/* @(#)md5c.c	1.4 06/05/02 Copyright 1998,1999 Heiko Eissfeldt */
#ifndef lint
static char	sccsid[] =
"@(#)md5c.c	1.4 06/05/02 Copyright 1998,1999 Heiko Eissfeldt";

#endif
/*
 * 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.
 */

#include "config.h"
#include "mytype.h"
#include "md5.h"

/*
 * Constants for MD5Transform routine.
 */
#define	S11	7L
#define	S12	12L
#define	S13	17L
#define	S14	22L
#define	S21	5L
#define	S22	9L
#define	S23	14L
#define	S24	20L
#define	S31	4L
#define	S32	11L
#define	S33	16L
#define	S34	23L
#define	S41	6L
#define	S42	10L
#define	S43	15L
#define	S44	21L

typedef unsigned char	*POINTER;

static void	MD5Transform	__PR((UINT4 [4], unsigned char [64]));
static void	Encode		__PR((unsigned char *, UINT4 *, unsigned int));
static void	Decode		__PR((UINT4 *, unsigned char *, unsigned int));
static void	MD5_memcpy	__PR((POINTER, POINTER, unsigned int));
static void	MD5_memset	__PR((POINTER, int, unsigned int));

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) >> (32L-(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) + (UINT4)(ac); \
	(a) = ROTATE_LEFT((a), (s)); \
	(a) += (b); \
}
#define	GG(a, b, c, d, x, s, ac) { \
	(a) += G((b), (c), (d)) + (x) + (UINT4)(ac); \
	(a) = ROTATE_LEFT((a), (s)); \
	(a) += (b); \
}
#define	HH(a, b, c, d, x, s, ac) { \
	(a) += H((b), (c), (d)) + (x) + (UINT4)(ac); \
	(a) = ROTATE_LEFT((a), (s)); \
	(a) += (b); \
}
#define	II(a, b, c, d, x, s, ac) { \
	(a) += I((b), (c), (d)) + (x) + (UINT4)(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 */
{
	context->count[0] = context->count[1] = 0;
	/*
	 * Load magic initialization constants.
	 */
	context->state[0] = UINT4_C(0x67452301);
	context->state[1] = UINT4_C(0xefcdab89);
	context->state[2] = UINT4_C(0x98badcfe);
	context->state[3] = UINT4_C(0x10325476);
}

/*
 * MD5 block update operation. Continues an MD5 message-digest
 * operation, processing another message block, and updating the
 * context.
 */
void
MD5Update(context, input, inputLen)
	MD5_CTX		*context;	/* context */
	unsigned char	*input;		/* input block */
	unsigned int	inputLen;	/* length of input block */
{
	unsigned int	i;
	unsigned int	indx;
	unsigned int	partLen;

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

	/*
	 * Update number of bits
	 */
	if ((context->count[0] += ((UINT4)inputLen << 3L))
				< ((UINT4)inputLen << 3L))
		context->count[1]++;

	context->count[1] += ((UINT4)inputLen >> 29L);

	partLen = 64 - indx;

	/*
	 * Transform as many times as possible.
	 */
	if (inputLen >= partLen) {
		MD5_memcpy((POINTER)&context->buffer[indx],
					(POINTER)input, partLen);
		MD5Transform(context->state, context->buffer);

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

		indx = 0;
	} else
		i = 0;

	/*
	 * Buffer remaining input
	 */
	MD5_memcpy((POINTER)&context->buffer[indx],
			(POINTER)&input[i],
			inputLen-i);
}

/*
 * 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];	/* message digest */
	MD5_CTX		*context;	/* context */
{
	unsigned char	bits[8];
	unsigned int	indx;
	unsigned int	padLen;

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

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

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

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

	/*
	 * Zeroize sensitive information.
	 */
	MD5_memset((POINTER)context, 0, sizeof (*context));
}

/*
 * MD5 basic transformation. Transforms state based on block.
 */
static void
MD5Transform(state, block)
	UINT4		state[4];
	unsigned char	block[64];
{
	UINT4	a = state[0], b = state[1], c = state[2], d = state[3], x[16];

	Decode(x, block, 64);

