/*	$NetBSD: md5c.c,v 1.5 2012/03/20 16:21:41 matt Exp $	*/

/*
 * This file is derived from the RSA Data Security, Inc. MD5 Message-Digest
 * Algorithm and has been modified by Jason R. Thorpe <thorpej@NetBSD.org>
 * for portability and formatting.
 */

/*
 * 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.
 */

#if defined(_KERNEL) || defined(_STANDALONE)
#include <sys/param.h>
#include <sys/md5.h>
#include <lib/libkern/libkern.h>
#else
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: md5c.c,v 1.5 2012/03/20 16:21:41 matt Exp $");
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/types.h>
#include <assert.h>
#include <string.h>
#include <md5.h>
#endif /* _KERNEL || _STANDALONE */

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#if !HAVE_MD5_H

#define	ZEROIZE(d, l)		memset((d), 0, (l))

typedef unsigned char *POINTER;
typedef uint16_t UINT2;
typedef uint32_t UINT4;

/*
 * 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

#if !defined(_KERNEL) && !defined(_STANDALONE) && defined(__weak_alias)
__weak_alias(MD5Init,_MD5Init)
__weak_alias(MD5Update,_MD5Update)
__weak_alias(MD5Final,_MD5Final)
__weak_alias(MD5Transform,_MD5Transform)
#endif

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);

/*
 * 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);
}

static const 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)
{

	_DIAGASSERT(context != 0);

	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,
	const unsigned char *input,	/* input block */
	unsigned int inputLen)		/* length of input block */
{
	unsigned int i, idx, partLen;

	_DIAGASSERT(context != 0);
	_DIAGASSERT(input != 0);

	/* Compute number of bytes mod 64 */
	idx = (unsigned int)((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 - idx;

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

/*
 * MD5 finalization.  Ends an MD5 message-digest operation, writing the
 * message digest and zeroing the context.
 */
void
MD5Final(unsigned char digest[16],	/* message digest */
	MD5_CTX *context)		/* context */
{
	unsigned char bits[8];
	unsigned int idx, padLen;

	_DIAGASSERT(digest != 0);
	_DIAGASSERT(context != 0);

	/* 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);

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

	/* Zeroize sensitive information. */
	ZEROIZE((POINTER)(void *)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. */
	ZEROIZE((POINTER)(void *)x, sizeof (x));
}

#endif /* HAVE_MD5_H */