md5.c

/*\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
  MD5.C

  Designed by Dennis Tseng on June 1, 2002
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\*/

#include 		"common.h"
#include 		"md5.h"

#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(U32[], U8[]);
static void 	MD5_encode(U8*, U32*, U16);
static void 	MD5_decode(U32*, U8*, U16);
static void 	MD5_memcpy(U8*, U8*, U16);
static void 	MD5_memset(U8*, U16, U16);

static U8	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 Ii(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) + (U32)(ac); \
 	(a) = ROTATE_LEFT ((a), (s)); \
 	(a) += (b); \
}

#define GG(a, b, c, d, x, s, ac){ \
 	(a) += G((b), (c), (d)) + (x) + (U32)(ac); \
 	(a) = ROTATE_LEFT ((a), (s)); \
 	(a) += (b); \
}

#define HH(a, b, c, d, x, s, ac){ \
 	(a) += H((b), (c), (d)) + (x) + (U32)(ac); \
 	(a) = ROTATE_LEFT ((a), (s)); \
 	(a) += (b); \
}

#define II(a, b, c, d, x, s, ac){ \
 	(a) += Ii((b), (c), (d)) + (x) + (U32)(ac); \
 	(a) = ROTATE_LEFT ((a), (s)); \
 	(a) += (b); \
}

/****************************************************************
 * Function: hmac_md5
 *
 * input : text, text_len, key, key_len
 * output: digest
 * return:		
 ****************************************************************/
void hmac_md5(U8 *text, int text_len, U8 *key, int key_len, U8 *digest)
{
	MD5_CTX context;
	unsigned char k_ipad[65]; //inner padding - key XORd with ipad
	unsigned char k_opad[65]; //outer padding - key XORd with opad
	unsigned char tk[16];
	int i;
	
	
	/* if key is longer than 64 bytes reset it to key=MD5(key) */
	if (key_len > 64) {
		MD5_CTX tctx;
		MD5Init(&tctx);
		MD5Update(&tctx, key, key_len);
		MD5Final(tk, &tctx);
		key = tk;
		key_len = 16;
	}
	
	/*
	* the HMAC_MD5 transform looks like:
	*
	* MD5(K XOR opad, MD5(K XOR ipad, text))
	*
	* where K is an n byte key
	* ipad is the byte 0x36 repeated 64 times
	Krawczyk, et. al. Informational [Page 8]
	RFC 2104 HMAC February 1997
	* opad is the byte 0x5c repeated 64 times
	* and text is the data being protected
	*/
	
	/* start out by storing key in pads */
	bzero( k_ipad, sizeof k_ipad);
	bzero( k_opad, sizeof k_opad);
	bcopy( key, k_ipad, key_len);
	bcopy( key, k_opad, key_len);
	
	/* XOR key with ipad and opad values */
	for(i=0; i<64; i++) {
		k_ipad[i] ^= 0x36;
		k_opad[i] ^= 0x5c;
	}
	
	/*
	* perform inner MD5
	*/
	MD5Init(&context); /* init context for 1st pass */
	MD5Update(&context, k_ipad, 64); /* start with inner pad */
	MD5Update(&context, text, text_len); /* then text of datagram */
	MD5Final(digest, &context); /* finish up 1st pass */

	/*
	* perform outer MD5
	*/
	MD5Init(&context); /* init context for 2nd pass */
	MD5Update(&context, k_opad, 64); /* start with outer pad */
	MD5Update(&context, digest, 16); /* then results of 1st hash */
	MD5Final(digest, &context); /* finish up 2nd pass */
}

/*********************************************************************
 * MD5digest:
 *
 * This is the final interface for application call
 * input  : str, len
 * output : digest
 *********************************************************************/
void MD5digest(U8 digest[], U8 *str, U16 len)
{ 
    MD5_CTX  context;
    
	MD5Init(&context);
	MD5Update(&context, str, len);
	MD5Final(digest, &context);
}  		

/*********************************************************************
 * MD5Init:
 *
 * 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;
}

