Source code for dns_sprockets_lib.validators.nsec3_chain

'''
nsec3_chain - Zone test: Nsec3Chain

.. Copyright (c) 2015 Neustar, Inc. All rights reserved.
.. See COPYRIGHT.txt for full notice.  See LICENSE.txt for terms and conditions.
'''


import base64

import dns.rdtypes.ANY.NSEC3

import dns_sprockets_lib.validators as validators


[docs]class Nsec3Chain(validators.ZoneTest): # pylint: disable=too-few-public-methods ''' Checks for valid NSEC3 chain. ''' TEST_DNSSECTYPE = 'NSEC3'
[docs] def run(self, context, suggested_tested): # Get all the NSEC3's in a name[0].upper() -> nsec3_rdata dict: nsec3_dict = dict( [(nsec3[0].labels[0].upper(), nsec3[1][0]) for nsec3 in context.zone_obj.iterate_rdatasets('NSEC3')]) # Check there's at least one NSEC3: if len(nsec3_dict) == 0: return (suggested_tested, 'No NSEC3s in the zone') result = None # Pick any one as the first, and follow the chain, should end up on same # one after len(nsec3_dict) hops. Also keep track of number of times # an NSEC3's next value is less than the name[0]; it should be exactly # one, for a correctly constructed chain: for (first_name, nsec3_rdata) in nsec3_dict.iteritems(): break # pylint: disable=undefined-loop-variable name = first_name next_less_than_name_cnt = 0 for _ in xrange(len(nsec3_dict)): # Encode the next name: next_name = base64.b32encode(nsec3_rdata.next).translate( dns.rdtypes.ANY.NSEC3.b32_normal_to_hex) # Count number of times NSEC3's next is less than name: if next_name < name: next_less_than_name_cnt += 1 # Make sure there's an NSEC3 for the next name: if next_name not in nsec3_dict: result = 'Chain broken at %s (next=%s doesn\'t exist)' % ( name, next_name) break name = next_name nsec3_rdata = nsec3_dict[name] if not result and name != first_name: result = 'Chain walk didn\'t end up on start item' if not result and next_less_than_name_cnt != 1: result = 'Chain not ordered correctly' return (suggested_tested, result) # end of file