mirror of
https://github.com/theupdateframework/python-tuf
synced 2026-05-24 10:08:28 +00:00
dad9f9f11b
This adds to PR #799; please see that for details. In short, tests sometimes fail on slow test systems (primarily on AppVeyor) if we don't have long enough delays. Signed-off-by: Sebastien Awwad <sebastien.awwad@gmail.com>
327 lines
14 KiB
Python
Executable file
327 lines
14 KiB
Python
Executable file
#!/usr/bin/env python
|
|
|
|
# Copyright 2012 - 2017, New York University and the TUF contributors
|
|
# SPDX-License-Identifier: MIT OR Apache-2.0
|
|
|
|
"""
|
|
<Program Name>
|
|
test_slow_retrieval_attack.py
|
|
|
|
<Author>
|
|
Konstantin Andrianov.
|
|
|
|
<Started>
|
|
March 13, 2012.
|
|
|
|
April 5, 2014.
|
|
Refactored to use the 'unittest' module (test conditions in code, rather
|
|
than verifying text output), use pre-generated repository files, and
|
|
discontinue use of the old repository tools. Expanded comments and modified
|
|
previous setup. -vladimir.v.diaz
|
|
|
|
<Copyright>
|
|
See LICENSE-MIT OR LICENSE for licensing information.
|
|
|
|
<Purpose>
|
|
Simulate a slow retrieval attack, where an attacker is able to prevent clients
|
|
from receiving updates by responding to client requests so slowly that updates
|
|
never complete. Test cases included for two types of slow retrievals: data
|
|
that slowly trickles in, and data that is only returned after a long time
|
|
delay. TUF prevents slow retrieval attacks by ensuring the download rate
|
|
does not fall below a required rate (tuf.settings.MIN_AVERAGE_DOWNLOAD_SPEED).
|
|
|
|
Note: There is no difference between 'updates' and 'target' files.
|
|
|
|
# TODO: Consider additional tests for slow metadata download. Tests here only
|
|
use slow target download.
|
|
"""
|
|
|
|
# Help with Python 3 compatibility, where the print statement is a function, an
|
|
# implicit relative import is invalid, and the '/' operator performs true
|
|
# division. Example: print 'hello world' raises a 'SyntaxError' exception.
|
|
from __future__ import print_function
|
|
from __future__ import absolute_import
|
|
from __future__ import division
|
|
from __future__ import unicode_literals
|
|
|
|
import os
|
|
import sys
|
|
import tempfile
|
|
import random
|
|
import time
|
|
import shutil
|
|
import json
|
|
import subprocess
|
|
import logging
|
|
import sys
|
|
import unittest
|
|
|
|
import tuf.log
|
|
import tuf.client.updater as updater
|
|
import tuf.unittest_toolbox as unittest_toolbox
|
|
import tuf.repository_tool as repo_tool
|
|
import tuf.roledb
|
|
import tuf.keydb
|
|
|
|
import six
|
|
|
|
logger = logging.getLogger('tuf.test_slow_retrieval_attack')
|
|
repo_tool.disable_console_log_messages()
|
|
|
|
|
|
class TestSlowRetrievalAttack(unittest_toolbox.Modified_TestCase):
|
|
|
|
@classmethod
|
|
def setUpClass(cls):
|
|
# setUpClass() is called before any of the test cases are executed.
|
|
|
|
# Create a temporary directory to store the repository, metadata, and target
|
|
# files. 'temporary_directory' must be deleted in TearDownModule() so that
|
|
# temporary files are always removed, even when exceptions occur.
|
|
cls.temporary_directory = tempfile.mkdtemp(dir=os.getcwd())
|
|
cls.SERVER_PORT = random.randint(30000, 45000)
|
|
|
|
|
|
|
|
@classmethod
|
|
def tearDownClass(cls):
