/* 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.
 */

/* "$Revision: 1.5 $" */

#include "dcc_defs.h"
#undef HAVE_MD5
#include "dcc_md5.h"

#undef bcopy
#define bcopy(src,dst,len) memcpy(dst,src,len)
#undef bzero
#define bzero(dst,len) memset(dst,0,len)

/* UINT4 defines a four byte word */
#define UINT4 u_int32_t


#define MD5_memcpy(d,s,l) memcpy(d,s,l)

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

static void MD5Transform(UINT4[4], const unsigned char [64]);
static void Encode(unsigned char *, UINT4 *, unsigned int);
static void Decode(UINT4 *, const unsigned char *, 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) >> (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) + (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(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(MD5_CTX *context,		/* context */
	  const void *input0,		/* input block */
	  unsigned int inputLen)	/* length of input block */
{
	const unsigned char *input = input0;
	unsigned int i, indx, partLen;

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

	/* Update number of bits */
	if ((context->count[0] += ((UINT4)inputLen << 3))
	    < ((UINT4)inputLen << 3))
		context->count[1]++;
	context->count[1] += ((UINT4)inputLen >> 29);

	partLen = 64 - indx;

	/* Transform as many times as possible.
	 */
	if (inputLen >= partLen) {
		bcopy(input, &context->buffer[indx], 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 */
	bcopy(&input[i], &context->buffer[indx], inputLen-i);
}


/* MD5 finalization. Ends an MD5 message-digest operation, writing the
  the message digest and zeroizing the context.
 */
void
MD5Final(MD5_DIGEST digest,		/* message digest */
	 MD5_CTX *context)		/* context */
{
	unsigned char bits[8];
	unsigned int indx, padLen;

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

	/* Pad out to 56 mod 64.
	 */
	indx = (unsigned int)((context->count[0] >> 3) & 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, MD5_DIGEST_LEN);

	/* Zeroize sensitive information.
	 */
	bzero(context, sizeof(*context));
}


/* MD5 basic transformation. Transforms state based on block.
 */
static void
MD5Transform(UINT4 state[4],
	     const 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, 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 */
	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 */
	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 */
	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.
	 */
	bzero(x, sizeof(x));
}


/* Encodes input (UINT4) into output (unsigned char). Assumes len is
 * a multiple of 4.
 */
static void
Encode(unsigned char *output,
       UINT4 *input,
       unsigned int len)
{
	unsigned int i, 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] >> 8) & 0xff);
		output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
		output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
	}
}


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

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