fs/cifs/md5.c - pub/scm/linux/kernel/git/mellanox/linux - Git at Google

 /*
  * This code implements the MD5 message-digest algorithm.
  * The algorithm is due to Ron Rivest.  This code was
  * written by Colin Plumb in 1993, no copyright is claimed.
  * This code is in the public domain; do with it what you wish.
  *
  * Equivalent code is available from RSA Data Security, Inc.
  * This code has been tested against that, and is equivalent,
  * except that you don't need to include two pages of legalese
  * with every copy.
  *
  * To compute the message digest of a chunk of bytes, declare an
  * MD5Context structure, pass it to MD5Init, call MD5Update as
  * needed on buffers full of bytes, and then call MD5Final, which
  * will fill a supplied 16-byte array with the digest.
  */

 /* This code slightly modified to fit into Samba by
    abartlet@samba.org Jun 2001
    and to fit the cifs vfs by
    Steve French sfrench@us.ibm.com */

 #include <linux/string.h>
 #include "md5.h"

 static void MD5Transform(__u32 buf[4], __u32 const in[16]);

 /*
  * Note: this code is harmless on little-endian machines.
  */
 static void
 byteReverse(unsigned char *buf, unsigned longs)
 {
 	__u32 t;
 	do {
 		t = (__u32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
 		    ((unsigned) buf[1] << 8 | buf[0]);
 		*(__u32 *) buf = t;
 		buf += 4;
 	} while (--longs);
 }

 /*
  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
  * initialization constants.
  */
 void
 MD5Init(struct MD5Context *ctx)
 {
 	ctx->buf[0] = 0x67452301;
 	ctx->buf[1] = 0xefcdab89;
 	ctx->buf[2] = 0x98badcfe;
 	ctx->buf[3] = 0x10325476;

 	ctx->bits[0] = 0;
 	ctx->bits[1] = 0;
 }

 /*
  * Update context to reflect the concatenation of another buffer full
  * of bytes.
  */
 void
 MD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len)
 {
 	register __u32 t;

 	/* Update bitcount */

 	t = ctx->bits[0];
 	if ((ctx->bits[0] = t + ((__u32) len << 3)) < t)
 		ctx->bits[1]++;	/* Carry from low to high */
 	ctx->bits[1] += len >> 29;

 	t = (t >> 3) & 0x3f;	/* Bytes already in shsInfo->data */

 	/* Handle any leading odd-sized chunks */

 	if (t) {
 		unsigned char *p = (unsigned char *) ctx->in + t;

 		t = 64 - t;
 		if (len < t) {
 			memmove(p, buf, len);
 			return;
 		}
 		memmove(p, buf, t);
 		byteReverse(ctx->in, 16);
 		MD5Transform(ctx->buf, (__u32 *) ctx->in);
 		buf += t;
 		len -= t;
 	}
 	/* Process data in 64-byte chunks */

 	while (len >= 64) {
 		memmove(ctx->in, buf, 64);
 		byteReverse(ctx->in, 16);
 		MD5Transform(ctx->buf, (__u32 *) ctx->in);
 		buf += 64;
 		len -= 64;
 	}

 	/* Handle any remaining bytes of data. */

 	memmove(ctx->in, buf, len);
 }

 /*
  * Final wrapup - pad to 64-byte boundary with the bit pattern
  * 1 0* (64-bit count of bits processed, MSB-first)
  */
 void
 MD5Final(unsigned char digest[16], struct MD5Context *ctx)
 {
 	unsigned int count;
 	unsigned char *p;

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

 	/* Set the first char of padding to 0x80.  This is safe since there is
 	   always at least one byte free */
 	p = ctx->in + count;
 	*p++ = 0x80;

 	/* Bytes of padding needed to make 64 bytes */
 	count = 64 - 1 - count;

 	/* Pad out to 56 mod 64 */
 	if (count < 8) {
 		/* Two lots of padding:  Pad the first block to 64 bytes */
 		memset(p, 0, count);
 		byteReverse(ctx->in, 16);
 		MD5Transform(ctx->buf, (__u32 *) ctx->in);

 		/* Now fill the next block with 56 bytes */
 		memset(ctx->in, 0, 56);
 	} else {
 		/* Pad block to 56 bytes */
 		memset(p, 0, count - 8);
 	}
 	byteReverse(ctx->in, 14);

 	/* Append length in bits and transform */
 	((__u32 *) ctx->in)[14] = ctx->bits[0];
 	((__u32 *) ctx->in)[15] = ctx->bits[1];

 	MD5Transform(ctx->buf, (__u32 *) ctx->in);
 	byteReverse((unsigned char *) ctx->buf, 4);
 	memmove(digest, ctx->buf, 16);
 	memset(ctx, 0, sizeof(*ctx));	/* In case it's sensitive */
 }

