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import subprocess
import json
import base64
import urllib
import urllib2
import struct
import sys
import hashlib
import ecdsa
publickeys = {
"https://ct.googleapis.com/pilot/":
"MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEfahLEimAoz2t01p3uMziiLOl/fHTD"
"M0YDOhBRuiBARsV4UvxG2LdNgoIGLrtCzWE0J5APC2em4JlvR8EEEFMoA==",
"https://127.0.0.1:8080/":
"MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE4qWq6afhBUi0OdcWUYhyJLNXTkGqQ9"
"PMS5lqoCgkV2h1ZvpNjBH2u8UbgcOQwqDo66z6BWQJGolozZYmNHE2kQ==",
"https://flimsy.ct.nordu.net/":
"MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE4qWq6afhBUi0OdcWUYhyJLNXTkGqQ9"
"PMS5lqoCgkV2h1ZvpNjBH2u8UbgcOQwqDo66z6BWQJGolozZYmNHE2kQ==",
}
def get_cert_info(s):
p = subprocess.Popen(
["openssl", "x509", "-noout", "-subject", "-issuer", "-inform", "der"],
stdin=subprocess.PIPE, stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
parsed = p.communicate(s)
if parsed[1]:
print "ERROR:", parsed[1]
sys.exit(1)
result = {}
for line in parsed[0].split("\n"):
(key, sep, value) = line.partition("=")
if sep == "=":
result[key] = value
return result
def get_certs_from_file(certfile):
certs = []
cert = ""
incert = False
for line in open(certfile):
line = line.strip()
if line == "-----BEGIN CERTIFICATE-----":
cert = ""
incert = True
elif line == "-----END CERTIFICATE-----":
certs.append(base64.decodestring(cert))
incert = False
elif incert:
cert += line
return certs
def get_root_cert(issuer):
accepted_certs = \
json.loads(open("googlelog-accepted-certs.txt").read())["certificates"]
root_cert = None
for accepted_cert in accepted_certs:
subject = get_cert_info(base64.decodestring(accepted_cert))["subject"]
if subject == issuer:
root_cert = base64.decodestring(accepted_cert)
return root_cert
def get_sth(baseurl):
result = urllib2.urlopen(baseurl + "ct/v1/get-sth").read()
return json.loads(result)
def get_proof_by_hash(baseurl, hash, tree_size):
try:
params = urllib.urlencode({"hash":base64.b64encode(hash),
"tree_size":tree_size})
result = \
urllib2.urlopen(baseurl + "ct/v1/get-proof-by-hash?" + params).read()
return json.loads(result)
except urllib2.HTTPError, e:
print "ERROR:", e.read()
sys.exit(1)
def tls_array(data, length_len):
length_bytes = struct.pack(">Q", len(data))[-length_len:]
return length_bytes + data
def unpack_tls_array(packed_data, length_len):
padded_length = ["\x00"] * 8
padded_length[-length_len:] = packed_data[:length_len]
(length,) = struct.unpack(">Q", "".join(padded_length))
unpacked_data = packed_data[length_len:length_len+length]
assert len(unpacked_data) == length, \
"data is only %d bytes long, but length is %d bytes" % \
(len(unpacked_data), length)
rest_data = packed_data[length_len+length:]
return (unpacked_data, rest_data)
def add_chain(baseurl, submission):
try:
return json.loads(urllib2.urlopen(baseurl + "ct/v1/add-chain",
json.dumps(submission)).read())
except urllib2.HTTPError, e:
print "ERROR:", e.read()
sys.exit(1)
def get_entries(baseurl, start, end):
try:
params = urllib.urlencode({"start":start, "end":end})
result = urllib2.urlopen(baseurl + "ct/v1/get-entries?" + params).read()
return json.loads(result)
except urllib2.HTTPError, e:
print "ERROR:", e.read()
sys.exit(1)
def decode_certificate_chain(packed_certchain):
(unpacked_certchain, rest) = unpack_tls_array(packed_certchain, 3)
assert len(rest) == 0
certs = []
while len(unpacked_certchain):
(cert, rest) = unpack_tls_array(unpacked_certchain, 3)
certs.append(cert)
unpacked_certchain = rest
return certs
def decode_signature(signature):
(hash_alg, signature_alg) = struct.unpack(">bb", signature[0:2])
(unpacked_signature, rest) = unpack_tls_array(signature[2:], 2)
assert rest == ""
return (hash_alg, signature_alg, unpacked_signature)
def check_signature(baseurl, leafcert, sct):
publickey = base64.decodestring(publickeys[baseurl])
calculated_logid = hashlib.sha256(publickey).digest()
received_logid = base64.decodestring(sct["id"])
assert calculated_logid == received_logid, \
"log id is incorrect:\n should be %s\n got %s" % \
(calculated_logid.encode("hex_codec"),
received_logid.encode("hex_codec"))
signature = base64.decodestring(sct["signature"])
version = struct.pack(">b", sct["sct_version"])
signature_type = struct.pack(">b", 0)
timestamp = struct.pack(">Q", sct["timestamp"])
entry_type = struct.pack(">H", 0)
signed_struct = version + signature_type + timestamp + \
entry_type + tls_array(leafcert, 3) + \
tls_array(base64.decodestring(sct["extensions"]), 2)
(hash_alg, signature_alg, unpacked_signature) = decode_signature(signature)
assert hash_alg == 4 # sha256
assert signature_alg == 3 # ecdsa
hash = hashlib.sha256()
hash.update(signed_struct)
vk = ecdsa.VerifyingKey.from_der(publickey)
vk.verify(unpacked_signature, signed_struct, hashfunc=hashlib.sha256,
sigdecode=ecdsa.util.sigdecode_der)
def pack_mtl(timestamp, leafcert):
entry_type = struct.pack(">H", 0)
extensions = ""
timestamped_entry = struct.pack(">Q", timestamp) + entry_type + \
tls_array(leafcert, 3) + tls_array(extensions, 2)
version = struct.pack(">b", 0)
leaf_type = struct.pack(">b", 0)
merkle_tree_leaf = version + leaf_type + timestamped_entry
return merkle_tree_leaf
def get_leaf_hash(merkle_tree_leaf):
leaf_hash = hashlib.sha256()
leaf_hash.update(struct.pack(">b", 0))
leaf_hash.update(merkle_tree_leaf)
return leaf_hash.digest()
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