Ratelimit requests to /media/r0/download|upload (#2020)

* Add /media/r0/config handler

Signed-off-by: Till Faelligen <tfaelligen@gmail.com>

* Add rate limiting to media api

* Rename variable

* Add passing tests

* Don't send multiple headers

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>

7 files changed, 74 insertions, 37 deletions

diff --git a/clientapi/routing/routing.go b/clientapi/routing/routing.go
index 813d9d16..9263c66b 100644
--- a/clientapi/routing/routing.go
+++ b/clientapi/routing/routing.go
@@ -61,7 +61,7 @@ func Setup(
 	extRoomsProvider api.ExtraPublicRoomsProvider,
 	mscCfg *config.MSCs,
 ) {
-	rateLimits := newRateLimits(&cfg.RateLimiting)
+	rateLimits := httputil.NewRateLimits(&cfg.RateLimiting)
 	userInteractiveAuth := auth.NewUserInteractive(accountDB.GetAccountByPassword, cfg)
 
 	unstableFeatures := map[string]bool{
@@ -127,7 +127,7 @@ func Setup(
 	).Methods(http.MethodPost, http.MethodOptions)
 	r0mux.Handle("/join/{roomIDOrAlias}",
 		httputil.MakeAuthAPI(gomatrixserverlib.Join, userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
@@ -143,7 +143,7 @@ func Setup(
 	if mscCfg.Enabled("msc2753") {
 		r0mux.Handle("/peek/{roomIDOrAlias}",
 			httputil.MakeAuthAPI(gomatrixserverlib.Peek, userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-				if r := rateLimits.rateLimit(req); r != nil {
+				if r := rateLimits.Limit(req); r != nil {
 					return *r
 				}
 				vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
@@ -163,7 +163,7 @@ func Setup(
 	).Methods(http.MethodGet, http.MethodOptions)
 	r0mux.Handle("/rooms/{roomID}/join",
 		httputil.MakeAuthAPI(gomatrixserverlib.Join, userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
@@ -177,7 +177,7 @@ func Setup(
 	).Methods(http.MethodPost, http.MethodOptions)
 	r0mux.Handle("/rooms/{roomID}/leave",
 		httputil.MakeAuthAPI("membership", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
@@ -211,7 +211,7 @@ func Setup(
 	).Methods(http.MethodPost, http.MethodOptions)
 	r0mux.Handle("/rooms/{roomID}/invite",
 		httputil.MakeAuthAPI("membership", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
@@ -329,14 +329,14 @@ func Setup(
 	).Methods(http.MethodPut, http.MethodOptions)
 
 	r0mux.Handle("/register", httputil.MakeExternalAPI("register", func(req *http.Request) util.JSONResponse {
-		if r := rateLimits.rateLimit(req); r != nil {
+		if r := rateLimits.Limit(req); r != nil {
 			return *r
 		}
 		return Register(req, userAPI, accountDB, cfg)
 	})).Methods(http.MethodPost, http.MethodOptions)
 
 	r0mux.Handle("/register/available", httputil.MakeExternalAPI("registerAvailable", func(req *http.Request) util.JSONResponse {
-		if r := rateLimits.rateLimit(req); r != nil {
+		if r := rateLimits.Limit(req); r != nil {
 			return *r
 		}
 		return RegisterAvailable(req, cfg, accountDB)
@@ -410,7 +410,7 @@ func Setup(
 
 	r0mux.Handle("/rooms/{roomID}/typing/{userID}",
 		httputil.MakeAuthAPI("rooms_typing", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
@@ -466,7 +466,7 @@ func Setup(
 
 	r0mux.Handle("/account/whoami",
 		httputil.MakeAuthAPI("whoami", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			return Whoami(req, device)
@@ -475,7 +475,7 @@ func Setup(
 
 	r0mux.Handle("/account/password",
 		httputil.MakeAuthAPI("password", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			return Password(req, userAPI, accountDB, device, cfg)
@@ -484,7 +484,7 @@ func Setup(
 
 	r0mux.Handle("/account/deactivate",
 		httputil.MakeAuthAPI("deactivate", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			return Deactivate(req, userInteractiveAuth, userAPI, device)
@@ -495,7 +495,7 @@ func Setup(
 
 	r0mux.Handle("/login",
 		httputil.MakeExternalAPI("login", func(req *http.Request) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			return Login(req, accountDB, userAPI, cfg)
@@ -552,7 +552,7 @@ func Setup(
 
 	r0mux.Handle("/profile/{userID}/avatar_url",
 		httputil.MakeAuthAPI("profile_avatar_url", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
@@ -577,7 +577,7 @@ func Setup(
 
 	r0mux.Handle("/profile/{userID}/displayname",
 		httputil.MakeAuthAPI("profile_displayname", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
@@ -617,7 +617,7 @@ func Setup(
 	// Element logs get flooded unless this is handled
 	r0mux.Handle("/presence/{userID}/status",
 		httputil.MakeExternalAPI("presence", func(req *http.Request) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			// TODO: Set presence (probably the responsibility of a presence server not clientapi)
@@ -630,7 +630,7 @@ func Setup(
 
 	r0mux.Handle("/voip/turnServer",
 		httputil.MakeAuthAPI("turn_server", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			return RequestTurnServer(req, device, cfg)
@@ -709,7 +709,7 @@ func Setup(
 
