How buggy this little piece of code could be? Repair strnvis() buffersize
[dragonfly.git] / lib / libcrypt / crypt-md5.c
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1/*
2 * ----------------------------------------------------------------------------
3 * "THE BEER-WARE LICENSE" (Revision 42):
4 * <phk@login.dknet.dk> wrote this file. As long as you retain this notice you
5 * can do whatever you want with this stuff. If we meet some day, and you think
6 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
7 * ----------------------------------------------------------------------------
8 *
9 * $FreeBSD: src/lib/libcrypt/crypt-md5.c,v 1.5.2.1 2001/05/24 12:20:02 markm Exp $
2c3b12ff 10 * $DragonFly: src/lib/libcrypt/crypt-md5.c,v 1.3 2005/08/04 17:27:09 drhodus Exp $
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11 */
12
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13#include <unistd.h>
14#include <stdio.h>
15#include <string.h>
16#include <md5.h>
17#include <err.h>
18#include "crypt.h"
19
20/*
21 * UNIX password
22 */
23
24char *
2c3b12ff 25crypt_md5(const char *pw, const char *salt)
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26{
27 static char *magic = "$1$"; /*
28 * This string is magic for
29 * this algorithm. Having
30 * it this way, we can get
31 * get better later on
32 */
33 static char passwd[120], *p;
34 static const char *sp,*ep;
35 unsigned char final[MD5_SIZE];
36 int sl,pl,i;
37 MD5_CTX ctx,ctx1;
38 unsigned long l;
39
40 /* Refine the Salt first */
41 sp = salt;
42
43 /* If it starts with the magic string, then skip that */
44 if(!strncmp(sp,magic,strlen(magic)))
45 sp += strlen(magic);
46
47 /* It stops at the first '$', max 8 chars */
48 for(ep=sp;*ep && *ep != '$' && ep < (sp+8);ep++)
49 continue;
50
51 /* get the length of the true salt */
52 sl = ep - sp;
53
54 MD5Init(&ctx);
55
56 /* The password first, since that is what is most unknown */
57 MD5Update(&ctx,pw,strlen(pw));
58
59 /* Then our magic string */
60 MD5Update(&ctx,magic,strlen(magic));
61
62 /* Then the raw salt */
63 MD5Update(&ctx,sp,sl);
64
65 /* Then just as many characters of the MD5(pw,salt,pw) */
66 MD5Init(&ctx1);
67 MD5Update(&ctx1,pw,strlen(pw));
68 MD5Update(&ctx1,sp,sl);
69 MD5Update(&ctx1,pw,strlen(pw));
70 MD5Final(final,&ctx1);
71 for(pl = strlen(pw); pl > 0; pl -= MD5_SIZE)
72 MD5Update(&ctx,final,pl>MD5_SIZE ? MD5_SIZE : pl);
73
74 /* Don't leave anything around in vm they could use. */
75 memset(final,0,sizeof final);
76
77 /* Then something really weird... */
78 for (i = strlen(pw); i ; i >>= 1)
79 if(i&1)
80 MD5Update(&ctx, final, 1);
81 else
82 MD5Update(&ctx, pw, 1);
83
84 /* Now make the output string */
85 strcpy(passwd,magic);
86 strncat(passwd,sp,sl);
87 strcat(passwd,"$");
88
89 MD5Final(final,&ctx);
90
91 /*
92 * and now, just to make sure things don't run too fast
93 * On a 60 Mhz Pentium this takes 34 msec, so you would
94 * need 30 seconds to build a 1000 entry dictionary...
95 */
96 for(i=0;i<1000;i++) {
97 MD5Init(&ctx1);
98 if(i & 1)
99 MD5Update(&ctx1,pw,strlen(pw));
100 else
101 MD5Update(&ctx1,final,MD5_SIZE);
102
103 if(i % 3)
104 MD5Update(&ctx1,sp,sl);
105
106 if(i % 7)
107 MD5Update(&ctx1,pw,strlen(pw));
108
109 if(i & 1)
110 MD5Update(&ctx1,final,MD5_SIZE);
111 else
112 MD5Update(&ctx1,pw,strlen(pw));
113 MD5Final(final,&ctx1);
114 }
115
116 p = passwd + strlen(passwd);
117
118 l = (final[ 0]<<16) | (final[ 6]<<8) | final[12];
119 _crypt_to64(p,l,4); p += 4;
120 l = (final[ 1]<<16) | (final[ 7]<<8) | final[13];
121 _crypt_to64(p,l,4); p += 4;
122 l = (final[ 2]<<16) | (final[ 8]<<8) | final[14];
123 _crypt_to64(p,l,4); p += 4;
124 l = (final[ 3]<<16) | (final[ 9]<<8) | final[15];
125 _crypt_to64(p,l,4); p += 4;
126 l = (final[ 4]<<16) | (final[10]<<8) | final[ 5];
127 _crypt_to64(p,l,4); p += 4;
128 l = final[11] ;
129 _crypt_to64(p,l,2); p += 2;
130 *p = '\0';
131
132 /* Don't leave anything around in vm they could use. */
133 memset(final,0,sizeof final);
134
135 return passwd;
136}
137