| 1 | /* |
| 2 | * SHA-256 algorithm as described at |
| 3 | * |
| 4 | * http://csrc.nist.gov/cryptval/shs.html |
| 5 | */ |
| 6 | |
| 7 | #include "ssh.h" |
| 8 | |
| 9 | /* ---------------------------------------------------------------------- |
| 10 | * Core SHA256 algorithm: processes 16-word blocks into a message digest. |
| 11 | */ |
| 12 | |
| 13 | #define ror(x,y) ( ((x) << (32-y)) | (((uint32)(x)) >> (y)) ) |
| 14 | #define shr(x,y) ( (((uint32)(x)) >> (y)) ) |
| 15 | #define Ch(x,y,z) ( ((x) & (y)) ^ (~(x) & (z)) ) |
| 16 | #define Maj(x,y,z) ( ((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)) ) |
| 17 | #define bigsigma0(x) ( ror((x),2) ^ ror((x),13) ^ ror((x),22) ) |
| 18 | #define bigsigma1(x) ( ror((x),6) ^ ror((x),11) ^ ror((x),25) ) |
| 19 | #define smallsigma0(x) ( ror((x),7) ^ ror((x),18) ^ shr((x),3) ) |
| 20 | #define smallsigma1(x) ( ror((x),17) ^ ror((x),19) ^ shr((x),10) ) |
| 21 | |
| 22 | void SHA256_Core_Init(SHA256_State *s) { |
| 23 | s->h[0] = 0x6a09e667; |
| 24 | s->h[1] = 0xbb67ae85; |
| 25 | s->h[2] = 0x3c6ef372; |
| 26 | s->h[3] = 0xa54ff53a; |
| 27 | s->h[4] = 0x510e527f; |
| 28 | s->h[5] = 0x9b05688c; |
| 29 | s->h[6] = 0x1f83d9ab; |
| 30 | s->h[7] = 0x5be0cd19; |
| 31 | } |
| 32 | |
| 33 | void SHA256_Block(SHA256_State *s, uint32 *block) { |
| 34 | uint32 w[80]; |
| 35 | uint32 a,b,c,d,e,f,g,h; |
| 36 | static const int k[] = { |
| 37 | 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, |
| 38 | 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5, |
| 39 | 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, |
| 40 | 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, |
| 41 | 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, |
| 42 | 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, |
| 43 | 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, |
| 44 | 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, |
| 45 | 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, |
| 46 | 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, |
| 47 | 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, |
| 48 | 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, |
| 49 | 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, |
| 50 | 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3, |
| 51 | 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, |
| 52 | 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2, |
| 53 | }; |
| 54 | |
| 55 | int t; |
| 56 | |
| 57 | for (t = 0; t < 16; t++) |
| 58 | w[t] = block[t]; |
| 59 | |
| 60 | for (t = 16; t < 64; t++) |
| 61 | w[t] = smallsigma1(w[t-2]) + w[t-7] + smallsigma0(w[t-15]) + w[t-16]; |
| 62 | |
| 63 | a = s->h[0]; b = s->h[1]; c = s->h[2]; d = s->h[3]; |
| 64 | e = s->h[4]; f = s->h[5]; g = s->h[6]; h = s->h[7]; |
| 65 | |
| 66 | for (t = 0; t < 64; t+=8) { |
| 67 | uint32 t1, t2; |
| 68 | |
| 69 | #define ROUND(j,a,b,c,d,e,f,g,h) \ |
| 70 | t1 = h + bigsigma1(e) + Ch(e,f,g) + k[j] + w[j]; \ |
| 71 | t2 = bigsigma0(a) + Maj(a,b,c); \ |
| 72 | d = d + t1; h = t1 + t2; |
| 73 | |
