You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
115 lines
3.7 KiB
115 lines
3.7 KiB
#
|
|
# This file is part of pyasn1 software.
|
|
#
|
|
# Copyright (c) 2005-2019, Ilya Etingof <etingof@gmail.com>
|
|
# License: http://snmplabs.com/pyasn1/license.html
|
|
#
|
|
from pyasn1 import error
|
|
from pyasn1.codec.ber import decoder
|
|
from pyasn1.compat.octets import oct2int
|
|
from pyasn1.type import univ
|
|
|
|
__all__ = ['decode']
|
|
|
|
|
|
class BooleanDecoder(decoder.AbstractSimpleDecoder):
|
|
protoComponent = univ.Boolean(0)
|
|
|
|
def valueDecoder(self, substrate, asn1Spec,
|
|
tagSet=None, length=None, state=None,
|
|
decodeFun=None, substrateFun=None,
|
|
**options):
|
|
head, tail = substrate[:length], substrate[length:]
|
|
if not head or length != 1:
|
|
raise error.PyAsn1Error('Not single-octet Boolean payload')
|
|
byte = oct2int(head[0])
|
|
# CER/DER specifies encoding of TRUE as 0xFF and FALSE as 0x0, while
|
|
# BER allows any non-zero value as TRUE; cf. sections 8.2.2. and 11.1
|
|
# in https://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
|
|
if byte == 0xff:
|
|
value = 1
|
|
elif byte == 0x00:
|
|
value = 0
|
|
else:
|
|
raise error.PyAsn1Error('Unexpected Boolean payload: %s' % byte)
|
|
return self._createComponent(asn1Spec, tagSet, value, **options), tail
|
|
|
|
# TODO: prohibit non-canonical encoding
|
|
BitStringDecoder = decoder.BitStringDecoder
|
|
OctetStringDecoder = decoder.OctetStringDecoder
|
|
RealDecoder = decoder.RealDecoder
|
|
|
|
tagMap = decoder.tagMap.copy()
|
|
tagMap.update(
|
|
{univ.Boolean.tagSet: BooleanDecoder(),
|
|
univ.BitString.tagSet: BitStringDecoder(),
|
|
univ.OctetString.tagSet: OctetStringDecoder(),
|
|
univ.Real.tagSet: RealDecoder()}
|
|
)
|
|
|
|
typeMap = decoder.typeMap.copy()
|
|
|
|
# Put in non-ambiguous types for faster codec lookup
|
|
for typeDecoder in tagMap.values():
|
|
if typeDecoder.protoComponent is not None:
|
|
typeId = typeDecoder.protoComponent.__class__.typeId
|
|
if typeId is not None and typeId not in typeMap:
|
|
typeMap[typeId] = typeDecoder
|
|
|
|
|
|
class Decoder(decoder.Decoder):
|
|
pass
|
|
|
|
|
|
#: Turns CER octet stream into an ASN.1 object.
|
|
#:
|
|
#: Takes CER octet-stream and decode it into an ASN.1 object
|
|
#: (e.g. :py:class:`~pyasn1.type.base.PyAsn1Item` derivative) which
|
|
#: may be a scalar or an arbitrary nested structure.
|
|
#:
|
|
#: Parameters
|
|
#: ----------
|
|
#: substrate: :py:class:`bytes` (Python 3) or :py:class:`str` (Python 2)
|
|
#: CER octet-stream
|
|
#:
|
|
#: Keyword Args
|
|
#: ------------
|
|
#: asn1Spec: any pyasn1 type object e.g. :py:class:`~pyasn1.type.base.PyAsn1Item` derivative
|
|
#: A pyasn1 type object to act as a template guiding the decoder. Depending on the ASN.1 structure
|
|
#: being decoded, *asn1Spec* may or may not be required. Most common reason for
|
|
#: it to require is that ASN.1 structure is encoded in *IMPLICIT* tagging mode.
|
|
#:
|
|
#: Returns
|
|
#: -------
|
|
#: : :py:class:`tuple`
|
|
#: A tuple of pyasn1 object recovered from CER substrate (:py:class:`~pyasn1.type.base.PyAsn1Item` derivative)
|
|
#: and the unprocessed trailing portion of the *substrate* (may be empty)
|
|
#:
|
|
#: Raises
|
|
#: ------
|
|
#: ~pyasn1.error.PyAsn1Error, ~pyasn1.error.SubstrateUnderrunError
|
|
#: On decoding errors
|
|
#:
|
|
#: Examples
|
|
#: --------
|
|
#: Decode CER serialisation without ASN.1 schema
|
|
#:
|
|
#: .. code-block:: pycon
|
|
#:
|
|
#: >>> s, _ = decode(b'0\x80\x02\x01\x01\x02\x01\x02\x02\x01\x03\x00\x00')
|
|
#: >>> str(s)
|
|
#: SequenceOf:
|
|
#: 1 2 3
|
|
#:
|
|
#: Decode CER serialisation with ASN.1 schema
|
|
#:
|
|
#: .. code-block:: pycon
|
|
#:
|
|
#: >>> seq = SequenceOf(componentType=Integer())
|
|
#: >>> s, _ = decode(b'0\x80\x02\x01\x01\x02\x01\x02\x02\x01\x03\x00\x00', asn1Spec=seq)
|
|
#: >>> str(s)
|
|
#: SequenceOf:
|
|
#: 1 2 3
|
|
#:
|
|
decode = Decoder(tagMap, decoder.typeMap)
|