 /* The four core functions - F1 is optimized somewhat */

 /* #define F1(x, y, z) (x & y | ~x & z) */
 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 #define F2(x, y, z) F1(z, x, y)
 #define F3(x, y, z) (x ^ y ^ z)
 #define F4(x, y, z) (y ^ (x | ~z))

 /* This is the central step in the MD5 algorithm. */
 #define MD5STEP(f, w, x, y, z, data, s) \
 	(w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x)

 /*
  * The core of the MD5 algorithm, this alters an existing MD5 hash to
  * reflect the addition of 16 longwords of new data.  MD5Update blocks
  * the data and converts bytes into longwords for this routine.
  */
 static void
 MD5Transform(__u32 buf[4], __u32 const in[16])
 {
 	register __u32 a, b, c, d;

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

 	MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
 	MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
 	MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
 	MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
 	MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
 	MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 	MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 	MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 	MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 	MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 	MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 	MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 	MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 	MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 	MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 	MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

 	MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 	MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 	MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 	MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 	MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 	MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 	MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 	MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 	MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 	MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 	MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 	MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 	MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 	MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 	MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 	MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

 	MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 	MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 	MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 	MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 	MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 	MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 	MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 	MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 	MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 	MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 	MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 	MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 	MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 	MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 	MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 	MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

 	MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 	MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 	MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 	MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 	MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 	MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 	MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 	MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 	MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 	MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 	MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 	MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 	MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 	MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 	MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 	MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

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

 #if 0   /* currently unused */
 /***********************************************************************
  the rfc 2104 version of hmac_md5 initialisation.
 ***********************************************************************/
 static void
 hmac_md5_init_rfc2104(unsigned char *key, int key_len,
 		      struct HMACMD5Context *ctx)
 {
 	int i;

 	/* if key is longer than 64 bytes reset it to key=MD5(key) */
 	if (key_len > 64) {
 		unsigned char tk[16];
 		struct MD5Context tctx;

 		MD5Init(&tctx);
 		MD5Update(&tctx, key, key_len);
 		MD5Final(tk, &tctx);

 		key = tk;
 		key_len = 16;
 	}

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

 	/* XOR key with ipad and opad values */
 	for (i = 0; i < 64; i++) {
 		ctx->k_ipad[i] ^= 0x36;
 		ctx->k_opad[i] ^= 0x5c;
 	}

 	MD5Init(&ctx->ctx);
 	MD5Update(&ctx->ctx, ctx->k_ipad, 64);
 }
 #endif

 /***********************************************************************
  the microsoft version of hmac_md5 initialisation.
 ***********************************************************************/
 void
 hmac_md5_init_limK_to_64(const unsigned char *key, int key_len,
 			 struct HMACMD5Context *ctx)
 {
 	int i;

 	/* if key is longer than 64 bytes truncate it */
 	if (key_len > 64)
 		key_len = 64;

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

 	/* XOR key with ipad and opad values */
 	for (i = 0; i < 64; i++) {
 		ctx->k_ipad[i] ^= 0x36;
 		ctx->k_opad[i] ^= 0x5c;
 	}

 	MD5Init(&ctx->ctx);
 	MD5Update(&ctx->ctx, ctx->k_ipad, 64);
 }

 /***********************************************************************
  update hmac_md5 "inner" buffer
 ***********************************************************************/
 void
 hmac_md5_update(const unsigned char *text, int text_len,
 		struct HMACMD5Context *ctx)
 {
 	MD5Update(&ctx->ctx, text, text_len);	/* then text of datagram */
 }

 /***********************************************************************
  finish off hmac_md5 "inner" buffer and generate outer one.
 ***********************************************************************/
 void
 hmac_md5_final(unsigned char *digest, struct HMACMD5Context *ctx)
 {
 	struct MD5Context ctx_o;

 	MD5Final(digest, &ctx->ctx);

 	MD5Init(&ctx_o);
 	MD5Update(&ctx_o, ctx->k_opad, 64);
 	MD5Update(&ctx_o, digest, 16);
 	MD5Final(digest, &ctx_o);
 }

