1 /*-
2 * Copyright (c) 2003 Poul-Henning Kamp
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29
30 #include <sys/types.h>
31
32 #include <err.h>
33 #include <md5.h>
34 #include <stdio.h>
35 #include <string.h>
36 #include <unistd.h>
37
38 #include "crypt.h"
39
40 /*
41 * UNIX password
42 */
43
44 char *
crypt_md5(const char * pw,const char * salt)45 crypt_md5(const char *pw, const char *salt)
46 {
47 MD5_CTX ctx,ctx1;
48 unsigned long l;
49 int sl, pl;
50 u_int i;
51 u_char final[MD5_SIZE];
52 static const char *sp, *ep;
53 static char passwd[120], *p;
54 static const char *magic = "$1$";
55
56 /* Refine the Salt first */
57 sp = salt;
58
59 /* If it starts with the magic string, then skip that */
60 if(!strncmp(sp, magic, strlen(magic)))
61 sp += strlen(magic);
62
63 /* It stops at the first '$', max 8 chars */
64 for(ep = sp; *ep && *ep != '$' && ep < (sp + 8); ep++)
65 continue;
66
67 /* get the length of the true salt */
68 sl = ep - sp;
69
70 MD5Init(&ctx);
71
72 /* The password first, since that is what is most unknown */
73 MD5Update(&ctx, (const u_char *)pw, strlen(pw));
74
75 /* Then our magic string */
76 MD5Update(&ctx, (const u_char *)magic, strlen(magic));
77
78 /* Then the raw salt */
79 MD5Update(&ctx, (const u_char *)sp, (u_int)sl);
80
81 /* Then just as many characters of the MD5(pw,salt,pw) */
82 MD5Init(&ctx1);
83 MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
84 MD5Update(&ctx1, (const u_char *)sp, (u_int)sl);
85 MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
86 MD5Final(final, &ctx1);
87 for(pl = (int)strlen(pw); pl > 0; pl -= MD5_SIZE)
88 MD5Update(&ctx, (const u_char *)final,
89 (u_int)(pl > MD5_SIZE ? MD5_SIZE : pl));
90
91 /* Don't leave anything around in vm they could use. */
92 memset(final, 0, sizeof(final));
93
94 /* Then something really weird... */
95 for (i = strlen(pw); i; i >>= 1)
96 if(i & 1)
97 MD5Update(&ctx, (const u_char *)final, 1);
98 else
99 MD5Update(&ctx, (const u_char *)pw, 1);
100
101 /* Now make the output string */
102 strcpy(passwd, magic);
103 strncat(passwd, sp, (u_int)sl);
104 strcat(passwd, "$");
105
106 MD5Final(final, &ctx);
107
108 /*
109 * and now, just to make sure things don't run too fast
110 * On a 60 Mhz Pentium this takes 34 msec, so you would
111 * need 30 seconds to build a 1000 entry dictionary...
112 */
113 for(i = 0; i < 1000; i++) {
114 MD5Init(&ctx1);
115 if(i & 1)
116 MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
117 else
118 MD5Update(&ctx1, (const u_char *)final, MD5_SIZE);
119
120 if(i % 3)
121 MD5Update(&ctx1, (const u_char *)sp, (u_int)sl);
122
123 if(i % 7)
124 MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
125
126 if(i & 1)
127 MD5Update(&ctx1, (const u_char *)final, MD5_SIZE);
128 else
129 MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
130 MD5Final(final, &ctx1);
131 }
132
133 p = passwd + strlen(passwd);
134
135 l = (final[ 0]<<16) | (final[ 6]<<8) | final[12];
136 _crypt_to64(p, l, 4); p += 4;
137 l = (final[ 1]<<16) | (final[ 7]<<8) | final[13];
138 _crypt_to64(p, l, 4); p += 4;
139 l = (final[ 2]<<16) | (final[ 8]<<8) | final[14];
140 _crypt_to64(p, l, 4); p += 4;
141 l = (final[ 3]<<16) | (final[ 9]<<8) | final[15];
142 _crypt_to64(p, l, 4); p += 4;
143 l = (final[ 4]<<16) | (final[10]<<8) | final[ 5];
144 _crypt_to64(p, l, 4); p += 4;
145 l = final[11];
146 _crypt_to64(p, l, 2); p += 2;
147 *p = '\0';
148
149 /* Don't leave anything around in vm they could use. */
150 memset(final, 0, sizeof(final));
151
152 return (passwd);
153 }
154