[1/2] Allow homeservers to send registration emails | Sending the email

UPGRADE.rst

@@ -49,6 +49,55 @@ returned by the Client-Server API:
     # configured on port 443.
     curl -kv https://<host.name>/_matrix/client/versions 2>&1 | grep "Server:"
 
+Upgrading to v1.4.0
+===================
+
+Config options
+--------------
+
+**Note: Registration by email address or phone number will not work in this release unless
+some config options are changed from their defaults.**
+
+This is due to Synapse v1.4.0 now defaulting to sending registration and password reset tokens
+itself. This is for security reasons as well as putting less reliance on identity servers.
+However, currently Synapse only supports sending emails, and does not have support for
+phone-based password reset or account registration. If Synapse is configured to handle these on
+its own, phone-based password resets and registration will be disabled. For Synapse to send
+emails, the ``email`` block of the config must be filled out. If not, then password resets and
+registration via email will be disabled entirely.
+
+This release also deprecates the ``email.trust_identity_server_for_password_resets`` option
+and replaces it with ``account_threepid_delegate``. This option defines whether the homeserver
+should delegate an external server (typically an `identity server
+<https://matrix.org/docs/spec/identity_service/r0.2.1>`_) to handle sending password reset
+or registration messages via email or SMS.
+
+If ``email.trust_identity_server_for_password_resets`` was changed from its default to
+``true``, and ``account_threepid_delegate`` is not set to an identity server domain, then the
+server handling password resets and registration via third-party addresses will be set to the
+first entry in the Synapse config's ``trusted_third_party_id_servers`` entry. If no domains are
+configured, Synapse will throw an error on startup.
+
+If ``email.trust_identity_server_for_password_resets`` is not set to ``true`` and
+``account_threepid_delegate`` is not set to a domain, then Synapse will attempt to send
+password reset and registration messages itself.
+
+Email templates
+---------------
+
+If you have configured a custom template directory with the ``email.template_dir`` option, be
+aware that there are new templates regarding registration. ``registration.html`` and
+``registration.txt`` have been added and contain the text that is sent to a client upon
+registering via email address.
+
+``registration_success.html`` and ``registration_failure.html`` are templates containing HTML
+that will be shown to the user when they click the link in their registration email (if a
+redirect URL is not configured), either showing them a success or failure page.
+
+Synapse will expect these files to exist inside the configured template directory. To view the
+default templates, see `synapse/res/templates
+<https://github.com/matrix-org/synapse/tree/master/synapse/res/templates>`_.
+
 Upgrading to v1.2.0
 ===================
 
@@ -132,6 +181,19 @@ server for password resets, set ``trust_identity_server_for_password_resets`` to
 See the `sample configuration file <docs/sample_config.yaml>`_
 for more details on these settings.
 
+New email templates
+---------------
+Some new templates have been added to the default template directory for the purpose of the
+homeserver sending its own password reset emails. If you have configured a custom
+``template_dir`` in your Synapse config, these files will need to be added.
+
+``password_reset.html`` and ``password_reset.txt`` are HTML and plain text templates
+respectively that contain the contents of what will be emailed to the user upon attempting to
+reset their password via email. ``password_reset_success.html`` and
+``password_reset_failure.html`` are HTML files that the content of which (assuming no redirect
+URL is set) will be shown to the user after they attempt to click the link in the email sent
+to them.
+
 Upgrading to v0.99.0
 ====================
 

changelog.d/5835.feature

@@ -0,0 +1 @@
+Add the ability to send registration emails from the homeserver rather than delegating to an identity server.

docs/sample_config.yaml

@@ -1217,11 +1217,22 @@ password_config:
 #   #password_reset_template_html: password_reset.html
 #   #password_reset_template_text: password_reset.txt
 #
+#   # Templates for registration emails sent by the homeserver
+#   #
+#   #registration_template_html: registration.html
+#   #registration_template_text: registration.txt
+#
 #   # Templates for password reset success and failure pages that a user
 #   # will see after attempting to reset their password
 #   #
 #   #password_reset_template_success_html: password_reset_success.html
 #   #password_reset_template_failure_html: password_reset_failure.html
+#
+#   # Templates for registration success and failure pages that a user
+#   # will see after attempting to register using an email or phone
+#   #
+#   #registration_template_success_html: registration_success.html
+#   #registration_template_failure_html: registration_failure.html
 
 
 #password_providers:

synapse/config/emailconfig.py

@@ -75,7 +75,7 @@ def read_config(self, config, **kwargs):
             "renew_at"
         )
 
