## 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
"""
ASN.1 (Abstract Syntax Notation One)
"""
import random
from scapy.config import conf
from scapy.error import Scapy_Exception,warning
from scapy.volatile import RandField
from scapy.utils import Enum_metaclass, EnumElement
class RandASN1Object(RandField):
def __init__(self, objlist=None):
if objlist is None:
objlist = map(lambda x:x._asn1_obj,
filter(lambda x:hasattr(x,"_asn1_obj"), ASN1_Class_UNIVERSAL.__rdict__.values()))
self.objlist = objlist
self.chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
def _fix(self, n=0):
o = random.choice(self.objlist)
if issubclass(o, ASN1_INTEGER):
return o(int(random.gauss(0,1000)))
elif issubclass(o, ASN1_IPADDRESS):
z = RandIP()._fix()
return o(z)
elif issubclass(o, ASN1_STRING):
z = int(random.expovariate(0.05)+1)
return o("".join([random.choice(self.chars) for i in range(z)]))
elif issubclass(o, ASN1_SEQUENCE) and (n < 10):
z = int(random.expovariate(0.08)+1)
return o(map(lambda x:x._fix(n+1), [self.__class__(objlist=self.objlist)]*z))
return ASN1_INTEGER(int(random.gauss(0,1000)))
##############
#### ASN1 ####
##############
class ASN1_Error(Scapy_Exception):
pass
class ASN1_Encoding_Error(ASN1_Error):
pass
class ASN1_Decoding_Error(ASN1_Error):
pass
class ASN1_BadTag_Decoding_Error(ASN1_Decoding_Error):
pass
class ASN1Codec(EnumElement):
def register_stem(cls, stem):
cls._stem = stem
def dec(cls, s, context=None):
return cls._stem.dec(s, context=context)
def safedec(cls, s, context=None):
return cls._stem.safedec(s, context=context)
def get_stem(cls):
return cls.stem
class ASN1_Codecs_metaclass(Enum_metaclass):
element_class = ASN1Codec
class ASN1_Codecs:
__metaclass__ = ASN1_Codecs_metaclass
BER = 1
DER = 2
PER = 3
CER = 4
LWER = 5
BACnet = 6
OER = 7
SER = 8
XER = 9
class ASN1Tag(EnumElement):
def __init__(self, key, value, context=None, codec=None):
EnumElement.__init__(self, key, value)
self._context = context
if codec == None:
codec = {}
self._codec = codec
def clone(self): # /!\ not a real deep copy. self.codec is shared
return self.__class__(self._key, self._value, self._context, self._codec)
def register_asn1_object(self, asn1obj):
self._asn1_obj = asn1obj
def asn1_object(self, val):
if hasattr(self,"_asn1_obj"):
return self._asn1_obj(val)
raise ASN1_Error("%r does not have any assigned ASN1 object" % self)
def register(self, codecnum, codec):
self._codec[codecnum] = codec
def get_codec(self, codec):
try:
c = self._codec[codec]
except KeyError,msg:
raise ASN1_Error("Codec %r not found for tag %r" % (codec, self))
return c
class ASN1_Class_metaclass(Enum_metaclass):
element_class = ASN1Tag
def __new__(cls, name, bases, dct): # XXX factorise a bit with Enum_metaclass.__new__()
for b in bases:
for k,v in b.__dict__.iteritems():
if k not in dct and isinstance(v,ASN1Tag):
dct[k] = v.clone()
rdict = {}
for k,v in dct.iteritems():
if type(v) is int:
v = ASN1Tag(k,v)
dct[k] = v
rdict[v] = v
elif isinstance(v, ASN1Tag):
rdict[v] = v
dct["__rdict__"] = rdict
cls = type.__new__(cls, name, bases, dct)
for v in cls.__dict__.values():
if isinstance(v, ASN1Tag):
v.context = cls # overwrite ASN1Tag contexts, even cloned ones
return cls
class ASN1_Class:
__metaclass__ = ASN1_Class_metaclass
class ASN1_Class_UNIVERSAL(ASN1_Class):
name = "UNIVERSAL"
ERROR = -3
RAW = -2
NONE = -1
ANY = 0
BOOLEAN = 1
INTEGER = 2
BIT_STRING = 3
STRING = 4
NULL = 5
OID = 6
OBJECT_DESCRIPTOR = 7
EXTERNAL = 8
REAL = 9
ENUMERATED = 10
EMBEDDED_PDF = 11
UTF8_STRING = 12
RELATIVE_OID = 13
SEQUENCE = 0x30#XXX 16 ??
SET = 0x31 #XXX 17 ??
