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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 struct inode *dir, 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 fallthrough;
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 fallthrough;
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 case DX_HASH_SIPHASH:
263 {
264 struct qstr qname = QSTR_INIT(name, len);
265 __u64 combined_hash;
266
267 if (fscrypt_has_encryption_key(dir)) {
268 combined_hash = fscrypt_fname_siphash(dir, &qname);
269 } else {
270 ext4_warning_inode(dir, "Siphash requires key");
271 return -1;
272 }
273
274 hash = (__u32)(combined_hash >> 32);
275 minor_hash = (__u32)combined_hash;
276 break;
277 }
278 default:
279 hinfo->hash = 0;
280 return -1;
281 }
282 hash = hash & ~1;
283 if (hash == (EXT4_HTREE_EOF_32BIT << 1))
284 hash = (EXT4_HTREE_EOF_32BIT - 1) << 1;
285 hinfo->hash = hash;
286 hinfo->minor_hash = minor_hash;
287 return 0;
288}
289
290int ext4fs_dirhash(const struct inode *dir, const char *name, int len,
291 struct dx_hash_info *hinfo)
292{
293#if IS_ENABLED(CONFIG_UNICODE)
294 const struct unicode_map *um = dir->i_sb->s_encoding;
295 int r, dlen;
296 unsigned char *buff;
297 struct qstr qstr = {.name = name, .len = len };
298
299 if (len && IS_CASEFOLDED(dir) && um &&
300 (!IS_ENCRYPTED(dir) || fscrypt_has_encryption_key(dir))) {
301 buff = kzalloc(sizeof(char) * PATH_MAX, GFP_KERNEL);
302 if (!buff)
303 return -ENOMEM;
304
305 dlen = utf8_casefold(um, &qstr, buff, PATH_MAX);
306 if (dlen < 0) {
307 kfree(buff);
308 goto opaque_seq;
309 }
310
311 r = __ext4fs_dirhash(dir, buff, dlen, hinfo);
312
313 kfree(buff);
314 return r;
315 }
316opaque_seq:
317#endif
318 return __ext4fs_dirhash(dir, name, len, hinfo);
319}
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/jbd2.h>
14#include <linux/cryptohash.h>
15#include "ext4.h"
16
17#define DELTA 0x9E3779B9
18
19static void TEA_transform(__u32 buf[4], __u32 const in[])
20{
21 __u32 sum = 0;
22 __u32 b0 = buf[0], b1 = buf[1];
23 __u32 a = in[0], b = in[1], c = in[2], d = in[3];
24 int n = 16;
25
26 do {
27 sum += DELTA;
28 b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
29 b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
30 } while (--n);
31
32 buf[0] += b0;
33 buf[1] += b1;
34}
35
36
37/* The old legacy hash */
38static __u32 dx_hack_hash_unsigned(const char *name, int len)
39{
40 __u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
41 const unsigned char *ucp = (const unsigned char *) name;
42
43 while (len--) {
44 hash = hash1 + (hash0 ^ (((int) *ucp++) * 7152373));
45
46 if (hash & 0x80000000)
47 hash -= 0x7fffffff;
48 hash1 = hash0;
49 hash0 = hash;
50 }
51 return hash0 << 1;
52}
53
54static __u32 dx_hack_hash_signed(const char *name, int len)
55{
56 __u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
57 const signed char *scp = (const signed char *) name;
58
59 while (len--) {
60 hash = hash1 + (hash0 ^ (((int) *scp++) * 7152373));
61
62 if (hash & 0x80000000)
63 hash -= 0x7fffffff;
64 hash1 = hash0;
65 hash0 = hash;
66 }
67 return hash0 << 1;
68}
69
70static void str2hashbuf_signed(const char *msg, int len, __u32 *buf, int num)
71{
72 __u32 pad, val;
73 int i;
