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Diffstat (limited to 'scripts/external_libs/scapy-2.3.1/python2/scapy/asn1/ber.py')
| -rw-r--r-- | scripts/external_libs/scapy-2.3.1/python2/scapy/asn1/ber.py | 363 |
1 files changed, 363 insertions, 0 deletions
diff --git a/scripts/external_libs/scapy-2.3.1/python2/scapy/asn1/ber.py b/scripts/external_libs/scapy-2.3.1/python2/scapy/asn1/ber.py new file mode 100644 index 00000000..2312e025 --- /dev/null +++ b/scripts/external_libs/scapy-2.3.1/python2/scapy/asn1/ber.py @@ -0,0 +1,363 @@ +## 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 + +""" +Basic Encoding Rules (BER) for ASN.1 +""" + +from scapy.error import warning +from scapy.utils import inet_aton,inet_ntoa +from asn1 import ASN1_Decoding_Error,ASN1_Encoding_Error,ASN1_BadTag_Decoding_Error,ASN1_Codecs,ASN1_Class_UNIVERSAL,ASN1_Error,ASN1_DECODING_ERROR,ASN1_BADTAG + +################## +## BER encoding ## +################## + + + +#####[ BER tools ]##### + + +class BER_Exception(Exception): + pass + +class BER_Encoding_Error(ASN1_Encoding_Error): + def __init__(self, msg, encoded=None, remaining=None): + Exception.__init__(self, msg) + self.remaining = remaining + self.encoded = encoded + def __str__(self): + s = Exception.__str__(self) + if isinstance(self.encoded, BERcodec_Object): + s+="\n### Already encoded ###\n%s" % self.encoded.strshow() + else: + s+="\n### Already encoded ###\n%r" % self.encoded + s+="\n### Remaining ###\n%r" % self.remaining + return s + +class BER_Decoding_Error(ASN1_Decoding_Error): + def __init__(self, msg, decoded=None, remaining=None): + Exception.__init__(self, msg) + self.remaining = remaining + self.decoded = decoded + def __str__(self): + s = Exception.__str__(self) + if isinstance(self.decoded, BERcodec_Object): + s+="\n### Already decoded ###\n%s" % self.decoded.strshow() + else: + s+="\n### Already decoded ###\n%r" % self.decoded + s+="\n### Remaining ###\n%r" % self.remaining + return s + +class BER_BadTag_Decoding_Error(BER_Decoding_Error, ASN1_BadTag_Decoding_Error): + pass + +def BER_len_enc(l, size=0): + if l <= 127 and size==0: + return chr(l) + s = "" + while l or size>0: + s = chr(l&0xff)+s + l >>= 8L + size -= 1 + if len(s) > 127: + raise BER_Exception("BER_len_enc: Length too long (%i) to be encoded [%r]" % (len(s),s)) + return chr(len(s)|0x80)+s +def BER_len_dec(s): + l = ord(s[0]) + if not l & 0x80: + return l,s[1:] + l &= 0x7f + if len(s) <= l: + raise BER_Decoding_Error("BER_len_dec: Got %i bytes while expecting %i" % (len(s)-1, l),remaining=s) + ll = 0L + for c in s[1:l+1]: + ll <<= 8L + ll |= ord(c) + return ll,s[l+1:] + +def BER_num_enc(l, size=1): + x=[] + while l or size>0: + x.insert(0, l & 0x7f) + if len(x) > 1: + x[0] |= 0x80 + l >>= 7 + size -= 1 + return "".join([chr(k) for k in x]) +def BER_num_dec(s): + x = 0 + for i in range(len(s)): + c = ord(s[i]) + x <<= 7 + x |= c&0x7f + if not c&0x80: + break + if c&0x80: + raise BER_Decoding_Error("BER_num_dec: unfinished number description", remaining=s) + return x, s[i+1:] + +#####[ BER classes ]##### + +class BERcodec_metaclass(type): + def __new__(cls, name, bases, dct): + c = super(BERcodec_metaclass, cls).