X-Git-Url: https://git.svenne.dk/?p=public%2Fdnssec-swede-utility.git;a=blobdiff_plain;f=swede;h=cd212a4c38b5595c387f9b4e7f9d89e25898f34c;hp=60947eb7d2a1d7e5cccf7488de1fe562dcb048a3;hb=HEAD;hpb=6accad05d1a1c9d7fe307208b67d274125d0bea5 diff --git a/swede b/swede index 60947eb..cd212a4 100755 --- a/swede +++ b/swede @@ -1,6 +1,6 @@ -#!/usr/bin/python +#!/usr/bin/python2 -# 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 @@ -17,6 +17,8 @@ import sys import os +import os.path +import socket import unbound import re from M2Crypto import X509, SSL @@ -24,8 +26,11 @@ from binascii import a2b_hex, b2a_hex from hashlib import sha256, sha512 from ipaddr import IPv4Address, IPv6Address +check_ipv4=True +check_ipv6=True -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. """ @@ -53,11 +58,12 @@ def genTLSA(hostname, protocol, port, certificate, output='draft', usage=1, sele 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): + if not check_ipv4: return [] """Gets a list of A records for hostname, returns a list of ARecords""" try: records = getRecords(hostname, rrtype='A', secure=secure) @@ -73,6 +79,7 @@ def getA(hostname, secure=True): return ret def getAAAA(hostname, secure=True): + if not check_ipv6: return [] """Gets a list of A records for hostname, returns a list of AAAARecords""" try: records = getRecords(hostname, rrtype='AAAA', secure=secure) @@ -126,7 +133,22 @@ def getRecords(hostname, rrtype='A', secure=True): """Do a lookup of a name and a rrtype, returns a list of binary coded strings. Only queries for rr_class IN.""" global resolvconf ctx = unbound.ub_ctx() - ctx.add_ta_file('root.key') + if os.path.exists("root.key"): + ctx.add_ta_file('root.key') + elif os.path.exists("/etc/swede/root.key"): + ctx.add_ta_file('/etc/swede/root.key') + else: + print "Cannot find root.key, please move it to /etc/swede" + sys.exit() + + if os.path.exists("dlv.isc.org.key"): + ctx.set_option("dlv-anchor-file:", "dlv.isc.org.key") + elif os.path.exists("/etc/swede/dlv.isc.org.key"): + ctx.set_option("dlv-anchor-file:", "/etc/swede/dlv.isc.org.key") + else: + print "Cannot find dlv.isc.org.key, please move it to /etc/swede" + sys.exit() + # Use the local cache if resolvconf and os.path.isfile(resolvconf): ctx.resolvconf(resolvconf) @@ -169,7 +191,7 @@ def getHash(certificate, mtype): 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] != '.': @@ -179,9 +201,9 @@ def getTLSA(hostname, port=443, protocol='tcp', secure=True): 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) @@ -232,6 +254,28 @@ def verifyCertMatch(record, cert): 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. """ @@ -241,7 +285,7 @@ class TLSARecord: 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) @@ -251,10 +295,10 @@ class TLSARecord: 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): @@ -271,7 +315,7 @@ class TLSARecord: 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]: @@ -331,6 +375,7 @@ class AAAARecord: """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): @@ -356,16 +401,16 @@ class DNSLookupError(Exception): 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.add_argument('-4', dest='ipv4', action='store_true',help='use ipv4 networking only') - #parser.add_argument('-6', dest='ipv6', action='store_true',help='use ipv6 networking only') + parser.add_argument('-4', dest='ipv4', action='store_true',help='use ipv4 networking only') + parser.add_argument('-6', dest='ipv6', action='store_true',help='use ipv6 networking only') parser.add_argument('--insecure', action='store_true', default=False, help='Allow use of non-dnssec secured answers') parser.add_argument('--resolvconf', metavar='/PATH/TO/RESOLV.CONF', action='store', default='', help='Use a recursive resolver from resolv.conf') parser.add_argument('-v', '--version', action='version', version='%(prog)s v0.2', help='show version and exit') @@ -380,7 +425,7 @@ if __name__ == '__main__': 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).') @@ -388,6 +433,15 @@ if __name__ == '__main__': parser_create.add_argument('--mtype', '-m', action='store', type=int, default=1, choices=[0,1,2], help='The Matching Type of the Certificate for Association. \'0\' for Exact match, \'1\' for SHA-256 hash, \'2\' for SHA-512 (default: %(default)s).') args = parser.parse_args() + import pprint + pprint.pprint(args) + if args.ipv4 == True and args.ipv6 == True: + print "Cannot have only ipv4 and only ipv6 at the same time" + sys.exit() + elif args.ipv4 == True: + check_ipv6 = False + elif args.ipv6 == True: + check_ipv4 = False if args.host[-1] != '.': args.host += '.' @@ -416,8 +470,8 @@ if __name__ == '__main__': 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: @@ -440,7 +494,13 @@ if __name__ == '__main__': if not args.quiet: print 'Attempting to verify the record with the TLS service...' - addresses = getA(args.host, secure=secure) + if check_ipv4 and check_ipv6: + addresses = getA(args.host, secure=secure) + getAAAA(args.host, secure=secure) + elif check_ipv4: + addresses = getA(args.host, secure=secure) + else: + addresses = getAAAA(args.host, secure=secure) + for address in addresses: if not args.quiet: print 'Got the following IP: %s' % str(address) @@ -455,16 +515,31 @@ if __name__ == '__main__': 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 check_ipv6 and isinstance(address, AAAARecord): + sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM) + sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) + elif check_ipv4 and isinstance(address, ARecord): + sock = socket.socket(socket.AF_INET, 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): @@ -504,7 +579,13 @@ if __name__ == '__main__': 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 @@ -556,9 +637,15 @@ if __name__ == '__main__': 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) + if check_ipv4 and check_ipv6: + addresses = getA(args.host, secure=secure) + getAAAA(args.host, secure=secure) + elif check_ipv4: + addresses = getA(args.host, secure=secure) + else: + addresses = getAAAA(args.host, secure=secure) + except InsecureLookupException, e: print >> sys.stderr, str(e) sys.exit(1) @@ -568,11 +655,22 @@ if __name__ == '__main__': # 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 check_ipv6 and isinstance(address, AAAARecord): + sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM) + sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) + if check_ipv4 and isinstance(address, ARecord): + sock = socket.socket(socket.AF_INET, 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: @@ -604,6 +702,13 @@ if __name__ == '__main__': 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)