/******************************************************************
 * MD5Update:
 *
 * MD5 block update operation. Continues an MD5 message-digest
 * operation, processing another message block, and updating the
 * context.
 ******************************************************************/
void MD5Update(MD5_CTX *context, U8 *input, U16 inputLen)
{
  	U16 i,index,partLen;

  	/* Compute number of bytes mod 64 */
  	index = (U16)((context->count[0] >> 3) & 0x3F);

  	/* Update number of bits */
  	if ((context->count[0] += ((U32)inputLen << 3)) < ((U32)inputLen << 3))
 		context->count[1]++;
 		
  	context->count[1] += ((U32)inputLen >> 29);

  	partLen = 64 - index;

  	/* Transform as many times as possible. */
  	if (inputLen >= partLen){
 		MD5_memcpy((U8*)&context->buffer[index], (U8*)input, partLen);
 		MD5Transform (context->state, context->buffer);

 		for(i=partLen; i + 63 < inputLen; i+=64)
   			MD5Transform (context->state, &input[i]);
 			index = 0;
	}
	else
 		i = 0;

  	/* Buffer remaining input */
  	MD5_memcpy((U8*)&context->buffer[index], (U8*)&input[i], inputLen-i);
}

/******************************************************************
 * MD5Final:
 *
 * Ends an MD5 message-digest operation, writing the
 * the message digest and zeroizing the context.
 *
 * input : digest[16]
 * output:
 ******************************************************************/
void MD5Final(U8 digest[], MD5_CTX *context)
{
  	U8  bits[8];
  	U16 index, padLen;

  	/* Save number of bits */
  	MD5_encode(bits, context->count, 8);

  	/* Pad out to 56 mod 64. */
  	index = (U16)((context->count[0] >> 3) & 0x3f);
  	padLen = (index < 56) ? (56 - index) : (120 - index);
  	MD5Update(context, PADDING, padLen);

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

  	/* Store state in digest */
  	MD5_encode(digest, context->state, 16);

  	/* Zeroize sensitive information */
  	MD5_memset((U8*)context, 0, sizeof (*context));
}

/*************************************************************
 * MD5 basic transformation. Transforms state based on block.
 *
 * U32 state[4];
 * U8  block[64];
 *************************************************************/
static void  MD5Transform(U32 state[], U8 block[])
{
	U32 a=state[0], 
		b=state[1], 
		c=state[2], 
		d=state[3], 
		x[16];

  	MD5_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. */
  	MD5_memset ((U8*)x, 0, sizeof (x));
}

/*------------------------------------------------------------
 * Encodes input (U32) into output (U8). Assumes len is
 * a multiple of 4.
 *-----------------------------------------------------------*/
static void MD5_encode(U8 *output, U32 *input, U16 len)
{
	U16	i,j;

  	for (i=0, j=0; j<len; i++,j+=4){
 		output[j] = (U8)(input[i] & 0xff);
 		output[j+1] = (U8)((input[i] >> 8) & 0xff);
 		output[j+2] = (U8)((input[i] >> 16) & 0xff);
 		output[j+3] = (U8)((input[i] >> 24) & 0xff);
  	}
}

/*------------------------------------------------------------
 * Decodes input (U8) into output (U32). Assumes len is
 * a multiple of 4.
 *-----------------------------------------------------------*/
static void MD5_decode(U32 *output, U8 *input, U16 len)
{
  	U16	i,j;

  	for(i=0,j=0; j<len; i++,j+=4){
 		output[i] = ((U32)input[j]) | (((U32)input[j+1]) << 8) |
   		(((U32)input[j+2]) << 16) | (((U32)input[j+3]) << 24);
   	}
}

/*---------------------------------------------------------------
 * Note: Replace "for loop" with standard memcpy if possible.
 *--------------------------------------------------------------*/
static void MD5_memcpy(U8 *output, U8 *input, U16 len)
{
	U16 i;

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

/*---------------------------------------------------------------
 * Note: Replace "for loop" with standard memset if possible.
 *--------------------------------------------------------------*/
static void  MD5_memset(U8 *output, U16 value, U16 len)
{
  	U16 i;

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