1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
# Copyright (C) 2015 IPA Project Contributors, see COPYING for license
from __future__ import print_function
import os
# pylint: disable=import-error
from six.moves.configparser import ConfigParser
# pylint: enable=import-error
from ipaplatform.paths import paths
from ipapython.dn import DN
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import rsa, ec
from custodia.message.kem import KEMKeysStore
from custodia.message.kem import KEY_USAGE_SIG, KEY_USAGE_ENC, KEY_USAGE_MAP
from jwcrypto.common import json_decode, json_encode
from jwcrypto.common import base64url_encode
from jwcrypto.jwk import JWK
from ipaserver.secrets.common import iSecLdap
from binascii import unhexlify
import ldap
IPA_REL_BASE_DN = 'cn=custodia,cn=ipa,cn=etc'
IPA_KEYS_QUERY = '(&(ipaKeyUsage={usage:s})(memberPrincipal={princ:s}))'
IPA_CHECK_QUERY = '(cn=enc/{host:s})'
RFC5280_USAGE_MAP = {KEY_USAGE_SIG: 'digitalSignature',
KEY_USAGE_ENC: 'dataEncipherment'}
class KEMLdap(iSecLdap):
@property
def keysbase(self):
return '%s,%s' % (IPA_REL_BASE_DN, self.basedn)
def _encode_int(self, i):
I = hex(i).rstrip("L").lstrip("0x")
return base64url_encode(unhexlify((len(I) % 2) * '0' + I))
def _parse_public_key(self, ipa_public_key):
public_key = serialization.load_der_public_key(ipa_public_key,
default_backend())
num = public_key.public_numbers()
if isinstance(num, rsa.RSAPublicNumbers):
return {'kty': 'RSA',
'e': self._encode_int(num.e),
'n': self._encode_int(num.n)}
elif isinstance(num, ec.EllipticCurvePublicNumbers):
if num.curve.name == 'secp256r1':
curve = 'P-256'
elif num.curve.name == 'secp384r1':
curve = 'P-384'
elif num.curve.name == 'secp521r1':
curve = 'P-521'
else:
raise TypeError('Unsupported Elliptic Curve')
return {'kty': 'EC',
'crv': curve,
'x': self._encode_int(num.x),
'y': self._encode_int(num.y)}
else:
raise TypeError('Unknown Public Key type')
def get_key(self, usage, principal):
conn = self.connect()
scope = ldap.SCOPE_SUBTREE
ldap_filter = self.build_filter(IPA_KEYS_QUERY,
{'usage': RFC5280_USAGE_MAP[usage],
'princ': principal})
r = conn.search_s(self.keysbase, scope, ldap_filter)
if len(r) != 1:
raise ValueError("Incorrect number of results (%d) searching for"
"public key for %s" % (len(r), principal))
ipa_public_key = r[0][1]['ipaPublicKey'][0]
jwk = self._parse_public_key(ipa_public_key)
jwk['use'] = KEY_USAGE_MAP[usage]
return json_encode(jwk)
def check_host_keys(self, host):
conn = self.connect()
scope = ldap.SCOPE_SUBTREE
ldap_filter = self.build_filter(IPA_CHECK_QUERY, {'host': host})
r = conn.search_s(self.keysbase, scope, ldap_filter)
if len(r) != 1:
raise ValueError("Incorrect number of results (%d) searching for"
"public key for %s" % (len(r), host))
def _format_public_key(self, key):
if isinstance(key, str):
jwkey = json_decode(key)
if 'kty' not in jwkey:
raise ValueError('Invalid key, missing "kty" attribute')
if jwkey['kty'] == 'RSA':
pubnum = rsa.RSAPublicNumbers(jwkey['e'], jwkey['n'])
pubkey = pubnum.public_key(default_backend())
elif jwkey['kty'] == 'EC':
if jwkey['crv'] == 'P-256':
curve = ec.SECP256R1
elif jwkey['crv'] == 'P-384':
curve = ec.SECP384R1
elif jwkey['crv'] == 'P-521':
curve = ec.SECP521R1
else:
raise TypeError('Unsupported Elliptic Curve')
pubnum = ec.EllipticCurvePublicNumbers(
jwkey['x'], jwkey['y'], curve)
pubkey = pubnum.public_key(default_backend())
else:
raise ValueError('Unknown key type: %s' % jwkey['kty'])
elif isinstance(key, rsa.RSAPublicKey):
pubkey = key
elif isinstance(key, ec.EllipticCurvePublicKey):
pubkey = key
else:
raise TypeError('Unknown key type: %s' % type(key))
return pubkey.public_bytes(
encoding=serialization.Encoding.DER,
format=serialization.PublicFormat.SubjectPublicKeyInfo)
def set_key(self, usage, principal, key):
"""
Write key for the host or service.
Service keys are nested one level beneath the 'cn=custodia'
container, in the 'cn=<servicename>' container; this allows
fine-grained control over key management permissions for
specific services.
The container is assumed to exist.
"""
public_key = self._format_public_key(key)
conn = self.connect()
servicename, host = principal.split('@')[0].split('/')
name = '%s/%s' % (KEY_USAGE_MAP[usage], host)
service_rdn = ('cn', servicename) if servicename != 'host' else DN()
dn = str(DN(('cn', name), service_rdn, self.keysbase))
try:
mods = [('objectClass', [b'nsContainer',
b'ipaKeyPolicy',
b'ipaPublicKeyObject',
b'groupOfPrincipals']),
('cn', name.encode('utf-8')),
('ipaKeyUsage', RFC5280_USAGE_MAP[usage].encode('utf-8')),
('memberPrincipal', principal.encode('utf-8')),
('ipaPublicKey', public_key)]
conn.add_s(dn, mods)
except ldap.ALREADY_EXISTS:
mods = [(ldap.MOD_REPLACE, 'ipaPublicKey', public_key)]
conn.modify_s(dn, mods)
def newServerKeys(path, keyid):
skey = JWK(generate='RSA', use='sig', kid=keyid)
ekey = JWK(generate='RSA', use='enc', kid=keyid)
with open(path, 'w') as f:
os.fchmod(f.fileno(), 0o600)
os.fchown(f.fileno(), 0, 0)
f.write('[%s,%s]' % (skey.export(), ekey.export()))
return [skey.get_op_key('verify'), ekey.get_op_key('encrypt')]
class IPAKEMKeys(KEMKeysStore):
"""A KEM Keys Store.
This is a store that holds public keys of registered
clients allowed to use KEM messages. It takes the form
of an authorizer merely for the purpose of attaching
itself to a 'request' so that later on the KEM Parser
can fetch the appropariate key to verify/decrypt an
incoming request and make the payload available.
The KEM Parser will actually perform additional
authorization checks in this case.
SimplePathAuthz is extended here as we want to attach the
store only to requests on paths we are configured to
manage.
"""
def __init__(self, config=None, ipaconf=paths.IPA_DEFAULT_CONF):
super(IPAKEMKeys, self).__init__(config)
conf = ConfigParser()
conf.read(ipaconf)
self.host = conf.get('global', 'host')
self.realm = conf.get('global', 'realm')
self.ldap_uri = config.get('ldap_uri', None)
if self.ldap_uri is None:
self.ldap_uri = conf.get('global', 'ldap_uri', raw=True)
self._server_keys = None
def find_key(self, kid, usage):
if kid is None:
raise TypeError('Key ID is None, should be a SPN')
conn = KEMLdap(self.ldap_uri)
return conn.get_key(usage, kid)
def generate_server_keys(self):
self.generate_keys('host')
def generate_keys(self, servicename):
principal = '%s/%s@%s' % (servicename, self.host, self.realm)
# Neutralize the key with read if any
self._server_keys = None
# Generate private key and store it
pubkeys = newServerKeys(self.config['server_keys'], principal)
# Store public key in LDAP
ldapconn = KEMLdap(self.ldap_uri)
ldapconn.set_key(KEY_USAGE_SIG, principal, pubkeys[0])
ldapconn.set_key(KEY_USAGE_ENC, principal, pubkeys[1])
@property
def server_keys(self):
if self._server_keys is None:
with open(self.config['server_keys']) as f:
jsonkeys = f.read()
dictkeys = json_decode(jsonkeys)
self._server_keys = (JWK(**dictkeys[KEY_USAGE_SIG]),
JWK(**dictkeys[KEY_USAGE_ENC]))
return self._server_keys
# Manual testing
if __name__ == '__main__':
IKK = IPAKEMKeys({'paths': '/',
'server_keys': '/etc/ipa/custodia/server.keys'})
IKK.generate_server_keys()
print(('SIG', IKK.server_keys[0].export_public()))
print(('ENC', IKK.server_keys[1].export_public()))
print(IKK.find_key('host/%s@%s' % (IKK.host, IKK.realm),
usage=KEY_USAGE_SIG))
print(IKK.find_key('host/%s@%s' % (IKK.host, IKK.realm),
usage=KEY_USAGE_ENC))
|