 /***********************************************************
  single function to calculate an HMAC MD5 digest from data.
  use the microsoft hmacmd5 init method because the key is 16 bytes.
 ************************************************************/
 #if 0 /* currently unused */
 static void
 hmac_md5(unsigned char key[16], unsigned char *data, int data_len,
 	 unsigned char *digest)
 {
 	struct HMACMD5Context ctx;
 	hmac_md5_init_limK_to_64(key, 16, &ctx);
 	if (data_len != 0)
 		hmac_md5_update(data, data_len, &ctx);

 	hmac_md5_final(digest, &ctx);
 }
 #endif
	/*
	* This code implements the MD5 message-digest algorithm.
	* The algorithm is due to Ron Rivest. This code was
	* written by Colin Plumb in 1993, no copyright is claimed.
	* This code is in the public domain; do with it what you wish.
	*
	* Equivalent code is available from RSA Data Security, Inc.
	* This code has been tested against that, and is equivalent,
	* except that you don't need to include two pages of legalese
	* with every copy.
	*
	* To compute the message digest of a chunk of bytes, declare an
	* MD5Context structure, pass it to MD5Init, call MD5Update as
	* needed on buffers full of bytes, and then call MD5Final, which
	* will fill a supplied 16-byte array with the digest.
	*/

	/* This code slightly modified to fit into Samba by
	abartlet@samba.org Jun 2001
	and to fit the cifs vfs by
	Steve French sfrench@us.ibm.com */

	#include <linux/string.h>
	#include "md5.h"

	static void MD5Transform(__u32 buf[4], __u32 const in[16]);

	/*
	* Note: this code is harmless on little-endian machines.
	*/
	static void
	byteReverse(unsigned char *buf, unsigned longs)
	{
	__u32 t;
	do {
	t = (__u32) ((unsigned) buf[3] << 8 \| buf[2]) << 16 \|
	((unsigned) buf[1] << 8 \| buf[0]);
	(__u32 ) buf = t;
	buf += 4;
	} while (--longs);
	}

	/*
	* Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
	* initialization constants.
	*/
	void
	MD5Init(struct MD5Context *ctx)
	{
	ctx->buf[0] = 0x67452301;
	ctx->buf[1] = 0xefcdab89;
	ctx->buf[2] = 0x98badcfe;
	ctx->buf[3] = 0x10325476;

	ctx->bits[0] = 0;
	ctx->bits[1] = 0;
	}

	/*
	* Update context to reflect the concatenation of another buffer full
	* of bytes.
	*/
	void
	MD5Update(struct MD5Context ctx, unsigned char const buf, unsigned len)
	{
	register __u32 t;

	/* Update bitcount */

	t = ctx->bits[0];
	if ((ctx->bits[0] = t + ((__u32) len << 3)) < t)
	ctx->bits[1]++; /* Carry from low to high */
	ctx->bits[1] += len >> 29;

	t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */

	/* Handle any leading odd-sized chunks */

	if (t) {
	unsigned char p = (unsigned char ) ctx->in + t;

	t = 64 - t;
	if (len < t) {
	memmove(p, buf, len);
	return;
	}
	memmove(p, buf, t);
	byteReverse(ctx->in, 16);
	MD5Transform(ctx->buf, (__u32 *) ctx->in);
	buf += t;
	len -= t;
	}
	/* Process data in 64-byte chunks */

	while (len >= 64) {
	memmove(ctx->in, buf, 64);
	byteReverse(ctx->in, 16);
	MD5Transform(ctx->buf, (__u32 *) ctx->in);
	buf += 64;
	len -= 64;
	}

	/* Handle any remaining bytes of data. */

	memmove(ctx->in, buf, len);
	}

	/*
	* Final wrapup - pad to 64-byte boundary with the bit pattern
	* 1 0* (64-bit count of bits processed, MSB-first)
	*/
	void
	MD5Final(unsigned char digest[16], struct MD5Context *ctx)
	{
	unsigned int count;
	unsigned char *p;

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

	/* Set the first char of padding to 0x80. This is safe since there is
	always at least one byte free */
	p = ctx->in + count;
	*p++ = 0x80;

	/* Bytes of padding needed to make 64 bytes */
	count = 64 - 1 - count;

	/* Pad out to 56 mod 64 */
	if (count < 8) {
	/* Two lots of padding: Pad the first block to 64 bytes */
	memset(p, 0, count);
	byteReverse(ctx->in, 16);
	MD5Transform(ctx->buf, (__u32 *) ctx->in);

	/* Now fill the next block with 56 bytes */
	memset(ctx->in, 0, 56);
	} else {
	/* Pad block to 56 bytes */
	memset(p, 0, count - 8);
	}
	byteReverse(ctx->in, 14);

	/* Append length in bits and transform */
	((__u32 *) ctx->in)[14] = ctx->bits[0];
	((__u32 *) ctx->in)[15] = ctx->bits[1];

	MD5Transform(ctx->buf, (__u32 *) ctx->in);
	byteReverse((unsigned char *) ctx->buf, 4);
	memmove(digest, ctx->buf, 16);
	memset(ctx, 0, sizeof(ctx)); / In case it's sensitive */
	}

