1/* vi: set sw=4 ts=4: */ 2/* 3 * md5.c - Compute MD5 checksum of strings according to the 4 * definition of MD5 in RFC 1321 from April 1992. 5 * 6 * Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. 7 * 8 * Copyright (C) 1995-1999 Free Software Foundation, Inc. 9 * Copyright (C) 2001 Manuel Novoa III 10 * Copyright (C) 2003 Glenn L. McGrath 11 * Copyright (C) 2003 Erik Andersen 12 * 13 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. 14 */ 15 16#include "libbb.h" 17 18#if CONFIG_MD5_SIZE_VS_SPEED < 0 || CONFIG_MD5_SIZE_VS_SPEED > 3 19# define MD5_SIZE_VS_SPEED 2 20#else 21# define MD5_SIZE_VS_SPEED CONFIG_MD5_SIZE_VS_SPEED 22#endif 23 24/* Initialize structure containing state of computation. 25 * (RFC 1321, 3.3: Step 3) 26 */ 27void md5_begin(md5_ctx_t *ctx) 28{ 29 ctx->A = 0x67452301; 30 ctx->B = 0xefcdab89; 31 ctx->C = 0x98badcfe; 32 ctx->D = 0x10325476; 33 34 ctx->total = 0; 35 ctx->buflen = 0; 36} 37 38/* These are the four functions used in the four steps of the MD5 algorithm 39 * and defined in the RFC 1321. The first function is a little bit optimized 40 * (as found in Colin Plumbs public domain implementation). 41 * #define FF(b, c, d) ((b & c) | (~b & d)) 42 */ 43# define FF(b, c, d) (d ^ (b & (c ^ d))) 44# define FG(b, c, d) FF (d, b, c) 45# define FH(b, c, d) (b ^ c ^ d) 46# define FI(b, c, d) (c ^ (b | ~d)) 47 48/* Hash a single block, 64 bytes long and 4-byte aligned. */ 49static void md5_hash_block(const void *buffer, md5_ctx_t *ctx) 50{ 51 uint32_t correct_words[16]; 52 const uint32_t *words = buffer; 53 54# if MD5_SIZE_VS_SPEED > 0 55 static const uint32_t C_array[] = { 56 /* round 1 */ 57 0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 58 0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501, 59 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be, 60 0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821, 61 /* round 2 */ 62 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, 63 0xd62f105d, 0x2441453, 0xd8a1e681, 0xe7d3fbc8, 64 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 65 0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a, 66 /* round 3 */ 67 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, 68 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70, 69 0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x4881d05, 70 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665, 71 /* round 4 */ 72 0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 73 0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1, 74 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1, 75 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391 76 }; 77 78 static const char P_array[] ALIGN1 = { 79# if MD5_SIZE_VS_SPEED > 1 80 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, /* 1 */ 81# endif /* MD5_SIZE_VS_SPEED > 1 */ 82 1, 6, 11, 0, 5, 10, 15, 4, 9, 14, 3, 8, 13, 2, 7, 12, /* 2 */ 83 5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2, /* 3 */ 84 0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9 /* 4 */ 85 }; 86 87# if MD5_SIZE_VS_SPEED > 1 88 static const char S_array[] ALIGN1 = { 89 7, 12, 17, 22, 90 5, 9, 14, 20, 91 4, 11, 16, 23, 92 6, 10, 15, 21 93 }; 94# endif /* MD5_SIZE_VS_SPEED > 1 */ 95# endif 96 97 uint32_t A = ctx->A; 98 uint32_t B = ctx->B; 99 uint32_t C = ctx->C; 100 uint32_t D = ctx->D; 101 102 /* Process all bytes in the buffer