/* 
** **************************************************************************
** md5.c -- Implementation of MD5 Message Digest Algorithm                 **
** Updated: 2/16/90 by Ronald L. Rivest                                    **
** (C) 1990 RSA Data Security, Inc.                                        **
** **************************************************************************
*/

/* 
** To use MD5:
**   -- Include md5.h in your program
**   -- Declare an MDstruct MD to hold the state of the digest computation.
**   -- Initialize MD using MDbegin(&MD)
**   -- For each full block (64 bytes) X you wish to process, call
**          MDupdate(&MD,X,512)
**      (512 is the number of bits in a full block.)
**   -- For the last block (less than 64 bytes) you wish to process,
**          MDupdate(&MD,X,n)
**      where n is the number of bits in the partial block. A partial
**      block terminates the computation, so every MD computation should
**      terminate by processing a partial block, even if it has n = 0.
**   -- The message digest is available in MD.buffer[0] ... MD.buffer[3].
**      (Least-significant byte of each word should be output first.)
**   -- You can print out the digest using MDprint(&MD)
*/

/* Implementation notes:
** This implementation assumes that ints are 32-bit quantities.
** If the machine stores the least-significant byte of an int in the
** least-addressed byte (eg., VAX and 8086), then LOWBYTEFIRST should be
** set to TRUE.  Otherwise (eg., SUNS), LOWBYTEFIRST should be set to
** FALSE.  Note that on machines with LOWBYTEFIRST FALSE the routine
** MDupdate modifies has a side-effect on its input array (the order of bytes
** in each word are reversed).  If this is undesired a call to MDreverse(X) can
** reverse the bytes of X back into order after each call to MDupdate.
*/

/* code uses WORDS_BIGENDIAN defined by configure now  -- WH 9/27/95 */

/* Compile-time includes 
*/

#include <config.h>

#include <stdio.h>
#include <sys/types.h>
#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#if HAVE_WINSOCK_H
#include <winsock.h>
#endif

#if HAVE_STDLIB_H
#include <stdlib.h>
#endif

#include "md5.h"
#include "tools.h"

/* Compile-time declarations of MD5 ``magic constants''.
*/
#define I0  0x67452301       /* Initial values for MD buffer */
#define I1  0xefcdab89
#define I2  0x98badcfe
#define I3  0x10325476
#define fs1  7               /* round 1 shift amounts */
#define fs2 12   
#define fs3 17  
#define fs4 22  
#define gs1  5               /* round 2 shift amounts */
#define gs2  9   
#define gs3 14   
#define gs4 20  
#define hs1  4               /* round 3 shift amounts */
#define hs2 11 
#define hs3 16 
#define hs4 23
#define is1  6               /* round 4 shift amounts */
#define is2 10
#define is3 15
#define is4 21


/* Compile-time macro declarations for MD5.
** Note: The ``rot'' operator uses the variable ``tmp''.
** It assumes tmp is declared as unsigned int, so that the >>
** operator will shift in zeros rather than extending the sign bit.
*/
#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)))
#define rot(X,S)             (tmp=X,(tmp<<S) | (tmp>>(32-S)))
#define ff(A,B,C,D,i,s,lp)   A = rot((A + f(B,C,D) + X[i] + lp),s) + B
#define gg(A,B,C,D,i,s,lp)   A = rot((A + g(B,C,D) + X[i] + lp),s) + B
#define hh(A,B,C,D,i,s,lp)   A = rot((A + h(B,C,D) + X[i] + lp),s) + B
#define ii(A,B,C,D,i,s,lp)   A = rot((A + i_(B,C,D) + X[i] + lp),s) + B

#ifdef STDC_HEADERS
#define Uns(num) num##U
#else
#define Uns(num) num
#endif /* STDC_HEADERS */

void MDreverse (unsigned int *);
static void MDblock (MDptr, unsigned int *);

#ifdef SNMP_TESTING_CODE
/* MDprint(MDp)
** Print message digest buffer MDp as 32 hexadecimal digits.
** Order is from low-order byte of buffer[0] to high-order byte of buffer[3].
** Each byte is printed with high-order hexadecimal digit first.
** This is a user-callable routine.
*/
void 
MDprint(MDptr MDp)
{ 
    int i,j;
    for (i=0;i<4;i++)
	for (j=0;j<32;j=j+8)
	    printf("%02x",(MDp->buffer[i]>>j) & 0xFF);
    printf("\n");
    fflush(stdout);
}
#endif /* SNMP_TESTING_CODE */

