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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, namedtype, tag
from pyasn1.codec.der import decoder
from ipapython import ipautil
from ipalib import api
PEM = 0
DER = 1
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_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)
try:
for extension in request.extensions:
if extension.oid_tag == nss.SEC_OID_X509_SUBJECT_ALT_NAME:
return nss.x509_alt_name(extension.value)
finally:
del request
return None
# 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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