#!/usr/bin/python
-# swede - A tool to create DANE/TLSA (draft 15) records.
+# swede - A tool to create DANE/TLSA records.
# This tool is really simple and not foolproof, it doesn't check the CN in the
# Subject field of the certificate. It also doesn't check if the supplied
# certificate is a CA certificate if usage 1 is specified (or any other
import sys
import os
+import socket
import unbound
import re
from M2Crypto import X509, SSL
from ipaddr import IPv4Address, IPv6Address
-def genTLSA(hostname, protocol, port, certificate, output='draft', usage=1, selector=0, mtype=1):
+def genTLSA(hostname, protocol, port, certificate, output='generic', usage=1, selector=0, mtype=1):
"""This function generates a TLSARecord object using the data passed in the parameters,
it then validates the record and returns the RR as a string.
"""
record.isValid(raiseException=True)
- if output == 'draft':
- return record.getRecord(draft=True)
+ if output == 'generic':
+ return record.getRecord(generic=True)
return record.getRecord()
def getA(hostname, secure=True):
global resolvconf
ctx = unbound.ub_ctx()
ctx.add_ta_file('root.key')
+ ctx.set_option("dlv-anchor-file:", "dlv.isc.org.key")
# Use the local cache
if resolvconf and os.path.isfile(resolvconf):
ctx.resolvconf(resolvconf)
def getTLSA(hostname, port=443, protocol='tcp', secure=True):
"""
This function tries to do a secure lookup of the TLSA record.
- At the moment it requests the TYPE65468 record and parses it into a 'valid' TLSA record
+ At the moment it requests the TYPE52 record and parses it into a 'valid' TLSA record
It returns a list of TLSARecord objects
"""
if hostname[-1] != '.':
raise Exception('Error: unknown protocol: %s. Should be one of tcp, udp or sctp' % protocol)
try:
if port == '*':
- records = getRecords('*._%s.%s' % (protocol.lower(), hostname), rrtype=65468, secure=secure)
+ records = getRecords('*._%s.%s' % (protocol.lower(), hostname), rrtype=52, secure=secure)
else:
- records = getRecords('_%s._%s.%s' % (port, protocol.lower(), hostname), rrtype=65468, secure=secure)
+ records = getRecords('_%s._%s.%s' % (port, protocol.lower(), hostname), rrtype=52, secure=secure)
except InsecureLookupException, e:
print str(e)
sys.exit(1)
else:
return False
+def verifyCertNameWithHostName(cert, hostname, with_msg=False):
+ """Verify the name on the certificate with a hostname, we need this because we get the cert based on IP address and thusly cannot rely on M2Crypto to verify this"""
+ if not isinstance(cert, X509.X509):
+ return
+ if not isinstance(hostname, str):
+ return
+
+ if hostname[-1] == '.':
+ hostname = hostname[0:-1]
+
+ # Ugly string comparison to see if the name on the ee-cert matches with the name provided on the commandline
+ try:
+ altnames_on_cert = cert.get_ext('subjectAltName').get_value()
+ except:
+ altnames_on_cert = ''
+ if hostname in (str(cert.get_subject()) + altnames_on_cert):
+ return True
+ else:
+ if with_msg:
+ print 'WARNING: Name on the certificate (Subject: %s, SubjectAltName: %s) doesn\'t match requested hostname (%s).' % (str(cert.get_subject()), altnames_on_cert, hostname)
+ return False
+
class TLSARecord:
"""When instanciated, this class contains all the fields of a TLSA record.
