1 /*- 2 * Copyright (c) 2003 Poul-Henning Kamp 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/types.h> 31 32 #include <err.h> 33 #include <md5.h> 34 #include <stdio.h> 35 #include <string.h> 36 #include <unistd.h> 37 38 #include "crypt.h" 39 40 /* 41 * UNIX password 42 */ 43 44 char * 45 crypt_md5(const char *pw, const char *salt) 46 { 47 MD5_CTX ctx,ctx1; 48 unsigned long l; 49 int sl, pl; 50 u_int i; 51 u_char final[MD5_SIZE]; 52 static const char *sp, *ep; 53 static char passwd[120], *p; 54 static const char *magic = "$1$"; 55 56 /* Refine the Salt first */ 57 sp = salt; 58 59 /* If it starts with the magic string, then skip that */ 60 if(!strncmp(sp, magic, strlen(magic))) 61 sp += strlen(magic); 62 63 /* It stops at the first '$', max 8 chars */ 64 for(ep = sp; *ep && *ep != '$' && ep < (sp + 8); ep++) 65 continue; 66 67 /* get the length of the true salt */ 68 sl = ep - sp; 69 70 MD5Init(&ctx); 71 72 /* The password first, since that is what is most unknown */ 73 MD5Update(&ctx, (const u_char *)pw, strlen(pw)); 74 75 /* Then our magic string */ 76 MD5Update(&ctx, (const u_char *)magic, strlen(magic)); 77 78 /* Then the raw salt */ 79 MD5Update(&ctx, (const u_char *)sp, (u_int)sl); 80 81 /* Then just as many characters of the MD5(pw,salt,pw) */ 82 MD5Init(&ctx1); 83 MD5Update(&ctx1, (const u_char *)pw, strlen(pw)); 84 MD5Update(&ctx1, (const u_char *)sp, (u_int)sl); 85 MD5Update(&ctx1, (const u_char *)pw, strlen(pw)); 86 MD5Final(final, &ctx1); 87 for(pl = (int)strlen(pw); pl > 0; pl -= MD5_SIZE) 88 MD5Update(&ctx, (const u_char *)final, 89 (u_int)(pl > MD5_SIZE ? MD5_SIZE : pl)); 90 91 /* Don't leave anything around in vm they could use. */ 92 memset(final, 0, sizeof(final)); 93 94 /* Then something really weird... */ 95 for (i = strlen(pw); i; i >>= 1) 96 if(i & 1) 97 MD5Update(&ctx, (const u_char *)final, 1); 98 else 99 MD5Update(&ctx, (const u_char *)pw, 1); 100 101 /* Now make the output string */ 102 strcpy(passwd, magic); 103 strncat(passwd, sp, (u_int)sl); 104 strcat(passwd, "$"); 105 106 MD5Final(final, &ctx); 107 108 /* 109 * and now, just to make sure things don't run too fast 110 * On a 60 Mhz Pentium this takes 34 msec, so you would 111 * need 30 seconds to build a 1000 entry dictionary... 112 */ 113 for(i = 0; i < 1000; i++) { 114 MD5Init(&ctx1); 115 if(i & 1) 116 MD5Update(&ctx1, (const u_char *)pw, strlen(pw)); 117 else 118 MD5Update(&ctx1, (const u_char *)final, MD5_SIZE); 119 120 if(i % 3) 121 MD5Update(&ctx1, (const u_char *)sp, (u_int)sl); 122 123 if(i % 7) 124 MD5Update(&ctx1, (const u_char *)pw, strlen(pw)); 125 126 if(i & 1) 127 MD5Update(&ctx1, (const u_char *)final, MD5_SIZE); 128 else 129 MD5Update(&ctx1, (const u_char *)pw, strlen(pw)); 130 MD5Final(final, &ctx1); 131 } 132 133 p = passwd + strlen(passwd); 134 135 l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; 136 _crypt_to64(p, l, 4); p += 4; 137 l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; 138 _crypt_to64(p, l, 4); p += 4; 139 l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; 140 _crypt_to64(p, l, 4); p += 4; 141 l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; 142 _crypt_to64(p, l, 4); p += 4; 143 l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; 144 _crypt_to64(p, l, 4); p += 4; 145 l = final[11]; 146 _crypt_to64(p, l, 2); p += 2; 147 *p = '\0'; 148 149 /* Don't leave anything around in vm they could use. */ 150 memset(final, 0, sizeof(final)); 151 152 return (passwd); 153 } 154