xref: /freebsd/sys/fs/ext2fs/ext2_hash.c (revision 7447ca0eb235974642312b9555caec00b57d8fc1)
1 /*-
2  * Copyright (c) 2010, 2013 Zheng Liu <lz@freebsd.org>
3  * Copyright (c) 2012, Vyacheslav Matyushin
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  * $FreeBSD$
28  */
29 
30 /*
31  * The following notice applies to the code in ext2_half_md4():
32  *
33  * Copyright (C) 1990-2, RSA Data Security, Inc. All rights reserved.
34  *
35  * License to copy and use this software is granted provided that it
36  * is identified as the "RSA Data Security, Inc. MD4 Message-Digest
37  * Algorithm" in all material mentioning or referencing this software
38  * or this function.
39  *
40  * License is also granted to make and use derivative works provided
41  * that such works are identified as "derived from the RSA Data
42  * Security, Inc. MD4 Message-Digest Algorithm" in all material
43  * mentioning or referencing the derived work.
44  *
45  * RSA Data Security, Inc. makes no representations concerning either
46  * the merchantability of this software or the suitability of this
47  * software for any particular purpose. It is provided "as is"
48  * without express or implied warranty of any kind.
49  *
50  * These notices must be retained in any copies of any part of this
51  * documentation and/or software.
52  */
53 
54 #include <sys/param.h>
55 #include <sys/systm.h>
56 #include <sys/conf.h>
57 #include <sys/vnode.h>
58 #include <sys/stat.h>
59 #include <sys/mount.h>
60 
61 #include <fs/ext2fs/htree.h>
62 #include <fs/ext2fs/inode.h>
63 #include <fs/ext2fs/ext2_mount.h>
64 #include <fs/ext2fs/ext2_extern.h>
65 
66 /* F, G, and H are MD4 functions */
67 #define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
68 #define G(x, y, z) (((x) & (y)) | ((x) & (z)) | ((y) & (z)))
69 #define H(x, y, z) ((x) ^ (y) ^ (z))
70 
71 /* ROTATE_LEFT rotates x left n bits */
72 #define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))
73 
74 /*
75  * FF, GG, and HH are transformations for rounds 1, 2, and 3.
76  * Rotation is separated from addition to prevent recomputation.
77  */
78 #define FF(a, b, c, d, x, s) { \
79 	(a) += F ((b), (c), (d)) + (x); \
80 	(a) = ROTATE_LEFT ((a), (s)); \
81 }
82 
83 #define GG(a, b, c, d, x, s) { \
84 	(a) += G ((b), (c), (d)) + (x) + (uint32_t)0x5A827999; \
85 	(a) = ROTATE_LEFT ((a), (s)); \
86 }
87 
88 #define HH(a, b, c, d, x, s) { \
89 	(a) += H ((b), (c), (d)) + (x) + (uint32_t)0x6ED9EBA1; \
90 	(a) = ROTATE_LEFT ((a), (s)); \
91 }
92 
93 /*
94  * MD4 basic transformation.  It transforms state based on block.
95  *
96  * This is a half md4 algorithm since Linux uses this algorithm for dir
97  * index.  This function is derived from the RSA Data Security, Inc. MD4
98  * Message-Digest Algorithm and was modified as necessary.
99  *
100  * The return value of this function is uint32_t in Linux, but actually we don't
101  * need to check this value, so in our version this function doesn't return any
102  * value.
103  */
104 static void
105 ext2_half_md4(uint32_t hash[4], uint32_t data[8])
106 {
107 	uint32_t a = hash[0], b = hash[1], c = hash[2], d = hash[3];
108 
109 	/* Round 1 */
110 	FF(a, b, c, d, data[0],  3);
111 	FF(d, a, b, c, data[1],  7);
112 	FF(c, d, a, b, data[2], 11);
113 	FF(b, c, d, a, data[3], 19);
114 	FF(a, b, c, d, data[4],  3);
115 	FF(d, a, b, c, data[5],  7);
116 	FF(c, d, a, b, data[6], 11);
117 	FF(b, c, d, a, data[7], 19);
118 
119 	/* Round 2 */
120 	GG(a, b, c, d, data[1],  3);
121 	GG(d, a, b, c, data[3],  5);
122 	GG(c, d, a, b, data[5],  9);
123 	GG(b, c, d, a, data[7], 13);
124 	GG(a, b, c, d, data[0],  3);
125 	GG(d, a, b, c, data[2],  5);
126 	GG(c, d, a, b, data[4],  9);
127 	GG(b, c, d, a, data[6], 13);
128 
129 	/* Round 3 */
130 	HH(a, b, c, d, data[3],  3);
131 	HH(d, a, b, c, data[7],  9);
132 	HH(c, d, a, b, data[2], 11);
133 	HH(b, c, d, a, data[6], 15);
134 	HH(a, b, c, d, data[1],  3);
135 	HH(d, a, b, c, data[5],  9);
136 	HH(c, d, a, b, data[0], 11);
137 	HH(b, c, d, a, data[4], 15);
138 
139 	hash[0] += a;
140 	hash[1] += b;
141 	hash[2] += c;
142 	hash[3] += d;
143 }
144 
145 /*
146  * Tiny Encryption Algorithm.
