aboutsummaryrefslogtreecommitdiff
path: root/lib/libcrypt/crypt-md5.c
blob: 7088267634459e584bdb91a1af52215fb2afe018 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 2003 Poul-Henning Kamp
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/types.h>

#include <err.h>
#include <md5.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include "crypt.h"

/*
 * UNIX password
 */

int
crypt_md5(const char *pw, const char *salt, char *buffer)
{
	MD5_CTX	ctx,ctx1;
	unsigned long l;
	int sl, pl;
	u_int i;
	u_char final[MD5_SIZE];
	const char *ep;
	static const char *magic = "$1$";

	/* If the salt starts with the magic string, skip that. */
	if (!strncmp(salt, magic, strlen(magic)))
		salt += strlen(magic);

	/* It stops at the first '$', max 8 chars */
	for (ep = salt; *ep && *ep != '$' && ep < salt + 8; ep++)
		continue;

	/* get the length of the true salt */
	sl = ep - salt;

	MD5Init(&ctx);

	/* The password first, since that is what is most unknown */
	MD5Update(&ctx, (const u_char *)pw, strlen(pw));

	/* Then our magic string */
	MD5Update(&ctx, (const u_char *)magic, strlen(magic));

	/* Then the raw salt */
	MD5Update(&ctx, (const u_char *)salt, (u_int)sl);

	/* Then just as many characters of the MD5(pw,salt,pw) */
	MD5Init(&ctx1);
	MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
	MD5Update(&ctx1, (const u_char *)salt, (u_int)sl);
	MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
	MD5Final(final, &ctx1);
	for(pl = (int)strlen(pw); pl > 0; pl -= MD5_SIZE)
		MD5Update(&ctx, (const u_char *)final,
		    (u_int)(pl > MD5_SIZE ? MD5_SIZE : pl));

	/* Don't leave anything around in vm they could use. */
	memset(final, 0, sizeof(final));

	/* Then something really weird... */
	for (i = strlen(pw); i; i >>= 1)
		if(i & 1)
		    MD5Update(&ctx, (const u_char *)final, 1);
		else
		    MD5Update(&ctx, (const u_char *)pw, 1);

	/* Now make the output string */
	buffer = stpcpy(buffer, magic);
	buffer = stpncpy(buffer, salt, (u_int)sl);
	*buffer++ = '$';

	MD5Final(final, &ctx);

	/*
	 * and now, just to make sure things don't run too fast
	 * On a 60 Mhz Pentium this takes 34 msec, so you would
	 * need 30 seconds to build a 1000 entry dictionary...
	 */
	for(i = 0; i < 1000; i++) {
		MD5Init(&ctx1);
		if(i & 1)
			MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
		else
			MD5Update(&ctx1, (const u_char *)final, MD5_SIZE);

		if(i % 3)
			MD5Update(&ctx1, (const u_char *)salt, (u_int)sl);

		if(i % 7)
			MD5Update(&ctx1, (const u_char *)pw, strlen(pw));

		if(i & 1)
			MD5Update(&ctx1, (const u_char *)final, MD5_SIZE);
		else
			MD5Update(&ctx1, (const u_char *)pw, strlen(pw));
		MD5Final(final, &ctx1);
	}

	l = (final[ 0]<<16) | (final[ 6]<<8) | final[12];
	_crypt_to64(buffer, l, 4); buffer += 4;
	l = (final[ 1]<<16) | (final[ 7]<<8) | final[13];
	_crypt_to64(buffer, l, 4); buffer += 4;
	l = (final[ 2]<<16) | (final[ 8]<<8) | final[14];
	_crypt_to64(buffer, l, 4); buffer += 4;
	l = (final[ 3]<<16) | (final[ 9]<<8) | final[15];
	_crypt_to64(buffer, l, 4); buffer += 4;
	l = (final[ 4]<<16) | (final[10]<<8) | final[ 5];
	_crypt_to64(buffer, l, 4); buffer += 4;
	l = final[11];
	_crypt_to64(buffer, l, 2); buffer += 2;
	*buffer = '\0';

	/* Don't leave anything around in vm they could use. */
	memset(final, 0, sizeof(final));

	return (0);
}