freeipa/ipalib/x509.py
Fraser Tweedale b0430b67dc Remove __main__ code from ipalib.x509 and ipalib.pkcs10
This code was presumably once used for testing, but has been
subsumed by the actual test suite.

Part of: https://fedorahosted.org/freeipa/ticket/6398

Reviewed-By: Jan Cholasta <jcholast@redhat.com>
Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>
2016-11-10 10:21:47 +01:00

488 lines
14 KiB
Python

# 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/>.
# Certificates should be stored internally DER-encoded. We can be passed
# a certificate several ways: read if from LDAP, read it from a 3rd party
# app (dogtag, candlepin, etc) or as user input. The normalize_certificate()
# function will convert an incoming certificate to DER-encoding.
# Conventions
#
# Where possible the following naming conventions are used:
#
# cert: the certificate is a PEM-encoded certificate
# dercert: the certificate is DER-encoded
# rawcert: the cert is in an unknown format
from __future__ import print_function
import binascii
import datetime
import ipaddress
import base64
import re
from cryptography.hazmat.backends import default_backend
import cryptography.x509
from pyasn1.type import univ, char, namedtype, tag
from pyasn1.codec.der import decoder, encoder
from pyasn1_modules import rfc2459
import six
from ipalib import api
from ipalib import util
from ipalib import errors
from ipapython.dn import DN
if six.PY3:
unicode = str
PEM = 0
DER = 1
PEM_REGEX = re.compile(r'(?<=-----BEGIN CERTIFICATE-----).*?(?=-----END CERTIFICATE-----)', re.DOTALL)
EKU_SERVER_AUTH = '1.3.6.1.5.5.7.3.1'
EKU_CLIENT_AUTH = '1.3.6.1.5.5.7.3.2'
EKU_CODE_SIGNING = '1.3.6.1.5.5.7.3.3'
EKU_EMAIL_PROTECTION = '1.3.6.1.5.5.7.3.4'
EKU_ANY = '2.5.29.37.0'
EKU_PLACEHOLDER = '1.3.6.1.4.1.3319.6.10.16'
SAN_UPN = '1.3.6.1.4.1.311.20.2.3'
SAN_KRB5PRINCIPALNAME = '1.3.6.1.5.2.2'
_subject_base = None
def subject_base():
global _subject_base
if _subject_base is None:
config = api.Command['config_show']()['result']
_subject_base = DN(config['ipacertificatesubjectbase'][0])
return _subject_base
def strip_header(pem):
"""
Remove the header and footer from a certificate.
"""
s = pem.find("-----BEGIN CERTIFICATE-----")
if s >= 0:
e = pem.find("-----END CERTIFICATE-----")
pem = pem[s+27:e]
return pem
def load_certificate(data, datatype=PEM):
"""
Load an X.509 certificate.
:param datatype: PEM for base64-encoded data (with or without header),
or DER
:return: a python-cryptography ``CertificateSigningRequest`` object.
:raises: ``ValueError`` if unable to load the certificate.
"""
if type(data) in (tuple, list):
data = data[0]
if (datatype == PEM):
data = strip_header(data)
data = base64.b64decode(data)
return cryptography.x509.load_der_x509_certificate(data, default_backend())
def load_certificate_from_file(filename, dbdir=None):
"""
Load a certificate from a PEM file.
Returns a python-cryptography ``Certificate`` object.
"""
with open(filename, mode='rb') as f:
return load_certificate(f.read(), PEM)
def load_certificate_list(data):
"""
Load a certificate list from a sequence of concatenated PEMs.
Return a list of python-cryptography ``Certificate`` objects.
"""
certs = PEM_REGEX.findall(data)
certs = [load_certificate(cert, PEM) for cert in certs]
return certs
def load_certificate_list_from_file(filename):
"""
Load a certificate list from a PEM file.
Return a list of python-cryptography ``Certificate`` objects.
