[Frage] Inject DLL via CRT @ EntryPoint

//         ManualMap - by Darawk
//        Featured @ www.RealmGX.com & www.Darawk.com
//
//   The purpose of ManualMap is to "manually map" a dll
//   module into a remote process's address space.  This
//   means that instead of just manipulating the remote
//   process into calling the LoadLibrary function, we
//   have our own emulation of what LoadLibrary does
//   without all those annoying detectability issues ^^.
//   The advantage of this method over using something
//   like my CloakDll function, is that this method never
//   has to call a function like LoadLibrary inside the
//   remote process.  Since LoadLibrary can be hooked,
//   the dll   could still be caught at the injection stage.
//   Or possibly also through the weakness I discussed in
//   the comment header of that file, which is not present
//   when using this technique.
#include <windows.h>
#include <tlhelp32.h>
#include <shlwapi.h>

#pragma comment(lib, "shlwapi.lib")

#define IMAGE_DIRECTORY_ENTRY_IMPORT 1
#define IMAGE_DIRECTORY_ENTRY_BASERELOC 5

//   Pietrek's macro
//
//   MakePtr is a macro that allows you to easily add to values (including
//   pointers) together without dealing with C's pointer arithmetic.  It
//   essentially treats the last two parameters as DWORDs.  The first
//   parameter is used to typecast the result to the appropriate pointer type.
#define MakePtr( cast, ptr, addValue ) (cast)( (DWORD_PTR)(ptr) + (DWORD_PTR)(addValue))

//   This one is mine, but obviously..."adapted" from matt's original idea =p
#define MakeDelta(cast, x, y) (cast) ( (DWORD_PTR)(x) - (DWORD_PTR)(y))

bool MapRemoteModule(unsigned long, char *);

unsigned long GetProcessIdByName(char *);
HMODULE GetRemoteModuleHandle(unsigned long, char *);
FARPROC GetRemoteProcAddress(unsigned long, char *, char *);

bool FixImports(unsigned long, void *, IMAGE_NT_HEADERS *, IMAGE_IMPORT_DESCRIPTOR *);
bool FixRelocs(void *, void *, IMAGE_NT_HEADERS *, IMAGE_BASE_RELOCATION *, unsigned int);
bool MapSections(HANDLE, void *, void *, IMAGE_NT_HEADERS *);

PIMAGE_SECTION_HEADER GetEnclosingSectionHeader(DWORD, PIMAGE_NT_HEADERS);
LPVOID GetPtrFromRVA(DWORD, PIMAGE_NT_HEADERS, PBYTE);

//   Stub that calls the Dll from within the remote process.
//   This is necessary because a DllMain function takes 3
//   arguments, and CreateRemoteThread can pass only 1.
__declspec(naked) void DllCall_stub(HMODULE hMod)
{
   _asm
   {
      push 0
      push 1
      push [esp+0Ch]      //   Pointer to the hMod argument
        mov eax, 0xDEADBEEF   //   Patch this in with the real value at run-time

      call eax         //   MSVC++ doesn't like direct absolute calls, so we have to be
                     //   clever about it.

      ret               //   Don't have to clean up the stack because the calling function
                     //   is just going to call ExitThread() immediately after this
                     //   function returns.
   }
}

//   Marker for the end of the DllCall_stub function
__declspec(naked) void DC_stubend(void) { }   

int main(int argc, char **argv)
{
   //   Just my test values...Cmdline.dll is a plugin that comes with
   //   Olly Debug 1.10
   MapRemoteModule(GetProcessIdByName("notepad.exe"), "Cmdline.dll");
   return 0;
}

bool MapRemoteModule(unsigned long pId, char *module)
{
   IMAGE_DOS_HEADER *dosHd;
   IMAGE_NT_HEADERS *ntHd;

   HANDLE hFile = CreateFile(module,
      GENERIC_READ,
      FILE_SHARE_READ | FILE_SHARE_WRITE,
      NULL,
      OPEN_EXISTING,
      FILE_ATTRIBUTE_NORMAL,
      NULL);

   if(hFile == INVALID_HANDLE_VALUE)
      return false;

   unsigned int fSize;

   if(GetFileAttributes(module) & FILE_ATTRIBUTE_COMPRESSED)
      fSize = GetCompressedFileSize(module, NULL);
   else
      fSize = GetFileSize(hFile, NULL);

   unsigned char *dllBin = new unsigned char[fSize];
   unsigned int nBytes;

