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#!/usr/bin/env python
# http://trac.secdev.org/scapy/ticket/353
# scapy.contrib.description = IKEv2
# scapy.contrib.status = loads
from scapy.all import *
import logging
## Modified from the original ISAKMP code by Yaron Sheffer <yaronf.ietf@gmail.com>, June 2010.
import struct
from scapy.packet import *
from scapy.fields import *
from scapy.ansmachine import *
from scapy.layers.inet import IP,UDP
from scapy.sendrecv import sr
# see http://www.iana.org/assignments/ikev2-parameters for details
IKEv2AttributeTypes= { "Encryption": (1, { "DES-IV64" : 1,
"DES" : 2,
"3DES" : 3,
"RC5" : 4,
"IDEA" : 5,
"CAST" : 6,
"Blowfish" : 7,
"3IDEA" : 8,
"DES-IV32" : 9,
"AES-CBC" : 12,
"AES-CTR" : 13,
"AES-CCM-8" : 14,
"AES-CCM-12" : 15,
"AES-CCM-16" : 16,
"AES-GCM-8ICV" : 18,
"AES-GCM-12ICV" : 19,
"AES-GCM-16ICV" : 20,
"Camellia-CBC" : 23,
"Camellia-CTR" : 24,
"Camellia-CCM-8ICV" : 25,
"Camellia-CCM-12ICV" : 26,
"Camellia-CCM-16ICV" : 27,
}, 0),
"PRF": (2, {"PRF_HMAC_MD5":1,
"PRF_HMAC_SHA1":2,
"PRF_HMAC_TIGER":3,
"PRF_AES128_XCBC":4,
"PRF_HMAC_SHA2_256":5,
"PRF_HMAC_SHA2_384":6,
"PRF_HMAC_SHA2_512":7,
"PRF_AES128_CMAC":8,
}, 0),
"Integrity": (3, { "HMAC-MD5-96": 1,
"HMAC-SHA1-96": 2,
"DES-MAC": 3,
"KPDK-MD5": 4,
"AES-XCBC-96": 5,
"HMAC-MD5-128": 6,
"HMAC-SHA1-160": 7,
"AES-CMAC-96": 8,
"AES-128-GMAC": 9,
"AES-192-GMAC": 10,
"AES-256-GMAC": 11,
"SHA2-256-128": 12,
"SHA2-384-192": 13,
"SHA2-512-256": 14,
}, 0),
"GroupDesc": (4, { "768MODPgr" : 1,
"1024MODPgr" : 2,
"1536MODPgr" : 5,
"2048MODPgr" : 14,
"3072MODPgr" : 15,
"4096MODPgr" : 16,
"6144MODPgr" : 17,
"8192MODPgr" : 18,
"256randECPgr" : 19,
"384randECPgr" : 20,
"521randECPgr" : 21,
"1024MODP160POSgr" : 22,
"2048MODP224POSgr" : 23,
"2048MODP256POSgr" : 24,
"192randECPgr" : 25,
"224randECPgr" : 26,
}, 0),
"Extended Sequence Number": (5, {"No ESN": 0,
"ESN": 1, }, 0),
}
# the name 'IKEv2TransformTypes' is actually a misnomer (since the table
# holds info for all IKEv2 Attribute types, not just transforms, but we'll
# keep it for backwards compatibility... for now at least
IKEv2TransformTypes = IKEv2AttributeTypes
IKEv2TransformNum = {}
for n in IKEv2TransformTypes:
val = IKEv2TransformTypes[n]
tmp = {}
for e in val[1]:
tmp[val[1][e]] = e
IKEv2TransformNum[val[0]] = (n,tmp, val[2])
IKEv2Transforms = {}
for n in IKEv2TransformTypes:
IKEv2Transforms[IKEv2TransformTypes[n][0]]=n
del(n)
del(e)
del(tmp)
del(val)
# Note: Transform and Proposal can only be used inside the SA payload
IKEv2_payload_type = ["None", "", "Proposal", "Transform"]
IKEv2_payload_type.extend([""] * 29)
IKEv2_payload_type.extend(["SA","KE","IDi","IDr", "CERT","CERTREQ","AUTH","Nonce","Notify","Delete",
"VendorID","TSi","TSr","Encrypted","CP","EAP"])
IKEv2_exchange_type = [""] * 34
IKEv2_exchange_type.extend(["IKE_SA_INIT","IKE_AUTH","CREATE_CHILD_SA",
"INFORMATIONAL", "IKE_SESSION_RESUME"])
class IKEv2_class(Packet):
def guess_payload_class(self, payload):
np = self.next_payload
logging.debug("For IKEv2_class np=%d" % np)
if np == 0:
return conf.raw_layer
elif np < len(IKEv2_payload_type):
pt = IKEv2_payload_type[np]
logging.debug(globals().get("IKEv2_payload_%s" % pt, IKEv2_payload))
return globals().get("IKEv2_payload_%s" % pt, IKEv2_payload)
else:
return IKEv2_payload
class IKEv2(IKEv2_class): # rfc4306
name = "IKEv2"
fields_desc = [
StrFixedLenField("init_SPI","",8),
StrFixedLenField("resp_SPI","",8),
ByteEnumField("next_payload",0,IKEv2_payload_type),
XByteField("version",0x20), # IKEv2, right?
