mirror of https://github.com/Kkevsterrr/geneva
75 lines
2.9 KiB
Python
75 lines
2.9 KiB
Python
"""
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Censor 7 is a IP dropping TCB Teardown censor. It only tears down a TCB
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if the full tuple of the TCB matches (src, dst, sport, dport).
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Does not check if the SEQ/ACK are in window for the FIN/RST.
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"""
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import logging
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import layers.packet
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logging.getLogger("scapy.runtime").setLevel(logging.ERROR)
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from scapy.all import IP, TCP
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from censors.censor import Censor
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class Censor7(Censor):
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def __init__(self, environment_id, forbidden, log_dir, log_level, port, queue_num):
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Censor.__init__(self, environment_id, log_dir, log_level, port, queue_num)
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self.forbidden = forbidden
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self.tcb = {}
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self.drop_all_from = None
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def check_censor(self, packet, verbose=False):
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"""
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Check if the censor should run against this packet. Returns true or false.
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"""
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try:
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self.logger.debug("Inbound packet to censor: " + layers.packet.Packet._str_packet(packet))
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if self.drop_all_from == packet["IP"].src:
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self.logger.debug("Dropping all from this IP %s..." % self.drop_all_from)
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return True
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# Only censor TCP packets for now
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if "TCP" not in packet:
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return False
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# Clients can close connections with any of these flags
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if packet["TCP"].sprintf('%TCP.flags%') in ["R", "RA", "F"]:
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# If a TCB has already been setup, check that this packet matches it
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if self.tcb and \
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packet["IP"].src in self.tcb["ips"] and \
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packet["IP"].dst in self.tcb["ips"] and \
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packet["TCP"].dport in self.tcb["ports"] and \
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packet["TCP"].sport in self.tcb["ports"]:
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self.tcb = None
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self.logger.debug(("Tearing down TCB on packet " + layers.packet.Packet._str_packet(packet)))
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return False
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elif not self.tcb and self.tcb is not None:
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self.tcb["ips"] = [packet["IP"].src, packet["IP"].dst]
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self.tcb["ports"] = [packet["TCP"].sport, packet["TCP"].dport]
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if self.tcb is None:
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self.logger.debug("Ignoring packet: " + layers.packet.Packet._str_packet(packet))
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return False
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# Check if any forbidden words appear in the packet payload
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for keyword in self.forbidden:
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if keyword in self.get_payload(packet):
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self.logger.debug("Packet triggered censor: " + layers.packet.Packet._str_packet(packet))
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return True
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return False
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except Exception:
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self.logger.exception("Exception caught by Censor 7")
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return False
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def censor(self, scapy_packet):
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"""
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Marks this IP to be dropped in the future and drops this packet.
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"""
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self.drop_all_from = scapy_packet["IP"].src
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self.logger.debug("Marking IP %s for dropping..." % self.drop_all_from)
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return "drop"
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