private static void PatchRelocations(JLibrary.PortableExecutable.PortableExecutable image, IntPtr pAlloc)
{
IMAGE_DATA_DIRECTORY image_data_directory = image.NTHeader.OptionalHeader.DataDirectory[5];
if (image_data_directory.Size > 0)
{
IMAGE_BASE_RELOCATION image_base_relocation;
uint num = 0;
uint num2 = ((uint)pAlloc.ToInt32()) - image.NTHeader.OptionalHeader.ImageBase;
uint ptrFromRVA = image.GetPtrFromRVA(image_data_directory.VirtualAddress);
uint num4 = (uint)Marshal.SizeOf(typeof(IMAGE_BASE_RELOCATION));
while ((num < image_data_directory.Size) && image.Read <IMAGE_BASE_RELOCATION>((long)ptrFromRVA, SeekOrigin.Begin, out image_base_relocation))
{
int num5 = (int)((image_base_relocation.SizeOfBlock - num4) / 2);
uint num6 = image.GetPtrFromRVA(image_base_relocation.VirtualAddress);
for (int i = 0; i < num5; i++)
{
ushort num7;
if (image.Read <ushort>((ptrFromRVA + num4) + (i << 1), SeekOrigin.Begin, out num7) && (((num7 >> 12) & 3) != 0))
{
uint num8;
uint num10 = num6 + ((uint)(num7 & 0xfff));
if (!image.Read <uint>((long)num10, SeekOrigin.Begin, out num8))
{
throw image.GetLastError();
}
image.Write <uint>(-4L, SeekOrigin.Current, num8 + num2);
}
}
num += image_base_relocation.SizeOfBlock;
ptrFromRVA += image_base_relocation.SizeOfBlock;
}
}
}
private static void PatchImports(JLibrary.PortableExecutable.PortableExecutable image, IntPtr hProcess, int processId)
{
string lpBuffer = string.Empty;
string str2 = string.Empty;
foreach (IMAGE_IMPORT_DESCRIPTOR image_import_descriptor in image.EnumImports())
{
if (image.ReadString((long)image.GetPtrFromRVA(image_import_descriptor.Name), SeekOrigin.Begin, out lpBuffer, -1, null))
{
IMAGE_THUNK_DATA image_thunk_data;
IntPtr zero = IntPtr.Zero;
zero = GetRemoteModuleHandle(lpBuffer, processId);
if (zero.IsNull())
{
throw new FileNotFoundException(string.Format("Unable to load dependent module '{0}'.", lpBuffer));
}
uint ptrFromRVA = image.GetPtrFromRVA(image_import_descriptor.FirstThunkPtr);
uint num2 = (uint)Marshal.SizeOf(typeof(IMAGE_THUNK_DATA));
while (image.Read <IMAGE_THUNK_DATA>((long)ptrFromRVA, SeekOrigin.Begin, out image_thunk_data) && (image_thunk_data.u1.AddressOfData > 0))
{
IntPtr hModule = IntPtr.Zero;
object lpProcName = null;
if ((image_thunk_data.u1.Ordinal & 0x80000000) == 0)
{
if (!image.ReadString((long)(image.GetPtrFromRVA(image_thunk_data.u1.AddressOfData) + 2), SeekOrigin.Begin, out str2, -1, null))
{
throw image.GetLastError();
}
lpProcName = str2;
}
else
{
lpProcName = (ushort)(image_thunk_data.u1.Ordinal & 0xffff);
}
if (!(hModule = WinAPI.GetModuleHandleA(lpBuffer)).IsNull())
{
IntPtr ptr = lpProcName.GetType().Equals(typeof(string)) ? WinAPI.GetProcAddress(hModule, (string)lpProcName) : WinAPI.GetProcAddress(hModule, (uint)(((ushort)lpProcName) & 0xffff));
if (!ptr.IsNull())
{
hModule = zero.Add((long)ptr.Subtract(((long)hModule.ToInt32())).ToInt32());
}
}
else
{
hModule = WinAPI.GetProcAddressEx(hProcess, zero, lpProcName);
}
if (hModule.IsNull())
{
throw new EntryPointNotFoundException(string.Format("Unable to locate imported function '{0}' from module '{1}' in the remote process.", str2, lpBuffer));
}
image.Write <int>((long)ptrFromRVA, SeekOrigin.Begin, hModule.ToInt32());
ptrFromRVA += num2;
}
}
}
}
private static void PatchImports(PortableExecutable image, IntPtr hProcess, int processId)
{
string module = string.Empty;
string fname = string.Empty;
foreach (var desc in image.EnumImports())
{
if (image.ReadString(image.GetPtrFromRVA(desc.Name), SeekOrigin.Begin, out module))
{
IntPtr pModule = IntPtr.Zero;
IntPtr tModule = IntPtr.Zero;
//Thanks to FastLoadDependencies, all dependent modules *should* be loaded into the remote process already.
pModule = GetRemoteModuleHandle(module, processId);
if (pModule.IsNull())
throw new FileNotFoundException(string.Format("Unable to load dependent module '{0}'.", module));
//now have a supposedly valid module handle remote process, all that remains to be done is patch the info.
uint pThunk = image.GetPtrFromRVA(desc.FirstThunkPtr); //despite the fact FirstThunk and OriginalFirstThunk are identical within an unmapped PE, only FirstThunk is looked up after mapping.
uint szThunk = (uint)Marshal.SizeOf(typeof(IMAGE_THUNK_DATA));
IMAGE_THUNK_DATA thunk;
while (image.Read(pThunk, SeekOrigin.Begin, out thunk) && thunk.u1.AddressOfData > 0) //final thunk is signified by a null-filled IMAGE_THUNK_DATA structure.
