xref: /AOO41X/main/tools/bootstrp/md5.cxx (revision cdf0e10c4e3984b49a9502b011690b615761d4a3)

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// MARKER(update_precomp.py): autogen include statement, do not remove
#include "precompiled_tools.hxx"

#include "md5.hxx"

#include <cstddef>
#include <stdio.h>

#include <tools/string.hxx>

#ifdef WNT
#define FILE_OPEN_READ	"rb"
#else
#define FILE_OPEN_READ	"r"
#endif

// Extended calc_md5_checksum to recognize Windows executables and libraries. To
// create the same md5 checksum for a (code/data) identical file it ignores a different
// date and header checksum. Please see crashrep/source/win32/soreport.cpp
// where the same method is also used. The crash reporter uses the MD5
// checksums to transfer them to the crash database. You have to make sure that both
// methods use the same algorithm otherwise there could be problems with stack reports.

void normalize_pe_image(sal_uInt8* buffer, size_t nBufferSize)
{
	const int OFFSET_PE_OFFSET = 0x3c;
	const int OFFSET_COFF_TIMEDATESTAMP = 4;
	const int PE_SIGNATURE_SIZE = 4;
	const int COFFHEADER_SIZE = 20;
	const int OFFSET_PE_OPTIONALHEADER_CHECKSUM = 64;

	// Check the header part of the file buffer
	if (buffer[0] == sal_uInt8('M') && buffer[1] == sal_uInt8('Z'))
	{
		unsigned long PEHeaderOffset = (long)buffer[OFFSET_PE_OFFSET];
		if (PEHeaderOffset < nBufferSize-4)
		{
			if ( buffer[PEHeaderOffset+0] == sal_uInt8('P') &&
				 buffer[PEHeaderOffset+1] == sal_uInt8('E') &&
				 buffer[PEHeaderOffset+2] == 0 &&
				 buffer[PEHeaderOffset+3] == 0 )
			{
				PEHeaderOffset += PE_SIGNATURE_SIZE;
				if (PEHeaderOffset+OFFSET_COFF_TIMEDATESTAMP < nBufferSize-4)
				{
					// Set timedatestamp and checksum fields to a normalized
					// value to enforce the same MD5 checksum for identical
					// Windows	executables/libraries.
					buffer[PEHeaderOffset+OFFSET_COFF_TIMEDATESTAMP+0] = 0;
					buffer[PEHeaderOffset+OFFSET_COFF_TIMEDATESTAMP+1] = 0;
					buffer[PEHeaderOffset+OFFSET_COFF_TIMEDATESTAMP+2] = 0;
					buffer[PEHeaderOffset+OFFSET_COFF_TIMEDATESTAMP+3] = 0;
				}

				if (PEHeaderOffset+COFFHEADER_SIZE+OFFSET_PE_OPTIONALHEADER_CHECKSUM < nBufferSize-4)
				{
					// Set checksum to a normalized value
					buffer[PEHeaderOffset+COFFHEADER_SIZE+OFFSET_PE_OPTIONALHEADER_CHECKSUM] = 0;
					buffer[PEHeaderOffset+COFFHEADER_SIZE+OFFSET_PE_OPTIONALHEADER_CHECKSUM+1] = 0;
					buffer[PEHeaderOffset+COFFHEADER_SIZE+OFFSET_PE_OPTIONALHEADER_CHECKSUM+2] = 0;
					buffer[PEHeaderOffset+COFFHEADER_SIZE+OFFSET_PE_OPTIONALHEADER_CHECKSUM+3] = 0;
				}
			}
		}
	}
}

rtlDigestError calc_md5_checksum( const char *filename, ByteString &aChecksum )
{
    const size_t BUFFER_SIZE  = 0x1000;
	const size_t MINIMAL_SIZE = 512;

	sal_uInt8 checksum[RTL_DIGEST_LENGTH_MD5];
	rtlDigestError	error = rtl_Digest_E_None;

	FILE *fp = fopen( filename, FILE_OPEN_READ );

	if ( fp )
	{
		rtlDigest digest = rtl_digest_createMD5();

		if ( digest )
		{
			size_t			nBytesRead;
			sal_uInt8		buffer[BUFFER_SIZE];
			bool			bHeader(true);

			while ( rtl_Digest_E_None == error &&
				0 != (nBytesRead = fread( buffer, 1, sizeof(buffer), fp )) )
			{
				if (bHeader)
				{
					bHeader = false;
					if (nBytesRead >= MINIMAL_SIZE && buffer[0] == sal_uInt8('M') && buffer[1] == sal_uInt8('Z') )
						normalize_pe_image(buffer, nBytesRead);
				}

				error = rtl_digest_updateMD5( digest, buffer, nBytesRead );
			}

			if ( rtl_Digest_E_None == error )
			{
				error = rtl_digest_getMD5( digest, checksum, sizeof(checksum) );
			}

			rtl_digest_destroyMD5( digest );

            for ( std::size_t i = 0; i < sizeof(checksum); i++ )
            {
                if ( checksum[i] < 16 )
                    aChecksum.Append( "0" );
                aChecksum += ByteString::CreateFromInt32( checksum[i], 16 );
            }
		}

		fclose( fp );
	}
	else
		error = rtl_Digest_E_Unknown;

	return error;
}