diff options
Diffstat (limited to 'synapse/rest/register.py')
| -rw-r--r-- | synapse/rest/register.py | 61 |
1 files changed, 49 insertions, 12 deletions
diff --git a/synapse/rest/register.py b/synapse/rest/register.py index af528a44f6..804117ee09 100644 --- a/synapse/rest/register.py +++ b/synapse/rest/register.py @@ -21,6 +21,8 @@ from synapse.api.constants import LoginType from base import RestServlet, client_path_pattern import synapse.util.stringutils as stringutils +from hashlib import sha1 +import hmac import json import logging import urllib @@ -28,6 +30,16 @@ import urllib logger = logging.getLogger(__name__) +# We ought to be using hmac.compare_digest() but on older pythons it doesn't +# exist. It's a _really minor_ security flaw to use plain string comparison +# because the timing attack is so obscured by all the other code here it's +# unlikely to make much difference +if hasattr(hmac, "compare_digest"): + compare_digest = hmac.compare_digest +else: + compare_digest = lambda a, b: a == b + + class RegisterRestServlet(RestServlet): """Handles registration with the home server. @@ -142,6 +154,38 @@ class RegisterRestServlet(RestServlet): if not self.hs.config.enable_registration_captcha: raise SynapseError(400, "Captcha not required.") + yield self._check_recaptcha(request, register_json, session) + + session[LoginType.RECAPTCHA] = True # mark captcha as done + self._save_session(session) + defer.returnValue({ + "next": [LoginType.PASSWORD, LoginType.EMAIL_IDENTITY] + }) + + @defer.inlineCallbacks + def _check_recaptcha(self, request, register_json, session): + if ("captcha_bypass_hmac" in register_json and + self.hs.config.captcha_bypass_secret): + if "user" not in register_json: + raise SynapseError(400, "Captcha bypass needs 'user'") + + want = hmac.new( + key=self.hs.config.captcha_bypass_secret, + msg=register_json["user"], + digestmod=sha1, + ).hexdigest() + + # str() because otherwise hmac complains that 'unicode' does not + # have the buffer interface + got = str(register_json["captcha_bypass_hmac"]) + + if compare_digest(want, got): + session["user"] = register_json["user"] + defer.returnValue(None) + else: + raise SynapseError(400, "Captcha bypass HMAC incorrect", + errcode=Codes.CAPTCHA_NEEDED) + challenge = None user_response = None try: @@ -151,13 +195,7 @@ class RegisterRestServlet(RestServlet): raise SynapseError(400, "Captcha response is required", errcode=Codes.CAPTCHA_NEEDED) - # May be an X-Forwarding-For header depending on config - ip_addr = request.getClientIP() - if self.hs.config.captcha_ip_origin_is_x_forwarded: - # use the header - if request.requestHeaders.hasHeader("X-Forwarded-For"): - ip_addr = request.requestHeaders.getRawHeaders( - "X-Forwarded-For")[0] + ip_addr = self.hs.get_ip_from_request(request) handler = self.handlers.registration_handler yield handler.check_recaptcha( @@ -166,11 +204,6 @@ class RegisterRestServlet(RestServlet): challenge, user_response ) - session[LoginType.RECAPTCHA] = True # mark captcha as done - self._save_session(session) - defer.returnValue({ - "next": [LoginType.PASSWORD, LoginType.EMAIL_IDENTITY] - }) @defer.inlineCallbacks def _do_email_identity(self, request, register_json, session): @@ -195,6 +228,10 @@ class RegisterRestServlet(RestServlet): # captcha should've been done by this stage! raise SynapseError(400, "Captcha is required.") + if ("user" in session and "user" in register_json and + session["user"] != register_json["user"]): + raise SynapseError(400, "Cannot change user ID during registration") + password = register_json["password"].encode("utf-8") desired_user_id = (register_json["user"].encode("utf-8") if "user" in register_json else None) |