	/*
	 * Round 1
	 */
	FF(a, b, c, d, x[ 0], S11, UINT4_C(0xd76aa478)); /* 1 */
	FF(d, a, b, c, x[ 1], S12, UINT4_C(0xe8c7b756)); /* 2 */
	FF(c, d, a, b, x[ 2], S13, UINT4_C(0x242070db)); /* 3 */
	FF(b, c, d, a, x[ 3], S14, UINT4_C(0xc1bdceee)); /* 4 */
	FF(a, b, c, d, x[ 4], S11, UINT4_C(0xf57c0faf)); /* 5 */
	FF(d, a, b, c, x[ 5], S12, UINT4_C(0x4787c62a)); /* 6 */
	FF(c, d, a, b, x[ 6], S13, UINT4_C(0xa8304613)); /* 7 */
	FF(b, c, d, a, x[ 7], S14, UINT4_C(0xfd469501)); /* 8 */
	FF(a, b, c, d, x[ 8], S11, UINT4_C(0x698098d8)); /* 9 */
	FF(d, a, b, c, x[ 9], S12, UINT4_C(0x8b44f7af)); /* 10 */
	FF(c, d, a, b, x[10], S13, UINT4_C(0xffff5bb1)); /* 11 */
	FF(b, c, d, a, x[11], S14, UINT4_C(0x895cd7be)); /* 12 */
	FF(a, b, c, d, x[12], S11, UINT4_C(0x6b901122)); /* 13 */
	FF(d, a, b, c, x[13], S12, UINT4_C(0xfd987193)); /* 14 */
	FF(c, d, a, b, x[14], S13, UINT4_C(0xa679438e)); /* 15 */
	FF(b, c, d, a, x[15], S14, UINT4_C(0x49b40821)); /* 16 */

	/*
	 * Round 2
	 */
	GG(a, b, c, d, x[ 1], S21, UINT4_C(0xf61e2562)); /* 17 */
	GG(d, a, b, c, x[ 6], S22, UINT4_C(0xc040b340)); /* 18 */
	GG(c, d, a, b, x[11], S23, UINT4_C(0x265e5a51)); /* 19 */
	GG(b, c, d, a, x[ 0], S24, UINT4_C(0xe9b6c7aa)); /* 20 */
	GG(a, b, c, d, x[ 5], S21, UINT4_C(0xd62f105d)); /* 21 */
	GG(d, a, b, c, x[10], S22, UINT4_C(0x2441453));  /* 22 */
	GG(c, d, a, b, x[15], S23, UINT4_C(0xd8a1e681)); /* 23 */
	GG(b, c, d, a, x[ 4], S24, UINT4_C(0xe7d3fbc8)); /* 24 */
	GG(a, b, c, d, x[ 9], S21, UINT4_C(0x21e1cde6)); /* 25 */
	GG(d, a, b, c, x[14], S22, UINT4_C(0xc33707d6)); /* 26 */
	GG(c, d, a, b, x[ 3], S23, UINT4_C(0xf4d50d87)); /* 27 */
	GG(b, c, d, a, x[ 8], S24, UINT4_C(0x455a14ed)); /* 28 */
	GG(a, b, c, d, x[13], S21, UINT4_C(0xa9e3e905)); /* 29 */
	GG(d, a, b, c, x[ 2], S22, UINT4_C(0xfcefa3f8)); /* 30 */
	GG(c, d, a, b, x[ 7], S23, UINT4_C(0x676f02d9)); /* 31 */
	GG(b, c, d, a, x[12], S24, UINT4_C(0x8d2a4c8a)); /* 32 */

	/*
	 * Round 3
	 */
	HH(a, b, c, d, x[ 5], S31, UINT4_C(0xfffa3942)); /* 33 */
	HH(d, a, b, c, x[ 8], S32, UINT4_C(0x8771f681)); /* 34 */
	HH(c, d, a, b, x[11], S33, UINT4_C(0x6d9d6122)); /* 35 */
	HH(b, c, d, a, x[14], S34, UINT4_C(0xfde5380c)); /* 36 */
	HH(a, b, c, d, x[ 1], S31, UINT4_C(0xa4beea44)); /* 37 */
	HH(d, a, b, c, x[ 4], S32, UINT4_C(0x4bdecfa9)); /* 38 */
	HH(c, d, a, b, x[ 7], S33, UINT4_C(0xf6bb4b60)); /* 39 */
	HH(b, c, d, a, x[10], S34, UINT4_C(0xbebfbc70)); /* 40 */
	HH(a, b, c, d, x[13], S31, UINT4_C(0x289b7ec6)); /* 41 */
	HH(d, a, b, c, x[ 0], S32, UINT4_C(0xeaa127fa)); /* 42 */
	HH(c, d, a, b, x[ 3], S33, UINT4_C(0xd4ef3085)); /* 43 */
	HH(b, c, d, a, x[ 6], S34, UINT4_C(0x4881d05));  /* 44 */
	HH(a, b, c, d, x[ 9], S31, UINT4_C(0xd9d4d039)); /* 45 */
	HH(d, a, b, c, x[12], S32, UINT4_C(0xe6db99e5)); /* 46 */
	HH(c, d, a, b, x[15], S33, UINT4_C(0x1fa27cf8)); /* 47 */
	HH(b, c, d, a, x[ 2], S34, UINT4_C(0xc4ac5665)); /* 48 */