ByteEnumField("exch_type",0,IKEv2_exchange_type),
FlagsField("flags",0, 8, ["res0","res1","res2","Initiator","Version","Response","res6","res7"]),
IntField("id",0),
IntField("length",None)
]
def guess_payload_class(self, payload):
if self.flags & 1:
return conf.raw_layer
return IKEv2_class.guess_payload_class(self, payload)
def answers(self, other):
if isinstance(other, IKEv2):
if other.init_SPI == self.init_SPI:
return 1
return 0
def post_build(self, p, pay):
p += pay
if self.length is None:
p = p[:24]+struct.pack("!I",len(p))+p[28:]
return p
class IKEv2_Key_Length_Attribute(IntField):
# We only support the fixed-length Key Length attribute (the only one currently defined)
name="key length"
def __init__(self, name):
IntField.__init__(self, name, "0x800E0000")
def i2h(self, pkt, x):
return IntField.i2h(self, pkt, x & 0xFFFF)
def h2i(self, pkt, x):
return IntField.h2i(self, pkt, struct.pack("!I", 0x800E0000 | int(x, 0)))
class IKEv2_Transform_ID(ShortField):
def i2h(self, pkt, x):
if pkt == None:
return None
else:
map = IKEv2TransformNum[pkt.transform_type][1]
return map[x]
def h2i(self, pkt, x):
if pkt == None:
return None
else:
map = IKEv2TransformNum[pkt.transform_type][1]
for k in keys(map):
if map[k] == x:
return k
return None
class IKEv2_payload_Transform(IKEv2_class):
name = "IKE Transform"
fields_desc = [
ByteEnumField("next_payload",None,{0:"last", 3:"Transform"}),
ByteField("res",0),
ShortField("length",8),
ByteEnumField("transform_type",None,IKEv2Transforms),
ByteField("res2",0),
IKEv2_Transform_ID("transform_id", 0),
ConditionalField(IKEv2_Key_Length_Attribute("key_length"), lambda pkt: pkt.length > 8),
]
class IKEv2_payload_Proposal(IKEv2_class):
name = "IKEv2 Proposal"
fields_desc = [
ByteEnumField("next_payload",None,{0:"last", 2:"Proposal"}),
ByteField("res",0),
FieldLenField("length",None,"trans","H", adjust=lambda pkt,x:x+8),
ByteField("proposal",1),
ByteEnumField("proto",1,{1:"IKEv2"}),
FieldLenField("SPIsize",None,"SPI","B"),
ByteField("trans_nb",None),
StrLenField("SPI","",length_from=lambda x:x.SPIsize),
PacketLenField("trans",conf.raw_layer(),IKEv2_payload_Transform,length_from=lambda x:x.length-8),
]
class IKEv2_payload(IKEv2_class):
name = "IKEv2 Payload"
fields_desc = [
ByteEnumField("next_payload",None,IKEv2_payload_type),
FlagsField("flags",0, 8, ["critical","res1","res2","res3","res4","res5","res6","res7"]),
FieldLenField("length",None,"load","H", adjust=lambda pkt,x:x+4),
StrLenField("load","",length_from=lambda x:x.length-4),
]
class IKEv2_payload_VendorID(IKEv2_class):
name = "IKEv2 Vendor ID"
overload_fields = { IKEv2: { "next_payload":43 }}
fields_desc = [
ByteEnumField("next_payload",None,IKEv2_payload_type),
ByteField("res",0),
FieldLenField("length",None,"vendorID","H", adjust=lambda pkt,x:x+4),
StrLenField("vendorID","",length_from=lambda x:x.length-4),
]
class IKEv2_payload_Delete(IKEv2_class):
name = "IKEv2 Vendor ID"
overload_fields = { IKEv2: { "next_payload":42 }}
fields_desc = [
ByteEnumField("next_payload",None,IKEv2_payload_type),
ByteField("res",0),
FieldLenField("length",None,"vendorID","H", adjust=lambda pkt,x:x+4),
StrLenField("vendorID","",length_from=lambda x:x.length-4),
]
class IKEv2_payload_SA(IKEv2_class):
name = "IKEv2 SA"
overload_fields = { IKEv2: { "next_payload":33 }}
fields_desc = [
ByteEnumField("next_payload",None,IKEv2_payload_type),
ByteField("res",0),
