xref: /freebsd/sys/fs/ext2fs/ext2_hash.c (revision 3c5ba95ad12285ad37c182a4bfc1b240ec6d18a7)
1 /*-
2  * SPDX-License-Identifier: (BSD-2-Clause-FreeBSD AND RSA-MD)
3  *
4  * Copyright (c) 2010, 2013 Zheng Liu <lz@freebsd.org>
5  * Copyright (c) 2012, Vyacheslav Matyushin
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * $FreeBSD$
30  */
31 
32 /*
33  * The following notice applies to the code in ext2_half_md4():
34  *
35  * Copyright (C) 1990-2, RSA Data Security, Inc. All rights reserved.
36  *
37  * License to copy and use this software is granted provided that it
38  * is identified as the "RSA Data Security, Inc. MD4 Message-Digest
39  * Algorithm" in all material mentioning or referencing this software
40  * or this function.
41  *
42  * License is also granted to make and use derivative works provided
43  * that such works are identified as "derived from the RSA Data
44  * Security, Inc. MD4 Message-Digest Algorithm" in all material
45  * mentioning or referencing the derived work.
46  *
47  * RSA Data Security, Inc. makes no representations concerning either
48  * the merchantability of this software or the suitability of this
49  * software for any particular purpose. It is provided "as is"
50  * without express or implied warranty of any kind.
51  *
52  * These notices must be retained in any copies of any part of this
53  * documentation and/or software.
54  */
55 
56 #include <sys/param.h>
57 #include <sys/systm.h>
58 #include <sys/conf.h>
59 #include <sys/vnode.h>
60 #include <sys/stat.h>
61 #include <sys/mount.h>
62 
63 #include <fs/ext2fs/ext2fs.h>
64 #include <fs/ext2fs/fs.h>
65 #include <fs/ext2fs/htree.h>
66 #include <fs/ext2fs/inode.h>
67 #include <fs/ext2fs/ext2_mount.h>
68 #include <fs/ext2fs/ext2_extern.h>
69 
70 /* F, G, and H are MD4 functions */
71 #define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
72 #define G(x, y, z) (((x) & (y)) | ((x) & (z)) | ((y) & (z)))
73 #define H(x, y, z) ((x) ^ (y) ^ (z))
74 
75 /* ROTATE_LEFT rotates x left n bits */
76 #define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))
77 
78 /*
79  * FF, GG, and HH are transformations for rounds 1, 2, and 3.
80  * Rotation is separated from addition to prevent recomputation.
81  */
82 #define FF(a, b, c, d, x, s) { \
83 	(a) += F ((b), (c), (d)) + (x); \
84 	(a) = ROTATE_LEFT ((a), (s)); \
85 }
86 
87 #define GG(a, b, c, d, x, s) { \
88 	(a) += G ((b), (c), (d)) + (x) + (uint32_t)0x5A827999; \
89 	(a) = ROTATE_LEFT ((a), (s)); \
90 }
91 
92 #define HH(a, b, c, d, x, s) { \
93 	(a) += H ((b), (c), (d)) + (x) + (uint32_t)0x6ED9EBA1; \
94 	(a) = ROTATE_LEFT ((a), (s)); \
95 }
96 
97 /*
98  * MD4 basic transformation.  It transforms state based on block.
99  *
100  * This is a half md4 algorithm since Linux uses this algorithm for dir
101  * index.  This function is derived from the RSA Data Security, Inc. MD4
102  * Message-Digest Algorithm and was modified as necessary.
103  *
104  * The return value of this function is uint32_t in Linux, but actually we don't
105  * need to check this value, so in our version this function doesn't return any
106  * value.
107  */
108 static void
109 ext2_half_md4(uint32_t hash[4], uint32_t data[8])
110 {
111 	uint32_t a = hash[0], b = hash[1], c = hash[2], d = hash[3];
112 
113 	/* Round 1 */
114 	FF(a, b, c, d, data[0],  3);
115 	FF(d, a, b, c, data[1],  7);
116 	FF(c, d, a, b, data[2], 11);
117 	FF(b, c, d, a, data[3], 19);
118 	FF(a, b, c, d, data[4],  3);
119 	FF(d, a, b, c, data[5],  7);
120 	FF(c, d, a, b, data[6], 11);
121 	FF(b, c, d, a, data[7], 19);
122 
123 	/* Round 2 */
124 	GG(a, b, c, d, data[1],  3);
125 	GG(d, a, b, c, data[3],  5);
126 	GG(c, d, a, b, data[5],  9);
127 	GG(b, c, d, a, data[7], 13);
128 	GG(a, b, c, d, data[0],  3);
129 	GG(d, a, b, c, data[2],  5);
130 	GG(c, d, a, b, data[4],  9);
131 	GG(b, c, d, a, data[6], 13);
132 
133 	/* Round 3 */
134 	HH(a, b, c, d, data[3],  3);
135 	HH(d, a, b, c, data[7],  9);
136 	HH(c, d, a, b, data[2], 11);
137 	HH(b, c, d, a, data[6], 15);
138 	HH(a, b, c, d, data[1],  3);
139 	HH(d, a, b, c, data[5],  9);
140 	HH(c, d, a, b, data[0], 11);
141 	HH(b, c, d, a, data[4], 15);
142 
143 	hash[0] += a;
144 	hash[1] += b;
145 	hash[2] += c;
146 	hash[3] += d;
147 }
148 
149 /*
150  * Tiny Encryption Algorithm.
