tx509: use SKI and AKI to find parent certificate if it is missing - electrum - Electrum Bitcoin wallet
HTML git clone https://git.parazyd.org/electrum
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DIR Files
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---
DIR commit f82de35bd203e35316f6f245bf2f0cc0f9e0821d
DIR parent fbf56c9cfa56b17ba1aa6af7c25117257fe06462
HTML Author: ThomasV <thomasv@gitorious>
Date: Fri, 17 Apr 2015 12:30:52 +0200
x509: use SKI and AKI to find parent certificate if it is missing
Diffstat:
M lib/paymentrequest.py | 14 ++++++++------
M lib/x509.py | 108 ++++++++++++++++---------------
2 files changed, 65 insertions(+), 57 deletions(-)
---
DIR diff --git a/lib/paymentrequest.py b/lib/paymentrequest.py
t@@ -44,7 +44,7 @@ REQUEST_HEADERS = {'Accept': 'application/bitcoin-paymentrequest', 'User-Agent':
ACK_HEADERS = {'Content-Type':'application/bitcoin-payment','Accept':'application/bitcoin-paymentack','User-Agent':'Electrum'}
ca_path = requests.certs.where()
-ca_list = x509.load_certificates(ca_path)
+ca_list, ca_keyID = x509.load_certificates(ca_path)
# status of payment requests
t@@ -142,15 +142,17 @@ class PaymentRequest:
return False
# if the root CA is not supplied, add it to the chain
ca = x509_chain[cert_num-1]
- if ca.get_common_name() not in ca_list:
- x = ca_list.get(ca.get_issuer())
- if x:
- x509_chain.append(x)
+ if ca.getFingerprint() not in ca_list:
+ keyID = ca.get_issuer_keyID()
+ f = ca_keyID.get(keyID)
+ if f:
+ root = ca_list[f]
+ x509_chain.append(root)
else:
self.error = "Supplied CA Not Found in Trusted CA Store."
return False
# verify the chain of signatures
- cert_num = len(cert.certificate)
+ cert_num = len(x509_chain)
for i in range(1, cert_num):
x = x509_chain[i]
prev_x = x509_chain[i-1]
DIR diff --git a/lib/x509.py b/lib/x509.py
t@@ -50,9 +50,6 @@ PREFIX_RSA_SHA512 = bytearray([0x30,0x51,0x30,0x0d,0x06,0x09,0x60,0x86,0x48,0x01
class CertificateError(Exception):
pass
-def decode_str(data):
- encoding = 'utf-16-be' if isinstance(data, BMPString) else 'utf-8'
- return bytes(data).decode(encoding)
def decode_OID(s):
s = map(ord, s)
t@@ -69,33 +66,31 @@ def decode_OID(s):
return '.'.join(map(str,r))
+def asn1_get_children(der, i):
+ nodes = []
+ ii = asn1_node_first_child(der,i)
+ nodes.append(ii)
+ while ii[2]<i[2]:
+ ii = asn1_node_next(der,ii)
+ nodes.append(ii)
+ return nodes
+
+def asn1_get_sequence(s):
+ return map(lambda j: asn1_get_value(s, j), asn1_get_children(s, asn1_node_root(s)))
+
+def asn1_get_dict(der, i):
+ p = {}
+ for ii in asn1_get_children(der, i):
+ for iii in asn1_get_children(der, ii):
+ iiii = asn1_node_first_child(der, iii)
+ oid = decode_OID(asn1_get_value_of_type(der, iiii, 'OBJECT IDENTIFIER'))
+ iiii = asn1_node_next(der, iiii)
+ value = asn1_get_value(der, iiii)
+ p[oid] = value
+ return p
+
class X509(tlslite.X509):
- """Child class of tlslite.X509 that uses pyasn1 to parse cert
- information. Note: pyasn1 is a lot slower than tlslite, so we
- should try to do everything in tlslite.
