# # This file is licensed under the Affero General Public License (AGPL) version 3. # # Copyright (C) 2023 New Vector, Ltd # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU Affero General Public License as # published by the Free Software Foundation, either version 3 of the # License, or (at your option) any later version. # # See the GNU Affero General Public License for more details: # . # # Originally licensed under the Apache License, Version 2.0: # . # # [This file includes modifications made by New Vector Limited] # # import contextlib import logging import time from typing import TYPE_CHECKING, Any, Generator, Optional, Tuple, Union import attr from zope.interface import implementer from twisted.internet.address import UNIXAddress from twisted.internet.defer import Deferred from twisted.internet.interfaces import IAddress from twisted.python.failure import Failure from twisted.web.http import HTTPChannel from twisted.web.resource import IResource, Resource from twisted.web.server import Request from synapse.config.server import ListenerConfig from synapse.http import get_request_user_agent, redact_uri from synapse.http.proxy import ProxySite from synapse.http.request_metrics import RequestMetrics, requests_counter from synapse.logging.context import ( ContextRequest, LoggingContext, PreserveLoggingContext, ) from synapse.types import ISynapseReactor, Requester if TYPE_CHECKING: import opentracing from synapse.server import HomeServer logger = logging.getLogger(__name__) _next_request_seq = 0 class SynapseRequest(Request): """Class which encapsulates an HTTP request to synapse. All of the requests processed in synapse are of this type. It extends twisted's twisted.web.server.Request, and adds: * Unique request ID * A log context associated with the request * Redaction of access_token query-params in __repr__ * Logging at start and end * Metrics to record CPU, wallclock and DB time by endpoint. * A limit to the size of request which will be accepted It also provides a method `processing`, which returns a context manager. If this method is called, the request won't be logged until the context manager is closed; this is useful for asynchronous request handlers which may go on processing the request even after the client has disconnected. Attributes: logcontext: the log context for this request """ def __init__( self, channel: HTTPChannel, site: "SynapseSite", *args: Any, max_request_body_size: int = 1024, request_id_header: Optional[str] = None, **kw: Any, ): super().__init__(channel, *args, **kw) self._max_request_body_size = max_request_body_size self.request_id_header = request_id_header self.synapse_site = site self.reactor = site.reactor self._channel = channel # this is used by the tests self.start_time = 0.0 self.experimental_cors_msc3886 = site.experimental_cors_msc3886 # The requester, if authenticated. For federation requests this is the # server name, for client requests this is the Requester object. self._requester: Optional[Union[Requester, str]] = None # An opentracing span for this request. Will be closed when the request is # completely processed. self._opentracing_span: "Optional[opentracing.Span]" = None # we can't yet create the logcontext, as we don't know the method. self.logcontext: Optional[LoggingContext] = None # The `Deferred` to cancel if the client disconnects early and # `is_render_cancellable` is set. Expected to be set by `Resource.render`. self.render_deferred: Optional["Deferred[None]"] = None # A boolean indicating whether `render_deferred` should be cancelled if the # client disconnects early. Expected to be set by the coroutine started by # `Resource.render`, if rendering is asynchronous. self.is_render_cancellable: bool = False global _next_request_seq self.request_seq = _next_request_seq _next_request_seq += 1 # whether an asynchronous request handler has called processing() self._is_processing = False # the time when the asynchronous request handler completed its processing self._processing_finished_time: Optional[float] = None # what time we finished sending the response to the client (or the connection # dropped) self.finish_time: Optional[float] = None def __repr__(self) -> str: # We overwrite this so that we don't log ``access_token`` return "<%s at 0x%x method=%r uri=%r clientproto=%r site=%r>" % ( self.__class__.__name__, id(self), self.get_method(), self.get_redacted_uri(), self.clientproto.decode("ascii", errors="replace"), self.synapse_site.site_tag, ) def handleContentChunk(self, data: bytes) -> None: # we should have a `content` by now. assert self.content, "handleContentChunk() called before gotLength()" if self.content.tell() + len(data) > self._max_request_body_size: logger.warning( "Aborting connection from %s because the request exceeds maximum size: %s %s", self.client, self.get_method(), self.get_redacted_uri(), ) self.transport.abortConnection() return super().handleContentChunk(data) @property def requester(self) -> Optional[Union[Requester, str]]: return self._requester @requester.setter def requester(self, value: Union[Requester, str]) -> None: # Store the requester, and update some properties based on it. # This should only be called once. assert self._requester is None self._requester = value # A logging context should exist by now (and have a ContextRequest). assert self.logcontext is not None assert self.logcontext.request is not None ( requester, authenticated_entity, ) = self.get_authenticated_entity() self.logcontext.request.requester = requester # If there's no authenticated entity, it was the requester. self.logcontext.request.authenticated_entity = authenticated_entity or requester def set_opentracing_span(self, span: "opentracing.Span") -> None: """attach an opentracing span to this request Doing so will cause the span to be closed when we finish processing the request """ self._opentracing_span = span def get_request_id(self) -> str: request_id_value = None if self.request_id_header: request_id_value = self.getHeader(self.request_id_header) if request_id_value is None: request_id_value = str(self.request_seq) return "%s-%s" % (self.get_method(), request_id_value) def get_redacted_uri(self) -> str: """Gets the redacted URI associated with the request (or placeholder if the URI has not yet been received). Note: This is necessary as the placeholder value in twisted is str rather than bytes, so we need to sanitise `self.uri`. Returns: The redacted URI as a string. """ uri: Union[bytes, str] = self.uri if isinstance(uri, bytes): uri = uri.decode("ascii", errors="replace") return redact_uri(uri) def get_method(self) -> str: """Gets the method associated with the request (or placeholder if method has not yet been received). Note: This is necessary as the placeholder value in twisted is str rather than bytes, so we need to sanitise `self.method`. Returns: The request method as a string. """ method: Union[bytes, str] = self.method if isinstance(method, bytes): return self.method.decode("ascii") return method def get_authenticated_entity(self) -> Tuple[Optional[str], Optional[str]]: """ Get the "authenticated" entity of the request, which might be the user performing the action, or a user being puppeted by a server admin. Returns: A tuple: The first item is a string representing the user making the request. The second item is a string or None representing the user who authenticated when making this request. See Requester.authenticated_entity. """ # Convert the requester into a string that we can log if isinstance(self._requester, str): return self._requester, None elif isinstance(self._requester, Requester): requester = self._requester.user.to_string() authenticated_entity = self._requester.authenticated_entity # If this is a request where the target user doesn't match the user who # authenticated (e.g. and admin is puppetting a user) then we return both. if requester != authenticated_entity: return requester, authenticated_entity return requester, None elif self._requester is not None: # This shouldn't happen, but we log it so we don't lose information # and can see that we're doing something wrong. return repr(self._requester), None # type: ignore[unreachable] return None, None def render(self, resrc: Resource) -> None: # this is called once a Resource has been found to serve the request; in our # case the Resource in question will normally be a JsonResource. # create a LogContext for this request request_id = self.get_request_id() self.logcontext = LoggingContext( request_id, request=ContextRequest( request_id=request_id, ip_address=self.get_client_ip_if_available(), site_tag=self.synapse_site.site_tag, # The requester is going to be unknown at this point. requester=None, authenticated_entity=None, method=self.get_method(), url=self.get_redacted_uri(), protocol=self.clientproto.decode("ascii", errors="replace"), user_agent=get_request_user_agent(self), ), ) # override the Server header which is set by twisted self.setHeader("Server", self.synapse_site.server_version_string) with PreserveLoggingContext(self.logcontext): # we start the request metrics timer here with an initial stab # at the servlet name. For most requests that name will be # JsonResource (or a subclass), and JsonResource._async_render # will update it once it picks a servlet. servlet_name = resrc.__class__.__name__ self._started_processing(servlet_name) Request.render(self, resrc) # record the arrival of the request *after* # dispatching to the handler, so that the handler # can update the servlet name in the request # metrics requests_counter.labels(self.get_method(), self.request_metrics.name).inc() @contextlib.contextmanager def processing(self) -> Generator[None, None, None]: """Record the fact that we are processing this request. Returns a context manager; the correct way to use this is: async def handle_request(request): with request.processing("FooServlet"): await really_handle_the_request() Once the context manager is closed, the completion of the request will be logged, and the various metrics will be updated. """ if self._is_processing: raise RuntimeError("Request is already processing") self._is_processing = True try: yield except Exception: # this should already have been caught, and sent back to the client as a 500. logger.exception( "Asynchronous message handler raised an uncaught exception" ) finally: # the request handler has finished its work and either sent the whole response # back, or handed over responsibility to a Producer. self._processing_finished_time = time.time() self._is_processing = False if self._opentracing_span: self._opentracing_span.log_kv({"event": "finished processing"}) # if we've already sent the response, log it now; otherwise, we wait for the # response to be sent. if self.finish_time is not None: self._finished_processing() def finish(self) -> None: """Called when all response data has been written to this Request. Overrides twisted.web.server.Request.finish to record the finish time and do logging. """ self.finish_time = time.time() Request.finish(self) if self._opentracing_span: self._opentracing_span.log_kv({"event": "response sent"}) if not self._is_processing: assert self.logcontext is not None with PreserveLoggingContext(self.logcontext): self._finished_processing() def connectionLost(self, reason: Union[Failure, Exception]) -> None: """Called when the client connection is closed before the response is written. Overrides twisted.web.server.Request.connectionLost to record the finish time and do logging. """ # There is a bug in Twisted where reason is not wrapped in a Failure object # Detect this and wrap it manually as a workaround # More information: https://github.com/matrix-org/synapse/issues/7441 if not isinstance(reason, Failure): reason = Failure(reason) self.finish_time = time.time() Request.connectionLost(self, reason) if self.logcontext is None: logger.info( "Connection from %s lost before request headers were read", self.client ) return # we only get here if the connection to the client drops before we send # the response. # # It's useful to log it here so that we can get an idea of when # the client disconnects. with PreserveLoggingContext(self.logcontext): logger.info("Connection from client lost before response was sent") if self._opentracing_span: self._opentracing_span.log_kv( {"event": "client connection lost", "reason": str(reason.value)} ) if self._is_processing: if self.is_render_cancellable: if self.render_deferred is not None: # Throw a cancellation into the request processing, in the hope # that it will finish up sooner than it normally would. # The `self.processing()` context manager will call # `_finished_processing()` when done. with PreserveLoggingContext(): self.render_deferred.cancel() else: logger.error( "Connection from client lost, but have no Deferred to " "cancel even though the request is marked as cancellable." ) else: self._finished_processing() def _started_processing(self, servlet_name: str) -> None: """Record the fact that we are processing this request. This will log the request's arrival. Once the request completes, be sure to call finished_processing. Args: servlet_name: the name of the servlet which will be processing this request. This is used in the metrics. It is possible to update this afterwards by updating self.request_metrics.name. """ self.start_time = time.time() self.request_metrics = RequestMetrics() self.request_metrics.start( self.start_time, name=servlet_name, method=self.get_method() ) self.synapse_site.access_logger.debug( "%s - %s - Received request: %s %s", self.get_client_ip_if_available(), self.synapse_site.site_tag, self.get_method(), self.get_redacted_uri(), ) def _finished_processing(self) -> None: """Log the completion of this request and update the metrics""" assert self.logcontext is not None assert self.finish_time is not None usage = self.logcontext.get_resource_usage() if self._processing_finished_time is None: # we completed the request without anything calling processing() self._processing_finished_time = time.time() # the time between receiving the request and the request handler finishing processing_time = self._processing_finished_time - self.start_time # the time between the request handler finishing and the response being sent # to the client (nb may be negative) response_send_time = self.finish_time - self._processing_finished_time user_agent = get_request_user_agent(self, "-") # int(self.code) looks redundant, because self.code is already an int. # But self.code might be an HTTPStatus (which inherits from int)---which has # a different string representation. So ensure we really have an integer. code = str(int(self.code)) if not self.finished: # we didn't send the full response before we gave up (presumably because # the connection dropped) code += "!" log_level = logging.INFO if self._should_log_request() else logging.DEBUG # If this is a request where the target user doesn't match the user who # authenticated (e.g. and admin is puppetting a user) then we log both. requester, authenticated_entity = self.get_authenticated_entity() if authenticated_entity: requester = f"{authenticated_entity}|{requester}" self.synapse_site.access_logger.log( log_level, "%s - %s - {%s}" " Processed request: %.3fsec/%.3fsec (%.3fsec, %.3fsec) (%.3fsec/%.3fsec/%d)" ' %sB %s "%s %s %s" "%s" [%d dbevts]', self.get_client_ip_if_available(), self.synapse_site.site_tag, requester, processing_time, response_send_time, usage.ru_utime, usage.ru_stime, usage.db_sched_duration_sec, usage.db_txn_duration_sec, int(usage.db_txn_count), self.sentLength, code, self.get_method(), self.get_redacted_uri(), self.clientproto.decode("ascii", errors="replace"), user_agent, usage.evt_db_fetch_count, ) # complete the opentracing span, if any. if self._opentracing_span: self._opentracing_span.finish() try: self.request_metrics.stop(self.finish_time, self.code, self.sentLength) except Exception as e: logger.warning("Failed to stop metrics: %r", e) def _should_log_request(self) -> bool: """Whether we should log at INFO that we processed the request.""" if self.path == b"/health": return False if self.method == b"OPTIONS": return False return True def get_client_ip_if_available(self) -> str: """Logging helper. Return something useful when a client IP is