1 | /*
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2 | * public domain sha512 crypt implementation
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3 | *
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4 | * original sha crypt design: http://people.redhat.com/drepper/SHA-crypt.txt
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5 | * in this implementation at least 32bit int is assumed,
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6 | * key length is limited, the $6$ prefix is mandatory, '\n' and ':' is rejected
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7 | * in the salt and rounds= setting must contain a valid iteration count,
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8 | * on error "*" is returned.
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9 | */
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10 | #include <ctype.h>
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11 | #include <stdlib.h>
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12 | #include <stdio.h>
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13 | #include <string.h>
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14 | #include <stdint.h>
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15 |
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16 | /* public domain sha512 implementation based on fips180-3 */
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17 | /* >=2^64 bits messages are not supported (about 2000 peta bytes) */
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18 |
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19 | struct sha512 {
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20 | uint64_t len; /* processed message length */
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21 | uint64_t h[8]; /* hash state */
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22 | uint8_t buf[128]; /* message block buffer */
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23 | };
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24 |
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25 | static uint64_t ror(uint64_t n, int k) { return (n >> k) | (n << (64-k)); }
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26 | #define Ch(x,y,z) (z ^ (x & (y ^ z)))
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27 | #define Maj(x,y,z) ((x & y) | (z & (x | y)))
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28 | #define S0(x) (ror(x,28) ^ ror(x,34) ^ ror(x,39))
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29 | #define S1(x) (ror(x,14) ^ ror(x,18) ^ ror(x,41))
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30 | #define R0(x) (ror(x,1) ^ ror(x,8) ^ (x>>7))
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31 | #define R1(x) (ror(x,19) ^ ror(x,61) ^ (x>>6))
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32 |
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33 | static const uint64_t K[80] = {
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34 | 0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL, 0xb5c0fbcfec4d3b2fULL, 0xe9b5dba58189dbbcULL,
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35 | 0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL, 0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL,
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36 | 0xd807aa98a3030242ULL, 0x12835b0145706fbeULL, 0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
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37 | 0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL, 0x9bdc06a725c71235ULL, 0xc19bf174cf692694ULL,
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38 | 0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL, 0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL,
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39 | 0x2de92c6f592b0275ULL, 0x4a7484aa6ea6e483ULL, 0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
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40 | 0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL, 0xb00327c898fb213fULL, 0xbf597fc7beef0ee4ULL,
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41 | 0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL, 0x06ca6351e003826fULL, 0x142929670a0e6e70ULL,
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42 | 0x27b70a8546d22ffcULL, 0x2e1b21385c26c926ULL, 0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
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43 | 0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL, 0x81c2c92e47edaee6ULL, 0x92722c851482353bULL,
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44 | 0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL, 0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL,
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45 | 0xd192e819d6ef5218ULL, 0xd69906245565a910ULL, 0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
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46 | 0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL, 0x2748774cdf8eeb99ULL, 0x34b0bcb5e19b48a8ULL,
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47 | 0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL, 0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL,
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48 | 0x748f82ee5defb2fcULL, 0x78a5636f43172f60ULL, 0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
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49 | 0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL, 0xbef9a3f7b2c67915ULL, 0xc67178f2e372532bULL,
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50 | 0xca273eceea26619cULL, 0xd186b8c721c0c207ULL, 0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL,
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51 | 0x06f067aa72176fbaULL, 0x0a637dc5a2c898a6ULL, 0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
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52 | 0x28db77f523047d84ULL, 0x32caab7b40c72493ULL, 0x3c9ebe0a15c9bebcULL, 0x431d67c49c100d4cULL,
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53 | 0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL, 0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL
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54 | };
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55 |
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56 | static void processblock(struct sha512 *s, const uint8_t *buf)
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57 | {
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58 | uint64_t W[80], t1, t2, a, b, c, d, e, f, g, h;
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59 | int i;
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60 |
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61 | for (i = 0; i < 16; i++) {
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62 | W[i] = (uint64_t)buf[8*i]<<56;
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63 | W[i] |= (uint64_t)buf[8*i+1]<<48;
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64 | W[i] |= (uint64_t)buf[8*i+2]<<40;
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65 | W[i] |= (uint64_t)buf[8*i+3]<<32;
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66 | W[i] |= (uint64_t)buf[8*i+4]<<24;
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67 | W[i] |= (uint64_t)buf[8*i+5]<<16;
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68 | W[i] |= (uint64_t)buf[8*i+6]<<8;
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69 | W[i] |= buf[8*i+7];
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70 | }
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71 | for (; i < 80; i++)
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72 | W[i] = R1(W[i-2]) + W[i-7] + R0(W[i-15]) + W[i-16];
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73 | a = s->h[0];
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74 | b = s->h[1];
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75 | c = s->h[2];
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76 | d = s->h[3];
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77 | e = s->h[4];
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78 | f = s->h[5];
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79 | g = s->h[6];
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80 | h = s->h[7];
