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1/*
2 * linux/fs/ext4/hash.c
3 *
4 * Copyright (C) 2002 by Theodore Ts'o
5 *
6 * This file is released under the GPL v2.
7 *
8 * This file may be redistributed under the terms of the GNU Public
9 * License.
10 */
11
12#include <linux/fs.h>
13#include <linux/cryptohash.h>
14#include "ext4.h"
15
16#define DELTA 0x9E3779B9
17
18static void TEA_transform(__u32 buf[4], __u32 const in[])
19{
20 __u32 sum = 0;
21 __u32 b0 = buf[0], b1 = buf[1];
22 __u32 a = in[0], b = in[1], c = in[2], d = in[3];
23 int n = 16;
24
25 do {
26 sum += DELTA;
27 b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
28 b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
29 } while (--n);
30
31 buf[0] += b0;
32 buf[1] += b1;
33}
34
35
36/* The old legacy hash */
37static __u32 dx_hack_hash_unsigned(const char *name, int len)
38{
39 __u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
40 const unsigned char *ucp = (const unsigned char *) name;
41
42 while (len--) {
43 hash = hash1 + (hash0 ^ (((int) *ucp++) * 7152373));
44
45 if (hash & 0x80000000)
46 hash -= 0x7fffffff;
47 hash1 = hash0;
48 hash0 = hash;
49 }
50 return hash0 << 1;
51}
52
53static __u32 dx_hack_hash_signed(const char *name, int len)
54{
55 __u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
56 const signed char *scp = (const signed char *) name;
57
58 while (len--) {
59 hash = hash1 + (hash0 ^ (((int) *scp++) * 7152373));
60
61 if (hash & 0x80000000)
62 hash -= 0x7fffffff;
63 hash1 = hash0;
64 hash0 = hash;
65 }
66 return hash0 << 1;
67}
68
69static void str2hashbuf_signed(const char *msg, int len, __u32 *buf, int num)
70{
71 __u32 pad, val;
72 int i;
73 const signed char *scp = (const signed char *) msg;
74
75 pad = (__u32)len | ((__u32)len << 8);
76 pad |= pad << 16;
77
78 val = pad;
79 if (len > num*4)
80 len = num * 4;
81 for (i = 0; i < len; i++) {
82 if ((i % 4) == 0)
83 val = pad;
84 val = ((int) scp[i]) + (val << 8);
85 if ((i % 4) == 3) {
86 *buf++ = val;
87 val = pad;
88 num--;
89 }
90 }
91 if (--num >= 0)
92 *buf++ = val;
93 while (--num >= 0)
94 *buf++ = pad;
95}
96
97static void str2hashbuf_unsigned(const char *msg, int len, __u32 *buf, int num)
98{
99 __u32 pad, val;
100 int i;
101 const unsigned char *ucp = (const unsigned char *) msg;
102
103 pad = (__u32)len | ((__u32)len << 8);
104 pad |= pad << 16;
105
106 val = pad;
107 if (len > num*4)
108 len = num * 4;
109 for (i = 0; i < len; i++) {
110 if ((i % 4) == 0)
111 val = pad;
112 val = ((int) ucp[i]) + (val << 8);
113 if ((i % 4) == 3) {
114 *buf++ = val;
115 val = pad;
116 num--;
117 }
118 }
119 if (--num >= 0)
120 *buf++ = val;
121 while (--num >= 0)
122 *buf++ = pad;
123}
124
125/*
126 * Returns the hash of a filename. If len is 0 and name is NULL, then
127 * this function can be used to test whether or not a hash version is
128 * supported.
129 *
130 * The seed is an 4 longword (32 bits) "secret" which can be used to
131 * uniquify a hash. If the seed is all zero's, then some default seed
132 * may be used.
133 *
134 * A particular hash version specifies whether or not the seed is
135 * represented, and whether or not the returned hash is 32 bits or 64
136 * bits. 32 bit hashes will return 0 for the minor hash.
