Implement /_synapse/admin/v1/register (#1911)

* Implement /_synapse/admin/v1/register

This is implemented identically to Synapse, so scripts which work
with Synapse should work with Dendrite.

```
    Test 27 POST /_synapse/admin/v1/register with shared secret... OK
    Test 28 POST /_synapse/admin/v1/register admin with shared secret... OK
    Test 29 POST /_synapse/admin/v1/register with shared secret downcases capitals... OK
    Test 30 POST /_synapse/admin/v1/register with shared secret disallows symbols... OK
```

Sytest however has `implementation_specific => "synapse"` which stops these
tests from running.

* Add missing muxes to gobind

* Linting

18 files changed, 220 insertions, 66 deletions

diff --git a/build/gobind-pinecone/monolith.go b/build/gobind-pinecone/monolith.go
index 09af80f6..e30057ed 100644
--- a/build/gobind-pinecone/monolith.go
+++ b/build/gobind-pinecone/monolith.go
@@ -334,6 +334,7 @@ func (m *DendriteMonolith) Start() {
 		base.PublicFederationAPIMux,
 		base.PublicKeyAPIMux,
 		base.PublicMediaAPIMux,
+		base.SynapseAdminMux,
 	)
 
 	httpRouter := mux.NewRouter().SkipClean(true).UseEncodedPath()
diff --git a/build/gobind-yggdrasil/monolith.go b/build/gobind-yggdrasil/monolith.go
index 5074f6da..33862804 100644
--- a/build/gobind-yggdrasil/monolith.go
+++ b/build/gobind-yggdrasil/monolith.go
@@ -173,6 +173,7 @@ func (m *DendriteMonolith) Start() {
 		base.PublicFederationAPIMux,
 		base.PublicKeyAPIMux,
 		base.PublicMediaAPIMux,
+		base.SynapseAdminMux,
 	)
 
 	httpRouter := mux.NewRouter()
diff --git a/clientapi/clientapi.go b/clientapi/clientapi.go
index 2c4fa5d6..562d89d2 100644
--- a/clientapi/clientapi.go
+++ b/clientapi/clientapi.go
@@ -35,6 +35,7 @@ import (
 // AddPublicRoutes sets up and registers HTTP handlers for the ClientAPI component.
 func AddPublicRoutes(
 	router *mux.Router,
+	synapseAdminRouter *mux.Router,
 	cfg *config.ClientAPI,
 	accountsDB accounts.Database,
 	federation *gomatrixserverlib.FederationClient,
@@ -56,7 +57,7 @@ func AddPublicRoutes(
 	}
 
 	routing.Setup(
-		router, cfg, eduInputAPI, rsAPI, asAPI,
+		router, synapseAdminRouter, cfg, eduInputAPI, rsAPI, asAPI,
 		accountsDB, userAPI, federation,
 		syncProducer, transactionsCache, fsAPI, keyAPI, extRoomsProvider, mscCfg,
 	)
diff --git a/clientapi/routing/register.go b/clientapi/routing/register.go
index 52641866..8823a41e 100644
--- a/clientapi/routing/register.go
+++ b/clientapi/routing/register.go
@@ -17,10 +17,7 @@ package routing
 
 import (
 	"context"
-	"crypto/hmac"
-	"crypto/sha1"
 	"encoding/json"
-	"errors"
 	"fmt"
 	"io/ioutil"
 	"net/http"
@@ -594,7 +591,6 @@ func handleRegistrationFlow(
 	accessToken string,
 	accessTokenErr error,
 ) util.JSONResponse {
-	// TODO: Shared secret registration (create new user scripts)
 	// TODO: Enable registration config flag
 	// TODO: Guest account upgrading
 
@@ -643,20 +639,6 @@ func handleRegistrationFlow(
 		// Add Recaptcha to the list of completed registration stages
 		AddCompletedSessionStage(sessionID, authtypes.LoginTypeRecaptcha)
 
