mirror of https://github.com/Kkevsterrr/geneva
87 lines
2.7 KiB
Python
87 lines
2.7 KiB
Python
"""
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Censor 4
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Dropping censor that synchronizes TCB on all SYN and ACK packets.
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"""
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import layers.packet
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import logging
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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 Censor4(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 = 0
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self.drop_all_from = None
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self.num = 0
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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.num += 1
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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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# Initial TCP synchronization
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if "S" == packet["TCP"].sprintf('%TCP.flags%'):
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self.tcb = packet["TCP"].seq + 1
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self.logger.debug(("Synchronizing TCB (%d) on S packet " + layers.packet.Packet._str_packet(packet)) % self.tcb)
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return False
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if "A" == packet["TCP"].sprintf('%TCP.flags%'):
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self.tcb = packet["TCP"].seq
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self.logger.debug(("Synchronizing TCB (%d) on A packet " + layers.packet.Packet._str_packet(packet)) % self.tcb)
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return False
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# If we're tracking this packet stream
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if packet["TCP"].seq == self.tcb:
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self.tcb += len(self.get_payload(packet))
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else:
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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 4")
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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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