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
150
151
152
153
154
155
156
157
|
/*
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <phk@login.dknet.dk> wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
* ----------------------------------------------------------------------------
*
* $Id: crypt.c,v 1.4 1996/07/12 18:56:01 jkh Exp $
*
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] = "$Header: /home/ncvs/src/lib/libcrypt/crypt.c,v 1.4 1996/07/12 18:56:01 jkh Exp $";
#endif /* LIBC_SCCS and not lint */
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <md5.h>
#include <string.h>
static unsigned char itoa64[] = /* 0 ... 63 => ascii - 64 */
"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
static void to64 __P((char *, unsigned long, int));
static void
to64(s, v, n)
char *s;
unsigned long v;
int n;
{
static void to64 __P((char *, unsigned long, int));
while (--n >= 0) {
*s++ = itoa64[v&0x3f];
v >>= 6;
}
}
/*
* UNIX password
*
* Use MD5 for what it is best at...
*/
char *
crypt(pw, salt)
register const char *pw;
register const char *salt;
{
static char *magic = "$1$"; /*
* This string is magic for
* this algorithm. Having
* it this way, we can get
* get better later on
*/
static char passwd[120], *p;
static const char *sp,*ep;
unsigned char final[16];
int sl,pl,i,j;
MD5_CTX ctx,ctx1;
unsigned long l;
/* Refine the Salt first */
sp = salt;
/* If it starts with the magic string, then skip that */
if(!strncmp(sp,magic,strlen(magic)))
sp += strlen(magic);
/* It stops at the first '$', max 8 chars */
for(ep=sp;*ep && *ep != '$' && ep < (sp+8);ep++)
continue;
/* get the length of the true salt */
sl = ep - sp;
MD5Init(&ctx);
/* The password first, since that is what is most unknown */
MD5Update(&ctx,pw,strlen(pw));
/* Then our magic string */
MD5Update(&ctx,magic,strlen(magic));
/* Then the raw salt */
MD5Update(&ctx,sp,sl);
/* Then just as many characters of the MD5(pw,salt,pw) */
MD5Init(&ctx1);
MD5Update(&ctx1,pw,strlen(pw));
MD5Update(&ctx1,sp,sl);
MD5Update(&ctx1,pw,strlen(pw));
MD5Final(final,&ctx1);
for(pl = strlen(pw); pl > 0; pl -= 16)
MD5Update(&ctx,final,pl>16 ? 16 : 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, final, 1);
else
MD5Update(&ctx, pw, 1);
/* Now make the output string */
strcpy(passwd,magic);
strncat(passwd,sp,sl);
strcat(passwd,"$");
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,pw,strlen(pw));
else
MD5Update(&ctx1,final,16);
if(i % 3)
MD5Update(&ctx1,sp,sl);
if(i % 7)
MD5Update(&ctx1,pw,strlen(pw));
if(i & 1)
MD5Update(&ctx1,final,16);
else
MD5Update(&ctx1,pw,strlen(pw));
MD5Final(final,&ctx1);
}
p = passwd + strlen(passwd);
l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; to64(p,l,4); p += 4;
l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; to64(p,l,4); p += 4;
l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; to64(p,l,4); p += 4;
l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; to64(p,l,4); p += 4;
l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; to64(p,l,4); p += 4;
l = final[11] ; to64(p,l,2); p += 2;
*p = '\0';
/* Don't leave anything around in vm they could use. */
memset(final,0,sizeof final);
return passwd;
}
|
