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dae82b25bd
The subjectAltName extension parsing code in ipalib.x509 fails on directoryName values because the Choice structure is not endowed with an inner type. Implement the Name structure, whose inner type is a CHOICE { SEQUENCE OF RelativeDistinguishedName }, to resolve. Note that the structure still does not get fully parsed; only enough to recognise the SequenceOf tag and not fail. Part of: https://fedorahosted.org/freeipa/ticket/6022 Reviewed-By: Jan Cholasta <jcholast@redhat.com>
512 lines
16 KiB
Python
512 lines
16 KiB
Python
# Authors:
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# Rob Crittenden <rcritten@redhat.com>
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#
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# Copyright (C) 2010 Red Hat
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# see file 'COPYING' for use and warranty information
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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# Certificates should be stored internally DER-encoded. We can be passed
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# a certificate several ways: read if from LDAP, read it from a 3rd party
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# app (dogtag, candlepin, etc) or as user input. The normalize_certificate()
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# function will convert an incoming certificate to DER-encoding.
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# Conventions
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#
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# Where possible the following naming conventions are used:
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#
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# cert: the certificate is a PEM-encoded certificate
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# dercert: the certificate is DER-encoded
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# nsscert: the certificate is an NSS Certificate object
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# rawcert: the cert is in an unknown format
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from __future__ import print_function
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import os
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import sys
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import base64
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import re
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import nss.nss as nss
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from nss.error import NSPRError
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from pyasn1.type import univ, char, namedtype, tag
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from pyasn1.codec.der import decoder, encoder
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import six
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from ipalib import api
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from ipalib import _
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from ipalib import util
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from ipalib import errors
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from ipaplatform.paths import paths
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from ipapython.dn import DN
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PEM = 0
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DER = 1
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PEM_REGEX = re.compile(r'(?<=-----BEGIN CERTIFICATE-----).*?(?=-----END CERTIFICATE-----)', re.DOTALL)
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EKU_SERVER_AUTH = '1.3.6.1.5.5.7.3.1'
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EKU_CLIENT_AUTH = '1.3.6.1.5.5.7.3.2'
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EKU_CODE_SIGNING = '1.3.6.1.5.5.7.3.3'
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EKU_EMAIL_PROTECTION = '1.3.6.1.5.5.7.3.4'
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EKU_ANY = '2.5.29.37.0'
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EKU_PLACEHOLDER = '1.3.6.1.4.1.3319.6.10.16'
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SAN_DNSNAME = 'DNS name'
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SAN_RFC822NAME = 'RFC822 Name'
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SAN_OTHERNAME_UPN = 'Other Name (OID.1.3.6.1.4.1.311.20.2.3)'
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SAN_OTHERNAME_KRB5PRINCIPALNAME = 'Other Name (OID.1.3.6.1.5.2.2)'
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_subject_base = None
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def subject_base():
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global _subject_base
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if _subject_base is None:
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config = api.Command['config_show']()['result']
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_subject_base = DN(config['ipacertificatesubjectbase'][0])
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return _subject_base
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def strip_header(pem):
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"""
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Remove the header and footer from a certificate.
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"""
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s = pem.find("-----BEGIN CERTIFICATE-----")
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if s >= 0:
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e = pem.find("-----END CERTIFICATE-----")
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pem = pem[s+27:e]
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return pem
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def initialize_nss_database(dbdir=None):
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"""
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Initializes NSS database, if not initialized yet. Uses a proper database
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directory (.ipa/alias or HTTPD_ALIAS_DIR), depending on the value of
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api.env.in_tree.
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"""
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if not nss.nss_is_initialized():
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if dbdir is None:
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if 'in_tree' in api.env:
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if api.env.in_tree:
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dbdir = api.env.dot_ipa + os.sep + 'alias'
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else:
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dbdir = paths.HTTPD_ALIAS_DIR
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nss.nss_init(dbdir)
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else:
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nss.nss_init_nodb()
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else:
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nss.nss_init(dbdir)
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def load_certificate(data, datatype=PEM, dbdir=None):
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"""
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Given a base64-encoded certificate, with or without the
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header/footer, return a request object.