"""
with open(filename) as f:
return load_certificate_list(f.read())
def is_self_signed(certificate, datatype=PEM):
cert = load_certificate(certificate, datatype)
return cert.issuer == cert.subject
def _get_der_field(cert, datatype, dbdir, field):
cert = normalize_certificate(cert)
cert = decoder.decode(cert, rfc2459.Certificate())[0]
field = cert['tbsCertificate'][field]
field = encoder.encode(field)
return field
def get_der_subject(cert, datatype=PEM, dbdir=None):
return _get_der_field(cert, datatype, dbdir, 'subject')
def get_der_issuer(cert, datatype=PEM, dbdir=None):
return _get_der_field(cert, datatype, dbdir, 'issuer')
def get_der_serial_number(cert, datatype=PEM, dbdir=None):
return _get_der_field(cert, datatype, dbdir, 'serialNumber')
def get_der_public_key_info(cert, datatype=PEM, dbdir=None):
return _get_der_field(cert, datatype, dbdir, 'subjectPublicKeyInfo')
def get_ext_key_usage(certificate, datatype=PEM):
cert = load_certificate(certificate, datatype)
try:
eku = cert.extensions.get_extension_for_oid(
cryptography.x509.oid.ExtensionOID.EXTENDED_KEY_USAGE).value
except cryptography.x509.ExtensionNotFound:
return None
return set(oid.dotted_string for oid in eku)
def make_pem(data):
"""
Convert a raw base64-encoded blob into something that looks like a PE
file with lines split to 64 characters and proper headers.
"""
if isinstance(data, bytes):
data = data.decode('ascii')
pemcert = '\r\n'.join([data[x:x+64] for x in range(0, len(data), 64)])
return '-----BEGIN CERTIFICATE-----\n' + \
pemcert + \
'\n-----END CERTIFICATE-----'
def normalize_certificate(rawcert):
"""
Incoming certificates should be DER-encoded. If not it is converted to
DER-format.
Note that this can't be a normalizer on a Param because only unicode
variables are normalized.
"""
if not rawcert:
return None
rawcert = strip_header(rawcert)
if util.isvalid_base64(rawcert):
try:
dercert = base64.b64decode(rawcert)
except Exception as e:
raise errors.Base64DecodeError(reason=str(e))
else:
dercert = rawcert
# At this point we should have a DER certificate.
# Attempt to decode it.
validate_certificate(dercert, datatype=DER)
return dercert
def validate_certificate(cert, datatype=PEM):
"""
Perform cert validation by trying to load it via python-cryptography.
"""
try:
load_certificate(cert, datatype=datatype)
except ValueError as e:
raise errors.CertificateFormatError(error=str(e))
def write_certificate(rawcert, filename):
"""
Write the certificate to a file in PEM format.
The cert value can be either DER or PEM-encoded, it will be normalized
to DER regardless, then back out to PEM.
"""
dercert = normalize_certificate(rawcert)
try:
fp = open(filename, 'w')
fp.write(make_pem(base64.b64encode(dercert)))
fp.close()
except (IOError, OSError) as e:
raise errors.FileError(reason=str(e))
def write_certificate_list(rawcerts, filename):
"""
Write a list of certificates to a file in PEM format.
The cert values can be either DER or PEM-encoded, they will be normalized
to DER regardless, then back out to PEM.
"""
dercerts = [normalize_certificate(rawcert) for rawcert in rawcerts]
try:
with open(filename, 'w') as f:
for cert in dercerts:
cert = base64.b64encode(cert)
cert = make_pem(cert)
f.write(cert + '\n')
except (IOError, OSError) as e:
raise errors.FileError(reason=str(e))
def _encode_extension(oid, critical, value):
ext = rfc2459.Extension()
ext['extnID'] = univ.ObjectIdentifier(oid)
ext['critical'] = univ.Boolean(critical)
ext['extnValue'] = univ.Any(encoder.encode(univ.OctetString(value)))
ext = encoder.encode(ext)
return ext
def encode_ext_key_usage(ext_key_usage):
eku = rfc2459.ExtKeyUsageSyntax()
for i, oid in enumerate(ext_key_usage):
eku[i] = univ.ObjectIdentifier(oid)
eku = encoder.encode(eku)
return _encode_extension('2.5.29.37', EKU_ANY not in ext_key_usage, eku)
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 KRB5PrincipalName(cryptography.x509.general_name.OtherName):
def __init__(self, type_id, value):
super(KRB5PrincipalName, self).__init__(type_id, value)
self.name = _decode_krb5principalname(value)
class UPN(cryptography.x509.general_name.OtherName):
def __init__(self, type_id, value):
super(UPN, self).__init__(type_id, value)
self.name = unicode(
decoder.decode(value, asn1Spec=char.UTF8String())[0])
OTHERNAME_CLASS_MAP = {
SAN_KRB5PRINCIPALNAME: KRB5PrincipalName,
SAN_UPN: UPN,
}
def process_othernames(gns):
"""
Process python-cryptography GeneralName values, yielding
OtherName values of more specific type if type is known.