-        self.email_threepid_behaviour = (
+        self.threepid_behaviour = (
             # Have Synapse handle the email sending if account_threepid_delegate
             # is not defined
             ThreepidBehaviour.REMOTE
@@ -87,9 +87,14 @@ def read_config(self, config, **kwargs):
         # if they have this set and tell them to use the updated option, while using a default
         # identity server in the process.
         self.using_identity_server_from_trusted_list = False
-        if config.get("trust_identity_server_for_password_resets", False) is True:
+        if (
+            not self.account_threepid_delegate
+            and config.get("trust_identity_server_for_password_resets", False) is True
+        ):
             # Use the first entry in self.trusted_third_party_id_servers instead
             if self.trusted_third_party_id_servers:
+                # XXX: It's a little confusing that account_threepid_delegate is modifed
+                # both in RegistrationConfig and here. We should factor this bit out
                 self.account_threepid_delegate = self.trusted_third_party_id_servers[0]
                 self.using_identity_server_from_trusted_list = True
             else:
@@ -98,16 +103,13 @@ def read_config(self, config, **kwargs):
                     '"trusted_third_party_id_servers" but it is empty.'
                 )
 
-        self.local_threepid_emails_disabled_due_to_config = False
-        if (
-            self.email_threepid_behaviour == ThreepidBehaviour.LOCAL
-            and email_config == {}
-        ):
+        self.local_threepid_handling_disabled_due_to_email_config = False
+        if self.threepid_behaviour == ThreepidBehaviour.LOCAL and email_config == {}:
             # We cannot warn the user this has happened here
             # Instead do so when a user attempts to reset their password
-            self.local_threepid_emails_disabled_due_to_config = True
+            self.local_threepid_handling_disabled_due_to_email_config = True
 
-            self.email_threepid_behaviour = ThreepidBehaviour.OFF
+            self.threepid_behaviour = ThreepidBehaviour.OFF
 
         # Get lifetime of a validation token in milliseconds
         self.email_validation_token_lifetime = self.parse_duration(
@@ -117,7 +119,7 @@ def read_config(self, config, **kwargs):
         if (
             self.email_enable_notifs
             or account_validity_renewal_enabled
-            or self.email_threepid_behaviour == ThreepidBehaviour.LOCAL
+            or self.threepid_behaviour == ThreepidBehaviour.LOCAL
         ):
             # make sure we can import the required deps
             import jinja2
@@ -127,7 +129,7 @@ def read_config(self, config, **kwargs):
             jinja2
             bleach
 
-        if self.email_threepid_behaviour == ThreepidBehaviour.LOCAL:
+        if self.threepid_behaviour == ThreepidBehaviour.LOCAL:
             required = ["smtp_host", "smtp_port", "notif_from"]
 
             missing = []
@@ -146,28 +148,45 @@ def read_config(self, config, **kwargs):
                     % (", ".join(missing),)
                 )
 
-            # Templates for password reset emails
+            # These email templates have placeholders in them, and thus must be
+            # parsed using a templating engine during a request
             self.email_password_reset_template_html = email_config.get(
                 "password_reset_template_html", "password_reset.html"
             )
             self.email_password_reset_template_text = email_config.get(
                 "password_reset_template_text", "password_reset.txt"
             )
+            self.email_registration_template_html = email_config.get(
+                "registration_template_html", "registration.html"
+            )
+            self.email_registration_template_text = email_config.get(
+                "registration_template_text", "registration.txt"
+            )
             self.email_password_reset_template_failure_html = email_config.get(
                 "password_reset_template_failure_html", "password_reset_failure.html"
             )
-            # This template does not support any replaceable variables, so we will
-            # read it from the disk once during setup
+            self.email_registration_template_failure_html = email_config.get(
+                "registration_template_failure_html", "registration_failure.html"
+            )
+
+            # These templates do not support any placeholder variables, so we
+            # will read them from disk once during setup
             email_password_reset_template_success_html = email_config.get(
                 "password_reset_template_success_html", "password_reset_success.html"
             )
+            email_registration_template_success_html = email_config.get(
+                "registration_template_success_html", "registration_success.html"
+            )
 
             # Check templates exist
             for f in [
                 self.email_password_reset_template_html,
                 self.email_password_reset_template_text,
+                self.email_registration_template_html,
+                self.email_registration_template_text,
                 self.email_password_reset_template_failure_html,
                 email_password_reset_template_success_html,
+                email_registration_template_success_html,
             ]:
                 p = os.path.join(self.email_template_dir, f)
                 if not os.path.isfile(p):
@@ -177,9 +196,15 @@ def read_config(self, config, **kwargs):
             filepath = os.path.join(
                 self.email_template_dir, email_password_reset_template_success_html
             )
-            self.email_password_reset_template_success_html_content = self.read_file(
+            self.email_password_reset_template_success_html = self.read_file(
                 filepath, "email.password_reset_template_success_html"
             )
+            filepath = os.path.join(
+                self.email_template_dir, email_registration_template_success_html
+            )
+            self.email_registration_template_success_html_content = self.read_file(
+                filepath, "email.registration_template_success_html"
+            )
 
         if self.email_enable_notifs:
             required = [
@@ -291,11 +316,22 @@ def generate_config_section(self, config_dir_path, server_name, **kwargs):
         #   #password_reset_template_html: password_reset.html
         #   #password_reset_template_text: password_reset.txt
         #
+        #   # Templates for registration emails sent by the homeserver
+        #   #
+        #   #registration_template_html: registration.html
+        #   #registration_template_text: registration.txt
+        #
         #   # Templates for password reset success and failure pages that a user
         #   # will see after attempting to reset their password
         #   #
         #   #password_reset_template_success_html: password_reset_success.html
         #   #password_reset_template_failure_html: password_reset_failure.html
+        #
+        #   # Templates for registration success and failure pages that a user
+        #   # will see after attempting to register using an email or phone
+        #   #
+        #   #registration_template_success_html: registration_success.html
+        #   #registration_template_failure_html: registration_failure.html
         """
 