FieldLenField("length",None,"prop","H", adjust=lambda pkt,x:x+4),
PacketLenField("prop",conf.raw_layer(),IKEv2_payload_Proposal,length_from=lambda x:x.length-4),
]
class IKEv2_payload_Nonce(IKEv2_class):
name = "IKEv2 Nonce"
overload_fields = { IKEv2: { "next_payload":40 }}
fields_desc = [
ByteEnumField("next_payload",None,IKEv2_payload_type),
ByteField("res",0),
FieldLenField("length",None,"load","H", adjust=lambda pkt,x:x+4),
StrLenField("load","",length_from=lambda x:x.length-4),
]
class IKEv2_payload_Notify(IKEv2_class):
name = "IKEv2 Notify"
overload_fields = { IKEv2: { "next_payload":41 }}
fields_desc = [
ByteEnumField("next_payload",None,IKEv2_payload_type),
ByteField("res",0),
FieldLenField("length",None,"load","H", adjust=lambda pkt,x:x+4),
StrLenField("load","",length_from=lambda x:x.length-4),
]
class IKEv2_payload_KE(IKEv2_class):
name = "IKEv2 Key Exchange"
overload_fields = { IKEv2: { "next_payload":34 }}
fields_desc = [
ByteEnumField("next_payload",None,IKEv2_payload_type),
ByteField("res",0),
FieldLenField("length",None,"load","H", adjust=lambda pkt,x:x+6),
ShortEnumField("group", 0, IKEv2TransformTypes['GroupDesc'][1]),
StrLenField("load","",length_from=lambda x:x.length-6),
]
class IKEv2_payload_IDi(IKEv2_class):
name = "IKEv2 Identification - Initiator"
overload_fields = { IKEv2: { "next_payload":35 }}
fields_desc = [
ByteEnumField("next_payload",None,IKEv2_payload_type),
ByteField("res",0),
FieldLenField("length",None,"load","H",adjust=lambda pkt,x:x+8),
ByteEnumField("IDtype",1,{1:"IPv4_addr", 11:"Key"}),
ByteEnumField("ProtoID",0,{0:"Unused"}),
ShortEnumField("Port",0,{0:"Unused"}),
# IPField("IdentData","127.0.0.1"),
StrLenField("load","",length_from=lambda x:x.length-8),
]
class IKEv2_payload_IDr(IKEv2_class):
name = "IKEv2 Identification - Responder"
overload_fields = { IKEv2: { "next_payload":36 }}
fields_desc = [
ByteEnumField("next_payload",None,IKEv2_payload_type),
ByteField("res",0),
FieldLenField("length",None,"load","H",adjust=lambda pkt,x:x+8),
ByteEnumField("IDtype",1,{1:"IPv4_addr", 11:"Key"}),
ByteEnumField("ProtoID",0,{0:"Unused"}),
ShortEnumField("Port",0,{0:"Unused"}),
# IPField("IdentData","127.0.0.1"),
StrLenField("load","",length_from=lambda x:x.length-8),
]
class IKEv2_payload_Encrypted(IKEv2_class):
name = "IKEv2 Encrypted and Authenticated"
overload_fields = { IKEv2: { "next_payload":46 }}
fields_desc = [
ByteEnumField("next_payload",None,IKEv2_payload_type),
ByteField("res",0),
FieldLenField("length",None,"load","H",adjust=lambda pkt,x:x+4),
StrLenField("load","",length_from=lambda x:x.length-4),
]
IKEv2_payload_type_overload = {}
for i in range(len(IKEv2_payload_type)):
name = "IKEv2_payload_%s" % IKEv2_payload_type[i]
if name in globals():
IKEv2_payload_type_overload[globals()[name]] = {"next_payload":i}
del(i)
del(name)
IKEv2_class.overload_fields = IKEv2_payload_type_overload.copy()
split_layers(UDP, ISAKMP, sport=500)
split_layers(UDP, ISAKMP, dport=500)
bind_layers( UDP, IKEv2, dport=500, sport=500) # TODO: distinguish IKEv1/IKEv2
bind_layers( UDP, IKEv2, dport=4500, sport=4500)
def ikev2scan(ip):
return sr(IP(dst=ip)/UDP()/IKEv2(init_SPI=RandString(8),
exch_type=34)/IKEv2_payload_SA(prop=IKEv2_payload_Proposal()))
# conf.debug_dissector = 1
if __name__ == "__main__":
interact(mydict=globals(), mybanner="IKEv2 alpha-level protocol implementation")
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