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 * $FreeBSD$ 10 * 11 */ 12 13 #if defined(LIBC_SCCS) && !defined(lint) 14 static const char rcsid[] = \ 15 "$FreeBSD$"; 16 #endif /* LIBC_SCCS and not lint */ 17 18 #include <unistd.h> 19 #include <stdio.h> 20 #include <string.h> 21 #include <md5.h> 22 #include <err.h> 23 #include "crypt.h" 24 25 /* 26 * UNIX password 27 */ 28 29 char * 30 crypt_md5(pw, salt) 31 const char *pw; 32 const char *salt; 33 { 34 static char *magic = "$1$"; /* 35 * This string is magic for 36 * this algorithm. Having 37 * it this way, we can get 38 * get better later on 39 */ 40 static char passwd[120], *p; 41 static const char *sp,*ep; 42 unsigned char final[MD5_SIZE]; 43 int sl,pl,i; 44 MD5_CTX ctx,ctx1; 45 unsigned long l; 46 47 /* Refine the Salt first */ 48 sp = salt; 49 50 /* If it starts with the magic string, then skip that */ 51 if(!strncmp(sp,magic,strlen(magic))) 52 sp += strlen(magic); 53 54 /* It stops at the first '$', max 8 chars */ 55 for(ep=sp;*ep && *ep != '$' && ep < (sp+8);ep++) 56 continue; 57 58 /* get the length of the true salt */ 59 sl = ep - sp; 60 61 MD5Init(&ctx); 62 63 /* The password first, since that is what is most unknown */ 64 MD5Update(&ctx,pw,strlen(pw)); 65 66 /* Then our magic string */ 67 MD5Update(&ctx,magic,strlen(magic)); 68 69 /* Then the raw salt */ 70 MD5Update(&ctx,sp,sl); 71 72 /* Then just as many characters of the MD5(pw,salt,pw) */ 73 MD5Init(&ctx1); 74 MD5Update(&ctx1,pw,strlen(pw)); 75 MD5Update(&ctx1,sp,sl); 76 MD5Update(&ctx1,pw,strlen(pw)); 77 MD5Final(final,&ctx1); 78 for(pl = strlen(pw); pl > 0; pl -= MD5_SIZE) 79 MD5Update(&ctx,final,pl>MD5_SIZE ? MD5_SIZE : pl); 80 81 /* Don't leave anything around in vm they could use. */ 82 memset(final,0,sizeof final); 83 84 /* Then something really weird... */ 85 for (i = strlen(pw); i ; i >>= 1) 86 if(i&1) 87 MD5Update(&ctx, final, 1); 88 else 89 MD5Update(&ctx, pw, 1); 90 91 /* Now make the output string */ 92 strcpy(passwd,magic); 93 strncat(passwd,sp,sl); 94 strcat(passwd,"$"); 95 96 MD5Final(final,&ctx); 97 98 /* 99 * and now, just to make sure things don't run too fast 100 * On a 60 Mhz Pentium this takes 34 msec, so you would 101 * need 30 seconds to build a 1000 entry dictionary... 102 */ 103 for(i=0;i<1000;i++) { 104 MD5Init(&ctx1); 105 if(i & 1) 106 MD5Update(&ctx1,pw,strlen(pw)); 107 else 108 MD5Update(&ctx1,final,MD5_SIZE); 109 110 if(i % 3) 111 MD5Update(&ctx1,sp,sl); 112 113 if(i % 7) 114 MD5Update(&ctx1,pw,strlen(pw)); 115 116 if(i & 1) 117 MD5Update(&ctx1,final,MD5_SIZE); 118 else 119 MD5Update(&ctx1,pw,strlen(pw)); 120 MD5Final(final,&ctx1); 121 } 122 123 p = passwd + strlen(passwd); 124 125 l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; 126 _crypt_to64(p,l,4); p += 4; 127 l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; 128 _crypt_to64(p,l,4); p += 4; 129 l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; 130 _crypt_to64(p,l,4); p += 4; 131 l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; 132 _crypt_to64(p,l,4); p += 4; 133 l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; 134 _crypt_to64(p,l,4); p += 4; 135 l = final[11] ; 136 _crypt_to64(p,l,2); p += 2; 137 *p = '\0'; 138 139 /* Don't leave anything around in vm they could use. */ 140 memset(final,0,sizeof final); 141 142 return passwd; 143 } 144 145