path: root/airpdcap/airpdcap_md5.c

/******************************************************************************/
/*	File includes																					*/
/*																										*/
#include "airpdcap_system.h"
#include "airpdcap_int.h"

#include "airpdcap_md5.h"

#include	"airpdcap_debug.h"
/*																										*/
/******************************************************************************/

/******************************************************************************/
/*	NOTE:	All the code listed here has been taken from IETF RFC 1321 (MD5		*/
/*		functions) and IETF RFC 2104 (HMAC_MD5 function). Refer to that			*/
/*		standard for any further information.												*/
/******************************************************************************/

/******************************************************************************/
/*	Internal definitions																			*/
/*																										*/
#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
/*																										*/
/******************************************************************************/

/******************************************************************************/
/*	Internal macros																				*/
/*																										*/
/* 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) + (ULONG)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define GG(a, b, c, d, x, s, ac) { \
	(a) += G ((b), (c), (d)) + (x) + (ULONG)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define HH(a, b, c, d, x, s, ac) { \
	(a) += H ((b), (c), (d)) + (x) + (ULONG)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define II(a, b, c, d, x, s, ac) { \
	(a) += I ((b), (c), (d)) + (x) + (ULONG)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
/*																										*/
/******************************************************************************/

/******************************************************************************/
/*	Internal type definitions																	*/
/*																										*/
/* MD5 context. */
typedef struct {
	ULONG state[4];                                   /* state (ABCD) */
	ULONG count[2];        /* number of bits, modulo 2^64 (lsb first) */
	UCHAR buffer[64];                         /* input buffer */
} MD5_CTX;


static UCHAR 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
};
/*																										*/
/******************************************************************************/

/******************************************************************************/
/*	Internal function prototypes declarations												*/
/*																										*/
void MD5Final(
				  UCHAR digest[16],
				  MD5_CTX *context)
				  ;
void MD5Update(
					MD5_CTX *context,
					UCHAR *input,
					UINT inputLen)
					;
void MD5Init(
				 MD5_CTX *context)
				 ;
static void MD5_memset(
							  UCHAR *output,
							  INT value,
							  UINT len)
							  ;
static void MD5_memcpy(
							  UCHAR *output,
							  UCHAR *input,
							  UINT len)
							  ;
static void Decode(
						 ULONG *output,
						 UCHAR *input,
						 UINT len)
						 ;
static void Encode(
						 UCHAR *output,
						 ULONG *input,
						 UINT len)
						 ;
/*																										*/
/******************************************************************************/

/******************************************************************************/
/*	Function definitions																			*/
/*																										*/
/* Encodes input (ULONG) into output (UCHAR). Assumes len is
a multiple of 4.
*/
static void Encode(
						 UCHAR *output,
						 ULONG *input,
						 UINT len)
{
	UINT i, j;

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

/* Decodes input (UCHAR) into output (ULONG). Assumes len is
a multiple of 4.
*/
static void Decode(
						 ULONG *output,
						 UCHAR *input,
						 UINT len)
{
	UINT i, j;

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

/* Note: Replace "for loop" with standard memcpy if possible.
*/

static void MD5_memcpy(
							  UCHAR *output,
							  UCHAR *input,
							  UINT len)
{
	UINT i;

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

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

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

/* MD5 basic transformation. Transforms state based on block.
*/
static void MD5Transform(
								 ULONG state[4],
								 UCHAR block[64])
{
	ULONG 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.
	*/
	MD5_memset ((UCHAR *)x, 0, sizeof (x));
}

/* MD5 initialization. Begins an MD5 operation, writing a new context.
*/
void MD5Init(
				 MD5_CTX *context)
{
	memset(context, 0, sizeof(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,
					UCHAR *input,
					UINT inputLen)
{
	UINT i, index, partLen;

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

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

	partLen = 64 - index;

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

/* MD5 finalization. Ends an MD5 message-digest operation, writing the
the message digest and zeroizing the context.
*/
void MD5Final(
				  UCHAR digest[16],
				  MD5_CTX *context)
{
	UCHAR bits[8];
	UINT index, padLen;

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

	/* Pad out to 56 mod 64.
	*/
	index = (UINT)((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 */
	Encode (digest, context->state, 16);

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

void AirPDcapAlgHmacMd5(
				  UCHAR *key,	/* pointer to authentication key */
				  INT key_len,			/* length of authentication key */
				  const UCHAR *text,	/* pointer to data stream */
				  const INT text_len,			/* length of data stream */
				  UCHAR *digest)		/* caller digest to be filled in */
{
	MD5_CTX context;
	UCHAR k_ipad[65];    /* inner padding -
										  * key XORd with ipad
										  */
	UCHAR k_opad[65];    /* outer padding -
										  * key XORd with opad
										  */
	UCHAR 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
	* opad is the byte 0x5c repeated 64 times
	* and text is the data being protected
	*/

	/* start out by storing key in pads */
	memset( k_ipad, 0, sizeof k_ipad);
	memset( k_opad, 0, sizeof k_opad);
	memcpy( k_ipad, key, key_len);
	memcpy( k_opad, key, 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, (UCHAR *)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 */
}
/*																										*/
/******************************************************************************/