Add Imports to PE File

unit uAddImport;

//steve10120

interface

uses Windows;

type

  TFuncArray = array of string;

  TImports = packed record

    szLibName:  string;

    Funcs:      TFuncArray;

  end;

procedure AddImport(szFilePath:string; Imports:TImports);

type

  PImageImportDescriptor = ^TImageImportDescriptor;

  TImageImportDescriptor = packed record

    OriginalFirstThunk: DWORD;

    TimeDateStamp: DWORD;

    ForwarderChain: DWORD;

    Name: DWORD;

    FirstThunk: DWORD;

  end;

type

  PImportByName = ^TImportByName;

  TImportByName = packed record

    Name1:        DWORD;

  end;

type

  TByteArray = array of Byte;

implementation

function FileToBytes(sPath:string; var bFile:TByteArray):Boolean;

var

hFile:    THandle;

dSize:    DWORD;

dRead:    DWORD;

begin

  Result := FALSE;

  hFile := CreateFile(PChar(sPath), GENERIC_READ, FILE_SHARE_READ, nil, OPEN_EXISTING, 0, 0);

  if hFile <> 0 then

  begin

    dSize := GetFileSize(hFile, nil);

    SetFilePointer(hFile, 0, nil, FILE_BEGIN);

    SetLength(bFile, dSize);

    if ReadFile(hFile, bFile[0], dSize, dRead, nil) then

      Result := TRUE;

    CloseHandle(hFile);

  end;

end;

procedure BytesToFile(bData:TByteArray; sPath:string);

var

hFile:    THandle;

dWritten: DWORD;

begin

  hFile := CreateFile(PChar(sPath), GENERIC_WRITE, FILE_SHARE_WRITE, nil, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);

  if hFile <> 0 then

  begin

    SetFilePointer(hFile, 0, nil, FILE_BEGIN);

    WriteFile(hFile, bData[0],Length(bData), dWritten, nil);

    CloseHandle(hFile);

  end;

end;

function OffsetToRVA(dwOffset:DWORD; dwVA:DWORD; dwRaw:DWORD):DWORD;

begin

  Result := dwOffset - dwRaw + dwVA;

end;

function RVAToOffset(dwRVA:DWORD; dwVA:DWORD; dwRaw:DWORD):DWORD;

begin

  Result := dwRVA - dwVA + dwRaw;

end;

function Align(dwValue:DWORD; dwAlign:DWORD):DWORD;

begin

  if dwAlign <> 0 then

  begin

    if dwValue mod dwAlign <> 0 then

    begin

      Result := (dwValue + dwAlign) - (dwValue mod dwAlign);

      Exit;

    end;

  end;

  Result := dwValue;

end;

procedure AddImport(szFilePath:string; Imports:TImports);

var

  bFile:    TByteArray;

  IDH:      PImageDosHeader;

  INH:      PImageNtHeaders;

  ISH:      PImageSectionHeader;

  IID:      PImageImportDescriptor;

  IBN:      array of TImportByName;

  i:        DWORD;

  dwIATPos: DWORD;

  dwPos:    DWORD;

  bBuff:    TByteArray;

  dwSize:   DWORD;

begin

  if FileToBytes(szFilePath, bFile) then

  begin

    IDH := @bFile[0];

    if IDH.e_magic = IMAGE_DOS_SIGNATURE then

    begin

      INH := @bFile[IDH._lfanew];

      if INH.Signature = IMAGE_NT_SIGNATURE then

      begin

        for i := 0 to INH.FileHeader.NumberOfSections - 1 do

        begin

          ISH := @bFile[IDH._lfanew + 248 + i * 40];

          if (INH.OptionalHeader.DataDirectory[1].VirtualAddress >= ISH.VirtualAddress) and (INH.OptionalHeader.DataDirectory[1].VirtualAddress <= (ISH.VirtualAddress + ISH.Misc.VirtualSize)) then

          begin

            dwIATPos := RVAToOffset(INH.OptionalHeader.DataDirectory[1].VirtualAddress, ISH.VirtualAddress, ISH.PointerToRawData);

            Break;

          end;

        end;

        IID := @bFile[dwIATPos];

        SetLength(bBuff, 20);

        dwPos := 0;

        repeat

          CopyMemory(@bBuff[dwPos], IID, 20);

          Inc(IID);

          Inc(dwPos, 20);

          SetLength(bBuff, dwPos + 20);

        until IID.Name = 0;

        dwPos := Length(bFile);

        dwSize := Align(Length(bBuff) + 20, INH.OptionalHeader.FileAlignment);

        SetLength(bFile, Length(bFile) + dwSize);

        ISH := @bFile[IDH._lfanew + 248 + (INH.FileHeader.NumberOfSections - 1) * 40];

        Imports.szLibName := Imports.szLibName + #0;

        CopyMemory(@bFile[dwPos], @Imports.szLibName[1], Length(Imports.szLibName));

        IID.Name := OffsetToRVA(dwPos, ISH.VirtualAddress, ISH.PointerToRawData);

        Inc(dwPos, Length(Imports.szLibName));

        SetLength(IBN, Length(Imports.Funcs));

        for i := 0 to Length(Imports.Funcs) - 1 do

        begin

          Imports.Funcs[i] := #0#0 + Imports.Funcs[i] + #0;

          CopyMemory(@bFile[dwPos], @Imports.Funcs[i][1], Length(Imports.Funcs[i]));

          IBN[i].Name1 := OffsetToRVA(dwPos, ISH.VirtualAddress, ISH.PointerToRawData);

          Inc(dwPos, Length(Imports.Funcs[i]));

        end;

        IID.FirstThunk := OffsetToRVA(dwPos + Length(bBuff) + 20, ISH.VirtualAddress, ISH.PointerToRawData);

        CopyMemory(@bBuff[Length(bBuff) - 20], IID, 20);

        SetLength(bBuff, Length(bBuff) + 20);

        CopyMemory(@bFile[dwPos], @bBuff[0], Length(bBuff));

        INH.OptionalHeader.DataDirectory[1].VirtualAddress := OffsetToRVA(dwPos, ISH.VirtualAddress, ISH.PointerToRawData);

        INH.OptionalHeader.DataDirectory[1].Size := Length(bBuff);

        Inc(dwPos, Length(bBuff));

        for i := 0 to Length(IBN) - 1 do

        begin

          CopyMemory(@bFile[dwPos], @IBN[i], 4);

          Inc(dwPos, 4);

        end;

        Inc(ISH.SizeOfRawData, dwSize);

        Inc(ISH.Misc.VirtualSize, dwSize);

        CopyMemory(@bFile[IDH._lfanew + 248 + (INH.FileHeader.NumberOfSections - 1) * 40], ISH, 40);

        INH.OptionalHeader.SizeOfImage := ISH.VirtualAddress + ISH.Misc.VirtualSize;

        CopyMemory(@bFile[IDH._lfanew], INH, 248);

        BytesToFile(bFile, szFilePath);

      end;

    end;

  end;

end;

end.

var

  Imports:  TImports;

begin

  SetLength(Imports.Funcs, 2);

  Imports.szLibName := 'urlmon.dll';

  Imports.Funcs[0] := 'URLDownloadToFileA';

  Imports.Funcs[1] := 'URLDownloadToFileW';

  AddImport('Hello.exe', Imports);

end.