/*

** 2017-10-13

**

** The author disclaims copyright to this source code.  In place of

** a legal notice, here is a blessing:

**

**    May you do good and not evil.

**    May you find forgiveness for yourself and forgive others.

**    May you share freely, never taking more than you give.

**

*************************************************************************

**

** This file contains code to implement an MD5 extension to TCL.

*/

#include "sqlite3.h"

#include <stdlib.h>

#include <string.h>

#include "sqlite3.h"

#if defined(INCLUDE_SQLITE_TCL_H)

# include "sqlite_tcl.h"

#else

# include "tcl.h"

# ifndef SQLITE_TCLAPI

#  define SQLITE_TCLAPI

# endif

#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.

 */

/*

 * If compiled on a machine that doesn't have a 32-bit integer,

 * you just set "uint32" to the appropriate datatype for an

 * unsigned 32-bit integer.  For example:

 *

 *       cc -Duint32='unsigned long' md5.c

 *

 */

#ifndef uint32

#  define uint32 unsigned int

#endif

struct MD5Context {

  int isInit;

  uint32 buf[4];

  uint32 bits[2];

  unsigned char in[64];

};

typedef struct MD5Context MD5Context;

/*

 * Note: this code is harmless on little-endian machines.

 */

static void byteReverse (unsigned char *buf, unsigned longs){

        uint32 t;

        do {

                t = (uint32)((unsigned)buf[3]<<8 | buf[2]) << 16 |

                            ((unsigned)buf[1]<<8 | buf[0]);

                *(uint32 *)buf = t;

                buf += 4;

        } while (--longs);

}

/* 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(uint32 buf[4], const uint32 in[16]){

        register uint32 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;

}

/*

 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious

 * initialization constants.

 */

static void MD5Init(MD5Context *ctx){

        ctx->isInit = 1;

        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.

 */

static

void MD5Update(MD5Context *ctx, const unsigned char *buf, unsigned int len){

        uint32 t;

        /* Update bitcount */

        t = ctx->bits[0];

        if ((ctx->bits[0] = t + ((uint32)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) {

                        memcpy(p, buf, len);

                        return;

                }

                memcpy(p, buf, t);

                byteReverse(ctx->in, 16);

                MD5Transform(ctx->buf, (uint32 *)ctx->in);

                buf += t;

                len -= t;

        }

        /* Process data in 64-byte chunks */

        while (len >= 64) {

                memcpy(ctx->in, buf, 64);

                byteReverse(ctx->in, 16);

                MD5Transform(ctx->buf, (uint32 *)ctx->in);

                buf += 64;

                len -= 64;

        }

        /* Handle any remaining bytes of data. */

        memcpy(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)

 */

static void MD5Final(unsigned char digest[16], MD5Context *ctx){

        unsigned 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, (uint32 *)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 */

        memcpy(ctx->in + 14*4, ctx->bits, 8);

        MD5Transform(ctx->buf, (uint32 *)ctx->in);

        byteReverse((unsigned char *)ctx->buf, 4);

        memcpy(digest, ctx->buf, 16);

}

/*

** Convert a 128-bit MD5 digest into a 32-digit base-16 number.

*/

static void MD5DigestToBase16(unsigned char *digest, char *zBuf){

  static char const zEncode[] = "0123456789abcdef";

  int i, j;

  for(j=i=0; i<16; i++){

    int a = digest[i];

    zBuf[j++] = zEncode[(a>>4)&0xf];

    zBuf[j++] = zEncode[a & 0xf];

  }

  zBuf[j] = 0;

}

/*

** Convert a 128-bit MD5 digest into sequency of eight 5-digit integers

** each representing 16 bits of the digest and separated from each

** other by a "-" character.

*/

static void MD5DigestToBase10x8(unsigned char digest[16], char zDigest[50]){

  int i, j;

  unsigned int x;

  for(i=j=0; i<16; i+=2){

    x = digest[i]*256 + digest[i+1];

    if( i>0 ) zDigest[j++] = '-';

    sqlite3_snprintf(50-j, &zDigest[j], "%05u", x);

    j += 5;

  }

  zDigest[j] = 0;

}

/*

** A TCL command for md5.  The argument is the text to be hashed.  The

** Result is the hash in base64.

*/

static int SQLITE_TCLAPI md5_cmd(

  void*cd,

  Tcl_Interp *interp,

  int argc,

  const char **argv

){

  MD5Context ctx;

  unsigned char digest[16];

  char zBuf[50];

  void (*converter)(unsigned char*, char*);

  if( argc!=2 ){

    Tcl_AppendResult(interp,"wrong # args: should be \"", argv[0],

        " TEXT\"", (char*)0);

    return TCL_ERROR;