   ReadFile(hFile, dllBin, fSize, (LPDWORD)&nBytes, FALSE);
   CloseHandle(hFile);

   //   Every PE file contains a little DOS stub for backwards compatibility
   //   it's only real relevance is that it contains a pointer to the actual
   //   PE header.
   dosHd = MakePtr(IMAGE_DOS_HEADER *, dllBin, 0);

   //   Make sure we got a valid DOS header
   if(dosHd->e_magic != IMAGE_DOS_SIGNATURE)
   {
      delete dllBin;
      return false;
   }

   //   Get the real PE header from the DOS stub header
   ntHd = MakePtr(IMAGE_NT_HEADERS *, dllBin, dosHd->e_lfanew);

   //   Verify the PE header
   if(ntHd->Signature != IMAGE_NT_SIGNATURE)
   {
      delete dllBin;
      return false;
   }

   HANDLE hProcess = OpenProcess(PROCESS_ALL_ACCESS, FALSE, pId);

   if(!hProcess)
      return false;

   //   Allocate space for the module in the remote process
   void *moduleBase = VirtualAllocEx(hProcess,
      NULL,
      ntHd->OptionalHeader.SizeOfImage,
      MEM_COMMIT | MEM_RESERVE,
      PAGE_EXECUTE_READWRITE);

   //   Make sure we got the memory space we wanted
   if(!moduleBase)
      return false;

   //   Allocate space for our stub
   void *stubBase = VirtualAllocEx(hProcess,
      NULL,
      MakeDelta(SIZE_T, DC_stubend, DllCall_stub),
      MEM_COMMIT | MEM_RESERVE,
      PAGE_EXECUTE_READWRITE);

   //   Make sure we got the memory space we wanted
   if(!stubBase)
      return false;

   //   Fix up the import table of the new module
   IMAGE_IMPORT_DESCRIPTOR *impDesc = (IMAGE_IMPORT_DESCRIPTOR *)GetPtrFromRVA(
      (DWORD)(ntHd->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress),
      ntHd,
      (PBYTE)dllBin);

   if(ntHd->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].Size)
      FixImports(pId,
         (unsigned char *)dllBin,
         ntHd,
         impDesc);
   
   //   Fix "base relocations" of the new module.  Base relocations are places
   //   in the module that use absolute addresses to reference data.  Since
   //   the base address of the module can be different at different times,
   //   the base relocation data is necessary to make the module loadable
   //   at any address.
   IMAGE_BASE_RELOCATION *reloc = (IMAGE_BASE_RELOCATION *)GetPtrFromRVA(
      (DWORD)(ntHd->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress),
      ntHd,
      (PBYTE)dllBin);

   if(ntHd->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].Size)
      FixRelocs(dllBin,
         moduleBase,
         ntHd,
         reloc,
         ntHd->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].Size);

   //   Write the PE header into the remote process's memory space
   WriteProcessMemory(hProcess,
      moduleBase,
      dllBin,
      ntHd->FileHeader.SizeOfOptionalHeader + sizeof(ntHd->FileHeader) + sizeof(ntHd->Signature),
      (SIZE_T *)&nBytes);

   //   Map the sections into the remote process(they need to be aligned
   //   along their virtual addresses)
   MapSections(hProcess, moduleBase, dllBin, ntHd);
   
   //   Change the page protection on the DllCall_stub function from PAGE_EXECUTE_READ
   //   to PAGE_EXECUTE_READWRITE, so we can patch it.
   VirtualProtect((LPVOID)DllCall_stub,
      MakeDelta(SIZE_T, DC_stubend, DllCall_stub),
      PAGE_EXECUTE_READWRITE,
      (DWORD *)&nBytes);

   //   Patch the stub so it calls the correct address
   *MakePtr(unsigned long *, DllCall_stub, 9) =
      MakePtr(unsigned long, moduleBase, ntHd->OptionalHeader.AddressOfEntryPoint);


