commit 958f764daeee14327bcc3474aaf6e03b2db05cdf
parent 440f972fd3eab0cac7f486e1de8e028a34df3fb9
Author: ThomasV <thomasv@gitorious>
Date: Tue, 10 Jun 2014 14:32:17 +0200
verify payment requests with tlslite and pyasn1 (pure python) instead of m2Crypto
Diffstat:
| M | lib/paymentrequest.py | | | 163 | +++++++++++++++++++++++++++++++++++++++++++------------------------------------ |
| A | lib/x509.py | | | 214 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
2 files changed, 302 insertions(+), 75 deletions(-)
diff --git a/lib/paymentrequest.py b/lib/paymentrequest.py
@@ -1,3 +1,22 @@
+#!/usr/bin/env python
+#
+# Electrum - lightweight Bitcoin client
+# Copyright (C) 2014 Thomas Voegtlin
+#
+# 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 hashlib
import httplib
import os.path
@@ -24,6 +43,7 @@ except ImportError:
import bitcoin
import util
import transaction
+import x509
REQUEST_HEADERS = {'Accept': 'application/bitcoin-paymentrequest', 'User-Agent': 'Electrum'}
@@ -39,12 +59,10 @@ PR_ERROR = 4 # could not parse
ca_list = {}
+
+
+
def load_certificates():
- try:
- from M2Crypto import X509
- except:
- print_error("ERROR: Could not import M2Crypto")
- return False
ca_path = os.path.expanduser("~/.electrum/ca/ca-bundle.crt")
try:
@@ -62,14 +80,20 @@ def load_certificates():
else:
c += line
if line == "-----END CERTIFICATE-----\n":
- x = X509.load_cert_string(c)
- ca_list[x.get_fingerprint()] = x
+ x = x509.X509()
+ try:
+ x.parse(c)
+ except Exception as e:
+ print "cannot parse cert:", e
+ ca_list[x.getFingerprint()] = x
ca_f.close()
+ util.print_error("%d certificates"%len(ca_list))
return True
load_certificates()
+
class PaymentRequest:
def __init__(self, config):
self.config = config
@@ -130,19 +154,13 @@ class PaymentRequest:
def verify(self):
- try:
- from M2Crypto import X509
- except:
- self.error = "cannot import M2Crypto"
- return False
if not ca_list:
self.error = "Trusted certificate authorities list not found"
return False
paymntreq = self.data
- sig = paymntreq.signature
- if not sig:
+ if not paymntreq.signature:
self.error = "No signature"
return
@@ -150,86 +168,79 @@ class PaymentRequest:
cert.ParseFromString(paymntreq.pki_data)
cert_num = len(cert.certificate)
- x509_1 = X509.load_cert_der_string(cert.certificate[0])
- if self.domain != x509_1.get_subject().CN:
- validcert = False
- try:
- SANs = x509_1.get_ext("subjectAltName").get_value().split(",")
- for s in SANs:
- s = s.strip()
- if s.startswith("DNS:") and s[4:] == self.domain:
- validcert = True
- print "Match SAN DNS"
- elif s.startswith("IP:") and s[3:] == self.domain:
- validcert = True
- print "Match SAN IP"
- elif s.startswith("email:") and s[6:] == self.domain:
- validcert = True
- print "Match SAN email"
- except Exception, e:
- print "ERROR: No SAN data"
- if not validcert:
- ###TODO: check for wildcards
- self.error = "ERROR: Certificate Subject Domain Mismatch and SAN Mismatch"
- return
-
- x509 = []
- CA_OU = ''
-
- if cert_num > 1:
- for i in range(cert_num - 1):
- x509.append(X509.load_cert_der_string(cert.certificate[i+1]))
- if x509[i].check_ca() == 0:
+ x509_chain = []
+ for i in range(cert_num):
+ x = x509.X509()
+ x.parseBinary(bytearray(cert.certificate[i]))
+ x.slow_parse()
+ x509_chain.append(x)
+ if i == 0:
+ if not x.check_name(self.domain):
+ self.error = "Certificate Domain Mismatch"
+ return
+ else:
+ if not x.check_ca():
self.error = "ERROR: Supplied CA Certificate Error"
return
- for i in range(cert_num - 1):
- if i == 0:
- if x509_1.verify(x509[i].get_pubkey()) != 1:
- self.error = "ERROR: Certificate not Signed by Provided CA Certificate Chain"
- return
- else:
- if x509[i-1].verify(x509[i].get_pubkey()) != 1:
- self.error = "ERROR: CA Certificate not Signed by Provided CA Certificate Chain"
- return
-
- supplied_CA_fingerprint = x509[cert_num-2].get_fingerprint()
- supplied_CA_CN = x509[cert_num-2].get_subject().CN
- CA_match = False
- x = ca_list.get(supplied_CA_fingerprint)
- if x:
- CA_OU = x.get_subject().OU
- CA_match = True
- if x.get_subject().CN != supplied_CA_CN:
- print "ERROR: Trusted CA CN Mismatch; however CA has trusted fingerprint"
- print "Payment will continue with manual verification."
