commit df784323d0da737755def4015840d118e3c8e595 Author: Arturo Filastò art@fuffa.org Date: Tue Nov 20 22:29:00 2012 +0100

Add test that detects censorship in HTTP pages based on HTTP body length --- nettests/core/http_body_length.py | 90 +++++++++++++++++++++++++++++++++++++ 1 files changed, 90 insertions(+), 0 deletions(-)

diff --git a/nettests/core/http_body_length.py b/nettests/core/http_body_length.py new file mode 100644 index 0000000..7c5b0d2 --- /dev/null +++ b/nettests/core/http_body_length.py @@ -0,0 +1,90 @@ +# -*- encoding: utf-8 -*- +# +# :authors: Arturo Filastò +# :licence: see LICENSE + +from twisted.internet import defer +from twisted.python import usage +from ooni.templates import httpt + +class UsageOptions(usage.Options): + optParameters = [ + ['url', 'u', None, 'Specify a single URL to test.'], + ['factor', 'f', 0.8, 'What factor should be used for triggering censorship (0.8 == 80%)'] + ] + +class HTTPBodyLength(httpt.HTTPTest): + """ + Performs a two GET requests to the set of sites to be tested for + censorship, one over a known good control channel (Tor), the other over the + test network. + We then look at the response body lengths and see if the control response + differs from the experiment response by a certain factor. + """ + name = "HTTP Body length test" + author = "Arturo Filastò" + version = "0.1" + + usageOptions = UsageOptions + + inputFile = ['file', 'f', None, + 'List of URLS to perform GET and POST requests to'] + + # These values are used for determining censorship based on response body + # lengths + control_body_length = None + experiment_body_length = None + + def setUp(self): + """ + Check for inputs. + """ + if self.input: + self.url = self.input + elif self.localOptions['url']: + self.url = self.localOptions['url'] + else: + raise Exception("No input specified") + + self.factor = self.localOptions['factor'] + + def compare_body_lengths(self): + body_length_a = self.control_body_length + body_length_b = self.experiment_body_length + + rel = float(body_length_a)/float(body_length_b) + if rel > 1: + rel = 1/rel + + self.report['body_proportion'] = rel + self.report['factor'] = self.factor + if rel < self.factor: + self.report['censorship'] = True + else: + self.report['censorship'] = False + + def test_get(self): + def errback(failure): + log.err("There was an error while testing %s" % self.url) + log.exception(failure) + + def control_body(result): + self.control_body_length = len(result) + if self.experiment_body_length: + self.compare_body_lengths() + + def experiment_body(result): + self.experiment_body_length = len(result) + if self.control_body_length: + self.compare_body_lengths() + + dl = [] + experiment_request = self.doRequest(self.url, method="GET", + body_processor=experiment_body) + control_request = self.doRequest(self.url, method="GET", + use_tor=True, body_processor=control_body) + dl.append(experiment_request) + dl.append(control_request) + d = defer.DeferredList(dl) + return d +