/// <summary>
/// Relocates a module in memory.
/// </summary>
/// <author>Ruben Boonen (@FuzzySec)</author>
/// <param name="PEINFO">Module meta data struct (PE.PE_META_DATA).</param>
/// <param name="ModuleMemoryBase">Base address of the module in memory.</param>
/// <returns>void</returns>
public static void RelocateModule(PE.PE_META_DATA PEINFO, IntPtr ModuleMemoryBase)
{
PE.IMAGE_DATA_DIRECTORY idd = PEINFO.Is32Bit ? PEINFO.OptHeader32.BaseRelocationTable : PEINFO.OptHeader64.BaseRelocationTable;
Int64 ImageDelta = PEINFO.Is32Bit ? (Int64)((UInt64)ModuleMemoryBase - PEINFO.OptHeader32.ImageBase) :
(Int64)((UInt64)ModuleMemoryBase - PEINFO.OptHeader64.ImageBase);
// Ptr for the base reloc table
IntPtr pRelocTable = (IntPtr)((UInt64)ModuleMemoryBase + idd.VirtualAddress);
Int32 nextRelocTableBlock = -1;
// Loop reloc blocks
while (nextRelocTableBlock != 0)
{
PE.IMAGE_BASE_RELOCATION ibr = new PE.IMAGE_BASE_RELOCATION();
ibr = (PE.IMAGE_BASE_RELOCATION)Marshal.PtrToStructure(pRelocTable, typeof(PE.IMAGE_BASE_RELOCATION));
Int64 RelocCount = ((ibr.SizeOfBlock - Marshal.SizeOf(ibr)) / 2);
for (int i = 0; i < RelocCount; i++)
{
// Calculate reloc entry ptr
IntPtr pRelocEntry = (IntPtr)((UInt64)pRelocTable + (UInt64)Marshal.SizeOf(ibr) + (UInt64)(i * 2));
UInt16 RelocValue = (UInt16)Marshal.ReadInt16(pRelocEntry);
// Parse reloc value
// The type should only ever be 0x0, 0x3, 0xA
// https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#base-relocation-types
UInt16 RelocType = (UInt16)(RelocValue >> 12);
UInt16 RelocPatch = (UInt16)(RelocValue & 0xfff);
// Perform relocation
if (RelocType != 0) // IMAGE_REL_BASED_ABSOLUTE (0 -> skip reloc)
{
try
{
IntPtr pPatch = (IntPtr)((UInt64)ModuleMemoryBase + ibr.VirtualAdress + RelocPatch);
if (RelocType == 0x3) // IMAGE_REL_BASED_HIGHLOW (x86)
{
Int32 OriginalPtr = Marshal.ReadInt32(pPatch);
Marshal.WriteInt32(pPatch, (OriginalPtr + (Int32)ImageDelta));
}
else // IMAGE_REL_BASED_DIR64 (x64)
{
Int64 OriginalPtr = Marshal.ReadInt64(pPatch);
Marshal.WriteInt64(pPatch, (OriginalPtr + ImageDelta));
}
}
catch
{
throw new InvalidOperationException("Memory access violation.");
}
}
}
// Check for next block
pRelocTable = (IntPtr)((UInt64)pRelocTable + ibr.SizeOfBlock);
nextRelocTableBlock = Marshal.ReadInt32(pRelocTable);
}
}
/// <summary>
/// Rewrite IAT for manually mapped module.
/// </summary>
/// <author>Ruben Boonen (@FuzzySec)</author>
/// <param name="PEINFO">Module meta data struct (PE.PE_META_DATA).</param>
/// <param name="ModuleMemoryBase">Base address of the module in memory.</param>
/// <returns>void</returns>
public static void RewriteModuleIAT(PE.PE_META_DATA PEINFO, IntPtr ModuleMemoryBase)
{
PE.IMAGE_DATA_DIRECTORY idd = PEINFO.Is32Bit ? PEINFO.OptHeader32.ImportTable : PEINFO.OptHeader64.ImportTable;
// Ptr for the base import directory
IntPtr pImportTable = (IntPtr)((UInt64)ModuleMemoryBase + idd.VirtualAddress);
// Get API Set mapping dictionary if on Win10+
Execute.Native.OSVERSIONINFOEX OSVersion = new Execution.Native.OSVERSIONINFOEX();
DynamicInvoke.Native.RtlGetVersion(ref OSVersion);
Dictionary <string, string> ApiSetDict = new Dictionary <string, string>();
if (OSVersion.MajorVersion >= 10)
{
ApiSetDict = DynamicInvoke.Generic.GetApiSetMapping();
}
// Loop IID's
int counter = 0;
Execute.Win32.Kernel32.IMAGE_IMPORT_DESCRIPTOR iid = new Execute.Win32.Kernel32.IMAGE_IMPORT_DESCRIPTOR();
iid = (Execute.Win32.Kernel32.IMAGE_IMPORT_DESCRIPTOR)Marshal.PtrToStructure(
(IntPtr)((UInt64)pImportTable + (uint)(Marshal.SizeOf(iid) * counter)),
typeof(Execute.Win32.Kernel32.IMAGE_IMPORT_DESCRIPTOR)
);
while (iid.Name != 0)
{
// Get DLL
string DllName = string.Empty;
try
{
DllName = Marshal.PtrToStringAnsi((IntPtr)((UInt64)ModuleMemoryBase + iid.Name));
}
catch { }
// Loop imports
if (DllName == string.Empty)
{
throw new InvalidOperationException("Failed to read DLL name.");
}
else
{
// API Set DLL?
