simple MD5 checksum tool

Makefile

SRCS = md5.c md5cmp.c md5hl.c

OBJS = $(SRCS:%.c=%.o)

LD := g++
CC := gcc
STRIP := strip


all: md5

clean:
	rm -f md5 $(OBJS)

md5: $(OBJS)
	$(LD) $(LDFLAGS) -o $@ $^
	$(STRIP) $@

%.o: %.c
	$(CC) -c -O3 -Wall -Wextra $(CFLAGS) $(CPPFLAGS) -o $@ $<

md5.c

/*
 * MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm
 *
 * Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
 * rights reserved.
 *
 * License to copy and use this software is granted provided that it
 * is identified as the "RSA Data Security, Inc. MD5 Message-Digest
 * Algorithm" in all material mentioning or referencing this software
 * or this function.
 *
 * License is also granted to make and use derivative works provided
 * that such works are identified as "derived from the RSA Data
 * Security, Inc. MD5 Message-Digest Algorithm" in all material
 * mentioning or referencing the derived work.
 *
 * RSA Data Security, Inc. makes no representations concerning either
 * the merchantability of this software or the suitability of this
 * software for any particular purpose. It is provided "as is"
 * without express or implied warranty of any kind.
 *
 * These notices must be retained in any copies of any part of this
 * documentation and/or software.
 *
 * This code is the same as the code published by RSA Inc.  It has been
 * edited for clarity and style only.
 */

#include <sys/types.h>
#include <string.h>

#include "./md5.h"

static void MD5Transform(unsigned int [4], const unsigned char [64]);

#if (BYTE_ORDER == LITTLE_ENDIAN)
#define Encode memcpy
#define Decode memcpy
#else 

/*
 * Encodes input (unsigned int) into output (unsigned char). Assumes len is
 * a multiple of 4.
 */

static void
Encode (unsigned char *output, unsigned int *input, unsigned int len)
{
	unsigned int i;
	unsigned int *op = (unsigned int *)output;

	for (i = 0; i < len / 4; i++)
		op[i] = htole32(input[i]);
}

/*
 * Decodes input (unsigned char) into output (unsigned int). Assumes len is
 * a multiple of 4.
 */

static void
Decode (unsigned int *output, const unsigned char *input, unsigned int len)
{
	unsigned int i;
	const unsigned int *ip = (const unsigned int *)input;

	for (i = 0; i < len / 4; i++)
		output[i] = le32toh(ip[i]);
}
#endif

static unsigned char PADDING[64] = {
  0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

/* F, G, H and I are basic MD5 functions. */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits. */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/*
 * FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
 * Rotation is separate from addition to prevent recomputation.
 */
#define FF(a, b, c, d, x, s, ac) { \
	(a) += F ((b), (c), (d)) + (x) + (unsigned int)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define GG(a, b, c, d, x, s, ac) { \
	(a) += G ((b), (c), (d)) + (x) + (unsigned int)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define HH(a, b, c, d, x, s, ac) { \
	(a) += H ((b), (c), (d)) + (x) + (unsigned int)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define II(a, b, c, d, x, s, ac) { \
	(a) += I ((b), (c), (d)) + (x) + (unsigned int)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}

/* MD5 initialization. Begins an MD5 operation, writing a new context. */

void
MD5Init (context)
	MD5_CTX *context;
{

	context->count[0] = context->count[1] = 0;

	/* Load magic initialization constants.  */
	context->state[0] = 0x67452301;
	context->state[1] = 0xefcdab89;
	context->state[2] = 0x98badcfe;
	context->state[3] = 0x10325476;
}

/* 
 * MD5 block update operation. Continues an MD5 message-digest
 * operation, processing another message block, and updating the
 * context.
 */

void
MD5Update (context, in, inputLen)
	MD5_CTX *context;
	const void *in;
	unsigned int inputLen;
{
	unsigned int i, idx, partLen;
	const unsigned char *input = in;

	/* Compute number of bytes mod 64 */
	idx = (unsigned int)((context->count[0] >> 3) & 0x3F);

	/* Update number of bits */
	if ((context->count[0] += ((unsigned int)inputLen << 3))
	    < ((unsigned int)inputLen << 3))
		context->count[1]++;
	context->count[1] += ((unsigned int)inputLen >> 29);

	partLen = 64 - idx;

