426 lines
12 KiB
C
426 lines
12 KiB
C
/* mcookie.c -- Generates random numbers for xauth
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* Created: Fri Feb 3 10:42:48 1995 by faith@cs.unc.edu
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* Revised: Fri Mar 19 07:48:01 1999 by faith@acm.org
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* Public Domain 1995, 1999 Rickard E. Faith (faith@acm.org)
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* This program comes with ABSOLUTELY NO WARRANTY.
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*
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* $Id: mcookie.c,v 1.5 1997/07/06 00:13:06 aebr Exp $
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*
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* This program gathers some random bits of data and used the MD5
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* message-digest algorithm to generate a 128-bit hexadecimal number for
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* use with xauth(1).
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*
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* NOTE: Unless /dev/random is available, this program does not actually
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* gather 128 bits of random information, so the magic cookie generated
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* will be considerably easier to guess than one might expect.
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*
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* 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@pld.ORG.PL>
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* - added Native Language Support
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* 1999-03-21 aeb: Added some fragments of code from Colin Plumb.
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <sys/time.h>
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#include <time.h>
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#include <unistd.h>
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#define BUFFERSIZE 4096
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#ifndef MD5_H
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#define MD5_H
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#if defined (__alpha__) || defined (__ia64__) || defined (__x86_64__)
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typedef unsigned int uint32;
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#else
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typedef unsigned long uint32;
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#endif
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struct MD5Context {
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uint32 buf[4];
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uint32 bits[2];
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unsigned char in[64];
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};
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void MD5Init(struct MD5Context *context);
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void MD5Update(struct MD5Context *context, unsigned char const *buf,
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unsigned len);
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void MD5Final(unsigned char digest[16], struct MD5Context *context);
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void MD5Transform(uint32 buf[4], uint32 const in[16]);
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/*
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* This is needed to make RSAREF happy on some MS-DOS compilers.
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*/
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typedef struct MD5Context MD5_CTX;
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#endif /* !MD5_H */
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/*
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* This code implements the MD5 message-digest algorithm.
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* The algorithm is due to Ron Rivest. This code was
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* written by Colin Plumb in 1993, no copyright is claimed.
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* This code is in the public domain; do with it what you wish.
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*
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* Equivalent code is available from RSA Data Security, Inc.
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* This code has been tested against that, and is equivalent,
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* except that you don't need to include two pages of legalese
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* with every copy.
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*
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* To compute the message digest of a chunk of bytes, declare an
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* MD5Context structure, pass it to MD5Init, call MD5Update as
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* needed on buffers full of bytes, and then call MD5Final, which
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* will fill a supplied 16-byte array with the digest.
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*/
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#include <string.h> /* for memcpy() */
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#include <endian.h>
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#if __BYTE_ORDER == __LITTLE_ENDIAN
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#define byteReverse(buf, len) /* Nothing */
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#else
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void byteReverse(unsigned char *buf, unsigned longs);
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/*
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* Note: this code is harmless on little-endian machines.
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*/
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void byteReverse(unsigned char *buf, unsigned longs)
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{
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uint32 t;
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do {
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t = (uint32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
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((unsigned) buf[1] << 8 | buf[0]);
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*(uint32 *) buf = t;
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buf += 4;
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} while (--longs);
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}
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#endif
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/*
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* Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
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* initialization constants.
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*/
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void MD5Init(struct MD5Context *ctx)
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{
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ctx->buf[0] = 0x67452301;
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ctx->buf[1] = 0xefcdab89;
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ctx->buf[2] = 0x98badcfe;
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ctx->buf[3] = 0x10325476;
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ctx->bits[0] = 0;
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ctx->bits[1] = 0;
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}
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/*
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* Update context to reflect the concatenation of another buffer full
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* of bytes.
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*/
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void MD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len)
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{
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uint32 t;
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/* Update bitcount */
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t = ctx->bits[0];
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if ((ctx->bits[0] = t + ((uint32) len << 3)) < t)
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ctx->bits[1]++; /* Carry from low to high */
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ctx->bits[1] += len >> 29;
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t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */
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/* Handle any leading odd-sized chunks */
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if (t) {
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unsigned char *p = (unsigned char *) ctx->in + t;
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t = 64 - t;
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if (len < t) {
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memcpy(p, buf, len);
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return;
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}
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memcpy(p, buf, t);
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byteReverse(ctx->in, 16);
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MD5Transform(ctx->buf, (uint32 *) ctx->in);
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buf += t;
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len -= t;
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}
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/* Process data in 64-byte chunks */
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while (len >= 64) {
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memcpy(ctx->in, buf, 64);
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byteReverse(ctx->in, 16);
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MD5Transform(ctx->buf, (uint32 *) ctx->in);
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buf += 64;
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len -= 64;
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}
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/* Handle any remaining bytes of data. */
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memcpy(ctx->in, buf, len);
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}
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/*
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* Final wrapup - pad to 64-byte boundary with the bit pattern
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* 1 0* (64-bit count of bits processed, MSB-first)
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*/
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void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
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{
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unsigned count;
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unsigned char *p;
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/* Compute number of bytes mod 64 */
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count = (ctx->bits[0] >> 3) & 0x3F;
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/* Set the first char of padding to 0x80. This is safe since there is
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always at least one byte free */
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p = ctx->in + count;
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*p++ = 0x80;
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/* Bytes of padding needed to make 64 bytes */
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count = 64 - 1 - count;
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/* Pad out to 56 mod 64 */
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if (count < 8) {
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/* Two lots of padding: Pad the first block to 64 bytes */
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memset(p, 0, count);
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byteReverse(ctx->in, 16);
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MD5Transform(ctx->buf, (uint32 *) ctx->in);
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/* Now fill the next block with 56 bytes */
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memset(ctx->in, 0, 56);
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} else {
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/* Pad block to 56 bytes */
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memset(p, 0, count - 8);
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}
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byteReverse(ctx->in, 14);
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/* Append length in bits and transform */
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((uint32 *) ctx->in)[14] = ctx->bits[0];
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((uint32 *) ctx->in)[15] = ctx->bits[1];
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MD5Transform(ctx->buf, (uint32 *) ctx->in);
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byteReverse((unsigned char *) ctx->buf, 4);
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memcpy(digest, ctx->buf, 16);
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memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */
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}
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/* The four core functions - F1 is optimized somewhat */
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/* #define F1(x, y, z) (x & y | ~x & z) */
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#define F1(x, y, z) (z ^ (x & (y ^ z)))
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#define F2(x, y, z) F1(z, x, y)
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#define F3(x, y, z) (x ^ y ^ z)
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#define F4(x, y, z) (y ^ (x | ~z))
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/* This is the central step in the MD5 algorithm. */
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#define MD5STEP(f, w, x, y, z, data, s) \
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( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )
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/*
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* The core of the MD5 algorithm, this alters an existing MD5 hash to
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* reflect the addition of 16 longwords of new data. MD5Update blocks
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* the data and converts bytes into longwords for this routine.
