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-rw-r--r--src/lib/libc/crypt/md5crypt.c149
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1/* $OpenBSD: md5crypt.c,v 1.15 2009/10/31 13:29:07 sobrado 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 * $FreeBSD: crypt.c,v 1.5 1996/10/14 08:34:02 phk Exp $
12 *
13 */
14
15#include <unistd.h>
16#include <stdio.h>
17#include <string.h>
18#include <md5.h>
19#include <string.h>
20
21static unsigned char itoa64[] = /* 0 ... 63 => ascii - 64 */
22 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
23
24static void to64(char *, u_int32_t, int);
25
26static void
27to64(char *s, u_int32_t v, int n)
28{
29 while (--n >= 0) {
30 *s++ = itoa64[v&0x3f];
31 v >>= 6;
32 }
33}
34
35/*
36 * UNIX password
37 *
38 * Use MD5 for what it is best at...
39 */
40
41char *md5crypt(const char *pw, const char *salt);
42
43char *
44md5crypt(const char *pw, const char *salt)
45{
46 /*
47 * This string is magic for this algorithm. Having
48 * it this way, we can get get better later on
49 */
50 static unsigned char *magic = (unsigned char *)"$1$";
51
52 static char passwd[120], *p;
53 static const unsigned char *sp,*ep;
54 unsigned char final[16];
55 int sl,pl,i;
56 MD5_CTX ctx,ctx1;
57 u_int32_t l;
58
59 /* Refine the Salt first */
60 sp = (const unsigned char *)salt;
61
62 /* If it starts with the magic string, then skip that */
63 if(!strncmp((const char *)sp,(const char *)magic,strlen((const char *)magic)))
64 sp += strlen((const char *)magic);
65
66 /* It stops at the first '$', max 8 chars */
67 for(ep=sp;*ep && *ep != '$' && ep < (sp+8);ep++)
68 continue;
69
70 /* get the length of the true salt */
71 sl = ep - sp;
72
73 MD5Init(&ctx);
74
75 /* The password first, since that is what is most unknown */
76 MD5Update(&ctx,(const unsigned char *)pw,strlen(pw));
77
78 /* Then our magic string */
79 MD5Update(&ctx,magic,strlen((const char *)magic));
80
81 /* Then the raw salt */
82 MD5Update(&ctx,sp,sl);
83
84 /* Then just as many characters of the MD5(pw,salt,pw) */
85 MD5Init(&ctx1);
86 MD5Update(&ctx1,(const unsigned char *)pw,strlen(pw));
87 MD5Update(&ctx1,sp,sl);
88 MD5Update(&ctx1,(const unsigned char *)pw,strlen(pw));
89 MD5Final(final,&ctx1);
90 for(pl = strlen(pw); pl > 0; pl -= 16)
91 MD5Update(&ctx,final,pl>16 ? 16 : pl);
92
93 /* Don't leave anything around in vm they could use. */
94 memset(final,0,sizeof final);
95
96 /* Then something really weird... */
97 for (i = strlen(pw); i ; i >>= 1)
98 if(i&1)
99 MD5Update(&ctx, final, 1);
100 else
101 MD5Update(&ctx, (const unsigned char *)pw, 1);
102
103 /* Now make the output string */
104 snprintf(passwd, sizeof(passwd), "%s%.*s$", (char *)magic,
105 sl, (const char *)sp);
106
107 MD5Final(final,&ctx);
108
109 /*
110 * and now, just to make sure things don't run too fast
111 * On a 60 MHz Pentium this takes 34 msec, so you would
112 * need 30 seconds to build a 1000 entry dictionary...
113 */
114 for(i=0;i<1000;i++) {
115 MD5Init(&ctx1);
116 if(i & 1)
117 MD5Update(&ctx1,(const unsigned char *)pw,strlen(pw));
118 else
119 MD5Update(&ctx1,final,16);
120
121 if(i % 3)
122 MD5Update(&ctx1,sp,sl);
123
124 if(i % 7)
125 MD5Update(&ctx1,(const unsigned char *)pw,strlen(pw));
126
127 if(i & 1)
128 MD5Update(&ctx1,final,16);
129 else
130 MD5Update(&ctx1,(const unsigned char *)pw,strlen(pw));
131 MD5Final(final,&ctx1);
132 }
133
134 p = passwd + strlen(passwd);
135
136 l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; to64(p,l,4); p += 4;
137 l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; to64(p,l,4); p += 4;
138 l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; to64(p,l,4); p += 4;
139 l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; to64(p,l,4); p += 4;
140 l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; to64(p,l,4); p += 4;
141 l = final[11] ; to64(p,l,2); p += 2;
142 *p = '\0';
143
144 /* Don't leave anything around in vm they could use. */
145 memset(final, 0, sizeof final);
146
147 return passwd;
148}
149