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7c1a000d | 1 | // SPDX-License-Identifier: GPL-2.0 |
0a8165d7 | 2 | /* |
6b4ea016 JK |
3 | * fs/f2fs/hash.c |
4 | * | |
5 | * Copyright (c) 2012 Samsung Electronics Co., Ltd. | |
6 | * http://www.samsung.com/ | |
7 | * | |
8 | * Portions of this code from linux/fs/ext3/hash.c | |
9 | * | |
10 | * Copyright (C) 2002 by Theodore Ts'o | |
6b4ea016 JK |
11 | */ |
12 | #include <linux/types.h> | |
13 | #include <linux/fs.h> | |
14 | #include <linux/f2fs_fs.h> | |
15 | #include <linux/cryptohash.h> | |
16 | #include <linux/pagemap.h> | |
17 | ||
18 | #include "f2fs.h" | |
19 | ||
20 | /* | |
21 | * Hashing code copied from ext3 | |
22 | */ | |
23 | #define DELTA 0x9E3779B9 | |
24 | ||
25 | static void TEA_transform(unsigned int buf[4], unsigned int const in[]) | |
26 | { | |
27 | __u32 sum = 0; | |
28 | __u32 b0 = buf[0], b1 = buf[1]; | |
29 | __u32 a = in[0], b = in[1], c = in[2], d = in[3]; | |
30 | int n = 16; | |
31 | ||
32 | do { | |
33 | sum += DELTA; | |
34 | b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b); | |
35 | b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d); | |
36 | } while (--n); | |
37 | ||
38 | buf[0] += b0; | |
39 | buf[1] += b1; | |
40 | } | |
41 | ||
3304b564 JK |
42 | static void str2hashbuf(const unsigned char *msg, size_t len, |
43 | unsigned int *buf, int num) | |
6b4ea016 JK |
44 | { |
45 | unsigned pad, val; | |
46 | int i; | |
47 | ||
48 | pad = (__u32)len | ((__u32)len << 8); | |
49 | pad |= pad << 16; | |
50 | ||
51 | val = pad; | |
52 | if (len > num * 4) | |
53 | len = num * 4; | |
54 | for (i = 0; i < len; i++) { | |
55 | if ((i % 4) == 0) | |
56 | val = pad; | |
57 | val = msg[i] + (val << 8); | |
58 | if ((i % 4) == 3) { | |
59 | *buf++ = val; | |
60 | val = pad; | |
61 | num--; | |
62 | } | |
63 | } | |
64 | if (--num >= 0) | |
65 | *buf++ = val; | |
66 | while (--num >= 0) | |
67 | *buf++ = pad; | |
68 | } | |
69 | ||
6332cd32 JK |
70 | f2fs_hash_t f2fs_dentry_hash(const struct qstr *name_info, |
71 | struct fscrypt_name *fname) | |
6b4ea016 | 72 | { |
2b50638d | 73 | __u32 hash; |
6b4ea016 | 74 | f2fs_hash_t f2fs_hash; |
3304b564 | 75 | const unsigned char *p; |
6b4ea016 | 76 | __u32 in[8], buf[4]; |
3304b564 | 77 | const unsigned char *name = name_info->name; |
eee6160f | 78 | size_t len = name_info->len; |
6b4ea016 | 79 | |
6332cd32 JK |
80 | /* encrypted bigname case */ |
81 | if (fname && !fname->disk_name.name) | |
82 | return cpu_to_le32(fname->hash); | |
83 | ||
eaa693f4 | 84 | if (is_dot_dotdot(name_info)) |
38e0abdc NJ |
85 | return 0; |
86 | ||
6b4ea016 JK |
87 | /* Initialize the default seed for the hash checksum functions */ |
88 | buf[0] = 0x67452301; | |
89 | buf[1] = 0xefcdab89; | |
90 | buf[2] = 0x98badcfe; | |
91 | buf[3] = 0x10325476; | |
92 | ||
93 | p = name; | |
9836b8b9 | 94 | while (1) { |
6b4ea016 JK |
95 | str2hashbuf(p, len, in, 4); |
96 | TEA_transform(buf, in); | |
6b4ea016 | 97 | p += 16; |
9836b8b9 LR |
98 | if (len <= 16) |
99 | break; | |
100 | len -= 16; | |
6b4ea016 JK |
101 | } |
102 | hash = buf[0]; | |
25ca923b | 103 | f2fs_hash = cpu_to_le32(hash & ~F2FS_HASH_COL_BIT); |
6b4ea016 JK |
104 | return f2fs_hash; |
105 | } |