  }

  MD5Init(&ctx;;

  MD5Update(&ctx, (unsigned char*)argv[1], (unsigned)strlen(argv[1]));

  MD5Final(digest, &ctx;;

  converter = (void(*)(unsigned char*,char*))cd;

  converter(digest, zBuf);

  Tcl_AppendResult(interp, zBuf, (char*)0);

  return TCL_OK;

}

/*

** A TCL command to take the md5 hash of a file.  The argument is the

** name of the file.

*/

static int SQLITE_TCLAPI md5file_cmd(

  void*cd,

  Tcl_Interp *interp,

  int argc,

  const char **argv

){

  FILE *in;

  int ofst;

  int amt;

  MD5Context ctx;

  void (*converter)(unsigned char*, char*);

  unsigned char digest[16];

  char zBuf[10240];

  if( argc!=2 && argc!=4 ){

    Tcl_AppendResult(interp,"wrong # args: should be \"", argv[0],

        " FILENAME [OFFSET AMT]\"", (char*)0);

    return TCL_ERROR;

  }

  if( argc==4 ){

    ofst = atoi(argv[2]);

    amt = atoi(argv[3]);

  }else{

    ofst = 0;

    amt = 2147483647;

  }

  in = fopen(argv[1],"rb");

  if( in==0 ){

    Tcl_AppendResult(interp,"unable to open file \"", argv[1],

         "\" for reading", (char*)0);

    return TCL_ERROR;

  }

  fseek(in, ofst, SEEK_SET);

  MD5Init(&ctx;;

  while( amt>0 ){

    int n;

    n = (int)fread(zBuf, 1, sizeof(zBuf)<=amt ? sizeof(zBuf) : amt, in);

    if( n<=0 ) break;

    MD5Update(&ctx, (unsigned char*)zBuf, (unsigned)n);

    amt -= n;

  }

  fclose(in);

  MD5Final(digest, &ctx;;

  converter = (void(*)(unsigned char*,char*))cd;

  converter(digest, zBuf);

  Tcl_AppendResult(interp, zBuf, (char*)0);

  return TCL_OK;

}

/*

** Register the four new TCL commands for generating MD5 checksums

** with the TCL interpreter.

*/

int Md5_Init(Tcl_Interp *interp){

  Tcl_CreateCommand(interp, "md5", (Tcl_CmdProc*)md5_cmd,

                    MD5DigestToBase16, 0);

  Tcl_CreateCommand(interp, "md5-10x8", (Tcl_CmdProc*)md5_cmd,

                    MD5DigestToBase10x8, 0);

  Tcl_CreateCommand(interp, "md5file", (Tcl_CmdProc*)md5file_cmd,

                    MD5DigestToBase16, 0);

  Tcl_CreateCommand(interp, "md5file-10x8", (Tcl_CmdProc*)md5file_cmd,

                    MD5DigestToBase10x8, 0);

  return TCL_OK;

}

/*

** During testing, the special md5sum() aggregate function is available.

** inside SQLite.  The following routines implement that function.

*/

static void md5step(sqlite3_context *context, int argc, sqlite3_value **argv){

  MD5Context *p;

  int i;

  if( argc<1 ) return;

  p = sqlite3_aggregate_context(context, sizeof(*p));

  if( p==0 ) return;

  if( !p->isInit ){

    MD5Init(p);

  }

  for(i=0; i

    const char *zData = (char*)sqlite3_value_text(argv[i]);

    if( zData ){

      MD5Update(p, (unsigned char*)zData, (int)strlen(zData));

    }

  }

}

static void md5finalize(sqlite3_context *context){

  MD5Context *p;

  unsigned char digest[16];

  char zBuf[33];

  p = sqlite3_aggregate_context(context, sizeof(*p));

  MD5Final(digest,p);

  MD5DigestToBase16(digest, zBuf);

  sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);

}

int Md5_Register(

  sqlite3 *db,

  char **pzErrMsg,

  const sqlite3_api_routines *pThunk

){

  int rc = sqlite3_create_function(db, "md5sum", -1, SQLITE_UTF8, 0, 0,

                                 md5step, md5finalize);

  sqlite3_overload_function(db, "md5sum", -1);  /* To exercise this API */

  return rc;

}