"""
cert should be a hexidecimal string representing the certificate to be matched field
"""
try:
- self.rrtype = 65468 # TLSA provisional
+ self.rrtype = 52 # TLSA per https://www.iana.org/assignments/dns-parameters
self.rrclass = 1 # IN
self.name = str(name)
self.usage = int(usage)
except:
raise Exception('Invalid value passed, unable to create a TLSARecord')
- def getRecord(self, draft=False):
- """Returns the RR string of this TLSARecord, either in rfc (default) or draft format"""
- if draft:
- return '%s IN TYPE65468 \# %s %s%s%s%s' % (self.name, (len(self.cert)/2)+3 , self._toHex(self.usage), self._toHex(self.selector), self._toHex(self.mtype), self.cert)
+ def getRecord(self, generic=False):
+ """Returns the RR string of this TLSARecord, either in rfc (default) or generic format"""
+ if generic:
+ return '%s IN TYPE52 \# %s %s%s%s%s' % (self.name, (len(self.cert)/2)+3 , self._toHex(self.usage), self._toHex(self.selector), self._toHex(self.mtype), self.cert)
return '%s IN TLSA %s %s %s %s' % (self.name, self.usage, self.selector, self.mtype, self.cert)
def _toHex(self, val):
if self.getPort() != '*':
err.append('Port %s not a number' % self.getPort())
if not self.usage in [0,1,2,3]:
- err.append('Usage: invalid (%s is not one of 0, 1 or 2)' % self.usage)
+ err.append('Usage: invalid (%s is not one of 0, 1, 2 or 3)' % self.usage)
if not self.selector in [0,1]:
err.append('Selector: invalid (%s is not one of 0 or 1)' % self.selector)
if not self.mtype in [0,1,2]:
"""An object representing an AAAA Record (IPv6 address)"""
def __init__(self, hostname, address):
self.rrtype = 28
+ self.hostname = hostname
self.address = address
def __str__(self):
if __name__ == '__main__':
import argparse
# create the parser
- parser = argparse.ArgumentParser(description='Create and verify DANE records.', epilog='This tool has a few limitations: it only IPv4 for SSL connections.')
+ parser = argparse.ArgumentParser(description='Create and verify DANE records.', epilog='This tool has a few limitations')
subparsers = parser.add_subparsers(title='Functions', help='Available functions, see %(prog)s function -h for function-specific help')
- parser_verify = subparsers.add_parser('verify', help='Verify a TLSA record, exit 0 when all TLSA records are matched, exit 2 when a record does not match the received certificate, exit 1 on error.', epilog='Caveat: For TLSA validation, this program chases through the certificate chain offered by the server, not it\'s local certificates.')
+ parser_verify = subparsers.add_parser('verify', help='Verify a TLSA record, exit 0 when all TLSA records are matched, exit 2 when a record does not match the received certificate, exit 1 on error.', epilog='Caveat: For TLSA validation, this program chases through the certificate chain offered by the server, not its local certificates.')
parser_verify.set_defaults(function='verify')
parser_create = subparsers.add_parser('create', help='Create a TLSA record')
parser_create.set_defaults(function='create')
parser_create.add_argument('--port', '-p', action='store', type=int, default=443, help='The port where running TLS is located (default: %(default)s).')
parser_create.add_argument('--protocol', action='store', choices=['tcp','udp','sctp'], default='tcp', help='The protocol the TLS service is using (default: %(default)s).')
parser_create.add_argument('--certificate', '-c', help='The certificate used for the host. If certificate is empty, the certificate will be downloaded from the server')
- parser_create.add_argument('--output', '-o', action='store', default='draft', choices=['draft','rfc','both'], help='The type of output. Draft (private RRtype, 65468), RFC (TLSA) or both (default: %(default)s).')
+ parser_create.add_argument('--output', '-o', action='store', default='generic', choices=['generic','rfc','both'], help='The type of output. Generic (RFC 3597, TYPE52), RFC (TLSA) or both (default: %(default)s).')
# Usage of the certificate
parser_create.add_argument('--usage', '-u', action='store', type=int, default=1, choices=[0,1,2,3], help='The Usage of the Certificate for Association. \'0\' for CA, \'1\' for End Entity, \'2\' for trust-anchor, \'3\' for ONLY End-Entity match (default: %(default)s).')