147  */
148 static void
149 ext2_tea(uint32_t hash[4], uint32_t data[8])
150 {
151 	uint32_t tea_delta = 0x9E3779B9;
152 	uint32_t sum;
153 	uint32_t x = hash[0], y = hash[1];
154 	int n = 16;
155 	int i = 1;
156 
157 	while (n-- > 0) {
158 		sum = i * tea_delta;
159 		x += ((y << 4) + data[0]) ^ (y + sum) ^ ((y >> 5) + data[1]);
160 		y += ((x << 4) + data[2]) ^ (x + sum) ^ ((x >> 5) + data[3]);
161 		i++;
162 	}
163 
164 	hash[0] += x;
165 	hash[1] += y;
166 }
167 
168 static uint32_t
169 ext2_legacy_hash(const char *name, int len, int unsigned_char)
170 {
171 	uint32_t h0, h1 = 0x12A3FE2D, h2 = 0x37ABE8F9;
172 	uint32_t multi = 0x6D22F5;
173 	const unsigned char *uname = (const unsigned char *)name;
174 	const signed char *sname = (const signed char *)name;
175 	int val, i;
176 
177 	for (i = 0; i < len; i++) {
178 		if (unsigned_char)
179 			val = (u_int)*uname++;
180 		else
181 			val = (int)*sname++;
182 
183 		h0 = h2 + (h1 ^ (val * multi));
184 		if (h0 & 0x80000000)
185 			h0 -= 0x7FFFFFFF;
186 		h2 = h1;
187 		h1 = h0;
188 	}
189 
190 	return (h1 << 1);
191 }
192 
193 static void
194 ext2_prep_hashbuf(const char *src, int slen, uint32_t *dst, int dlen,
195 	     int unsigned_char)
196 {
197 	uint32_t padding = slen | (slen << 8) | (slen << 16) | (slen << 24);
198 	uint32_t buf_val;
199 	const unsigned char *ubuf = (const unsigned char *)src;
200 	const signed char *sbuf = (const signed char *)src;
201 	int len, i;
202 	int buf_byte;
203 
204 	if (slen > dlen)
205 		len = dlen;
206 	else
207 		len = slen;
208 
209 	buf_val = padding;
210 
211 	for (i = 0; i < len; i++) {
212 		if (unsigned_char)
213 			buf_byte = (u_int)ubuf[i];
214 		else
215 			buf_byte = (int)sbuf[i];
216 
217 		if ((i % 4) == 0)
218 			buf_val = padding;
219 
220 		buf_val <<= 8;
221 		buf_val += buf_byte;
222 
223 		if ((i % 4) == 3) {
224 			*dst++ = buf_val;
225 			dlen -= sizeof(uint32_t);
226 			buf_val = padding;
227 		}
228 	}
229 
230 	dlen -= sizeof(uint32_t);
231 	if (dlen >= 0)
232 		*dst++ = buf_val;
233 
234 	dlen -= sizeof(uint32_t);
235 	while (dlen >= 0) {
236 		*dst++ = padding;
237 		dlen -= sizeof(uint32_t);
238 	}
239 }
240 
241 int
242 ext2_htree_hash(const char *name, int len,
243 		uint32_t *hash_seed, int hash_version,
244 		uint32_t *hash_major, uint32_t *hash_minor)
245 {
246 	uint32_t hash[4];
247 	uint32_t data[8];
248 	uint32_t major = 0, minor = 0;
249 	int unsigned_char = 0;
250 
251 	if (!name || !hash_major)
252 		return (-1);
253 
254 	if (len < 1 || len > 255)
255 		goto error;
256 
257 	hash[0] = 0x67452301;
258 	hash[1] = 0xEFCDAB89;
259 	hash[2] = 0x98BADCFE;
260 	hash[3] = 0x10325476;
261 
262 	if (hash_seed)
263 		memcpy(hash, hash_seed, sizeof(hash));
264 
265 	switch (hash_version) {
266 	case EXT2_HTREE_TEA_UNSIGNED:
267 		unsigned_char = 1;
268 		/* FALLTHROUGH */
269 	case EXT2_HTREE_TEA:
270 		while (len > 0) {
271 			ext2_prep_hashbuf(name, len, data, 16, unsigned_char);
272 			ext2_tea(hash, data);
273 			len -= 16;
274 			name += 16;
275 		}
276 		major = hash[0];
277 		minor = hash[1];
278 		break;
279 	case EXT2_HTREE_LEGACY_UNSIGNED:
280 		unsigned_char = 1;
281 		/* FALLTHROUGH */
282 	case EXT2_HTREE_LEGACY:
283 		major = ext2_legacy_hash(name, len, unsigned_char);
284 		break;
285 	case EXT2_HTREE_HALF_MD4_UNSIGNED:
286 		unsigned_char = 1;
287 		/* FALLTHROUGH */
288 	case EXT2_HTREE_HALF_MD4:
289 		while (len > 0) {
290 			ext2_prep_hashbuf(name, len, data, 32, unsigned_char);
291 			ext2_half_md4(hash, data);
292 			len -= 32;
293 			name += 32;
294 		}
295 		major = hash[1];
296 		minor = hash[2];
297 		break;
298 	default:
299 		goto error;
300 	}
301 
302 	major &= ~1;
303 	if (major == (EXT2_HTREE_EOF << 1))
304 		major = (EXT2_HTREE_EOF - 1) << 1;
305 	*hash_major = major;
306 	if (hash_minor)
307 		*hash_minor = minor;
308 
309 	return (0);
310 
311 error:
312 	*hash_major = 0;
313 	if (hash_minor)
314 		*hash_minor = 0;
315 	return (-1);
316 }
317