crypt_md5.c raw
1 /*
2 * md5 crypt implementation
3 *
4 * original md5 crypt design is from Poul-Henning Kamp
5 * this implementation was created based on the code in freebsd
6 * at least 32bit int is assumed, key is limited and $1$ prefix is mandatory,
7 * on error "*" is returned
8 */
9 #include <string.h>
10 #include <stdint.h>
11
12 /* public domain md5 implementation based on rfc1321 and libtomcrypt */
13
14 struct md5 {
15 uint64_t len; /* processed message length */
16 uint32_t h[4]; /* hash state */
17 uint8_t buf[64]; /* message block buffer */
18 };
19
20 static uint32_t rol(uint32_t n, int k) { return (n << k) | (n >> (32-k)); }
21 #define F(x,y,z) (z ^ (x & (y ^ z)))
22 #define G(x,y,z) (y ^ (z & (y ^ x)))
23 #define H(x,y,z) (x ^ y ^ z)
24 #define I(x,y,z) (y ^ (x | ~z))
25 #define FF(a,b,c,d,w,s,t) a += F(b,c,d) + w + t; a = rol(a,s) + b
26 #define GG(a,b,c,d,w,s,t) a += G(b,c,d) + w + t; a = rol(a,s) + b
27 #define HH(a,b,c,d,w,s,t) a += H(b,c,d) + w + t; a = rol(a,s) + b
28 #define II(a,b,c,d,w,s,t) a += I(b,c,d) + w + t; a = rol(a,s) + b
29
30 static const uint32_t tab[64] = {
31 0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
32 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
33 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, 0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
34 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
35 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
36 0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
37 0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
38 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1, 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391
39 };
40
41 static void processblock(struct md5 *s, const uint8_t *buf)
42 {
43 uint32_t i, W[16], a, b, c, d;
44
45 for (i = 0; i < 16; i++) {
46 W[i] = buf[4*i];
47 W[i] |= (uint32_t)buf[4*i+1]<<8;
48 W[i] |= (uint32_t)buf[4*i+2]<<16;
49 W[i] |= (uint32_t)buf[4*i+3]<<24;
50 }
51
52 a = s->h[0];
53 b = s->h[1];
54 c = s->h[2];
55 d = s->h[3];
56
57 i = 0;
58 while (i < 16) {
59 FF(a,b,c,d, W[i], 7, tab[i]); i++;
60 FF(d,a,b,c, W[i], 12, tab[i]); i++;
61 FF(c,d,a,b, W[i], 17, tab[i]); i++;
62 FF(b,c,d,a, W[i], 22, tab[i]); i++;
63 }
64 while (i < 32) {
65 GG(a,b,c,d, W[(5*i+1)%16], 5, tab[i]); i++;
66 GG(d,a,b,c, W[(5*i+1)%16], 9, tab[i]); i++;
67 GG(c,d,a,b, W[(5*i+1)%16], 14, tab[i]); i++;
68 GG(b,c,d,a, W[(5*i+1)%16], 20, tab[i]); i++;
69 }
70 while (i < 48) {
71 HH(a,b,c,d, W[(3*i+5)%16], 4, tab[i]); i++;
72 HH(d,a,b,c, W[(3*i+5)%16], 11, tab[i]); i++;
73 HH(c,d,a,b, W[(3*i+5)%16], 16, tab[i]); i++;
74 HH(b,c,d,a, W[(3*i+5)%16], 23, tab[i]); i++;
75 }
76 while (i < 64) {
77 II(a,b,c,d, W[7*i%16], 6, tab[i]); i++;
78 II(d,a,b,c, W[7*i%16], 10, tab[i]); i++;
79 II(c,d,a,b, W[7*i%16], 15, tab[i]); i++;
80 II(b,c,d,a, W[7*i%16], 21, tab[i]); i++;
81 }
82
83 s->h[0] += a;
84 s->h[1] += b;
85 s->h[2] += c;
86 s->h[3] += d;
87 }
88
89 static void pad(struct md5 *s)
90 {
91 unsigned r = s->len % 64;
92
93 s->buf[r++] = 0x80;
94 if (r > 56) {
95 memset(s->buf + r, 0, 64 - r);
96 r = 0;
97 processblock(s, s->buf);
98 }
99 memset(s->buf + r, 0, 56 - r);
100 s->len *= 8;
101 s->buf[56] = s->len;
102 s->buf[57] = s->len >> 8;
103 s->buf[58] = s->len >> 16;
104 s->buf[59] = s->len >> 24;
105 s->buf[60] = s->len >> 32;
106 s->buf[61] = s->len >> 40;
107 s->buf[62] = s->len >> 48;
108 s->buf[63] = s->len >> 56;
109 processblock(s, s->buf);
110 }
111
112 static void md5_init(struct md5 *s)
113 {
114 s->len = 0;
115 s->h[0] = 0x67452301;
116 s->h[1] = 0xefcdab89;
117 s->h[2] = 0x98badcfe;
118 s->h[3] = 0x10325476;
119 }
120
121 static void md5_sum(struct md5 *s, uint8_t *md)
122 {
123 int i;
124
125 pad(s);
126 for (i = 0; i < 4; i++) {
127 md[4*i] = s->h[i];
128 md[4*i+1] = s->h[i] >> 8;
129 md[4*i+2] = s->h[i] >> 16;
130 md[4*i+3] = s->h[i] >> 24;
131 }
132 }
133
134 static void md5_update(struct md5 *s, const void *m, unsigned long len)
135 {
136 const uint8_t *p = m;
137 unsigned r = s->len % 64;
138
139 s->len += len;
140 if (r) {
141 if (len < 64 - r) {
142 memcpy(s->buf + r, p, len);
143 return;
144 }
145 memcpy(s->buf + r, p, 64 - r);
146 len -= 64 - r;
147 p += 64 - r;
148 processblock(s, s->buf);
149 }
150 for (; len >= 64; len -= 64, p += 64)
151 processblock(s, p);
152 memcpy(s->buf, p, len);
153 }
154
155 /*-
156 * Copyright (c) 2003 Poul-Henning Kamp
157 * All rights reserved.
