226 lines
7.8 KiB
Python
226 lines
7.8 KiB
Python
# -*- coding: utf-8 -*-
|
|
# Copyright 2018 New Vector Ltd
|
|
#
|
|
# 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 hmac
|
|
import logging
|
|
from hashlib import sha256
|
|
from http import HTTPStatus
|
|
from os import path
|
|
|
|
import jinja2
|
|
from jinja2 import TemplateNotFound
|
|
|
|
from twisted.internet import defer
|
|
|
|
from synapse.api.errors import NotFoundError, StoreError, SynapseError
|
|
from synapse.config import ConfigError
|
|
from synapse.http.server import (
|
|
DirectServeResource,
|
|
finish_request,
|
|
wrap_html_request_handler,
|
|
)
|
|
from synapse.http.servlet import parse_string
|
|
from synapse.types import UserID
|
|
|
|
# language to use for the templates. TODO: figure this out from Accept-Language
|
|
TEMPLATE_LANGUAGE = "en"
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
# use hmac.compare_digest if we have it (python 2.7.7), else just use equality
|
|
if hasattr(hmac, "compare_digest"):
|
|
compare_digest = hmac.compare_digest
|
|
else:
|
|
|
|
def compare_digest(a, b):
|
|
return a == b
|
|
|
|
|
|
class ConsentResource(DirectServeResource):
|
|
"""A twisted Resource to display a privacy policy and gather consent to it
|
|
|
|
When accessed via GET, returns the privacy policy via a template.
|
|
|
|
When accessed via POST, records the user's consent in the database and
|
|
displays a success page.
|
|
|
|
The config should include a template_dir setting which contains templates
|
|
for the HTML. The directory should contain one subdirectory per language
|
|
(eg, 'en', 'fr'), and each language directory should contain the policy
|
|
document (named as '<version>.html') and a success page (success.html).
|
|
|
|
Both forms take a set of parameters from the browser. For the POST form,
|
|
these are normally sent as form parameters (but may be query-params); for
|
|
GET requests they must be query params. These are:
|
|
|
|
u: the complete mxid, or the localpart of the user giving their
|
|
consent. Required for both GET (where it is used as an input to the
|
|
template) and for POST (where it is used to find the row in the db
|
|
to update).
|
|
|
|
h: hmac_sha256(secret, u), where 'secret' is the privacy_secret in the
|
|
config file. If it doesn't match, the request is 403ed.
|
|
|
|
v: the version of the privacy policy being agreed to.
|
|
|
|
For GET: optional, and defaults to whatever was set in the config
|
|
file. Used to choose the version of the policy to pick from the
|
|
templates directory.
|
|
|
|
For POST: required; gives the value to be recorded in the database
|
|
against the user.
|
|
"""
|
|
|
|
def __init__(self, hs):
|
|
"""
|
|
Args:
|
|
hs (synapse.server.HomeServer): homeserver
|
|
"""
|
|
super().__init__()
|
|
|
|
self.hs = hs
|
|
self.store = hs.get_datastore()
|
|
self.registration_handler = hs.get_registration_handler()
|
|
|
|
# this is required by the request_handler wrapper
|
|
self.clock = hs.get_clock()
|
|
|
|
self._default_consent_version = hs.config.user_consent_version
|
|
if self._default_consent_version is None:
|
|
raise ConfigError(
|
|
"Consent resource is enabled but user_consent section is "
|
|
"missing in config file."
|
|
)
|
|
|
|
consent_template_directory = hs.config.user_consent_template_dir
|
|
|
|
loader = jinja2.FileSystemLoader(consent_template_directory)
|
|
self._jinja_env = jinja2.Environment(
|
|
loader=loader, autoescape=jinja2.select_autoescape(["html", "htm", "xml"])
|
|
)
|
|
|
|
if hs.config.form_secret is None:
|
|
raise ConfigError(
|
|
"Consent resource is enabled but form_secret is not set in "
|
|
"config file. It should be set to an arbitrary secret string."
|
|
)
|
|
|
|
self._hmac_secret = hs.config.form_secret.encode("utf-8")
|
|
|
|
@wrap_html_request_handler
|
|
async def _async_render_GET(self, request):
|
|
"""
|
|
Args:
|
|
request (twisted.web.http.Request):
|
|
"""
|
|
version = parse_string(request, "v", default=self._default_consent_version)
|
|
username = parse_string(request, "u", required=False, default="")
|
|
userhmac = None
|
|
has_consented = False
|
|
public_version = username == ""
|
|
if not public_version:
|
|
userhmac_bytes = parse_string(request, "h", required=True, encoding=None)
|
|
|
|
self._check_hash(username, userhmac_bytes)
|
|
|
|
if username.startswith("@"):
|
|
qualified_user_id = username
|
|
else:
|
|
qualified_user_id = UserID(username, self.hs.hostname).to_string()
|
|
|
|
u = await defer.maybeDeferred(self.store.get_user_by_id, qualified_user_id)
|
|
if u is None:
|
|
raise NotFoundError("Unknown user")
|
|
|
|
has_consented = u["consent_version"] == version
|
|
userhmac = userhmac_bytes.decode("ascii")
|
|
|
|
try:
|
|
self._render_template(
|
|
request,
|
|
"%s.html" % (version,),
|
|
user=username,
|
|
userhmac=userhmac,
|
|
version=version,
|
|
has_consented=has_consented,
|
|
public_version=public_version,
|
|
)
|
|
except TemplateNotFound:
|
|
raise NotFoundError("Unknown policy version")
|
|
|
|
@wrap_html_request_handler
|
|
async def _async_render_POST(self, request):
|
|
"""
|
|
Args:
|
|
request (twisted.web.http.Request):
|
|
"""
|
|
version = parse_string(request, "v", required=True)
|
|
username = parse_string(request, "u", required=True)
|
|
userhmac = parse_string(request, "h", required=True, encoding=None)
|
|
|
|
self._check_hash(username, userhmac)
|
|
|
|
if username.startswith("@"):
|
|
qualified_user_id = username
|
|
else:
|
|
qualified_user_id = UserID(username, self.hs.hostname).to_string()
|
|
|
|
try:
|
|
await self.store.user_set_consent_version(qualified_user_id, version)
|
|
except StoreError as e:
|
|
if e.code != 404:
|
|
raise
|
|
raise NotFoundError("Unknown user")
|
|
await self.registration_handler.post_consent_actions(qualified_user_id)
|
|
|
|
try:
|
|
self._render_template(request, "success.html")
|
|
except TemplateNotFound:
|
|
raise NotFoundError("success.html not found")
|
|
|
|
def _render_template(self, request, template_name, **template_args):
|
|
# get_template checks for ".." so we don't need to worry too much
|
|
# about path traversal here.
|
|
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)
|
|
|
|
def _check_hash(self, userid, userhmac):
|
|
"""
|
|
Args:
|
|
userid (unicode):
|
|
userhmac (bytes):
|
|
|
|
Raises:
|
|
SynapseError if the hash doesn't match
|
|
|
|
"""
|
|
want_mac = (
|
|
hmac.new(
|
|
key=self._hmac_secret, msg=userid.encode("utf-8"), digestmod=sha256
|
|
)
|
|
.hexdigest()
|
|
.encode("ascii")
|
|
)
|
|
|
|
if not compare_digest(want_mac, userhmac):
|
|
raise SynapseError(HTTPStatus.FORBIDDEN, "HMAC incorrect")
|