137 */
138int ext4fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo)
139{
140 __u32 hash;
141 __u32 minor_hash = 0;
142 const char *p;
143 int i;
144 __u32 in[8], buf[4];
145 void (*str2hashbuf)(const char *, int, __u32 *, int) =
146 str2hashbuf_signed;
147
148 /* Initialize the default seed for the hash checksum functions */
149 buf[0] = 0x67452301;
150 buf[1] = 0xefcdab89;
151 buf[2] = 0x98badcfe;
152 buf[3] = 0x10325476;
153
154 /* Check to see if the seed is all zero's */
155 if (hinfo->seed) {
156 for (i = 0; i < 4; i++) {
157 if (hinfo->seed[i]) {
158 memcpy(buf, hinfo->seed, sizeof(buf));
159 break;
160 }
161 }
162 }
163
164 switch (hinfo->hash_version) {
165 case DX_HASH_LEGACY_UNSIGNED:
166 hash = dx_hack_hash_unsigned(name, len);
167 break;
168 case DX_HASH_LEGACY:
169 hash = dx_hack_hash_signed(name, len);
170 break;
171 case DX_HASH_HALF_MD4_UNSIGNED:
172 str2hashbuf = str2hashbuf_unsigned;
173 case DX_HASH_HALF_MD4:
174 p = name;
175 while (len > 0) {
176 (*str2hashbuf)(p, len, in, 8);
177 half_md4_transform(buf, in);
178 len -= 32;
179 p += 32;
180 }
181 minor_hash = buf[2];
182 hash = buf[1];
183 break;
184 case DX_HASH_TEA_UNSIGNED:
185 str2hashbuf = str2hashbuf_unsigned;
186 case DX_HASH_TEA:
187 p = name;
188 while (len > 0) {
189 (*str2hashbuf)(p, len, in, 4);
190 TEA_transform(buf, in);
191 len -= 16;
192 p += 16;
193 }
194 hash = buf[0];
195 minor_hash = buf[1];
196 break;
197 default:
198 hinfo->hash = 0;
199 return -1;
200 }
201 hash = hash & ~1;
202 if (hash == (EXT4_HTREE_EOF_32BIT << 1))
203 hash = (EXT4_HTREE_EOF_32BIT - 1) << 1;
204 hinfo->hash = hash;
205 hinfo->minor_hash = minor_hash;
206 return 0;
207}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/ext4/hash.c
4 *
5 * Copyright (C) 2002 by Theodore Ts'o
6 */
7
8#include <linux/fs.h>
9#include <linux/unicode.h>
10#include <linux/compiler.h>
11#include <linux/bitops.h>
12#include "ext4.h"
13
14#define DELTA 0x9E3779B9
15
16static void TEA_transform(__u32 buf[4], __u32 const in[])
17{
18 __u32 sum = 0;
19 __u32 b0 = buf[0], b1 = buf[1];
20 __u32 a = in[0], b = in[1], c = in[2], d = in[3];
21 int n = 16;
22
23 do {
24 sum += DELTA;
25 b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
26 b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
27 } while (--n);
28
29 buf[0] += b0;
30 buf[1] += b1;
31}
32
33/* F, G and H are basic MD4 functions: selection, majority, parity */
34#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
35#define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
36#define H(x, y, z) ((x) ^ (y) ^ (z))
37
38/*
39 * The generic round function. The application is so specific that
40 * we don't bother protecting all the arguments with parens, as is generally
41 * good macro practice, in favor of extra legibility.
42 * Rotation is separate from addition to prevent recomputation
43 */
44#define ROUND(f, a, b, c, d, x, s) \
45 (a += f(b, c, d) + x, a = rol32(a, s))
46#define K1 0
47#define K2 013240474631UL
48#define K3 015666365641UL
49
50/*
51 * Basic cut-down MD4 transform. Returns only 32 bits of result.
