/* 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, 1996 Free Software Foundation, Inc.
* NOTE: The canonical source of this file is maintained with the GNU C
* Library. Bugs can be reported to bug-glibc@prep.ai.mit.edu.
*
* 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 <drepper@gnu.ai.mit.edu>, 1995. */
#include "config.h"
#include <sys/types.h>
#if STDC_HEADERS || defined _LIBC
# include <stdlib.h>
# include <string.h>
#else
# ifndef HAVE_MEMCPY
# define memcpy(d, s, n) bcopy ((s), (d), (n))
# endif
#endif
#include "md5.h"
#ifdef _LIBC
# include <endian.h>
# if __BYTE_ORDER == __BIG_ENDIAN
# define WORDS_BIGENDIAN 1
# endif
#endif
#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;
ctx->total[0] = ctx->total[1] = 0;
ctx->buflen = 0;
}
/* Put result from CTX in first 16 bytes following RESBUF. The result
* must be in little endian byte order.
*
* IMPORTANT: On some systems it is required that RESBUF is correctly
* aligned for a 32 bits value. */
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;
}
/* Process the remaining bytes in the internal buffer and the usual
* prolog according to the standard and write the result to RESBUF.
*
* IMPORTANT: On some systems it is required that RESBUF is correctly
* aligned for a 32 bits value. */
void *md5_finish_ctx(ctx, resbuf)
struct md5_ctx *ctx;
void *resbuf;
{
/* Take yet unprocessed bytes into account. */
md5_uint32 bytes = ctx->buflen;
size_t pad;
/* Now count remaining bytes. */
ctx->total[0] += bytes;
if (ctx->total[0] < bytes)
++ctx->total[1];
pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
memcpy(&ctx->buffer[bytes], fillbuf, pad);
/* Put the 64-bit file length in *bits* at the end of the buffer. */
*(md5_uint32 *) & ctx->buffer[bytes + pad] = SWAP(ctx->total[0] << 3);
*(md5_uint32 *) & ctx->buffer[bytes + pad + 4] = SWAP((ctx->total[1] << 3) |
(ctx->total[0] >> 29));
/* Process last bytes. */
md5_process_block(ctx->buffer, bytes + pad + 8, ctx);
return md5_read_ctx(ctx, 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;
char buffer[BLOCKSIZE + 72];
size_t sum;
/* Initialize the computation context. */
md5_init_ctx(&ctx);
/* 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;
/* 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);
}
/* Add the last bytes if necessary. */
if (sum > 0)
md5_process_bytes(buffer, sum, &ctx);
/* Construct result in desired memory. */
md5_finish_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;
/* Initialize the computation context. */
md5_init_ctx(&ctx);
/* Process whole buffer but last len % 64 bytes. */
md5_process_bytes(buffer, len, &ctx);
/* Put result in desired memory area. */
return md5_finish_ctx(&ctx, resblock);
}
void md5_process_bytes(buffer, len, ctx)
const void *buffer;
size_t len;
struct md5_ctx *ctx;
{
/* When we already have some bits in our internal buffer concatenate
* both inputs first. */
if (ctx->buflen != 0) {
size_t left_over = ctx->buflen;
size_t add = 128 - left_over > len ? len : 128 - left_over;
memcpy(&ctx->buffer[left_over], buffer, add);
ctx->buflen += add;
if (left_over + add > 64) {
md5_process_block(ctx->buffer, (left_over + add) & ~63, ctx);
/* The regions in the following copy operation cannot overlap. */
memcpy(ctx->buffer, &ctx->buffer[(left_over + add) & ~63], (left_over + add) & 63);
ctx->buflen = (left_over + add) & 63;
}
buffer = (const char *) buffer + add;
len -= add;
}
/* Process available complete blocks. */
if (len > 64) {
md5_process_block(buffer, len & ~63, ctx);
buffer = (const char *) buffer + (len & ~63);
len &= 63;
}
/* Move remaining bytes in internal buffer. */
if (len > 0) {
memcpy(ctx->buffer, buffer, len);
ctx->buflen = len;
}
}
/* 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;
/* First increment the byte count. 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. */
ctx->total[0] += len;
if (ctx->total[0] < len)
++ctx->total[1];
/* 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;
}
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