freeipa/ipatests/test_integration/test_http_kdc_proxy.py
Sergey Orlov 40a686ca84
ipatests: add test for kdcproxy handling reply split to several TCP packets
This is a regression test for the bug in python-kdcproxy mentioned in
https://github.com/latchset/kdcproxy/pull/44
  When the reply from AD is split into several TCP packets the kdc
  proxy software cannot handle it and returns a false error message
  indicating it cannot contact the KDC server.

This could be observed as login failures of AD user on IPA clients
when:
* IPA client was configured to use kdcproxy to communicate with AD
* kdcproxy used TCP to communicate with AD
* response from AD to kdcproxy was split into several packets

This patch also refactors and improves existing tests:
* switch to using pytest fixtures for test setup and cleanup steps to make
  them isolated and reusable
* simulate a much more restricted network environment: instead of blocking
  single 88 port we now block all outgoing traffic except few essential
  ports
* add basic tests for using kdcproxy to communicate between IPA client
  and AD DC.

Reviewed-By: Anuja More <amore@redhat.com>
2021-03-18 13:41:49 +01:00

260 lines
10 KiB
Python

#
# Copyright (C) 2016 FreeIPA Contributors see COPYING for license
#
from __future__ import absolute_import
import re
from contextlib import contextmanager
import pytest
from ipatests.pytest_ipa.integration import tasks
from ipatests.pytest_ipa.integration.firewall import Firewall
from ipatests.test_integration.base import IntegrationTest
from ipaplatform.paths import paths
class TestHttpKdcProxy(IntegrationTest):
topology = "line"
num_clients = 1
num_ad_domains = 1
@classmethod
def install(cls, mh):
super().install(mh)
cls.client = cls.clients[0]
cls.ad = cls.ads[0]
tasks.kinit_admin(cls.master)
cls.master.run_command(['ipa', 'pwpolicy-mod', '--minlife=0'])
tasks.install_adtrust(cls.master)
tasks.configure_dns_for_trust(cls.master, cls.ad)
tasks.establish_trust_with_ad(cls.master, cls.ad.domain.name)
@classmethod
def uninstall(cls, mh):
tasks.remove_trust_info_from_ad(
cls.master, cls.ad.domain.name, cls.ad.hostname)
super().uninstall(mh)
@pytest.fixture(autouse=True, scope='function')
def cleanup_credentials(self):
tasks.kdestroy_all(self.client)
tasks.clear_sssd_cache(self.client)
@pytest.fixture(scope='class')
def users(self, mh):
master = mh.master
ad = mh.ads[0]
users = {
'ipa': {
'name': 'ipa_test_user',
'password': 'SecretIpaTestUser',
'domain': mh.master.domain,
'test_service': 'HTTP/{}@{}'
.format(master.hostname, master.domain.realm),
},
'ad': {
'name': 'testuser@{}'.format(ad.domain.realm),
'password': 'Secret123',
'domain': ad.domain,
'test_service': 'HTTP/{}@{}'
.format(ad.hostname, ad.domain.realm),
}
}
tasks.kinit_admin(mh.master)
tasks.create_active_user(
mh.master, users['ipa']['name'], users['ipa']['password'])
yield users
tasks.kinit_admin(mh.master)
mh.master.run_command(['ipa', 'user-del', users['ipa']['name']])
@pytest.fixture()
def restrict_network_for_client(self, mh):
fw_rules_allow = [
['OUTPUT', '-p', 'udp', '--dport', '53', '-j', 'ACCEPT'],
['OUTPUT', '-p', 'tcp', '--dport', '80', '-j', 'ACCEPT'],
['OUTPUT', '-p', 'tcp', '--dport', '443', '-j', 'ACCEPT'],
['OUTPUT', '-p', 'tcp', '--sport', '22', '-j', 'ACCEPT']]
fw = Firewall(self.client)
fw.prepend_passthrough_rules(fw_rules_allow)
fw.passthrough_rule(['-P', 'OUTPUT', 'DROP'])
yield
fw.passthrough_rule(['-P', 'OUTPUT', 'ACCEPT'])
fw.remove_passthrough_rules(fw_rules_allow)
@pytest.fixture()
def client_use_kdcproxy(self, mh):
"""Configure client for using kdcproxy for IPA and AD domains."""
def replace_regexp_once(pattern, repl, string):
res, n = re.subn(pattern, repl, string)
assert n == 1
return res
krb5conf_backup = tasks.FileBackup(self.client, paths.KRB5_CONF)
krb5conf = self.client.get_file_contents(
paths.KRB5_CONF, encoding='utf-8')
kdc_url = 'https://{}/KdcProxy'.format(self.master.hostname)
# configure kdc proxy for IPA realm
krb5conf = replace_regexp_once(
r' kdc = .+', ' kdc = {}'.format(kdc_url), krb5conf)
krb5conf = replace_regexp_once(
r'kpasswd_server = .+', 'kpasswd_server = {}'.format(kdc_url),
krb5conf)
# configure kdc proxy for Windows AD realm
ad_realm_config = '''
{realm} = {{
kdc = {kdc_url}
kpasswd_server = {kdc_url}
}}
'''.format(realm=self.ad.domain.realm, kdc_url=kdc_url)
krb5conf = replace_regexp_once(
r'\[realms\]',
'[realms]' + ad_realm_config,
krb5conf
)
self.client.put_file_contents(paths.KRB5_CONF, krb5conf)
self.client.run_command(['systemctl', 'restart', 'sssd.service'])
yield
krb5conf_backup.restore()
self.client.run_command(['systemctl', 'restart', 'sssd.service'])
@contextmanager