151  */
152 static void
153 ext2_tea(uint32_t hash[4], uint32_t data[8])
154 {
155 	uint32_t tea_delta = 0x9E3779B9;
156 	uint32_t sum;
157 	uint32_t x = hash[0], y = hash[1];
158 	int n = 16;
159 	int i = 1;
160 
161 	while (n-- > 0) {
162 		sum = i * tea_delta;
163 		x += ((y << 4) + data[0]) ^ (y + sum) ^ ((y >> 5) + data[1]);
164 		y += ((x << 4) + data[2]) ^ (x + sum) ^ ((x >> 5) + data[3]);
165 		i++;
166 	}
167 
168 	hash[0] += x;
169 	hash[1] += y;
170 }
171 
172 static uint32_t
173 ext2_legacy_hash(const char *name, int len, int unsigned_char)
174 {
175 	uint32_t h0, h1 = 0x12A3FE2D, h2 = 0x37ABE8F9;
176 	uint32_t multi = 0x6D22F5;
177 	const unsigned char *uname = (const unsigned char *)name;
178 	const signed char *sname = (const signed char *)name;
179 	int val, i;
180 
181 	for (i = 0; i < len; i++) {
182 		if (unsigned_char)
183 			val = (u_int)*uname++;
184 		else
185 			val = (int)*sname++;
186 
187 		h0 = h2 + (h1 ^ (val * multi));
188 		if (h0 & 0x80000000)
189 			h0 -= 0x7FFFFFFF;
190 		h2 = h1;
191 		h1 = h0;
192 	}
193 
194 	return (h1 << 1);
195 }
196 
197 static void
198 ext2_prep_hashbuf(const char *src, int slen, uint32_t *dst, int dlen,
199     int unsigned_char)
200 {
201 	uint32_t padding = slen | (slen << 8) | (slen << 16) | (slen << 24);
202 	uint32_t buf_val;
203 	const unsigned char *ubuf = (const unsigned char *)src;
204 	const signed char *sbuf = (const signed char *)src;
205 	int len, i;
206 	int buf_byte;
207 
208 	if (slen > dlen)
209 		len = dlen;
210 	else
211 		len = slen;
212 
213 	buf_val = padding;
214 
215 	for (i = 0; i < len; i++) {
216 		if (unsigned_char)
217 			buf_byte = (u_int)ubuf[i];
218 		else
219 			buf_byte = (int)sbuf[i];
220 
221 		if ((i % 4) == 0)
222 			buf_val = padding;
223 
224 		buf_val <<= 8;
225 		buf_val += buf_byte;
226 
227 		if ((i % 4) == 3) {
228 			*dst++ = buf_val;
229 			dlen -= sizeof(uint32_t);
230 			buf_val = padding;
231 		}
232 	}
233 
234 	dlen -= sizeof(uint32_t);
235 	if (dlen >= 0)
236 		*dst++ = buf_val;
237 
238 	dlen -= sizeof(uint32_t);
239 	while (dlen >= 0) {
240 		*dst++ = padding;
241 		dlen -= sizeof(uint32_t);
242 	}
243 }
244 
245 int
246 ext2_htree_hash(const char *name, int len,
247     uint32_t *hash_seed, int hash_version,
248     uint32_t *hash_major, uint32_t *hash_minor)
249 {
250 	uint32_t hash[4];
251 	uint32_t data[8];
252 	uint32_t major = 0, minor = 0;
253 	int unsigned_char = 0;
254 
255 	if (!name || !hash_major)
256 		return (-1);
257 
258 	if (len < 1 || len > 255)
259 		goto error;
260 
261 	hash[0] = 0x67452301;
262 	hash[1] = 0xEFCDAB89;
263 	hash[2] = 0x98BADCFE;
264 	hash[3] = 0x10325476;
265 
266 	if (hash_seed)
267 		memcpy(hash, hash_seed, sizeof(hash));
268 
269 	switch (hash_version) {
270 	case EXT2_HTREE_TEA_UNSIGNED:
271 		unsigned_char = 1;
272 		/* FALLTHROUGH */
273 	case EXT2_HTREE_TEA:
274 		while (len > 0) {
275 			ext2_prep_hashbuf(name, len, data, 16, unsigned_char);
276 			ext2_tea(hash, data);
277 			len -= 16;
278 			name += 16;
279 		}
280 		major = hash[0];
281 		minor = hash[1];
282 		break;
283 	case EXT2_HTREE_LEGACY_UNSIGNED:
284 		unsigned_char = 1;
285 		/* FALLTHROUGH */
286 	case EXT2_HTREE_LEGACY:
287 		major = ext2_legacy_hash(name, len, unsigned_char);
288 		break;
289 	case EXT2_HTREE_HALF_MD4_UNSIGNED:
290 		unsigned_char = 1;
291 		/* FALLTHROUGH */
292 	case EXT2_HTREE_HALF_MD4:
293 		while (len > 0) {
294 			ext2_prep_hashbuf(name, len, data, 32, unsigned_char);
295 			ext2_half_md4(hash, data);
296 			len -= 32;
297 			name += 32;
298 		}
299 		major = hash[1];
300 		minor = hash[2];
301 		break;
302 	default:
303 		goto error;
304 	}
305 
306 	major &= ~1;
307 	if (major == (EXT2_HTREE_EOF << 1))
308 		major = (EXT2_HTREE_EOF - 1) << 1;
309 	*hash_major = major;
310 	if (hash_minor)
311 		*hash_minor = minor;
312 
313 	return (0);
314 
315 error:
316 	*hash_major = 0;
317 	if (hash_minor)
318 		*hash_minor = 0;
319 	return (-1);
320 }
321