if (OSVersion.MajorVersion >= 10 && (DllName.StartsWith("api-") || DllName.StartsWith("ext-")) &&
ApiSetDict.ContainsKey(DllName) && ApiSetDict[DllName].Length > 0)
{
// Not all API set DLL's have a registered host mapping
DllName = ApiSetDict[DllName];
}
// Check and / or load DLL
IntPtr hModule = DynamicInvoke.Generic.GetLoadedModuleAddress(DllName);
if (hModule == IntPtr.Zero)
{
hModule = DynamicInvoke.Generic.LoadModuleFromDisk(DllName);
if (hModule == IntPtr.Zero)
{
throw new FileNotFoundException(DllName + ", unable to find the specified file.");
}
}
// Loop thunks
if (PEINFO.Is32Bit)
{
PE.IMAGE_THUNK_DATA32 oft_itd = new PE.IMAGE_THUNK_DATA32();
for (int i = 0; true; i++)
{
oft_itd = (PE.IMAGE_THUNK_DATA32)Marshal.PtrToStructure((IntPtr)((UInt64)ModuleMemoryBase + iid.OriginalFirstThunk + (UInt32)(i * (sizeof(UInt32)))), typeof(PE.IMAGE_THUNK_DATA32));
IntPtr ft_itd = (IntPtr)((UInt64)ModuleMemoryBase + iid.FirstThunk + (UInt64)(i * (sizeof(UInt32))));
if (oft_itd.AddressOfData == 0)
{
break;
}
if (oft_itd.AddressOfData < 0x80000000) // !IMAGE_ORDINAL_FLAG32
{
IntPtr pImpByName = (IntPtr)((UInt64)ModuleMemoryBase + oft_itd.AddressOfData + sizeof(UInt16));
IntPtr pFunc = IntPtr.Zero;
pFunc = DynamicInvoke.Generic.GetNativeExportAddress(hModule, Marshal.PtrToStringAnsi(pImpByName));
// Write ProcAddress
Marshal.WriteInt32(ft_itd, pFunc.ToInt32());
}
else
{
ulong fOrdinal = oft_itd.AddressOfData & 0xFFFF;
IntPtr pFunc = IntPtr.Zero;
pFunc = DynamicInvoke.Generic.GetNativeExportAddress(hModule, (short)fOrdinal);
// Write ProcAddress
Marshal.WriteInt32(ft_itd, pFunc.ToInt32());
}
}
}
else
{
PE.IMAGE_THUNK_DATA64 oft_itd = new PE.IMAGE_THUNK_DATA64();
for (int i = 0; true; i++)
{
oft_itd = (PE.IMAGE_THUNK_DATA64)Marshal.PtrToStructure((IntPtr)((UInt64)ModuleMemoryBase + iid.OriginalFirstThunk + (UInt64)(i * (sizeof(UInt64)))), typeof(PE.IMAGE_THUNK_DATA64));
IntPtr ft_itd = (IntPtr)((UInt64)ModuleMemoryBase + iid.FirstThunk + (UInt64)(i * (sizeof(UInt64))));
if (oft_itd.AddressOfData == 0)
{
break;
}
if (oft_itd.AddressOfData < 0x8000000000000000) // !IMAGE_ORDINAL_FLAG64
{
IntPtr pImpByName = (IntPtr)((UInt64)ModuleMemoryBase + oft_itd.AddressOfData + sizeof(UInt16));
IntPtr pFunc = IntPtr.Zero;
pFunc = DynamicInvoke.Generic.GetNativeExportAddress(hModule, Marshal.PtrToStringAnsi(pImpByName));
// Write pointer
Marshal.WriteInt64(ft_itd, pFunc.ToInt64());
}
else
{
ulong fOrdinal = oft_itd.AddressOfData & 0xFFFF;
IntPtr pFunc = IntPtr.Zero;
pFunc = DynamicInvoke.Generic.GetNativeExportAddress(hModule, (short)fOrdinal);
// Write pointer
Marshal.WriteInt64(ft_itd, pFunc.ToInt64());
}
}
}
counter++;
iid = (Execute.Win32.Kernel32.IMAGE_IMPORT_DESCRIPTOR)Marshal.PtrToStructure(
(IntPtr)((UInt64)pImportTable + (uint)(Marshal.SizeOf(iid) * counter)),
typeof(Execute.Win32.Kernel32.IMAGE_IMPORT_DESCRIPTOR)
);
}
}
}