354 lines
14 KiB
Python
354 lines
14 KiB
Python
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# This file is part of Scapy
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# See http://www.secdev.org/projects/scapy for more information
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# Copyright (C) Philippe Biondi <phil@secdev.org>
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# This program is published under a GPLv2 license
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"""
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ISAKMP (Internet Security Association and Key Management Protocol).
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"""
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# Mostly based on https://tools.ietf.org/html/rfc2408
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from __future__ import absolute_import
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import struct
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from scapy.config import conf
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from scapy.packet import Packet, bind_bottom_up, bind_top_down, bind_layers
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from scapy.compat import chb
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from scapy.fields import ByteEnumField, ByteField, FieldLenField, FlagsField, \
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IntEnumField, IntField, PacketLenField, ShortEnumField, ShortField, \
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StrFixedLenField, StrLenField, XByteField
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from scapy.layers.inet import IP, UDP
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from scapy.sendrecv import sr
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from scapy.volatile import RandString
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from scapy.error import warning
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from functools import reduce
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# TODO: some ISAKMP payloads are not implemented,
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# and inherit a default ISAKMP_payload
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# see http://www.iana.org/assignments/ipsec-registry for details
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ISAKMPAttributeTypes = {"Encryption": (1, {"DES-CBC": 1,
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"IDEA-CBC": 2,
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"Blowfish-CBC": 3,
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"RC5-R16-B64-CBC": 4,
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"3DES-CBC": 5,
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"CAST-CBC": 6,
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"AES-CBC": 7,
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"CAMELLIA-CBC": 8, }, 0),
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"Hash": (2, {"MD5": 1,
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"SHA": 2,
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"Tiger": 3,
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"SHA2-256": 4,
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"SHA2-384": 5,
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"SHA2-512": 6, }, 0),
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"Authentication": (3, {"PSK": 1,
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"DSS": 2,
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"RSA Sig": 3,
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"RSA Encryption": 4,
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"RSA Encryption Revised": 5,
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"ElGamal Encryption": 6,
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"ElGamal Encryption Revised": 7,
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"ECDSA Sig": 8,
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"HybridInitRSA": 64221,
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"HybridRespRSA": 64222,
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"HybridInitDSS": 64223,
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"HybridRespDSS": 64224,
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"XAUTHInitPreShared": 65001,
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"XAUTHRespPreShared": 65002,
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"XAUTHInitDSS": 65003,
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"XAUTHRespDSS": 65004,
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"XAUTHInitRSA": 65005,
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"XAUTHRespRSA": 65006,
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"XAUTHInitRSAEncryption": 65007,
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"XAUTHRespRSAEncryption": 65008,
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"XAUTHInitRSARevisedEncryption": 65009, # noqa: E501
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"XAUTHRespRSARevisedEncryptio": 65010, }, 0), # noqa: E501
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"GroupDesc": (4, {"768MODPgr": 1,
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"1024MODPgr": 2,
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"EC2Ngr155": 3,
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"EC2Ngr185": 4,
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"1536MODPgr": 5,
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"2048MODPgr": 14,
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"3072MODPgr": 15,
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"4096MODPgr": 16,
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"6144MODPgr": 17,
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"8192MODPgr": 18, }, 0),
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"GroupType": (5, {"MODP": 1,
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"ECP": 2,
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"EC2N": 3}, 0),
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"GroupPrime": (6, {}, 1),
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"GroupGenerator1": (7, {}, 1),
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"GroupGenerator2": (8, {}, 1),
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"GroupCurveA": (9, {}, 1),
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"GroupCurveB": (10, {}, 1),
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"LifeType": (11, {"Seconds": 1,
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"Kilobytes": 2}, 0),
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"LifeDuration": (12, {}, 1),
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"PRF": (13, {}, 0),
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"KeyLength": (14, {}, 0),
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"FieldSize": (15, {}, 0),
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"GroupOrder": (16, {}, 1),
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}
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# the name 'ISAKMPTransformTypes' is actually a misnomer (since the table
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# holds info for all ISAKMP Attribute types, not just transforms, but we'll
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# keep it for backwards compatibility... for now at least
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ISAKMPTransformTypes = ISAKMPAttributeTypes
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ISAKMPTransformNum = {}
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for n in ISAKMPTransformTypes:
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val = ISAKMPTransformTypes[n]
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tmp = {}
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for e in val[1]:
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tmp[val[1][e]] = e
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ISAKMPTransformNum[val[0]] = (n, tmp, val[2])
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del(n)
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del(e)
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del(tmp)
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del(val)
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class ISAKMPTransformSetField(StrLenField):
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islist = 1
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@staticmethod
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def type2num(type_val_tuple):
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typ, val = type_val_tuple
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type_val, enc_dict, tlv = ISAKMPTransformTypes.get(typ, (typ, {}, 0))
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val = enc_dict.get(val, val)
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s = b""
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if (val & ~0xffff):
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if not tlv:
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warning("%r should not be TLV but is too big => using TLV encoding" % typ) # noqa: E501
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n = 0
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while val:
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s = chb(val & 0xff) + s
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val >>= 8
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n += 1
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val = n
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else:
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type_val |= 0x8000
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return struct.pack("!HH", type_val, val) + s
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@staticmethod
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def num2type(typ, enc):
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val = ISAKMPTransformNum.get(typ, (typ, {}))
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enc = val[1].get(enc, enc)
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return (val[0], enc)
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def i2m(self, pkt, i):
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if i is None:
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return b""
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i = [ISAKMPTransformSetField.type2num(e) for e in i]
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return b"".join(i)
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def m2i(self, pkt, m):
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# I try to ensure that we don't read off the end of our packet based
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# on bad length fields we're provided in the packet. There are still
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# conditions where struct.unpack() may not get enough packet data, but
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# worst case that should result in broken attributes (which would
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# be expected). (wam)
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lst = []
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while len(m) >= 4:
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trans_type, = struct.unpack("!H", m[:2])
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is_tlv = not (trans_type & 0x8000)
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if is_tlv:
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# We should probably check to make sure the attribute type we
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# are looking at is allowed to have a TLV format and issue a
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# warning if we're given an TLV on a basic attribute.
