From 850dcfd2d3a1d689042fb38c8a16b652244068c2 Mon Sep 17 00:00:00 2001 From: Amber Brown Date: Sat, 14 Sep 2019 04:58:38 +1000 Subject: Fix well-known lookups with the federation certificate whitelist (#5997) --- changelog.d/5996.bugfix | 1 + synapse/config/tls.py | 9 ++++- synapse/crypto/context_factory.py | 26 +++++++------- synapse/http/federation/matrix_federation_agent.py | 2 +- tests/config/test_tls.py | 40 ++++++++++++++++++++++ 5 files changed, 63 insertions(+), 15 deletions(-) create mode 100644 changelog.d/5996.bugfix diff --git a/changelog.d/5996.bugfix b/changelog.d/5996.bugfix new file mode 100644 index 0000000000..05e31faaa2 --- /dev/null +++ b/changelog.d/5996.bugfix @@ -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. diff --git a/synapse/config/tls.py b/synapse/config/tls.py index c0148aa95c..fc47ba3e9a 100644 --- a/synapse/config/tls.py +++ b/synapse/config/tls.py @@ -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 diff --git a/synapse/crypto/context_factory.py b/synapse/crypto/context_factory.py index 06e63a96b5..e93f0b3705 100644 --- a/synapse/crypto/context_factory.py +++ b/synapse/crypto/context_factory.py @@ -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): diff --git a/synapse/http/federation/matrix_federation_agent.py b/synapse/http/federation/matrix_federation_agent.py index feae7de5be..647d26dc56 100644 --- a/synapse/http/federation/matrix_federation_agent.py +++ b/synapse/http/federation/matrix_federation_agent.py @@ -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 diff --git a/tests/config/test_tls.py b/tests/config/test_tls.py index 8e0c4b9533..b02780772a 100644 --- a/tests/config/test_tls.py +++ b/tests/config/test_tls.py @@ -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) -- cgit 1.4.1