| 74 | ROUND(t+0, a,b,c,d,e,f,g,h); |
| 75 | ROUND(t+1, h,a,b,c,d,e,f,g); |
| 76 | ROUND(t+2, g,h,a,b,c,d,e,f); |
| 77 | ROUND(t+3, f,g,h,a,b,c,d,e); |
| 78 | ROUND(t+4, e,f,g,h,a,b,c,d); |
| 79 | ROUND(t+5, d,e,f,g,h,a,b,c); |
| 80 | ROUND(t+6, c,d,e,f,g,h,a,b); |
| 81 | ROUND(t+7, b,c,d,e,f,g,h,a); |
| 82 | } |
| 83 | |
| 84 | s->h[0] += a; s->h[1] += b; s->h[2] += c; s->h[3] += d; |
| 85 | s->h[4] += e; s->h[5] += f; s->h[6] += g; s->h[7] += h; |
| 86 | } |
| 87 | |
| 88 | /* ---------------------------------------------------------------------- |
| 89 | * Outer SHA256 algorithm: take an arbitrary length byte string, |
| 90 | * convert it into 16-word blocks with the prescribed padding at |
| 91 | * the end, and pass those blocks to the core SHA256 algorithm. |
| 92 | */ |
| 93 | |
| 94 | #define BLKSIZE 64 |
| 95 | |
| 96 | void SHA256_Init(SHA256_State *s) { |
| 97 | SHA256_Core_Init(s); |
| 98 | s->blkused = 0; |
| 99 | s->lenhi = s->lenlo = 0; |
| 100 | } |
| 101 | |
| 102 | void SHA256_Bytes(SHA256_State *s, const void *p, int len) { |
| 103 | unsigned char *q = (unsigned char *)p; |
| 104 | uint32 wordblock[16]; |
| 105 | uint32 lenw = len; |
| 106 | int i; |
| 107 | |
| 108 | /* |
| 109 | * Update the length field. |
| 110 | */ |
| 111 | s->lenlo += lenw; |
| 112 | s->lenhi += (s->lenlo < lenw); |
| 113 | |
| 114 | if (s->blkused && s->blkused+len < BLKSIZE) { |
| 115 | /* |
| 116 | * Trivial case: just add to the block. |
| 117 | */ |
| 118 | memcpy(s->block + s->blkused, q, len); |
| 119 | s->blkused += len; |
| 120 | } else { |
| 121 | /* |
| 122 | * We must complete and process at least one block. |
| 123 | */ |
| 124 | while (s->blkused + len >= BLKSIZE) { |
| 125 | memcpy(s->block + s->blkused, q, BLKSIZE - s->blkused); |
| 126 | q += BLKSIZE - s->blkused; |
| 127 | len -= BLKSIZE - s->blkused; |
| 128 | /* Now process the block. Gather bytes big-endian into words */ |
| 129 | for (i = 0; i < 16; i++) { |
| 130 | wordblock[i] = |
| 131 | ( ((uint32)s->block[i*4+0]) << 24 ) | |
| 132 | ( ((uint32)s->block[i*4+1]) << 16 ) | |
| 133 | ( ((uint32)s->block[i*4+2]) << 8 ) | |
| 134 | ( ((uint32)s->block[i*4+3]) << 0 ); |
| 135 | } |
| 136 | SHA256_Block(s, wordblock); |
| 137 | s->blkused = 0; |
| 138 | } |
| 139 | memcpy(s->block, q, len); |
| 140 | s->blkused = len; |
| 141 | } |
| 142 | } |
| 143 | |
| 144 | void SHA256_Final(SHA256_State *s, unsigned char *digest) { |
| 145 | int i; |
| 146 | int pad; |
| 147 | unsigned char c[64]; |
| 148 | uint32 lenhi, lenlo; |
| 149 | |
| 150 | if (s->blkused >= 56) |
| 151 | pad = 56 + 64 - s->blkused; |
| 152 | else |
| 153 | pad = 56 - s->blkused; |
| 154 | |
| 155 | lenhi = (s->lenhi << 3) | (s->lenlo >> (32-3)); |
| 156 | lenlo = (s->lenlo << 3); |
| 157 | |
| 158 | memset(c, 0, pad); |
| 159 | c[0] = 0x80; |
| 160 | SHA256_Bytes(s, &c, pad); |
| 161 | |
| 162 | c[0] = (lenhi >> 24) & 0xFF; |
| 163 | c[1] = (lenhi >> 16) & 0xFF; |
| 164 | c[2] = (lenhi >> 8) & 0xFF; |
| 165 | c[3] = (lenhi >> 0) & 0xFF; |
| 166 | c[4] = (lenlo >> 24) & 0xFF; |
