type //定义一个跳转的结构 TImportCode = packed record JumpInstruction: Word; //定义跳转指令jmp AddressOfPointerToFunction: ^Pointer; //定义要跳转到的函数 end; PImportCode = ^TImportCode; implementation
function LocateFunctionAddress(Code: Pointer): Pointer; var func: PImportCode; begin Result := Code; if Code = nil then exit; try func := code; if (func.JumpInstruction = $25FF) then begin Result := func.AddressOfPointerToFunction^; end; except Result := nil; end; end;
function RepointFunction(OldFunc, NewFunc: Pointer): Integer; var IsDone: TList; function RepointAddrInModule(hModule: THandle; OldFunc, NewFunc: Pointer): Integer; var Dos: PImageDosHeader; NT: PImageNTHeaders; ImportDesc: PImage_Import_Entry; RVA: DWORD; Func: ^Pointer; DLL: string; f: Pointer; written: DWORD; begin Result := 0; Dos := Pointer(hModule); if IsDone.IndexOf(Dos) >= 0 then exit; IsDone.Add(Dos);
OldFunc := LocateFunctionAddress(OldFunc);
if IsBadReadPtr(Dos, SizeOf(TImageDosHeader)) then exit; if Dos.e_magic <> IMAGE_DOS_SIGNATURE then exit; NT := Pointer(Integer(Dos) + dos._lfanew);
if RVA = 0 then exit; ImportDesc := pointer(integer(Dos) + RVA); while (ImportDesc^.Name <> 0) do begin DLL := PChar(Integer(Dos) + ImportDesc^.Name); RepointAddrInModule(GetModuleHandle(PChar(DLL)), OldFunc, NewFunc); Func := Pointer(Integer(DOS) + ImportDesc.LookupTable); while Func^ <> nil do begin f := LocateFunctionAddress(Func^); if f = OldFunc then begin WriteProcessMemory(GetCurrentProcess, Func, @NewFunc, 4, written); if Written > 0 then Inc(Result); end; Inc(Func); end; Inc(ImportDesc); end; end;
begin IsDone := TList.Create; try Result := RepointAddrInModule(GetModuleHandle(nil), OldFunc, NewFunc); finally IsDone.Free; end; end;