__new__(cls, name, bases, dct) + try: + c.tag.register(c.codec, c) + except: + warning("Error registering %r for %r" % (c.tag, c.codec)) + return c + + +class BERcodec_Object: + __metaclass__ = BERcodec_metaclass + codec = ASN1_Codecs.BER + tag = ASN1_Class_UNIVERSAL.ANY + + @classmethod + def asn1_object(cls, val): + return cls.tag.asn1_object(val) + + @classmethod + def check_string(cls, s): + if not s: + raise BER_Decoding_Error("%s: Got empty object while expecting tag %r" % + (cls.__name__,cls.tag), remaining=s) + @classmethod + def check_type(cls, s): + cls.check_string(s) + if cls.tag != ord(s[0]): + raise BER_BadTag_Decoding_Error("%s: Got tag [%i/%#x] while expecting %r" % + (cls.__name__, ord(s[0]), ord(s[0]),cls.tag), remaining=s) + return s[1:] + @classmethod + def check_type_get_len(cls, s): + s2 = cls.check_type(s) + if not s2: + raise BER_Decoding_Error("%s: No bytes while expecting a length" % + cls.__name__, remaining=s) + return BER_len_dec(s2) + @classmethod + def check_type_check_len(cls, s): + l,s3 = cls.check_type_get_len(s) + if len(s3) < l: + raise BER_Decoding_Error("%s: Got %i bytes while expecting %i" % + (cls.__name__, len(s3), l), remaining=s) + return l,s3[:l],s3[l:] + + @classmethod + def do_dec(cls, s, context=None, safe=False): + if context is None: + context = cls.tag.context + cls.check_string(s) + p = ord(s[0]) + if p not in context: + t = s + if len(t) > 18: + t = t[:15]+"..." + raise BER_Decoding_Error("Unknown prefix [%02x] for [%r]" % (p,t), remaining=s) + codec = context[p].get_codec(ASN1_Codecs.BER) + return codec.dec(s,context,safe) + + @classmethod + def dec(cls, s, context=None, safe=False): + if not safe: + return cls.do_dec(s, context, safe) + try: + return cls.do_dec(s, context, safe) + except BER_BadTag_Decoding_Error,e: + o,remain = BERcodec_Object.dec(e.remaining, context, safe) + return ASN1_BADTAG(o),remain + except BER_Decoding_Error, e: + return ASN1_DECODING_ERROR(s, exc=e),"" + except ASN1_Error, e: + return ASN1_DECODING_ERROR(s, exc=e),"" + + @classmethod + def safedec(cls, s, context=None): + return cls.dec(s, context, safe=True) + + + @classmethod + def enc(cls, s): + if type(s) is str: + return BERcodec_STRING.enc(s) + else: + return BERcodec_INTEGER.enc(int(s)) + + + +ASN1_Codecs.BER.register_stem(BERcodec_Object) + + +class BERcodec_INTEGER(BERcodec_Object): + tag = ASN1_Class_UNIVERSAL.INTEGER + @classmethod + def enc(cls, i): + s = [] + while 1: + s.append(i&0xff) + if -127 <= i < 0: + break + if 128 <= i <= 255: + s.append(0) + i >>= 8 + if not i: + break + s = map(chr, s) + s.append(BER_len_enc(len(s))) + s.append(chr(cls.tag)) + s.reverse() + return "".join(s) + @classmethod + def do_dec(cls, s, context=None, safe=False): + l,s,t = cls.check_type_check_len(s) + x = 0L + if s: + if ord(s[0])&0x80: # negative int + x = -1L + for c in s: + x <<= 8 + x |= ord(c) + return cls.asn1_object(x),t + + +class BERcodec_BOOLEAN(BERcodec_INTEGER): + tag = ASN1_Class_UNIVERSAL.BOOLEAN + +class BERcodec_ENUMERATED(BERcodec_INTEGER): + tag = ASN1_Class_UNIVERSAL.ENUMERATED + +class BERcodec_NULL(BERcodec_INTEGER): + tag = ASN1_Class_UNIVERSAL.NULL + @classmethod + def enc(cls, i): + if i == 0: + return chr(cls.tag)+"\0" + else: + return BERcodec_INTEGER.enc(i) + +class BERcodec_SEP(BERcodec_NULL): + tag = ASN1_Class_UNIVERSAL.SEP + +class BERcodec_STRING(BERcodec_Object): + tag = ASN1_Class_UNIVERSAL.STRING + @classmethod + def enc(cls,s): + return chr(cls.tag)+BER_len_enc(len(s))+s + @classmethod + def do_dec(cls, s, context=None, safe=False): + l,s,t = cls.check_type_check_len(s) + return cls.tag.asn1_object(s),t + +class BERcodec_BIT_STRING(BERcodec_STRING): + tag = ASN1_Class_UNIVERSAL.BIT_STRING + +class BERcodec_PRINTABLE_STRING(BERcodec_STRING): + tag = ASN1_Class_UNIVERSAL.PRINTABLE_STRING + +class BERcodec_T61_STRING (BERcodec_STRING): + tag = ASN1_Class_UNIVERSAL.T61_STRING + +class BERcodec_IA5_STRING(BERcodec_STRING): + tag = ASN1_Class_UNIVERSAL.IA5_STRING + +class BERcodec_NUMERIC_STRING(BERcodec_STRING): + tag = ASN1_Class_UNIVERSAL.NUMERIC_STRING + +class BERcodec_VIDEOTEX_STRING(BERcodec_STRING): + tag = ASN1_Class_UNIVERSAL.VIDEOTEX_STRING + +class BERcodec_IPADDRESS(BERcodec_STRING): + tag = ASN1_Class_UNIVERSAL.IPADDRESS + + @classmethod + def enc(cls, ipaddr_ascii): + try: + s = inet_aton(ipaddr_ascii) + except Exception: + raise BER_Encoding_Error("IPv4 address could not be encoded") + return chr(cls.tag)+BER_len_enc(len(s))+s + + @classmethod + def do_dec(cls, s, context=None, safe=False): + l,s,t = cls.check_type_check_len(s) + try: + ipaddr_ascii = inet_ntoa(s) + except Exception: + raise BER_Decoding_Error("IP address could not be decoded", decoded=obj) + return cls.asn1_object(ipaddr_ascii), t + +class BERcodec_UTC_TIME(BERcodec_STRING): + tag = ASN1_Class_UNIVERSAL.UTC_TIME + +class BERcodec_GENERALIZED_TIME(BERcodec_STRING): + tag = ASN1_Class_UNIVERSAL.GENERALIZED_TIME + +class BERcodec_TIME_TICKS(BERcodec_INTEGER): + tag = ASN1_Class_UNIVERSAL.TIME_TICKS + +class BERcodec_GAUGE32(BERcodec_INTEGER): + tag = ASN1_Class_UNIVERSAL.GAUGE32 + +class BERcodec_COUNTER32(BERcodec_INTEGER): + tag = ASN1_Class_UNIVERSAL.COUNTER32 + +class BERcodec_SEQUENCE(BERcodec_Object): + tag = ASN1_Class_UNIVERSAL.SEQUENCE + @classmethod + def enc(cls, l): + if type(l) is not str: + l = "".join(map(lambda x: x.enc(cls.codec), l)) + return chr(cls.tag)+BER_len_enc(len(l))+l + @classmethod + def do_dec(cls, s, context=None, safe=False): + if context is None: + context = cls.tag.context + l,st = cls.check_type_get_len(s) # we may have len(s) < l + s,t = st[:l],st[l:] + obj = [] + while s: + try: + o,s = BERcodec_Object.dec(s, context, safe) + except BER_Decoding_Error, err: + err.remaining += t + if err.decoded is not None: + obj.append(err.decoded) + err.decoded = obj + raise + obj.append(o) + if len(st) < l: + raise BER_Decoding_Error("Not enough bytes to decode sequence", decoded=obj) + return cls.asn1_object(obj),t + +class BERcodec_SET(BERcodec_SEQUENCE): + tag = ASN1_Class_UNIVERSAL.SET + + +class BERcodec_OID(BERcodec_Object): + tag = ASN1_Class_UNIVERSAL.OID + + @classmethod + def enc(cls, oid): + lst = [int(x) for x in oid.strip(".").split(".")] + if len(lst) >= 2: + lst[1] += 40*lst[0] + del(lst[0]) + s = "".join([BER_num_enc(k) for k in lst]) + return chr(cls.tag)+BER_len_enc(len(s))+s + @classmethod + def do_dec(cls, s, context=None, safe=False): + l,s,t = cls.check_type_check_len(s) + lst = [] + while s: + l,s = BER_num_dec(s) + lst.append(l) + if (len(lst) > 0): + lst.insert(0,lst[0]/40) + lst[1] %= 40 + return cls.asn1_object(".".join([str(k) for k in lst])), t + + |