Fix well-known lookups with the federation certificate whitelist (#5997)

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Amber Brown 2019-09-14 04:58:38 +10:00 committed by GitHub
parent c755955f33
commit 850dcfd2d3
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5 changed files with 63 additions and 15 deletions

1
changelog.d/5996.bugfix Normal file
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@ -0,0 +1 @@
federation_certificate_verification_whitelist now will not cause TypeErrors to be raised (a regression in 1.3). Additionally, it now supports internationalised domain names in their non-canonical representation.

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@ -110,8 +110,15 @@ class TlsConfig(Config):
# Support globs (*) in whitelist values
self.federation_certificate_verification_whitelist = []
for entry in fed_whitelist_entries:
try:
entry_regex = glob_to_regex(entry.encode("ascii").decode("ascii"))
except UnicodeEncodeError:
raise ConfigError(
"IDNA domain names are not allowed in the "
"federation_certificate_verification_whitelist: %s" % (entry,)
)
# Convert globs to regex
entry_regex = glob_to_regex(entry)
self.federation_certificate_verification_whitelist.append(entry_regex)
# List of custom certificate authorities for federation traffic validation

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@ -15,7 +15,6 @@
import logging
import idna
from service_identity import VerificationError
from service_identity.pyopenssl import verify_hostname, verify_ip_address
from zope.interface import implementer
@ -114,14 +113,20 @@ class ClientTLSOptionsFactory(object):
self._no_verify_ssl_context = self._no_verify_ssl.getContext()
self._no_verify_ssl_context.set_info_callback(self._context_info_cb)
def get_options(self, host):
def get_options(self, host: bytes):
# IPolicyForHTTPS.get_options takes bytes, but we want to compare
# against the str whitelist. The hostnames in the whitelist are already
# IDNA-encoded like the hosts will be here.
ascii_host = host.decode("ascii")
# Check if certificate verification has been enabled
should_verify = self._config.federation_verify_certificates
# Check if we've disabled certificate verification for this host
if should_verify:
for regex in self._config.federation_certificate_verification_whitelist:
if regex.match(host):
if regex.match(ascii_host):
should_verify = False
break
@ -162,7 +167,7 @@ class SSLClientConnectionCreator(object):
Replaces twisted.internet.ssl.ClientTLSOptions
"""
def __init__(self, hostname, ctx, verify_certs):
def __init__(self, hostname: bytes, ctx, verify_certs: bool):
self._ctx = ctx
self._verifier = ConnectionVerifier(hostname, verify_certs)
@ -190,21 +195,16 @@ class ConnectionVerifier(object):
# This code is based on twisted.internet.ssl.ClientTLSOptions.
def __init__(self, hostname, verify_certs):
def __init__(self, hostname: bytes, verify_certs):
self._verify_certs = verify_certs
if isIPAddress(hostname) or isIPv6Address(hostname):
self._hostnameBytes = hostname.encode("ascii")
_decoded = hostname.decode("ascii")
if isIPAddress(_decoded) or isIPv6Address(_decoded):
self._is_ip_address = True
else:
# twisted's ClientTLSOptions falls back to the stdlib impl here if
# idna is not installed, but points out that lacks support for
# IDNA2008 (http://bugs.python.org/issue17305).
#
# We can rely on having idna.
self._hostnameBytes = idna.encode(hostname)
self._is_ip_address = False
self._hostnameBytes = hostname
self._hostnameASCII = self._hostnameBytes.decode("ascii")
def verify_context_info_cb(self, ssl_connection, where):

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@ -217,7 +217,7 @@ class MatrixHostnameEndpoint(object):
self._tls_options = None
else:
self._tls_options = tls_client_options_factory.get_options(
self._parsed_uri.host.decode("ascii")
self._parsed_uri.host
)
self._srv_resolver = srv_resolver

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@ -16,6 +16,7 @@
import os
import idna
import yaml
from OpenSSL import SSL
@ -235,3 +236,42 @@ s4niecZKPBizL6aucT59CsunNmmb5Glq8rlAcU+1ZTZZzGYqVYhF6axB9Qg=
)
self.assertTrue(conf.acme_enabled)
def test_whitelist_idna_failure(self):
"""
The federation certificate whitelist will not allow IDNA domain names.
"""
config = {
"federation_certificate_verification_whitelist": [
"example.com",
"*.ドメイン.テスト",
]
}
t = TestConfig()
e = self.assertRaises(
ConfigError, t.read_config, config, config_dir_path="", data_dir_path=""
)
self.assertIn("IDNA domain names", str(e))
def test_whitelist_idna_result(self):
"""
The federation certificate whitelist will match on IDNA encoded names.
"""
config = {
"federation_certificate_verification_whitelist": [
"example.com",
"*.xn--eckwd4c7c.xn--zckzah",
]
}
t = TestConfig()
t.read_config(config, config_dir_path="", data_dir_path="")
cf = ClientTLSOptionsFactory(t)
# Not in the whitelist
opts = cf.get_options(b"notexample.com")
self.assertTrue(opts._verifier._verify_certs)
# Caught by the wildcard
opts = cf.get_options(idna.encode("テスト.ドメイン.テスト"))
self.assertFalse(opts._verifier._verify_certs)