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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/pagemap.h>
16#include <linux/unicode.h>
17
18#include "f2fs.h"
19
20/*
21 * Hashing code copied from ext3
22 */
23#define DELTA 0x9E3779B9
24
25static 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
42static void str2hashbuf(const unsigned char *msg, size_t len,
43 unsigned int *buf, int num)
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
70static u32 TEA_hash_name(const u8 *p, size_t len)
71{
72 __u32 in[8], buf[4];
73
74 /* Initialize the default seed for the hash checksum functions */
75 buf[0] = 0x67452301;
76 buf[1] = 0xefcdab89;
77 buf[2] = 0x98badcfe;
78 buf[3] = 0x10325476;
79
80 while (1) {
81 str2hashbuf(p, len, in, 4);
82 TEA_transform(buf, in);
83 p += 16;
84 if (len <= 16)
85 break;
86 len -= 16;
87 }
88 return buf[0] & ~F2FS_HASH_COL_BIT;
89}
90
91/*
92 * Compute @fname->hash. For all directories, @fname->disk_name must be set.
93 * For casefolded directories, @fname->usr_fname must be set, and also
94 * @fname->cf_name if the filename is valid Unicode.
95 */
96void f2fs_hash_filename(const struct inode *dir, struct f2fs_filename *fname)
97{
98 const u8 *name = fname->disk_name.name;
99 size_t len = fname->disk_name.len;
100
101 WARN_ON_ONCE(!name);
102
103 if (is_dot_dotdot(name, len)) {
104 fname->hash = 0;
105 return;
106 }
107
108#ifdef CONFIG_UNICODE
109 if (IS_CASEFOLDED(dir)) {
110 /*
111 * If the casefolded name is provided, hash it instead of the
112 * on-disk name. If the casefolded name is *not* provided, that
113 * should only be because the name wasn't valid Unicode, so fall
114 * back to treating the name as an opaque byte sequence. Note
115 * that to handle encrypted directories, the fallback must use
116 * usr_fname (plaintext) rather than disk_name (ciphertext).
117 */
118 WARN_ON_ONCE(!fname->usr_fname->name);
119 if (fname->cf_name.name) {
120 name = fname->cf_name.name;
121 len = fname->cf_name.len;
122 } else {
123 name = fname->usr_fname->name;
124 len = fname->usr_fname->len;
125 }
126 if (IS_ENCRYPTED(dir)) {
127 struct qstr tmp = QSTR_INIT(name, len);
128
129 fname->hash =
130 cpu_to_le32(fscrypt_fname_siphash(dir, &tmp));
131 return;
132 }
133 }
134#endif
135 fname->hash = cpu_to_le32(TEA_hash_name(name, len));
136}
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
26static 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
43static 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
71static 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
108f2fs_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
137opaque_seq:
138#endif
139 return __f2fs_dentry_hash(name_info, fname);
140}