1db822d866
Add new file type for Win32-PE executables (Dispack). Reset file type flag after filter processing for better compression. Fix array index handling for file type list.
151 lines
4.1 KiB
C++
151 lines
4.1 KiB
C++
/*
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* This file is a part of Pcompress, a chunked parallel multi-
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* algorithm lossless compression and decompression program.
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*
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* Copyright (C) 2014 Moinak Ghosh. All rights reserved.
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* Use is subject to license terms.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 3 of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this program.
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* If not, see <http://www.gnu.org/licenses/>.
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*
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* moinakg@belenix.org, http://moinakg.wordpress.com/
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*
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*/
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#include <sys/types.h>
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#include <unistd.h>
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#include <string.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <errno.h>
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#include "utils.h"
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#include "winsupport.h"
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#include "types.hpp"
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#include "dis.hpp"
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef unsigned char uchar_t;
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#pragma pack(1)
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struct FileHeader
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{
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sU32 SizeBefore; // number of bytes before start of code section
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sU32 SizeAfter; // number of bytes after code section
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sU32 SizeTransformed; // size of transformed code section
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sU32 SizeOriginal; // size of untransformed code section
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sU32 Origin; // virtual address of first byte
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};
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#pragma pack()
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size_t
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dispack_filter_encode(uchar_t *inData, size_t len, uchar_t **out_buf)
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{
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uchar_t *pos;
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FileHeader hdr;
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*out_buf = (uchar_t *)malloc(len);
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if (*out_buf == NULL)
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return (0);
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// assume the input file is a PE executable.
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IMAGE_DOS_HEADER *doshdr = (IMAGE_DOS_HEADER *) inData;
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IMAGE_NT_HEADERS *nthdr = (IMAGE_NT_HEADERS *) (inData + doshdr->e_lfanew);
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if (nthdr->FileHeader.Machine != IMAGE_FILE_MACHINE_I386 ||
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nthdr->OptionalHeader.Magic != IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
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// Only 32-bit PE files for x86 supported
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return (0);
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}
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sU32 imageBase = nthdr->OptionalHeader.ImageBase;
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sU32 codeStart = nthdr->OptionalHeader.BaseOfCode;
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sU32 codeSize = nthdr->OptionalHeader.SizeOfCode;
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sU32 fileOffs = 0; // find file offset of first section
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// find section containing code
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IMAGE_SECTION_HEADER *sec = IMAGE_FIRST_SECTION(nthdr);
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for (sInt i=0;i<nthdr->FileHeader.NumberOfSections;i++) {
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if (codeStart >= sec[i].VirtualAddress && codeStart <
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sec[i].VirtualAddress + sec[i].SizeOfRawData)
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fileOffs = sec[i].PointerToRawData + (codeStart - sec[i].VirtualAddress);
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}
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if (fileOffs == 0) {
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// Code section not found!
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return (0);
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}
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// Keep space for header
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pos = *out_buf + sizeof (hdr);
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// transform code
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sU32 transSize = len - sizeof (hdr);
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if (DisFilter(inData + fileOffs, codeSize, imageBase + codeStart, pos, transSize) == NULL)
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return (0);
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pos += transSize;
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// Now plonk the header
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hdr.SizeBefore = fileOffs;
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hdr.SizeAfter = len - (fileOffs + codeSize);
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hdr.SizeTransformed = transSize;
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hdr.SizeOriginal = codeSize;
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hdr.Origin = imageBase + codeStart;
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memcpy(*out_buf, &hdr, sizeof (hdr));
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// Copy rest of the data
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memcpy(pos, inData, hdr.SizeBefore);
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pos += hdr.SizeBefore;
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memcpy(pos, inData + (fileOffs + codeSize), hdr.SizeAfter);
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pos += hdr.SizeAfter;
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return (pos - *out_buf);
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}
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size_t
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dispack_filter_decode(uchar_t *inData, size_t len, uchar_t **out_buf)
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{
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uchar_t *decoded;
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FileHeader *hdr = (FileHeader *)inData;
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sU8 *transformed = inData + sizeof (FileHeader);
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sU8 *before = transformed + hdr->SizeTransformed;
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sU8 *after = before + hdr->SizeBefore;
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// alloc buffer for unfiltered code
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*out_buf = (uchar_t *)malloc(len);
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if (*out_buf == NULL)
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return (0);
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decoded = *out_buf;
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memcpy(decoded, before, hdr->SizeBefore);
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decoded += hdr->SizeBefore;
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if (!DisUnFilter(transformed, hdr->SizeTransformed, decoded,
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hdr->SizeOriginal, hdr->Origin)) {
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return (0);
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}
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decoded += hdr->SizeOriginal;
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memcpy(decoded, after, hdr->SizeAfter);
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decoded += hdr->SizeAfter;
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return (decoded - *out_buf);
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}
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#ifdef __cplusplus
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}
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#endif
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