|
|
# tearDownModule() is called after all the test cases have run.
|
|
# http://docs.python.org/2/library/unittest.html#class-and-module-fixtures
|
|
|
|
# Remove the temporary repository directory, which should contain all the
|
|
# metadata, targets, and key files generated of all the test cases.
|
|
shutil.rmtree(cls.temporary_directory)
|
|
|
|
|
|
|
|
def _start_slow_server(self, mode):
|
|
# Launch a SimpleHTTPServer (serves files in the current directory).
|
|
# Test cases will request metadata and target files that have been
|
|
# pre-generated in 'tuf/tests/repository_data', which will be served by the
|
|
# SimpleHTTPServer launched here. The test cases of this unit test assume
|
|
# the pre-generated metadata files have a specific structure, such
|
|
# as a delegated role 'targets/role1', three target files, five key files,
|
|
# etc.
|
|
command = ['python', 'slow_retrieval_server.py', str(self.SERVER_PORT), mode]
|
|
server_process = subprocess.Popen(command, stderr=subprocess.PIPE)
|
|
logger.info('Slow Retrieval Server process started.')
|
|
logger.info('Server process id: '+str(server_process.pid))
|
|
logger.info('Serving on port: '+str(self.SERVER_PORT))
|
|
url = 'http://localhost:'+str(self.SERVER_PORT) + os.path.sep
|
|
|
|
# NOTE: Following error is raised if a delay is not long enough:
|
|
# <urlopen error [Errno 111] Connection refused>
|
|
# or, on Windows:
|
|
# Failed to establish a new connection: [Errno 111] Connection refused'
|
|
# 1s led to occasional failures in automated builds on AppVeyor, so
|
|
# increasing this to 3s, sadly.
|
|
time.sleep(3)
|
|
|
|
return server_process
|
|
|
|
|
|
|
|
def _stop_slow_server(self, server_process):
|
|
# Kill the SimpleHTTPServer process.
|
|
if server_process.returncode is None:
|
|
logger.info('Server process '+str(server_process.pid)+' terminated.')
|
|
server_process.kill()
|
|
|
|
|
|
|
|
def setUp(self):
|
|
# We are inheriting from custom class.
|
|
unittest_toolbox.Modified_TestCase.setUp(self)
|
|
|
|
self.repository_name = 'test_repository1'
|
|
|
|
# Copy the original repository files provided in the test folder so that
|
|
# any modifications made to repository files are restricted to the copies.
|
|
# The 'repository_data' directory is expected to exist in 'tuf/tests/'.
|
|
original_repository_files = os.path.join(os.getcwd(), 'repository_data')
|
|
temporary_repository_root = \
|
|
self.make_temp_directory(directory=self.temporary_directory)
|
|
|
|
# The original repository, keystore, and client directories will be copied
|
|
# for each test case.
|
|
original_repository = os.path.join(original_repository_files, 'repository')
|
|
original_client = os.path.join(original_repository_files, 'client')
|
|
original_keystore = os.path.join(original_repository_files, 'keystore')
|
|
|
|
# Save references to the often-needed client repository directories.
|
|
# Test cases need these references to access metadata and target files.
|
|
self.repository_directory = \
|
|
os.path.join(temporary_repository_root, 'repository')
|
|
self.client_directory = os.path.join(temporary_repository_root, 'client')
|
|
self.keystore_directory = os.path.join(temporary_repository_root, 'keystore')
|
|
|
|
# Copy the original 'repository', 'client', and 'keystore' directories
|
|
# to the temporary repository the test cases can use.
|
|
shutil.copytree(original_repository, self.repository_directory)
|
|
shutil.copytree(original_client, self.client_directory)
|
|
shutil.copytree(original_keystore, self.keystore_directory)