- else:
- print "ERROR: Supplied CA Not Found in Trusted CA Store."
- print "Payment will continue with manual verification."
- else:
+ if not cert_num > 1:
self.error = "ERROR: CA Certificate Chain Not Provided by Payment Processor"
return False
+ for i in range(1, cert_num):
+ x = x509_chain[i]
+ prev_x = x509_chain[i-1]
+
+ algo, sig, data = prev_x.extract_sig()
+ if algo.getComponentByName('algorithm') != x509.ALGO_RSA_SHA1:
+ self.error = "Algorithm not suported"
+ return
+
+ sig = bytearray(sig[5:])
+ pubkey = x.publicKey
+ verify = pubkey.hashAndVerify(sig, data)
+ if not verify:
+ self.error = "Certificate not Signed by Provided CA Certificate Chain"
+ return
+
+ ca = x509_chain[cert_num-1]
+ supplied_CA_fingerprint = ca.getFingerprint()
+ supplied_CA_names = ca.extract_names()
+ CA_OU = supplied_CA_names['OU']
+
+ x = ca_list.get(supplied_CA_fingerprint)
+ if x:
+ x.slow_parse()
+ names = x.extract_names()
+ CA_match = True
+ if names['CN'] != supplied_CA_names['CN']:
+ print "ERROR: Trusted CA CN Mismatch; however CA has trusted fingerprint"
+ print "Payment will continue with manual verification."
+ else:
+ CA_match = False
+
+ pubkey0 = x509_chain[0].publicKey
+ sig = paymntreq.signature
paymntreq.signature = ''
s = paymntreq.SerializeToString()
- pubkey_1 = x509_1.get_pubkey()
+ sigBytes = bytearray(sig)
+ msgBytes = bytearray(s)
if paymntreq.pki_type == "x509+sha256":
- pubkey_1.reset_context(md="sha256")
+ hashBytes = bytearray(hashlib.sha256(msgBytes).digest())
+ prefixBytes = bytearray([0x30,0x31,0x30,0x0d,0x06,0x09,0x60,0x86,0x48,0x01,0x65,0x03,0x04,0x02,0x01,0x05,0x00,0x04,0x20])
+ verify = pubkey0.verify(sigBytes, prefixBytes + hashBytes)
elif paymntreq.pki_type == "x509+sha1":
- pubkey_1.reset_context(md="sha1")
+ verify = pubkey0.hashAndVerify(sigBytes, msgBytes)
else:
self.error = "ERROR: Unsupported PKI Type for Message Signature"
return False
- pubkey_1.verify_init()
- pubkey_1.verify_update(s)
- if pubkey_1.verify_final(sig) != 1:
+ if not verify:
self.error = "ERROR: Invalid Signature for Payment Request Data"
return False
### SIG Verified
-
self.details = pay_det = paymentrequest_pb2.PaymentDetails()
self.details.ParseFromString(paymntreq.serialized_payment_details)
@@ -241,6 +252,8 @@ class PaymentRequest:
if CA_match:
self.status = 'Signed by Trusted CA:\n' + CA_OU
+ else:
+ self.status = "Supplied CA Not Found in Trusted CA Store."
self.payment_url = self.details.payment_url
diff --git a/lib/x509.py b/lib/x509.py
@@ -0,0 +1,214 @@
+#!/usr/bin/env python
+#
+# Electrum - lightweight Bitcoin client
+# Copyright (C) 2014 Thomas Voegtlin
+#
+# 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/>.
