Revert "Merge pull request #7315 from matrix-org/babolivier/request_token"

This reverts commit 6f4319368b3afab661c55367b9348f9b77bc04a5, reversing
changes made to 0d775fcc2d0c7b6a07dad5430256d4d6c75a9f0d.

7 files changed, 3 insertions, 121 deletions

diff --git a/changelog.d/7315.feature b/changelog.d/7315.feature
deleted file mode 100644
index ebcb4741b7..0000000000
--- a/changelog.d/7315.feature
+++ /dev/null
@@ -1 +0,0 @@
-Allow `/requestToken` endpoints to hide the existence (or lack thereof) of 3PID associations on the homeserver.
diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml
index abe03b2267..2ff0dd05a2 100644
--- a/docs/sample_config.yaml
+++ b/docs/sample_config.yaml
@@ -409,16 +409,6 @@ retention:
   #    longest_max_lifetime: 1y
   #    interval: 1d
 
-# Inhibits the /requestToken endpoints from returning an error that might leak
-# information about whether an e-mail address is in use or not on this
-# homeserver.
-# Note that for some endpoints the error situation is the e-mail already being
-# used, and for others the error is entering the e-mail being unused.
-# If this option is enabled, instead of returning an error, these endpoints will
-# act as if no error happened and return a fake session ID ('sid') to clients.
-#
-#request_token_inhibit_3pid_errors: true
-
 
 ## TLS ##
 
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 8acf3946eb..7525765fee 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -507,17 +507,6 @@ class ServerConfig(Config):
 
         self.enable_ephemeral_messages = config.get("enable_ephemeral_messages", False)
 
-        # Inhibits the /requestToken endpoints from returning an error that might leak
-        # information about whether an e-mail address is in use or not on this
-        # homeserver, and instead return a 200 with a fake sid if this kind of error is
-        # met, without sending anything.
-        # This is a compromise between sending an email, which could be a spam vector,
-        # and letting the client know which email address is bound to an account and
-        # which one isn't.
-        self.request_token_inhibit_3pid_errors = config.get(
-            "request_token_inhibit_3pid_errors", False,
-        )
-
     def has_tls_listener(self) -> bool:
         return any(l["tls"] for l in self.listeners)
 
@@ -978,16 +967,6 @@ class ServerConfig(Config):
           #  - shortest_max_lifetime: 3d
           #    longest_max_lifetime: 1y
           #    interval: 1d
-
-        # Inhibits the /requestToken endpoints from returning an error that might leak
-        # information about whether an e-mail address is in use or not on this
-        # homeserver.
-        # Note that for some endpoints the error situation is the e-mail already being
-        # used, and for others the error is entering the e-mail being unused.
-        # If this option is enabled, instead of returning an error, these endpoints will
-        # act as if no error happened and return a fake session ID ('sid') to clients.
-        #
-        #request_token_inhibit_3pid_errors: true
         """
             % locals()
         )
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index e2fdcda655..631cc74cb4 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -30,7 +30,7 @@ from synapse.http.servlet import (
 )
 from synapse.push.mailer import Mailer, load_jinja2_templates
 from synapse.util.msisdn import phone_number_to_msisdn
-from synapse.util.stringutils import assert_valid_client_secret, random_string
+from synapse.util.stringutils import assert_valid_client_secret
 from synapse.util.threepids import check_3pid_allowed
 
 from ._base import client_patterns, interactive_auth_handler
@@ -100,11 +100,6 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
         )
 
         if existing_user_id is None:
-            if self.config.request_token_inhibit_3pid_errors:
-                # Make the client think the operation succeeded. See the rationale in the
-                # comments for request_token_inhibit_3pid_errors.
-                return 200, {"sid": random_string(16)}
-
             raise SynapseError(400, "Email not found", Codes.THREEPID_NOT_FOUND)
 
         if self.config.threepid_behaviour_email == ThreepidBehaviour.REMOTE:
@@ -383,11 +378,6 @@ class EmailThreepidRequestTokenRestServlet(RestServlet):
         )
 
         if existing_user_id is not None:
-            if self.config.request_token_inhibit_3pid_errors:
-                # Make the client think the operation succeeded. See the rationale in the
-                # comments for request_token_inhibit_3pid_errors.
-                return 200, {"sid": random_string(16)}
-
             raise SynapseError(400, "Email is already in use", Codes.THREEPID_IN_USE)
 
         if self.config.threepid_behaviour_email == ThreepidBehaviour.REMOTE:
@@ -451,11 +441,6 @@ class MsisdnThreepidRequestTokenRestServlet(RestServlet):
         existing_user_id = await self.store.get_user_id_by_threepid("msisdn", msisdn)
 
         if existing_user_id is not None:
-            if self.hs.config.request_token_inhibit_3pid_errors:
-                # Make the client think the operation succeeded. See the rationale in the
-                # comments for request_token_inhibit_3pid_errors.
-                return 200, {"sid": random_string(16)}
-
             raise SynapseError(400, "MSISDN is already in use", Codes.THREEPID_IN_USE)
 
