporation.
7 * Authors: Artem Bityutskiy (Битюцкий Артём)
12 * This header contains various key-related definitions and helper function.
13 * UBIFS allows several key schemes, so we access key fields only via these
14 * helpers. At the moment only one key scheme is supported.
19 * Keys are 64-bits long. First 32-bits are inode number (parent inode number
20 * in case of direntry key). Next 3 bits are node type. The last 29 bits are
21 * 4KiB offset in case of inode node, and direntry hash in case of a direntry
22 * node. We use "r5" hash borrowed from reiserfs.
26 * Lot's of the key helpers require a struct ubifs_info *c as the first parameter.
27 * But we are not using it at all currently. That's designed for future extensions of
28 * different c->key_format. But right now, there is only one key type, UBIFS_SIMPLE_KEY_FMT.
31 #ifndef __UBIFS_KEY_H__
32 #define __UBIFS_KEY_H__
35 * key_mask_hash - mask a valid hash value.
36 * @val: value to be masked
38 * We use hash values as offset in directories, so values %0 and %1 are
39 * reserved for "." and "..". %2 is reserved for "end of readdir" marker. This
40 * function makes sure the reserved values are not used.
42 static inline uint32_t key_mask_hash(uint32_t hash)
44 hash &= UBIFS_S_KEY_HASH_MASK;
45 if (unlikely(hash <= 2))
51 * key_r5_hash - R5 hash function (borrowed from reiserfs).
55 static inline uint32_t key_r5_hash(const char *s, int len)
58 const signed char *str = (const signed char *)s;
67 return key_mask_hash(a);
71 * key_test_hash - testing hash function.
75 static inline uint32_t key_test_hash(const char *str, int len)
79 len = min_t(uint32_t, len, 4);
81 return key_mask_hash(a);
85 * ino_key_init - initialize inode key.
86 * @c: UBIFS file-system description object
87 * @key: key to initialize
90 static inline void ino_key_init(const struct ubifs_info *c,
91 union ubifs_key *key, ino_t inum)
94 key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS;
98 * ino_key_init_flash - initialize on-flash inode key.
99 * @c: UBIFS file-system description object
100 * @k: key to initialize
101 * @inum: inode number
103 static inline void ino_key_init_flash(const struct ubifs_info *c, void *k,
106 union ubifs_key *key = k;
108 key->j32[0] = cpu_to_le32(inum);
109 key->j32[1] = cpu_to_le32(UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS);
110 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
114 * lowest_ino_key - get the lowest possible inode key.
115 * @c: UBIFS file-system description object
116 * @key: key to initialize
117 * @inum: inode number
119 static inline void lowest_ino_key(const struct ubifs_info *c,
120 union ubifs_key *key, ino_t inum)
127 * highest_ino_key - get the highest possible inode key.
128 * @c: UBIFS file-system description object
129 * @key: key to initialize
130 * @inum: inode number
132 static inline void highest_ino_key(const struct ubifs_info *c,
133 union ubifs_key *key, ino_t inum)
136 key->u32[1] = 0xffffffff;
140 * dent_key_init - initialize directory entry key.
141 * @c: UBIFS file-system description object
142 * @key: key to initialize
143 * @inum: parent inode number
144 * @nm: direntry name and length. Not a string when encrypted!
146 static inline void dent_key_init(const struct ubifs_info *c,
147 union ubifs_key *key, ino_t inum,
148 const struct fscrypt_name *nm)
150 uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
152 ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
154 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
158 * dent_key_init_hash - initialize directory entry key without re-calculating
160 * @c: UBIFS file-system description object
161 * @key: key to initialize
162 * @inum: parent inode number
163 * @hash: direntry name hash
165 static inline void dent_key_init_hash(const struct ubifs_info *c,
166 union ubifs_key *key, ino_t inum,
169 ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
171 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
175 * dent_key_init_flash - initialize on-flash directory entry key.
176 * @c: UBIFS file-system description object
177 * @k: key to initialize
178 * @inum: parent inode number
179 * @nm: direntry name and length
181 static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,
183 const struct fscrypt_name *nm)
185 union ubifs_key *key = k;
186 uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
188 ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
189 key->j32[0] = cpu_to_le32(inum);
190 key->j32[1] = cpu_to_le32(hash |
191 (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS));
192 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
196 * lowest_dent_key - get the lowest possible directory entry key.