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Returns a nss.Certificate type
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"""
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if type(data) in (tuple, list):
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data = data[0]
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if (datatype == PEM):
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data = strip_header(data)
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data = base64.b64decode(data)
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initialize_nss_database(dbdir=dbdir)
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if six.PY2:
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return nss.Certificate(buffer(data)) # pylint: disable=buffer-builtin
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else:
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# In python 3 , `bytes` has the buffer interface
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return nss.Certificate(data)
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def load_certificate_from_file(filename, dbdir=None):
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"""
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Load a certificate from a PEM file.
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Returns a nss.Certificate type
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"""
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fd = open(filename, 'r')
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data = fd.read()
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fd.close()
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return load_certificate(data, PEM, dbdir)
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def load_certificate_list(data, dbdir=None):
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certs = PEM_REGEX.findall(data)
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certs = [load_certificate(cert, PEM, dbdir) for cert in certs]
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return certs
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def load_certificate_list_from_file(filename, dbdir=None):
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"""
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Load a certificate list from a PEM file.
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Returns a list of nss.Certificate objects.
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"""
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fd = open(filename, 'r')
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data = fd.read()
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fd.close()
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return load_certificate_list(data, dbdir)
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def get_subject(certificate, datatype=PEM, dbdir=None):
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"""
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Load an X509.3 certificate and get the subject.
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"""
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nsscert = load_certificate(certificate, datatype, dbdir)
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subject = nsscert.subject
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del(nsscert)
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return subject
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def get_issuer(certificate, datatype=PEM, dbdir=None):
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"""
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Load an X509.3 certificate and get the issuer.
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"""
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nsscert = load_certificate(certificate, datatype, dbdir)
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issuer = nsscert.issuer
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del(nsscert)
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return issuer
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def get_serial_number(certificate, datatype=PEM, dbdir=None):
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"""
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Return the decimal value of the serial number.
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"""
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nsscert = load_certificate(certificate, datatype, dbdir)
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serial_number = nsscert.serial_number
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del(nsscert)
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return serial_number
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def is_self_signed(certificate, datatype=PEM, dbdir=None):
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nsscert = load_certificate(certificate, datatype, dbdir)
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self_signed = (nsscert.issuer == nsscert.subject)
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del nsscert
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return self_signed
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class _Name(univ.Choice):
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componentType = namedtype.NamedTypes(
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namedtype.NamedType('rdnSequence',
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univ.SequenceOf()),
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)
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class _TBSCertificate(univ.Sequence):
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componentType = namedtype.NamedTypes(
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namedtype.NamedType(
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'version',
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univ.Integer().subtype(explicitTag=tag.Tag(
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tag.tagClassContext, tag.tagFormatSimple, 0))),
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namedtype.NamedType('serialNumber', univ.Integer()),
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namedtype.NamedType('signature', univ.Sequence()),
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namedtype.NamedType('issuer', _Name()),
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namedtype.NamedType('validity', univ.Sequence()),
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namedtype.NamedType('subject', _Name()),
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namedtype.NamedType('subjectPublicKeyInfo', univ.Sequence()),
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namedtype.OptionalNamedType(
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'issuerUniquedID',
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univ.BitString().subtype(implicitTag=tag.Tag(
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tag.tagClassContext, tag.tagFormatSimple, 1))),
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namedtype.OptionalNamedType(
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'subjectUniquedID',
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univ.BitString().subtype(implicitTag=tag.Tag(
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tag.tagClassContext, tag.tagFormatSimple, 2))),
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namedtype.OptionalNamedType(
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'extensions',
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univ.Sequence().subtype(explicitTag=tag.Tag(
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tag.tagClassContext, tag.tagFormatSimple, 3))),
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)
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class _Certificate(univ.Sequence):
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componentType = namedtype.NamedTypes(
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namedtype.NamedType('tbsCertificate', _TBSCertificate()),
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namedtype.NamedType('signatureAlgorithm', univ.Sequence()),
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namedtype.NamedType('signature', univ.BitString()),
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)
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def _get_der_field(cert, datatype, dbdir, field):
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cert = load_certificate(cert, datatype, dbdir)
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cert = cert.der_data
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cert = decoder.decode(cert, _Certificate())[0]
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field = cert['tbsCertificate'][field]
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field = encoder.encode(field)
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return field
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def get_der_subject(cert, datatype=PEM, dbdir=None):
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return _get_der_field(cert, datatype, dbdir, 'subject')
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def get_der_issuer(cert, datatype=PEM, dbdir=None):
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return _get_der_field(cert, datatype, dbdir, 'issuer')
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def get_der_serial_number(cert, datatype=PEM, dbdir=None):
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return _get_der_field(cert, datatype, dbdir, 'serialNumber')
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def get_der_public_key_info(cert, datatype=PEM, dbdir=None):
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return _get_der_field(cert, datatype, dbdir, 'subjectPublicKeyInfo')
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def get_ext_key_usage(certificate, datatype=PEM, dbdir=None):
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nsscert = load_certificate(certificate, datatype, dbdir)
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if not nsscert.extensions:
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return None
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for ext in nsscert.extensions:
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if ext.oid_tag == nss.SEC_OID_X509_EXT_KEY_USAGE:
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break
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else:
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return None
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eku = nss.x509_ext_key_usage(ext.value, nss.AsDottedDecimal)
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eku = set(o[4:] for o in eku)
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return eku
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def make_pem(data):
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"""
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Convert a raw base64-encoded blob into something that looks like a PE
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file with lines split to 64 characters and proper headers.
