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verify payment requests with tlslite and pyasn1 (pure python) instead of m2Crypto

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This commit is contained in:
ThomasV
2014-06-10 14:32:17 +02:00
parent 440f972fd3
commit 958f764dae
2 changed files with 302 additions and 75 deletions
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163
lib/paymentrequest.py
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@@ -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