197 * @c: UBIFS file-system description object
198 * @key: where to store the lowest key
199 * @inum: parent inode number
201 static inline void lowest_dent_key(const struct ubifs_info *c,
202 union ubifs_key *key, ino_t inum)
205 key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS;
209 * xent_key_init - initialize extended attribute entry key.
210 * @c: UBIFS file-system description object
211 * @key: key to initialize
212 * @inum: host inode number
213 * @nm: extended attribute entry name and length
215 static inline void xent_key_init(const struct ubifs_info *c,
216 union ubifs_key *key, ino_t inum,
217 const struct fscrypt_name *nm)
219 uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
221 ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
223 key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
227 * xent_key_init_flash - initialize on-flash extended attribute entry key.
228 * @c: UBIFS file-system description object
229 * @k: key to initialize
230 * @inum: host inode number
231 * @nm: extended attribute entry name and length
233 static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
234 ino_t inum, const struct fscrypt_name *nm)
236 union ubifs_key *key = k;
237 uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
239 ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
240 key->j32[0] = cpu_to_le32(inum);
241 key->j32[1] = cpu_to_le32(hash |
242 (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS));
243 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
247 * lowest_xent_key - get the lowest possible extended attribute entry key.
248 * @c: UBIFS file-system description object
249 * @key: where to store the lowest key
250 * @inum: host inode number
252 static inline void lowest_xent_key(const struct ubifs_info *c,
253 union ubifs_key *key, ino_t inum)
256 key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;
260 * data_key_init - initialize data key.
261 * @c: UBIFS file-system description object
262 * @key: key to initialize
263 * @inum: inode number
264 * @block: block number
266 static inline void data_key_init(const struct ubifs_info *c,
267 union ubifs_key *key, ino_t inum,
270 ubifs_assert(c, !(block & ~UBIFS_S_KEY_BLOCK_MASK));
272 key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS);
276 * highest_data_key - get the highest possible data key for an inode.
277 * @c: UBIFS file-system description object
278 * @key: key to initialize
279 * @inum: inode number
281 static inline void highest_data_key(const struct ubifs_info *c,
282 union ubifs_key *key, ino_t inum)
284 data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK);
288 * trun_key_init - initialize truncation node key.
289 * @c: UBIFS file-system description object
290 * @key: key to initialize
291 * @inum: inode number
293 * Note, UBIFS does not have truncation keys on the media and this function is
294 * only used for purposes of replay.
296 static inline void trun_key_init(const struct ubifs_info *c,
297 union ubifs_key *key, ino_t inum)
300 key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;
304 * invalid_key_init - initialize invalid node key.
305 * @c: UBIFS file-system description object
306 * @key: key to initialize
308 * This is a helper function which marks a @key object as invalid.
310 static inline void invalid_key_init(const struct ubifs_info *c,
311 union ubifs_key *key)
313 key->u32[0] = 0xDEADBEAF;
314 key->u32[1] = UBIFS_INVALID_KEY;
318 * key_type - get key type.
319 * @c: UBIFS file-system description object
320 * @key: key to get type of
322 static inline int key_type(const struct ubifs_info *c,
323 const union ubifs_key *key)
325 return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;
329 * key_type_flash - get type of a on-flash formatted key.
330 * @c: UBIFS file-system description object
331 * @k: key to get type of
333 static inline int key_type_flash(const struct ubifs_info *c, const void *k)
335 const union ubifs_key *key = k;
337 return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
341 * key_inum - fetch inode number from key.
342 * @c: UBIFS file-system description object
343 * @k: key to fetch inode number from
345 static inline ino_t key_inum(const struct ubifs_info *c, const void *k)
347 const union ubifs_key *key = k;
353 * key_inum_flash - fetch inode number from an on-flash formatted key.
354 * @c: UBIFS file-system description object
355 * @k: key to fetch inode number from
357 static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)
359 const union ubifs_key *key = k;
361 return le32_to_cpu(key->j32[0]);
365 * key_hash - get directory entry hash.
366 * @c: UBIFS file-system description object
367 * @key: the key to get hash from
369 static inline uint32_t key_hash(const struct ubifs_info *c,
370 const union ubifs_key *key)
372 return key->u32[1] & UBIFS_S_KEY_HASH_MASK;
376 * key_hash_flash - get directory entry hash from an on-flash formatted key.