-	case authtypes.LoginTypeSharedSecret:
-		// Check shared secret against config
-		valid, err := isValidMacLogin(cfg, r.Username, r.Password, r.Admin, r.Auth.Mac)
-
-		if err != nil {
-			util.GetLogger(req.Context()).WithError(err).Error("isValidMacLogin failed")
-			return jsonerror.InternalServerError()
-		} else if !valid {
-			return util.MessageResponse(http.StatusForbidden, "HMAC incorrect")
-		}
-
-		// Add SharedSecret to the list of completed registration stages
-		AddCompletedSessionStage(sessionID, authtypes.LoginTypeSharedSecret)
-
 	case authtypes.LoginTypeDummy:
 		// there is nothing to do
 		// Add Dummy to the list of completed registration stages
@@ -849,49 +831,6 @@ func completeRegistration(
 	}
 }
 
-// Used for shared secret registration.
-// Checks if the username, password and isAdmin flag matches the given mac.
-func isValidMacLogin(
-	cfg *config.ClientAPI,
-	username, password string,
-	isAdmin bool,
-	givenMac []byte,
-) (bool, error) {
-	sharedSecret := cfg.RegistrationSharedSecret
-
-	// Check that shared secret registration isn't disabled.
-	if cfg.RegistrationSharedSecret == "" {
-		return false, errors.New("Shared secret registration is disabled")
-	}
-
-	// Double check that username/password don't contain the HMAC delimiters. We should have
-	// already checked this.
-	if strings.Contains(username, "\x00") {
-		return false, errors.New("Username contains invalid character")
-	}
-	if strings.Contains(password, "\x00") {
-		return false, errors.New("Password contains invalid character")
-	}
-	if sharedSecret == "" {
-		return false, errors.New("Shared secret registration is disabled")
-	}
-
-	adminString := "notadmin"
-	if isAdmin {
-		adminString = "admin"
-	}
-	joined := strings.Join([]string{username, password, adminString}, "\x00")
-
-	mac := hmac.New(sha1.New, []byte(sharedSecret))
-	_, err := mac.Write([]byte(joined))
-	if err != nil {
-		return false, err
-	}
-	expectedMAC := mac.Sum(nil)
-
-	return hmac.Equal(givenMac, expectedMAC), nil
-}
-
 // checkFlows checks a single completed flow against another required one. If
 // one contains at least all of the stages that the other does, checkFlows
 // returns true.
@@ -995,3 +934,34 @@ func RegisterAvailable(
 		},
 	}
 }
+
+func handleSharedSecretRegistration(userAPI userapi.UserInternalAPI, sr *SharedSecretRegistration, req *http.Request) util.JSONResponse {
+	ssrr, err := NewSharedSecretRegistrationRequest(req.Body)
+	if err != nil {
+		return util.JSONResponse{
+			Code: 400,
+			JSON: jsonerror.BadJSON(fmt.Sprintf("malformed json: %s", err)),
+		}
+	}
+	valid, err := sr.IsValidMacLogin(ssrr.Nonce, ssrr.User, ssrr.Password, ssrr.Admin, ssrr.MacBytes)
+	if err != nil {
+		return util.ErrorResponse(err)
+	}
+	if !valid {
+		return util.JSONResponse{
+			Code: 403,
+			JSON: jsonerror.Forbidden("bad mac"),
+		}
+	}
+	// downcase capitals
+	ssrr.User = strings.ToLower(ssrr.User)
+
+	if resErr := validateUsername(ssrr.User); resErr != nil {
+		return *resErr
+	}
+	if resErr := validatePassword(ssrr.Password); resErr != nil {
+		return *resErr
+	}
+	deviceID := "shared_secret_registration"
+	return completeRegistration(req.Context(), userAPI, ssrr.User, ssrr.Password, "", req.RemoteAddr, req.UserAgent(), false, &ssrr.User, &deviceID)
+}
diff --git a/clientapi/routing/register_secret.go b/clientapi/routing/register_secret.go
new file mode 100644
index 00000000..f0436e32
--- /dev/null
+++ b/clientapi/routing/register_secret.go
@@ -0,0 +1,99 @@
+package routing
+
+import (
+	"context"
+	"crypto/hmac"
+	"crypto/sha1"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+	"time"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/util"
+	cache "github.com/patrickmn/go-cache"
+)
+
+type SharedSecretRegistrationRequest struct {
+	User     string `json:"username"`
+	Password string `json:"password"`
+	Nonce    string `json:"nonce"`
+	MacBytes []byte
+	MacStr   string `json:"mac"`
+	Admin    bool   `json:"admin"`
+}
+
+func NewSharedSecretRegistrationRequest(reader io.ReadCloser) (*SharedSecretRegistrationRequest, error) {
