1 /* $NetBSD: md5crypt.c,v 1.14 2013/08/28 17:47:07 riastradh Exp $ */
2
3 /*
4 * ----------------------------------------------------------------------------
5 * "THE BEER-WARE LICENSE" (Revision 42):
6 * <phk@login.dknet.dk> wrote this file. As long as you retain this notice you
7 * can do whatever you want with this stuff. If we meet some day, and you think
8 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
9 * ----------------------------------------------------------------------------
10 *
11 * from FreeBSD: crypt.c,v 1.5 1996/10/14 08:34:02 phk Exp
12 * via OpenBSD: md5crypt.c,v 1.9 1997/07/23 20:58:27 kstailey Exp
13 *
14 */
15
16 #include <sys/cdefs.h>
17 #if !defined(lint)
18 __RCSID("$NetBSD: md5crypt.c,v 1.14 2013/08/28 17:47:07 riastradh Exp $");
19 #endif /* not lint */
20
21 #include <unistd.h>
22 #include <stdio.h>
23 #include <string.h>
24 #include <md5.h>
25
26 #include "crypt.h"
27
28 #define MD5_MAGIC "$1$"
29 #define MD5_MAGIC_LEN 3
30
31 #define INIT(x) MD5Init((x))
32 #define UPDATE(x, b, l) MD5Update((x), (b), (l))
33 #define FINAL(v, x) MD5Final((v), (x))
34
35
36 /*
37 * MD5 password encryption.
38 */
39 char *
__md5crypt(const char * pw,const char * salt)40 __md5crypt(const char *pw, const char *salt)
41 {
42 static char passwd[120], *p;
43 const char *sp, *ep;
44 unsigned char final[16];
45 unsigned int i, sl, pwl;
46 MD5_CTX ctx, ctx1;
47 u_int32_t l;
48 int pl;
49
50 pwl = strlen(pw);
51
52 /* Refine the salt first */
53 sp = salt;
54
55 /* If it starts with the magic string, then skip that */
56 if (strncmp(sp, MD5_MAGIC, MD5_MAGIC_LEN) == 0)
57 sp += MD5_MAGIC_LEN;
58
59 /* It stops at the first '$', max 8 chars */
60 for (ep = sp; *ep != '\0' && *ep != '$' && ep < (sp + 8); ep++)
61 continue;
62
63 /* get the length of the true salt */
64 sl = ep - sp;
65
66 INIT(&ctx);
67
68 /* The password first, since that is what is most unknown */
69 UPDATE(&ctx, (const unsigned char *)pw, pwl);
70
71 /* Then our magic string */
72 UPDATE(&ctx, (const unsigned char *)MD5_MAGIC, MD5_MAGIC_LEN);
73
74 /* Then the raw salt */
75 UPDATE(&ctx, (const unsigned char *)sp, sl);
76
77 /* Then just as many characters of the MD5(pw,salt,pw) */
78 INIT(&ctx1);
79 UPDATE(&ctx1, (const unsigned char *)pw, pwl);
80 UPDATE(&ctx1, (const unsigned char *)sp, sl);
81 UPDATE(&ctx1, (const unsigned char *)pw, pwl);
82 FINAL(final, &ctx1);
83
84 for (pl = pwl; pl > 0; pl -= 16)
85 UPDATE(&ctx, final, (unsigned int)(pl > 16 ? 16 : pl));
86
87 /* Don't leave anything around in vm they could use. */
88 memset(final, 0, sizeof(final));
89
90 /* Then something really weird... */
91 for (i = pwl; i != 0; i >>= 1)
92 if ((i & 1) != 0)
93 UPDATE(&ctx, final, 1);
94 else
95 UPDATE(&ctx, (const unsigned char *)pw, 1);
96
97 /* Now make the output string */
98 memcpy(passwd, MD5_MAGIC, MD5_MAGIC_LEN);
99 strlcpy(passwd + MD5_MAGIC_LEN, sp, sl + 1);
100 strlcat(passwd, "$", sizeof(passwd));
101
102 FINAL(final, &ctx);
103
104 /* memset(&ctx, 0, sizeof(ctx)); done by MD5Final() */
105
106 /*
107 * And now, just to make sure things don't run too fast. On a 60 MHz
108 * Pentium this takes 34 msec, so you would need 30 seconds to build
109 * a 1000 entry dictionary...
110 */
111 for (i = 0; i < 1000; i++) {
112 INIT(&ctx1);
113
114 if ((i & 1) != 0)
115 UPDATE(&ctx1, (const unsigned char *)pw, pwl);
116 else
117 UPDATE(&ctx1, final, 16);
118
119 if ((i % 3) != 0)
120 UPDATE(&ctx1, (const unsigned char *)sp, sl);
121
122 if ((i % 7) != 0)
123 UPDATE(&ctx1, (const unsigned char *)pw, pwl);
124
125 if ((i & 1) != 0)
126 UPDATE(&ctx1, final, 16);
127 else
128 UPDATE(&ctx1, (const unsigned char *)pw, pwl);
129
130 FINAL(final, &ctx1);
131 }
132
133 /* memset(&ctx1, 0, sizeof(ctx1)); done by MD5Final() */
134
135 p = passwd + sl + MD5_MAGIC_LEN + 1;
136
137 l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; __crypt_to64(p,l,4); p += 4;
138 l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; __crypt_to64(p,l,4); p += 4;
139 l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; __crypt_to64(p,l,4); p += 4;
140 l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; __crypt_to64(p,l,4); p += 4;
141 l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; __crypt_to64(p,l,4); p += 4;
142 l = final[11] ; __crypt_to64(p,l,2); p += 2;
143 *p = '\0';
144
145 /* Don't leave anything around in vm they could use. */
146 explicit_memset(final, 0, sizeof(final));
147 return (passwd);
148 }
149