From 546bc9e28b3d7758c732df8e120639d58d455164 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Wed, 4 Jul 2018 18:15:03 +0100 Subject: [PATCH] More server_name validation We need to do a bit more validation when we get a server name, but don't want to be re-doing it all over the shop, so factor out a separate parse_and_validate_server_name, and do the extra validation. Also, use it to verify the server name in the config file. --- changelog.d/3483.feature | 1 + synapse/config/server.py | 11 ++++-- synapse/federation/transport/server.py | 5 +-- synapse/http/endpoint.py | 47 +++++++++++++++++++++++--- tests/http/test_endpoint.py | 17 +++++++--- 5 files changed, 68 insertions(+), 13 deletions(-) create mode 100644 changelog.d/3483.feature diff --git a/changelog.d/3483.feature b/changelog.d/3483.feature new file mode 100644 index 000000000..afa2fbbcb --- /dev/null +++ b/changelog.d/3483.feature @@ -0,0 +1 @@ +Reject invalid server names in homeserver.yaml \ No newline at end of file diff --git a/synapse/config/server.py b/synapse/config/server.py index 968ecd9ea..71fd51e4b 100644 --- a/synapse/config/server.py +++ b/synapse/config/server.py @@ -16,6 +16,7 @@ import logging +from synapse.http.endpoint import parse_and_validate_server_name from ._base import Config, ConfigError logger = logging.Logger(__name__) @@ -25,6 +26,12 @@ class ServerConfig(Config): def read_config(self, config): self.server_name = config["server_name"] + + try: + parse_and_validate_server_name(self.server_name) + except ValueError as e: + raise ConfigError(str(e)) + self.pid_file = self.abspath(config.get("pid_file")) self.web_client = config["web_client"] self.web_client_location = config.get("web_client_location", None) @@ -162,8 +169,8 @@ class ServerConfig(Config): }) def default_config(self, server_name, **kwargs): - if ":" in server_name: - bind_port = int(server_name.split(":")[1]) + _, bind_port = parse_and_validate_server_name(server_name) + if bind_port is not None: unsecure_port = bind_port - 400 else: bind_port = 8448 diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py index 1180d4b69..e1fdcc89d 100644 --- a/synapse/federation/transport/server.py +++ b/synapse/federation/transport/server.py @@ -18,7 +18,7 @@ from twisted.internet import defer from synapse.api.urls import FEDERATION_PREFIX as PREFIX from synapse.api.errors import Codes, SynapseError, FederationDeniedError -from synapse.http.endpoint import parse_server_name +from synapse.http.endpoint import parse_and_validate_server_name from synapse.http.server import JsonResource from synapse.http.servlet import ( parse_json_object_from_request, parse_integer_from_args, parse_string_from_args, @@ -170,8 +170,9 @@ def _parse_auth_header(header_bytes): return value origin = strip_quotes(param_dict["origin"]) + # ensure that the origin is a valid server name - parse_server_name(origin) + parse_and_validate_server_name(origin) key = strip_quotes(param_dict["key"]) sig = strip_quotes(param_dict["sig"]) diff --git a/synapse/http/endpoint.py b/synapse/http/endpoint.py index 5a9cbb332..1b1123b29 100644 --- a/synapse/http/endpoint.py +++ b/synapse/http/endpoint.py @@ -12,6 +12,8 @@ # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. +import re + from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS from twisted.internet import defer from twisted.internet.error import ConnectError @@ -41,8 +43,6 @@ _Server = collections.namedtuple( def parse_server_name(server_name): """Split a server name into host/port parts. - Does some basic sanity checking of the - Args: server_name (str): server name to parse @@ -55,9 +55,6 @@ def parse_server_name(server_name): try: if server_name[-1] == ']': # ipv6 literal, hopefully - if server_name[0] != '[': - raise Exception() - return server_name, None domain_port = server_name.rsplit(":", 1) @@ -68,6 +65,46 @@ def parse_server_name(server_name): raise ValueError("Invalid server name '%s'" % server_name) +VALID_HOST_REGEX = re.compile( + "\\A[0-9a-zA-Z.-]+\\Z", +) + + +def parse_and_validate_server_name(server_name): + """Split a server name into host/port parts and do some basic validation. + + Args: + server_name (str): server name to parse + + Returns: + Tuple[str, int|None]: host/port parts. + + Raises: + ValueError if the server name could not be parsed. + """ + host, port = parse_server_name(server_name) + + # these tests don't need to be bulletproof as we'll find out soon enough + # if somebody is giving us invalid data. What we *do* need is to be sure + # that nobody is sneaking IP literals in that look like hostnames, etc. + + # look for ipv6 literals + if host[0] == '[': + if host[-1] != ']': + raise ValueError("Mismatched [...] in server name '%s'" % ( + server_name, + )) + return host, port + + # otherwise it should only be alphanumerics. + if not VALID_HOST_REGEX.match(host): + raise ValueError("Server name '%s' contains invalid characters" % ( + server_name, + )) + + return host, port + + def matrix_federation_endpoint(reactor, destination, ssl_context_factory=None, timeout=None): """Construct an endpoint for the given matrix destination. diff --git a/tests/http/test_endpoint.py b/tests/http/test_endpoint.py index cd74825c8..b8a48d20a 100644 --- a/tests/http/test_endpoint.py +++ b/tests/http/test_endpoint.py @@ -12,7 +12,10 @@ # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. -from synapse.http.endpoint import parse_server_name +from synapse.http.endpoint import ( + parse_server_name, + parse_and_validate_server_name, +) from tests import unittest @@ -30,17 +33,23 @@ class ServerNameTestCase(unittest.TestCase): for i, o in test_data.items(): self.assertEqual(parse_server_name(i), o) - def test_parse_bad_server_names(self): + def test_validate_bad_server_names(self): test_data = [ "", # empty "localhost:http", # non-numeric port "1234]", # smells like ipv6 literal but isn't + "[1234", + "underscore_.com", + "percent%65.com", + "1234:5678:80", # too many colons ] for i in test_data: try: - parse_server_name(i) + parse_and_validate_server_name(i) self.fail( - "Expected parse_server_name(\"%s\") to throw" % i, + "Expected parse_and_validate_server_name('%s') to throw" % ( + i, + ), ) except ValueError: pass