mirror of https://github.com/Kkevsterrr/geneva
64 lines
2.2 KiB
Python
64 lines
2.2 KiB
Python
"""
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Censor 2 ----> CENSOR 1
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Designed to be run by the evaluator.
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TCP Censor that synchronizes on first SYN only, works 100% of the time, sends 5 RSTs to client.
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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 Censor2(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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def check_censor(self, packet):
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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: %s", layers.packet.Packet._str_packet(packet))
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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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if packet["TCP"].sprintf('%TCP.flags%') == "S":
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self.tcb = packet["TCP"].seq + 1
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self.logger.debug("Synchronizing TCB on packet: %s", layers.packet.Packet._str_packet(packet))
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return False
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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: %s", layers.packet.Packet._str_packet(packet))
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return False
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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: %s", 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("Censor 2 exception caught.")
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return False
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def censor(self, scapy_packet):
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"""
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Send 5 resets to the client.
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"""
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rst = IP(src=scapy_packet[IP].dst, dst=scapy_packet[IP].src)/TCP(dport=scapy_packet[TCP].sport, sport=scapy_packet[TCP].dport, ack=scapy_packet[TCP].seq+len(str(scapy_packet[TCP].payload)), seq=scapy_packet[TCP].ack, flags="R")
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for i in range(0, 5):
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self.mysend(rst)
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