def configure_kdc_proxy_for_ad_trust(self, use_tcp):
backup = tasks.FileBackup(self.master, paths.KDCPROXY_CONFIG)
with tasks.remote_ini_file(self.master, paths.KDCPROXY_CONFIG) as conf:
conf.set('global', 'use_dns', 'true')
conf.set('global', 'configs', 'mit')
if use_tcp:
conf.add_section(self.ad.domain.realm)
conf.set(self.ad.domain.realm, 'kerberos',
'kerberos+tcp://{}:88'.format(self.ad.hostname))
conf.set(self.ad.domain.realm, 'kpasswd',
'kpasswd+tcp://{}:464'.format(self.ad.hostname))
try:
self.master.run_command(['ipactl', 'restart'])
yield
finally:
backup.restore()
self.master.run_command(['ipactl', 'restart'])
def check_kerberos_requests(self, user, skip_kpasswd_check=False):
# KDC AS request
tasks.kinit_as_user(self.client, user['name'], user['password'])
# KDC TGS requests
self.client.run_command(['kvno', user['test_service']])
# KDC AS requests and kpasswd requests
# Changing password on Windows AD can not be done now because
# of default password policy mandating that minimal password lifetime
# is one day.
# Once we switch to dynamically creating test users in Windows AD
# and create an utility for modifying Group Policy Objects then
# we should update test setup and remove this condition.
def set_password(old_pass, new_pass):
with self.client.spawn_expect(['kpasswd', user['name']]) as e:
e.expect('Password for .+:')
e.sendline(old_pass)
e.expect_exact('Enter new password:')
e.sendline(new_pass)
e.expect_exact('Enter it again:')
e.sendline(new_pass)
e.expect_exit(ignore_remaining_output=True)
if not skip_kpasswd_check:
test_password = 'Secret123456'
set_password(user['password'], test_password)
# Restore password:
set_password(test_password, user['password'])
@pytest.mark.parametrize('user_origin', ['ipa', 'ad'])
def test_user_login_on_client_without_firewall(self, users, user_origin):
"""Basic check for test setup."""
self.check_kerberos_requests(users[user_origin],
skip_kpasswd_check=user_origin == 'ad')
@pytest.mark.usefixtures('restrict_network_for_client')
@pytest.mark.parametrize('user_origin', ['ipa', 'ad'])
def test_access_blocked_on_client_without_kdcproxy(
self, users, user_origin):
"""Check for test firewall setup."""
user = users[user_origin]
result = tasks.kinit_as_user(
self.client, user['name'], user['password'], raiseonerr=False)
expected_errors = [
("Cannot contact any KDC for realm '{}' while getting initial "
"credentials".format(user['domain'].realm)),
('Cannot find KDC for realm "{}" while getting initial '
"credentials".format(user['domain'].realm)),
]
assert (result.returncode == 1
and any(s in result.stderr_text for s in expected_errors))
@pytest.mark.usefixtures('restrict_network_for_client',
'client_use_kdcproxy')
def test_ipa_user_login_on_client_with_kdcproxy(self, users):
self.check_kerberos_requests(users['ipa'])
@pytest.mark.usefixtures('restrict_network_for_client',
'client_use_kdcproxy')
@pytest.mark.parametrize('use_tcp', [True, False])
def test_ad_user_login_on_client_with_kdcproxy(self, users, use_tcp):
with self.configure_kdc_proxy_for_ad_trust(use_tcp):
self.check_kerberos_requests(users['ad'], skip_kpasswd_check=True)
@pytest.fixture()
def windows_small_mtu_size(self, mh):
new_mtu = 70
def get_iface_name():
result = self.ad.run_command([
'powershell', '-c',
'(Get-NetIPAddress -IPAddress {}).InterfaceAlias'.format(
self.ad.ip)])
return result.stdout_text.strip()
def get_mtu(iface_name):
result = self.ad.run_command([
'netsh', 'interface', 'ipv4', 'show', 'subinterface',
iface_name])
mtu = result.stdout_text.strip().splitlines()[-1].split()[0]
return int(mtu)
def set_mtu(iface_name, mtu):
self.ad.run_command([
'netsh', 'interface', 'ipv4', 'set', 'subinterface',
iface_name, 'mtu={}'.format(mtu)])
iface_name = get_iface_name()
original_mtu = get_mtu(iface_name)
set_mtu(iface_name, new_mtu)
# `netsh` does not report failures with return code so we check
# it was successful by inspecting the actual value of MTU
assert get_mtu(iface_name) == new_mtu
yield
set_mtu(iface_name, original_mtu)
assert get_mtu(iface_name) == original_mtu
@pytest.mark.usefixtures('restrict_network_for_client',
'client_use_kdcproxy',
'windows_small_mtu_size')
def test_kdcproxy_handles_small_packets_from_ad(self, users):
"""Check that kdcproxy handles AD response split to several TCP packets
This is a regression test for the bug in python-kdcproxy:
https://github.com/latchset/kdcproxy/pull/44
When the reply from AD is split into several TCP packets the kdc
proxy software cannot handle it and returns a false error message
indicating it cannot contact the KDC server.
"""
with self.configure_kdc_proxy_for_ad_trust(use_tcp=True):
self.check_kerberos_requests(users['ad'], skip_kpasswd_check=True)