with 64 bytes in each round of 103 the loop. */ 104 uint32_t *cwp = correct_words; 105 uint32_t A_save = A; 106 uint32_t B_save = B; 107 uint32_t C_save = C; 108 uint32_t D_save = D; 109 110# if MD5_SIZE_VS_SPEED > 1 111# define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s))) 112 113 const uint32_t *pc; 114 const char *pp; 115 const char *ps; 116 int i; 117 uint32_t temp; 118 119 for (i = 0; i < 16; i++) { 120 cwp[i] = SWAP_LE32(words[i]); 121 } 122 words += 16; 123 124# if MD5_SIZE_VS_SPEED > 2 125 pc = C_array; 126 pp = P_array; 127 ps = S_array - 4; 128 129 for (i = 0; i < 64; i++) { 130 if ((i & 0x0f) == 0) 131 ps += 4; 132 temp = A; 133 switch (i >> 4) { 134 case 0: 135 temp += FF(B, C, D); 136 break; 137 case 1: 138 temp += FG(B, C, D); 139 break; 140 case 2: 141 temp += FH(B, C, D); 142 break; 143 case 3: 144 temp += FI(B, C, D); 145 } 146 temp += cwp[(int) (*pp++)] + *pc++; 147 CYCLIC(temp, ps[i & 3]); 148 temp += B; 149 A = D; 150 D = C; 151 C = B; 152 B = temp; 153 } 154# else 155 pc = C_array; 156 pp = P_array; 157 ps = S_array; 158 159 for (i = 0; i < 16; i++) { 160 temp = A + FF(B, C, D) + cwp[(int) (*pp++)] + *pc++; 161 CYCLIC(temp, ps[i & 3]); 162 temp += B; 163 A = D; 164 D = C; 165 C = B; 166 B = temp; 167 } 168 169 ps += 4; 170 for (i = 0; i < 16; i++) { 171 temp = A + FG(B, C, D) + cwp[(int) (*pp++)] + *pc++; 172 CYCLIC(temp, ps[i & 3]); 173 temp += B; 174 A = D; 175 D = C; 176 C = B; 177 B = temp; 178 } 179 ps += 4; 180 for (i = 0; i < 16; i++) { 181 temp = A + FH(B, C, D) + cwp[(int) (*pp++)] + *pc++; 182 CYCLIC(temp, ps[i & 3]); 183 temp += B; 184 A = D; 185 D = C; 186 C = B; 187 B = temp; 188 } 189 ps += 4; 190 for (i = 0; i < 16; i++) { 191 temp = A + FI(B, C, D) + cwp[(int) (*pp++)] + *pc++; 192 CYCLIC(temp, ps[i & 3]); 193 temp += B; 194 A = D; 195 D = C; 196 C = B; 197 B = temp; 198 } 199 200# endif /* MD5_SIZE_VS_SPEED > 2 */ 201# else 202 /* First round: using the given function, the context and a constant 203 the next context is computed. Because the algorithms processing 204 unit is a 32-bit word and it is determined to work on words in 205 little endian byte order we perhaps have to change the byte order 206 before the computation. To reduce the work for the next steps 207 we store the swapped words in the array CORRECT_WORDS. */ 208 209# define OP(a, b, c, d, s, T) \ 210 do \ 211 { \ 212 a += FF (b, c, d) + (*cwp++ = SWAP_LE32(*words)) + T; \ 213 ++words; \ 214 CYCLIC (a, s); \ 215 a += b; \ 216 } \ 217 while (0) 218 219 /* It is unfortunate that C does not provide an operator for 220 cyclic rotation. Hope the C compiler is smart enough. */ 221 /* gcc 2.95.4 seems to be --aaronl */ 222# define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s))) 223 224 /* Before we start, one word to the strange constants. 225 They are defined in RFC 1321 as 226 227 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64 228 */ 229 230# if MD5_SIZE_VS_SPEED == 1 231 const uint32_t *pc; 232 const char *pp; 233 int i; 234# endif /* MD5_SIZE_VS_SPEED */ 235 236 /* Round 1. */ 237# if MD5_SIZE_VS_SPEED == 1 238 pc = C_array; 239 for (i = 0; i < 4; i++) { 240 OP(A, B, C, D, 7, *pc++); 241 OP(D, A, B, C, 12, *pc++); 242 OP(C, D, A, B, 17, *pc++); 243 OP(B, C, D, A, 22, *pc++); 244 } 245# else 246 OP(A, B, C, D, 7, 0xd76aa478); 247 OP(D, A, B, C, 12, 0xe8c7b756); 248 OP(C, D, A, B, 17, 