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