From ea26e9a98b0541fc886a1cb826a38352b7599dbe Mon Sep 17 00:00:00 2001 From: Patrick Cloke Date: Wed, 1 Jul 2020 09:10:23 -0400 Subject: Ensure that HTML pages served from Synapse include headers to avoid embedding. --- synapse/app/homeserver.py | 3 +- synapse/handlers/auth.py | 30 +++------- synapse/handlers/oidc_handler.py | 13 ++-- synapse/http/server.py | 76 +++++++++++++++++++++--- synapse/rest/client/v1/pusher.py | 10 +--- synapse/rest/client/v2_alpha/account.py | 16 +++-- synapse/rest/client/v2_alpha/account_validity.py | 11 +--- synapse/rest/client/v2_alpha/auth.py | 18 +----- synapse/rest/client/v2_alpha/register.py | 10 ++-- synapse/rest/consent/consent_resource.py | 10 +--- 10 files changed, 103 insertions(+), 94 deletions(-) diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py index 8454d74858..41994dc14b 100644 --- a/synapse/app/homeserver.py +++ b/synapse/app/homeserver.py @@ -56,6 +56,7 @@ from synapse.http.server import ( OptionsResource, RootOptionsRedirectResource, RootRedirect, + StaticResource, ) from synapse.http.site import SynapseSite from synapse.logging.context import LoggingContext @@ -228,7 +229,7 @@ class SynapseHomeServer(HomeServer): if name in ["static", "client"]: resources.update( { - STATIC_PREFIX: File( + STATIC_PREFIX: StaticResource( os.path.join(os.path.dirname(synapse.__file__), "static") ) } diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py index 119678e67b..bb3b43d5ae 100644 --- a/synapse/handlers/auth.py +++ b/synapse/handlers/auth.py @@ -38,7 +38,7 @@ from synapse.api.errors import ( from synapse.api.ratelimiting import Ratelimiter from synapse.handlers.ui_auth import INTERACTIVE_AUTH_CHECKERS from synapse.handlers.ui_auth.checkers import UserInteractiveAuthChecker -from synapse.http.server import finish_request +from synapse.http.server import finish_request, respond_with_html from synapse.http.site import SynapseRequest from synapse.logging.context import defer_to_thread from synapse.metrics.background_process_metrics import run_as_background_process @@ -1055,13 +1055,8 @@ class AuthHandler(BaseHandler): ) # Render the HTML and return. - html_bytes = self._sso_auth_success_template.encode("utf-8") - request.setResponseCode(200) - request.setHeader(b"Content-Type", b"text/html; charset=utf-8") - request.setHeader(b"Content-Length", b"%d" % (len(html_bytes),)) - - request.write(html_bytes) - finish_request(request) + html = self._sso_auth_success_template + respond_with_html(request, 200, html) async def complete_sso_login( self, @@ -1081,13 +1076,7 @@ class AuthHandler(BaseHandler): # flow. deactivated = await self.store.get_user_deactivated_status(registered_user_id) if deactivated: - html_bytes = self._sso_account_deactivated_template.encode("utf-8") - - request.setResponseCode(403) - request.setHeader(b"Content-Type", b"text/html; charset=utf-8") - request.setHeader(b"Content-Length", b"%d" % (len(html_bytes),)) - request.write(html_bytes) - finish_request(request) + respond_with_html(request, 403, self._sso_account_deactivated_template) return self._complete_sso_login(registered_user_id, request, client_redirect_url) @@ -1128,17 +1117,12 @@ class AuthHandler(BaseHandler): # URL we redirect users to. redirect_url_no_params = client_redirect_url.split("?")[0] - html_bytes = self._sso_redirect_confirm_template.render( + html = self._sso_redirect_confirm_template.render( display_url=redirect_url_no_params, redirect_url=redirect_url, server_name=self._server_name, - ).encode("utf-8") - - request.setResponseCode(200) - request.setHeader(b"Content-Type", b"text/html; charset=utf-8") - request.setHeader(b"Content-Length", b"%d" % (len(html_bytes),)) - request.write(html_bytes) - finish_request(request) + ) + respond_with_html(request, 200, html) @staticmethod def add_query_param_to_url(url: str, param_name: str, param: Any): diff --git a/synapse/handlers/oidc_handler.py b/synapse/handlers/oidc_handler.py index 9c08eb5399..87f0c5e197 100644 --- a/synapse/handlers/oidc_handler.py +++ b/synapse/handlers/oidc_handler.py @@ -35,7 +35,7 @@ from typing_extensions import TypedDict from twisted.web.client import readBody