| 1 | /* |
| 2 | * SHA1 hash algorithm. Used in SSH-2 as a MAC, and the transform is |
| 3 | * also used as a `stirring' function for the PuTTY random number |
| 4 | * pool. Implemented directly from the specification by Simon |
| 5 | * Tatham. |
| 6 | */ |
| 7 | |
| 8 | #include "ssh.h" |
| 9 | |
| 10 | /* ---------------------------------------------------------------------- |
| 11 | * Core SHA algorithm: processes 16-word blocks into a message digest. |
| 12 | */ |
| 13 | |
| 14 | #define rol(x,y) ( ((x) << (y)) | (((uint32)x) >> (32-y)) ) |
| 15 | |
| 16 | static void SHA_Core_Init(uint32 h[5]) |
| 17 | { |
| 18 | h[0] = 0x67452301; |
| 19 | h[1] = 0xefcdab89; |
| 20 | h[2] = 0x98badcfe; |
| 21 | h[3] = 0x10325476; |
| 22 | h[4] = 0xc3d2e1f0; |
| 23 | } |
| 24 | |
| 25 | void SHATransform(word32 * digest, word32 * block) |
| 26 | { |
| 27 | word32 w[80]; |
| 28 | word32 a, b, c, d, e; |
| 29 | int t; |
| 30 | |
| 31 | #ifdef RANDOM_DIAGNOSTICS |
| 32 | { |
| 33 | extern int random_diagnostics; |
| 34 | if (random_diagnostics) { |
| 35 | int i; |
| 36 | printf("SHATransform:"); |
| 37 | for (i = 0; i < 5; i++) |
| 38 | printf(" %08x", digest[i]); |
| 39 | printf(" +"); |
| 40 | for (i = 0; i < 16; i++) |
| 41 | printf(" %08x", block[i]); |
| 42 | } |
| 43 | } |
| 44 | #endif |
| 45 | |
| 46 | for (t = 0; t < 16; t++) |
| 47 | w[t] = block[t]; |
| 48 | |
| 49 | for (t = 16; t < 80; t++) { |
| 50 | word32 tmp = w[t - 3] ^ w[t - 8] ^ w[t - 14] ^ w[t - 16]; |
| 51 | w[t] = rol(tmp, 1); |
| 52 | } |
| 53 | |
| 54 | a = digest[0]; |
| 55 | b = digest[1]; |
| 56 | c = digest[2]; |
| 57 | d = digest[3]; |
| 58 | e = digest[4]; |
| 59 | |
| 60 | for (t = 0; t < 20; t++) { |
| 61 | word32 tmp = |
| 62 | rol(a, 5) + ((b & c) | (d & ~b)) + e + w[t] + 0x5a827999; |
| 63 | e = d; |
| 64 | d = c; |
| 65 | c = rol(b, 30); |
| 66 | b = a; |
| 67 | a = tmp; |
| 68 | } |
| 69 | for (t = 20; t < 40; t++) { |
| 70 | word32 tmp = rol(a, 5) + (b ^ c ^ d) + e + w[t] + 0x6ed9eba1; |
| 71 | e = d; |
| 72 | d = c; |
| 73 | c = rol(b, 30); |
| 74 | b = a; |
| 75 | a = tmp; |
| 76 | } |
| 77 | for (t = 40; t < 60; t++) { |
| 78 | word32 tmp = rol(a, |
| 79 | 5) + ((b & c) | (b & d) | (c & d)) + e + w[t] + |
| 80 | 0x8f1bbcdc; |
| 81 | e = d; |
| 82 | d = c; |
| 83 | c = rol(b, 30); |
| 84 | b = a; |
| 85 | a = tmp; |
| 86 | } |
| 87 | for (t = 60; t < 80; t++) { |
| 88 | word32 tmp = rol(a, 5) + (b ^ c ^ d) + e + w[t] + 0xca62c1d6; |
| 89 | e = d; |
| 90 | d = c; |
| 91 | c = rol(b, 30); |
| 92 | b = a; |
| 93 | a = tmp; |
| 94 | } |
| 95 | |
| 96 | digest[0] += a; |
| 97 | digest[1] += b; |
| 98 | digest[2] += c; |
| 99 | digest[3] += d; |