52 */
53static __u32 half_md4_transform(__u32 buf[4], __u32 const in[8])
54{
55 __u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
56
57 /* Round 1 */
58 ROUND(F, a, b, c, d, in[0] + K1, 3);
59 ROUND(F, d, a, b, c, in[1] + K1, 7);
60 ROUND(F, c, d, a, b, in[2] + K1, 11);
61 ROUND(F, b, c, d, a, in[3] + K1, 19);
62 ROUND(F, a, b, c, d, in[4] + K1, 3);
63 ROUND(F, d, a, b, c, in[5] + K1, 7);
64 ROUND(F, c, d, a, b, in[6] + K1, 11);
65 ROUND(F, b, c, d, a, in[7] + K1, 19);
66
67 /* Round 2 */
68 ROUND(G, a, b, c, d, in[1] + K2, 3);
69 ROUND(G, d, a, b, c, in[3] + K2, 5);
70 ROUND(G, c, d, a, b, in[5] + K2, 9);
71 ROUND(G, b, c, d, a, in[7] + K2, 13);
72 ROUND(G, a, b, c, d, in[0] + K2, 3);
73 ROUND(G, d, a, b, c, in[2] + K2, 5);
74 ROUND(G, c, d, a, b, in[4] + K2, 9);
75 ROUND(G, b, c, d, a, in[6] + K2, 13);
76
77 /* Round 3 */
78 ROUND(H, a, b, c, d, in[3] + K3, 3);
79 ROUND(H, d, a, b, c, in[7] + K3, 9);
80 ROUND(H, c, d, a, b, in[2] + K3, 11);
81 ROUND(H, b, c, d, a, in[6] + K3, 15);
82 ROUND(H, a, b, c, d, in[1] + K3, 3);
83 ROUND(H, d, a, b, c, in[5] + K3, 9);
84 ROUND(H, c, d, a, b, in[0] + K3, 11);
85 ROUND(H, b, c, d, a, in[4] + K3, 15);
86
87 buf[0] += a;
88 buf[1] += b;
89 buf[2] += c;
90 buf[3] += d;
91
92 return buf[1]; /* "most hashed" word */
93}
94#undef ROUND
95#undef K1
96#undef K2
97#undef K3
98#undef F
99#undef G
100#undef H
101
102/* The old legacy hash */
103static __u32 dx_hack_hash_unsigned(const char *name, int len)
104{
105 __u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
106 const unsigned char *ucp = (const unsigned char *) name;
107
108 while (len--) {
109 hash = hash1 + (hash0 ^ (((int) *ucp++) * 7152373));
110
111 if (hash & 0x80000000)
112 hash -= 0x7fffffff;
113 hash1 = hash0;
114 hash0 = hash;
115 }
116 return hash0 << 1;
117}
118
119static __u32 dx_hack_hash_signed(const char *name, int len)
120{
121 __u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
122 const signed char *scp = (const signed char *) name;
123
124 while (len--) {
125 hash = hash1 + (hash0 ^ (((int) *scp++) * 7152373));
126
127 if (hash & 0x80000000)
128 hash -= 0x7fffffff;
129 hash1 = hash0;
130 hash0 = hash;
131 }
132 return hash0 << 1;
133}
134
135static void str2hashbuf_signed(const char *msg, int len, __u32 *buf, int num)
136{
137 __u32 pad, val;
138 int i;
139 const signed char *scp = (const signed char *) msg;
140
141 pad = (__u32)len | ((__u32)len << 8);
142 pad |= pad << 16;
143
144 val = pad;
145 if (len > num*4)
146 len = num * 4;
147 for (i = 0; i < len; i++) {
148 val = ((int) scp[i]) + (val << 8);
149 if ((i % 4) == 3) {
150 *buf++ = val;
151 val = pad;
152 num--;
153 }
154 }
155 if (--num >= 0)
156 *buf++ = val;
157 while (--num >= 0)
158 *buf++ = pad;
159}
160
161static void str2hashbuf_unsigned(const char *msg, int len, __u32 *buf, int num)
162{
163 __u32 pad, val;
164 int i;
165 const unsigned char *ucp = (const unsigned char *) msg;
166
167 pad = (__u32)len | ((__u32)len << 8);
168 pad |= pad << 16;
169
170 val = pad;
171 if (len > num*4)
172 len = num * 4;
173 for (i = 0; i < len; i++) {
174 val = ((int) ucp[i]) + (val << 8);
175 if ((i % 4) == 3) {
176 *buf++ = val;
177 val = pad;
178 num--;
179 }
180 }
181 if (--num >= 0)
182 *buf++ = val;
183 while (--num >= 0)
184 *buf++ = pad;
185}
186
187/*
188 * Returns the hash of a filename. If len is 0 and name is NULL, then
189 * this function can be used to test whether or not a hash version is
190 * supported.
