mirror of https://github.com/Kkevsterrr/geneva
103 lines
2.5 KiB
Python
103 lines
2.5 KiB
Python
import random
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from layers.layer import Layer
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from scapy.all import IP, fuzz, RandIP
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class IPLayer(Layer):
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"""
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Defines an interface to access IP header fields.
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"""
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name = "IP"
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protocol = IP
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_fields = [
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'version',
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'ihl',
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'tos',
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'len',
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'id',
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'flags',
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'frag',
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'ttl',
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'proto',
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'chksum',
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'src',
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'dst',
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'load'
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]
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fields = _fields
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def __init__(self, layer):
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"""
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Initializes the IP layer.
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"""
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Layer.__init__(self, layer)
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self.getters = {
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"flags" : self.get_flags,
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"load" : self.get_load
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}
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self.setters = {
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"flags" : self.set_flags,
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"load" : self.set_load
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}
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self.generators = {
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"src" : self.gen_ip,
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"dst" : self.gen_ip,
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"chksum" : self.gen_chksum,
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"len" : self.gen_len,
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"load" : self.gen_load,
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"flags" : self.gen_flags
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}
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def gen_len(self, field):
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"""
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Generates a valid IP length. Scapy breaks if the length is set to 0, so
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return a random int starting at 1.
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"""
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return random.randint(1, 500)
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def gen_chksum(self, field):
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"""
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Generates a checksum.
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"""
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return random.randint(1, 65535)
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def gen_ip(self, field):
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"""
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Generates an IP address.
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"""
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return RandIP()._fix()
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def get_flags(self, field):
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"""
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Retrieves flags as a string.
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"""
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return str(self.layer.flags)
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def set_flags(self, packet, field, value):
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"""
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Sets the flags field. There is a bug in scapy, if you retrieve an empty
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flags field, it will return "", but you cannot set this value back.
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To reproduce this bug:
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.. code-block:: python
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>>> setattr(IP(), "flags", str(IP().flags)) # raises a ValueError
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To handle this case, this method converts empty string to zero so that
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it can be safely stored.
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"""
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if value == "":
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value = 0
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self.layer.flags = value
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def gen_flags(self, field):
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"""
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Generates random valid flags.
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"""
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sample = fuzz(self.protocol())
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# Since scapy lazily evaluates fuzzing, we first must set a
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# legitimate value for scapy to evaluate what combination of flags it is
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sample.flags = sample.flags
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return str(sample.flags) |