/* md5.c - Functions to compute MD5 message digest of files or memory blocks according to the definition of MD5 in RFC 1321 from April 1992. Copyright (C) 1995 Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /* Written by Ulrich Drepper . */ #ifdef HAVE_CONFIG_H # include #endif #include #if STDC_HEADERS # include # include #else # ifndef HAVE_MEMCPY # define memcpy(d, s, n) bcopy ((s), (d), (n)) # endif #endif #include "md5.h" #ifdef WORDS_BIGENDIAN # define SWAP(n) \ (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24)) #else # define SWAP(n) (n) #endif /* This array contains the bytes used to pad the buffer to the next 64-byte boundary. (RFC 1321, 3.1: Step 1) */ static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ }; /* Initialize structure containing state of computation. (RFC 1321, 3.3: Step 3) */ void md5_init_ctx (ctx) struct md5_ctx *ctx; { ctx->A = 0x67452301; ctx->B = 0xefcdab89; ctx->C = 0x98badcfe; ctx->D = 0x10325476; } /* Put result from CTX in first 16 bytes following RESBUF. The result must be in little endian byte order. */ void * md5_read_ctx (ctx, resbuf) const struct md5_ctx *ctx; void *resbuf; { ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A); ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B); ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C); ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D); return resbuf; } /* Compute MD5 message digest for bytes read from STREAM. The resulting message digest number will be written into the 16 bytes beginning at RESBLOCK. */ int md5_stream (stream, resblock) FILE *stream; void *resblock; { /* Important: BLOCKSIZE must be a multiple of 64. */ #define BLOCKSIZE 4096 struct md5_ctx ctx; md5_uint32 len[2]; char buffer[BLOCKSIZE + 72]; size_t pad, sum; /* Initialize the computation context. */ md5_init_ctx (&ctx); len[0] = 0; len[1] = 0; /* Iterate over full file contents. */ while (1) { /* We read the file in blocks of BLOCKSIZE bytes. One call of the computation function processes the whole buffer so that with the next round of the loop another block can be read. */ size_t n; sum = 0; /* Read block. Take care for partial reads. */ do { n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream); sum += n; } while (sum < BLOCKSIZE && n != 0); if (n == 0 && ferror (stream)) return 1; /* RFC 1321 specifies the possible length of the file up to 2^64 bits. Here we only compute the number of bytes. Do a double word increment. */ len[0] += sum; if (len[0] < sum) ++len[1]; /* If end of file is reached, end the loop. */ if (n == 0) break; /* Process buffer with BLOCKSIZE bytes. Note that BLOCKSIZE % 64 == 0 */ md5_process_block (buffer, BLOCKSIZE, &ctx); } /* We can copy 64 byte because the buffer is always big enough. FILLBUF contains the needed bits. */ memcpy (&buffer[sum], fillbuf, 64); /* Compute amount of padding bytes needed. Alignment is done to (N + PAD) % 64 == 56 There is always at least one byte padded. I.e. even the alignment is correctly aligned 64 padding bytes are added. */ pad = sum & 63; pad = pad >= 56 ? 64 + 56 - pad : 56 - pad; /* Put the 64-bit file length in *bits* at the end of the buffer. */ *(md5_uint32 *) &buffer[sum + pad] = SWAP (len[0] << 3); *(md5_uint32 *) &buffer[sum + pad + 4] = SWAP ((len[1] << 3) | (len[0] >> 29)); /* Process last bytes. */ md5_process_block (buffer, sum + pad + 8, &ctx); /* Construct result in desired memory. */ md5_read_ctx (&ctx, resblock); return 0; } /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The result is always in little endian byte order, so that a byte-wise output yields to the wanted ASCII representation of the message digest. */ void * md5_buffer (buffer, len, resblock) const char *buffer; size_t len; void *resblock; { struct md5_ctx ctx; char restbuf[64 + 72]; size_t blocks = len & ~63; size_t pad, rest; /* Initialize the computation context. */ md5_init_ctx (&ctx); /* Process whole buffer but last len % 64 bytes. */ md5_process_block (buffer, blocks, &ctx); /* REST bytes are not processed yet. */ rest = len - blocks; /* Copy to own buffer. */ memcpy (restbuf, &buffer[blocks], rest); /* Append needed fill bytes at end of buffer. We can copy 64 byte because the buffer is always big enough. */ memcpy (&restbuf[rest], fillbuf, 64); /* PAD bytes are used for padding to correct alignment. Note that always at least one byte is padded. */ pad = rest >= 56 ? 