191 *
192 * The seed is an 4 longword (32 bits) "secret" which can be used to
193 * uniquify a hash. If the seed is all zero's, then some default seed
194 * may be used.
195 *
196 * A particular hash version specifies whether or not the seed is
197 * represented, and whether or not the returned hash is 32 bits or 64
198 * bits. 32 bit hashes will return 0 for the minor hash.
199 */
200static int __ext4fs_dirhash(const char *name, int len,
201 struct dx_hash_info *hinfo)
202{
203 __u32 hash;
204 __u32 minor_hash = 0;
205 const char *p;
206 int i;
207 __u32 in[8], buf[4];
208 void (*str2hashbuf)(const char *, int, __u32 *, int) =
209 str2hashbuf_signed;
210
211 /* Initialize the default seed for the hash checksum functions */
212 buf[0] = 0x67452301;
213 buf[1] = 0xefcdab89;
214 buf[2] = 0x98badcfe;
215 buf[3] = 0x10325476;
216
217 /* Check to see if the seed is all zero's */
218 if (hinfo->seed) {
219 for (i = 0; i < 4; i++) {
220 if (hinfo->seed[i]) {
221 memcpy(buf, hinfo->seed, sizeof(buf));
222 break;
223 }
224 }
225 }
226
227 switch (hinfo->hash_version) {
228 case DX_HASH_LEGACY_UNSIGNED:
229 hash = dx_hack_hash_unsigned(name, len);
230 break;
231 case DX_HASH_LEGACY:
232 hash = dx_hack_hash_signed(name, len);
233 break;
234 case DX_HASH_HALF_MD4_UNSIGNED:
235 str2hashbuf = str2hashbuf_unsigned;
236 /* fall through */
237 case DX_HASH_HALF_MD4:
238 p = name;
239 while (len > 0) {
240 (*str2hashbuf)(p, len, in, 8);
241 half_md4_transform(buf, in);
242 len -= 32;
243 p += 32;
244 }
245 minor_hash = buf[2];
246 hash = buf[1];
247 break;
248 case DX_HASH_TEA_UNSIGNED:
249 str2hashbuf = str2hashbuf_unsigned;
250 /* fall through */
251 case DX_HASH_TEA:
252 p = name;
253 while (len > 0) {
254 (*str2hashbuf)(p, len, in, 4);
255 TEA_transform(buf, in);
256 len -= 16;
257 p += 16;
258 }
259 hash = buf[0];
260 minor_hash = buf[1];
261 break;
262 default:
263 hinfo->hash = 0;
264 return -1;
265 }
266 hash = hash & ~1;
267 if (hash == (EXT4_HTREE_EOF_32BIT << 1))
268 hash = (EXT4_HTREE_EOF_32BIT - 1) << 1;
269 hinfo->hash = hash;
270 hinfo->minor_hash = minor_hash;
271 return 0;
272}
273
274int ext4fs_dirhash(const struct inode *dir, const char *name, int len,
275 struct dx_hash_info *hinfo)
276{
277#ifdef CONFIG_UNICODE
278 const struct unicode_map *um = EXT4_SB(dir->i_sb)->s_encoding;
279 int r, dlen;
280 unsigned char *buff;
281 struct qstr qstr = {.name = name, .len = len };
282
283 if (len && IS_CASEFOLDED(dir) && um) {
284 buff = kzalloc(sizeof(char) * PATH_MAX, GFP_KERNEL);
285 if (!buff)
286 return -ENOMEM;
287
288 dlen = utf8_casefold(um, &qstr, buff, PATH_MAX);
289 if (dlen < 0) {
290 kfree(buff);
291 goto opaque_seq;
292 }
293
294 r = __ext4fs_dirhash(buff, dlen, hinfo);
295
296 kfree(buff);
297 return r;
298 }
299opaque_seq:
300#endif
301 return __ext4fs_dirhash(name, len, hinfo);
302}