   //   Write the stub into the remote process
   WriteProcessMemory(hProcess,
      stubBase,
      (LPVOID)DllCall_stub,
      MakeDelta(SIZE_T, DC_stubend, DllCall_stub),
      (SIZE_T *)&nBytes);

   //   Execute our stub in the remote process
   CreateRemoteThread(hProcess,
      NULL,
      0,
      (LPTHREAD_START_ROUTINE)stubBase,
      moduleBase,      //   Pass the base address of the module as the argument to the stub.
                  //   All a module handle is, is the base address of the module(except
                  //   in windows CE), so we're really passing a handle to the module
                  //   so that it can refer to itself, create dialogs, etc..
      0,
      NULL);

   delete dllBin;
   return true;
}

bool MapSections(HANDLE hProcess, void *moduleBase, void *dllBin, IMAGE_NT_HEADERS *ntHd)
{
   IMAGE_SECTION_HEADER *header = IMAGE_FIRST_SECTION(ntHd);
   unsigned int nBytes = 0;
   unsigned int virtualSize = 0;
   unsigned int n = 0;

   //   Loop through the list of sections
   for(unsigned int i = 0; ntHd->FileHeader.NumberOfSections; i++)
   {
      //   Once we've reached the SizeOfImage, the rest of the sections
      //   don't need to be mapped, if there are any.
      if(nBytes >= ntHd->OptionalHeader.SizeOfImage)
         break;
     
      WriteProcessMemory(hProcess,
         MakePtr(LPVOID, moduleBase, header->VirtualAddress),
         MakePtr(LPCVOID, dllBin, header->PointerToRawData),
         header->SizeOfRawData,
         (LPDWORD)&n);

      virtualSize = header->VirtualAddress;
      header++;
      virtualSize = header->VirtualAddress - virtualSize;
      nBytes += virtualSize;

      //   Set the proper page protections for this section.
      //   This really could be skipped, but it's not that
      //   hard to implement and it makes it more like a
      //   real loader.
      VirtualProtectEx(hProcess,
         MakePtr(LPVOID, moduleBase, header->VirtualAddress),
         virtualSize,
         header->Characteristics & 0x00FFFFFF,
         NULL);
   }

   return true;
}

bool FixImports(unsigned long pId, void *base, IMAGE_NT_HEADERS *ntHd, IMAGE_IMPORT_DESCRIPTOR *impDesc)
{
   char *module;

   //   Loop through all the required modules
   while((module = (char *)GetPtrFromRVA((DWORD)(impDesc->Name), ntHd, (PBYTE)base)))
   {
      //   If the library is already loaded(like kernel32.dll or ntdll.dll) LoadLibrary will
      //   just return the handle to that module.
        HMODULE localMod = LoadLibrary(module);

      //   If the module isn't loaded in the remote process, we recursively call the
      //   module mapping code.  This has the added benefit of ensuring that any of
      //   the current modules dependencies will be just as invisble as this one.
      if(!GetRemoteModuleHandle(pId, module))
         MapRemoteModule(pId, module);
       
      //   Lookup the first import thunk for this module
      //   NOTE: It is possible this module could forward functions...which is something
      //   that I really should handle.  Maybe i'll add support for forwared functions
      //   a little bit later.
      IMAGE_THUNK_DATA *itd =
         (IMAGE_THUNK_DATA *)GetPtrFromRVA((DWORD)(impDesc->FirstThunk), ntHd, (PBYTE)base);

      while(itd->u1.AddressOfData)
      {
         IMAGE_IMPORT_BY_NAME *iibn;
         iibn = (IMAGE_IMPORT_BY_NAME *)GetPtrFromRVA((DWORD)(itd->u1.AddressOfData), ntHd, (PBYTE)base);

             itd->u1.Function = MakePtr(DWORD, GetRemoteProcAddress(pId,
            module,
            (char *)iibn->Name), 0);

         itd++;
      }       
      impDesc++;
   }
   
   return true;
}

bool FixRelocs(void *base, void *rBase, IMAGE_NT_HEADERS *ntHd, IMAGE_BASE_RELOCATION *reloc, unsigned int size)
{
   unsigned long ImageBase = ntHd->OptionalHeader.ImageBase;
   unsigned int nBytes = 0;

   unsigned long delta = MakeDelta(unsigned long, rBase, ImageBase);