64 + 56 - rest : 56 - rest; /* Put length of buffer in *bits* in last eight bytes. */ *(md5_uint32 *) &restbuf[rest + pad] = (md5_uint32) SWAP (len << 3); *(md5_uint32 *) &restbuf[rest + pad + 4] = (md5_uint32) SWAP (len >> 29); /* Process last bytes. */ md5_process_block (restbuf, rest + pad + 8, &ctx); /* Put result in desired memory area. */ return md5_read_ctx (&ctx, resblock); } /* These are the four functions used in the four steps of the MD5 algorithm and defined in the RFC 1321. The first function is a little bit optimized (as found in Colin Plumbs public domain implementation). */ /* #define FF(b, c, d) ((b & c) | (~b & d)) */ #define FF(b, c, d) (d ^ (b & (c ^ d))) #define FG(b, c, d) FF (d, b, c) #define FH(b, c, d) (b ^ c ^ d) #define FI(b, c, d) (c ^ (b | ~d)) /* Process LEN bytes of BUFFER, accumulating context into CTX. It is assumed that LEN % 64 == 0. */ void md5_process_block (buffer, len, ctx) const void *buffer; size_t len; struct md5_ctx *ctx; { md5_uint32 correct_words[16]; const md5_uint32 *words = buffer; size_t nwords = len / sizeof (md5_uint32); const md5_uint32 *endp = words + nwords; md5_uint32 A = ctx->A; md5_uint32 B = ctx->B; md5_uint32 C = ctx->C; md5_uint32 D = ctx->D; /* Process all bytes in the buffer with 64 bytes in each round of the loop. */ while (words < endp) { md5_uint32 *cwp = correct_words; md5_uint32 A_save = A; md5_uint32 B_save = B; md5_uint32 C_save = C; md5_uint32 D_save = D; /* First round: using the given function, the context and a constant the next context is computed. Because the algorithms processing unit is a 32-bit word and it is determined to work on words in little endian byte order we perhaps have to change the byte order before the computation. To reduce the work for the next steps we store the swapped words in the array CORRECT_WORDS. */ #define OP(a, b, c, d, s, T) \ do \ { \ a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \ ++words; \ CYCLIC (a, s); \ a += b; \ } \ while (0) /* It is unfortunate that C does not provide an operator for cyclic rotation. Hope the C compiler is smart enough. */ #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s))) /* Before we start, one word to the strange constants. They are defined in RFC 1321 as T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64 */ /* Round 1. */ OP (A, B, C, D, 7, 0xd76aa478); OP (D, A, B, C, 12, 0xe8c7b756); OP (C, D, A, B, 17, 0x242070db); OP (B, C, D, A, 22, 0xc1bdceee); OP (A, B, C, D, 7, 0xf57c0faf); OP (D, A, B, C, 12, 0x4787c62a); OP (C, D, A, B, 17, 0xa8304613); OP (B, C, D, A, 22, 0xfd469501); OP (A, B, C, D, 7, 0x698098d8); OP (D, A, B, C, 12, 0x8b44f7af); OP (C, D, A, B, 17, 0xffff5bb1); OP (B, C, D, A, 22, 0x895cd7be); OP (A, B, C, D, 7, 0x6b901122); OP (D, A, B, C, 12, 0xfd987193); OP (C, D, A, B, 17, 0xa679438e); OP (B, C, D, A, 22, 0x49b40821); /* For the second to fourth round we have the possibly swapped words in CORRECT_WORDS. Redefine the macro to take an additional first argument specifying the function to use. */ #undef OP #define OP(f, a, b, c, d, k, s, T) \ do \ { \ a += f (b, c, d) + correct_words[k] + T; \ CYCLIC (a, s); \ a += b; \ } \ while (0) /* Round 2. */ OP (FG, A, B, C, D, 1, 5, 0xf61e2562); OP (FG, D, A, B, C, 6, 9, 0xc040b340); OP (FG, C, D, A, B, 11, 14, 0x265e5a51); OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa); OP (FG, A, B, C, D, 5, 5, 0xd62f105d); OP (FG, D, A, B, C, 10, 9, 0x02441453); OP (FG, C, D, A, B, 15, 14, 0xd8a1e681); OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8); OP (FG, A, B, C, D, 9, 5, 0x21e1cde6); OP (FG, D, A, B, C, 14, 9, 0xc33707d6); OP (FG, C, D, A, B, 3, 14, 0xf4d50d87); OP (FG, B, C, D, A, 8, 20, 0x455a14ed); OP (FG, A, B, C, D, 13, 5, 0xa9e3e905); OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8); OP (FG, C, D, A, B, 7, 14, 0x676f02d9); OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a); /* Round 3. */ OP (FH, A, B, C, D, 5, 4, 0xfffa3942); OP (FH, D, A, B, C, 8, 11, 0x8771f681); OP (FH, C, D, A, B, 11, 16, 0x6d9d6122); OP (FH, B, C, D, A, 14, 23, 0xfde5380c); OP (FH, A, B, C, D, 1, 4, 0xa4beea44); OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9); OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60); OP (FH, B, C, D, A, 10, 23, 0xbebfbc70); OP (FH, A, B, C, D, 13, 4, 0x289b7ec6); OP (FH, D, A, B, C, 0, 11, 0xeaa127fa); OP (FH, C, D, A, B, 3, 16, 0xd4ef3085); OP (FH, B, C, D, A, 6, 23, 0x04881d05); OP (FH, A, B, C, D, 9, 4, 0xd9d4d039); OP (FH, D, A, B, C, 12, 11, 0xe6db99e5); OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8); OP (FH, B, C, D, A, 2, 23, 0xc4ac5665); /* Round 4. */ OP (FI, A, B, C, D, 0, 6, 0xf4292244); OP (FI, D, A, B, C, 7, 10, 0x432aff97); OP (FI, C, D, A, B, 14, 15, 0xab9423a7); OP (FI, B, C, D, A, 5, 21, 0xfc93a039); OP (FI, A, B, C, D, 12, 6, 0x655b59c3); OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92); OP (FI, C, D, A, B, 10, 15, 0xffeff47d); OP (FI, B, C, D, A, 1, 21, 0x85845dd1); OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f); OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0); OP (FI, C, D, A, B, 6, 15, 0xa3014314); OP (FI, B, C, D, A, 13, 21, 0x4e0811a1); OP (FI, A, B, C, D, 4, 6, 0xf7537e82); OP (FI, D, A, B, C, 11, 10, 0xbd3af235); OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb); OP (FI, B, C, D, A, 9, 21, 0xeb86d391); /* Add the starting values of the context. */ A += A_save; B += B_save; C += C_save; D += D_save; } /* Put checksum in context given as argument. */ ctx->A = A; ctx->B = B; ctx->C = C; ctx->D = D; }