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 <inttypes.h> 28 #include <md5.h> 29 #include <string.h> 30 31 /* 32 * UNIX password 33 */ 34 35 static char *_crypt_to64(char *s, uint32_t v, int n) 36 { 37 static const char itoa64[64] = "./0123456789" 38 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; 39 40 while (--n >= 0) { 41 *s++ = itoa64[v & 0x3f]; 42 v >>= 6; 43 } 44 return s; 45 } 46 47 char *crypt_md5(const char *pw, const char *salt) 48 { 49 MD5_CTX ctx, ctx1; 50 unsigned long l; 51 int sl, pl; 52 uint32_t i; 53 uint8_t final[MD5_SIZE]; 54 const char *sp; 55 static char passwd[120]; /* Output buffer */ 56 static const char magic[] = "$1$"; 57 char *p; 58 const int magic_len = sizeof magic - 1; 59 int pwlen = strlen(pw); 60 61 /* Refine the Salt first */ 62 sp = salt; 63 64 /* If it starts with the magic string, then skip that */ 65 if (!strncmp(sp, magic, magic_len)) 66 sp += magic_len; 67 68 /* Compute the salt length: 69 it stops at the first '$', max 8 chars */ 70 for (sl = 0; sl < 8 && sp[sl] && sp[sl] != '$'; sl++) ; 71 72 MD5Init(&ctx); 73 74 /* The password first, since that is what is most unknown */ 75 MD5Update(&ctx, pw, pwlen); 76 77 /* Then our magic string */ 78 MD5Update(&ctx, magic, magic_len); 79 80 /* Then the raw salt */ 81 MD5Update(&ctx, sp, sl); 82 83 /* Then just as many characters of the MD5(pw,salt,pw) */ 84 MD5Init(&ctx1); 85 MD5Update(&ctx1, pw, pwlen); 86 MD5Update(&ctx1, sp, sl); 87 MD5Update(&ctx1, pw, pwlen); 88 MD5Final(final, &ctx1); 89 for (pl = pwlen; pl > 0; pl -= MD5_SIZE) 90 MD5Update(&ctx, final, pl > MD5_SIZE ? MD5_SIZE : pl); 91 92 /* Don't leave anything around in vm they could use. */ 93 memset(final, 0, sizeof final); 94 95 /* Then something really weird... */ 96 for (i = pwlen; i; i >>= 1) 97 if (i & 1) 98 MD5Update(&ctx, final, 1); 99 else 100 MD5Update(&ctx, pw, 1); 101 102 /* Now make the output string */ 103 p = passwd; 104 105 memcpy(p, magic, magic_len); 106 p += magic_len; 107 108 memcpy(p, sp, sl); 109 p += sl; 110 111 *p++ = '$'; 112 113 MD5Final(final, &ctx); 114 115 /* 116 * and now, just to make sure things don't run too fast 117 * On a 60 Mhz Pentium this takes 34 msec, so you would 118 * need 30 seconds to build a 1000 entry dictionary... 119 */ 120 for (i = 0; i < 1000; i++) { 121 MD5Init(&ctx1); 122 if (i & 1) 123 MD5Update(&ctx1, pw, pwlen); 124 else 125 MD5Update(&ctx1, final, MD5_SIZE); 126 127 if (i % 3) 128 MD5Update(&ctx1, sp, sl); 129 130 if (i % 7) 131 MD5Update(&ctx1, pw, pwlen); 132 133 if (i & 1) 134 MD5Update(&ctx1, final, MD5_SIZE); 135 else 136 MD5Update(&ctx1, pw, pwlen); 137 MD5Final(final, &ctx1); 138 } 139 140 l = (final[0] << 16) | (final[6] << 8) | final[12]; 141 p = _crypt_to64(p, l, 4); 142 l = (final[1] << 16) | (final[7] << 8) | final[13]; 143 p = _crypt_to64(p, l, 4); 144 l = (final[2] << 16) | (final[8] << 8) | final[14]; 145 p = _crypt_to64(p, l, 4); 146 l = (final[3] << 16) | (final[9] << 8) | final[15]; 147 p = _crypt_to64(p, l, 4); 148 l = (final[4] << 16) | (final[10] << 8) | final[5]; 149 p = _crypt_to64(p, l, 4); 150 l = final[11]; 151 p = _crypt_to64(p, l, 2); 152 *p = '\0'; 153 154 /* Don't leave anything around in vm they could use. */ 155 memset(final, 0, sizeof final); 156 157 return passwd; 158 } 159 160 #ifdef TEST 161 #include <stdio.h> 162 163 int main(int argc, char *argv[]) 164 { 165 int i; 166 167 for (i = 2; i < argc; i += 2) { 168 puts(crypt_md5(argv[i], argv[i - 1])); 169 } 170 return 0; 171 } 172 173 #endif 174