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value_len, = struct.unpack("!H", m[2:4])
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if value_len + 4 > len(m):
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warning("Bad length for ISAKMP transform type=%#6x" % trans_type) # noqa: E501
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value = m[4:4 + value_len]
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value = reduce(lambda x, y: (x << 8) | y, struct.unpack("!%s" % ("B" * len(value),), value), 0) # noqa: E501
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else:
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trans_type &= 0x7fff
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value_len = 0
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value, = struct.unpack("!H", m[2:4])
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m = m[4 + value_len:]
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lst.append(ISAKMPTransformSetField.num2type(trans_type, value))
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if len(m) > 0:
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warning("Extra bytes after ISAKMP transform dissection [%r]" % m)
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return lst
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ISAKMP_payload_type = ["None", "SA", "Proposal", "Transform", "KE", "ID",
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"CERT", "CR", "Hash", "SIG", "Nonce", "Notification",
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"Delete", "VendorID"]
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ISAKMP_exchange_type = ["None", "base", "identity prot.",
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"auth only", "aggressive", "info"]
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class ISAKMP_class(Packet):
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def guess_payload_class(self, payload):
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np = self.next_payload
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if np == 0:
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return conf.raw_layer
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elif np < len(ISAKMP_payload_type):
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pt = ISAKMP_payload_type[np]
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return globals().get("ISAKMP_payload_%s" % pt, ISAKMP_payload)
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else:
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return ISAKMP_payload
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class ISAKMP(ISAKMP_class): # rfc2408
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name = "ISAKMP"
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fields_desc = [
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StrFixedLenField("init_cookie", "", 8),
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StrFixedLenField("resp_cookie", "", 8),
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ByteEnumField("next_payload", 0, ISAKMP_payload_type),
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XByteField("version", 0x10),
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ByteEnumField("exch_type", 0, ISAKMP_exchange_type),
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FlagsField("flags", 0, 8, ["encryption", "commit", "auth_only", "res3", "res4", "res5", "res6", "res7"]), # XXX use a Flag field # noqa: E501
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IntField("id", 0),
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IntField("length", None)
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]
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def guess_payload_class(self, payload):
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if self.flags & 1:
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return conf.raw_layer
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return ISAKMP_class.guess_payload_class(self, payload)
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def answers(self, other):
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if isinstance(other, ISAKMP):
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if other.init_cookie == self.init_cookie:
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return 1
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return 0
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def post_build(self, p, pay):
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p += pay
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if self.length is None:
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p = p[:24] + struct.pack("!I", len(p)) + p[28:]
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return p
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class ISAKMP_payload_Transform(ISAKMP_class):
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name = "IKE Transform"
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fields_desc = [
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ByteEnumField("next_payload", None, ISAKMP_payload_type),
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ByteField("res", 0),
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# ShortField("len",None),
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ShortField("length", None),
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ByteField("num", None),
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ByteEnumField("id", 1, {1: "KEY_IKE"}),
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ShortField("res2", 0),
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ISAKMPTransformSetField("transforms", None, length_from=lambda x: x.length - 8) # noqa: E501
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# XIntField("enc",0x80010005L),
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# XIntField("hash",0x80020002L),
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# XIntField("auth",0x80030001L),
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# XIntField("group",0x80040002L),
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# XIntField("life_type",0x800b0001L),
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# XIntField("durationh",0x000c0004L),
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# XIntField("durationl",0x00007080L),
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]
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def post_build(self, p, pay):
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if self.length is None:
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tmp_len = len(p)
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tmp_pay = p[:2] + chb((tmp_len >> 8) & 0xff)
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p = tmp_pay + chb(tmp_len & 0xff) + p[4:]
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p += pay
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return p
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# https://tools.ietf.org/html/rfc2408#section-3.5
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class ISAKMP_payload_Proposal(ISAKMP_class):