NUMERIC_STRING = 18
PRINTABLE_STRING = 19
T61_STRING = 20
VIDEOTEX_STRING = 21
IA5_STRING = 22
UTC_TIME = 23
GENERALIZED_TIME = 24
GRAPHIC_STRING = 25
ISO646_STRING = 26
GENERAL_STRING = 27
UNIVERSAL_STRING = 28
CHAR_STRING = 29
BMP_STRING = 30
IPADDRESS = 0x40
COUNTER32 = 0x41
GAUGE32 = 0x42
TIME_TICKS = 0x43
SEP = 0x80
class ASN1_Object_metaclass(type):
def __new__(cls, name, bases, dct):
c = super(ASN1_Object_metaclass, cls).__new__(cls, name, bases, dct)
try:
c.tag.register_asn1_object(c)
except:
warning("Error registering %r for %r" % (c.tag, c.codec))
return c
class ASN1_Object:
__metaclass__ = ASN1_Object_metaclass
tag = ASN1_Class_UNIVERSAL.ANY
def __init__(self, val):
self.val = val
def enc(self, codec):
return self.tag.get_codec(codec).enc(self.val)
def __repr__(self):
return "<%s[%r]>" % (self.__dict__.get("name", self.__class__.__name__), self.val)
def __str__(self):
return self.enc(conf.ASN1_default_codec)
def strshow(self, lvl=0):
return (" "*lvl)+repr(self)+"\n"
def show(self, lvl=0):
print self.strshow(lvl)
def __eq__(self, other):
return self.val == other
def __cmp__(self, other):
return cmp(self.val, other)
class ASN1_DECODING_ERROR(ASN1_Object):
tag = ASN1_Class_UNIVERSAL.ERROR
def __init__(self, val, exc=None):
ASN1_Object.__init__(self, val)
self.exc = exc
def __repr__(self):
return "<%s[%r]{{%s}}>" % (self.__dict__.get("name", self.__class__.__name__),
self.val, self.exc.args[0])
def enc(self, codec):
if isinstance(self.val, ASN1_Object):
return self.val.enc(codec)
return self.val
class ASN1_force(ASN1_Object):
tag = ASN1_Class_UNIVERSAL.RAW
def enc(self, codec):
if isinstance(self.val, ASN1_Object):
return self.val.enc(codec)
return self.val
class ASN1_BADTAG(ASN1_force):
pass
class ASN1_INTEGER(ASN1_Object):
tag = ASN1_Class_UNIVERSAL.INTEGER
class ASN1_STRING(ASN1_Object):
tag = ASN1_Class_UNIVERSAL.STRING
class ASN1_BIT_STRING(ASN1_STRING):
tag = ASN1_Class_UNIVERSAL.BIT_STRING
class ASN1_PRINTABLE_STRING(ASN1_STRING):
tag = ASN1_Class_UNIVERSAL.PRINTABLE_STRING
class ASN1_T61_STRING(ASN1_STRING):
tag = ASN1_Class_UNIVERSAL.T61_STRING
class ASN1_IA5_STRING(ASN1_STRING):
tag = ASN1_Class_UNIVERSAL.IA5_STRING
class ASN1_NUMERIC_STRING(ASN1_STRING):
tag = ASN1_Class_UNIVERSAL.NUMERIC_STRING
class ASN1_VIDEOTEX_STRING(ASN1_STRING):
tag = ASN1_Class_UNIVERSAL.VIDEOTEX_STRING
class ASN1_IPADDRESS(ASN1_STRING):
tag = ASN1_Class_UNIVERSAL.IPADDRESS
class ASN1_UTC_TIME(ASN1_STRING):
tag = ASN1_Class_UNIVERSAL.UTC_TIME
class ASN1_GENERALIZED_TIME(ASN1_STRING):
tag = ASN1_Class_UNIVERSAL.GENERALIZED_TIME
class ASN1_TIME_TICKS(ASN1_INTEGER):
tag = ASN1_Class_UNIVERSAL.TIME_TICKS
class ASN1_BOOLEAN(ASN1_INTEGER):
tag = ASN1_Class_UNIVERSAL.BOOLEAN
class ASN1_ENUMERATED(ASN1_INTEGER):
tag = ASN1_Class_UNIVERSAL.ENUMERATED
class ASN1_NULL(ASN1_INTEGER):
tag = ASN1_Class_UNIVERSAL.NULL
class ASN1_SEP(ASN1_NULL):
tag = ASN1_Class_UNIVERSAL.SEP
class ASN1_GAUGE32(ASN1_INTEGER):
tag = ASN1_Class_UNIVERSAL.GAUGE32
class ASN1_COUNTER32(ASN1_INTEGER):
tag = ASN1_Class_UNIVERSAL.COUNTER32
class ASN1_SEQUENCE(ASN1_Object):
tag = ASN1_Class_UNIVERSAL.SEQUENCE
def strshow(self, lvl=0):
s = (" "*lvl)+("# %s:" % self.__class__.__name__)+"\n"
for o in self.val:
s += o.strshow(lvl=lvl+1)
return s
class ASN1_SET(ASN1_SEQUENCE):
tag = ASN1_Class_UNIVERSAL.SET
class ASN1_OID(ASN1_Object):
tag = ASN1_Class_UNIVERSAL.OID
def __init__(self, val):
val = conf.mib._oid(val)
ASN1_Object.__init__(self, val)
def __repr__(self):
return "<%s[%r]>" % (self.__dict__.get("name", self.__class__.__name__), conf.mib._oidname(self.val))
def __oidname__(self):
return '%s'%conf.mib._oidname(self.val)
conf.ASN1_default_codec = ASN1_Codecs.BER