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81 | for (i = 0; i < 80; i++) {
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82 | t1 = h + S1(e) + Ch(e,f,g) + K[i] + W[i];
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83 | t2 = S0(a) + Maj(a,b,c);
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84 | h = g;
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85 | g = f;
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86 | f = e;
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87 | e = d + t1;
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88 | d = c;
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89 | c = b;
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90 | b = a;
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91 | a = t1 + t2;
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92 | }
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93 | s->h[0] += a;
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94 | s->h[1] += b;
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95 | s->h[2] += c;
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96 | s->h[3] += d;
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97 | s->h[4] += e;
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98 | s->h[5] += f;
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99 | s->h[6] += g;
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100 | s->h[7] += h;
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101 | }
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102 |
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103 | static void pad(struct sha512 *s)
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104 | {
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105 | unsigned r = s->len % 128;
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106 |
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107 | s->buf[r++] = 0x80;
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108 | if (r > 112) {
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109 | memset(s->buf + r, 0, 128 - r);
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110 | r = 0;
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111 | processblock(s, s->buf);
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112 | }
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113 | memset(s->buf + r, 0, 120 - r);
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114 | s->len *= 8;
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115 | s->buf[120] = s->len >> 56;
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116 | s->buf[121] = s->len >> 48;
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117 | s->buf[122] = s->len >> 40;
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118 | s->buf[123] = s->len >> 32;
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119 | s->buf[124] = s->len >> 24;
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120 | s->buf[125] = s->len >> 16;
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121 | s->buf[126] = s->len >> 8;
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122 | s->buf[127] = s->len;
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123 | processblock(s, s->buf);
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124 | }
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125 |
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126 | static void sha512_init(struct sha512 *s)
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127 | {
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128 | s->len = 0;
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129 | s->h[0] = 0x6a09e667f3bcc908ULL;
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130 | s->h[1] = 0xbb67ae8584caa73bULL;
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131 | s->h[2] = 0x3c6ef372fe94f82bULL;
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132 | s->h[3] = 0xa54ff53a5f1d36f1ULL;
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133 | s->h[4] = 0x510e527fade682d1ULL;
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134 | s->h[5] = 0x9b05688c2b3e6c1fULL;
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135 | s->h[6] = 0x1f83d9abfb41bd6bULL;
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136 | s->h[7] = 0x5be0cd19137e2179ULL;
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137 | }
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138 |
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139 | static void sha512_sum(struct sha512 *s, uint8_t *md)
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140 | {
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141 | int i;
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142 |
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143 | pad(s);
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144 | for (i = 0; i < 8; i++) {
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145 | md[8*i] = s->h[i] >> 56;
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146 | md[8*i+1] = s->h[i] >> 48;
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147 | md[8*i+2] = s->h[i] >> 40;
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148 | md[8*i+3] = s->h[i] >> 32;
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149 | md[8*i+4] = s->h[i] >> 24;
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150 | md[8*i+5] = s->h[i] >> 16;
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151 | md[8*i+6] = s->h[i] >> 8;
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152 | md[8*i+7] = s->h[i];
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153 | }
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154 | }
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155 |
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156 | static void sha512_update(struct sha512 *s, const void *m, unsigned long len)
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157 | {
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158 | const uint8_t *p = m;
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159 | unsigned r = s->len % 128;
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160 |
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161 | s->len += len;
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162 | if (r) {
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163 | if (len < 128 - r) {
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164 | memcpy(s->buf + r, p, len);
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165 | return;
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166 | }
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167 | memcpy(s->buf + r, p, 128 - r);
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168 | len -= 128 - r;
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169 | p += 128 - r;
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170 | processblock(s, s->buf);
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171 | }
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172 | for (; len >= 128; len -= 128, p += 128)
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173 | processblock(s, p);
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174 | memcpy(s->buf, p, len);
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175 | }
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176 |
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177 | static const unsigned char b64[] =
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178 | "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
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179 |
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180 | static char *to64(char *s, unsigned int u, int n)
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181 | {
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182 | while (--n >= 0) {
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183 | *s++ = b64[u % 64];
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184 | u /= 64;
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185 | }
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186 | return s;
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187 | }
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188 |
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189 | /* key limit is not part of the original design, added for DoS protection.