+	defer internal.CloseAndLogIfError(context.Background(), reader, "NewSharedSecretRegistrationRequest: failed to close request body")
+	var ssrr SharedSecretRegistrationRequest
+	err := json.NewDecoder(reader).Decode(&ssrr)
+	if err != nil {
+		return nil, err
+	}
+	ssrr.MacBytes, err = hex.DecodeString(ssrr.MacStr)
+	return &ssrr, err
+}
+
+type SharedSecretRegistration struct {
+	sharedSecret string
+	nonces       *cache.Cache
+}
+
+func NewSharedSecretRegistration(sharedSecret string) *SharedSecretRegistration {
+	return &SharedSecretRegistration{
+		sharedSecret: sharedSecret,
+		// nonces live for 5mins, purge every 10mins
+		nonces: cache.New(5*time.Minute, 10*time.Minute),
+	}
+}
+
+func (r *SharedSecretRegistration) GenerateNonce() string {
+	nonce := util.RandomString(16)
+	r.nonces.Set(nonce, true, cache.DefaultExpiration)
+	return nonce
+}
+
+func (r *SharedSecretRegistration) validNonce(nonce string) bool {
+	_, exists := r.nonces.Get(nonce)
+	return exists
+}
+
+func (r *SharedSecretRegistration) IsValidMacLogin(
+	nonce, username, password string,
+	isAdmin bool,
+	givenMac []byte,
+) (bool, error) {
+	// Check that shared secret registration isn't disabled.
+	if r.sharedSecret == "" {
+		return false, errors.New("Shared secret registration is disabled")
+	}
+	if !r.validNonce(nonce) {
+		return false, fmt.Errorf("Incorrect or expired nonce: %s", nonce)
+	}
+
+	// Check that username/password don't contain the HMAC delimiters.
+	if strings.Contains(username, "\x00") {
+		return false, errors.New("Username contains invalid character")
+	}
+	if strings.Contains(password, "\x00") {
+		return false, errors.New("Password contains invalid character")
+	}
+
+	adminString := "notadmin"
+	if isAdmin {
+		adminString = "admin"
+	}
+	joined := strings.Join([]string{nonce, username, password, adminString}, "\x00")
+
+	mac := hmac.New(sha1.New, []byte(r.sharedSecret))
+	_, err := mac.Write([]byte(joined))
+	if err != nil {
+		return false, err
+	}
+	expectedMAC := mac.Sum(nil)
+
+	return hmac.Equal(givenMac, expectedMAC), nil
+}
diff --git a/clientapi/routing/register_secret_test.go b/clientapi/routing/register_secret_test.go
new file mode 100644
index 00000000..e702b215
--- /dev/null
+++ b/clientapi/routing/register_secret_test.go
@@ -0,0 +1,43 @@
+package routing
+
+import (
+	"bytes"
+	"io/ioutil"
+	"testing"
+
+	"github.com/patrickmn/go-cache"
+)
+
+func TestSharedSecretRegister(t *testing.T) {
+	// these values have come from a local synapse instance to ensure compatibility
+	jsonStr := []byte(`{"admin":false,"mac":"f1ba8d37123866fd659b40de4bad9b0f8965c565","nonce":"759f047f312b99ff428b21d581256f8592b8976e58bc1b543972dc6147e529a79657605b52d7becd160ff5137f3de11975684319187e06901955f79e5a6c5a79","password":"wonderland","username":"alice"}`)
+	sharedSecret := "dendritetest"
+
+	req, err := NewSharedSecretRegistrationRequest(ioutil.NopCloser(bytes.NewBuffer(jsonStr)))
+	if err != nil {
+		t.Fatalf("failed to read request: %s", err)
+	}
+
+	r := NewSharedSecretRegistration(sharedSecret)
+
+	// force the nonce to be known
+	r.nonces.Set(req.Nonce, true, cache.DefaultExpiration)
+
+	valid, err := r.IsValidMacLogin(req.Nonce, req.User, req.Password, req.Admin, req.MacBytes)
+	if err != nil {
+		t.Fatalf("failed to check for valid mac: %s", err)
+	}
+	if !valid {
+		t.Errorf("mac login failed, wanted success")
+	}
+
+	// modify the mac so it fails
+	req.MacBytes[0] = 0xff
+	valid, err = r.IsValidMacLogin(req.Nonce, req.User, req.Password, req.Admin, req.MacBytes)
+	if err != nil {
+		t.Fatalf("failed to check for valid mac: %s", err)
+	}
+	if valid {
+		t.Errorf("mac login succeeded, wanted failure")
+	}
+}
diff --git a/clientapi/routing/routing.go b/clientapi/routing/routing.go
index 9f980e0a..37279e8e 100644
--- a/clientapi/routing/routing.go
+++ b/clientapi/routing/routing.go
@@ -37,6 +37,7 @@ import (
 	"github.com/matrix-org/dendrite/userapi/storage/accounts"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/util"
+	"github.com/sirupsen/logrus"
 )
 