not retrievable from a unix socket. In practice, this returns the socket file path on a SynapseRequest if using a unix socket and the normal IP address for TCP sockets. """ # getClientAddress().host returns a proper IP address for a TCP socket. But # unix sockets have no concept of IP addresses or ports and return a # UNIXAddress containing a 'None' value. In order to get something usable for # logs(where this is used) get the unix socket file. getHost() returns a # UNIXAddress containing a value of the socket file and has an instance # variable of 'name' encoded as a byte string containing the path we want. # Decode to utf-8 so it looks nice. if isinstance(self.getClientAddress(), UNIXAddress): return self.getHost().name.decode("utf-8") else: return self.getClientAddress().host def request_info(self) -> "RequestInfo": h = self.getHeader(b"User-Agent") user_agent = h.decode("ascii", "replace") if h else None return RequestInfo(user_agent=user_agent, ip=self.get_client_ip_if_available()) class XForwardedForRequest(SynapseRequest): """Request object which honours proxy headers Extends SynapseRequest to replace getClientIP, getClientAddress, and isSecure with information from request headers. """ # the client IP and ssl flag, as extracted from the headers. _forwarded_for: "Optional[_XForwardedForAddress]" = None _forwarded_https: bool = False def requestReceived(self, command: bytes, path: bytes, version: bytes) -> None: # this method is called by the Channel once the full request has been # received, to dispatch the request to a resource. # We can use it to set the IP address and protocol according to the # headers. self._process_forwarded_headers() return super().requestReceived(command, path, version) def _process_forwarded_headers(self) -> None: headers = self.requestHeaders.getRawHeaders(b"x-forwarded-for") if not headers: return # for now, we just use the first x-forwarded-for header. Really, we ought # to start from the client IP address, and check whether it is trusted; if it # is, work backwards through the headers until we find an untrusted address. # see https://github.com/matrix-org/synapse/issues/9471 self._forwarded_for = _XForwardedForAddress( headers[0].split(b",")[0].strip().decode("ascii") ) # if we got an x-forwarded-for header, also look for an x-forwarded-proto header header = self.getHeader(b"x-forwarded-proto") if header is not None: self._forwarded_https = header.lower() == b"https" else: # this is done largely for backwards-compatibility so that people that # haven't set an x-forwarded-proto header don't get a redirect loop. logger.warning( "forwarded request lacks an x-forwarded-proto header: assuming https" ) self._forwarded_https = True def isSecure(self) -> bool: if self._forwarded_https: return True return super().isSecure() def getClientIP(self) -> str: """ Return the IP address of the client who submitted this request. This method is deprecated. Use getClientAddress() instead. """ if self._forwarded_for is not None: return self._forwarded_for.host return super().getClientIP() def getClientAddress(self) -> IAddress: """ Return the address of the client who submitted this request. """ if self._forwarded_for is not None: return self._forwarded_for return super().getClientAddress() @implementer(IAddress) @attr.s(frozen=True, slots=True, auto_attribs=True) class _XForwardedForAddress: host: str class SynapseSite(ProxySite): """ Synapse-specific twisted http Site This does two main things. First, it replaces the requestFactory in use so that we build SynapseRequests instead of regular t.w.server.Requests. All of the constructor params are really just parameters for SynapseRequest. Second, it inhibits the log() method called by Request.finish, since SynapseRequest does its own logging. """ def __init__( self, logger_name: str, site_tag: str, config: ListenerConfig, resource: IResource, server_version_string: str, max_request_body_size: int, reactor: ISynapseReactor, hs: "HomeServer", ): """ Args: logger_name: The name of the logger to use for access logs. site_tag: A tag to use for this site - mostly in access logs. config: Configuration for the HTTP listener corresponding to this site resource: The base of the resource tree to be used for serving requests on this site server_version_string: A string to present for the Server header max_request_body_size: Maximum request body length to allow before dropping the connection reactor: reactor to be used to manage connection timeouts """ super().__init__( resource=resource, reactor=reactor, hs=hs, ) self.site_tag = site_tag self.reactor = reactor assert config.http_options is not None proxied = config.http_options.x_forwarded request_class = XForwardedForRequest if proxied else SynapseRequest request_id_header = config.http_options.request_id_header self.experimental_cors_msc3886: bool = ( config.http_options.experimental_cors_msc3886 ) def request_factory(channel: HTTPChannel, queued: bool) -> Request: return request_class( channel, self, max_request_body_size=max_request_body_size, queued=queued, request_id_header=request_id_header, ) self.requestFactory = request_factory # type: ignore self.access_logger = logging.getLogger(logger_name) self.server_version_string = server_version_string.encode("ascii") def log(self, request: SynapseRequest) -> None: pass @attr.s(auto_attribs=True, frozen=True, slots=True) class RequestInfo: user_agent: Optional[str] ip: str