1 | /*
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2 | * md5 crypt implementation
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3 | *
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4 | * original md5 crypt design is from Poul-Henning Kamp
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5 | * this implementation was created based on the code in freebsd
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6 | * at least 32bit int is assumed, key is limited and $1$ prefix is mandatory,
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7 | * on error "*" is returned
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8 | */
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9 | #include <string.h>
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10 | #include <stdint.h>
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11 |
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12 | /* public domain md5 implementation based on rfc1321 and libtomcrypt */
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13 |
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14 | struct md5 {
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15 | uint64_t len; /* processed message length */
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16 | uint32_t h[4]; /* hash state */
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17 | uint8_t buf[64]; /* message block buffer */
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18 | };
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19 |
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20 | static uint32_t rol(uint32_t n, int k) { return (n << k) | (n >> (32-k)); }
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21 | #define F(x,y,z) (z ^ (x & (y ^ z)))
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22 | #define G(x,y,z) (y ^ (z & (y ^ x)))
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23 | #define H(x,y,z) (x ^ y ^ z)
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24 | #define I(x,y,z) (y ^ (x | ~z))
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25 | #define FF(a,b,c,d,w,s,t) a += F(b,c,d) + w + t; a = rol(a,s) + b
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26 | #define GG(a,b,c,d,w,s,t) a += G(b,c,d) + w + t; a = rol(a,s) + b
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27 | #define HH(a,b,c,d,w,s,t) a += H(b,c,d) + w + t; a = rol(a,s) + b
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28 | #define II(a,b,c,d,w,s,t) a += I(b,c,d) + w + t; a = rol(a,s) + b
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29 |
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30 | static const uint32_t tab[64] = {
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31 | 0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
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32 | 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
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33 | 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, 0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
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34 | 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
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35 | 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
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36 | 0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
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37 | 0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
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38 | 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1, 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391
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39 | };
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40 |
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41 | static void processblock(struct md5 *s, const uint8_t *buf)
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42 | {
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43 | uint32_t i, W[16], a, b, c, d;
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44 |
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45 | for (i = 0; i < 16; i++) {
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46 | W[i] = buf[4*i];
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47 | W[i] |= (uint32_t)buf[4*i+1]<<8;
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48 | W[i] |= (uint32_t)buf[4*i+2]<<16;
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49 | W[i] |= (uint32_t)buf[4*i+3]<<24;
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50 | }
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51 |
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52 | a = s->h[0];
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53 | b = s->h[1];
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54 | c = s->h[2];
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55 | d = s->h[3];
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56 |
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57 | i = 0;
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58 | while (i < 16) {
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59 | FF(a,b,c,d, W[i], 7, tab[i]); i++;
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60 | FF(d,a,b,c, W[i], 12, tab[i]); i++;
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61 | FF(c,d,a,b, W[i], 17, tab[i]); i++;
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62 | FF(b,c,d,a, W[i], 22, tab[i]); i++;
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63 | }
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64 | while (i < 32) {
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65 | GG(a,b,c,d, W[(5*i+1)%16], 5, tab[i]); i++;
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66 | GG(d,a,b,c, W[(5*i+1)%16], 9, tab[i]); i++;
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67 | GG(c,d,a,b, W[(5*i+1)%16], 14, tab[i]); i++;
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68 | GG(b,c,d,a, W[(5*i+1)%16], 20, tab[i]); i++;
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69 | }
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70 | while (i < 48) {
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71 | HH(a,b,c,d, W[(3*i+5)%16], 4, tab[i]); i++;
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72 | HH(d,a,b,c, W[(3*i+5)%16], 11, tab[i]); i++;
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73 | HH(c,d,a,b, W[(3*i+5)%16], 16, tab[i]); i++;
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74 | HH(b,c,d,a, W[(3*i+5)%16], 23, tab[i]); i++;
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75 | }
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76 | while (i < 64) {
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77 | II(a,b,c,d, W[7*i%16], 6, tab[i]); i++;
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78 | II(d,a,b,c, W[7*i%16], 10, tab[i]); i++;
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79 | II(c,d,a,b, W[7*i%16], 15, tab[i]); i++;
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80 | II(b,c,d,a, W[7*i%16], 21, tab[i]); i++;
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81 | }
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82 |
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83 | s->h[0] += a;
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84 | s->h[1] += b;
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85 | s->h[2] += c;
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86 | s->h[3] += d;
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87 | }
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88 |
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89 | static void pad(struct md5 *s)
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90 | {
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91 | unsigned r = s->len % 64;
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92 |
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93 | s->buf[r++] = 0x80;
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94 | if (r > 56) {
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95 | memset(s->buf + r, 0, 64 - r);
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96 | r = 0;
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97 | processblock(s, s->buf);
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98 | }
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99 | memset(s->buf + r, 0, 56 - r);
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100 | s->len *= 8;
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101 | s->buf[56] = s->len;
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102 | s->buf[57] = s->len >> 8;
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103 | s->buf[58] = s->len >> 16;
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104 | s->buf[59] = s->len >> 24;
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105 | s->buf[60] = s->len >> 32;
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106 | s->buf[61] = s->len >> 40;
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107 | s->buf[62] = s->len >> 48;
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108 | s->buf[63] = s->len >> 56;
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109 | processblock(s, s->buf);
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110 | }
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111 |
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112 | static void md5_init(struct md5 *s)
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113 | {
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114 | s->len = 0;
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115 | s->h[0] = 0x67452301;
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116 | s->h[1] = 0xefcdab89;
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117 | s->h[2] = 0x98badcfe;
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118 | s->h[3] = 0x10325476;
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119 | }
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120 |
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121 | static void md5_sum(struct md5 *s, uint8_t *md)
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122 | {
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123 | int i;
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124 |
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125 | pad(s);
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126 | for (i = 0; i < 4; i++) {
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127 | md[4*i] = s->h[i];
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128 | md[4*i+1] = s->h[i] >> 8;
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129 | md[4*i+2] = s->h[i] >> 16;
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130 | md[4*i+3] = s->h[i] >> 24;
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131 | }
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132 | }
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133 |
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134 | static void md5_update(struct md5 *s, const void *m, unsigned long len)
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135 | {
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136 | const uint8_t *p = m;
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137 | unsigned r = s->len % 64;
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138 |
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139 | s->len += len;
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140 | if (r) {
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141 | if (len < 64 - r) {
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142 | memcpy(s->buf + r, p, len);
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143 | return;
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144 | }
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145 | memcpy(s->buf + r, p, 64 - r);
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146 | len -= 64 - r;
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147 | p += 64 - r;
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148 | processblock(s, s->buf);
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149 | }
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150 | for (; len >= 64; len -= 64, p += 64)
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151 | processblock(s, p);
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152 | memcpy(s->buf, p, len);
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153 | }
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154 |
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155 | /*-
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156 | * Copyright (c) 2003 Poul-Henning Kamp
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157 | * All rights reserved.
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158 | *
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159 | * Redistribution and use in source and binary forms, with or without
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160 | * modification, are permitted provided that the following conditions
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161 | * are met:
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162 | * 1. Redistributions of source code must retain the above copyright
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163 | * notice, this list of conditions and the following disclaimer.
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164 | * 2. Redistributions in binary form must reproduce the above copyright
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165 | * notice, this list of conditions and the following disclaimer in the
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166 | * documentation and/or other materials provided with the distribution.
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167 | *
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168 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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169 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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170 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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171 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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172 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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173 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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174 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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175 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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176 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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177 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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178 | * SUCH DAMAGE.
