commit 70ecad5372fabadb5ca3d66c5c4a2b4835542921 Merge: 9dbe984 bcb2794 Author: Arturo Filastò <art@fuffa.org> Date: Thu Feb 7 14:18:54 2013 +0100 Merge branch 'master' into dnstamper-dnsconsistency * master: Fix typo in dnstamper test example docs Properly handle errors when DNS lookups Fix typo in test writing documentation Conflicts: docs/source/tests/dnsconsistency.rst docs/source/tests/dnsconsistency.rst | 2 +- docs/source/writing_tests.rst | 4 ++-- nettests/blocking/dnsconsistency.py | 9 ++++++++- 3 files changed, 11 insertions(+), 4 deletions(-) diff --cc docs/source/tests/dnsconsistency.rst index 8a413bf,0000000..673661c mode 100644,000000..100644 --- a/docs/source/tests/dnsconsistency.rst +++ b/docs/source/tests/dnsconsistency.rst @@@ -1,180 -1,0 +1,180 @@@ +Details +======= + +*Test Name*: DNS Consistency (Ex DNS Tamper) + +*Current version*: 0.4 + +*NetTest*: DNS Consistency Test (https://gitweb.torproject.org/ooni-probe.git/blob/HEAD:/nettests/blocking/dn...) + +*Test Helper*: DNS Test Helper (https://gitweb.torproject.org/ooni-probe.git/blob/HEAD:/oonib/testhelpers/dn...) + +*Test Type*: Content Blocking + +*Requires Root*: No + +Description +=========== + +This test performs A queries to a set of test resolvers and a known good +control resolver. If the two results do not match it will perform a reverse DNS +lookup on the first A record address of both sets and check if they both +resolve to the same name. + +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. + +How to run the test +=================== + +`./bin/ooniprobe nettests/core/dnsconsistency.py [-t <test resolvers>|-T <test resolver file>-f <input file> -b IP:PORT` + +*test resolvers* is a single test resolver (IP address) + +*test resolvers file* is a file containing the IP addresses of the resolvers to test for censorship, one per line. + +*input file* is a file containing hostnames or urls to check for tampering. + +*IP:PORT* is the address of the known good "control" resolver. + +Sample report +============= + +From running: - `./bin/ooniprobe nettests/core/dnsconsistency.py -t test_inputs/dns_tamper_test_resolvers.txt -f test_inputs/http_host_file.txt` ++`./bin/ooniprobe nettests/core/dnsconsistency.py -T test_inputs/dns_tamper_test_resolvers.txt -f test_inputs/http_host_file.txt` + +:: + + ########################################### + # OONI Probe Report for DNS tamper test + # Thu Nov 29 12:17:19 2012 + ########################################### + --- + options: + collector: null + help: 0 + logfile: null + pcapfile: null + reportfile: null + resume: 0 + subargs: [-t, 8.8.8.8, -f, test_inputs/dns_tamper_file.txt] + test: nettests/blocking/dnsconsistency.py + probe_asn: null + probe_cc: null + probe_ip: 127.0.0.1 + software_name: ooniprobe + software_version: 0.0.7.1-alpha + start_time: 1354184239.0 + test_name: DNS tamper + test_version: '0.4' + ... + --- + input: torproject.org + report: + control_resolver: &id001 [8.8.8.8, 53] + queries: + - addrs: [86.59.30.40, 38.229.72.14, 38.229.72.16, 82.195.75.101] + answers: + - [<RR name=torproject.org type=A class=IN ttl=91s auth=False>, <A address=86.59.30.40 + ttl=91>] + - [<RR name=torproject.org type=A class=IN ttl=91s auth=False>, <A address=38.229.72.14 + ttl=91>] + - [<RR name=torproject.org type=A class=IN ttl=91s auth=False>, <A address=38.229.72.16 + ttl=91>] + - [<RR name=torproject.org type=A class=IN ttl=91s auth=False>, <A address=82.195.75.101 + ttl=91>] + query: '[Query(''torproject.org'', 1, 1)]' + query_type: A + resolver: *id001 + - addrs: [86.59.30.40, 38.229.72.14, 38.229.72.16, 82.195.75.101] + answers: + - [<RR name=torproject.org type=A class=IN ttl=91s auth=False>, <A address=86.59.30.40 + ttl=91>] + - [<RR name=torproject.org type=A class=IN