module Msf

require 'msf/core/exploit/tcp'

###
#
# This module exposes methods that may be useful to exploits that deal with
# servers that speak the File Transfer Protocol (FTP).
#
###
module Exploit::Remote::Ftp

	include Exploit::Remote::Tcp

	#
	# Creates an instance of an FTP exploit module.
	#
	def initialize(info = {})
		super

		# Register the options that all FTP exploits may make use of.
		register_options(
			[
				Opt::RHOST,
				Opt::RPORT(21),
				OptString.new('FTPUSER', [ false, 'The username to authenticate as', 'anonymous']),
				OptString.new('FTPPASS', [ false, 'The password for the specified username', 'mozilla@example.com'])
			], Msf::Exploit::Remote::Ftp)

		register_advanced_options(
			[
				OptInt.new('FTPTimeout', [ true, 'The number of seconds to wait for a reply from an FTP command', 16])
			], Msf::Exploit::Remote::Ftp)

		register_autofilter_ports([ 21, 2121])
		register_autofilter_services(%W{ ftp })

		@ftpbuff = ""

	end

	#
	# This method establishes an FTP connection to host and port specified by
	# the RHOST and RPORT options, respectively.  After connecting, the banner
	# message is read in and stored in the 'banner' attribute.
	#
	def connect(global = true, verbose = true)
		print_status("Connecting to FTP server #{rhost}:#{rport}...") if verbose

		fd = super(global)

		# Wait for a banner to arrive...
		self.banner = recv_ftp_resp(fd)

		print_status("Connected to target FTP server.") if verbose

		# Return the file descriptor to the caller
		fd
	end

	#
	# Connect and login to the remote FTP server using the credentials
	# that have been supplied in the exploit options.
	#
	def connect_login(global = true, verbose = true)
		ftpsock = connect(global, verbose)

		if !(user and pass)
			print_error("No username and password were supplied, unable to login")
			return false
		end

		print_status("Authenticating as #{user} with password #{pass}...") if verbose
		res = send_user(user, ftpsock)

		if (res !~ /^(331|2)/)
			print_error("The server rejected our username") if verbose
			return false
		end

		if (pass)
			print_status("Sending password...") if verbose
			res = send_pass(pass, ftpsock)
			if (res !~ /^2/)
				print_error("The server rejected our password") if verbose
				return false
			end
		end

		return true
	end

	#
	# This method logs in as the supplied user by transmitting the FTP
	# 'USER <user>' command.
	#
	def send_user(user, nsock = self.sock)
		raw_send("USER #{user}\r\n", nsock)
		recv_ftp_resp(nsock)
	end

	#
	# This method completes user authentication by sending the supplied
	# password using the FTP 'PASS <pass>' command.
	#
	def send_pass(pass, nsock = self.sock)
		raw_send("PASS #{pass}\r\n", nsock)
		recv_ftp_resp(nsock)
	end

	#
	# This method sends a QUIT command. 
	#
	def send_quit(nsock = self.sock)
		raw_send("QUIT\r\n", nsock)
		recv_ftp_resp(nsock)
	end

	#
	# This method sends one command with zero or more parameters
	#
	def send_cmd(args, recv = true, nsock = self.sock)
		cmd = args.join(" ") + "\r\n"
		ret = raw_send(cmd, nsock)
		if (recv)
			return recv_ftp_resp(nsock)
		end
		return ret
	end

	#
	# This method transmits a FTP command and waits for a response.  If one is
	# received, it is returned to the caller.
	#
	def raw_send_recv(cmd, nsock = self.sock)
		nsock.put(cmd)
		nsock.get_once(-1, ftp_timeout)
	end
	
	#
	# This method reads an FTP response based on FTP continuation stuff
	#
	def recv_ftp_resp(nsock = self.sock)
		found_end = FALSE
		resp = ""
		left = ""
		if !@ftpbuff.empty?
			left << @ftpbuff
			@ftpbuff = ""
		end
		while TRUE
			data = nsock.get_once(-1, ftp_timeout)
			if not data
				@ftpbuff << resp
				@ftpbuff << left
				return data
			end
			
			got = left + data
			left = ""
			
			# handle the end w/o newline case
			enlidx = got.rindex(0x0a.chr)
			if enlidx != (got.length-1)
				if not enlidx
					left << got
					next
				else
					left << got.slice!((enlidx+1)..got.length)
				end
			end
			
			# split into lines
			rarr = got.split(/\r?\n/)
			rarr.each do |ln|
				if not found_end
					resp << ln
					resp << "\r\n"
					if ln.length > 3 and ln[3,1] == ' '
						found_end = TRUE
					end
				else
					left << ln
					left << "\r\n"
				end
			end
			if found_end
				@ftpbuff << left
				return resp
			end
		end
	end
	  
	#
	# This method transmits a FTP command and does not wait for a response
	#
	def raw_send(cmd, nsock = self.sock)
		nsock.put(cmd)
	end

	##
	#
	# Wrappers for getters
	#
	##

	#
	# Returns the user string from the 'FTPUSER' option.
	#
	def user
		datastore['FTPUSER'] 
	end

	#
	# Returns the user string from the 'FTPPASS' option.
	#
	def pass
		datastore['FTPPASS']
	end

	#
	# Returns the number of seconds to wait for a FTP reply
	#
	def ftp_timeout
		(datastore['FTPTimeout'] || 10).to_i
	end

protected

	#
	# This attribute holds the banner that was read in after a successful call
	# to connect or connect_login.
	#
	attr_accessor :banner

end

end