/* MDbegin(MDp)
** Initialize message digest buffer MDp. 
** This is a user-callable routine.
*/
void 
MDbegin(MDptr MDp)
{ 
    int i;
    MDp->buffer[0] = I0;  
    MDp->buffer[1] = I1;  
    MDp->buffer[2] = I2;  
    MDp->buffer[3] = I3; 
    for (i=0;i<8;i++) MDp->count[i] = 0;
    MDp->done = 0;
}

/* MDreverse(X)
** Reverse the byte-ordering of every int in X.
** Assumes X is an array of 16 ints.
** The macro revx reverses the byte-ordering of the next word of X.
*/
#define revx { t = (*X << 16) | (*X >> 16); \
	       *X++ = ((t & 0xFF00FF00) >> 8) | ((t & 0x00FF00FF) << 8); }

void MDreverse(unsigned int *X)
{ 
    register unsigned int t;
    revx; revx; revx; revx; revx; revx; revx; revx;
    revx; revx; revx; revx; revx; revx; revx; revx;
}

/* MDblock(MDp,X)
** Update message digest buffer MDp->buffer using 16-word data block X.
** Assumes all 16 words of X are full of data.
** Does not update MDp->count.
** This routine is not user-callable. 
*/
static void
MDblock(MDptr MDp,
	unsigned int *X)
{ 
    register unsigned int tmp, A, B, C, D;  /* hpux sysv sun */
#ifdef WORDS_BIGENDIAN
    MDreverse(X);
#endif
    A = MDp->buffer[0];
    B = MDp->buffer[1];
    C = MDp->buffer[2];
    D = MDp->buffer[3];
    
    /* Update the message digest buffer */
    ff(A , B , C , D ,  0 , fs1 , Uns(3614090360)); /* Round 1 */
    ff(D , A , B , C ,  1 , fs2 , Uns(3905402710)); 
    ff(C , D , A , B ,  2 , fs3 ,  Uns(606105819)); 
    ff(B , C , D , A ,  3 , fs4 , Uns(3250441966)); 
    ff(A , B , C , D ,  4 , fs1 , Uns(4118548399)); 
    ff(D , A , B , C ,  5 , fs2 , Uns(1200080426)); 
    ff(C , D , A , B ,  6 , fs3 , Uns(2821735955)); 
    ff(B , C , D , A ,  7 , fs4 , Uns(4249261313)); 
    ff(A , B , C , D ,  8 , fs1 , Uns(1770035416)); 
    ff(D , A , B , C ,  9 , fs2 , Uns(2336552879)); 
    ff(C , D , A , B , 10 , fs3 , Uns(4294925233)); 
    ff(B , C , D , A , 11 , fs4 , Uns(2304563134)); 
    ff(A , B , C , D , 12 , fs1 , Uns(1804603682)); 
    ff(D , A , B , C , 13 , fs2 , Uns(4254626195)); 
    ff(C , D , A , B , 14 , fs3 , Uns(2792965006)); 
    ff(B , C , D , A , 15 , fs4 , Uns(1236535329)); 
    gg(A , B , C , D ,  1 , gs1 , Uns(4129170786)); /* Round 2 */
    gg(D , A , B , C ,  6 , gs2 , Uns(3225465664)); 
    gg(C , D , A , B , 11 , gs3 ,  Uns(643717713)); 
    gg(B , C , D , A ,  0 , gs4 , Uns(3921069994)); 
    gg(A , B , C , D ,  5 , gs1 , Uns(3593408605)); 
    gg(D , A , B , C , 10 , gs2 ,   Uns(38016083)); 
    gg(C , D , A , B , 15 , gs3 , Uns(3634488961)); 
    gg(B , C , D , A ,  4 , gs4 , Uns(3889429448)); 
    gg(A , B , C , D ,  9 , gs1 ,  Uns(568446438)); 
    gg(D , A , B , C , 14 , gs2 , Uns(3275163606)); 
    gg(C , D , A , B ,  3 , gs3 , Uns(4107603335)); 
    gg(B , C , D , A ,  8 , gs4 , Uns(1163531501)); 
    gg(A , B , C , D , 13 , gs1 , Uns(2850285829)); 
    gg(D , A , B , C ,  2 , gs2 , Uns(4243563512)); 
    gg(C , D , A , B ,  7 , gs3 , Uns(1735328473)); 
    gg(B , C , D , A , 12 , gs4 , Uns(2368359562));  
    hh(A , B , C , D ,  5 , hs1 , Uns(4294588738)); /* Round 3 */
    hh(D , A , B , C ,  8 , hs2 , Uns(2272392833)); 
    hh(C , D , A , B , 11 , hs3 , Uns(1839030562)); 
    hh(B , C , D , A , 14 , hs4 , Uns(4259657740)); 
    hh(A , B , C , D ,  1 , hs1 , Uns(2763975236)); 
    hh(D , A , B , C ,  4 , hs2 , Uns(1272893353)); 
    hh(C , D , A , B ,  7 , hs3 , Uns(4139469664)); 
    hh(B , C , D , A , 10 , hs4 , Uns(3200236656)); 
    hh(A , B , C , D , 13 , hs1 ,  Uns(681279174)); 
    hh(D , A , B , C ,  0 , hs2 , Uns(3936430074)); 
    hh(C , D , A , B ,  3 , hs3 , Uns(3572445317)); 
    hh(B , C , D , A ,  6 , hs4 ,   Uns(76029189)); 
    hh(A , B , C , D ,  9 , hs1 , Uns(3654602809)); 
    hh(D , A , B , C , 12 , hs2 , Uns(3873151461)); 
    hh(C , D , A , B , 15 , hs3 ,  Uns(530742520)); 
    hh(B , C , D , A ,  2 , hs4 , Uns(3299628645));
    ii(A , B , C , D ,  0 , is1 , Uns(4096336452)); /* Round 4 */
    ii(D , A , B , C ,  7 , is2 , Uns(1126891415));
    ii(C , D , A , B , 14 , is3 , Uns(2878612391));
    ii(B , C , D , A ,  5 , is4 , Uns(4237533241));
    ii(A , B , C , D , 12 , is1 , Uns(1700485571));
    ii(D , A , B , C ,  3 , is2 , Uns(2399980690));
    ii(C , D , A , B , 10 , is3 , Uns(4293915773));
    ii(B , C , D , A ,  1 , is4 , Uns(2240044497));
    ii(A , B , C , D ,  8 , is1 , Uns(1873313359));
    ii(D , A , B , C , 15 , is2 , Uns(4264355552));
    ii(C , D , A , B ,  6 , is3 , Uns(2734768916));
    ii(B , C , D , A , 13 , is4 , Uns(1309151649));
    ii(A , B , C , D ,  4 , is1 , Uns(4149444226));
    ii(D , A , B , C , 11 , is2 , Uns(3174756917));
    ii(C , D , A , B ,  2 , is3 ,  Uns(718787259));
    ii(B , C , D , A ,  9 , is4 , Uns(3951481745));
    
