commit e4f5b47d2eaf278adc1cd47505afa73b23b79f27 Merge: 40f5789 ee3911f Author: Arturo Filastò art@fuffa.org Date: Thu Sep 12 12:47:17 2013 +0200

Merge branch 'master' into feature/move_nettests

* master: Enforce str on IP address of backend. Change the default ports used by Tor.

data/ooniprobe.conf.sample | 4 ++-- ooni/nettests/blocking/dnsconsistency.py | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-)

diff --cc ooni/nettests/blocking/dnsconsistency.py index 3c88cd2,0000000..d883434 mode 100644,000000..100644 --- a/ooni/nettests/blocking/dnsconsistency.py +++ b/ooni/nettests/blocking/dnsconsistency.py @@@ -1,175 -1,0 +1,175 @@@ +# -*- encoding: utf-8 -*- +# +# dnsconsistency +# ************** +# +# The test reports censorship if the cardinality of the intersection of +# the query result set from the control server and the query result set +# from the experimental server is zero, which is to say, if the two sets +# have no matching results whatsoever. +# +# NOTE: This test frequently results in false positives due to GeoIP-based +# load balancing on major global sites such as google, facebook, and +# youtube, etc. +# +# :authors: Arturo Filastò, Isis Lovecruft +# :licence: see LICENSE + +import pdb + +from twisted.python import usage +from twisted.internet import defer + +from ooni.templates import dnst + +from ooni import nettest +from ooni.utils import log + +class UsageOptions(usage.Options): + optParameters = [['backend', 'b', '8.8.8.8:53', + 'The OONI backend that runs the DNS resolver'], + ['testresolvers', 'T', None, + 'File containing list of DNS resolvers to test against'], + ['testresolver', 't', None, + 'Specify a single test resolver to use for testing'] + ] + +class DNSConsistencyTest(dnst.DNSTest): + + name = "DNS Consistency" + description = "DNS censorship detection test" + version = "0.6" + authors = "Arturo Filastò, Isis Lovecruft" + requirements = None + + inputFile = ['file', 'f', None, + 'Input file of list of hostnames to attempt to resolve'] + + requiredTestHelpers = {'backend': 'dns'} + + usageOptions = UsageOptions + requiredOptions = ['backend', 'file'] + + def setUp(self): + if (not self.localOptions['testresolvers'] and \ + not self.localOptions['testresolver']): + raise usage.UsageError("You did not specify a testresolver") + + elif self.localOptions['testresolvers']: + test_resolvers_file = self.localOptions['testresolvers'] + + elif self.localOptions['testresolver']: + self.test_resolvers = [self.localOptions['testresolver']] + + try: + with open(test_resolvers_file) as f: + self.test_resolvers = [x.split('#')[0].strip() for x in f.readlines()] + self.report['test_resolvers'] = self.test_resolvers + f.close() + + except IOError, e: + log.exception(e) + raise usage.UsageError("Invalid test resolvers file") + + except NameError: + log.debug("No test resolver file configured") + + dns_ip, dns_port = self.localOptions['backend'].split(':') - self.control_dns_server = (dns_ip, int(dns_port)) ++ self.control_dns_server = (str(dns_ip), int(dns_port)) + + self.report['control_resolver'] = self.control_dns_server + + @defer.inlineCallbacks + def test_a_lookup(self): + """ + We perform an A lookup on the DNS test servers for the domains to be + tested and an A lookup on the known good DNS server. + + We then compare the results from test_resolvers and that from + control_resolver and see if the match up. + If they match up then no censorship is happening (tampering: false). + + If they do not we do a reverse lookup (PTR) on the test_resolvers and + the control resolver for every IP address we got back and check to see + if anyone of them matches the control ones. + + If they do then we take not of the fact that censorship is probably not + happening (tampering: reverse-match). + + If they do not match then censorship is probably going on (tampering: + true). + """ + log.msg("Doing the test lookups on %s" % self.input) + list_of_ds = [] + hostname = self.input + + self.report['tampering'] = {} + + control_answers = yield self.performALookup(hostname, self.control_dns_server) + if not control_answers: + log.err("Got no response from control DNS server %s," \ + " perhaps the DNS resolver is down?" % self.control_dns_server[0]) + self.report['tampering'][self.control_dns_server] = 'no_answer' + return + + for test_resolver in self.test_resolvers: + log.msg("Testing resolver: %s" % test_resolver) + test_dns_server = (test_resolver, 53) + + try: + experiment_answers = yield self.performALookup(hostname, test_dns_server) + except Exception, e: + log.err("Problem performing the DNS lookup") + log.exception(e) + self.report['tampering'][test_resolver] = 'dns_lookup_error' + continue + + if not experiment_answers: + log.err("Got no response, perhaps the DNS resolver is down?") + self.report['tampering'][test_resolver] = 'no_answer' + continue + else: + log.debug("Got the following A lookup answers %s from %s" % (experiment_answers, test_resolver)) + + def lookup_details(): + """ + A closure useful for printing test details. + """ + log.msg("test resolver: %s" % test_resolver) + log.msg("experiment answers: %s" % experiment_answers) + log.msg("control answers: %s" % control_answers) + + log.debug("Comparing %s with %s" % (experiment_answers, control_answers)) + if set(experiment_answers) & set(control_answers): + lookup_details() + log.msg("tampering: false") + self.report['tampering'][test_resolver] = False + else: + log.msg("Trying to do reverse lookup") + + experiment_reverse = yield self.performPTRLookup(experiment_answers[0], test_dns_server) + control_reverse = yield self.performPTRLookup(control_answers[0], self.control_dns_server) + + if experiment_reverse == control_reverse: + log.msg("Further testing has eliminated false positives") + lookup_details() + log.msg("tampering: reverse_match") + self.report['tampering'][test_resolver] = 'reverse_match' + else: + log.msg("Reverse lookups do not match") + lookup_details() + log.msg("tampering: true") + self.report['tampering'][test_resolver] = True + + def inputProcessor(self, filename=None): + """ + This inputProcessor extracts domain names from urls + """ + log.debug("Running dnsconsistency default processor") + if filename: + fp = open(filename) + for x in fp.readlines(): + yield x.strip().split('//')[-1].split('/')[0] + fp.close() + else: + pass