| 100 | digest[4] += e; |
| 101 | |
| 102 | #ifdef RANDOM_DIAGNOSTICS |
| 103 | { |
| 104 | extern int random_diagnostics; |
| 105 | if (random_diagnostics) { |
| 106 | int i; |
| 107 | printf(" ="); |
| 108 | for (i = 0; i < 5; i++) |
| 109 | printf(" %08x", digest[i]); |
| 110 | printf("\n"); |
| 111 | } |
| 112 | } |
| 113 | #endif |
| 114 | } |
| 115 | |
| 116 | /* ---------------------------------------------------------------------- |
| 117 | * Outer SHA algorithm: take an arbitrary length byte string, |
| 118 | * convert it into 16-word blocks with the prescribed padding at |
| 119 | * the end, and pass those blocks to the core SHA algorithm. |
| 120 | */ |
| 121 | |
| 122 | void SHA_Init(SHA_State * s) |
| 123 | { |
| 124 | SHA_Core_Init(s->h); |
| 125 | s->blkused = 0; |
| 126 | s->lenhi = s->lenlo = 0; |
| 127 | } |
| 128 | |
| 129 | void SHA_Bytes(SHA_State * s, const void *p, int len) |
| 130 | { |
| 131 | const unsigned char *q = (const unsigned char *) p; |
| 132 | uint32 wordblock[16]; |
| 133 | uint32 lenw = len; |
| 134 | int i; |
| 135 | |
| 136 | /* |
| 137 | * Update the length field. |
| 138 | */ |
| 139 | s->lenlo += lenw; |
| 140 | s->lenhi += (s->lenlo < lenw); |
| 141 | |
| 142 | if (s->blkused && s->blkused + len < 64) { |
| 143 | /* |
| 144 | * Trivial case: just add to the block. |
| 145 | */ |
| 146 | memcpy(s->block + s->blkused, q, len); |
| 147 | s->blkused += len; |
| 148 | } else { |
| 149 | /* |
| 150 | * We must complete and process at least one block. |
| 151 | */ |
| 152 | while (s->blkused + len >= 64) { |
| 153 | memcpy(s->block + s->blkused, q, 64 - s->blkused); |
| 154 | q += 64 - s->blkused; |
| 155 | len -= 64 - s->blkused; |
| 156 | /* Now process the block. Gather bytes big-endian into words */ |
| 157 | for (i = 0; i < 16; i++) { |
| 158 | wordblock[i] = |
| 159 | (((uint32) s->block[i * 4 + 0]) << 24) | |
| 160 | (((uint32) s->block[i * 4 + 1]) << 16) | |
| 161 | (((uint32) s->block[i * 4 + 2]) << 8) | |
| 162 | (((uint32) s->block[i * 4 + 3]) << 0); |
| 163 | } |
| 164 | SHATransform(s->h, wordblock); |
| 165 | s->blkused = 0; |
| 166 | } |
| 167 | memcpy(s->block, q, len); |
| 168 | s->blkused = len; |
| 169 | } |
| 170 | } |
| 171 | |
| 172 | void SHA_Final(SHA_State * s, unsigned char *output) |
| 173 | { |
| 174 | int i; |
| 175 | int pad; |
| 176 | unsigned char c[64]; |
| 177 | uint32 lenhi, lenlo; |
| 178 | |
| 179 | if (s->blkused >= 56) |
| 180 | pad = 56 + 64 - s->blkused; |
| 181 | else |
| 182 | pad = 56 - s->blkused; |
| 183 | |
| 184 | lenhi = (s->lenhi << 3) | (s->lenlo >> (32 - 3)); |
| 185 | lenlo = (s->lenlo << 3); |
| 186 | |
