1 // SPDX-License-Identifier: GPL-2.0
2 /*
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
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 #include <linux/unicode.h>
18
19 #include "f2fs.h"
20
21 /*
22 * Hashing code copied from ext3
23 */
24 #define DELTA 0x9E3779B9
25
TEA_transform(unsigned int buf[4],unsigned int const in[])26 static void TEA_transform(unsigned int buf[4], unsigned int const in[])
27 {
28 __u32 sum = 0;
29 __u32 b0 = buf[0], b1 = buf[1];
30 __u32 a = in[0], b = in[1], c = in[2], d = in[3];
31 int n = 16;
32
33 do {
34 sum += DELTA;
35 b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
36 b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
37 } while (--n);
38
39 buf[0] += b0;
40 buf[1] += b1;
41 }
42
str2hashbuf(const unsigned char * msg,size_t len,unsigned int * buf,int num)43 static void str2hashbuf(const unsigned char *msg, size_t len,
44 unsigned int *buf, int num)
45 {
46 unsigned pad, val;
47 int i;
48
49 pad = (__u32)len | ((__u32)len << 8);
50 pad |= pad << 16;
51
52 val = pad;
53 if (len > num * 4)
54 len = num * 4;
55 for (i = 0; i < len; i++) {
56 if ((i % 4) == 0)
57 val = pad;
58 val = msg[i] + (val << 8);
59 if ((i % 4) == 3) {
60 *buf++ = val;
61 val = pad;
62 num--;
63 }
64 }
65 if (--num >= 0)
66 *buf++ = val;
67 while (--num >= 0)
68 *buf++ = pad;
69 }
70
__f2fs_dentry_hash(const struct qstr * name_info,struct fscrypt_name * fname)71 static f2fs_hash_t __f2fs_dentry_hash(const struct qstr *name_info,
72 struct fscrypt_name *fname)
73 {
74 __u32 hash;
75 f2fs_hash_t f2fs_hash;
76 const unsigned char *p;
77 __u32 in[8], buf[4];
78 const unsigned char *name = name_info->name;
79 size_t len = name_info->len;
80
81 /* encrypted bigname case */
82 if (fname && !fname->disk_name.name)
83 return cpu_to_le32(fname->hash);
84
85 if (is_dot_dotdot(name_info))
86 return 0;
87
88 /* Initialize the default seed for the hash checksum functions */
89 buf[0] = 0x67452301;
90 buf[1] = 0xefcdab89;
91 buf[2] = 0x98badcfe;
92 buf[3] = 0x10325476;
93
94 p = name;
95 while (1) {
96 str2hashbuf(p, len, in, 4);
97 TEA_transform(buf, in);
98 p += 16;
99 if (len <= 16)
100 break;
101 len -= 16;
102 }
103 hash = buf[0];
104 f2fs_hash = cpu_to_le32(hash & ~F2FS_HASH_COL_BIT);
105 return f2fs_hash;
106 }
107
f2fs_dentry_hash(const struct inode * dir,const struct qstr * name_info,struct fscrypt_name * fname)108 f2fs_hash_t f2fs_dentry_hash(const struct inode *dir,
109 const struct qstr *name_info, struct fscrypt_name *fname)
110 {
111 #ifdef CONFIG_UNICODE
112 struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
113 const struct unicode_map *um = sbi->s_encoding;
114 int r, dlen;
115 unsigned char *buff;
116 struct qstr folded;
117
118 if (!name_info->len || !IS_CASEFOLDED(dir))
119 goto opaque_seq;
120
121 buff = f2fs_kzalloc(sbi, sizeof(char) * PATH_MAX, GFP_KERNEL);
122 if (!buff)
123 return -ENOMEM;
124
125 dlen = utf8_casefold(um, name_info, buff, PATH_MAX);
126 if (dlen < 0) {
127 kvfree(buff);
128 goto opaque_seq;
129 }
130 folded.name = buff;
131 folded.len = dlen;
132 r = __f2fs_dentry_hash(&folded, fname);
133
134 kvfree(buff);
135 return r;
136
137 opaque_seq:
138 #endif
139 return __f2fs_dentry_hash(name_info, fname);
140 }
141