	/* Transform as many times as possible. */
	if (inputLen >= partLen) {
		memcpy((void *)&context->buffer[idx], (const void *)input,
		    partLen);
		MD5Transform (context->state, context->buffer);

		for (i = partLen; i + 63 < inputLen; i += 64)
			MD5Transform (context->state, &input[i]);

		idx = 0;
	}
	else
		i = 0;

	/* Buffer remaining input */
	memcpy ((void *)&context->buffer[idx], (const void *)&input[i],
	    inputLen-i);
}

/*
 * MD5 padding. Adds padding followed by original length.
 */

void
MD5Pad (context)
	MD5_CTX *context;
{
	unsigned char bits[8];
	unsigned int idx, padLen;

	/* Save number of bits */
	Encode (bits, context->count, 8);

	/* Pad out to 56 mod 64. */
	idx = (unsigned int)((context->count[0] >> 3) & 0x3f);
	padLen = (idx < 56) ? (56 - idx) : (120 - idx);
	MD5Update (context, PADDING, padLen);

	/* Append length (before padding) */
	MD5Update (context, bits, 8);
}

/*
 * MD5 finalization. Ends an MD5 message-digest operation, writing the
 * the message digest and zeroizing the context.
 */

void
MD5Final (digest, context)
	unsigned char digest[16];
	MD5_CTX *context;
{
	/* Do padding. */
	MD5Pad (context);

	/* Store state in digest */
	Encode (digest, context->state, 16);

	/* Zeroize sensitive information. */
	memset ((void *)context, 0, sizeof (*context));
}

/* MD5 basic transformation. Transforms state based on block. */

static void
MD5Transform (state, block)
	unsigned int state[4];
	const unsigned char block[64];
{
	unsigned int a = state[0], b = state[1], c = state[2], d = state[3], x[16];

	Decode (x, block, 64);

	/* Round 1 */
#define S11 7
#define S12 12
#define S13 17
#define S14 22
	FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
	FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
	FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
	FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
	FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
	FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
	FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
	FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
	FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
	FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
	FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
	FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
	FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
	FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
	FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
	FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

	/* Round 2 */
#define S21 5
#define S22 9
#define S23 14
#define S24 20
	GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
	GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
	GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
	GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
	GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
	GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
	GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
	GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
	GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
	GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
	GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
	GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
	GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
	GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
	GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
	GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

	/* Round 3 */
#define S31 4
#define S32 11
#define S33 16
#define S34 23
	HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
	HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
	HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
	HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
	HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
	HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
	HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
	HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
	HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
	HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
	HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
	HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
	HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
	HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
	HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
	HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

	/* Round 4 */
#define S41 6
#define S42 10
#define S43 15
#define S44 21
	II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
	II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
	II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
	II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
	II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
	II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
	II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
	II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
	II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
	II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
	II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
	II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
	II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
	II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
	II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
	II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;

	/* Zeroize sensitive information. */
	memset ((void *)x, 0, sizeof (x));
}

md5.h

/* MD5.H - header file for MD5C.C
 * $FreeBSD$
 */

/*-
 Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
rights reserved.

License to copy and use this software is granted provided that it
is identified as the "RSA Data Security, Inc. MD5 Message-Digest
Algorithm" in all material mentioning or referencing this software
or this function.

License is also granted to make and use derivative works provided
that such works are identified as "derived from the RSA Data
Security, Inc. MD5 Message-Digest Algorithm" in all material
mentioning or referencing the derived work.

RSA Data Security, Inc. makes no representations concerning either
the merchantability of this software or the suitability of this
software for any particular purpose. It is provided "as is"
without express or implied warranty of any kind.

These notices must be retained in any copies of any part of this
documentation and/or software.
 */

#ifndef _SYS_MD5_H_
#define _SYS_MD5_H_

#define MD5_BLOCK_LENGTH		64
#define MD5_DIGEST_LENGTH		16
#define MD5_DIGEST_STRING_LENGTH	(MD5_DIGEST_LENGTH * 2 + 1)