 // Setup registers HTTP handlers with the given ServeMux. It also supplies the given http.Client
@@ -46,7 +47,7 @@ import (
 // applied:
 // nolint: gocyclo
 func Setup(
-	publicAPIMux *mux.Router, cfg *config.ClientAPI,
+	publicAPIMux, synapseAdminRouter *mux.Router, cfg *config.ClientAPI,
 	eduAPI eduServerAPI.EDUServerInputAPI,
 	rsAPI roomserverAPI.RoomserverInternalAPI,
 	asAPI appserviceAPI.AppServiceQueryAPI,
@@ -88,6 +89,32 @@ func Setup(
 		}),
 	).Methods(http.MethodGet, http.MethodOptions)
 
+	if cfg.RegistrationSharedSecret != "" {
+		logrus.Info("Enabling shared secret registration at /_synapse/admin/v1/register")
+		sr := NewSharedSecretRegistration(cfg.RegistrationSharedSecret)
+		synapseAdminRouter.Handle("/admin/v1/register",
+			httputil.MakeExternalAPI("shared_secret_registration", func(req *http.Request) util.JSONResponse {
+				if req.Method == http.MethodGet {
+					return util.JSONResponse{
+						Code: 200,
+						JSON: struct {
+							Nonce string `json:"nonce"`
+						}{
+							Nonce: sr.GenerateNonce(),
+						},
+					}
+				}
+				if req.Method == http.MethodPost {
+					return handleSharedSecretRegistration(userAPI, sr, req)
+				}
+				return util.JSONResponse{
+					Code: http.StatusMethodNotAllowed,
+					JSON: jsonerror.NotFound("unknown method"),
+				}
+			}),
+		).Methods(http.MethodGet, http.MethodPost, http.MethodOptions)
+	}
+
 	r0mux := publicAPIMux.PathPrefix("/r0").Subrouter()
 	unstableMux := publicAPIMux.PathPrefix("/unstable").Subrouter()
 
diff --git a/cmd/dendrite-demo-libp2p/main.go b/cmd/dendrite-demo-libp2p/main.go
index cc7dcf02..6b0e57d8 100644
--- a/cmd/dendrite-demo-libp2p/main.go
+++ b/cmd/dendrite-demo-libp2p/main.go
@@ -197,6 +197,7 @@ func main() {
 		base.Base.PublicFederationAPIMux,
 		base.Base.PublicKeyAPIMux,
 		base.Base.PublicMediaAPIMux,
+		base.Base.SynapseAdminMux,
 	)
 	if err := mscs.Enable(&base.Base, &monolith); err != nil {
 		logrus.WithError(err).Fatalf("Failed to enable MSCs")
diff --git a/cmd/dendrite-demo-pinecone/main.go b/cmd/dendrite-demo-pinecone/main.go
index 72936e42..2712ed4a 100644
--- a/cmd/dendrite-demo-pinecone/main.go
+++ b/cmd/dendrite-demo-pinecone/main.go
@@ -210,6 +210,7 @@ func main() {
 		base.PublicFederationAPIMux,
 		base.PublicKeyAPIMux,
 		base.PublicMediaAPIMux,
+		base.SynapseAdminMux,
 	)
 
 	wsUpgrader := websocket.Upgrader{
diff --git a/cmd/dendrite-demo-yggdrasil/main.go b/cmd/dendrite-demo-yggdrasil/main.go
index 2d710ae7..abeefbe5 100644
--- a/cmd/dendrite-demo-yggdrasil/main.go
+++ b/cmd/dendrite-demo-yggdrasil/main.go
@@ -154,6 +154,7 @@ func main() {
 		base.PublicFederationAPIMux,
 		base.PublicKeyAPIMux,
 		base.PublicMediaAPIMux,
+		base.SynapseAdminMux,
 	)
 	if err := mscs.Enable(base, &monolith); err != nil {
 		logrus.WithError(err).Fatalf("Failed to enable MSCs")
diff --git a/cmd/dendrite-monolith-server/main.go b/cmd/dendrite-monolith-server/main.go
index ef349505..5efbe856 100644
--- a/cmd/dendrite-monolith-server/main.go
+++ b/cmd/dendrite-monolith-server/main.go
@@ -149,6 +149,7 @@ func main() {
 		base.PublicFederationAPIMux,
 		base.PublicKeyAPIMux,
 		base.PublicMediaAPIMux,
+		base.SynapseAdminMux,
 	)
 
 	if len(base.Cfg.MSCs.MSCs) > 0 {
diff --git a/cmd/dendrite-polylith-multi/personalities/clientapi.go b/cmd/dendrite-polylith-multi/personalities/clientapi.go
index ec445ceb..5e0c4354 100644
--- a/cmd/dendrite-polylith-multi/personalities/clientapi.go
+++ b/cmd/dendrite-polylith-multi/personalities/clientapi.go
@@ -33,7 +33,7 @@ func ClientAPI(base *setup.BaseDendrite, cfg *config.Dendrite) {
 	keyAPI := base.KeyServerHTTPClient()
 
 	clientapi.AddPublicRoutes(
-		base.PublicClientAPIMux, &base.Cfg.ClientAPI, accountDB, federation,
+		base.PublicClientAPIMux, base.SynapseAdminMux, &base.Cfg.ClientAPI, accountDB, federation,
 		rsAPI, eduInputAPI, asQuery, transactions.New(), fsAPI, userAPI, keyAPI, nil,
 		&cfg.MSCs,
 	)
diff --git a/cmd/dendritejs-pinecone/main.go b/cmd/dendritejs-pinecone/main.go
index 433e9bf8..25e49690 100644
--- a/cmd/dendritejs-pinecone/main.go
+++ b/cmd/dendritejs-pinecone/main.go
@@ -215,6 +215,7 @@ func main() {
 		base.PublicFederationAPIMux,
 		base.PublicKeyAPIMux,
 		base.PublicMediaAPIMux,
+		base.SynapseAdminMux,
 	)
 
 	httpRouter := mux.NewRouter().SkipClean(true).UseEncodedPath()
diff --git a/cmd/dendritejs/main.go b/cmd/dendritejs/main.go
index 7ece94ff..d5a845ae 100644
--- a/cmd/dendritejs/main.go
+++ b/cmd/dendritejs/main.go
@@ -236,6 +236,7 @@ func main() {
 		base.PublicFederationAPIMux,
 		base.PublicKeyAPIMux,
 		base.PublicMediaAPIMux,
+		base.SynapseAdminMux,
 	)
 
