forked-synapse/synapse/federation/transport/server/_base.py
Richard van der Hoff 60fa4935b5
Improve opentracing for incoming HTTP requests (#11618)
* remove `start_active_span_from_request`

Instead, pull out a separate function, `span_context_from_request`, to extract
the parent span, which we can then pass into `start_active_span` as
normal. This seems to be clearer all round.

* Remove redundant tags from `incoming-federation-request`

These are all wrapped up inside a parent span generated in AsyncResource, so
there's no point duplicating all the tags that are set there.

* Leave request spans open until the request completes

It may take some time for the response to be encoded into JSON, and that JSON
to be streamed back to the client, and really we want that inside the top-level
span, so let's hand responsibility for closure to the SynapseRequest.

* opentracing logs for HTTP request events

* changelog
2021-12-20 17:45:03 +00:00

328 lines
12 KiB
Python

# Copyright 2021 The Matrix.org Foundation C.I.C.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# 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 functools
import logging
import re
from typing import Any, Awaitable, Callable, Optional, Tuple, cast
from synapse.api.errors import Codes, FederationDeniedError, SynapseError
from synapse.api.urls import FEDERATION_V1_PREFIX
from synapse.http.server import HttpServer, ServletCallback
from synapse.http.servlet import parse_json_object_from_request
from synapse.http.site import SynapseRequest
from synapse.logging.context import run_in_background
from synapse.logging.opentracing import (
set_tag,
span_context_from_request,
start_active_span_follows_from,
whitelisted_homeserver,
)
from synapse.server import HomeServer
from synapse.types import JsonDict
from synapse.util.ratelimitutils import FederationRateLimiter
from synapse.util.stringutils import parse_and_validate_server_name
logger = logging.getLogger(__name__)
class AuthenticationError(SynapseError):
"""There was a problem authenticating the request"""
class NoAuthenticationError(AuthenticationError):
"""The request had no authentication information"""
class Authenticator:
def __init__(self, hs: HomeServer):
self._clock = hs.get_clock()
self.keyring = hs.get_keyring()
self.server_name = hs.hostname
self.store = hs.get_datastore()
self.federation_domain_whitelist = (
hs.config.federation.federation_domain_whitelist
)
self.notifier = hs.get_notifier()
self.replication_client = None
if hs.config.worker.worker_app:
self.replication_client = hs.get_tcp_replication()
# A method just so we can pass 'self' as the authenticator to the Servlets
async def authenticate_request(
self, request: SynapseRequest, content: Optional[JsonDict]
) -> str:
now = self._clock.time_msec()
json_request: JsonDict = {
"method": request.method.decode("ascii"),
"uri": request.uri.decode("ascii"),
"destination": self.server_name,
"signatures": {},
}
if content is not None:
json_request["content"] = content
origin = None
auth_headers = request.requestHeaders.getRawHeaders(b"Authorization")
if not auth_headers:
raise NoAuthenticationError(
401, "Missing Authorization headers", Codes.UNAUTHORIZED
)
for auth in auth_headers:
if auth.startswith(b"X-Matrix"):
(origin, key, sig) = _parse_auth_header(auth)
json_request["origin"] = origin
json_request["signatures"].setdefault(origin, {})[key] = sig
if (
self.federation_domain_whitelist is not None
and origin not in self.federation_domain_whitelist
):
raise FederationDeniedError(origin)
if origin is None or not json_request["signatures"]:
raise NoAuthenticationError(
401, "Missing Authorization headers", Codes.UNAUTHORIZED
)
await self.keyring.verify_json_for_server(
origin,
json_request,
now,
)
logger.debug("Request from %s", origin)
request.requester = origin
# If we get a valid signed request from the other side, its probably
# alive
retry_timings = await self.store.get_destination_retry_timings(origin)
if retry_timings and retry_timings.retry_last_ts:
run_in_background(self._reset_retry_timings, origin)
return origin
async def _reset_retry_timings(self, origin: str) -> None:
try:
logger.info("Marking origin %r as up", origin)
await self.store.set_destination_retry_timings(origin, None, 0, 0)
# Inform the relevant places that the remote server is back up.
self.notifier.notify_remote_server_up(origin)
if self.replication_client:
# If we're on a worker we try and inform master about this. The
# replication client doesn't hook into the notifier to avoid
# infinite loops where we send a `REMOTE_SERVER_UP` command to
# master, which then echoes it back to us which in turn pokes
# the notifier.
self.replication_client.send_remote_server_up(origin)
except Exception:
logger.exception("Error resetting retry timings on %s", origin)
