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# Authors:
# Rob Crittenden <rcritten@redhat.com>
#
# Copyright (C) 2010 Red Hat
# see file 'COPYING' for use and warranty information
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import os
import sys
import base64
import nss.nss as nss
from pyasn1.type import univ, char, namedtype, tag
from pyasn1.codec.der import decoder
from ipapython import ipautil
from ipalib import api
PEM = 0
DER = 1
SAN_DNSNAME = 'DNS name'
SAN_RFC822NAME = 'RFC822 Name'
SAN_OTHERNAME_UPN = 'Other Name (OID.1.3.6.1.4.1.311.20.2.3)'
SAN_OTHERNAME_KRB5PRINCIPALNAME = 'Other Name (OID.1.3.6.1.5.2.2)'
def get_subject(csr, datatype=PEM):
"""
Given a CSR return the subject value.
This returns an nss.DN object.
"""
request = load_certificate_request(csr, datatype)
try:
return request.subject
finally:
del request
def get_extensions(csr, datatype=PEM):
"""
Given a CSR return OIDs of certificate extensions.
The return value is a tuple of strings
"""
request = load_certificate_request(csr, datatype)
return tuple(nss.oid_dotted_decimal(ext.oid_tag)[4:]
for ext in request.extensions)
class _PrincipalName(univ.Sequence):
componentType = namedtype.NamedTypes(
namedtype.NamedType('name-type', univ.Integer().subtype(
explicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 0))
),
namedtype.NamedType('name-string', univ.SequenceOf(char.GeneralString()).subtype(
explicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 1))
),
)
class _KRB5PrincipalName(univ.Sequence):
componentType = namedtype.NamedTypes(
namedtype.NamedType('realm', char.GeneralString().subtype(
explicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 0))
),
namedtype.NamedType('principalName', _PrincipalName().subtype(
explicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 1))
),
)
def _decode_krb5principalname(data):
principal = decoder.decode(data, asn1Spec=_KRB5PrincipalName())[0]
realm = (str(principal['realm']).replace('\\', '\\\\')
.replace('@', '\\@'))
name = principal['principalName']['name-string']
name = '/'.join(str(n).replace('\\', '\\\\')
.replace('/', '\\/')
.replace('@', '\\@') for n in name)
name = '%s@%s' % (name, realm)
return name
class _AnotherName(univ.Sequence):
componentType = namedtype.NamedTypes(
namedtype.NamedType('type-id', univ.ObjectIdentifier()),
namedtype.NamedType('value', univ.Any().subtype(
explicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 0))
),
)
class _GeneralName(univ.Choice):
componentType = namedtype.NamedTypes(
namedtype.NamedType('otherName', _AnotherName().subtype(
implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 0))
),
namedtype.NamedType('rfc822Name', char.IA5String().subtype(
implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 1))
),
namedtype.NamedType('dNSName', char.IA5String().subtype(
implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 2))
),
namedtype.NamedType('x400Address', univ.Sequence().subtype(
implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 3))
),
namedtype.NamedType('directoryName', univ.Choice().subtype(
implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 4))
),
namedtype.NamedType('ediPartyName', univ.Sequence().subtype(
implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 5))
),
namedtype.NamedType('uniformResourceIdentifier', char.IA5String().subtype(
implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 6))
),
namedtype.NamedType('iPAddress', univ.OctetString().subtype(
implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 7))
),
namedtype.NamedType('registeredID', univ.ObjectIdentifier().subtype(
implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 8))
),
)
class _SubjectAltName(univ.SequenceOf):
componentType = _GeneralName()
def get_subjectaltname(csr, datatype=PEM):
"""
Given a CSR return the subjectaltname value, if any.
The return value is a tuple of strings or None
"""
request = load_certificate_request(csr, datatype)
for extension in request.extensions:
if extension.oid_tag == nss.SEC_OID_X509_SUBJECT_ALT_NAME:
break
else:
return None
del request
nss_names = nss.x509_alt_name(extension.value, nss.AsObject)
asn1_names = decoder.decode(extension.value.data,
asn1Spec=_SubjectAltName())[0]
names = []
for nss_name, asn1_name in zip(nss_names, asn1_names):
name_type = nss_name.type_string
if name_type == SAN_OTHERNAME_KRB5PRINCIPALNAME:
name = _decode_krb5principalname(asn1_name['otherName']['value'])
else:
name = nss_name.name
names.append((name_type, name))
return tuple(names)
# Unfortunately, NSS can only parse the extension request attribute, so
# we have to parse friendly name ourselves (see RFC 2986)
class _Attribute(univ.Sequence):
componentType = namedtype.NamedTypes(
namedtype.NamedType('type', univ.ObjectIdentifier()),
namedtype.NamedType('values', univ.Set()),
)
class _Attributes(univ.SetOf):
componentType = _Attribute()
class _CertificationRequestInfo(univ.Sequence):
componentType = namedtype.NamedTypes(
namedtype.NamedType('version', univ.Integer()),
namedtype.NamedType('subject', univ.Sequence()),
namedtype.NamedType('subjectPublicKeyInfo', univ.Sequence()),
namedtype.OptionalNamedType('attributes', _Attributes().subtype(
implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 0)))
)
class _CertificationRequest(univ.Sequence):
componentType = namedtype.NamedTypes(
namedtype.NamedType('certificationRequestInfo',
_CertificationRequestInfo()),
namedtype.NamedType('signatureAlgorithm', univ.Sequence()),
namedtype.NamedType('signatureValue', univ.BitString()),
)
_FRIENDLYNAME = univ.ObjectIdentifier('1.2.840.113549.1.9.20')
def get_friendlyname(csr, datatype=PEM):
"""
Given a CSR return the value of the friendlyname attribute, if any.
The return value is a string.
"""
if datatype == PEM:
csr = strip_header(csr)
csr = base64.b64decode(csr)
csr = decoder.decode(csr, asn1Spec=_CertificationRequest())[0]
for attribute in csr['certificationRequestInfo']['attributes']:
if attribute['type'] == _FRIENDLYNAME:
return unicode(attribute['values'][0])
return None
def strip_header(csr):
"""
Remove the header and footer from a CSR.
"""
headerlen = 40
s = csr.find("-----BEGIN NEW CERTIFICATE REQUEST-----")
if s == -1:
headerlen = 36
s = csr.find("-----BEGIN CERTIFICATE REQUEST-----")
if s >= 0:
e = csr.find("-----END")
csr = csr[s+headerlen:e]
return csr
def load_certificate_request(csr, datatype=PEM):
"""
Given a base64-encoded certificate request, with or without the
header/footer, return a request object.
"""
if datatype == PEM:
csr = strip_header(csr)
csr = base64.b64decode(csr)
# A fail-safe so we can always read a CSR. python-nss/NSS will segfault
# otherwise
if not nss.nss_is_initialized():
nss.nss_init_nodb()
return nss.CertificateRequest(csr)
if __name__ == '__main__':
nss.nss_init_nodb()
# Read PEM request from stdin and print out its components
csrlines = sys.stdin.readlines()
csr = ''.join(csrlines)
print load_certificate_request(csr)
print get_subject(csr)
print get_subjectaltname(csr)
print get_friendlyname(csr)
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