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190 | * rounds limit has been lowered (versus the reference/spec), also for DoS
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191 | * protection. runtime is O(klen^2 + klen*rounds) */
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192 | #define KEY_MAX 256
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193 | #define SALT_MAX 16
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194 | #define ROUNDS_DEFAULT 5000
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195 | #define ROUNDS_MIN 1000
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196 | #define ROUNDS_MAX 9999999
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197 |
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198 | /* hash n bytes of the repeated md message digest */
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199 | static void hashmd(struct sha512 *s, unsigned int n, const void *md)
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200 | {
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201 | unsigned int i;
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202 |
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203 | for (i = n; i > 64; i -= 64)
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204 | sha512_update(s, md, 64);
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205 | sha512_update(s, md, i);
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206 | }
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207 |
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208 | static char *sha512crypt(const char *key, const char *setting, char *output)
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209 | {
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210 | struct sha512 ctx;
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211 | unsigned char md[64], kmd[64], smd[64];
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212 | unsigned int i, r, klen, slen;
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213 | char rounds[20] = "";
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214 | const char *salt;
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215 | char *p;
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216 |
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217 | /* reject large keys */
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218 | for (i = 0; i <= KEY_MAX && key[i]; i++);
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219 | if (i > KEY_MAX)
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220 | return 0;
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221 | klen = i;
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222 |
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223 | /* setting: $6$rounds=n$salt$ (rounds=n$ and closing $ are optional) */
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224 | if (strncmp(setting, "$6$", 3) != 0)
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225 | return 0;
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226 | salt = setting + 3;
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227 |
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228 | r = ROUNDS_DEFAULT;
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229 | if (strncmp(salt, "rounds=", sizeof "rounds=" - 1) == 0) {
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230 | unsigned long u;
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231 | char *end;
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232 |
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233 | /*
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234 | * this is a deviation from the reference:
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235 | * bad rounds setting is rejected if it is
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236 | * - empty
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237 | * - unterminated (missing '$')
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238 | * - begins with anything but a decimal digit
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239 | * the reference implementation treats these bad
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240 | * rounds as part of the salt or parse them with
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241 | * strtoul semantics which may cause problems
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242 | * including non-portable hashes that depend on
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243 | * the host's value of ULONG_MAX.
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244 | */
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245 | salt += sizeof "rounds=" - 1;
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246 | if (!isdigit(*salt))
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247 | return 0;
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248 | u = strtoul(salt, &end, 10);
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249 | if (*end != '$')
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250 | return 0;
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251 | salt = end+1;
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252 | if (u < ROUNDS_MIN)
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253 | r = ROUNDS_MIN;
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254 | else if (u > ROUNDS_MAX)
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255 | return 0;
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256 | else
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257 | r = u;
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258 | /* needed when rounds is zero prefixed or out of bounds */
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259 | sprintf(rounds, "rounds=%u$", r);
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260 | }
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261 |
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262 | for (i = 0; i < SALT_MAX && salt[i] && salt[i] != '$'; i++)
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263 | /* reject characters that interfere with /etc/shadow parsing */
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264 | if (salt[i] == '\n' || salt[i] == ':')
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265 | return 0;
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266 | slen = i;
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267 |
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268 | /* B = sha(key salt key) */
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269 | sha512_init(&ctx);
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270 | sha512_update(&ctx, key, klen);
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271 | sha512_update(&ctx, salt, slen);
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272 | sha512_update(&ctx, key, klen);
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273 | sha512_sum(&ctx, md);
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274 |
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275 | /* A = sha(key salt repeat-B alternate-B-key) */
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276 | sha512_init(&ctx);
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277 | sha512_update(&ctx, key, klen);
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278 | sha512_update(&ctx, salt, slen);
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279 | hashmd(&ctx, klen, md);
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280 | for (i = klen; i > 0; i >>= 1)
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281 | if (i & 1)
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282 | sha512_update(&ctx, md, sizeof md);
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283 | else
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284 | sha512_update(&ctx, key, klen);