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*/
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void MD5Transform(uint32 buf[4], uint32 const in[16])
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{
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register uint32 a, b, c, d;
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a = buf[0];
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b = buf[1];
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c = buf[2];
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d = buf[3];
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MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
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MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
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MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
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MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
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MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
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MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
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MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
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MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
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MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
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MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
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MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
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MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
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MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
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MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
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MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
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MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
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MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
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MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
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MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
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MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
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MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
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MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
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MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
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MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
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MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
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MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
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MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
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MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
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MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
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MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
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MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
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MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
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MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
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MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
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MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
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MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
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MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
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MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
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MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
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MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
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MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
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MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
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MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
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MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
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MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
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MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
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MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
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MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
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MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
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MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
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MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
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MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
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MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
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MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
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MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
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MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
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MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
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MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
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MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
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MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
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MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
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MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
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MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
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MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
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buf[0] += a;
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buf[1] += b;
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buf[2] += c;
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buf[3] += d;
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}
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struct rngs {
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const char *path;
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int minlength, maxlength;
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} rngs[] = {
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{ "/dev/random", 16, 16 }, /* 16 bytes = 128 bits suffice */
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{ "/proc/interrupts", 0, 0 },
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{ "/proc/slabinfo", 0, 0 },
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{ "/proc/stat", 0, 0 },
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{ "/dev/urandom", 32, 64 },
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};
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#define RNGS (sizeof(rngs)/sizeof(struct rngs))
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int Verbose = 0;
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/* The basic function to hash a file */
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static off_t
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hash_file(struct MD5Context *ctx, int fd)
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{
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off_t count = 0;
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ssize_t r;
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unsigned char buf[BUFFERSIZE];
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while ((r = read(fd, buf, sizeof(buf))) > 0) {
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MD5Update(ctx, buf, r);
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count += r;
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}
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/* Separate files with a null byte */
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buf[0] = 0;
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MD5Update(ctx, buf, 1);
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return count;
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}
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int main( int argc, char **argv )
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{
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int i;
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struct MD5Context ctx;
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unsigned char digest[16];
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unsigned char buf[BUFFERSIZE];
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int fd;
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int c;
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pid_t pid;
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char *file = NULL;
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int r;
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struct timeval tv;
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struct timezone tz;
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while ((c = getopt( argc, argv, "vf:" )) != -1)
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switch (c) {
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case 'v': ++Verbose; break;
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case 'f': file = optarg; break;
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}
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MD5Init( &ctx );
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gettimeofday( &tv, &tz );
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MD5Update( &ctx, (unsigned char *)&tv, sizeof( tv ) );
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pid = getppid();
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MD5Update( &ctx, (unsigned char *)&pid, sizeof( pid ));
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pid = getpid();
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MD5Update( &ctx, (unsigned char *)&pid, sizeof( pid ));
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if (file) {
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int count = 0;
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if (file[0] == '-' && !file[1])
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fd = fileno(stdin);
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else
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fd = open( file, O_RDONLY );
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if (fd < 0) {
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fprintf( stderr, "Could not open %s\n", file );
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} else {
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count = hash_file( &ctx, fd );
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if (Verbose)
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fprintf( stderr, "Got %d bytes from %s\n", count, file );
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if (file[0] != '-' || file[1]) close( fd );
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}
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}
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for (i = 0; i < RNGS; i++) {
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if ((fd = open( rngs[i].path, O_RDONLY|O_NONBLOCK )) >= 0) {
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int count = sizeof(buf);
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if (rngs[i].maxlength && count > rngs[i].maxlength)
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count = rngs[i].maxlength;
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r = read( fd, buf, count );
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if (r > 0)
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MD5Update( &ctx, buf, r );
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else
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r = 0;
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close( fd );
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if (Verbose)
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fprintf( stderr, "Got %d bytes from %s\n", r, rngs[i].path );
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if (rngs[i].minlength && r >= rngs[i].minlength)
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break;
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} else if (Verbose)
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fprintf( stderr, "Could not open %s\n", rngs[i].path );
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}
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MD5Final( digest, &ctx );
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for (i = 0; i < 16; i++) printf( "%02x", digest[i] );
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putchar ( '\n' );
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/*
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* The following is important for cases like disk full, so shell scripts
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* can bomb out properly rather than think they succeeded.
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*/
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if (fflush(stdout) < 0 || fclose(stdout) < 0)
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return 1;
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return 0;
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}
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