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/*
* farm9crypt.cc
*
* Copyright (C) 2000-2003 farm9.com, Inc. All Rights Reserved.
*
* C interface between netcat and twofish.
*
* Intended for direct replacement of system "read" and "write" calls.
*
* Design is like a "C" version of an object.
*
* Static variables, initialized with farm9crypt_init creates a
* "readDecryptor" and "writeEncryptor" object, both of which are based
* on the assumption that text lines are being transferred between
* the two sides.
*
* jojo@farm9.com -- 29 Sept 2000, fixed buffer size (really it should have crashed!)
* jojo@farm9.com -- 2 Oct 2000, yet another bug fix...(thanks to Jimmy for reporting this!)
* jojo@farm9.com -- 2 Oct 2000, no more printf of key cuz its stupid (yet another Dragos suggestion)
* jeff@wwti.com -- 9 Feb 2001, added string.h include for yet more linux brokenness
* jsilva@farm9.com -- 2 December 2003, relicensed under GPL.
*/
/***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
***************************************************************************/
#ifndef WIN32
#include <string.h>
#include <sys/types.h> // suggested by several people -- for OpenBSD, FreeBSD compiles
#include <sys/socket.h> /* basics, SO_ and AF_ defs, sockaddr, ... */
#include <stdlib.h>
#else
#include <fcntl.h>
#include <io.h>
#include <conio.h>
#include <winsock.h>
#include <time.h>
#endif
extern "C"
{
#include "farm9crypt.h"
}
#include "twofish2.h"
static int debug = false;
static int initialized = false;
static TwoFish* decryptor = NULL;
static TwoFish* encryptor = NULL;
extern "C" void farm9crypt_debug() {
debug = true;
}
/*
* farm9crypt_initialized
*
* Return Value:
* true if this module has been initialized, otherwise false
*/
extern "C" int farm9crypt_initialized() {
return( initialized );
}
/*
* farm9crypt_init
*
* Input Parameters:
* keystr -- used to generate Twofish key for encryption and decryption
*
* Return Value:
* none
*/
extern "C" void farm9crypt_init( char* keystr ) {
// printf( "farm9crypt_init: %s\n", keystr );
encryptor = new TwoFish( generateKey( keystr ), false, NULL, NULL );
decryptor = new TwoFish( generateKey( keystr ), true, NULL, NULL );
initialized = true;
srand( 1000 );
}
/*
* farm9crypt_read
*
* Susbstitute for socket read (one line replacement in netcat)
*
* Handles decryption
*
* Parameters same as "recv"
*/
static char outBuffer[8193];
static char inBuffer[8193];
extern "C" int farm9crypt_read( int sockfd, char* buf, int size ) {
int total = 0;
char outbuf[16];
char outbuf2[16];
if ( size > 8192 ) {
size = 8192;
}
while (total < 32) {
int result = recv( sockfd, buf + total, 32 - total, 0 );
if ( result > 0 ) {
total += result;
} else {
return(0);
}
}
decryptor->resetCBC();
decryptor->setOutputBuffer( (unsigned char*)&outBuffer[0] );
decryptor->blockCrypt( buf, outbuf, 16 );
decryptor->flush();
decryptor->setOutputBuffer( (unsigned char*)&outBuffer[0] );
decryptor->blockCrypt( buf + 16, outbuf2, 16 );
int limit = atoi( outbuf );
total = 0;
char* inbuf = &inBuffer[0];
while ( total < limit ) {
int result = recv( sockfd, inbuf + total, limit - total, 0 );
if ( result > 0 ) {
total += result;
} else {
break;
}
}
int loc = 0;
char* obuf = &outBuffer[0];
while ( total > 0 ) {
int amount = 16;
if ( total < amount ) {
amount = total;
}
decryptor->blockCrypt( inbuf + loc, outbuf, amount );
total -= amount;
loc += 16;
}
decryptor->flush();
memcpy( buf, obuf + 32, limit );
*(buf + limit) = 0; // in case
return( limit );
}
static char localBuf[2000];
extern "C" int farm9crypt_write( int sockfd, char* buf, int size ) {
char tempbuf[16];
char outbuf[16];
sprintf( tempbuf, "%d %d", size, rand() );
tempbuf[strlen(tempbuf)] = 'x';
encryptor->setSocket( sockfd );
encryptor->setOutputBuffer( (unsigned char*)&outBuffer[0] );
encryptor->resetCBC();
encryptor->blockCrypt( tempbuf, outbuf, 16 );
encryptor->blockCrypt( tempbuf, outbuf, 16 );
int loc = 0;
int totalsize = size;
while ( size > 0 ) {
int amount = 16;
if ( size < amount ) {
amount = size;
}
encryptor->blockCrypt( buf + loc, &outBuffer[loc+32], amount );
size -= amount;
loc += amount;
}
encryptor->flush();
return( totalsize );
}
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