| 187 | memset(c, 0, pad); |
| 188 | c[0] = 0x80; |
| 189 | SHA_Bytes(s, &c, pad); |
| 190 | |
| 191 | c[0] = (lenhi >> 24) & 0xFF; |
| 192 | c[1] = (lenhi >> 16) & 0xFF; |
| 193 | c[2] = (lenhi >> 8) & 0xFF; |
| 194 | c[3] = (lenhi >> 0) & 0xFF; |
| 195 | c[4] = (lenlo >> 24) & 0xFF; |
| 196 | c[5] = (lenlo >> 16) & 0xFF; |
| 197 | c[6] = (lenlo >> 8) & 0xFF; |
| 198 | c[7] = (lenlo >> 0) & 0xFF; |
| 199 | |
| 200 | SHA_Bytes(s, &c, 8); |
| 201 | |
| 202 | for (i = 0; i < 5; i++) { |
| 203 | output[i * 4] = (s->h[i] >> 24) & 0xFF; |
| 204 | output[i * 4 + 1] = (s->h[i] >> 16) & 0xFF; |
| 205 | output[i * 4 + 2] = (s->h[i] >> 8) & 0xFF; |
| 206 | output[i * 4 + 3] = (s->h[i]) & 0xFF; |
| 207 | } |
| 208 | } |
| 209 | |
| 210 | void SHA_Simple(const void *p, int len, unsigned char *output) |
| 211 | { |
| 212 | SHA_State s; |
| 213 | |
| 214 | SHA_Init(&s); |
| 215 | SHA_Bytes(&s, p, len); |
| 216 | SHA_Final(&s, output); |
| 217 | } |
| 218 | |
| 219 | /* |
| 220 | * Thin abstraction for things where hashes are pluggable. |
| 221 | */ |
| 222 | |
| 223 | static void *sha1_init(void) |
| 224 | { |
| 225 | SHA_State *s; |
| 226 | |
| 227 | s = snew(SHA_State); |
| 228 | SHA_Init(s); |
| 229 | return s; |
| 230 | } |
| 231 | |
| 232 | static void sha1_bytes(void *handle, void *p, int len) |
| 233 | { |
| 234 | SHA_State *s = handle; |
| 235 | |
| 236 | SHA_Bytes(s, p, len); |
| 237 | } |
| 238 | |
| 239 | static void sha1_final(void *handle, unsigned char *output) |
| 240 | { |
| 241 | SHA_State *s = handle; |
| 242 | |
| 243 | SHA_Final(s, output); |
| 244 | sfree(s); |
| 245 | } |
| 246 | |
| 247 | const struct ssh_hash ssh_sha1 = { |
| 248 | sha1_init, sha1_bytes, sha1_final, 20, "SHA-1" |
| 249 | }; |
| 250 | |
| 251 | /* ---------------------------------------------------------------------- |
| 252 | * The above is the SHA-1 algorithm itself. Now we implement the |
| 253 | * HMAC wrapper on it. |
| 254 | */ |
| 255 | |
| 256 | static void *sha1_make_context(void) |
| 257 | { |
| 258 | return snewn(3, SHA_State); |
| 259 | } |
| 260 | |
| 261 | static void sha1_free_context(void *handle) |
| 262 | { |
| 263 | sfree(handle); |
| 264 | } |
| 265 | |
| 266 | static void sha1_key_internal(void *handle, unsigned char *key, int len) |
| 267 | { |
| 268 | SHA_State *keys = (SHA_State *)handle; |
| 269 | unsigned char foo[64]; |
| 270 | int i; |
| 271 | |
| 272 | memset(foo, 0x36, 64); |
| 273 | for (i = 0; i < len && i < 64; i++) |
| 274 | foo[i] ^= key[i]; |
| 275 | SHA_Init(&keys[0]); |
| 276 | SHA_Bytes(&keys[0], foo, 64); |
| 277 | |
| 278 | memset(foo, 0x5C, 64); |
| 279 | for (i = 0; i < len && i < 64; i++) |
