/* * EWF CRC handling * * Copyright (c) 2006-2007, Joachim Metz <forensics@hoffmannbv.nl>, * Hoffmann Investigations. All rights reserved. * * Refer to AUTHORS for acknowledgements. * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * * - Redistributions of source code must retain the above copyright notice, *   this list of conditions and the following disclaimer. * - Redistributions in binary form must reproduce the above copyright notice, *   this list of conditions and the following disclaimer in the documentation *   and/or other materials provided with the distribution. * - Neither the name of the creator, related organisations, nor the names of *   its contributors may be used to endorse or promote products derived from *   this software without specific prior written permission. * - All advertising materials mentioning features or use of this software *   must acknowledge the contribution by people stated in the acknowledgements. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER, COMPANY AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */#include "libewf_includes.h"#if defined( HAVE_ZLIB_H ) && defined( HAVE_LIBZ )#include <zlib.h>#endif#include "libewf_common.h"#include "libewf_endian.h"#include "libewf_notify.h"#include "ewf_crc.h"/* Reads the CRC from a file descriptor * Returns the amount of bytes read if successful, or -1 on error */ssize_t ewf_crc_read( EWF_CRC *crc, int file_descriptor ){	uint8_t buffer[ 4 ];	ssize_t count = 0;	size_t size   = EWF_CRC_SIZE;	if( crc == NULL )	{		LIBEWF_WARNING_PRINT( "ewf_crc_read: invalid CRC.\n" );		return( -1 );	}	count = libewf_common_read( file_descriptor, buffer, size );	if( count < (ssize_t) size )	{		LIBEWF_WARNING_PRINT( "ewf_crc_read: unable to read CRC.\n" );		return( -1 );	}	if( libewf_endian_convert_32bit( crc, buffer ) != 1 )	{		LIBEWF_WARNING_PRINT( "ewf_crc_read: unable to convert CRC value.\n" );		return( -1 );	}	return( count );}/* Writes the CRC to a file descriptor * Returns the amount of bytes written, or -1 on error */ssize_t ewf_crc_write( EWF_CRC *crc, int file_descriptor ){	uint8_t buffer[ 4 ];	ssize_t count = 0;	size_t size   = EWF_CRC_SIZE;	if( crc == NULL )	{		LIBEWF_WARNING_PRINT( "ewf_crc_write: invalid CRC.\n" );		return( -1 );	}	if( libewf_endian_revert_32bit( *crc, buffer ) != 1 )	{		LIBEWF_WARNING_PRINT( "ewf_crc_write: unable to revert CRC value.\n" );		return( -1 );	}	count = libewf_common_write( file_descriptor, buffer, size );	if( count < (ssize_t) size )	{		LIBEWF_WARNING_PRINT( "ewf_crc_write: error writing CRC.\n" );		return( -1 );	}	return( count );}/* Calculates the EWF CRC * When calling this function to start a new CRC "previous_key" should be 1 * Returns 1 if calculation is successful, or -1 on error * * The original algorithm was taken from the ASR data web site */int8_t ewf_crc_calculate( EWF_CRC *crc, uint8_t *buffer, size_t size, uint32_t previous_key ){	if( crc == NULL )	{		LIBEWF_WARNING_PRINT( "ewf_crc_calculate: invalid CRC.\n" );		return( -1 );	}	if( buffer == NULL )	{		LIBEWF_WARNING_PRINT( "ewf_crc_calculate: invalid buffer.\n" );		return( -1 );	}	if( size > (size_t) SSIZE_MAX )	{		LIBEWF_WARNING_PRINT( "ewf_crc_calculate: invalid size value exceeds maximum.\n" );		return( -1 );	}	*crc = (EWF_CRC) adler32( (uLong) previous_key, (const Bytef *) buffer, (uInt) size );	return( 1 );}