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1/* SPDX-License-Identifier: GPL-2.0-only */2/*3 * This file is part of UBIFS.4 *5 * Copyright (C) 2006-2008 Nokia Corporation.6 *7 * Authors: Artem Bityutskiy (Битюцкий Артём)8 * Adrian Hunter9 */10 11/*12 * This header contains various key-related definitions and helper function.13 * UBIFS allows several key schemes, so we access key fields only via these14 * helpers. At the moment only one key scheme is supported.15 *16 * Simple key scheme17 * ~~~~~~~~~~~~~~~~~18 *19 * Keys are 64-bits long. First 32-bits are inode number (parent inode number20 * in case of direntry key). Next 3 bits are node type. The last 29 bits are21 * 4KiB offset in case of inode node, and direntry hash in case of a direntry22 * node. We use "r5" hash borrowed from reiserfs.23 */24 25/*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 of28 * different c->key_format. But right now, there is only one key type, UBIFS_SIMPLE_KEY_FMT.29 */30 31#ifndef __UBIFS_KEY_H__32#define __UBIFS_KEY_H__33 34/**35 * key_mask_hash - mask a valid hash value.36 * @val: value to be masked37 *38 * We use hash values as offset in directories, so values %0 and %1 are39 * reserved for "." and "..". %2 is reserved for "end of readdir" marker. This40 * function makes sure the reserved values are not used.41 */42static inline uint32_t key_mask_hash(uint32_t hash)43{44 hash &= UBIFS_S_KEY_HASH_MASK;45 if (unlikely(hash <= 2))46 hash += 3;47 return hash;48}49 50/**51 * key_r5_hash - R5 hash function (borrowed from reiserfs).52 * @s: direntry name53 * @len: name length54 */55static inline uint32_t key_r5_hash(const char *s, int len)56{57 uint32_t a = 0;58 const signed char *str = (const signed char *)s;59 60 while (len--) {61 a += *str << 4;62 a += *str >> 4;63 a *= 11;64 str++;65 }66 67 return key_mask_hash(a);68}69 70/**71 * key_test_hash - testing hash function.72 * @str: direntry name73 * @len: name length74 */75static inline uint32_t key_test_hash(const char *str, int len)76{77 uint32_t a = 0;78 79 len = min_t(uint32_t, len, 4);80 memcpy(&a, str, len);81 return key_mask_hash(a);82}83 84/**85 * ino_key_init - initialize inode key.86 * @c: UBIFS file-system description object87 * @key: key to initialize88 * @inum: inode number89 */90static inline void ino_key_init(const struct ubifs_info *c,91 union ubifs_key *key, ino_t inum)92{93 key->u32[0] = inum;94 key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS;95}96 97/**98 * ino_key_init_flash - initialize on-flash inode key.99 * @c: UBIFS file-system description object100 * @k: key to initialize101 * @inum: inode number102 */103static inline void ino_key_init_flash(const struct ubifs_info *c, void *k,104 ino_t inum)105{106 union ubifs_key *key = k;107 108 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);111}112 113/**114 * lowest_ino_key - get the lowest possible inode key.115 * @c: UBIFS file-system description object116 * @key: key to initialize117 * @inum: inode number118 */119static inline void lowest_ino_key(const struct ubifs_info *c,120 union ubifs_key *key, ino_t inum)121{122 key->u32[0] = inum;123 key->u32[1] = 0;124}125 126/**127 * highest_ino_key - get the highest possible inode key.128 * @c: UBIFS file-system description object129 * @key: key to initialize130 * @inum: inode number131 */132static inline void highest_ino_key(const struct ubifs_info *c,133 union ubifs_key *key, ino_t inum)134{135 key->u32[0] = inum;136 key->u32[1] = 0xffffffff;137}138 139/**140 * dent_key_init - initialize directory entry key.141 * @c: UBIFS file-system description object142 * @key: key to initialize143 * @inum: parent inode number144 * @nm: direntry name and length. Not a string when encrypted!145 */146static inline void dent_key_init(const struct ubifs_info *c,147 union ubifs_key *key, ino_t inum,148 const struct fscrypt_name *nm)149{150 uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));151 152 ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));153 key->u32[0] = inum;154 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);155}156 157/**158 * dent_key_init_hash - initialize directory entry key without re-calculating159 * hash function.160 * @c: UBIFS file-system description object161 * @key: key to initialize162 * @inum: parent inode number163 * @hash: direntry name hash164 */165static inline void dent_key_init_hash(const struct ubifs_info *c,166 union ubifs_key *key, ino_t inum,167 uint32_t hash)168{169 ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));170 key->u32[0] = inum;171 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);172}173 174/**175 * dent_key_init_flash - initialize on-flash directory entry key.176 * @c: UBIFS file-system description object177 * @k: key to initialize178 * @inum: parent inode number179 * @nm: direntry name and length180 */181static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,182 ino_t inum,183 const struct fscrypt_name *nm)184{185 union ubifs_key *key = k;186 uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));187 188 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);193}194 195/**196 * lowest_dent_key - get the lowest possible directory entry key.197 * @c: UBIFS file-system description object198 * @key: where to store the lowest key199 * @inum: parent inode number200 */201static inline void lowest_dent_key(const struct ubifs_info *c,202 union ubifs_key *key, ino_t inum)203{204 key->u32[0] = inum;205 key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS;206}207 208/**209 * xent_key_init - initialize extended attribute entry key.210 * @c: UBIFS file-system description object211 * @key: key to initialize212 * @inum: host inode number213 * @nm: extended attribute entry name and length214 */215static inline void xent_key_init(const struct ubifs_info *c,216 union ubifs_key *key, ino_t inum,217 const struct fscrypt_name *nm)218{219 uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));220 221 ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));222 key->u32[0] = inum;223 key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);224}225 226/**227 * xent_key_init_flash - initialize on-flash extended attribute entry key.228 * @c: UBIFS file-system description object229 * @k: key to initialize230 * @inum: host inode number231 * @nm: extended attribute entry name and length232 */233static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,234 ino_t inum, const struct fscrypt_name *nm)235{236 union ubifs_key *key = k;237 uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));238 239 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);244}245 246/**247 * lowest_xent_key - get the lowest possible extended attribute entry key.248 * @c: UBIFS file-system description object249 * @key: where to store the lowest key250 * @inum: host inode number251 */252static inline void lowest_xent_key(const struct ubifs_info *c,253 union ubifs_key *key, ino_t inum)254{255 key->u32[0] = inum;256 key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;257}258 259/**260 * data_key_init - initialize data key.261 * @c: UBIFS file-system description object262 * @key: key to initialize263 * @inum: inode number264 * @block: block number265 */266static inline void data_key_init(const struct ubifs_info *c,267 union ubifs_key *key, ino_t inum,268 unsigned int block)269{270 ubifs_assert(c, !(block & ~UBIFS_S_KEY_BLOCK_MASK));271 key->u32[0] = inum;272 key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS);273}274 275/**276 * highest_data_key - get the highest possible data key for an inode.277 * @c: UBIFS file-system description object278 * @key: key to initialize279 * @inum: inode number280 */281static inline void highest_data_key(const struct ubifs_info *c,282 union ubifs_key *key, ino_t inum)283{284 data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK);285}286 287/**288 * trun_key_init - initialize truncation node key.289 * @c: UBIFS file-system description object290 * @key: key to initialize291 * @inum: inode number292 *293 * Note, UBIFS does not have truncation keys on the media and this function is294 * only used for purposes of replay.295 */296static inline void trun_key_init(const struct ubifs_info *c,297 union ubifs_key *key, ino_t inum)298{299 key->u32[0] = inum;300 key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;301}302 303/**304 * invalid_key_init - initialize invalid node key.305 * @c: UBIFS file-system description object306 * @key: key to initialize307 *308 * This is a helper function which marks a @key object as invalid.309 */310static inline void invalid_key_init(const struct ubifs_info *c,311 union ubifs_key *key)312{313 key->u32[0] = 0xDEADBEAF;314 key->u32[1] = UBIFS_INVALID_KEY;315}316 317/**318 * key_type - get key type.319 * @c: UBIFS file-system description object320 * @key: key to get type of321 */322static inline int key_type(const struct ubifs_info *c,323 const union ubifs_key *key)324{325 return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;326}327 328/**329 * key_type_flash - get type of a on-flash formatted key.330 * @c: UBIFS file-system description object331 * @k: key to get type of332 */333static inline int key_type_flash(const struct ubifs_info *c, const void *k)334{335 const union ubifs_key *key = k;336 337 return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;338}339 340/**341 * key_inum - fetch inode number from key.342 * @c: UBIFS file-system description object343 * @k: key to fetch inode number from344 */345static inline ino_t key_inum(const struct ubifs_info *c, const void *k)346{347 const union ubifs_key *key = k;348 349 return key->u32[0];350}351 352/**353 * key_inum_flash - fetch inode number from an on-flash formatted key.354 * @c: UBIFS file-system description object355 * @k: key to fetch inode number from356 */357static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)358{359 const union ubifs_key *key = k;360 361 return le32_to_cpu(key->j32[0]);362}363 364/**365 * key_hash - get directory entry hash.366 * @c: UBIFS file-system description object367 * @key: the key to get hash from368 */369static inline uint32_t key_hash(const struct ubifs_info *c,370 const union ubifs_key *key)371{372 return key->u32[1] & UBIFS_S_KEY_HASH_MASK;373}374 375/**376 * key_hash_flash - get directory entry hash from an on-flash formatted key.377 * @c: UBIFS file-system description object378 * @k: the key to get hash from379 */380static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)381{382 const union ubifs_key *key = k;383 384 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;385}386 387/**388 * key_block - get data block number.389 * @c: UBIFS file-system description object390 * @key: the key to get the block number from391 */392static inline unsigned int key_block(const struct ubifs_info *c,393 const union ubifs_key *key)394{395 return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;396}397 398/**399 * key_block_flash - get data block number from an on-flash formatted key.400 * @c: UBIFS file-system description object401 * @k: the key to get the block number from402 */403static inline unsigned int key_block_flash(const struct ubifs_info *c,404 const void *k)405{406 const union ubifs_key *key = k;407 408 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK;409}410 411/**412 * key_read - transform a key to in-memory format.413 * @c: UBIFS file-system description object414 * @from: the key to transform415 * @to: the key to store the result416 */417static inline void key_read(const struct ubifs_info *c, const void *from,418 union ubifs_key *to)419{420 const union ubifs_key *f = from;421 422 to->u32[0] = le32_to_cpu(f->j32[0]);423 to->u32[1] = le32_to_cpu(f->j32[1]);424}425 426/**427 * key_write - transform a key from in-memory format.428 * @c: UBIFS file-system description object429 * @from: the key to transform430 * @to: the key to store the result431 */432static inline void key_write(const struct ubifs_info *c,433 const union ubifs_key *from, void *to)434{435 union ubifs_key *t = to;436 437 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);440}441 442/**443 * key_write_idx - transform a key from in-memory format for the index.444 * @c: UBIFS file-system description object445 * @from: the key to transform446 * @to: the key to store the result447 */448static inline void key_write_idx(const struct ubifs_info *c,449 const union ubifs_key *from, void *to)450{451 union ubifs_key *t = to;452 453 t->j32[0] = cpu_to_le32(from->u32[0]);454 t->j32[1] = cpu_to_le32(from->u32[1]);455}456 457/**458 * key_copy - copy a key.459 * @c: UBIFS file-system description object460 * @from: the key to copy from461 * @to: the key to copy to462 */463static inline void key_copy(const struct ubifs_info *c,464 const union ubifs_key *from, union ubifs_key *to)465{466 to->u64[0] = from->u64[0];467}468 469/**470 * keys_cmp - compare keys.471 * @c: UBIFS file-system description object472 * @key1: the first key to compare473 * @key2: the second key to compare474 *475 * This function compares 2 keys and returns %-1 if @key1 is less than476 * @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2.477 */478static inline int keys_cmp(const struct ubifs_info *c,479 const union ubifs_key *key1,480 const union ubifs_key *key2)481{482 if (key1->u32[0] < key2->u32[0])483 return -1;484 if (key1->u32[0] > key2->u32[0])485 return 1;486 if (key1->u32[1] < key2->u32[1])487 return -1;488 if (key1->u32[1] > key2->u32[1])489 return 1;490 491 return 0;492}493 494/**495 * keys_eq - determine if keys are equivalent.496 * @c: UBIFS file-system description object497 * @key1: the first key to compare498 * @key2: the second key to compare499 *500 * This function compares 2 keys and returns %1 if @key1 is equal to @key2 and501 * %0 if not.502 */503static inline int keys_eq(const struct ubifs_info *c,504 const union ubifs_key *key1,505 const union ubifs_key *key2)506{507 if (key1->u32[0] != key2->u32[0])508 return 0;509 if (key1->u32[1] != key2->u32[1])510 return 0;511 return 1;512}513 514/**515 * is_hash_key - is a key vulnerable to hash collisions.516 * @c: UBIFS file-system description object517 * @key: key518 *519 * This function returns %1 if @key is a hashed key or %0 otherwise.520 */521static inline int is_hash_key(const struct ubifs_info *c,522 const union ubifs_key *key)523{524 int type = key_type(c, key);525 526 return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY;527}528 529/**530 * key_max_inode_size - get maximum file size allowed by current key format.531 * @c: UBIFS file-system description object532 */533static inline unsigned long long key_max_inode_size(const struct ubifs_info *c)534{535 switch (c->key_fmt) {536 case UBIFS_SIMPLE_KEY_FMT:537 return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE;538 default:539 return 0;540 }541}542 543#endif /* !__UBIFS_KEY_H__ */544