 

synapse/handlers/auth.py

@@ -461,10 +461,10 @@ def _check_threepid(self, medium, authdict, password_servlet=False, **kwargs):
         logger.info("Getting validated threepid. threepidcreds: %r", (threepid_creds,))
         if (
             not password_servlet
-            or self.hs.config.email_threepid_behaviour == ThreepidBehaviour.REMOTE
+            or self.hs.config.threepid_behaviour == ThreepidBehaviour.REMOTE
         ):
             threepid = yield identity_handler.threepid_from_creds(threepid_creds)
-        elif self.hs.config.email_threepid_behaviour == ThreepidBehaviour.LOCAL:
+        elif self.hs.config.threepid_behaviour == ThreepidBehaviour.LOCAL:
             row = yield self.store.get_threepid_validation_session(
                 medium,
                 threepid_creds["client_secret"],

synapse/handlers/identity.py

@@ -24,6 +24,7 @@
 from twisted.internet import defer
 
 from synapse.api.errors import CodeMessageException, HttpResponseException, SynapseError
+from synapse.util.stringutils import random_string
 
 from ._base import BaseHandler
 
@@ -196,6 +197,84 @@ def try_unbind_threepid_with_id_server(self, mxid, threepid, id_server):
 
         return changed
 
+    @defer.inlineCallbacks
+    def send_threepid_validation(
+        self,
+        email_address,
+        client_secret,
+        send_attempt,
+        send_email_func,
+        next_link=None,
+    ):
+        """Send a threepid validation email for password reset or
+        registration purposes
+
+        Args:
+            email_address (str): The user's email address
+            client_secret (str): The provided client secret
+            send_attempt (int): Which send attempt this is
+            send_email_func (func): A function that takes an email address, token,
+                                    client_secret and session_id, sends an email
+                                    and returns a Deferred.
+            next_link (str|None): The URL to redirect the user to after validation
+
+        Returns:
+            The new session_id upon success
+
+        Raises:
+            SynapseError is an error occurred when sending the email
+        """
+        # Check that this email/client_secret/send_attempt combo is new or
+        # greater than what we've seen previously
+        session = yield self.store.get_threepid_validation_session(
+            "email", client_secret, address=email_address, validated=False
+        )
+
+        # Check to see if a session already exists and that it is not yet
+        # marked as validated
+        if session and session.get("validated_at") is None:
+            session_id = session["session_id"]
+            last_send_attempt = session["last_send_attempt"]
+
+            # Check that the send_attempt is higher than previous attempts
+            if send_attempt <= last_send_attempt:
+                # If not, just return a success without sending an email
+                return session_id
+        else:
+            # An non-validated session does not exist yet.
+            # Generate a session id
+            session_id = random_string(16)
+
+        # Generate a new validation token
+        token = random_string(32)
+
+        # Send the mail with the link containing the token, client_secret
+        # and session_id
+        try:
+            yield send_email_func(email_address, token, client_secret, session_id)
+        except Exception:
+            logger.exception(
+                "Error sending threepid validation email to %s", email_address
+            )
+            raise SynapseError(500, "An error was encountered when sending the email")
+
+        token_expires = (
+            self.hs.clock.time_msec() + self.hs.config.email_validation_token_lifetime
+        )
+
+        yield self.store.start_or_continue_validation_session(
+            "email",
+            email_address,
+            session_id,
+            client_secret,
+            send_attempt,
+            next_link,
+            token,
+            token_expires,
+        )
+
+        return session_id
+
     @defer.inlineCallbacks
     def requestEmailToken(
         self, id_server, email, client_secret, send_attempt, next_link=None

synapse/handlers/register.py

@@ -414,18 +414,6 @@ def register_email(self, threepidCreds):
             if not check_3pid_allowed(self.hs, threepid["medium"], threepid["address"]):
                 raise RegistrationError(403, "Third party identifier is not allowed")
 
-    @defer.inlineCallbacks
-    def bind_emails(self, user_id, threepidCreds):
-        """Links emails with a user ID and informs an identity server.
-
-        Used only by c/s api v1
-        """
-
-        # Now we have a matrix ID, bind it to the threepids we were given
-        for c in threepidCreds:
-            # XXX: This should be a deferred list, shouldn't it?
-            yield self.identity_handler.bind_threepid(c, user_id)
-
     def check_user_id_not_appservice_exclusive(self, user_id, allowed_appservice=None):
         # don't allow people to register the server notices mxid
         if self._server_notices_mxid is not None: