module Msf

require 'rex/payloads/win32/kernel'

module Exploit::KernelMode

	#
	# The way that the kernel-mode mixin works is by replacing the payload
	# to be encoded with one that encapsulates the kernel-mode payload as
	# well.
	#
	def encode_begin(real_payload, reqs)
		super

		reqs['EncapsulationRoutine'] = Proc.new { |reqs_, raw|
			encapsulate_payload(reqs_, raw)
		}
	end

	#
	# Increase the default delay by five seconds since some kernel-mode
	# payloads may not run immediately.
	#
	def wfs_delay
		super + 5
	end

protected
	
	#
	# Encapsulates the supplied raw payload within a kernel-mode payload.
	#
	def encapsulate_payload(reqs, raw)
		new_raw = nil
		ext_opt = reqs['ExtendedOptions'] || {}

		# Prepend and append any buffers that were specified in the extended
		# options.  This can be used do perform stack adjustments and other 
		# such things against the user-mode payload rather than the
		# encapsulating payload.
		raw = 
			(ext_opt['PrependUser'] || '') +
			raw +
			(ext_opt['AppendUser'] || '')

		# If this is a win32 target platform, try to encapsulate it in a 
		# win32 kernel-mode payload.
		if target_platform.supports?(Msf::Module::PlatformList.win32)
			ext_opt['UserModeStub'] = raw

			new_raw = Rex::Payloads::Win32::Kernel.construct(ext_opt)
		end
	
		# If we did not generate a new payload, then something broke.
		if new_raw.nil?
			raise RuntimeError, "Could not encapsulate payload in kernel-mode payload"
		else
			dlog("Encapsulated user-mode payload size #{raw.length} in kernel-mode payload size #{new_raw.length}", 'core', LEV_1)
		end

		new_raw
	end

end

end