1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
|
#
# 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 import streaming
from pyasn1.codec.ber import decoder
from pyasn1.compat.octets import oct2int
from pyasn1.type import univ
__all__ = ['decode', 'StreamingDecoder']
SubstrateUnderrunError = error.SubstrateUnderrunError
class BooleanPayloadDecoder(decoder.AbstractSimplePayloadDecoder):
protoComponent = univ.Boolean(0)
def valueDecoder(self, substrate, asn1Spec,
tagSet=None, length=None, state=None,
decodeFun=None, substrateFun=None,
**options):
if length != 1:
raise error.PyAsn1Error('Not single-octet Boolean payload')
for chunk in streaming.read(substrate, length, options):
if isinstance(chunk, SubstrateUnderrunError):
yield chunk
byte = oct2int(chunk[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)
yield self._createComponent(asn1Spec, tagSet, value, **options)
# TODO: prohibit non-canonical encoding
BitStringPayloadDecoder = decoder.BitStringPayloadDecoder
OctetStringPayloadDecoder = decoder.OctetStringPayloadDecoder
RealPayloadDecoder = decoder.RealPayloadDecoder
TAG_MAP = decoder.TAG_MAP.copy()
TAG_MAP.update(
{univ.Boolean.tagSet: BooleanPayloadDecoder(),
univ.BitString.tagSet: BitStringPayloadDecoder(),
univ.OctetString.tagSet: OctetStringPayloadDecoder(),
univ.Real.tagSet: RealPayloadDecoder()}
)
TYPE_MAP = decoder.TYPE_MAP.copy()
# Put in non-ambiguous types for faster codec lookup
for typeDecoder in TAG_MAP.values():
if typeDecoder.protoComponent is not None:
typeId = typeDecoder.protoComponent.__class__.typeId
if typeId is not None and typeId not in TYPE_MAP:
TYPE_MAP[typeId] = typeDecoder
class SingleItemDecoder(decoder.SingleItemDecoder):
__doc__ = decoder.SingleItemDecoder.__doc__
TAG_MAP = TAG_MAP
TYPE_MAP = TYPE_MAP
class StreamingDecoder(decoder.StreamingDecoder):
__doc__ = decoder.StreamingDecoder.__doc__
SINGLE_ITEM_DECODER = SingleItemDecoder
class Decoder(decoder.Decoder):
__doc__ = decoder.Decoder.__doc__
STREAMING_DECODER = StreamingDecoder
#: 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()
|
