Gate peeking behind msc flags (#1731)

3 files changed, 33 insertions, 29 deletions

diff --git a/federationapi/federationapi.go b/federationapi/federationapi.go
index 350d5853..6188b283 100644
--- a/federationapi/federationapi.go
+++ b/federationapi/federationapi.go
@@ -38,10 +38,11 @@ func AddPublicRoutes(
 	federationSenderAPI federationSenderAPI.FederationSenderInternalAPI,
 	eduAPI eduserverAPI.EDUServerInputAPI,
 	keyAPI keyserverAPI.KeyInternalAPI,
+	mscCfg *config.MSCs,
 ) {
 	routing.Setup(
 		fedRouter, keyRouter, cfg, rsAPI,
 		eduAPI, federationSenderAPI, keyRing,
-		federation, userAPI, keyAPI,
+		federation, userAPI, keyAPI, mscCfg,
 	)
 }
diff --git a/federationapi/federationapi_test.go b/federationapi/federationapi_test.go
index aed47a36..923cd0ec 100644
--- a/federationapi/federationapi_test.go
+++ b/federationapi/federationapi_test.go
@@ -31,7 +31,7 @@ func TestRoomsV3URLEscapeDoNot404(t *testing.T) {
 	fsAPI := base.FederationSenderHTTPClient()
 	// TODO: This is pretty fragile, as if anything calls anything on these nils this test will break.
 	// Unfortunately, it makes little sense to instantiate these dependencies when we just want to test routing.
-	federationapi.AddPublicRoutes(base.PublicFederationAPIMux, base.PublicKeyAPIMux, &cfg.FederationAPI, nil, nil, keyRing, nil, fsAPI, nil, nil)
+	federationapi.AddPublicRoutes(base.PublicFederationAPIMux, base.PublicKeyAPIMux, &cfg.FederationAPI, nil, nil, keyRing, nil, fsAPI, nil, nil, &cfg.MSCs)
 	baseURL, cancel := test.ListenAndServe(t, base.PublicFederationAPIMux, true)
 	defer cancel()
 	serverName := gomatrixserverlib.ServerName(strings.TrimPrefix(baseURL, "https://"))
diff --git a/federationapi/routing/routing.go b/federationapi/routing/routing.go
index 7e76a143..b579ae1f 100644
--- a/federationapi/routing/routing.go
+++ b/federationapi/routing/routing.go
@@ -48,6 +48,7 @@ func Setup(
 	federation *gomatrixserverlib.FederationClient,
 	userAPI userapi.UserInternalAPI,
 	keyAPI keyserverAPI.KeyInternalAPI,
+	mscCfg *config.MSCs,
 ) {
 	v2keysmux := keyMux.PathPrefix("/v2").Subrouter()
 	v1fedmux := fedMux.PathPrefix("/v1").Subrouter()
@@ -229,35 +230,37 @@ func Setup(
 		},
 	)).Methods(http.MethodGet)
 
-	v1fedmux.Handle("/peek/{roomID}/{peekID}", httputil.MakeFedAPI(
-		"federation_peek", cfg.Matrix.ServerName, keys, wakeup,
-		func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
-			if roomserverAPI.IsServerBannedFromRoom(httpReq.Context(), rsAPI, vars["roomID"], request.Origin()) {
-				return util.JSONResponse{
-					Code: http.StatusForbidden,
-					JSON: jsonerror.Forbidden("Forbidden by server ACLs"),
+	if mscCfg.Enabled("msc2444") {
+		v1fedmux.Handle("/peek/{roomID}/{peekID}", httputil.MakeFedAPI(
+			"federation_peek", cfg.Matrix.ServerName, keys, wakeup,
+			func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
+				if roomserverAPI.IsServerBannedFromRoom(httpReq.Context(), rsAPI, vars["roomID"], request.Origin()) {
+					return util.JSONResponse{
+						Code: http.StatusForbidden,
+						JSON: jsonerror.Forbidden("Forbidden by server ACLs"),
+					}
 				}
-			}
-			roomID := vars["roomID"]
-			peekID := vars["peekID"]
-			queryVars := httpReq.URL.Query()
-			remoteVersions := []gomatrixserverlib.RoomVersion{}
-			if vers, ok := queryVars["ver"]; ok {
-				// The remote side supplied a ?ver= so use that to build up the list
-				// of supported room versions
-				for _, v := range vers {
-					remoteVersions = append(remoteVersions, gomatrixserverlib.RoomVersion(v))
+				roomID := vars["roomID"]
+				peekID := vars["peekID"]
+				queryVars := httpReq.URL.Query()
+				remoteVersions := []gomatrixserverlib.RoomVersion{}
+				if vers, ok := queryVars["ver"]; ok {
+					// The remote side supplied a ?ver= so use that to build up the list
+					// of supported room versions
+					for _, v := range vers {
+						remoteVersions = append(remoteVersions, gomatrixserverlib.RoomVersion(v))
+					}
+				} else {
+					// The remote side didn't supply a ?ver= so just assume that they only
+					// support room version 1
+					remoteVersions = append(remoteVersions, gomatrixserverlib.RoomVersionV1)
 				}
-			} else {
-				// The remote side didn't supply a ?ver= so just assume that they only
-				// support room version 1
-				remoteVersions = append(remoteVersions, gomatrixserverlib.RoomVersionV1)
-			}
-			return Peek(
-				httpReq, request, cfg, rsAPI, roomID, peekID, remoteVersions,
-			)
-		},
-	)).Methods(http.MethodPut, http.MethodDelete)
+				return Peek(
+					httpReq, request, cfg, rsAPI, roomID, peekID, remoteVersions,
+				)
+			},
+		)).Methods(http.MethodPut, http.MethodDelete)
+	}
 
 	v1fedmux.Handle("/make_join/{roomID}/{userID}", httputil.MakeFedAPI(
 		"federation_make_join", cfg.Matrix.ServerName, keys, wakeup,