	/* The four core functions - F1 is optimized somewhat */

	/* #define F1(x, y, z) (x & y \| ~x & z) */
	#define F1(x, y, z) (z ^ (x & (y ^ z)))
	#define F2(x, y, z) F1(z, x, y)
	#define F3(x, y, z) (x ^ y ^ z)
	#define F4(x, y, z) (y ^ (x \| ~z))

	/* This is the central step in the MD5 algorithm. */
	#define MD5STEP(f, w, x, y, z, data, s) \
	(w += f(x, y, z) + data, w = w<<s \| w>>(32-s), w += x)

	/*
	* The core of the MD5 algorithm, this alters an existing MD5 hash to
	* reflect the addition of 16 longwords of new data. MD5Update blocks
	* the data and converts bytes into longwords for this routine.
	*/
	static void
	MD5Transform(__u32 buf[4], __u32 const in[16])
	{
	register __u32 a, b, c, d;

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

	MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
	MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
	MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
	MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
	MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
	MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
	MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
	MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
	MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
	MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
	MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
	MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
	MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
	MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
	MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
	MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

	MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
	MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
	MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
	MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
	MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
	MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
	MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
	MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
	MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
	MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
	MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
	MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
	MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
	MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
	MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
	MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

	MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
	MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
	MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
	MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
	MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
	MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
	MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
	MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
	MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
	MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
	MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
	MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
	MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
	MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
	MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
	MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

	MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
	MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
	MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
	MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
	MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
	MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
	MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
	MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
	MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
	MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
	MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
	MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
	MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
	MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
	MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
	MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

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

	#if 0 /* currently unused */
	/***********************************************************************
	the rfc 2104 version of hmac_md5 initialisation.
	***********************************************************************/
	static void
	hmac_md5_init_rfc2104(unsigned char *key, int key_len,
	struct HMACMD5Context *ctx)
	{
	int i;

	/* if key is longer than 64 bytes reset it to key=MD5(key) */
	if (key_len > 64) {
	unsigned char tk[16];
	struct MD5Context tctx;

	MD5Init(&tctx);
	MD5Update(&tctx, key, key_len);
	MD5Final(tk, &tctx);

	key = tk;
	key_len = 16;
	}

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

	/* XOR key with ipad and opad values */
	for (i = 0; i < 64; i++) {
	ctx->k_ipad[i] ^= 0x36;
	ctx->k_opad[i] ^= 0x5c;
	}

	MD5Init(&ctx->ctx);
	MD5Update(&ctx->ctx, ctx->k_ipad, 64);
	}
	#endif

	/***********************************************************************
	the microsoft version of hmac_md5 initialisation.
	***********************************************************************/
	void
	hmac_md5_init_limK_to_64(const unsigned char *key, int key_len,
	struct HMACMD5Context *ctx)
	{
	int i;

	/* if key is longer than 64 bytes truncate it */
	if (key_len > 64)
	key_len = 64;

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

	/* XOR key with ipad and opad values */
	for (i = 0; i < 64; i++) {
	ctx->k_ipad[i] ^= 0x36;
	ctx->k_opad[i] ^= 0x5c;
	}

	MD5Init(&ctx->ctx);
	MD5Update(&ctx->ctx, ctx->k_ipad, 64);
	}

	/***********************************************************************
	update hmac_md5 "inner" buffer
	***********************************************************************/
	void
	hmac_md5_update(const unsigned char *text, int text_len,
	struct HMACMD5Context *ctx)
	{
	MD5Update(&ctx->ctx, text, text_len); /* then text of datagram */
	}

	/***********************************************************************
	finish off hmac_md5 "inner" buffer and generate outer one.
	***********************************************************************/
	void
	hmac_md5_final(unsigned char digest, struct HMACMD5Context ctx)
	{
	struct MD5Context ctx_o;

	MD5Final(digest, &ctx->ctx);

	MD5Init(&ctx_o);
	MD5Update(&ctx_o, ctx->k_opad, 64);
	MD5Update(&ctx_o, digest, 16);
	MD5Final(digest, &ctx_o);
	}

	/***********************************************************
	single function to calculate an HMAC MD5 digest from data.
	use the microsoft hmacmd5 init method because the key is 16 bytes.
	************************************************************/
	#if 0 /* currently unused */
	static void
	hmac_md5(unsigned char key[16], unsigned char *data, int data_len,
	unsigned char *digest)
	{
	struct HMACMD5Context ctx;
	hmac_md5_init_limK_to_64(key, 16, &ctx);
	if (data_len != 0)
	hmac_md5_update(data, data_len, &ctx);

	hmac_md5_final(digest, &ctx);
	}
	#endif