| 280 | foo[i] ^= key[i]; |
| 281 | SHA_Init(&keys[1]); |
| 282 | SHA_Bytes(&keys[1], foo, 64); |
| 283 | |
| 284 | smemclr(foo, 64); /* burn the evidence */ |
| 285 | } |
| 286 | |
| 287 | static void sha1_key(void *handle, unsigned char *key) |
| 288 | { |
| 289 | sha1_key_internal(handle, key, 20); |
| 290 | } |
| 291 | |
| 292 | static void sha1_key_buggy(void *handle, unsigned char *key) |
| 293 | { |
| 294 | sha1_key_internal(handle, key, 16); |
| 295 | } |
| 296 | |
| 297 | static void hmacsha1_start(void *handle) |
| 298 | { |
| 299 | SHA_State *keys = (SHA_State *)handle; |
| 300 | |
| 301 | keys[2] = keys[0]; /* structure copy */ |
| 302 | } |
| 303 | |
| 304 | static void hmacsha1_bytes(void *handle, unsigned char const *blk, int len) |
| 305 | { |
| 306 | SHA_State *keys = (SHA_State *)handle; |
| 307 | SHA_Bytes(&keys[2], (void *)blk, len); |
| 308 | } |
| 309 | |
| 310 | static void hmacsha1_genresult(void *handle, unsigned char *hmac) |
| 311 | { |
| 312 | SHA_State *keys = (SHA_State *)handle; |
| 313 | SHA_State s; |
| 314 | unsigned char intermediate[20]; |
| 315 | |
| 316 | s = keys[2]; /* structure copy */ |
| 317 | SHA_Final(&s, intermediate); |
| 318 | s = keys[1]; /* structure copy */ |
| 319 | SHA_Bytes(&s, intermediate, 20); |
| 320 | SHA_Final(&s, hmac); |
| 321 | } |
| 322 | |
| 323 | static void sha1_do_hmac(void *handle, unsigned char *blk, int len, |
| 324 | unsigned long seq, unsigned char *hmac) |
| 325 | { |
| 326 | unsigned char seqbuf[4]; |
| 327 | |
| 328 | PUT_32BIT_MSB_FIRST(seqbuf, seq); |
| 329 | hmacsha1_start(handle); |
| 330 | hmacsha1_bytes(handle, seqbuf, 4); |
| 331 | hmacsha1_bytes(handle, blk, len); |
| 332 | hmacsha1_genresult(handle, hmac); |
| 333 | } |
| 334 | |
| 335 | static void sha1_generate(void *handle, unsigned char *blk, int len, |
| 336 | unsigned long seq) |
| 337 | { |
| 338 | sha1_do_hmac(handle, blk, len, seq, blk + len); |
| 339 | } |
| 340 | |
| 341 | static int hmacsha1_verresult(void *handle, unsigned char const *hmac) |
| 342 | { |
| 343 | unsigned char correct[20]; |
| 344 | hmacsha1_genresult(handle, correct); |
| 345 | return !memcmp(correct, hmac, 20); |
| 346 | } |
| 347 | |
| 348 | static int sha1_verify(void *handle, unsigned char *blk, int len, |
| 349 | unsigned long seq) |
| 350 | { |
| 351 | unsigned char correct[20]; |
| 352 | sha1_do_hmac(handle, blk, len, seq, correct); |
| 353 | return !memcmp(correct, blk + len, 20); |
| 354 | } |
| 355 | |
| 356 | static void hmacsha1_96_genresult(void *handle, unsigned char *hmac) |
| 357 | { |
| 358 | unsigned char full[20]; |
| 359 | hmacsha1_genresult(handle, full); |