|
|
|
|
|
|
# Produce a longer target file than exists in the other test repository
|
|
# data, to provide for a long-duration slow attack. Then we'll write new
|
|
# top-level metadata that includes a hash over that file, and provide that
|
|
# metadata to the client as well.
|
|
|
|
# The slow retrieval server, in mode 2 (1 byte per second), will only
|
|
# sleep for a total of (target file size) seconds. Add a target file
|
|
# that contains sufficient number of bytes to trigger a slow retrieval
|
|
# error. A transfer should not be permitted to take 1 second per byte
|
|
# transferred. Because this test is currently expected to fail, I'm
|
|
# limiting the size to 10 bytes (10 seconds) to avoid expected testing
|
|
# delays.... Consider increasing again after fix, to, e.g. 400.
|
|
total_bytes = 10
|
|
|
|
repository = repo_tool.load_repository(self.repository_directory)
|
|
file1_filepath = os.path.join(self.repository_directory, 'targets',
|
|
'file1.txt')
|
|
with open(file1_filepath, 'wb') as file_object:
|
|
data = 'a' * int(round(total_bytes))
|
|
file_object.write(data.encode('utf-8'))
|
|
|
|
key_file = os.path.join(self.keystore_directory, 'timestamp_key')
|
|
timestamp_private = repo_tool.import_ed25519_privatekey_from_file(key_file,
|
|
'password')
|
|
key_file = os.path.join(self.keystore_directory, 'snapshot_key')
|
|
snapshot_private = repo_tool.import_ed25519_privatekey_from_file(key_file,
|
|
'password')
|
|
key_file = os.path.join(self.keystore_directory, 'targets_key')
|
|
targets_private = repo_tool.import_ed25519_privatekey_from_file(key_file,
|
|
'password')
|
|
|
|
repository.targets.load_signing_key(targets_private)
|
|
repository.snapshot.load_signing_key(snapshot_private)
|
|
repository.timestamp.load_signing_key(timestamp_private)
|
|
|
|
repository.writeall()
|
|
|
|
# Move the staged metadata to the "live" metadata.
|
|
shutil.rmtree(os.path.join(self.repository_directory, 'metadata'))
|
|
shutil.copytree(os.path.join(self.repository_directory, 'metadata.staged'),
|
|
os.path.join(self.repository_directory, 'metadata'))
|
|
|
|
# Since we've changed the repository metadata in this setup (by lengthening
|
|
# a target file and then writing new metadata), we also have to update the
|
|
# client metadata to get to the expected initial state, where the client
|
|
# knows the right target info (and so expects the right, longer target
|
|
# length.
|
|
# We'll skip using updater.refresh since we don't have a server running,
|
|
# and we'll update the metadata locally, manually.
|
|
shutil.rmtree(os.path.join(
|
|
self.client_directory, self.repository_name, 'metadata', 'current'))
|
|
shutil.copytree(os.path.join(self.repository_directory, 'metadata'),
|
|
os.path.join(self.client_directory, self.repository_name, 'metadata',
|
|
'current'))
|
|
|
|
# Set the url prefix required by the 'tuf/client/updater.py' updater.
|
|
# 'path/to/tmp/repository' -> 'localhost:8001/tmp/repository'.
|
|
repository_basepath = self.repository_directory[len(os.getcwd()):]
|
|
url_prefix = \
|
|
'http://localhost:' + str(self.SERVER_PORT) + repository_basepath
|
|
|
|
# Setting 'tuf.settings.repository_directory' with the temporary client
|
|
# directory copied from the original repository files.
|
|
tuf.settings.repositories_directory = self.client_directory
|
|
self.repository_mirrors = {'mirror1': {'url_prefix': url_prefix,
|
|
'metadata_path': 'metadata',
|
|
'targets_path': 'targets',
|
|
'confined_target_dirs': ['']}}
|
|
|
|
# Create the repository instance. The test cases will use this client
|
|
# updater to refresh metadata, fetch target files, etc.
|
|
self.repository_updater = updater.Updater(self.repository_name,
|
|
self.repository_mirrors)
|
|
|
|
|
|
|
|
def tearDown(self):
|
|
# Modified_TestCase.tearDown() automatically deletes temporary files and
|
|
# directories that may have been created during each test case.
|
|
unittest_toolbox.Modified_TestCase.tearDown(self)
|
|
tuf.roledb.clear_roledb(clear_all=True)
|
|
tuf.keydb.clear_keydb(clear_all=True)
|
|
|
|
|
|
def test_with_tuf_mode_1(self):
