我有一些数据是由pyOpenSSL提供的,'0\r\x82\x0bexample.com'
。这应该是 subjectAltName X509 扩展的值。我尝试使用pyasn1对该扩展的ASN1规范的必要部分进行编码(基于pyasn1的一个示例):
from pyasn1.type import univ, constraint, char, namedtype
from pyasn1.codec.der.decoder import decode
MAX = 64
class DirectoryString(univ.Choice):
componentType = namedtype.NamedTypes(
namedtype.NamedType(
'teletexString', char.TeletexString().subtype(
subtypeSpec=constraint.ValueSizeConstraint(1, MAX))),
namedtype.NamedType(
'printableString', char.PrintableString().subtype(
subtypeSpec=constraint.ValueSizeConstraint(1, MAX))),
namedtype.NamedType(
'universalString', char.UniversalString().subtype(
subtypeSpec=constraint.ValueSizeConstraint(1, MAX))),
namedtype.NamedType(
'utf8String', char.UTF8String().subtype(
subtypeSpec=constraint.ValueSizeConstraint(1, MAX))),
namedtype.NamedType(
'bmpString', char.BMPString().subtype(
subtypeSpec=constraint.ValueSizeConstraint(1, MAX))),
namedtype.NamedType(
'ia5String', char.IA5String().subtype(
subtypeSpec=constraint.ValueSizeConstraint(1, MAX))),
)
class AttributeValue(DirectoryString):
pass
class AttributeType(univ.ObjectIdentifier):
pass
class AttributeTypeAndValue(univ.Sequence):
componentType = namedtype.NamedTypes(
namedtype.NamedType('type', AttributeType()),
namedtype.NamedType('value', AttributeValue()),
)
class RelativeDistinguishedName(univ.SetOf):
componentType = AttributeTypeAndValue()
class RDNSequence(univ.SequenceOf):
componentType = RelativeDistinguishedName()
class Name(univ.Choice):
componentType = namedtype.NamedTypes(
namedtype.NamedType('', RDNSequence()),
)
class Extension(univ.Sequence):
componentType = namedtype.NamedTypes(
namedtype.NamedType('extnID', univ.ObjectIdentifier()),
namedtype.DefaultedNamedType('critical', univ.Boolean('False')),
namedtype.NamedType('extnValue', univ.OctetString()),
)
class Extensions(univ.SequenceOf):
componentType = Extension()
sizeSpec = univ.SequenceOf.sizeSpec + constraint.ValueSizeConstraint(1, MAX)
class GeneralName(univ.Choice):
componentType = namedtype.NamedTypes(
# namedtype.NamedType('otherName', AnotherName()),
namedtype.NamedType('rfc822Name', char.IA5String()),
namedtype.NamedType('dNSName', char.IA5String()),
# namedtype.NamedType('x400Address', ORAddress()),
namedtype.NamedType('directoryName', Name()),
# namedtype.NamedType('ediPartyName', EDIPartyName()),
namedtype.NamedType('uniformResourceIdentifier', char.IA5String()),
namedtype.NamedType('iPAddress', univ.OctetString()),
namedtype.NamedType('registeredID', univ.ObjectIdentifier()),
)
class GeneralNames(univ.SequenceOf):
componentType = GeneralName()
sizeSpec = univ.SequenceOf.sizeSpec + constraint.ValueSizeConstraint(1, MAX)
class SubjectAltName(GeneralNames):
pass
print decode('0\r\x82\x0bexample.com', asn1Spec=GeneralNames())
显然我在最后有点无聊了,没有完全指定GeneralName
类型。 然而,测试字符串应包含一个dNSName
,而不是跳过的值之一,因此我希望这并不重要。
运行程序时,它会失败并显示一个我无法解释的错误:
Traceback (most recent call last):
File "x509.py", line 94, in <module>
print decode('0\r\x82\x0bexample.com', asn1Spec=GeneralNames())
File "/usr/lib/pymodules/python2.6/pyasn1/v1/codec/ber/decoder.py", line 493, in __call__
length, stGetValueDecoder, decodeFun
File "/usr/lib/pymodules/python2.6/pyasn1/v1/codec/ber/decoder.py", line 202, in valueDecoder
substrate, asn1Spec
File "/usr/lib/pymodules/python2.6/pyasn1/v1/codec/ber/decoder.py", line 453, in __call__
__chosenSpec.getTypeMap().has_key(tagSet):
File "/usr/lib/pymodules/python2.6/pyasn1/v1/type/univ.py", line 608, in getTypeMap
return Set.getComponentTypeMap(self)
File "/usr/lib/pymodules/python2.6/pyasn1/v1/type/univ.py", line 535, in getComponentTypeMap
def getComponentTypeMap(self): return self._componentType.getTypeMap(1)
File "/usr/lib/pymodules/python2.6/pyasn1/v1/type/namedtype.py", line 126, in getTypeMap
'Duplicate type %s in map %s'%(k,self.__typeMap)
pyasn1.error.PyAsn1Error: Duplicate type TagSet(Tag(tagClass=0, tagFormat=0, tagId=22)) in map {TagSet(Tag(tagClass=0, tagFormat=0, tagId=22)): IA5String()}
任何有关如何成功使用 pyasn1 解析此扩展类型的提示将不胜感激。