- """
-
- def get_children(self, der, i):
- nodes = []
- ii = asn1_node_first_child(der,i)
- while True:
- nodes.append(ii)
- ii = asn1_node_next(der,ii)
- if ii[0] > i[2]:
- break
- return nodes
-
- def get_dict(self, der, i):
- p = {}
- for ii in self.get_children(der, i):
- for iii in self.get_children(der, ii):
- iiii = asn1_node_first_child(der, iii)
- oid = decode_OID(asn1_get_value_of_type(der, iiii, 'OBJECT IDENTIFIER'))
- iiii = asn1_node_next(der, iiii)
- value = asn1_get_value(der, iiii)
- p[oid] = value
- return p
def parseBinary(self, b):
t@@ -123,7 +118,7 @@ class X509(tlslite.X509):
# issuer
issuer = asn1_node_next(der, sig_algo)
- self.issuer = self.get_dict(der, issuer)
+ self.issuer = asn1_get_dict(der, issuer)
# validity
validity = asn1_node_next(der, issuer)
t@@ -134,26 +129,31 @@ class X509(tlslite.X509):
# subject
subject = asn1_node_next(der, validity)
- self.subject = self.get_dict(der, subject)
+ self.subject = asn1_get_dict(der, subject)
subject_pki = asn1_node_next(der, subject)
- # optional fields: issuer_uid, subject_uid, extensions
- i = subject_pki
+ # extensions
self.CA = False
- while True:
+ self.AKI = None
+ self.SKI = None
+ i = subject_pki
+ while i[2] < cert[2]:
i = asn1_node_next(der, i)
- if i[0] > cert[2]:
- break
- for ii in self.get_children(der, i):
- for iii in self.get_children(der, ii):
- iiii = asn1_node_first_child(der, iii)
- oid = decode_OID(asn1_get_value_of_type(der, iiii, 'OBJECT IDENTIFIER'))
- iiii = asn1_node_next(der, iiii)
- value = asn1_get_value(der, iiii)
- if oid == '2.5.29.19': # basic constraints
- self.CA = value
- else:
- pass
+ d = asn1_get_dict(der, i)
+ for oid, value in d.items():
+ if oid == '2.5.29.19':
+ # Basic Constraints
+ self.CA = bool(value)
+ elif oid == '2.5.29.14':
+ # Subject Key Identifier
+ r = asn1_node_root(value)
+ value = asn1_get_value_of_type(value, r, 'OCTET STRING')
+ self.SKI = value.encode('hex')
+ elif oid == '2.5.29.35':
+ # Authority Key Identifier
+ self.AKI = asn1_get_sequence(value)[0].encode('hex')
+ else:
+ pass
# cert signature
cert_sig_algo = asn1_node_next(der, cert)
t@@ -162,13 +162,16 @@ class X509(tlslite.X509):
cert_sig = asn1_node_next(der, cert_sig_algo)
self.signature = asn1_get_value(der, cert_sig)[1:]
+ def get_keyID(self):
+ # http://security.stackexchange.com/questions/72077/validating-an-ssl-certificate-chain-according-to-rfc-5280-am-i-understanding-th
+ return self.SKI if self.SKI else repr(self.subject)
+
+ def get_issuer_keyID(self):
+ return self.AKI if self.AKI else repr(self.issuer)
def get_common_name(self):
return self.subject.get('2.5.4.3', 'unknown')
- def get_issuer(self):
- return self.issuer.get('2.5.4.3', 'unknown')
-
def get_signature(self):
return self.cert_sig_algo, self.signature, self.data
t@@ -198,6 +201,7 @@ class X509CertChain(tlslite.X509CertChain):
@profiler
def load_certificates(ca_path):
ca_list = {}
+ ca_keyID = {}
with open(ca_path, 'r') as f:
s = f.read()
bList = tlslite.utils.pem.dePemList(s, "CERTIFICATE")
t@@ -206,10 +210,12 @@ def load_certificates(ca_path):
try:
x.parseBinary(b)
x.check_date()
- except Exception as e:
+ except BaseException as e:
util.print_error("cert error:", e)
continue
- ca_list[x.get_common_name()] = x
+ fp = x.getFingerprint()
+ ca_list[fp] = x
+ ca_keyID[x.get_keyID()] = fp
- return ca_list
+ return ca_list, ca_keyID