158 *
159 * Redistribution and use in source and binary forms, with or without
160 * modification, are permitted provided that the following conditions
161 * are met:
162 * 1. Redistributions of source code must retain the above copyright
163 * notice, this list of conditions and the following disclaimer.
164 * 2. Redistributions in binary form must reproduce the above copyright
165 * notice, this list of conditions and the following disclaimer in the
166 * documentation and/or other materials provided with the distribution.
167 *
168 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
169 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
170 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
171 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
172 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
173 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
174 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
175 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
176 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
177 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
178 * SUCH DAMAGE.
179 */
180
181 /* key limit is not part of the original design, added for DoS protection */
182 #define KEY_MAX 30000
183 #define SALT_MAX 8
184
185 static const unsigned char b64[] =
186 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
187
188 static char *to64(char *s, unsigned int u, int n)
189 {
190 while (--n >= 0) {
191 *s++ = b64[u % 64];
192 u /= 64;
193 }
194 return s;
195 }
196
197 static char *md5crypt(const char *key, const char *setting, char *output)
198 {
199 struct md5 ctx;
200 unsigned char md[16];
201 unsigned int i, klen, slen;
202 const char *salt;
203 char *p;
204
205 /* reject large keys */
206 klen = strnlen(key, KEY_MAX+1);
207 if (klen > KEY_MAX)
208 return 0;
209
210 /* setting: $1$salt$ (closing $ is optional) */
211 if (strncmp(setting, "$1$", 3) != 0)
212 return 0;
213 salt = setting + 3;
214 for (i = 0; i < SALT_MAX && salt[i] && salt[i] != '$'; i++);
215 slen = i;
216
217 /* md5(key salt key) */
218 md5_init(&ctx);
219 md5_update(&ctx, key, klen);
220 md5_update(&ctx, salt, slen);
221 md5_update(&ctx, key, klen);
222 md5_sum(&ctx, md);
223
224 /* md5(key $1$ salt repeated-md weird-key[0]-0) */
225 md5_init(&ctx);
226 md5_update(&ctx, key, klen);
227 md5_update(&ctx, setting, 3 + slen);
228 for (i = klen; i > sizeof md; i -= sizeof md)
229 md5_update(&ctx, md, sizeof md);
230 md5_update(&ctx, md, i);
231 md[0] = 0;
232 for (i = klen; i; i >>= 1)
233 if (i & 1)
234 md5_update(&ctx, md, 1);
235 else
236 md5_update(&ctx, key, 1);
237 md5_sum(&ctx, md);
238
239 /* md = f(md, key, salt) iteration */
240 for (i = 0; i < 1000; i++) {
241 md5_init(&ctx);
242 if (i % 2)
243 md5_update(&ctx, key, klen);
244 else
245 md5_update(&ctx, md, sizeof md);
246 if (i % 3)
247 md5_update(&ctx, salt, slen);
248 if (i % 7)
249 md5_update(&ctx, key, klen);
250 if (i % 2)
251 md5_update(&ctx, md, sizeof md);
252 else
253 md5_update(&ctx, key, klen);
254 md5_sum(&ctx, md);
255 }
256
257 /* output is $1$salt$hash */
258 memcpy(output, setting, 3 + slen);
259 p = output + 3 + slen;
260 *p++ = '$';
261 static const unsigned char perm[][3] = {
262 0,6,12,1,7,13,2,8,14,3,9,15,4,10,5 };
263 for (i=0; i<5; i++) p = to64(p,
264 (md[perm[i][0]]<<16)|(md[perm[i][1]]<<8)|md[perm[i][2]], 4);
265 p = to64(p, md[11], 2);
266 *p = 0;
267
268 return output;
269 }
270
271 char *__crypt_md5(const char *key, const char *setting, char *output)
272 {
273 static const char testkey[] = "Xy01@#\x01\x02\x80\x7f\xff\r\n\x81\t !";
274 static const char testsetting[] = "$1$abcd0123$";
275 static const char testhash[] = "$1$abcd0123$9Qcg8DyviekV3tDGMZynJ1";
276 char testbuf[64];
277 char *p, *q;
278
279 p = md5crypt(key, setting, output);
280 /* self test and stack cleanup */
281 q = md5crypt(testkey, testsetting, testbuf);
282 if (!p || q != testbuf || memcmp(testbuf, testhash, sizeof testhash))
283 return "*";
284 return p;
285 }
286