PE文件的两种状态

如下图，当PE文件于硬盘中存放时按照FileAlignment对齐，在内存中时按照SectionAlignment对齐，整个头可视为一体，在节表的最后和每个节区的最后按照格式对齐。

PE文件的拉伸与压缩

拉伸时将每个节区的PointerToRawData写入到VirtualAddress，反之亦然，头部直接按照SizeOfHeaders写入就行了

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LPVOID file2Image(LPVOID lpFileBuffer, DWORD *pdwBufferSize) {
  PIMAGE_DOS_HEADER pDos =
    (PIMAGE_DOS_HEADER)lpFileBuffer;
  PIMAGE_NT_HEADERS pNT =
    (PIMAGE_NT_HEADERS)((DWORD)lpFileBuffer + pDos->e_lfanew);
  PIMAGE_FILE_HEADER pFile =
    (PIMAGE_FILE_HEADER)((DWORD)pNT + 4);
  PIMAGE_OPTIONAL_HEADER pOption =
    (PIMAGE_OPTIONAL_HEADER)((DWORD)pFile + IMAGE_SIZEOF_FILE_HEADER);
  PIMAGE_SECTION_HEADER pFirstSection =
    PIMAGE_SECTION_HEADER((DWORD)pOption + pFile->SizeOfOptionalHeader);

  /*按照拉伸后的大小申请内存*/
  LPVOID lpImageBuffer = malloc(pOption->SizeOfImage);

  memset(lpImageBuffer, 0, pOption->SizeOfImage);

  /*写入头部，不需要对齐，下面从VA开始写入*/
  memcpy(lpImageBuffer, lpFileBuffer, pOption->SizeOfHeaders);

  /*遍历写入节区，按照内存对齐写入*/
  PIMAGE_SECTION_HEADER pSectionHeader = pFirstSection;
  for (int i = 0; i < pFile->NumberOfSections; i++) {
    memcpy(
      (LPVOID)((DWORD)lpImageBuffer + pSectionHeader->VirtualAddress),
      (LPVOID)((DWORD)lpFileBuffer + pSectionHeader->PointerToRawData),
      pSectionHeader->Misc.VirtualSize
    );
    /*指向下一个节表*/
    pSectionHeader = (PIMAGE_SECTION_HEADER)((DWORD)pSectionHeader + IMAGE_SIZEOF_SECTION_HEADER);
  }

  *pdwBufferSize = pOption->SizeOfImage;


  return lpImageBuffer;
}

LPVOID image2File(LPVOID lpImageBuffer, DWORD *pdwBufferSize) {
  PIMAGE_DOS_HEADER pDos =
    (PIMAGE_DOS_HEADER)lpImageBuffer;
  PIMAGE_NT_HEADERS pNT =
    (PIMAGE_NT_HEADERS)((DWORD)lpImageBuffer + pDos->e_lfanew);
  PIMAGE_FILE_HEADER pFile =
    (PIMAGE_FILE_HEADER)((DWORD)pNT + 4);
  PIMAGE_OPTIONAL_HEADER pOption =
    (PIMAGE_OPTIONAL_HEADER)((DWORD)pFile + IMAGE_SIZEOF_FILE_HEADER);
  PIMAGE_SECTION_HEADER pFirstSection =
    PIMAGE_SECTION_HEADER((DWORD)pOption + pFile->SizeOfOptionalHeader);

  /*获取最后一个节表的地址*/
  PIMAGE_SECTION_HEADER pLastSection =
    PIMAGE_SECTION_HEADER((DWORD)pFirstSection + ((pFile->NumberOfSections - 1) * IMAGE_SIZEOF_SECTION_HEADER));

  /*获取FileBuffer的大小，用最后一个节的文件偏移加上文件对齐大小得出*/
  *pdwBufferSize = pLastSection->PointerToRawData + pLastSection->SizeOfRawData;

  /*按照文件对齐大小分配内存*/
  LPVOID lpFileBuffer = malloc(*pdwBufferSize);

  memset(lpFileBuffer, 0, *pdwBufferSize);

  /*写入头，按照文件对齐*/
  memcpy(lpFileBuffer, lpImageBuffer, pOption->SizeOfHeaders);

  PIMAGE_SECTION_HEADER pSectionHeader = pFirstSection;
  for (int i = 0; i < pFile->NumberOfSections; i++) {
    /*按照文件对齐遍历写入*/
    memcpy(
      (LPVOID)((DWORD)lpFileBuffer + pSectionHeader->PointerToRawData),
      (LPVOID)((DWORD)lpImageBuffer + pSectionHeader->VirtualAddress),
      pSectionHeader->SizeOfRawData
    );

    /*指向下一个节表*/
    pSectionHeader=(PIMAGE_SECTION_HEADER)((DWORD)pSectionHeader + IMAGE_SIZEOF_SECTION_HEADER);
  }

  return lpFileBuffer;
}

遍历目录项

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#include<Windows.h>
#include<stdio.h>
#include<stdlib.h>
#include<PETool.h>
#pragma comment(lib,"PETool.lib")
#define FILEPATH TEXT("D:\\absolution\\temporary\\test.exe")
#define OUTFILEPATH TEXT("D:\\absolution\\temporary\\output.exe")

int main() {
  /*读取PE文件*/
  LPVOID lpFileBuffer = createFileBuffer(FILEPATH);

  if (!lpFileBuffer) {
    return 0;
  }

  DWORD dwSize;
  LPVOID lpImageBuffer = file2Image(lpFileBuffer, &dwSize);


  PIMAGE_DOS_HEADER pDos =
    (PIMAGE_DOS_HEADER)lpImageBuffer;
  PIMAGE_NT_HEADERS pNT =
    (PIMAGE_NT_HEADERS)((DWORD)lpImageBuffer + pDos->e_lfanew);
  PIMAGE_FILE_HEADER pFile =
    (PIMAGE_FILE_HEADER)((DWORD)pNT + 4);
  PIMAGE_OPTIONAL_HEADER pOption =
    (PIMAGE_OPTIONAL_HEADER)((DWORD)pFile + IMAGE_SIZEOF_FILE_HEADER);
  PIMAGE_SECTION_HEADER pFirstSection =
    (PIMAGE_SECTION_HEADER)((DWORD)pOption + pFile->SizeOfOptionalHeader);

  for (int i = 0; i < pOption->NumberOfRvaAndSizes; i++) {
    IMAGE_DATA_DIRECTORY IDD = pOption->DataDirectory[i];
    printf("表项%d \n%X\n%X\n---------\n", i, IDD.VirtualAddress, IDD.Size);
  }

  free(lpImageBuffer);

  free(lpFileBuffer);

  getchar();
}