def _parse_auth_header(header_bytes: bytes) -> Tuple[str, str, str]:
"""Parse an X-Matrix auth header
Args:
header_bytes: header value
Returns:
origin, key id, signature.
Raises:
AuthenticationError if the header could not be parsed
"""
try:
header_str = header_bytes.decode("utf-8")
params = header_str.split(" ")[1].split(",")
param_dict = {k: v for k, v in (kv.split("=", maxsplit=1) for kv in params)}
def strip_quotes(value: str) -> str:
if value.startswith('"'):
return value[1:-1]
else:
return value
origin = strip_quotes(param_dict["origin"])
# ensure that the origin is a valid server name
parse_and_validate_server_name(origin)
key = strip_quotes(param_dict["key"])
sig = strip_quotes(param_dict["sig"])
return origin, key, sig
except Exception as e:
logger.warning(
"Error parsing auth header '%s': %s",
header_bytes.decode("ascii", "replace"),
e,
)
raise AuthenticationError(
400, "Malformed Authorization header", Codes.UNAUTHORIZED
)
class BaseFederationServlet:
"""Abstract base class for federation servlet classes.
The servlet object should have a PATH attribute which takes the form of a regexp to
match against the request path (excluding the /federation/v1 prefix).
The servlet should also implement one or more of on_GET, on_POST, on_PUT, to match
the appropriate HTTP method. These methods must be *asynchronous* and have the
signature:
on_<METHOD>(self, origin, content, query, **kwargs)
With arguments:
origin (unicode|None): The authenticated server_name of the calling server,
unless REQUIRE_AUTH is set to False and authentication failed.
content (unicode|None): decoded json body of the request. None if the
request was a GET.
query (dict[bytes, list[bytes]]): Query params from the request. url-decoded
(ie, '+' and '%xx' are decoded) but note that it is *not* utf8-decoded
yet.
**kwargs (dict[unicode, unicode]): the dict mapping keys to path
components as specified in the path match regexp.
Returns:
Optional[Tuple[int, object]]: either (response code, response object) to
return a JSON response, or None if the request has already been handled.
Raises:
SynapseError: to return an error code
Exception: other exceptions will be caught, logged, and a 500 will be
returned.
"""
PATH = "" # Overridden in subclasses, the regex to match against the path.
REQUIRE_AUTH = True
PREFIX = FEDERATION_V1_PREFIX # Allows specifying the API version
RATELIMIT = True # Whether to rate limit requests or not
def __init__(
self,
hs: HomeServer,
authenticator: Authenticator,
ratelimiter: FederationRateLimiter,
server_name: str,
):
self.hs = hs
self.authenticator = authenticator
self.ratelimiter = ratelimiter
self.server_name = server_name
def _wrap(self, func: Callable[..., Awaitable[Tuple[int, Any]]]) -> ServletCallback:
authenticator = self.authenticator
ratelimiter = self.ratelimiter
@functools.wraps(func)
async def new_func(
request: SynapseRequest, *args: Any, **kwargs: str
) -> Optional[Tuple[int, Any]]:
"""A callback which can be passed to HttpServer.RegisterPaths
Args:
request:
*args: unused?
**kwargs: the dict mapping keys to path components as specified
in the path match regexp.
Returns:
(response code, response object) as returned by the callback method.
None if the request has already been handled.
"""
content = None
if request.method in [b"PUT", b"POST"]:
# TODO: Handle other method types? other content types?
content = parse_json_object_from_request(request)
try:
origin: Optional[str] = await authenticator.authenticate_request(
request, content
)
except NoAuthenticationError:
origin = None
if self.REQUIRE_AUTH:
logger.warning(
"authenticate_request failed: missing authentication"
)
raise
except Exception as e:
logger.warning("authenticate_request failed: %s", e)
raise
# update the active opentracing span with the authenticated entity
set_tag("authenticated_entity", origin)
# if the origin is authenticated and whitelisted, link to its span context
context = None
if origin and whitelisted_homeserver(origin):
context = span_context_from_request(request)
scope = start_active_span_follows_from(
"incoming-federation-request", contexts=(context,) if context else ()
)
with scope:
if origin and self.RATELIMIT:
with ratelimiter.ratelimit(origin) as d:
await d
if request._disconnected:
logger.warning(
"client disconnected before we started processing "
"request"
)
return None
response = await func(
origin, content, request.args, *args, **kwargs
)
else:
response = await func(
origin, content, request.args, *args, **kwargs
)
return response
return cast(ServletCallback, new_func)
def register(self, server: HttpServer) -> None:
pattern = re.compile("^" + self.PREFIX + self.PATH + "$")
for method in ("GET", "PUT", "POST"):
code = getattr(self, "on_%s" % (method), None)
if code is None:
continue
server.register_paths(
method,
(pattern,),
self._wrap(code),
self.__class__.__name__,
)