metasploit-framework/lib/rex/post/meterpreter/channels/stream.rb

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# -*- coding: binary -*-
require 'rex/io/stream_abstraction'
Implement consistent socket abstraction In current nomenclature, Rex Sockets are objects created by calls to Rex::Socket::<Transport>.create and Rex::Socket.create_... When the LocalHost or Comm parameters are set to remotely routed addresses (currently via Meterpreter sessions), Rex will create a Channel which will abstract communications with the remote end of the session. These channel based abstractions are called pivots, and present in three separate flavors: 1 - TcpClientChannel, a fully abstracted, selectable Socket. 2 - TcpServerChannel, a virtual Channel which distributes client channels. 3 - UdpChannel, a virtual Channel which provides common methods for UDP socket operations, but is not a full (selectable) abstraction. Unfortunately this differentiation results in inconsistent returns from the aforementioned socket creation calls, as the call chain creates parameters and supplies them to the create method on the comm object referenced in the params. The comm object may be a channel, and produce a virtual representation of a socket with functional methods analogous to Sockets, but without a kernel FD. This commit begins the work of ensuring that all calls for socket creation return selectable Rex::Socket objects with semantics familiar to Ruby developers who have not read into the details of Rex::Socket and Rex::Post. ----- Summary of changes: Convert Rex::IO::StreamAbstraction to SocketAbstraction and use the new mixin in StreamAbstraction and DatagramAbstraction. This approach allows for common methods to reuse the abstraction data flow, while initializing separate types of socket obects and an optional monitor as needed. In the Rex::Post::Meterpreter namespace, extract common methods from Stream to a SocketAbstraction mixin, include that mixin in Stream, and add Datagram with the dio_write handler override exported from the current implementation of UdpChannel, also using the mixin. This relies on the Rex::IO work above to implement the proper type of socket abstraction to the Channel descendants. In Rex::Post::Meterpreter::Extensions::Stdapi::Net, convert the UdpChannel to inherit from the Rex::Post::Meterpreter::Datagram class, implementing only the send method at this tier. Convert create_udp_channel to return the local socket side of the datagram abstraction presented analogous to the TcpClientChannel approach used before. ----- Notes and intricacies: In order to implement recvfrom on the UDP abstraction, a shim layer has been put in place to forward the sockaddr information from the remote peer to the local UDP socketpair in the abstraction. This information takes up buffer space in the UDP socket, and in order to maintain compatibility with consumers, the dio_write_handler pushes the data buffer, and in a separate send call, he sockaddr information from the remote socket. On the abstraction side, the recvfrom_nonblock call of the real UDPSocket has been overriden via the mixed in module to call the real method twice, once for the data buffer, and once for the packed sockaddr data. The Rex level consumer for recvfrom calls the underlying nonblock method and expects this exact set of returns (as opposed to what standard library UDPSocket.recvfrom returns, which is a data buffer and an Array of sockaddr data). ----- Testing: Local and lab testing only so far. Test RC script to be added in GH comments. ----- Issues: Currently, sendto on a remote socket does not appear to honor LocalPort which causes DNS responses (#6611) to come from the wrong port to remote clients being serviced over a pivot socket.
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require 'rex/post/meterpreter/channels/socket_abstraction'
module Rex
module Post
module Meterpreter
###
#
# Stream
# ------
#
# This class represents a channel that is streaming. This means
# that sequential data is flowing in either one or both directions.
#
###
class Stream < Rex::Post::Meterpreter::Channel
Implement consistent socket abstraction In current nomenclature, Rex Sockets are objects created by calls to Rex::Socket::<Transport>.create and Rex::Socket.create_... When the LocalHost or Comm parameters are set to remotely routed addresses (currently via Meterpreter sessions), Rex will create a Channel which will abstract communications with the remote end of the session. These channel based abstractions are called pivots, and present in three separate flavors: 1 - TcpClientChannel, a fully abstracted, selectable Socket. 2 - TcpServerChannel, a virtual Channel which distributes client channels. 3 - UdpChannel, a virtual Channel which provides common methods for UDP socket operations, but is not a full (selectable) abstraction. Unfortunately this differentiation results in inconsistent returns from the aforementioned socket creation calls, as the call chain creates parameters and supplies them to the create method on the comm object referenced in the params. The comm object may be a channel, and produce a virtual representation of a socket with functional methods analogous to Sockets, but without a kernel FD. This commit begins the work of ensuring that all calls for socket creation return selectable Rex::Socket objects with semantics familiar to Ruby developers who have not read into the details of Rex::Socket and Rex::Post. ----- Summary of changes: Convert Rex::IO::StreamAbstraction to SocketAbstraction and use the new mixin in StreamAbstraction and DatagramAbstraction. This approach allows for common methods to reuse the abstraction data flow, while initializing separate types of socket obects and an optional monitor as needed. In the Rex::Post::Meterpreter namespace, extract common methods from Stream to a SocketAbstraction