	/*
	 * Round 4
	 */
	II(a, b, c, d, x[ 0], S41, UINT4_C(0xf4292244)); /* 49 */
	II(d, a, b, c, x[ 7], S42, UINT4_C(0x432aff97)); /* 50 */
	II(c, d, a, b, x[14], S43, UINT4_C(0xab9423a7)); /* 51 */
	II(b, c, d, a, x[ 5], S44, UINT4_C(0xfc93a039)); /* 52 */
	II(a, b, c, d, x[12], S41, UINT4_C(0x655b59c3)); /* 53 */
	II(d, a, b, c, x[ 3], S42, UINT4_C(0x8f0ccc92)); /* 54 */
	II(c, d, a, b, x[10], S43, UINT4_C(0xffeff47d)); /* 55 */
	II(b, c, d, a, x[ 1], S44, UINT4_C(0x85845dd1)); /* 56 */
	II(a, b, c, d, x[ 8], S41, UINT4_C(0x6fa87e4f)); /* 57 */
	II(d, a, b, c, x[15], S42, UINT4_C(0xfe2ce6e0)); /* 58 */
	II(c, d, a, b, x[ 6], S43, UINT4_C(0xa3014314)); /* 59 */
	II(b, c, d, a, x[13], S44, UINT4_C(0x4e0811a1)); /* 60 */
	II(a, b, c, d, x[ 4], S41, UINT4_C(0xf7537e82)); /* 61 */
	II(d, a, b, c, x[11], S42, UINT4_C(0xbd3af235)); /* 62 */
	II(c, d, a, b, x[ 2], S43, UINT4_C(0x2ad7d2bb)); /* 63 */
	II(b, c, d, a, x[ 9], S44, UINT4_C(0xeb86d391)); /* 64 */

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

	/*
	 * Zeroize sensitive information.
	 */
	MD5_memset((POINTER)x, 0, sizeof (x));
}

/*
 * Encodes input (UINT4) into output (unsigned char). Assumes len is
 * a multiple of 4.
 */
static void
Encode(output, input, len)
	unsigned char	*output;
	UINT4		*input;
	unsigned int	len;
{
	unsigned int	i;
	unsigned int	j;

	for (i = 0, j = 0; j < len; i++, j += 4) {
		output[j] = (unsigned char)(input[i] & 0xff);
		output[j+1] = (unsigned char)((input[i] >> 8L) & 0xff);
		output[j+2] = (unsigned char)((input[i] >> 16L) & 0xff);
		output[j+3] = (unsigned char)((input[i] >> 24L) & 0xff);
	}
}

/*
 * Decodes input (unsigned char) into output (UINT4). Assumes len is
 * a multiple of 4.
 */
static void
Decode(output, input, len)
	UINT4	*output;
	unsigned char	*input;
	unsigned int	len;
{
	unsigned int	i;
	unsigned int	j;

	for (i = 0, j = 0; j < len; i++, j += 4) {
		output[i] = ((UINT4)input[j]) |
			    (((UINT4)input[j+1]) << 8L) |
			    (((UINT4)input[j+2]) << 16L) |
			    (((UINT4)input[j+3]) << 24L);
	}
}

/*
 * Note: Replace "for loop" with standard memcpy if possible.
 */
static void
MD5_memcpy(output, input, len)
	POINTER		output;
	POINTER		input;
	unsigned int	len;
{
	unsigned int	i;

	for (i = 0; i < len; i++)
		output[i] = input[i];
}

/*
 * Note: Replace "for loop" with standard memset if possible.
 */
static void
MD5_memset(output, value, len)
	POINTER		output;
	int		value;
	unsigned int	len;
{
	unsigned int	i;

	for (i = 0; i < len; i++)
		((char *)output)[i] = (char)value;
}