   while(1)
   {
      unsigned long *locBase =
         (unsigned long *)GetPtrFromRVA((DWORD)(reloc->VirtualAddress), ntHd, (PBYTE)base);
      unsigned int numRelocs = (reloc->SizeOfBlock - sizeof(IMAGE_BASE_RELOCATION)) / sizeof(WORD);

      if(nBytes >= size) break;

      unsigned short *locData = MakePtr(unsigned short *, reloc, sizeof(IMAGE_BASE_RELOCATION));
      for(unsigned int i = 0; i < numRelocs; i++)
      {       
         if(((*locData >> 12) & IMAGE_REL_BASED_HIGHLOW))
             *MakePtr(unsigned long *, locBase, (*locData & 0x0FFF)) += delta;

         locData++;
      }

      nBytes += reloc->SizeOfBlock;
      reloc = (IMAGE_BASE_RELOCATION *)locData;
   }

   return true;
}


FARPROC GetRemoteProcAddress(unsigned long pId, char *module, char *func)
{
   HMODULE remoteMod = GetRemoteModuleHandle(pId, module);
   HMODULE localMod = GetModuleHandle(module);

   //   Account for potential differences in base address
   //   of modules in different processes.
   unsigned long delta = MakeDelta(unsigned long, remoteMod, localMod);
   return MakePtr(FARPROC, GetProcAddress(localMod, func), delta);
}

unsigned long GetProcessIdByName(char *process)
{
   PROCESSENTRY32 pe;
   HANDLE thSnapshot;
   BOOL retval, ProcFound = false;

   thSnapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);

   if(thSnapshot == INVALID_HANDLE_VALUE)
   {
      MessageBox(NULL, "Error: unable to create toolhelp snapshot", "Loader", NULL);
      return false;
   }

   pe.dwSize = sizeof(PROCESSENTRY32);

    retval = Process32First(thSnapshot, &pe);

   while(retval)
   {
      if(StrStrI(pe.szExeFile, process) )
      {
         ProcFound = true;
         break;
      }

      retval    = Process32Next(thSnapshot,&pe);
      pe.dwSize = sizeof(PROCESSENTRY32);
   }

   return pe.th32ProcessID;
}

HMODULE GetRemoteModuleHandle(unsigned long pId, char *module)
{
   MODULEENTRY32 modEntry;
   HANDLE tlh = CreateToolhelp32Snapshot(TH32CS_SNAPMODULE, pId);

   modEntry.dwSize = sizeof(MODULEENTRY32);
    Module32First(tlh, &modEntry);

   do
   {
      if(!stricmp(modEntry.szModule, module))
         return modEntry.hModule;
      modEntry.dwSize = sizeof(MODULEENTRY32);
   }
   while(Module32Next(tlh, &modEntry));

   return NULL;
}

//   Matt Pietrek's function
PIMAGE_SECTION_HEADER GetEnclosingSectionHeader(DWORD rva, PIMAGE_NT_HEADERS pNTHeader)
{
    PIMAGE_SECTION_HEADER section = IMAGE_FIRST_SECTION(pNTHeader);
    unsigned int i;
   
    for ( i = 0; i < pNTHeader->FileHeader.NumberOfSections; i++, section++ )
    {
      // This 3 line idiocy is because Watcom's linker actually sets the
      // Misc.VirtualSize field to 0.  (!!! - Retards....!!!)
      DWORD size = section->Misc.VirtualSize;
      if ( 0 == size )
         size = section->SizeOfRawData;
         
        // Is the RVA within this section?
        if ( (rva >= section->VirtualAddress) &&
             (rva < (section->VirtualAddress + size)))
            return section;
    }
   
    return 0;
}

//   This function is also Pietrek's
LPVOID GetPtrFromRVA( DWORD rva, IMAGE_NT_HEADERS *pNTHeader, PBYTE imageBase )
{
   PIMAGE_SECTION_HEADER pSectionHdr;
   INT delta;
     
   pSectionHdr = GetEnclosingSectionHeader( rva, pNTHeader );
   if ( !pSectionHdr )
      return 0;

   delta = (INT)(pSectionHdr->VirtualAddress-pSectionHdr->PointerToRawData);
   return (PVOID) ( imageBase + rva - delta );
}