377 * @c: UBIFS file-system description object
378 * @k: the key to get hash from
380 static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)
382 const union ubifs_key *key = k;
384 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;
388 * key_block - get data block number.
389 * @c: UBIFS file-system description object
390 * @key: the key to get the block number from
392 static inline unsigned int key_block(const struct ubifs_info *c,
393 const union ubifs_key *key)
395 return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;
399 * key_block_flash - get data block number from an on-flash formatted key.
400 * @c: UBIFS file-system description object
401 * @k: the key to get the block number from
403 static inline unsigned int key_block_flash(const struct ubifs_info *c,
406 const union ubifs_key *key = k;
408 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK;
412 * key_read - transform a key to in-memory format.
413 * @c: UBIFS file-system description object
414 * @from: the key to transform
415 * @to: the key to store the result
417 static inline void key_read(const struct ubifs_info *c, const void *from,
420 const union ubifs_key *f = from;
422 to->u32[0] = le32_to_cpu(f->j32[0]);
423 to->u32[1] = le32_to_cpu(f->j32[1]);
427 * key_write - transform a key from in-memory format.
428 * @c: UBIFS file-system description object
429 * @from: the key to transform
430 * @to: the key to store the result
432 static inline void key_write(const struct ubifs_info *c,
433 const union ubifs_key *from, void *to)
435 union ubifs_key *t = to;
437 t->j32[0] = cpu_to_le32(from->u32[0]);
438 t->j32[1] = cpu_to_le32(from->u32[1]);
439 memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8);
443 * key_write_idx - transform a key from in-memory format for the index.
444 * @c: UBIFS file-system description object
445 * @from: the key to transform
446 * @to: the key to store the result
448 static inline void key_write_idx(const struct ubifs_info *c,
449 const union ubifs_key *from, void *to)
451 union ubifs_key *t = to;
453 t->j32[0] = cpu_to_le32(from->u32[0]);
454 t->j32[1] = cpu_to_le32(from->u32[1]);
458 * key_copy - copy a key.
459 * @c: UBIFS file-system description object
460 * @from: the key to copy from
461 * @to: the key to copy to
463 static inline void key_copy(const struct ubifs_info *c,
464 const union ubifs_key *from, union ubifs_key *to)
466 to->u64[0] = from->u64[0];
470 * keys_cmp - compare keys.
471 * @c: UBIFS file-system description object
472 * @key1: the first key to compare
473 * @key2: the second key to compare
475 * This function compares 2 keys and returns %-1 if @key1 is less than
476 * @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2.
478 static inline int keys_cmp(const struct ubifs_info *c,
479 const union ubifs_key *key1,
480 const union ubifs_key *key2)
482 if (key1->u32[0] < key2->u32[0])
484 if (key1->u32[0] > key2->u32[0])
486 if (key1->u32[1] < key2->u32[1])
488 if (key1->u32[1] > key2->u32[1])
495 * keys_eq - determine if keys are equivalent.
496 * @c: UBIFS file-system description object
497 * @key1: the first key to compare
498 * @key2: the second key to compare
500 * This function compares 2 keys and returns %1 if @key1 is equal to @key2 and
503 static inline int keys_eq(const struct ubifs_info *c,
504 const union ubifs_key *key1,
505 const union ubifs_key *key2)
507 if (key1->u32[0] != key2->u32[0])
509 if (key1->u32[1] != key2->u32[1])
515 * is_hash_key - is a key vulnerable to hash collisions.
516 * @c: UBIFS file-system description object
519 * This function returns %1 if @key is a hashed key or %0 otherwise.
521 static inline int is_hash_key(const struct ubifs_info *c,
522 const union ubifs_key *key)
524 int type = key_type(c, key);
526 return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY;
530 * key_max_inode_size - get maximum file size allowed by current key format.
531 * @c: UBIFS file-system description object
533 static inline unsigned long long key_max_inode_size(const struct ubifs_info *c)
535 switch (c->key_fmt) {
536 case UBIFS_SIMPLE_KEY_FMT:
537 return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE;
543 #endif /* !__UBIFS_KEY_H__ */