0x242070db); 249 OP(B, C, D, A, 22, 0xc1bdceee); 250 OP(A, B, C, D, 7, 0xf57c0faf); 251 OP(D, A, B, C, 12, 0x4787c62a); 252 OP(C, D, A, B, 17, 0xa8304613); 253 OP(B, C, D, A, 22, 0xfd469501); 254 OP(A, B, C, D, 7, 0x698098d8); 255 OP(D, A, B, C, 12, 0x8b44f7af); 256 OP(C, D, A, B, 17, 0xffff5bb1); 257 OP(B, C, D, A, 22, 0x895cd7be); 258 OP(A, B, C, D, 7, 0x6b901122); 259 OP(D, A, B, C, 12, 0xfd987193); 260 OP(C, D, A, B, 17, 0xa679438e); 261 OP(B, C, D, A, 22, 0x49b40821); 262# endif /* MD5_SIZE_VS_SPEED == 1 */ 263 264 /* For the second to fourth round we have the possibly swapped words 265 in CORRECT_WORDS. Redefine the macro to take an additional first 266 argument specifying the function to use. */ 267# undef OP 268# define OP(f, a, b, c, d, k, s, T) \ 269 do \ 270 { \ 271 a += f (b, c, d) + correct_words[k] + T; \ 272 CYCLIC (a, s); \ 273 a += b; \ 274 } \ 275 while (0) 276 277 /* Round 2. */ 278# if MD5_SIZE_VS_SPEED == 1 279 pp = P_array; 280 for (i = 0; i < 4; i++) { 281 OP(FG, A, B, C, D, (int) (*pp++), 5, *pc++); 282 OP(FG, D, A, B, C, (int) (*pp++), 9, *pc++); 283 OP(FG, C, D, A, B, (int) (*pp++), 14, *pc++); 284 OP(FG, B, C, D, A, (int) (*pp++), 20, *pc++); 285 } 286# else 287 OP(FG, A, B, C, D, 1, 5, 0xf61e2562); 288 OP(FG, D, A, B, C, 6, 9, 0xc040b340); 289 OP(FG, C, D, A, B, 11, 14, 0x265e5a51); 290 OP(FG, B, C, D, A, 0, 20, 0xe9b6c7aa); 291 OP(FG, A, B, C, D, 5, 5, 0xd62f105d); 292 OP(FG, D, A, B, C, 10, 9, 0x02441453); 293 OP(FG, C, D, A, B, 15, 14, 0xd8a1e681); 294 OP(FG, B, C, D, A, 4, 20, 0xe7d3fbc8); 295 OP(FG, A, B, C, D, 9, 5, 0x21e1cde6); 296 OP(FG, D, A, B, C, 14, 9, 0xc33707d6); 297 OP(FG, C, D, A, B, 3, 14, 0xf4d50d87); 298 OP(FG, B, C, D, A, 8, 20, 0x455a14ed); 299 OP(FG, A, B, C, D, 13, 5, 0xa9e3e905); 300 OP(FG, D, A, B, C, 2, 9, 0xfcefa3f8); 301 OP(FG, C, D, A, B, 7, 14, 0x676f02d9); 302 OP(FG, B, C, D, A, 12, 20, 0x8d2a4c8a); 303# endif /* MD5_SIZE_VS_SPEED == 1 */ 304 305 /* Round 3. */ 306# if MD5_SIZE_VS_SPEED == 1 307 for (i = 0; i < 4; i++) { 308 OP(FH, A, B, C, D, (int) (*pp++), 4, *pc++); 309 OP(FH, D, A, B, C, (int) (*pp++), 11, *pc++); 310 OP(FH, C, D, A, B, (int) (*pp++), 16, *pc++); 311 OP(FH, B, C, D, A, (int) (*pp++), 23, *pc++); 312 } 313# else 314 OP(FH, A, B, C, D, 5, 4, 0xfffa3942); 315 OP(FH, D, A, B, C, 8, 11, 0x8771f681); 316 OP(FH, C, D, A, B, 11, 16, 0x6d9d6122); 317 OP(FH, B, C, D, A, 14, 23, 0xfde5380c); 318 OP(FH, A, B, C, D, 1, 4, 0xa4beea44); 319 OP(FH, D, A, B, C, 4, 11, 0x4bdecfa9); 320 OP(FH, C, D, A, B, 7, 16, 0xf6bb4b60); 321 OP(FH, B, C, D, A, 10, 23, 0xbebfbc70); 322 OP(FH, A, B, C, D, 13, 4, 0x289b7ec6); 323 OP(FH, D, A, B, C, 0, 11, 0xeaa127fa); 324 OP(FH, C, D, A, B, 3, 16, 0xd4ef3085); 325 OP(FH, B, C, D, A, 6, 23, 0x04881d05); 326 OP(FH, A, B, C, D, 9, 4, 0xd9d4d039); 327 OP(FH, D, A, B, C, 12, 11, 0xe6db99e5); 328 OP(FH, C, D, A, B, 15, 16, 0x1fa27cf8); 329 OP(FH, B, C, D, A, 2, 23, 0xc4ac5665); 330# endif /* MD5_SIZE_VS_SPEED == 1 */ 331 332 /* Round 4. */ 333# if MD5_SIZE_VS_SPEED == 1 334 for (i = 0; i < 4; i++) { 335 OP(FI, A, B, C, D, (int) (*pp++), 6, *pc++); 336 OP(FI, D, A, B, C, (int) (*pp++), 10, *pc++); 337 OP(FI, C, D, A, B, (int) (*pp++), 15, *pc++); 338 OP(FI, B, C, D, A, (int) (*pp++), 21, *pc++); 339 } 340# else 341 OP(FI, A, B, C, D, 0, 6, 0xf4292244); 342 OP(FI, D, A, B, C, 7, 10, 0x432aff97); 343 OP(FI, C, D, A, B, 14, 15, 