+
+
+from datetime import datetime, timedelta
+
+try:
+ import pyasn1
+except ImportError:
+ sys.exit("Error: pyasn1 does not seem to be installed. Try 'sudo pip install pyasn1'")
+
+try:
+ import tlslite
+except ImportError:
+ sys.exit("Error: tlslite does not seem to be installed. Try 'sudo pip install tlslite'")
+
+
+
+from pyasn1.codec.der import decoder, encoder
+from pyasn1.type.univ import Any, ObjectIdentifier, OctetString
+from pyasn1.type.char import BMPString, IA5String, UTF8String
+from pyasn1.type.useful import GeneralizedTime
+from pyasn1_modules.rfc2459 import (Certificate, DirectoryString,
+ SubjectAltName, GeneralNames,
+ GeneralName)
+from pyasn1_modules.rfc2459 import id_ce_subjectAltName as SUBJECT_ALT_NAME
+from pyasn1_modules.rfc2459 import id_at_commonName as COMMON_NAME
+from pyasn1_modules.rfc2459 import id_at_organizationalUnitName as OU_NAME
+from pyasn1_modules.rfc2459 import id_ce_basicConstraints, BasicConstraints
+XMPP_ADDR = ObjectIdentifier('1.3.6.1.5.5.7.8.5')
+SRV_NAME = ObjectIdentifier('1.3.6.1.5.5.7.8.7')
+ALGO_RSA_SHA1 = ObjectIdentifier('1.2.840.113549.1.1.5')
+
+
+class CertificateError(Exception):
+ pass
+
+def decode_str(data):
+ encoding = 'utf-16-be' if isinstance(data, BMPString) else 'utf-8'
+ return bytes(data).decode(encoding)
+
+
+class X509(tlslite.X509):
+ """ Child class of tlslite.X509 that uses pyasn1 """
+
+ def slow_parse(self):
+ self.cert = decoder.decode(str(self.bytes), asn1Spec=Certificate())[0]
+ self.tbs = self.cert.getComponentByName('tbsCertificate')
+ self.subject = self.tbs.getComponentByName('subject')
+ self.extensions = self.tbs.getComponentByName('extensions') or []
+
+ def extract_names(self):
+ results = {'CN': None,
+ 'DNS': set(),
+ 'SRV': set(),
+ 'URI': set(),
+ 'XMPPAddr': set(),
+ 'OU': None,}
+
+ # Extract the CommonName(s) from the cert.
