/* MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm
*/

/* 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.
*/

/* do i need all of this just for htonl()? damn. */
#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>

#include "md5global.h"
#include "md5.h"
#include "hmac-md5.h"

/* 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 PROTO_LIST ((UINT4 [4], unsigned char [64]));
static void Encode PROTO_LIST
       ((unsigned char *, UINT4 *, unsigned int)); 
static void Decode PROTO_LIST
       ((UINT4 *, unsigned char *, unsigned int)); 
static void MD5_memcpy PROTO_LIST ((POINTER, POINTER, unsigned int));
static void MD5_memset PROTO_LIST ((POINTER, int, 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.

        */
#ifdef I
/* This might be defined via NANA */
#undef I
#endif

#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 (context)
MD5_CTX *context; /* 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 (context, input, inputLen)
MD5_CTX *context; /* context */
unsigned char *input; /* input block */
unsigned int inputLen; /* length of input block */
{
       unsigned int i, index, partLen; 

         /* Compute number of bytes mod 64 */
         index = (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 - index; 

         /* Transform as many times as possible.

*/
       if (inputLen >= partLen) { 
       MD5_memcpy 
       ((POINTER)&context->buffer[index], (POINTER)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
        ((POINTER)&context->buffer[index], (POINTER)&input[i],
         inputLen-i);

}

/* MD5 finalization. Ends an MD5 message-digest operation, writing the
       the message digest and zeroizing the context. 

        */

void MD5Final (digest, context)
unsigned char digest[16]; /* message digest */
MD5_CTX *context; /* context */
{
       unsigned char bits[8]; 
       unsigned int index, padLen; 

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

         /* Pad out to 56 mod 64.

*/
       index = (unsigned int)((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 ((POINTER)context, 0, sizeof (*context)); 
}

/* MD5 basic transformation. Transforms state based on block.

        */

static void MD5Transform (state, block)
UINT4 state[4];
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.
	 */
       MD5_memset ((POINTER)x, 0, sizeof (x)); 
}

/* Encodes input (UINT4) into output (unsigned char). Assumes len is
       a multiple of 4. 

        */

static void Encode (output, input, len)
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 (output, input, len)
UINT4 *output;
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); 
}

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

        */

static void MD5_memcpy (output, input, len)
POINTER output;
POINTER input;
unsigned int len;
{
       unsigned int i; 

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

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

static void MD5_memset (output, value, len)
POINTER output;
int value;
unsigned int len;
{
       unsigned int i; 

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

void hmac_md5_init(HMAC_MD5_CTX *hmac,
		   const unsigned char *key,
		   int key_len)
{
  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
   * opad is the byte 0x5c repeated 64 times
   * and text is the data being protected
   */

  /* start out by storing key in pads */
  MD5_memset(k_ipad, '\0', sizeof k_ipad);
  MD5_memset(k_opad, '\0', sizeof k_opad);
  MD5_memcpy( k_ipad, key, key_len);
  MD5_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;
  }

  MD5Init(&hmac->ictx);                   /* init inner context */
  MD5Update(&hmac->ictx, k_ipad, 64);     /* apply inner pad */

  MD5Init(&hmac->octx);                   /* init outer context */
  MD5Update(&hmac->octx, k_opad, 64);     /* apply outer pad */

  /* scrub the pads and key context (if used) */
  MD5_memset(&k_ipad, 0, sizeof(k_ipad));
  MD5_memset(&k_opad, 0, sizeof(k_opad));
  MD5_memset(&tk, 0, sizeof(tk));

  /* and we're done. */
}

/* The precalc and import routines here rely on the fact that we pad
 * the key out to 64 bytes and use that to initialize the md5
 * contexts, and that updating an md5 context with 64 bytes of data
 * leaves nothing left over; all of the interesting state is contained
 * in the state field, and none of it is left over in the count and
 * buffer fields.  So all we have to do is save the state field; we
 * can zero the others when we reload it.  Which is why the decision
 * was made to pad the key out to 64 bytes in the first place. */
void hmac_md5_precalc(HMAC_MD5_STATE *state,
		      const unsigned char *key,
		      int key_len)
{
  HMAC_MD5_CTX hmac;
  unsigned lupe;

  hmac_md5_init(&hmac, key, key_len);
  for (lupe = 0; lupe < 4; lupe++) {
    state->istate[lupe] = htonl(hmac.ictx.state[lupe]);
    state->ostate[lupe] = htonl(hmac.octx.state[lupe]);
  }
  MD5_memset(&hmac, 0, sizeof(hmac));
}


void hmac_md5_import(HMAC_MD5_CTX *hmac,
		     HMAC_MD5_STATE *state)
{
  unsigned lupe;
  MD5_memset(hmac, 0, sizeof(HMAC_MD5_CTX));
  for (lupe = 0; lupe < 4; lupe++) {
    hmac->ictx.state[lupe] = ntohl(state->istate[lupe]);
    hmac->octx.state[lupe] = ntohl(state->ostate[lupe]);
  }
  /* Init the counts to account for our having applied
   * 64 bytes of key; this works out to 0x200 (64 << 3; see
   * MD5Update above...) */
  hmac->ictx.count[0] = hmac->octx.count[0] = 0x200;
}

void hmac_md5_final(unsigned char digest[HMAC_MD5_SIZE],
		    HMAC_MD5_CTX *hmac)
{
  MD5Final(digest, &hmac->ictx);  /* Finalize inner md5 */
  MD5Update(&hmac->octx, digest, 16); /* Update outer ctx */
  MD5Final(digest, &hmac->octx); /* Finalize outer md5 */
}


void hmac_md5(text, text_len, key, key_len, digest)
const unsigned char* text; /* pointer to data stream */
int text_len; /* length of data stream */
const unsigned char* key; /* pointer to authentication key */
int key_len; /* length of authentication key */
unsigned char *digest; /* caller digest to be filled in */
{
  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
   * opad is the byte 0x5c repeated 64 times
   * and text is the data being protected
   */

  /* start out by storing key in pads */
  MD5_memset(k_ipad, '\0', sizeof k_ipad);
  MD5_memset(k_opad, '\0', sizeof k_opad);
  MD5_memcpy( k_ipad, key, key_len);
  MD5_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, 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 */

}