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/types.h>
30
31 #include <err.h>
32 #include <md5.h>
33 #include <stdio.h>
34 #include <string.h>
35 #include <strings.h>
36 #include <unistd.h>
37
38 #include "crypt.h"
39
40 /*
41 * UNIX password
42 */
43
44 int
crypt_md5(const char * pw,const char * salt,char * buffer)45 crypt_md5(const char *pw, const char *salt, char *buffer)
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 const char *ep;
53 static const char *magic = "$1$";
54
55 /* If the salt starts with the magic string, skip that. */
56 if (!strncmp(salt, magic, strlen(magic)))
57 salt += strlen(magic);
58
59 /* It stops at the first '$', max 8 chars */
60 for (ep = salt; *ep && *ep != '$' && ep < salt + 8; ep++)
61 continue;
62
63 /* get the length of the true salt */
64 sl = ep - salt;
65
66 MD5Init(&ctx);
67
68 /* The password first, since that is what is most unknown */
69 MD5Update(&ctx, (const u_char *)pw, strlen(pw));
70
71 /* Then our magic string */
72 MD5Update(&ctx, (const u_char *)magic, strlen(magic));
73
74 /* Then the raw salt */
75 MD5Update(&ctx, (const u_char *)salt, (u_int)sl);
76
77 /* Then just as many characters of the MD5(pw,salt,pw) */
78 MD5Init(&ctx1);
79 MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
80 MD5Update(&ctx1, (const u_char *)salt, (u_int)sl);
81 MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
82 MD5Final(final, &ctx1);
83 for(pl = (int)strlen(pw); pl > 0; pl -= MD5_SIZE)
84 MD5Update(&ctx, (const u_char *)final,
85 (u_int)(pl > MD5_SIZE ? MD5_SIZE : pl));
86
87 /* Don't leave anything around in vm they could use. */
88 explicit_bzero(final, sizeof(final));
89
90 /* Then something really weird... */
91 for (i = strlen(pw); i; i >>= 1)
92 if(i & 1)
93 MD5Update(&ctx, (const u_char *)final, 1);
94 else
95 MD5Update(&ctx, (const u_char *)pw, 1);
96
97 /* Now make the output string */
98 buffer = stpcpy(buffer, magic);
99 buffer = stpncpy(buffer, salt, (u_int)sl);
100 *buffer++ = '$';
101
102 MD5Final(final, &ctx);
103
104 /*
105 * and now, just to make sure things don't run too fast
106 * On a 60 Mhz Pentium this takes 34 msec, so you would
107 * need 30 seconds to build a 1000 entry dictionary...
108 */
109 for(i = 0; i < 1000; i++) {
110 MD5Init(&ctx1);
111 if(i & 1)
112 MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
113 else
114 MD5Update(&ctx1, (const u_char *)final, MD5_SIZE);
115
116 if(i % 3)
117 MD5Update(&ctx1, (const u_char *)salt, (u_int)sl);
118
119 if(i % 7)
120 MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
121
122 if(i & 1)
123 MD5Update(&ctx1, (const u_char *)final, MD5_SIZE);
124 else
125 MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
126 MD5Final(final, &ctx1);
127 }
128
129 l = (final[ 0]<<16) | (final[ 6]<<8) | final[12];
130 _crypt_to64(buffer, l, 4); buffer += 4;
131 l = (final[ 1]<<16) | (final[ 7]<<8) | final[13];
132 _crypt_to64(buffer, l, 4); buffer += 4;
133 l = (final[ 2]<<16) | (final[ 8]<<8) | final[14];
134 _crypt_to64(buffer, l, 4); buffer += 4;
135 l = (final[ 3]<<16) | (final[ 9]<<8) | final[15];
136 _crypt_to64(buffer, l, 4); buffer += 4;
137 l = (final[ 4]<<16) | (final[10]<<8) | final[ 5];
138 _crypt_to64(buffer, l, 4); buffer += 4;
139 l = final[11];
140 _crypt_to64(buffer, l, 2); buffer += 2;
141 *buffer = '\0';
142
143 /* Don't leave anything around in vm they could use. */
144 explicit_bzero(final, sizeof(final));
145
146 return (0);
147 }
148