74 const signed char *scp = (const signed char *) msg;
75
76 pad = (__u32)len | ((__u32)len << 8);
77 pad |= pad << 16;
78
79 val = pad;
80 if (len > num*4)
81 len = num * 4;
82 for (i = 0; i < len; i++) {
83 if ((i % 4) == 0)
84 val = pad;
85 val = ((int) scp[i]) + (val << 8);
86 if ((i % 4) == 3) {
87 *buf++ = val;
88 val = pad;
89 num--;
90 }
91 }
92 if (--num >= 0)
93 *buf++ = val;
94 while (--num >= 0)
95 *buf++ = pad;
96}
97
98static void str2hashbuf_unsigned(const char *msg, int len, __u32 *buf, int num)
99{
100 __u32 pad, val;
101 int i;
102 const unsigned char *ucp = (const unsigned char *) msg;
103
104 pad = (__u32)len | ((__u32)len << 8);
105 pad |= pad << 16;
106
107 val = pad;
108 if (len > num*4)
109 len = num * 4;
110 for (i = 0; i < len; i++) {
111 if ((i % 4) == 0)
112 val = pad;
113 val = ((int) ucp[i]) + (val << 8);
114 if ((i % 4) == 3) {
115 *buf++ = val;
116 val = pad;
117 num--;
118 }
119 }
120 if (--num >= 0)
121 *buf++ = val;
122 while (--num >= 0)
123 *buf++ = pad;
124}
125
126/*
127 * Returns the hash of a filename. If len is 0 and name is NULL, then
128 * this function can be used to test whether or not a hash version is
129 * supported.
130 *
131 * The seed is an 4 longword (32 bits) "secret" which can be used to
132 * uniquify a hash. If the seed is all zero's, then some default seed
133 * may be used.
134 *
135 * A particular hash version specifies whether or not the seed is
136 * represented, and whether or not the returned hash is 32 bits or 64
137 * bits. 32 bit hashes will return 0 for the minor hash.
138 */
139int ext4fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo)
140{
141 __u32 hash;
142 __u32 minor_hash = 0;
143 const char *p;
144 int i;
145 __u32 in[8], buf[4];
146 void (*str2hashbuf)(const char *, int, __u32 *, int) =
147 str2hashbuf_signed;
148
149 /* Initialize the default seed for the hash checksum functions */
150 buf[0] = 0x67452301;
151 buf[1] = 0xefcdab89;
152 buf[2] = 0x98badcfe;
153 buf[3] = 0x10325476;
154
155 /* Check to see if the seed is all zero's */
156 if (hinfo->seed) {
157 for (i = 0; i < 4; i++) {
158 if (hinfo->seed[i]) {
159 memcpy(buf, hinfo->seed, sizeof(buf));
160 break;
161 }
162 }
163 }
164
165 switch (hinfo->hash_version) {
166 case DX_HASH_LEGACY_UNSIGNED:
167 hash = dx_hack_hash_unsigned(name, len);
168 break;
169 case DX_HASH_LEGACY:
170 hash = dx_hack_hash_signed(name, len);
171 break;
172 case DX_HASH_HALF_MD4_UNSIGNED:
173 str2hashbuf = str2hashbuf_unsigned;
174 case DX_HASH_HALF_MD4:
175 p = name;
176 while (len > 0) {
177 (*str2hashbuf)(p, len, in, 8);
178 half_md4_transform(buf, in);
179 len -= 32;
180 p += 32;
181 }
182 minor_hash = buf[2];
183 hash = buf[1];
184 break;
185 case DX_HASH_TEA_UNSIGNED:
186 str2hashbuf = str2hashbuf_unsigned;
187 case DX_HASH_TEA:
188 p = name;
189 while (len > 0) {
190 (*str2hashbuf)(p, len, in, 4);
191 TEA_transform(buf, in);
192 len -= 16;
193 p += 16;
194 }
195 hash = buf[0];
196 minor_hash = buf[1];
197 break;
198 default:
199 hinfo->hash = 0;
200 return -1;
201 }
202 hash = hash & ~1;
203 if (hash == (EXT4_HTREE_EOF_32BIT << 1))
204 hash = (EXT4_HTREE_EOF_32BIT - 1) << 1;
205 hinfo->hash = hash;
206 hinfo->minor_hash = minor_hash;
207 return 0;
208}