from synapse.config import ConfigError -from synapse.http.server import finish_request +from synapse.http.server import respond_with_html from synapse.http.site import SynapseRequest from synapse.logging.context import make_deferred_yieldable from synapse.push.mailer import load_jinja2_templates @@ -144,15 +144,10 @@ class OidcHandler: access_denied. error_description: A human-readable description of the error. """ - html_bytes = self._error_template.render( + html = self._error_template.render( error=error, error_description=error_description - ).encode("utf-8") - - request.setResponseCode(400) - request.setHeader(b"Content-Type", b"text/html; charset=utf-8") - request.setHeader(b"Content-Length", b"%i" % len(html_bytes)) - request.write(html_bytes) - finish_request(request) + ) + respond_with_html(request, 400, html) def _validate_metadata(self): """Verifies the provider metadata. diff --git a/synapse/http/server.py b/synapse/http/server.py index 2487a72171..2331a2a4b0 100644 --- a/synapse/http/server.py +++ b/synapse/http/server.py @@ -30,7 +30,7 @@ from twisted.internet import defer from twisted.python import failure from twisted.web import resource from twisted.web.server import NOT_DONE_YET, Request -from twisted.web.static import NoRangeStaticProducer +from twisted.web.static import File, NoRangeStaticProducer from twisted.web.util import redirectTo import synapse.events @@ -202,12 +202,7 @@ def return_html_error( else: body = error_template.render(code=code, msg=msg) - body_bytes = body.encode("utf-8") - request.setResponseCode(code) - request.setHeader(b"Content-Type", b"text/html; charset=utf-8") - request.setHeader(b"Content-Length", b"%i" % (len(body_bytes),)) - request.write(body_bytes) - finish_request(request) + respond_with_html(request, code, body) def wrap_async_request_handler(h): @@ -420,6 +415,18 @@ class DirectServeResource(resource.Resource): return NOT_DONE_YET +class StaticResource(File): + """ + A resource that represents a plain non-interpreted file or directory. + + Differs from the File resource by adding clickjacking protection. + """ + + def render_GET(self, request: Request): + set_clickjacking_protection_headers(request) + return super().render_GET(request) + + def _options_handler(request): """Request handler for OPTIONS requests @@ -530,7 +537,7 @@ def respond_with_json_bytes( code (int): The HTTP response code. json_bytes (bytes): The json bytes to use as the response body. send_cors (bool): Whether to send Cross-Origin Resource Sharing headers - http://www.w3.org/TR/cors/ + https://fetch.spec.whatwg.org/#http-cors-protocol Returns: twisted.web.server.NOT_DONE_YET""" @@ -568,6 +575,59 @@ def set_cors_headers(request): ) +def respond_with_html(request: Request, code: int, html: str): + """ + Wraps `respond_with_html_bytes` by first encoding HTML from a str to UTF-8 bytes. + """ + respond_with_html_bytes(request, code, html.encode("utf-8")) + + +def respond_with_html_bytes(request: Request, code: int, html_bytes: bytes): + """ + Sends HTML (encoded as UTF-8 bytes) as the response to the given request. + + Note that this adds clickjacking protection headers and finishes the request. + + Args: + request: The http request to respond to. + code: The HTTP response code. + html_bytes: The HTML bytes to use as the response body. + """ + # could alternatively use request.notifyFinish() and flip a flag when + # the Deferred fires, but since the flag is RIGHT THERE it seems like + # a waste. + if request._disconnected: + logger.warning( + "Not sending response to request %s, already disconnected.", request + ) + return + + request.setResponseCode(code) + request.setHeader(b"Content-Type", b"text/html; charset=utf-8") + request.setHeader(b"Content-Length", b"%d" % (len(html_bytes),)) + + # Ensure this content cannot be embedded. + set_clickjacking_protection_headers(request) + + request.write(html_bytes) + finish_request(request) + + +def set_clickjacking_protection_headers(request: Request): + """ + Set headers to guard against clickjacking of embedded content. + + This sets the X-Frame-Options and Content-Security-Policy headers which