    MDp->buffer[0] += A; 
    MDp->buffer[1] += B;
    MDp->buffer[2] += C;
    MDp->buffer[3] += D; 
#ifdef WORDS_BIGENDIAN
    MDreverse(X);
#endif
}

/* MDupdate(MDp,X,count)
** Input: MDp -- an MDptr
**        X -- a pointer to an array of unsigned characters.
**        count -- the number of bits of X to use.
**                 (if not a multiple of 8, uses high bits of last byte.)
** Update MDp using the number of bits of X given by count.
** This is the basic input routine for an MD5 user.
** The routine completes the MD computation when count < 512, so
** every MD computation should end with one call to MDupdate with a
** count less than 512.  A call with count 0 will be ignored if the
** MD has already been terminated (done != 0), so an extra call with count
** 0 can be given as a ``courtesy close'' to force termination if desired.
** Returns : 0 if processing succeeds or was already done;
**          -1 if processing was already done
**          -2 if count was too large
*/
int 
MDupdate(MDptr MDp,
	 unsigned char *X,
	 unsigned int count)
{ 
    unsigned int i, tmp, bit, byte, mask;
    unsigned char XX[64];
    unsigned char *p;
    /* return with no error if this is a courtesy close with count
  ** zero and MDp->done is true.
  */
    if (count == 0 && MDp->done) return 0;
    /* check to see if MD is already done and report error */
    if (MDp->done) { return -1; }
/*
    if (MDp->done) { fprintf(stderr,"\nError: MDupdate MD already done."); return; }
*/
    /* Add count to MDp->count */
    tmp = count;
    p = MDp->count;
    while (tmp)
    { tmp += *p;
    *p++ = tmp;
    tmp = tmp >> 8;
    }
    /* Process data */
    if (count == 512) 
    { /* Full block of data to handle */
	MDblock(MDp,(unsigned int *)X);
    }
    else if (count > 512) /* Check for count too large */
    return -2;
/*
    { fprintf(stderr,"\nError: MDupdate called with illegal count value %d.",count);
    return;
    }
*/
    else /* partial block -- must be last block so finish up */
    { /* Find out how many bytes and residual bits there are */
        int copycount;
	byte = count >> 3;
	bit =  count & 7;
	copycount = byte; if (bit) copycount++;
	/* Copy X into XX since we need to modify it */
	memset(XX,0,sizeof(XX));
	memcpy(XX,X,copycount);

	/* Add padding '1' bit and low-order zeros in last byte */
	mask = ((unsigned long)1) << (7 - bit);
	XX[byte] = (XX[byte] | mask) & ~( mask - 1);
	/* If room for bit count, finish up with this block */
	if (byte <= 55)
	{ for (i=0;i<8;i++) XX[56+i] = MDp->count[i];
	MDblock(MDp,(unsigned int *)XX);
	}
	else /* need to do two blocks to finish up */
	{ MDblock(MDp,(unsigned int *)XX);
	for (i=0;i<56;i++) XX[i] = 0;
	for (i=0;i<8;i++)  XX[56+i] = MDp->count[i];
	MDblock(MDp,(unsigned int *)XX);
	}
	/* Set flag saying we're done with MD computation */
	MDp->done = 1;
    }
    return 0;
}

/* MDchecksum(data, len, MD5): do a checksum on an arbirtrary amount of data */
int
MDchecksum(u_char *data, size_t len, u_char *mac, size_t maclen)
{
  MDstruct md;
  MDstruct *MD = &md;
  int rc = 0;
  
  MDbegin(MD);
  while (len >= 64) {
    rc = MDupdate(MD, data, 64*8);
    if (rc) goto check_end;
    data += 64;
    len -= 64;
  }
  rc = MDupdate(MD, data, len*8);
  if (rc) goto check_end;

  /* copy the checksum to the outgoing data (all of it that is requested). */
  MDget(MD, mac, maclen);

check_end:
  memset(&md,0,sizeof(md));
  return rc;
}


/* MDsign(data, len, MD5): do a checksum on an arbirtrary amount
   of data, and prepended with a secret in the standard fashion */
int
MDsign(u_char *data, size_t len, u_char *mac, size_t maclen,
       u_char *secret, size_t secretlen)
{
#define HASHKEYLEN 64

  MDstruct MD;
  u_char   K1[HASHKEYLEN];
  u_char   K2[HASHKEYLEN];
  u_char   extendedAuthKey[HASHKEYLEN];
  u_char   buf[HASHKEYLEN];
  size_t   i;
  u_char  *cp, *newdata = 0;
  int      rc = 0;

/*
  memset(K1,0,HASHKEYLEN);
  memset(K2,0,HASHKEYLEN);
  memset(buf,0,HASHKEYLEN);
  memset(extendedAuthKey,0,HASHKEYLEN);
*/

  if (secretlen != 16 || secret == NULL || mac == NULL || data == NULL ||
    len <= 0 || maclen <= 0) {
/*    DEBUGMSGTL(("md5","MD5 signing not properly initialized")); */
    return -1;
  }
  
  memset(extendedAuthKey, 0, HASHKEYLEN);
  memcpy(extendedAuthKey, secret, secretlen);
  for(i = 0; i < HASHKEYLEN; i++) {
    K1[i] = extendedAuthKey[i] ^ 0x36;
    K2[i] = extendedAuthKey[i] ^ 0x5c;
  }

  MDbegin(&MD);
  rc = MDupdate(&MD, K1, HASHKEYLEN*8);
  if (rc) goto update_end;

  i = len;
  if (((unsigned int)data)%32 != 0) {
      /* this relies on the ability to use integer math and thus we
         must rely on data that aligns on 32-bit-word-boundries */
      memdup(&newdata, data, len);
      cp = newdata;
  } else {
      cp = data;
  }
  
  while (i >= 64) {
    rc = MDupdate(&MD, cp, 64*8);
	if (rc) goto update_end;
    cp += 64;
    i -= 64;
  }

  rc = MDupdate(&MD, cp, i*8);
  if (rc) goto update_end;

  memset(buf,0,HASHKEYLEN);
  MDget(&MD, buf, HASHKEYLEN);

  MDbegin(&MD);
  rc = MDupdate(&MD, K2, HASHKEYLEN*8);
  if (rc) goto update_end;
  rc = MDupdate(&MD, buf, 16*8);
  if (rc) goto update_end;
  
  /* copy the sign checksum to the outgoing pointer */
  MDget(&MD, mac, maclen);

update_end:
  memset(buf, 0, HASHKEYLEN);
  memset(K1, 0, HASHKEYLEN);
  memset(K2, 0, HASHKEYLEN);
  memset(extendedAuthKey, 0, HASHKEYLEN);
  memset(&MD, 0, sizeof(MD));

  if (newdata)
      free(newdata);
  return rc;
}

void
MDget(MDstruct *MD, u_char *buf, size_t buflen)
{
  int i, j;
  
  /* copy the checksum to the outgoing data (all of it that is requested). */
  for(i=0; i < 4 && i*4 < (int)buflen; i++)
    for(j=0; j < 4 && i*4+j < (int)buflen; j++)
      buf[i*4+j] = (MD->buffer[i] >> j*8) & 0xff;
}

/* 
** End of md5.c
****************************(cut)*****************************************/