{
IntPtr remote = IntPtr.Zero;
object procVal = null;
if ((thunk.u1.Ordinal & 0x80000000) == 0) //import by name
{
if (image.ReadString(image.GetPtrFromRVA(thunk.u1.AddressOfData) + 2, SeekOrigin.Begin, out fname)) //get the function name.
procVal = fname;
else
throw image.GetLastError(); //error occurred during memory iteration, this is only a safeguard and shouldn't really ever occur, but the universe loves proving me wrong.
}
else //import by ordinal.
{
procVal = (ushort)(thunk.u1.Ordinal & 0xFFFF);
}
// the following section of code simply aims to reduce overhead. A check is first performed to see if the current module
// is loaded in the current process first, if so it simply uses relative addresses to calculate the function address in the remote
// process. If the module isn't found in our process, a call to GetProcAddressEx is used to find the remote address. Of course, you
// could simply guarantee the first case by calling LoadLibrary internally, but I find that can have unwanted side effects.
if (!(remote = WinAPI.GetModuleHandleA(module)).IsNull())
{
IntPtr local = procVal.GetType().Equals(typeof(string))
? WinAPI.GetProcAddress(remote, (string)procVal)
: WinAPI.GetProcAddress(remote, (uint)((ushort)procVal) & 0x0000FFFF);
if (!local.IsNull())
remote = pModule.Add(local.Subtract(remote.ToInt32()).ToInt32());
}
else
{
remote = WinAPI.GetProcAddressEx(hProcess, pModule, procVal);
}
if (remote.IsNull()) //alas, couldn't find the function.
throw new EntryPointNotFoundException(string.Format("Unable to locate imported function '{0}' from module '{1}' in the remote process.", fname, module));
image.Write<int>(pThunk, SeekOrigin.Begin, remote.ToInt32()); //overwrite the thunk and continue on our merry way.
pThunk += szThunk;
}
}
}
}
private static void PatchRelocations(PortableExecutable image, IntPtr pAlloc)
{
// Base relocations are essentially Microsofts ingenious way of preserving portability in images.
// for all absolute address calls/jmps/references...etc, an entry is made into the base relocation
// table telling the loader exactly where an "absolute" address is being used. This allows the loader
// to iterate through the relocations and patch these absolute values to ensure they are correct when
// the image is loaded somewhere that isn't its preferred base address.
IMAGE_DATA_DIRECTORY relocDir = image.NTHeader.OptionalHeader.DataDirectory[(int)DATA_DIRECTORIES.BaseRelocTable];
if (relocDir.Size > 0) //check if there are in fact any relocations.
{
uint n = 0;
uint delta = (uint)(pAlloc.ToInt32() - image.NTHeader.OptionalHeader.ImageBase); //The difference in loaded/preferred addresses.
uint pReloc = image.GetPtrFromRVA(relocDir.VirtualAddress);
uint szReloc = (uint)Marshal.SizeOf(typeof(IMAGE_BASE_RELOCATION));
IMAGE_BASE_RELOCATION reloc;
while (n < relocDir.Size && image.Read(pReloc, SeekOrigin.Begin, out reloc))
{
// A relocation block consists of an IMAGE_BASE_RELOCATION, and an array of WORDs.
// To calculate the number of relocations (represented by WORDs), just do some simple math.
int nrelocs = (int)((reloc.SizeOfBlock - szReloc) / sizeof(ushort));
uint pageVa = image.GetPtrFromRVA(reloc.VirtualAddress); //The Page RVA for this set of relocations (usually a 4K boundary).
ushort vreloc;
uint old;
for (int i = 0; i < nrelocs; i++)
{
// There are only 2 types of relocations on Intel machines: ABSOLUTE (padding, nothing needs to be done) and HIGHLOW (0x03)
// Highlow means that all 32 bits of the "delta" value need to be added to the relocation value.
if (image.Read(pReloc + szReloc + (i << 1), SeekOrigin.Begin, out vreloc) && (vreloc >> 12 & 3) != 0)
{
uint vp = (uint)(pageVa + (vreloc & 0x0FFF));
if (image.Read<uint>(vp, SeekOrigin.Begin, out old))
image.Write<uint>(-4, SeekOrigin.Current, (uint)(old + delta));
else
throw image.GetLastError(); //unlikely, but I hate crashing targets because something in the PE was messed up.
}
}
n += reloc.SizeOfBlock;
pReloc += reloc.SizeOfBlock;
}
}
}