|
|
# Simulate a slow retrieval attack.
|
|
# 'mode_1': When download begins,the server blocks the download for a long
|
|
# time by doing nothing before it sends the first byte of data.
|
|
|
|
server_process = self._start_slow_server('mode_1')
|
|
|
|
# Verify that the TUF client detects replayed metadata and refuses to
|
|
# continue the update process.
|
|
client_filepath = os.path.join(self.client_directory, 'file1.txt')
|
|
try:
|
|
file1_target = self.repository_updater.get_one_valid_targetinfo('file1.txt')
|
|
self.repository_updater.download_target(file1_target, self.client_directory)
|
|
|
|
# Verify that the specific 'tuf.exceptions.SlowRetrievalError' exception is raised by
|
|
# each mirror.
|
|
except tuf.exceptions.NoWorkingMirrorError as exception:
|
|
for mirror_url, mirror_error in six.iteritems(exception.mirror_errors):
|
|
url_prefix = self.repository_mirrors['mirror1']['url_prefix']
|
|
url_file = os.path.join(url_prefix, 'targets', 'file1.txt')
|
|
|
|
# Verify that 'file1.txt' is the culprit.
|
|
self.assertEqual(url_file.replace('\\', '/'), mirror_url)
|
|
self.assertTrue(isinstance(mirror_error, tuf.exceptions.SlowRetrievalError))
|
|
|
|
else:
|
|
self.fail('TUF did not prevent a slow retrieval attack.')
|
|
|
|
finally:
|
|
self._stop_slow_server(server_process)
|
|
|
|
|
|
|
|
# The following test fails as a result of a change to TUF's download code.
|
|
# Rather than constructing urllib2 requests, we now use the requests library.
|
|
# This solves an HTTPS proxy issue, but has for the moment deprived us of a
|
|
# way to prevent certain this kind of slow retrieval attack.
|
|
# See conversation in PR: https://github.com/theupdateframework/tuf/pull/781
|
|
# TODO: Update download code to resolve the slow retrieval vulnerability.
|
|
@unittest.expectedFailure
|
|
def test_with_tuf_mode_2(self):
|
|
# Simulate a slow retrieval attack.
|
|
# 'mode_2': During the download process, the server blocks the download
|
|
# by sending just several characters every few seconds.
|
|
|
|
server_process = self._start_slow_server('mode_2')
|
|
client_filepath = os.path.join(self.client_directory, 'file1.txt')
|
|
original_average_download_speed = tuf.settings.MIN_AVERAGE_DOWNLOAD_SPEED
|
|
tuf.settings.MIN_AVERAGE_DOWNLOAD_SPEED = 3
|
|
|
|
try:
|
|
file1_target = self.repository_updater.get_one_valid_targetinfo('file1.txt')
|
|
self.repository_updater.download_target(file1_target, self.client_directory)
|
|
|
|
# Verify that the specific 'tuf.exceptions.SlowRetrievalError' exception is
|
|
# raised by each mirror. 'file1.txt' should be large enough to trigger a
|
|
# slow retrieval attack, otherwise the expected exception may not be
|
|
# consistently raised.
|
|
except tuf.exceptions.NoWorkingMirrorError as exception:
|
|
for mirror_url, mirror_error in six.iteritems(exception.mirror_errors):
|
|
url_prefix = self.repository_mirrors['mirror1']['url_prefix']
|
|
url_file = os.path.join(url_prefix, 'targets', 'file1.txt')
|
|
|
|
# Verify that 'file1.txt' is the culprit.
|
|
self.assertEqual(url_file.replace('\\', '/'), mirror_url)
|
|
self.assertTrue(isinstance(mirror_error, tuf.exceptions.SlowRetrievalError))
|
|
|
|
else:
|
|
# Another possibility is to check for a successfully downloaded
|
|
# 'file1.txt' at this point.
|
|
self.fail('TUF did not prevent a slow retrieval attack.')
|
|
|
|
finally:
|
|
self._stop_slow_server(server_process)
|
|
tuf.settings.MIN_AVERAGE_DOWNLOAD_SPEED = original_average_download_speed
|
|
|
|
|
|
if __name__ == '__main__':
|
|
unittest.main()
|