344 lines
9.8 KiB
Ruby
344 lines
9.8 KiB
Ruby
require 'rex/socket'
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require 'rex/proto/tftp'
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require 'tempfile'
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module Rex
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module Proto
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module TFTP
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#
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# TFTP Client class
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#
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# Note that TFTP has blocks, and so does Ruby. Watch out with the variable names!
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#
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# The big gotcha right now is that setting the mode between octet, netascii, or
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# anything else doesn't actually do anything other than declare it to the
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# server.
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#
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# Also, since TFTP clients act as both clients and servers, we use two
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# threads to handle transfers, regardless of the direction. For this reason,
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# the transfer actions are nonblocking; if you need to see the
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# results of a transfer before doing something else, check the boolean complete
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# attribute and any return data in the :status attribute. It's a little
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# weird like that.
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#
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# Finally, most (all?) clients will alter the data in netascii mode in order
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# to try to conform to the RFC standard for what "netascii" means, but there are
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# ambiguities in implementations on things like if nulls are allowed, what
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# to do with Unicode, and all that. For this reason, "octet" is default, and
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# if you want to send "netascii" data, it's on you to fix up your source data
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# prior to sending it.
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#
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class Client
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attr_accessor :local_host, :local_port, :peer_host, :peer_port
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attr_accessor :threads, :context, :server_sock, :client_sock
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attr_accessor :local_file, :remote_file, :mode, :action
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attr_accessor :complete, :recv_tempfile, :status
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attr_accessor :block_size # This definitely breaks spec, should only use for fuzz/sploit.
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# Returns an array of [code, type, msg]. Data packets
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# specifically will /not/ unpack, since that would drop any trailing spaces or nulls.
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def parse_tftp_response(str)
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return nil unless str.length >= 4
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ret = str.unpack("nnA*")
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ret[2] = str[4,str.size] if ret[0] == OpData
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return ret
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end
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def initialize(params)
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self.threads = []
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self.local_host = params["LocalHost"] || "0.0.0.0"
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self.local_port = params["LocalPort"] || (1025 + rand(0xffff-1025))
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self.peer_host = params["PeerHost"] || (raise ArgumentError, "Need a peer host.")
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self.peer_port = params["PeerPort"] || 69
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self.context = params["Context"] || {'Msf' => framework, 'MsfExploit' => self}
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self.local_file = params["LocalFile"]
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self.remote_file = params["RemoteFile"] || (::File.split(self.local_file).last if self.local_file)
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self.mode = params["Mode"] || "octet"
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self.action = params["Action"] || (raise ArgumentError, "Need an action.")
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self.block_size = params["BlockSize"] || 512
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end
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#
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# Methods for both upload and download
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#
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def start_server_socket
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self.server_sock = Rex::Socket::Udp.create(
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'LocalHost' => local_host,
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'LocalPort' => local_port,
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'Context' => context
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)
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if self.server_sock and block_given?
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yield "Started TFTP client listener on #{local_host}:#{local_port}"
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end
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self.threads << Rex::ThreadFactory.spawn("TFTPServerMonitor", false) {
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if block_given?
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monitor_server_sock {|msg| yield msg}
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else
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monitor_server_sock
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end
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}
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end
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def monitor_server_sock
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yield "Listening for incoming ACKs" if block_given?
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res = self.server_sock.recvfrom(65535)
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if res and res[0]
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code, type, data = parse_tftp_response(res[0])
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if code == OpAck and self.action == :upload
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if block_given?
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yield "WRQ accepted, sending the file." if type == 0
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send_data(res[1], res[2]) {|msg| yield msg}
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else
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send_data(res[1], res[2])
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end
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elsif code == OpData and self.action == :download
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if block_given?
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recv_data(res[1], res[2], data) {|msg| yield msg}
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else
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recv_data(res[1], res[2], data)
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end
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elsif code == OpError
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yield("Aborting, got error type:%d, message:'%s'" % [type, data]) if block_given?
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self.status = {:error => [code, type, data]}
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else
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yield("Aborting, got code:%d, type:%d, message:'%s'" % [code, type, data]) if block_given?
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self.status = {:error => [code, type, data]}
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end
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end
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stop
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end
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def monitor_client_sock
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res = self.client_sock.recvfrom(65535)
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if res[1] # Got a response back, so that's never good; Acks come back on server_sock.
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code, type, data = parse_tftp_response(res[0])
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yield("Aborting, got code:%d, type:%d, message:'%s'" % [code, type, data]) if block_given?
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self.status = {:error => [code, type, data]}
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stop
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end
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end
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def stop
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self.complete = true
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begin
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self.server_sock.close
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self.client_sock.close
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self.server_sock = nil
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self.client_sock = nil
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self.threads.each {|t| t.kill}
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rescue
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nil
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end
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end
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#
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# Methods for download
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#
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def rrq_packet
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req = [OpRead, self.remote_file, self.mode]
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packstr = "na#{self.remote_file.length+1}a#{self.mode.length+1}"
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req.pack(packstr)
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end
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def ack_packet(blocknum=0)
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req = [OpAck, blocknum].pack("nn")
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end
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def send_read_request(&block)
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self.status = nil
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self.complete = false
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if block_given?
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start_server_socket {|msg| yield msg}
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else
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start_server_socket
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end
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self.client_sock = Rex::Socket::Udp.create(
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'PeerHost' => peer_host,
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'PeerPort' => peer_port,
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'LocalHost' => local_host,
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'LocalPort' => local_port,
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'Context' => context
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)
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self.client_sock.sendto(rrq_packet, peer_host, peer_port)
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self.threads << Rex::ThreadFactory.spawn("TFTPClientMonitor", false) {
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if block_given?
