#!/usr/bin/lua 
--[===[ 
#(c) 2010 Adam Pridgen adam@praetoriangrp.com, adam.pridgen@thecoverofnight.com
# dd_remote.lua:
# 		Provides a LUA command script that will do the follwing:
#		1) dd "count" bytes of "bs" from a binary file or block device to temp file.  
#		2) Read the temp file and helify the contents
#		3) echo the string to telnet to send it to a remote host
#
#
# GPLv3 License
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
]===]
function hexlify(infile)
	local f = io.open(infile, 'rb')
	local bytes = f:read('*all')
	f:close()
	local result = ""
	for b in string.gfind(bytes, ".") do
		result = result .. string.format('%02X', string.byte(b))
	end
	return result
end

local bs = 512
local count = 1
local src = arg[1]
local dst = arg[2]
local fsize = arg[3]
local host = arg[4]
local port = arg[5]
local tail = arg[6]

local offset = 0
local end_ = tonumber(fsize)
local base_dd = 'dd if=%s of=%s bs=%u count=%u skip=%u'
local base_send = 'echo %s | telnet %s %s'



if (src == nil or dst == nil or host == nil or fsize == nil or port == nil or tail == nil) then
	print ("usage:\n" .. arg[0] .. " src temp_file filesize remotehost port expected end string\n")
	os.exit(-1)
end



while offset*bs <= end_ do
	local dd_cmd = string.format(base_dd, src, dst, bs, count, offset)
	os.execute(dd_cmd)
	local data = hexlify(dst)
	local send_cmd = string.format(base_send, data, host, port)
	os.execute(send_cmd)
	offset = offset + count
end

local send_cmd = string.format(base_send, tail, host, port)
os.execute(send_cmd)
print ("Completed the file transfer!")