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