/* MD5 context. */
typedef struct MD5Context {
  unsigned int state[4];	/* state (ABCD) */
  unsigned int count[2];	/* number of bits, modulo 2^64 (lsb first) */
  unsigned char buffer[64];	/* input buffer */
} MD5_CTX;

void   MD5Init (MD5_CTX *);
void   MD5Update (MD5_CTX *, const void *, unsigned int);
void   MD5Final (unsigned char [16], MD5_CTX *);
char * MD5End(MD5_CTX *, char *);
char * MD5File(const char *, char *);
char * MD5FileChunk(const char *, char *, off_t, off_t);
char * MD5Data(const void *, unsigned int, char *);
#endif /* _SYS_MD5_H_ */

md5cmp.c

/*
 * Copyright (C)2013 D. R. Commander.  All Rights Reserved.
 *              2015 djcj <[email protected]>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * - Neither the name of the libjpeg-turbo Project nor the names of its
 *   contributors may be used to endorse or promote products derived from this
 *   software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS",
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include "./md5.h"

#define USAGE  fprintf(stderr, "USAGE: %s <file>\n", argv[0])
#define USAGE_COMPARE  fprintf(stderr, "USAGE: %s -c <correct MD5 sum> <file>\n", argv[0])

#define CHECK_FOR_MD5SUM(md5hash) \
md5sum = MD5File(md5hash, buf); \
if (!md5sum) { \
	perror("Could not obtain MD5 sum"); \
	return -1; \
}

int main(int argc, char *argv[])
{
	char *md5sum = NULL, buf[65];

	if (argc > 1) {
		if (strcmp(argv[1], "-c") == 0) {
			if (argc < 3) {
				USAGE_COMPARE;
				return -1;
			}

			if (strlen(argv[2]) != 32) {
				fprintf(stderr, "WARNING: MD5 hash size is wrong.\n");
				return -1;
			}

			CHECK_FOR_MD5SUM(argv[3]);

			if (!strcasecmp(md5sum, argv[2])) {
				fprintf(stderr, "%s: OK\n", argv[3]);
				return 0;
			} else {
				fprintf(stderr, "%s: FAILED.  Checksum is %s\n", argv[3], md5sum);
				return -1;
			}
		} else {
			if (argc < 2) {
				USAGE;
				return -1;
			}

			CHECK_FOR_MD5SUM(argv[1]);

			fprintf(stderr, "%s\n", md5sum);
			return 0;
		}
	}
	USAGE;
	USAGE_COMPARE;
	return -1;
}

md5hl.c

/* mdXhl.c * ----------------------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 42):
 * <[email protected]> wrote this file.  As long as you retain this notice you
 * can do whatever you want with this stuff. If we meet some day, and you think
 * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
 * ----------------------------------------------------------------------------
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>

#define LENGTH 16

#include "./md5.h"

char *
MD5End(MD5_CTX *ctx, char *buf)
{
	int i;
	unsigned char digest[LENGTH];
	static const char hex[]="0123456789abcdef";

	if (!buf)
		buf = malloc(2*LENGTH + 1);
	if (!buf)
		return 0;
	MD5Final(digest, ctx);
	for (i = 0; i < LENGTH; i++) {
		buf[i+i] = hex[digest[i] >> 4];
		buf[i+i+1] = hex[digest[i] & 0x0f];
	}
	buf[i+i] = '\0';
	return buf;
}

char *
MD5File(const char *filename, char *buf)
{
	return (MD5FileChunk(filename, buf, 0, 0));
}

char *
MD5FileChunk(const char *filename, char *buf, off_t ofs, off_t len)
{
	unsigned char buffer[BUFSIZ];
	MD5_CTX ctx;
	struct stat stbuf;
	int f, i, e;
	off_t n;

	MD5Init(&ctx);
	f = open(filename, O_RDONLY);
	if (f < 0)
		return 0;
	if (fstat(f, &stbuf) < 0)
		return 0;
	if (ofs > stbuf.st_size)
		ofs = stbuf.st_size;
	if ((len == 0) || (len > stbuf.st_size - ofs))
		len = stbuf.st_size - ofs;
	if (lseek(f, ofs, SEEK_SET) < 0)
		return 0;
	n = len;
	i = 0;
	while (n > 0) {
		if (sizeof(n) > sizeof(buffer))
			i = read(f, buffer, sizeof(buffer));
		else
			i = read(f, buffer, n);
		if (i < 0) 
			break;
		MD5Update(&ctx, buffer, i);
		n -= i;
	} 
	e = errno;
	close(f);
	errno = e;
	if (i < 0)
		return 0;
	return (MD5End(&ctx, buf));
}

char *
MD5Data (const void *data, unsigned int len, char *buf)
{
	MD5_CTX ctx;

	MD5Init(&ctx);
	MD5Update(&ctx,data,len);
	return (MD5End(&ctx, buf));
}