Merge pull request #5174 from matrix-org/dbkr/add_dummy_flow_to_recaptcha_only

Re-order registration stages to do msisdn & email auth last

1 files changed, 17 insertions, 5 deletions

diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py

index fa0cedb8d4..042f636135 100644
--- a/synapse/rest/client/v2_alpha/register.py
+++ b/synapse/rest/client/v2_alpha/register.py
@@ -348,18 +348,22 @@ class RegisterRestServlet(RestServlet):
         if self.hs.config.enable_registration_captcha:
             # only support 3PIDless registration if no 3PIDs are required
             if not require_email and not require_msisdn:
-                flows.extend([[LoginType.RECAPTCHA]])
+                # Also add a dummy flow here, otherwise if a client completes
+                # recaptcha first we'll assume they were going for this flow
+                # and complete the request, when they could have been trying to
+                # complete one of the flows with email/msisdn auth.
+                flows.extend([[LoginType.RECAPTCHA, LoginType.DUMMY]])
             # only support the email-only flow if we don't require MSISDN 3PIDs
             if not require_msisdn:
-                flows.extend([[LoginType.EMAIL_IDENTITY, LoginType.RECAPTCHA]])
+                flows.extend([[LoginType.RECAPTCHA, LoginType.EMAIL_IDENTITY]])
 
             if show_msisdn:
                 # only support the MSISDN-only flow if we don't require email 3PIDs
                 if not require_email:
-                    flows.extend([[LoginType.MSISDN, LoginType.RECAPTCHA]])
+                    flows.extend([[LoginType.RECAPTCHA, LoginType.MSISDN]])
                 # always let users provide both MSISDN & email
                 flows.extend([
-                    [LoginType.MSISDN, LoginType.EMAIL_IDENTITY, LoginType.RECAPTCHA],
+                    [LoginType.RECAPTCHA, LoginType.MSISDN, LoginType.EMAIL_IDENTITY],
                 ])
         else:
             # only support 3PIDless registration if no 3PIDs are required
@@ -382,7 +386,15 @@ class RegisterRestServlet(RestServlet):
         if self.hs.config.user_consent_at_registration:
             new_flows = []
             for flow in flows:
-                flow.append(LoginType.TERMS)
+                inserted = False
+                # m.login.terms should go near the end but before msisdn or email auth
+                for i, stage in enumerate(flow):
+                    if stage == LoginType.EMAIL_IDENTITY or stage == LoginType.MSISDN:
+                        flow.insert(i, LoginType.TERMS)
+                        inserted = True
+                        break
+                if not inserted:
+                    flow.append(LoginType.TERMS)
             flows.extend(new_flows)
 
         auth_result, params, session_id = yield self.auth_handler.check_auth(