| 360 | memcpy(hmac, full, 12); |
| 361 | } |
| 362 | |
| 363 | static void sha1_96_generate(void *handle, unsigned char *blk, int len, |
| 364 | unsigned long seq) |
| 365 | { |
| 366 | unsigned char full[20]; |
| 367 | sha1_do_hmac(handle, blk, len, seq, full); |
| 368 | memcpy(blk + len, full, 12); |
| 369 | } |
| 370 | |
| 371 | static int hmacsha1_96_verresult(void *handle, unsigned char const *hmac) |
| 372 | { |
| 373 | unsigned char correct[20]; |
| 374 | hmacsha1_genresult(handle, correct); |
| 375 | return !memcmp(correct, hmac, 12); |
| 376 | } |
| 377 | |
| 378 | static int sha1_96_verify(void *handle, unsigned char *blk, int len, |
| 379 | unsigned long seq) |
| 380 | { |
| 381 | unsigned char correct[20]; |
| 382 | sha1_do_hmac(handle, blk, len, seq, correct); |
| 383 | return !memcmp(correct, blk + len, 12); |
| 384 | } |
| 385 | |
| 386 | void hmac_sha1_simple(void *key, int keylen, void *data, int datalen, |
| 387 | unsigned char *output) { |
| 388 | SHA_State states[2]; |
| 389 | unsigned char intermediate[20]; |
| 390 | |
| 391 | sha1_key_internal(states, key, keylen); |
| 392 | SHA_Bytes(&states[0], data, datalen); |
| 393 | SHA_Final(&states[0], intermediate); |
| 394 | |
| 395 | SHA_Bytes(&states[1], intermediate, 20); |
| 396 | SHA_Final(&states[1], output); |
| 397 | } |
| 398 | |
| 399 | const struct ssh_mac ssh_hmac_sha1 = { |
| 400 | sha1_make_context, sha1_free_context, sha1_key, |
| 401 | sha1_generate, sha1_verify, |
| 402 | hmacsha1_start, hmacsha1_bytes, hmacsha1_genresult, hmacsha1_verresult, |
| 403 | "hmac-sha1", |
| 404 | 20, |
| 405 | "HMAC-SHA1" |
| 406 | }; |
| 407 | |
| 408 | const struct ssh_mac ssh_hmac_sha1_96 = { |
| 409 | sha1_make_context, sha1_free_context, sha1_key, |
| 410 | sha1_96_generate, sha1_96_verify, |
| 411 | hmacsha1_start, hmacsha1_bytes, |
| 412 | hmacsha1_96_genresult, hmacsha1_96_verresult, |
| 413 | "hmac-sha1-96", |
| 414 | 12, |
| 415 | "HMAC-SHA1-96" |
| 416 | }; |
| 417 | |
| 418 | const struct ssh_mac ssh_hmac_sha1_buggy = { |
| 419 | sha1_make_context, sha1_free_context, sha1_key_buggy, |
| 420 | sha1_generate, sha1_verify, |
| 421 | hmacsha1_start, hmacsha1_bytes, hmacsha1_genresult, hmacsha1_verresult, |
| 422 | "hmac-sha1", |
| 423 | 20, |
| 424 | "bug-compatible HMAC-SHA1" |
| 425 | }; |
| 426 | |
| 427 | const struct ssh_mac ssh_hmac_sha1_96_buggy = { |
| 428 | sha1_make_context, sha1_free_context, sha1_key_buggy, |
| 429 | sha1_96_generate, sha1_96_verify, |
| 430 | hmacsha1_start, hmacsha1_bytes, |
| 431 | hmacsha1_96_genresult, hmacsha1_96_verresult, |
| 432 | "hmac-sha1-96", |
| 433 | 12, |
| 434 | "bug-compatible HMAC-SHA1-96" |
| 435 | }; |