 	httpRouter := mux.NewRouter().SkipClean(true).UseEncodedPath()
diff --git a/go.mod b/go.mod
index 6e227e6c..eeb4a784 100644
--- a/go.mod
+++ b/go.mod
@@ -39,6 +39,7 @@ require (
 	github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646
 	github.com/ngrok/sqlmw v0.0.0-20200129213757-d5c93a81bec6
 	github.com/opentracing/opentracing-go v1.2.0
+	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/pkg/errors v0.9.1
 	github.com/pressly/goose v2.7.0+incompatible
 	github.com/prometheus/client_golang v1.9.0
diff --git a/go.sum b/go.sum
index 6bf4632e..767826e7 100644
--- a/go.sum
+++ b/go.sum
@@ -1256,6 +1256,8 @@ github.com/openzipkin/zipkin-go v0.2.1/go.mod h1:NaW6tEwdmWMaCDZzg8sh+IBNOxHMPnh
 github.com/openzipkin/zipkin-go v0.2.2/go.mod h1:NaW6tEwdmWMaCDZzg8sh+IBNOxHMPnhQw8ySjnjRyN4=
 github.com/pact-foundation/pact-go v1.0.4/go.mod h1:uExwJY4kCzNPcHRj+hCR/HBbOOIwwtUjcrb0b5/5kLM=
 github.com/pascaldekloe/goe v0.0.0-20180627143212-57f6aae5913c/go.mod h1:lzWF7FIEvWOWxwDKqyGYQf6ZUaNfKdP144TG7ZOy1lc=
+github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
+github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
 github.com/pborman/uuid v1.2.0/go.mod h1:X/NO0urCmaxf9VXbdlT7C2Yzkj2IKimNn4k+gtPdI/k=
 github.com/pelletier/go-toml v1.2.0/go.mod h1:5z9KED0ma1S8pY6P1sdut58dfprrGBbd/94hg7ilaic=
 github.com/pelletier/go-toml v1.8.1/go.mod h1:T2/BmBdy8dvIRq1a/8aqjN41wvWlN4lrapLU/GW4pbc=
diff --git a/setup/base.go b/setup/base.go
index 6bdeb80f..7b691608 100644
--- a/setup/base.go
+++ b/setup/base.go
@@ -77,6 +77,7 @@ type BaseDendrite struct {
 	PublicKeyAPIMux        *mux.Router
 	PublicMediaAPIMux      *mux.Router
 	InternalAPIMux         *mux.Router
+	SynapseAdminMux        *mux.Router
 	UseHTTPAPIs            bool
 	apiHttpClient          *http.Client
 	httpClient             *http.Client
@@ -199,6 +200,7 @@ func NewBaseDendrite(cfg *config.Dendrite, componentName string, useHTTPAPIs boo
 		PublicKeyAPIMux:        mux.NewRouter().SkipClean(true).PathPrefix(httputil.PublicKeyPathPrefix).Subrouter().UseEncodedPath(),
 		PublicMediaAPIMux:      mux.NewRouter().SkipClean(true).PathPrefix(httputil.PublicMediaPathPrefix).Subrouter().UseEncodedPath(),
 		InternalAPIMux:         mux.NewRouter().SkipClean(true).PathPrefix(httputil.InternalPathPrefix).Subrouter().UseEncodedPath(),
+		SynapseAdminMux:        mux.NewRouter().SkipClean(true).PathPrefix("/_synapse/").Subrouter().UseEncodedPath(),
 		apiHttpClient:          &apiClient,
 		httpClient:             &client,
 	}
@@ -391,6 +393,7 @@ func (b *BaseDendrite) SetupAndServeHTTP(
 		externalRouter.PathPrefix(httputil.PublicKeyPathPrefix).Handler(b.PublicKeyAPIMux)
 		externalRouter.PathPrefix(httputil.PublicFederationPathPrefix).Handler(federationHandler)
 	}
+	externalRouter.PathPrefix("/_synapse/").Handler(b.SynapseAdminMux)
 	externalRouter.PathPrefix(httputil.PublicMediaPathPrefix).Handler(b.PublicMediaAPIMux)
 
 	if internalAddr != NoListener && internalAddr != externalAddr {
diff --git a/setup/monolith.go b/setup/monolith.go
index 235be447..5ceb4ed3 100644
--- a/setup/monolith.go
+++ b/setup/monolith.go
@@ -57,9 +57,9 @@ type Monolith struct {
 }
 
 // AddAllPublicRoutes attaches all public paths to the given router
-func (m *Monolith) AddAllPublicRoutes(process *process.ProcessContext, csMux, ssMux, keyMux, mediaMux *mux.Router) {
+func (m *Monolith) AddAllPublicRoutes(process *process.ProcessContext, csMux, ssMux, keyMux, mediaMux, synapseMux *mux.Router) {
 	clientapi.AddPublicRoutes(
-		csMux, &m.Config.ClientAPI, m.AccountDB,
+		csMux, synapseMux, &m.Config.ClientAPI, m.AccountDB,
 		m.FedClient, m.RoomserverAPI,
 		m.EDUInternalAPI, m.AppserviceAPI, transactions.New(),
 		m.FederationSenderAPI, m.UserAPI, m.KeyAPI, m.ExtPublicRoomsProvider,