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179 | */
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180 |
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181 | /* key limit is not part of the original design, added for DoS protection */
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182 | #define KEY_MAX 30000
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183 | #define SALT_MAX 8
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184 |
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185 | static const unsigned char b64[] =
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186 | "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
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187 |
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188 | static char *to64(char *s, unsigned int u, int n)
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189 | {
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190 | while (--n >= 0) {
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191 | *s++ = b64[u % 64];
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192 | u /= 64;
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193 | }
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194 | return s;
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195 | }
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196 |
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197 | static char *md5crypt(const char *key, const char *setting, char *output)
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198 | {
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199 | struct md5 ctx;
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200 | unsigned char md[16];
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201 | unsigned int i, klen, slen;
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202 | const char *salt;
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203 | char *p;
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204 |
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205 | /* reject large keys */
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206 | klen = strnlen(key, KEY_MAX+1);
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207 | if (klen > KEY_MAX)
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208 | return 0;
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209 |
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210 | /* setting: $1$salt$ (closing $ is optional) */
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211 | if (strncmp(setting, "$1$", 3) != 0)
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212 | return 0;
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213 | salt = setting + 3;
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214 | for (i = 0; i < SALT_MAX && salt[i] && salt[i] != '$'; i++);
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215 | slen = i;
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216 |
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217 | /* md5(key salt key) */
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218 | md5_init(&ctx);
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219 | md5_update(&ctx, key, klen);
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220 | md5_update(&ctx, salt, slen);
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221 | md5_update(&ctx, key, klen);
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222 | md5_sum(&ctx, md);
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223 |
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224 | /* md5(key $1$ salt repeated-md weird-key[0]-0) */
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225 | md5_init(&ctx);
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226 | md5_update(&ctx, key, klen);
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227 | md5_update(&ctx, setting, 3 + slen);
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228 | for (i = klen; i > sizeof md; i -= sizeof md)
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229 | md5_update(&ctx, md, sizeof md);
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230 | md5_update(&ctx, md, i);
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231 | md[0] = 0;
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232 | for (i = klen; i; i >>= 1)
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233 | if (i & 1)
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234 | md5_update(&ctx, md, 1);
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235 | else
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236 | md5_update(&ctx, key, 1);
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237 | md5_sum(&ctx, md);
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238 |
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239 | /* md = f(md, key, salt) iteration */
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240 | for (i = 0; i < 1000; i++) {
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241 | md5_init(&ctx);
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242 | if (i % 2)
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243 | md5_update(&ctx, key, klen);
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244 | else
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245 | md5_update(&ctx, md, sizeof md);
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246 | if (i % 3)
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247 | md5_update(&ctx, salt, slen);
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248 | if (i % 7)
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249 | md5_update(&ctx, key, klen);
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250 | if (i % 2)
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251 | md5_update(&ctx, md, sizeof md);
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252 | else
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253 | md5_update(&ctx, key, klen);
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254 | md5_sum(&ctx, md);
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255 | }
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256 |
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257 | /* output is $1$salt$hash */
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258 | memcpy(output, setting, 3 + slen);
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259 | p = output + 3 + slen;
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260 | *p++ = '$';
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261 | static const unsigned char perm[][3] = {
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262 | 0,6,12,1,7,13,2,8,14,3,9,15,4,10,5 };
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263 | for (i=0; i<5; i++) p = to64(p,
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264 | (md[perm[i][0]]<<16)|(md[perm[i][1]]<<8)|md[perm[i][2]], 4);
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265 | p = to64(p, md[11], 2);
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266 | *p = 0;
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267 |
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268 | return output;
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269 | }
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270 |
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271 | char *__crypt_md5(const char *key, const char *setting, char *output)
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272 | {
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273 | static const char testkey[] = "Xy01@#\x01\x02\x80\x7f\xff\r\n\x81\t !";
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274 | static const char testsetting[] = "$1$abcd0123$";
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275 | static const char testhash[] = "$1$abcd0123$9Qcg8DyviekV3tDGMZynJ1";
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276 | char testbuf[64];
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277 | char *p, *q;
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278 |
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279 | p = md5crypt(key, setting, output);
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280 | /* self test and stack cleanup */
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281 | q = md5crypt(testkey, testsetting, testbuf);
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282 | if (!p || q != testbuf || memcmp(testbuf, testhash, sizeof testhash))
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283 | return "*";
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284 | return p;
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285 | }
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