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monitor_client_sock {|msg| yield msg}
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else
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monitor_client_sock
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end
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}
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until self.complete
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return self.status
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end
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end
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def recv_data(host, port, first_block)
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self.recv_tempfile = Rex::Quickfile.new('msf-tftp')
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recvd_blocks = 1
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if block_given?
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yield "Source file: #{self.remote_file}, destination file: #{self.local_file}"
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yield "Received and acknowledged #{first_block.size} in block #{recvd_blocks}"
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end
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if block_given?
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write_and_ack_data(first_block,1,host,port) {|msg| yield msg}
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else
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write_and_ack_data(first_block,1,host,port)
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end
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current_block = first_block
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while current_block.size == 512
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res = self.server_sock.recvfrom(65535)
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if res and res[0]
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code, block_num, current_block = parse_tftp_response(res[0])
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if code == 3
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if block_given?
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write_and_ack_data(current_block,block_num,host,port) {|msg| yield msg}
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else
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write_and_ack_data(current_block,block_num,host,port)
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end
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recvd_blocks += 1
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else
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yield("Aborting, got code:%d, type:%d, message:'%s'" % [code, type, msg]) if block_given?
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stop
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end
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end
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end
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if block_given?
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yield("Transferred #{self.recv_tempfile.size} bytes in #{recvd_blocks} blocks, download complete!")
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end
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self.status = {:success => [
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self.local_file,
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self.remote_file,
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self.recv_tempfile.size,
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recvd_blocks.size]
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}
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self.recv_tempfile.close
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stop
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end
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def write_and_ack_data(data,blocknum,host,port)
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self.recv_tempfile.write(data)
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self.recv_tempfile.flush
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req = ack_packet(blocknum)
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self.server_sock.sendto(req, host, port)
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yield "Received and acknowledged #{data.size} in block #{blocknum}" if block_given?
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end
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#
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# Methods for upload
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#
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def wrq_packet
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req = [OpWrite, self.remote_file, self.mode]
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packstr = "na#{self.remote_file.length+1}a#{self.mode.length+1}"
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req.pack(packstr)
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end
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# Note that the local filename for uploading need not be a real filename --
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# if it begins with DATA: it can be any old string of bytes. If it's missing
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# completely, then just quit.
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def blockify_file_or_data
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if self.local_file =~ /^DATA:(.*)/m
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data = $1
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elsif ::File.file?(self.local_file) and ::File.readable?(self.local_file)
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data = ::File.open(self.local_file, "rb") {|f| f.read f.stat.size} rescue []
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else
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return []
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end
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data_blocks = data.scan(/.{1,#{block_size}}/m)
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# Drop any trailing empty blocks
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if data_blocks.size > 1 and data_blocks.last.empty?
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data_blocks.pop
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end
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return data_blocks
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end
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def send_write_request(&block)
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self.status = nil
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self.complete = false
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if block_given?
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start_server_socket {|msg| yield msg}
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else
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start_server_socket
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end
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self.client_sock = Rex::Socket::Udp.create(
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'PeerHost' => peer_host,
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'PeerPort' => peer_port,
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'LocalHost' => local_host,
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'LocalPort' => local_port,
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'Context' => context
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)
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self.client_sock.sendto(wrq_packet, peer_host, peer_port)
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self.threads << Rex::ThreadFactory.spawn("TFTPClientMonitor", false) {
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if block_given?
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monitor_client_sock {|msg| yield msg}
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else
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monitor_client_sock
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end
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}
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until self.complete
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return self.status
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end
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end
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def send_data(host,port)
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self.status = {:write_allowed => true}
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data_blocks = blockify_file_or_data()
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if data_blocks.empty?
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yield "Closing down since there is no data to send." if block_given?
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self.status = {:success => [self.local_file, self.local_file, 0, 0]}
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return nil
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end
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sent_data = 0
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sent_blocks = 0
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expected_blocks = data_blocks.size
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expected_size = data_blocks.join.size
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if block_given?
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yield "Source file: #{self.local_file =~ /^DATA:/ ? "(Data)" : self.remote_file}, destination file: #{self.remote_file}"
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yield "Sending #{expected_size} bytes (#{expected_blocks} blocks)"
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end
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data_blocks.each_with_index do |data_block,idx|
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req = [OpData, (idx + 1), data_block].pack("nnA*")
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if self.server_sock.sendto(req, host, port) > 0
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sent_data += data_block.size
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end
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res = self.server_sock.recvfrom(65535)
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if res
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code, type, msg = parse_tftp_response(res[0])
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if code == 4
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sent_blocks += 1
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yield "Sent #{data_block.size} bytes in block #{sent_blocks}" if block_given?
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else
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if block_given?
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yield "Got an unexpected response: Code:%d, Type:%d, Message:'%s'. Aborting." % [code, type, msg]
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end
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break
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end
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end
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end
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if block_given?
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if(sent_data == expected_size)
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yield("Transferred #{sent_data} bytes in #{sent_blocks} blocks, upload complete!")
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else
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yield "Upload complete, but with errors."
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end
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end
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if sent_data == expected_size
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self.status = {:success => [
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self.local_file,
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self.remote_file,
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sent_data,
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sent_blocks
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] }
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end
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end
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end
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end
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end
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end
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