if not args.quiet:
print 'Received the following record for name %s:' % record.name
print '\tUsage:\t\t\t\t%d (%s)' % (record.usage, {0:'CA Constraint', 1:'End-Entity Constraint + chain to CA', 2:'Trust Anchor', 3:'End-Entity'}.get(record.usage, 'INVALID'))
- print '\tSelector:\t\t\t%d (%s)' % (record.selector, {0:'Certificate', 1:'SubjectPublicKeyInfo'}.get(record.usage, 'INVALID'))
- print '\tMatching Type:\t\t\t%d (%s)' % (record.mtype, {0:'Full Certificate', 1:'SHA-256', 2:'SHA-512'}.get(record.usage, 'INVALID'))
+ print '\tSelector:\t\t\t%d (%s)' % (record.selector, {0:'Certificate', 1:'SubjectPublicKeyInfo'}.get(record.selector, 'INVALID'))
+ print '\tMatching Type:\t\t\t%d (%s)' % (record.mtype, {0:'Full Certificate', 1:'SHA-256', 2:'SHA-512'}.get(record.mtype, 'INVALID'))
print '\tCertificate for Association:\t%s' % record.cert
try:
if not args.quiet:
print 'Attempting to verify the record with the TLS service...'
- addresses = getA(args.host, secure=secure)
+ addresses = getA(args.host, secure=secure) + getAAAA(args.host, secure=secure)
for address in addresses:
if not args.quiet:
print 'Got the following IP: %s' % str(address)
sys.exit(1)
# Don't error when the verification fails in the SSL handshake
ctx.set_verify(SSL.verify_none, depth=9)
- connection = SSL.Connection(ctx)
+ if isinstance(address, AAAARecord):
+ sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
+ sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+ else:
+ sock = None
+ connection = SSL.Connection(ctx, sock=sock)
try:
connection.connect((str(address), int(args.port)))
except SSL.Checker.WrongHost, e:
# The name on the remote cert doesn't match the hostname because we connect on IP, not hostname (as we want secure lookup)
pass
+ except socket.error, e:
+ print 'Cannot connect to %s: %s' % (address, str(e))
+ continue
chain = connection.get_peer_cert_chain()
verify_result = connection.get_verify_result()
# Good, now let's verify
+ if not verifyCertNameWithHostName(cert=chain[0], hostname=str(args.host), with_msg=True):
+ # The name on the cert doesn't match the hostname... we don't verify the TLSA record
+ print 'Not checking the TLSA record.'
+ continue
if record.usage == 1: # End-host cert
cert = chain[0]
if verifyCertMatch(record, cert):
elif record.usage == 2: # Usage 2, use the cert in the record as trust anchor
#FIXME: doesnt comply to the spec
matched = False
+ previous_issuer = None
for cert in chain:
+ if previous_issuer:
+ if not str(previous_issuer) == str(cert.get_subject()): # The chain cannot be valid
+ print "FAIL: Certificates don't chain"
+ break
+ previous_issuer = cert.get_issuer()
if verifyCertMatch(record, cert):
matched = True
continue
input_ok = True
except:
sys.stdout.write('Port %s not numerical or within correct range (1 <= port <= 65535), try again (hit enter for default 443): ' % user_input)
- # Get the A records for the host
+ # Get the address records for the host
try:
- addresses = getA(args.host, secure=secure)
+ addresses = getA(args.host, secure=secure) + getAAAA(args.host, secure=secure)
except InsecureLookupException, e:
print >> sys.stderr, str(e)
sys.exit(1)
# We do the certificate handling here, as M2Crypto keeps segfaulting when try to do stuff with the cert if we don't
ctx = SSL.Context()
ctx.set_verify(SSL.verify_none, depth=9)
- connection = SSL.Connection(ctx)
+ if isinstance(address, AAAARecord):
+ sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
+ sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+ else:
+ sock = None
+ connection = SSL.Connection(ctx, sock=sock)
try:
connection.connect((str(address), int(connection_port)))
except SSL.Checker.WrongHost:
pass
+ except socket.error, e:
+ print 'Cannot connect to %s: %s' % (address, str(e))
+ continue
chain = connection.get_peer_cert_chain()
for chaincert in chain:
else:
print genTLSA(args.host, args.protocol, args.port, cert, args.output, args.usage, args.selector, args.mtype)
+ # Clear the cert from memory (to stop M2Crypto from segfaulting)
+ # And cleanup the connection and context
+ cert=None
+ connection.clear()
+ connection.close()
+ ctx.close()
+
else: # Pass the path to the certificate to the genTLSA function
if args.output == 'both':
print genTLSA(args.host, args.protocol, args.port, args.certificate, 'draft', args.usage, args.selector, args.mtype)
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