instructs + browsers to not allow the HTML of the response to be embedded onto another + page. + + Args: + request: The http request to add the headers to. + """ + request.setHeader(b"X-Frame-Options", b"DENY") + request.setHeader(b"Content-Security-Policy", b"frame-ancestors 'none';") + + def finish_request(request): """ Finish writing the response to the request. diff --git a/synapse/rest/client/v1/pusher.py b/synapse/rest/client/v1/pusher.py index 550a2f1b44..5f65cb7d83 100644 --- a/synapse/rest/client/v1/pusher.py +++ b/synapse/rest/client/v1/pusher.py @@ -16,7 +16,7 @@ import logging from synapse.api.errors import Codes, StoreError, SynapseError -from synapse.http.server import finish_request +from synapse.http.server import respond_with_html_bytes from synapse.http.servlet import ( RestServlet, assert_params_in_dict, @@ -177,13 +177,9 @@ class PushersRemoveRestServlet(RestServlet): self.notifier.on_new_replication_data() - request.setResponseCode(200) - request.setHeader(b"Content-Type", b"text/html; charset=utf-8") - request.setHeader( - b"Content-Length", b"%d" % (len(PushersRemoveRestServlet.SUCCESS_HTML),) + respond_with_html_bytes( + request, 200, PushersRemoveRestServlet.SUCCESS_HTML, ) - request.write(PushersRemoveRestServlet.SUCCESS_HTML) - finish_request(request) return None def on_OPTIONS(self, _): diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py index 1dc4a3247f..b58a77826f 100644 --- a/synapse/rest/client/v2_alpha/account.py +++ b/synapse/rest/client/v2_alpha/account.py @@ -21,7 +21,7 @@ from six.moves import http_client from synapse.api.constants import LoginType from synapse.api.errors import Codes, SynapseError, ThreepidValidationError from synapse.config.emailconfig import ThreepidBehaviour -from synapse.http.server import finish_request +from synapse.http.server import finish_request, respond_with_html from synapse.http.servlet import ( RestServlet, assert_params_in_dict, @@ -199,16 +199,15 @@ class PasswordResetSubmitTokenServlet(RestServlet): # Otherwise show the success template html = self.config.email_password_reset_template_success_html - request.setResponseCode(200) + status_code = 200 except ThreepidValidationError as e: - request.setResponseCode(e.code) + status_code = e.code # Show a failure page with a reason template_vars = {"failure_reason": e.msg} html = self.failure_email_template.render(**template_vars) - request.write(html.encode("utf-8")) - finish_request(request) + respond_with_html(request, status_code, html) class PasswordRestServlet(RestServlet): @@ -571,16 +570,15 @@ class AddThreepidEmailSubmitTokenServlet(RestServlet): # Otherwise show the success template html = self.config.email_add_threepid_template_success_html_content - request.setResponseCode(200) + status_code = 200 except ThreepidValidationError as e: - request.setResponseCode(e.code) + status_code = e.code # Show a failure page with a reason template_vars = {"failure_reason": e.msg} html = self.failure_email_template.render(**template_vars) - request.write(html.encode("utf-8")) - finish_request(request) + respond_with_html(request, status_code, html) class AddThreepidMsisdnSubmitTokenServlet(RestServlet): diff --git a/synapse/rest/client/v2_alpha/account_validity.py b/synapse/rest/client/v2_alpha/account_validity.py index 2f10fa64e2..d06336ceea 100644 --- a/synapse/rest/client/v2_alpha/account_validity.py +++ b/synapse/rest/client/v2_alpha/account_validity.py @@ -16,7 +16,7 @@ import logging from synapse.api.errors import AuthError, SynapseError -from synapse.http.server import finish_request +from synapse.http.server import respond_with_html from synapse.http.servlet import RestServlet from ._base import client_patterns @@ -26,9 +26,6 @@ logger = logging.getLogger(__name__) class AccountValidityRenewServlet(RestServlet): PATTERNS = client_patterns("/account_validity/renew$") - SUCCESS_HTML = ( - b"Your account has been successfully renewed." - ) def __init__(self, hs): """ @@ -59,11 +56,7 @@ class AccountValidityRenewServlet(RestServlet): status_code = 404 response = self.failure_html - request.setResponseCode(status_code) - request.setHeader(b"Content-Type", b"text/html; charset=utf-8") - request.setHeader(b"Content-Length", b"%d" % (len(response),)) - request.write(response.encode("utf8")) - finish_request(request) + respond_with_html(request, status_code, response) class AccountValiditySendMailServlet(RestServlet): diff --git a/synapse/rest/client/v2_alpha/auth.py b/synapse/rest/client/v2_alpha/auth.py index 75590ebaeb..8e585e9153 100644 --- a/synapse/rest/client/v2_alpha/auth.py +++ b/synapse/rest/client/v2_alpha/auth.py @@ -18,7 +18,7 @@ import logging from synapse.api.constants import LoginType from synapse.api.errors import SynapseError from synapse.api.urls import CLIENT_API_PREFIX -from synapse.http.server import finish_request +from synapse.http.server import respond_with_html from synapse.http.servlet import RestServlet, parse_string from ._base import client_patterns @@ -200,13 +200,7 @@ class AuthRestServlet(RestServlet): raise SynapseError(404, "Unknown auth stage type") # Render the HTML and return. - html_bytes = html.encode("utf8") - request.setResponseCode(200) - request.setHeader(b"Content-Type", b"text/html; charset=utf-8") - request.setHeader(b"Content-Length", b"%d" % (len(html_bytes),)) - - request.write(html_bytes) - finish_request(request) + respond_with_html(request, 200, html) return None async def on_POST(self, request, stagetype): @@ -263,13 +257,7 @@ class AuthRestServlet(RestServlet): raise SynapseError(404, "Unknown auth stage type") # Render the HTML and return. - html_bytes = html.encode("utf8") - request.setResponseCode(200) - request.setHeader(b"Content-Type", b"text/html; charset=utf-8") - request.setHeader(b"Content-Length", b"%d" % (len(html_bytes),)) - - request.write(html_bytes) - finish_request(request) + respond_with_html(request, 200, html) return None def on_OPTIONS(self, _): diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py index b9ffe86b2a..c8d2de7b54 100644 --- a/synapse/rest/client/v2_alpha/register.py +++ b/synapse/rest/client/v2_alpha/register.py @@ -38,7 +38,7 @@ from synapse.config.ratelimiting import FederationRateLimitConfig from synapse.config.registration import RegistrationConfig from synapse.config.server import is_threepid_reserved from synapse.handlers.auth import AuthHandler -from synapse.http.server import finish_request +from synapse.http.server import finish_request, respond_with_html from synapse.http.servlet import ( RestServlet, assert_params_in_dict, @@ -306,17 +306,15 @@ class RegistrationSubmitTokenServlet(RestServlet): # Otherwise show the success template html = self.config.email_registration_template_success_html_content - - request.setResponseCode(200) + status_code = 200 except ThreepidValidationError as e: - request.setResponseCode(e.code) + status_code = e.code # Show a failure page with a reason template_vars = {"failure_reason": e.msg} html = self.failure_email_template.render(**template_vars) - request.write(html.encode("utf-8")) - finish_request(request) + respond_with_html(request, status_code, html) class UsernameAvailabilityRestServlet(RestServlet): diff --git a/synapse/rest/consent/consent_resource.py b/synapse/rest/consent/consent_resource.py index 1ddf9997ff..4a20282d1b 100644 --- a/synapse/rest/consent/consent_resource.py +++ b/synapse/rest/consent/consent_resource.py @@ -29,7 +29,7 @@ from synapse.api.errors import NotFoundError, StoreError, SynapseError from synapse.config import ConfigError from synapse.http.server import ( DirectServeResource, - finish_request, + respond_with_html, wrap_html_request_handler, ) from synapse.http.servlet import parse_string @@ -197,12 +197,8 @@ class ConsentResource(DirectServeResource): template_html = self._jinja_env.get_template( path.join(TEMPLATE_LANGUAGE, template_name) ) - html_bytes = template_html.render(**template_args).encode("utf8") - - request.setHeader(b"Content-Type", b"text/html; charset=utf-8") - request.setHeader(b"Content-Length", b"%i" % len(html_bytes)) - request.write(html_bytes) - finish_request(request) + html = template_html.render(**template_args) + respond_with_html(request, 200, html) def _check_hash(self, userid, userhmac): """ -- cgit 1.4.1