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name = "IKE proposal"
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# ISAKMP_payload_type = 0
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fields_desc = [
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ByteEnumField("next_payload", None, ISAKMP_payload_type),
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ByteField("res", 0),
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FieldLenField("length", None, "trans", "H", adjust=lambda pkt, x:x + 8), # noqa: E501
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ByteField("proposal", 1),
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ByteEnumField("proto", 1, {1: "ISAKMP"}),
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FieldLenField("SPIsize", None, "SPI", "B"),
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ByteField("trans_nb", None),
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StrLenField("SPI", "", length_from=lambda x: x.SPIsize),
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PacketLenField("trans", conf.raw_layer(), ISAKMP_payload_Transform, length_from=lambda x: x.length - 8), # noqa: E501
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]
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class ISAKMP_payload(ISAKMP_class):
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name = "ISAKMP payload"
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fields_desc = [
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ByteEnumField("next_payload", None, ISAKMP_payload_type),
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ByteField("res", 0),
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FieldLenField("length", None, "load", "H", adjust=lambda pkt, x:x + 4),
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StrLenField("load", "", length_from=lambda x:x.length - 4),
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]
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class ISAKMP_payload_VendorID(ISAKMP_payload):
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name = "ISAKMP Vendor ID"
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class ISAKMP_payload_SA(ISAKMP_class):
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name = "ISAKMP SA"
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fields_desc = [
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ByteEnumField("next_payload", None, ISAKMP_payload_type),
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ByteField("res", 0),
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FieldLenField("length", None, "prop", "H", adjust=lambda pkt, x:x + 12), # noqa: E501
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IntEnumField("DOI", 1, {1: "IPSEC"}),
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IntEnumField("situation", 1, {1: "identity"}),
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PacketLenField("prop", conf.raw_layer(), ISAKMP_payload_Proposal, length_from=lambda x: x.length - 12), # noqa: E501
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]
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class ISAKMP_payload_Nonce(ISAKMP_payload):
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name = "ISAKMP Nonce"
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class ISAKMP_payload_KE(ISAKMP_payload):
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name = "ISAKMP Key Exchange"
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class ISAKMP_payload_ID(ISAKMP_class):
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name = "ISAKMP Identification"
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fields_desc = [
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ByteEnumField("next_payload", None, ISAKMP_payload_type),
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ByteField("res", 0),
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FieldLenField("length", None, "load", "H", adjust=lambda pkt, x:x + 8),
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ByteEnumField("IDtype", 1, {1: "IPv4_addr", 11: "Key"}),
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ByteEnumField("ProtoID", 0, {0: "Unused"}),
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ShortEnumField("Port", 0, {0: "Unused"}),
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# IPField("IdentData","127.0.0.1"),
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StrLenField("load", "", length_from=lambda x: x.length - 8),
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]
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class ISAKMP_payload_Hash(ISAKMP_payload):
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name = "ISAKMP Hash"
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bind_bottom_up(UDP, ISAKMP, dport=500)
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bind_bottom_up(UDP, ISAKMP, sport=500)
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bind_layers(UDP, ISAKMP, dport=500, sport=500)
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# Add building bindings
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# (Dissection bindings are located in ISAKMP_class.guess_payload_class)
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bind_top_down(ISAKMP_class, ISAKMP_payload, next_payload=0)
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bind_top_down(ISAKMP_class, ISAKMP_payload_SA, next_payload=1)
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bind_top_down(ISAKMP_class, ISAKMP_payload_Proposal, next_payload=2)
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bind_top_down(ISAKMP_class, ISAKMP_payload_Transform, next_payload=3)
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bind_top_down(ISAKMP_class, ISAKMP_payload_KE, next_payload=4)
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bind_top_down(ISAKMP_class, ISAKMP_payload_ID, next_payload=5)
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# bind_top_down(ISAKMP_class, ISAKMP_payload_CERT, next_payload=6)
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# bind_top_down(ISAKMP_class, ISAKMP_payload_CR, next_payload=7)
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bind_top_down(ISAKMP_class, ISAKMP_payload_Hash, next_payload=8)
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# bind_top_down(ISAKMP_class, ISAKMP_payload_SIG, next_payload=9)
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||
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bind_top_down(ISAKMP_class, ISAKMP_payload_Nonce, next_payload=10)
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||
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# bind_top_down(ISAKMP_class, ISAKMP_payload_Notification, next_payload=11)
|
||
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# bind_top_down(ISAKMP_class, ISAKMP_payload_Delete, next_payload=12)
|
||
|
|
bind_top_down(ISAKMP_class, ISAKMP_payload_VendorID, next_payload=13)
|
||
|
|
|
||
|
|
|
||
|
|
def ikescan(ip):
|
||
|
|
"""Sends/receives a ISAMPK payload SA with payload proposal"""
|
||
|
|
pkt = IP(dst=ip)
|
||
|
|
pkt /= UDP()
|
||
|
|
pkt /= ISAKMP(init_cookie=RandString(8), exch_type=2)
|
||
|
|
pkt /= ISAKMP_payload_SA(prop=ISAKMP_payload_Proposal())
|
||
|
|
return sr(pkt)
|