         if not self.hs.config.account_threepid_delegate_msisdn:
diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py
index 416489ae52..a09189b1b4 100644
--- a/synapse/rest/client/v2_alpha/register.py
+++ b/synapse/rest/client/v2_alpha/register.py
@@ -49,7 +49,7 @@ from synapse.http.servlet import (
 from synapse.push.mailer import load_jinja2_templates
 from synapse.util.msisdn import phone_number_to_msisdn
 from synapse.util.ratelimitutils import FederationRateLimiter
-from synapse.util.stringutils import assert_valid_client_secret, random_string
+from synapse.util.stringutils import assert_valid_client_secret
 from synapse.util.threepids import check_3pid_allowed
 
 from ._base import client_patterns, interactive_auth_handler
@@ -135,11 +135,6 @@ class EmailRegisterRequestTokenRestServlet(RestServlet):
         )
 
         if existing_user_id is not None:
-            if self.hs.config.request_token_inhibit_3pid_errors:
-                # Make the client think the operation succeeded. See the rationale in the
-                # comments for request_token_inhibit_3pid_errors.
-                return 200, {"sid": random_string(16)}
-
             raise SynapseError(400, "Email is already in use", Codes.THREEPID_IN_USE)
 
         if self.config.threepid_behaviour_email == ThreepidBehaviour.REMOTE:
@@ -207,11 +202,6 @@ class MsisdnRegisterRequestTokenRestServlet(RestServlet):
         )
 
         if existing_user_id is not None:
-            if self.hs.config.request_token_inhibit_3pid_errors:
-                # Make the client think the operation succeeded. See the rationale in the
-                # comments for request_token_inhibit_3pid_errors.
-                return 200, {"sid": random_string(16)}
-
             raise SynapseError(
                 400, "Phone number is already in use", Codes.THREEPID_IN_USE
             )
diff --git a/tests/rest/client/v2_alpha/test_account.py b/tests/rest/client/v2_alpha/test_account.py
index de72dc9a40..c3facc00eb 100644
--- a/tests/rest/client/v2_alpha/test_account.py
+++ b/tests/rest/client/v2_alpha/test_account.py
@@ -178,22 +178,6 @@ class PasswordResetTestCase(unittest.HomeserverTestCase):
         # Assert we can't log in with the new password
         self.attempt_wrong_password_login("kermit", new_password)
 
-    @unittest.override_config({"request_token_inhibit_3pid_errors": True})
-    def test_password_reset_bad_email_inhibit_error(self):
-        """Test that triggering a password reset with an email address that isn't bound
-        to an account doesn't leak the lack of binding for that address if configured
-        that way.
-        """
-        self.register_user("kermit", "monkey")
-        self.login("kermit", "monkey")
-
-        email = "test@example.com"
-
-        client_secret = "foobar"
-        session_id = self._request_token(email, client_secret)
-
-        self.assertIsNotNone(session_id)
-
     def _request_token(self, email, client_secret):
         request, channel = self.make_request(
             "POST",
diff --git a/tests/rest/client/v2_alpha/test_register.py b/tests/rest/client/v2_alpha/test_register.py
index 18527353f5..d0c997e385 100644
--- a/tests/rest/client/v2_alpha/test_register.py
+++ b/tests/rest/client/v2_alpha/test_register.py
@@ -33,11 +33,7 @@ from tests import unittest
 
 class RegisterRestServletTestCase(unittest.HomeserverTestCase):
 
-    servlets = [
-        login.register_servlets,
-        register.register_servlets,
-        synapse.rest.admin.register_servlets,
-    ]
+    servlets = [register.register_servlets]
     url = b"/_matrix/client/r0/register"
 
     def default_config(self, name="test"):
@@ -264,47 +260,6 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
             [["m.login.email.identity"]], (f["stages"] for f in flows)
         )
 
-    @unittest.override_config(
-        {
-            "request_token_inhibit_3pid_errors": True,
-            "public_baseurl": "https://test_server",
-            "email": {
-                "smtp_host": "mail_server",
-                "smtp_port": 2525,
-                "notif_from": "sender@host",
-            },
-        }
-    )
-    def test_request_token_existing_email_inhibit_error(self):
-        """Test that requesting a token via this endpoint doesn't leak existing
-        associations if configured that way.
-        """
-        user_id = self.register_user("kermit", "monkey")
-        self.login("kermit", "monkey")
-
-        email = "test@example.com"
-
-        # Add a threepid
-        self.get_success(
-            self.hs.get_datastore().user_add_threepid(
-                user_id=user_id,
-                medium="email",
-                address=email,
-                validated_at=0,
-                added_at=0,
-            )
-        )
-
-        request, channel = self.make_request(
-            "POST",
-            b"register/email/requestToken",
-            {"client_secret": "foobar", "email": email, "send_attempt": 1},
-        )
-        self.render(request)
-        self.assertEquals(200, channel.code, channel.result)
-
-        self.assertIsNotNone(channel.json_body.get("sid"))
-
 
 class AccountValidityTestCase(unittest.HomeserverTestCase):