+ for rdnss in self.subject:
+ for rdns in rdnss:
+ for name in rdns:
+ oid = name.getComponentByName('type')
+ value = name.getComponentByName('value')
+
+ if oid == COMMON_NAME:
+ value = decoder.decode(value, asn1Spec=DirectoryString())[0]
+ value = decode_str(value.getComponent())
+ results['CN'] = value
+
+ elif oid == OU_NAME:
+ value = decoder.decode(value, asn1Spec=DirectoryString())[0]
+ value = decode_str(value.getComponent())
+ results['OU'] = value
+
+ # Extract the Subject Alternate Names (DNS, SRV, URI, XMPPAddr)
+ for extension in self.extensions:
+ oid = extension.getComponentByName('extnID')
+ if oid != SUBJECT_ALT_NAME:
+ continue
+
+ value = decoder.decode(extension.getComponentByName('extnValue'),
+ asn1Spec=OctetString())[0]
+ sa_names = decoder.decode(value, asn1Spec=SubjectAltName())[0]
+ for name in sa_names:
+ name_type = name.getName()
+ if name_type == 'dNSName':
+ results['DNS'].add(decode_str(name.getComponent()))
+ if name_type == 'uniformResourceIdentifier':
+ value = decode_str(name.getComponent())
+ if value.startswith('xmpp:'):
+ results['URI'].add(value[5:])
+ elif name_type == 'otherName':
+ name = name.getComponent()
+
+ oid = name.getComponentByName('type-id')
+ value = name.getComponentByName('value')
+
+ if oid == XMPP_ADDR:
+ value = decoder.decode(value, asn1Spec=UTF8String())[0]
+ results['XMPPAddr'].add(decode_str(value))
+ elif oid == SRV_NAME:
+ value = decoder.decode(value, asn1Spec=IA5String())[0]
+ results['SRV'].add(decode_str(value))
+ return results
+
+
+ def check_ca(self):
+ for extension in self.extensions:
+ oid = extension.getComponentByName('extnID')
+ if oid != id_ce_basicConstraints:
+ continue
+ value = decoder.decode(extension.getComponentByName('extnValue'),
+ asn1Spec=OctetString())[0]
+ constraints = decoder.decode(value, asn1Spec=BasicConstraints())[0]
+ return bool(constraints[0])
+
+ def extract_sig(self):
+ signature = self.cert.getComponentByName('signatureValue')
+ algorithm = self.cert.getComponentByName('signatureAlgorithm')
+ data = encoder.encode(self.tbs)
+ s = encoder.encode(signature)
+ return algorithm, s, data
+
+
+ def extract_pubkey(self):
+ pki = self.tbs.getComponentByName('subjectPublicKeyInfo')
+ algo = pki.getComponentByName('algorithm')
+ algorithm = algo.getComponentByName('algorithm')
+ parameters = algo.getComponentByName('parameters')
+ subjectPublicKey = pki.getComponentByName('subjectPublicKey')
+ return algorithm, parameters, encoder.encode(subjectPublicKey)
+
+
+ def extract_dates(self):
+ validity = self.tbs.getComponentByName('validity')
+ not_before = validity.getComponentByName('notBefore')
+ not_before = str(not_before.getComponent())
+ not_after = validity.getComponentByName('notAfter')
+ not_after = str(not_after.getComponent())
+ if isinstance(not_before, GeneralizedTime):
+ not_before = datetime.strptime(not_before, '%Y%m%d%H%M%SZ')
+ else:
+ not_before = datetime.strptime(not_before, '%y%m%d%H%M%SZ')
+ if isinstance(not_after, GeneralizedTime):
+ not_after = datetime.strptime(not_after, '%Y%m%d%H%M%SZ')
+ else:
+ not_after = datetime.strptime(not_after, '%y%m%d%H%M%SZ')
+ return not_before, not_after
+
+ def get_ttl(self):
+ not_before, not_after = self.extract_dates()
+ if not_after is None:
+ return None
+ return not_after - datetime.utcnow()
+
+ def check_name(self, expected):
+ not_before, not_after = self.extract_dates()
+ cert_names = self.extract_names()
+ now = datetime.utcnow()
+ if not_before > now:
+ raise CertificateError(
+ 'Certificate has not entered its valid date range.')
+ if not_after <= now:
+ raise CertificateError(
+ 'Certificate has expired.')
+ if '.' in expected:
+ expected_wild = expected[expected.index('.'):]
+ else:
+ expected_wild = expected
+ expected_srv = '_xmpp-client.%s' % expected
+ for name in cert_names['XMPPAddr']:
+ if name == expected:
+ return True
+ for name in cert_names['SRV']:
+ if name == expected_srv or name == expected:
+ return True
+ for name in cert_names['DNS']:
+ if name == expected:
+ return True
+ if name.startswith('*'):
+ if '.' in name:
+ name_wild = name[name.index('.'):]
+ else:
+ name_wild = name
+ if expected_wild == name_wild:
+ return True
+ for name in cert_names['URI']:
+ if name == expected:
+ return True
+ if cert_names['CN'] == expected:
+ return True
+ raise CertificateError(
+ 'Could not match certficate against hostname: %s' % expected)
+
+
+class X509CertChain(tlslite.X509CertChain):
+ pass