0xab9423a7); 344 OP(FI, B, C, D, A, 5, 21, 0xfc93a039); 345 OP(FI, A, B, C, D, 12, 6, 0x655b59c3); 346 OP(FI, D, A, B, C, 3, 10, 0x8f0ccc92); 347 OP(FI, C, D, A, B, 10, 15, 0xffeff47d); 348 OP(FI, B, C, D, A, 1, 21, 0x85845dd1); 349 OP(FI, A, B, C, D, 8, 6, 0x6fa87e4f); 350 OP(FI, D, A, B, C, 15, 10, 0xfe2ce6e0); 351 OP(FI, C, D, A, B, 6, 15, 0xa3014314); 352 OP(FI, B, C, D, A, 13, 21, 0x4e0811a1); 353 OP(FI, A, B, C, D, 4, 6, 0xf7537e82); 354 OP(FI, D, A, B, C, 11, 10, 0xbd3af235); 355 OP(FI, C, D, A, B, 2, 15, 0x2ad7d2bb); 356 OP(FI, B, C, D, A, 9, 21, 0xeb86d391); 357# endif /* MD5_SIZE_VS_SPEED == 1 */ 358# endif /* MD5_SIZE_VS_SPEED > 1 */ 359 360 /* Add the starting values of the context. */ 361 A += A_save; 362 B += B_save; 363 C += C_save; 364 D += D_save; 365 366 /* Put checksum in context given as argument. */ 367 ctx->A = A; 368 ctx->B = B; 369 ctx->C = C; 370 ctx->D = D; 371} 372 373/* Feed data through a temporary buffer to call md5_hash_aligned_block() 374 * with chunks of data that are 4-byte aligned and a multiple of 64 bytes. 375 * This function's internal buffer remembers previous data until it has 64 376 * bytes worth to pass on. Call md5_end() to flush this buffer. */ 377 378void md5_hash(const void *buffer, size_t len, md5_ctx_t *ctx) 379{ 380 char *buf=(char *)buffer; 381 382 /* RFC 1321 specifies the possible length of the file up to 2^64 bits, 383 * Here we only track the number of bytes. */ 384 385 ctx->total += len; 386 387 // Process all input. 388 389 while (len) { 390 int i = 64 - ctx->buflen; 391 392 // Copy data into aligned buffer. 393 394 if (i > len) i = len; 395 memcpy(ctx->buffer + ctx->buflen, buf, i); 396 len -= i; 397 ctx->buflen += i; 398 buf += i; 399 400 // When buffer fills up, process it. 401 402 if (ctx->buflen == 64) { 403 md5_hash_block(ctx->buffer, ctx); 404 ctx->buflen = 0; 405 } 406 } 407} 408 409/* Process the remaining bytes in the buffer and put result from CTX 410 * in first 16 bytes following RESBUF. The result is always in little 411 * endian byte order, so that a byte-wise output yields to the wanted 412 * ASCII representation of the message digest. 413 * 414 * IMPORTANT: On some systems it is required that RESBUF is correctly 415 * aligned for a 32 bits value. 416 */ 417void *md5_end(void *resbuf, md5_ctx_t *ctx) 418{ 419 char *buf = ctx->buffer; 420 int i; 421 422 /* Pad data to block size. */ 423 424 buf[ctx->buflen++] = 0x80; 425 memset(buf + ctx->buflen, 0, 128 - ctx->buflen); 426 427 /* Put the 64-bit file length in *bits* at the end of the buffer. */ 428 ctx->total <<= 3; 429 if (ctx->buflen > 56) buf += 64; 430 for (i = 0; i < 8; i++) buf[56 + i] = ctx->total >> (i*8); 431 432 /* Process last bytes. */ 433 if (buf != ctx->buffer) md5_hash_block(ctx->buffer, ctx); 434 md5_hash_block(buf, ctx); 435 436 /* Put result from CTX in first 16 bytes following RESBUF. The result is 437 * always in little endian byte order, so that a byte-wise output yields 438 * to the wanted ASCII representation of the message digest. 439 * 440 * IMPORTANT: On some systems it is required that RESBUF is correctly 441 * aligned for a 32 bits value. 442 */ 443 ((uint32_t *) resbuf)[0] = SWAP_LE32(ctx->A); 444 ((uint32_t *) resbuf)[1] = SWAP_LE32(ctx->B); 445 ((uint32_t *) resbuf)[2] = SWAP_LE32(ctx->C); 446 ((uint32_t *) resbuf)[3] = SWAP_LE32(ctx->D); 447 448 return resbuf; 449} 450