"""
for gn in gns:
if isinstance(gn, cryptography.x509.general_name.OtherName):
cls = OTHERNAME_CLASS_MAP.get(
gn.type_id.dotted_string,
cryptography.x509.general_name.OtherName)
yield cls(gn.type_id, gn.value)
else:
yield gn
def get_san_general_names(cert):
"""
Return SAN general names from a python-cryptography
certificate object. If the SAN extension is not present,
return an empty sequence.
Because python-cryptography does not yet provide a way to
handle unrecognised critical extensions (which may occur),
we must parse the certificate and extract the General Names.
For uniformity with other code, we manually construct values
of python-crytography GeneralName subtypes.
python-cryptography does not yet provide types for
ediPartyName or x400Address, so we drop these name types.
otherNames are NOT instantiated to more specific types where
the type is known. Use ``process_othernames`` to do that.
When python-cryptography can handle certs with unrecognised
critical extensions and implements ediPartyName and
x400Address, this function (and helpers) will be redundant
and should go away.
"""
tbs = decoder.decode(
cert.tbs_certificate_bytes,
asn1Spec=rfc2459.TBSCertificate()
)[0]
OID_SAN = univ.ObjectIdentifier('2.5.29.17')
gns = []
for ext in tbs['extensions']:
if ext['extnID'] == OID_SAN:
der = decoder.decode(
ext['extnValue'], asn1Spec=univ.OctetString())[0]
gns = decoder.decode(der, asn1Spec=rfc2459.SubjectAltName())[0]
break
GENERAL_NAME_CONSTRUCTORS = {
'rfc822Name': lambda x: cryptography.x509.RFC822Name(unicode(x)),
'dNSName': lambda x: cryptography.x509.DNSName(unicode(x)),
'directoryName': _pyasn1_to_cryptography_directoryname,
'registeredID': _pyasn1_to_cryptography_registeredid,
'iPAddress': _pyasn1_to_cryptography_ipaddress,
'uniformResourceIdentifier':
lambda x: cryptography.x509.UniformResourceIdentifier(unicode(x)),
'otherName': _pyasn1_to_cryptography_othername,
}
result = []
for gn in gns:
gn_type = gn.getName()
if gn_type in GENERAL_NAME_CONSTRUCTORS:
result.append(
GENERAL_NAME_CONSTRUCTORS[gn_type](gn.getComponent()))
return result
def _pyasn1_to_cryptography_directoryname(dn):
attrs = []
# Name is CHOICE { RDNSequence } (only one possibility)
for rdn in dn.getComponent():
for ava in rdn:
attr = cryptography.x509.NameAttribute(
_pyasn1_to_cryptography_oid(ava['type']),
unicode(decoder.decode(ava['value'])[0])
)
attrs.append(attr)
return cryptography.x509.DirectoryName(cryptography.x509.Name(attrs))
def _pyasn1_to_cryptography_registeredid(oid):
return cryptography.x509.RegisteredID(_pyasn1_to_cryptography_oid(oid))
def _pyasn1_to_cryptography_ipaddress(octet_string):
return cryptography.x509.IPAddress(
ipaddress.ip_address(bytes(octet_string)))
def _pyasn1_to_cryptography_othername(on):
return cryptography.x509.OtherName(
_pyasn1_to_cryptography_oid(on['type-id']),
bytes(on['value'])
)
def _pyasn1_to_cryptography_oid(oid):
return cryptography.x509.ObjectIdentifier(str(oid))
def chunk(size, s):
"""Yield chunks of the specified size from the given string.
The input must be a multiple of the chunk size (otherwise
trailing characters are dropped).
Works on character strings only.
"""
return (u''.join(span) for span in six.moves.zip(*[iter(s)] * size))
def add_colons(s):
"""Add colons between each nibble pair in a hex string."""
return u':'.join(chunk(2, s))
def to_hex_with_colons(bs):
"""Convert bytes to a hex string with colons."""
return add_colons(binascii.hexlify(bs).decode('utf-8'))
class UTC(datetime.tzinfo):
ZERO = datetime.timedelta(0)
def tzname(self, dt):
return "UTC"
def utcoffset(self, dt):
return self.ZERO
def dst(self, dt):
return self.ZERO
def format_datetime(t):
if t.tzinfo is None:
t = t.replace(tzinfo=UTC())
return unicode(t.strftime("%a %b %d %H:%M:%S %Y %Z"))