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"""
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if isinstance(data, bytes):
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data = data.decode('ascii')
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pemcert = '\r\n'.join([data[x:x+64] for x in range(0, len(data), 64)])
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return '-----BEGIN CERTIFICATE-----\n' + \
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pemcert + \
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'\n-----END CERTIFICATE-----'
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def normalize_certificate(rawcert):
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"""
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Incoming certificates should be DER-encoded. If not it is converted to
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DER-format.
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Note that this can't be a normalizer on a Param because only unicode
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variables are normalized.
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"""
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if not rawcert:
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return None
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rawcert = strip_header(rawcert)
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if util.isvalid_base64(rawcert):
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try:
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dercert = base64.b64decode(rawcert)
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except Exception as e:
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raise errors.Base64DecodeError(reason=str(e))
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else:
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dercert = rawcert
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# At this point we should have a certificate, either because the data
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# was base64-encoded and now its not or it came in as DER format.
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# Let's decode it and see. Fetching the serial number will pass the
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# certificate through the NSS DER parser.
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validate_certificate(dercert, datatype=DER)
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return dercert
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def validate_certificate(cert, datatype=PEM, dbdir=None):
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"""
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Perform certificate validation by trying to load it into NSS database
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"""
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try:
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load_certificate(cert, datatype=datatype, dbdir=dbdir)
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except NSPRError as nsprerr:
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if nsprerr.errno == -8183: # SEC_ERROR_BAD_DER
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raise errors.CertificateFormatError(
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error=_('improperly formatted DER-encoded certificate'))
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else:
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raise errors.CertificateFormatError(error=str(nsprerr))
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def write_certificate(rawcert, filename):
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"""
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Write the certificate to a file in PEM format.
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The cert value can be either DER or PEM-encoded, it will be normalized
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to DER regardless, then back out to PEM.
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"""
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dercert = normalize_certificate(rawcert)
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try:
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fp = open(filename, 'w')
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fp.write(make_pem(base64.b64encode(dercert)))
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fp.close()
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except (IOError, OSError) as e:
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raise errors.FileError(reason=str(e))
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def write_certificate_list(rawcerts, filename):
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"""
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Write a list of certificates to a file in PEM format.
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The cert values can be either DER or PEM-encoded, they will be normalized
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to DER regardless, then back out to PEM.