ttl=91s auth=False>, <A address=38.229.72.14 + ttl=91>] + - [<RR name=torproject.org type=A class=IN ttl=91s auth=False>, <A address=38.229.72.16 + ttl=91>] + - [<RR name=torproject.org type=A class=IN ttl=91s auth=False>, <A address=82.195.75.101 + ttl=91>] + query: '[Query(''torproject.org'', 1, 1)]' + query_type: A + resolver: [8.8.8.8, 53] + tampering: {8.8.8.8: false} + test_name: test_a_lookup + test_runtime: 0.0733950138092041 + test_started: 1354187839.508863 + ... + --- + input: google.com + report: + control_resolver: &id001 [8.8.8.8, 53] + queries: + - addrs: [173.194.69.100, 173.194.69.139, 173.194.69.113, 173.194.69.101, 173.194.69.138, + 173.194.69.102] + answers: + - [<RR name=google.com type=A class=IN ttl=54s auth=False>, <A address=173.194.69.100 + ttl=54>] + - [<RR name=google.com type=A class=IN ttl=54s auth=False>, <A address=173.194.69.139 + ttl=54>] + - [<RR name=google.com type=A class=IN ttl=54s auth=False>, <A address=173.194.69.113 + ttl=54>] + - [<RR name=google.com type=A class=IN ttl=54s auth=False>, <A address=173.194.69.101 + ttl=54>] + - [<RR name=google.com type=A class=IN ttl=54s auth=False>, <A address=173.194.69.138 + ttl=54>] + - [<RR name=google.com type=A class=IN ttl=54s auth=False>, <A address=173.194.69.102 + ttl=54>] + query: '[Query(''google.com'', 1, 1)]' + query_type: A + resolver: *id001 + - addrs: [173.194.69.100, 173.194.69.139, 173.194.69.113, 173.194.69.101, 173.194.69.138, + 173.194.69.102] + answers: + - [<RR name=google.com type=A class=IN ttl=54s auth=False>, <A address=173.194.69.100 + ttl=54>] + - [<RR name=google.com type=A class=IN ttl=54s auth=False>, <A address=173.194.69.139 + ttl=54>] + - [<RR name=google.com type=A class=IN ttl=54s auth=False>, <A address=173.194.69.113 + ttl=54>] + - [<RR name=google.com type=A class=IN ttl=54s auth=False>, <A address=173.194.69.101 + ttl=54>] + - [<RR name=google.com type=A class=IN ttl=54s auth=False>, <A address=173.194.69.138 + ttl=54>] + - [<RR name=google.com type=A class=IN ttl=54s auth=False>, <A address=173.194.69.102 + ttl=54>] + query: '[Query(''google.com'', 1, 1)]' + query_type: A + resolver: [8.8.8.8, 53] + tampering: {8.8.8.8: false} + test_name: test_a_lookup + test_runtime: 0.08325004577636719 + test_started: 1354187839.51091 + ... + --- + input: measurementlab.net + report: + control_resolver: &id001 [8.8.8.8, 53] + queries: + - addrs: [72.249.86.184] + answers: + - [<RR name=measurementlab.net type=A class=IN ttl=600s auth=False>, <A address=72.249.86.184 + ttl=600>] + query: '[Query(''measurementlab.net'', 1, 1)]' + query_type: A + resolver: *id001 + - addrs: [72.249.86.184] + answers: + - [<RR name=measurementlab.net type=A class=IN ttl=600s auth=False>, <A address=72.249.86.184 + ttl=600>] + query: '[Query(''measurementlab.net'', 1, 1)]' + query_type: A + resolver: [8.8.8.8, 53] + tampering: {8.8.8.8: false} + test_name: test_a_lookup + test_runtime: 0.2565779685974121 + test_started: 1354187839.512434 + ... + +Notes: Query is the string representation of :class:twisted.names.dns.Query + diff --cc nettests/blocking/dnsconsistency.py index 6703478,0000000..7b6e7b9 mode 100644,000000..100644 --- a/nettests/blocking/dnsconsistency.py +++ b/nettests/blocking/dnsconsistency.py @@@ -1,166 -1,0 +1,173 @@@ +# -*- 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 = "0.5" + authors = "Arturo Filastò, Isis Lovecruft" + requirements = None + + inputFile = ['file', 'f', None, + 'Input file of list of hostnames to attempt to resolve'] + + 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.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) + - experiment_answers = yield self.performALookup(hostname, test_dns_server) ++ 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