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285 | sha512_sum(&ctx, md);
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286 |
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287 | /* DP = sha(repeat-key), this step takes O(klen^2) time */
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288 | sha512_init(&ctx);
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289 | for (i = 0; i < klen; i++)
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290 | sha512_update(&ctx, key, klen);
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291 | sha512_sum(&ctx, kmd);
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292 |
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293 | /* DS = sha(repeat-salt) */
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294 | sha512_init(&ctx);
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295 | for (i = 0; i < 16 + md[0]; i++)
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296 | sha512_update(&ctx, salt, slen);
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297 | sha512_sum(&ctx, smd);
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298 |
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299 | /* iterate A = f(A,DP,DS), this step takes O(rounds*klen) time */
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300 | for (i = 0; i < r; i++) {
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301 | sha512_init(&ctx);
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302 | if (i % 2)
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303 | hashmd(&ctx, klen, kmd);
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304 | else
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305 | sha512_update(&ctx, md, sizeof md);
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306 | if (i % 3)
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307 | sha512_update(&ctx, smd, slen);
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308 | if (i % 7)
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309 | hashmd(&ctx, klen, kmd);
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310 | if (i % 2)
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311 | sha512_update(&ctx, md, sizeof md);
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312 | else
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313 | hashmd(&ctx, klen, kmd);
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314 | sha512_sum(&ctx, md);
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315 | }
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316 |
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317 | /* output is $6$rounds=n$salt$hash */
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318 | p = output;
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319 | p += sprintf(p, "$6$%s%.*s$", rounds, slen, salt);
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320 | #if 1
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321 | static const unsigned char perm[][3] = {
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322 | 0,21,42,22,43,1,44,2,23,3,24,45,25,46,4,
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323 | 47,5,26,6,27,48,28,49,7,50,8,29,9,30,51,
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324 | 31,52,10,53,11,32,12,33,54,34,55,13,56,14,35,
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325 | 15,36,57,37,58,16,59,17,38,18,39,60,40,61,19,
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326 | 62,20,41 };
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327 | for (i=0; i<21; i++) p = to64(p,
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328 | (md[perm[i][0]]<<16)|(md[perm[i][1]]<<8)|md[perm[i][2]], 4);
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329 | #else
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330 | p = to64(p, (md[0]<<16)|(md[21]<<8)|md[42], 4);
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331 | p = to64(p, (md[22]<<16)|(md[43]<<8)|md[1], 4);
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332 | p = to64(p, (md[44]<<16)|(md[2]<<8)|md[23], 4);
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333 | p = to64(p, (md[3]<<16)|(md[24]<<8)|md[45], 4);
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334 | p = to64(p, (md[25]<<16)|(md[46]<<8)|md[4], 4);
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335 | p = to64(p, (md[47]<<16)|(md[5]<<8)|md[26], 4);
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336 | p = to64(p, (md[6]<<16)|(md[27]<<8)|md[48], 4);
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337 | p = to64(p, (md[28]<<16)|(md[49]<<8)|md[7], 4);
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338 | p = to64(p, (md[50]<<16)|(md[8]<<8)|md[29], 4);
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339 | p = to64(p, (md[9]<<16)|(md[30]<<8)|md[51], 4);
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340 | p = to64(p, (md[31]<<16)|(md[52]<<8)|md[10], 4);
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341 | p = to64(p, (md[53]<<16)|(md[11]<<8)|md[32], 4);
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342 | p = to64(p, (md[12]<<16)|(md[33]<<8)|md[54], 4);
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343 | p = to64(p, (md[34]<<16)|(md[55]<<8)|md[13], 4);
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344 | p = to64(p, (md[56]<<16)|(md[14]<<8)|md[35], 4);
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345 | p = to64(p, (md[15]<<16)|(md[36]<<8)|md[57], 4);
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346 | p = to64(p, (md[37]<<16)|(md[58]<<8)|md[16], 4);
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347 | p = to64(p, (md[59]<<16)|(md[17]<<8)|md[38], 4);
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348 | p = to64(p, (md[18]<<16)|(md[39]<<8)|md[60], 4);
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349 | p = to64(p, (md[40]<<16)|(md[61]<<8)|md[19], 4);
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350 | p = to64(p, (md[62]<<16)|(md[20]<<8)|md[41], 4);
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351 | #endif
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352 | p = to64(p, md[63], 2);
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353 | *p = 0;
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354 | return output;
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355 | }
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356 |
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357 | char *__crypt_sha512(const char *key, const char *setting, char *output)
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358 | {
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359 | static const char testkey[] = "Xy01@#\x01\x02\x80\x7f\xff\r\n\x81\t !";
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360 | static const char testsetting[] = "$6$rounds=1234$abc0123456789$";
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361 | static const char testhash[] = "$6$rounds=1234$abc0123456789$BCpt8zLrc/RcyuXmCDOE1ALqMXB2MH6n1g891HhFj8.w7LxGv.FTkqq6Vxc/km3Y0jE0j24jY5PIv/oOu6reg1";
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362 | char testbuf[128];
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363 | char *p, *q;
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364 |
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365 | p = sha512crypt(key, setting, output);
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366 | /* self test and stack cleanup */
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367 | q = sha512crypt(testkey, testsetting, testbuf);
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368 | if (!p || q != testbuf || memcmp(testbuf, testhash, sizeof testhash))
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369 | return "*";
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370 | return p;
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371 | }
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