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