mixin, include that mixin in Stream, and add Datagram with the dio_write handler override exported from the current implementation of UdpChannel, also using the mixin. This relies on the Rex::IO work above to implement the proper type of socket abstraction to the Channel descendants. In Rex::Post::Meterpreter::Extensions::Stdapi::Net, convert the UdpChannel to inherit from the Rex::Post::Meterpreter::Datagram class, implementing only the send method at this tier. Convert create_udp_channel to return the local socket side of the datagram abstraction presented analogous to the TcpClientChannel approach used before. ----- Notes and intricacies: In order to implement recvfrom on the UDP abstraction, a shim layer has been put in place to forward the sockaddr information from the remote peer to the local UDP socketpair in the abstraction. This information takes up buffer space in the UDP socket, and in order to maintain compatibility with consumers, the dio_write_handler pushes the data buffer, and in a separate send call, he sockaddr information from the remote socket. On the abstraction side, the recvfrom_nonblock call of the real UDPSocket has been overriden via the mixed in module to call the real method twice, once for the data buffer, and once for the packed sockaddr data. The Rex level consumer for recvfrom calls the underlying nonblock method and expects this exact set of returns (as opposed to what standard library UDPSocket.recvfrom returns, which is a data buffer and an Array of sockaddr data). ----- Testing: Local and lab testing only so far. Test RC script to be added in GH comments. ----- Issues: Currently, sendto on a remote socket does not appear to honor LocalPort which causes DNS responses (#6611) to come from the wrong port to remote clients being serviced over a pivot socket.
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include Rex::Post::Meterpreter::SocketAbstraction
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include Rex::IO::StreamAbstraction
class << self
def cls
return CHANNEL_CLASS_STREAM
end
end
Implement consistent socket abstraction In current nomenclature, Rex Sockets are objects created by calls to Rex::Socket::<Transport>.create and Rex::Socket.create_... When the LocalHost or Comm parameters are set to remotely routed addresses (currently via Meterpreter sessions), Rex will create a Channel which will abstract communications with the remote end of the session. These channel based abstractions are called pivots, and present in three separate flavors: 1 - TcpClientChannel, a fully abstracted, selectable Socket. 2 - TcpServerChannel, a virtual Channel which distributes client channels. 3 - UdpChannel, a virtual Channel which provides common methods for UDP socket operations, but is not a full (selectable) abstraction. Unfortunately this differentiation results in inconsistent returns from the aforementioned socket creation calls, as the call chain creates parameters and supplies them to the create method on the comm object referenced in the params. The comm object may be a channel, and produce a virtual representation of a socket with functional methods analogous to Sockets, but without a kernel FD. This commit begins the work of ensuring that all calls for socket creation return selectable Rex::Socket objects with semantics familiar to Ruby developers who have not read into the details of Rex::Socket and Rex::Post. ----- Summary of changes: Convert Rex::IO::StreamAbstraction to SocketAbstraction and use the new mixin in StreamAbstraction and DatagramAbstraction. This approach allows for common methods to reuse the abstraction data flow, while initializing separate types of socket obects and an optional monitor as needed. In the Rex::Post::Meterpreter namespace, extract common methods from Stream to a SocketAbstraction mixin, include that mixin in Stream, and add Datagram with the dio_write handler override exported from the current implementation of UdpChannel, also using the mixin. This relies on the Rex::IO work above to implement the proper type of socket abstraction to the Channel descendants. In Rex::Post::Meterpreter::Extensions::Stdapi::Net, convert the UdpChannel to inherit from the Rex::Post::Meterpreter::Datagram class, implementing only the send method at this tier. Convert create_udp_channel to return the local socket side of the datagram abstraction presented analogous to the TcpClientChannel approach used before. ----- Notes and intricacies: In order to implement recvfrom on the UDP abstraction, a shim layer has been put in place to forward the sockaddr information from the remote peer to the local UDP socketpair in the abstraction. This information takes up buffer space in the UDP socket, and in order to maintain compatibility with consumers, the dio_write_handler pushes the data buffer, and in a separate send call, he sockaddr information from the remote socket. On the abstraction side, the recvfrom_nonblock call of the real UDPSocket has been overriden via the mixed in module to call the real method twice, once for the data buffer, and once for the packed sockaddr data. The Rex level consumer for recvfrom calls the underlying nonblock method and expects this exact set of returns (as opposed to what standard library UDPSocket.recvfrom returns, which is a data buffer and an Array of sockaddr data). ----- Testing: Local and lab testing only so far. Test RC script to be added in GH comments. ----- Issues: Currently, sendto on a remote socket does not appear to honor LocalPort which causes DNS responses (#6611) to come from the wrong port to remote clients being serviced over a pivot socket.
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module SocketInterface
include Rex::Post::Meterpreter::SocketAbstraction::SocketInterface
def type?
'tcp'
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end
end
end
end; end; end