| 167 | c[5] = (lenlo >> 16) & 0xFF; |
| 168 | c[6] = (lenlo >> 8) & 0xFF; |
| 169 | c[7] = (lenlo >> 0) & 0xFF; |
| 170 | |
| 171 | SHA256_Bytes(s, &c, 8); |
| 172 | |
| 173 | for (i = 0; i < 8; i++) { |
| 174 | digest[i*4+0] = (s->h[i] >> 24) & 0xFF; |
| 175 | digest[i*4+1] = (s->h[i] >> 16) & 0xFF; |
| 176 | digest[i*4+2] = (s->h[i] >> 8) & 0xFF; |
| 177 | digest[i*4+3] = (s->h[i] >> 0) & 0xFF; |
| 178 | } |
| 179 | } |
| 180 | |
| 181 | void SHA256_Simple(const void *p, int len, unsigned char *output) { |
| 182 | SHA256_State s; |
| 183 | |
| 184 | SHA256_Init(&s); |
| 185 | SHA256_Bytes(&s, p, len); |
| 186 | SHA256_Final(&s, output); |
| 187 | } |
| 188 | |
| 189 | /* |
| 190 | * Thin abstraction for things where hashes are pluggable. |
| 191 | */ |
| 192 | |
| 193 | static void *sha256_init(void) |
| 194 | { |
| 195 | SHA256_State *s; |
| 196 | |
| 197 | s = snew(SHA256_State); |
| 198 | SHA256_Init(s); |
| 199 | return s; |
| 200 | } |
| 201 | |
| 202 | static void sha256_bytes(void *handle, void *p, int len) |
| 203 | { |
| 204 | SHA256_State *s = handle; |
| 205 | |
| 206 | SHA256_Bytes(s, p, len); |
| 207 | } |
| 208 | |
| 209 | static void sha256_final(void *handle, unsigned char *output) |
| 210 | { |
| 211 | SHA256_State *s = handle; |
| 212 | |
| 213 | SHA256_Final(s, output); |
| 214 | sfree(s); |
| 215 | } |
| 216 | |
| 217 | const struct ssh_hash ssh_sha256 = { |
| 218 | sha256_init, sha256_bytes, sha256_final, 32 |
| 219 | }; |
| 220 | |
| 221 | #ifdef TEST |
| 222 | |
| 223 | #include <stdio.h> |
| 224 | #include <stdlib.h> |
| 225 | #include <assert.h> |
| 226 | |
| 227 | int main(void) { |
| 228 | unsigned char digest[32]; |
| 229 | int i, j, errors; |
| 230 | |
| 231 | struct { |
| 232 | const char *teststring; |
| 233 | unsigned char digest[32]; |
| 234 | } tests[] = { |
| 235 | { "abc", { |
| 236 | 0xba, 0x78, 0x16, 0xbf, 0x8f, 0x01, 0xcf, 0xea, |
| 237 | 0x41, 0x41, 0x40, 0xde, 0x5d, 0xae, 0x22, 0x23, |
| 238 | 0xb0, 0x03, 0x61, 0xa3, 0x96, 0x17, 0x7a, 0x9c, |
| 239 | 0xb4, 0x10, 0xff, 0x61, 0xf2, 0x00, 0x15, 0xad, |
| 240 | } }, |
| 241 | { "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq", { |
| 242 | 0x24, 0x8d, 0x6a, 0x61, 0xd2, 0x06, 0x38, 0xb8, |
| 243 | 0xe5, 0xc0, 0x26, 0x93, 0x0c, 0x3e, 0x60, 0x39, |
| 244 | 0xa3, 0x3c, 0xe4, 0x59, 0x64, 0xff, 0x21, 0x67, |
| 245 | 0xf6, 0xec, 0xed, 0xd4, 0x19, 0xdb, 0x06, 0xc1, |
| 246 | } }, |
| 247 | }; |
| 248 | |
| 249 | errors = 0; |
| 250 | |
| 251 | for (i = 0; i < sizeof(tests) / sizeof(*tests); i++) { |
| 252 | SHA256_Simple(tests[i].teststring, |
| 253 | strlen(tests[i].teststring), digest); |
| 254 | for (j = 0; j < 32; j++) { |
| 255 | if (digest[j] != tests[i].digest[j]) { |
| 256 | fprintf(stderr, |
| 257 | "\"%s\" digest byte %d should be 0x%02x, is 0x%02x\n", |
| 258 | tests[i].teststring, j, tests[i].digest[j], digest[j]); |
| 259 | errors++; |
| 260 | } |
| 261 | } |
| 262 | } |
| 263 | |
| 264 | printf("%d errors\n", errors); |
| 265 | |
| 266 | return 0; |
| 267 | } |
| 268 | |
| 269 | #endif |