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"""
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dercerts = [normalize_certificate(rawcert) for rawcert in rawcerts]
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try:
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with open(filename, 'w') as f:
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for cert in dercerts:
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cert = base64.b64encode(cert)
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cert = make_pem(cert)
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f.write(cert + '\n')
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except (IOError, OSError) as e:
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raise errors.FileError(reason=str(e))
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class _Extension(univ.Sequence):
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componentType = namedtype.NamedTypes(
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namedtype.NamedType('extnID', univ.ObjectIdentifier()),
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namedtype.NamedType('critical', univ.Boolean()),
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namedtype.NamedType('extnValue', univ.OctetString()),
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)
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def _encode_extension(oid, critical, value):
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ext = _Extension()
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ext['extnID'] = univ.ObjectIdentifier(oid)
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ext['critical'] = univ.Boolean(critical)
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ext['extnValue'] = univ.OctetString(value)
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ext = encoder.encode(ext)
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return ext
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class _ExtKeyUsageSyntax(univ.SequenceOf):
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componentType = univ.ObjectIdentifier()
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def encode_ext_key_usage(ext_key_usage):
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eku = _ExtKeyUsageSyntax()
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for i, oid in enumerate(ext_key_usage):
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eku[i] = univ.ObjectIdentifier(oid)
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eku = encoder.encode(eku)
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return _encode_extension('2.5.29.37', EKU_ANY not in ext_key_usage, eku)
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class _AnotherName(univ.Sequence):
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componentType = namedtype.NamedTypes(
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namedtype.NamedType('type-id', univ.ObjectIdentifier()),
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namedtype.NamedType('value', univ.Any().subtype(
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explicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 0))
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),
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)
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class _GeneralName(univ.Choice):
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componentType = namedtype.NamedTypes(
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namedtype.NamedType('otherName', _AnotherName().subtype(
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implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 0))
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),
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namedtype.NamedType('rfc822Name', char.IA5String().subtype(
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implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 1))
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),
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namedtype.NamedType('dNSName', char.IA5String().subtype(
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implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 2))
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),
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namedtype.NamedType('x400Address', univ.Sequence().subtype(
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implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 3))
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),
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namedtype.NamedType('directoryName', _Name().subtype(
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implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 4))
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),
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namedtype.NamedType('ediPartyName', univ.Sequence().subtype(
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implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 5))
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),
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namedtype.NamedType('uniformResourceIdentifier', char.IA5String().subtype(
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implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 6))
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),
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namedtype.NamedType('iPAddress', univ.OctetString().subtype(
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implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 7))
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),
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namedtype.NamedType('registeredID', univ.ObjectIdentifier().subtype(
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implicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 8))
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),
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)
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class _SubjectAltName(univ.SequenceOf):
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componentType = _GeneralName()
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class _PrincipalName(univ.Sequence):
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componentType = namedtype.NamedTypes(
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namedtype.NamedType('name-type', univ.Integer().subtype(
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explicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 0))
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),
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namedtype.NamedType('name-string', univ.SequenceOf(char.GeneralString()).subtype(
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explicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 1))
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),
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)
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class _KRB5PrincipalName(univ.Sequence):
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componentType = namedtype.NamedTypes(
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namedtype.NamedType('realm', char.GeneralString().subtype(
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explicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 0))
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),
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namedtype.NamedType('principalName', _PrincipalName().subtype(
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explicitTag=tag.Tag(tag.tagClassContext, tag.tagFormatSimple, 1))
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),
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)
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def _decode_krb5principalname(data):
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principal = decoder.decode(data, asn1Spec=_KRB5PrincipalName())[0]
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realm = (str(principal['realm']).replace('\\', '\\\\')
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.replace('@', '\\@'))
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name = principal['principalName']['name-string']
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name = '/'.join(str(n).replace('\\', '\\\\')
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.replace('/', '\\/')
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.replace('@', '\\@') for n in name)
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name = '%s@%s' % (name, realm)
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return name
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def decode_generalnames(secitem):
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"""
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Decode a GeneralNames object (this the data for the Subject
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Alt Name and Issuer Alt Name extensions, among others).
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``secitem``
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The input is the DER-encoded extension data, without the
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OCTET STRING header, as an nss SecItem object.
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Return a list of tuples of name types (as string, suitable for
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presentation) and names (as string, suitable for presentation).
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"""
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nss_names = nss.x509_alt_name(secitem, repr_kind=nss.AsObject)
|
|
asn1_names = decoder.decode(secitem.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 names
|
|
|
|
|
|
if __name__ == '__main__':
|
|
# this can be run with:
|
|
# python ipalib/x509.py < /etc/ipa/ca.crt
|
|
|
|
api.bootstrap()
|
|
api.finalize()
|
|
|
|
nss.nss_init_nodb()
|
|
|
|
# Read PEM certs from stdin and print out its components
|
|
|
|
certlines = sys.stdin.readlines()
|
|
cert = ''.join(certlines)
|
|
|
|
nsscert = load_certificate(cert)
|
|
|
|
print(nsscert)
|