 	r0mux.Handle("/user/{userID}/openid/request_token",
 		httputil.MakeAuthAPI("openid_request_token", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
@@ -722,7 +722,7 @@ func Setup(
 
 	r0mux.Handle("/user_directory/search",
 		httputil.MakeAuthAPI("userdirectory_search", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			postContent := struct {
@@ -767,7 +767,7 @@ func Setup(
 
 	r0mux.Handle("/rooms/{roomID}/read_markers",
 		httputil.MakeAuthAPI("rooms_read_markers", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
@@ -780,7 +780,7 @@ func Setup(
 
 	r0mux.Handle("/rooms/{roomID}/forget",
 		httputil.MakeAuthAPI("rooms_forget", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
@@ -884,7 +884,7 @@ func Setup(
 
 	r0mux.Handle("/capabilities",
 		httputil.MakeAuthAPI("capabilities", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			return GetCapabilities(req, rsAPI)
@@ -1100,7 +1100,7 @@ func Setup(
 	).Methods(http.MethodPost, http.MethodOptions)
 	r0mux.Handle("/rooms/{roomId}/receipt/{receiptType}/{eventId}",
 		httputil.MakeAuthAPI(gomatrixserverlib.Join, userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			if r := rateLimits.rateLimit(req); r != nil {
+			if r := rateLimits.Limit(req); r != nil {
 				return *r
 			}
 			vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
diff --git a/cmd/dendrite-polylith-multi/personalities/mediaapi.go b/cmd/dendrite-polylith-multi/personalities/mediaapi.go
index 00a2d56a..fa9d36a3 100644
--- a/cmd/dendrite-polylith-multi/personalities/mediaapi.go
+++ b/cmd/dendrite-polylith-multi/personalities/mediaapi.go
@@ -24,7 +24,7 @@ func MediaAPI(base *basepkg.BaseDendrite, cfg *config.Dendrite) {
 	userAPI := base.UserAPIClient()
 	client := base.CreateClient()
 
-	mediaapi.AddPublicRoutes(base.PublicMediaAPIMux, &base.Cfg.MediaAPI, userAPI, client)
+	mediaapi.AddPublicRoutes(base.PublicMediaAPIMux, &base.Cfg.MediaAPI, &base.Cfg.ClientAPI.RateLimiting, userAPI, client)
 
 	base.SetupAndServeHTTP(
 		base.Cfg.MediaAPI.InternalAPI.Listen,
diff --git a/clientapi/routing/rate_limiting.go b/internal/httputil/rate_limiting.go
index 5291caba..c4f47c7b 100644
--- a/clientapi/routing/rate_limiting.go
+++ b/internal/httputil/rate_limiting.go
@@ -1,4 +1,4 @@
-package routing
+package httputil
 
 import (
 	"net/http"
@@ -10,7 +10,7 @@ import (
 	"github.com/matrix-org/util"
 )
 
-type rateLimits struct {
+type RateLimits struct {
 	limits           map[string]chan struct{}
 	limitsMutex      sync.RWMutex
 	cleanMutex       sync.RWMutex
@@ -19,8 +19,8 @@ type rateLimits struct {
 	cooloffDuration  time.Duration
 }
 
-func newRateLimits(cfg *config.RateLimiting) *rateLimits {
-	l := &rateLimits{
+func NewRateLimits(cfg *config.RateLimiting) *RateLimits {
+	l := &RateLimits{
 		limits:           make(map[string]chan struct{}),
 		enabled:          cfg.Enabled,
 		requestThreshold: cfg.Threshold,
@@ -32,7 +32,7 @@ func newRateLimits(cfg *config.RateLimiting) *rateLimits {
 	return l
 }
 
-func (l *rateLimits) clean() {
+func (l *RateLimits) clean() {
 	for {
 		// On a 30 second interval, we'll take an exclusive write
 		// lock of the entire map and see if any of the channels are
@@ -52,7 +52,7 @@ func (l *rateLimits) clean() {
 	}
 }
 
-func (l *rateLimits) rateLimit(req *http.Request) *util.JSONResponse {
+func (l *RateLimits) Limit(req *http.Request) *util.JSONResponse {
 	// If rate limiting is disabled then do nothing.
 	if !l.enabled {
 		return nil
diff --git a/mediaapi/mediaapi.go b/mediaapi/mediaapi.go
index 811d8e4a..c010981c 100644
--- a/mediaapi/mediaapi.go
+++ b/mediaapi/mediaapi.go
@@ -26,7 +26,9 @@ import (
 
 // AddPublicRoutes sets up and registers HTTP handlers for the MediaAPI component.
 func AddPublicRoutes(
-	router *mux.Router, cfg *config.MediaAPI,
+	router *mux.Router,
+	cfg *config.MediaAPI,
+	rateLimit *config.RateLimiting,
 	userAPI userapi.UserInternalAPI,
 	client *gomatrixserverlib.Client,
 ) {
@@ -36,6 +38,6 @@ func AddPublicRoutes(
 	}
 
 	routing.Setup(
-		router, cfg, mediaDB, userAPI, client,
+		router, cfg, rateLimit, mediaDB, userAPI, client,
 	)
 }
diff --git a/mediaapi/routing/routing.go b/mediaapi/routing/routing.go
index 917a8596..44f9a9d6 100644
--- a/mediaapi/routing/routing.go
+++ b/mediaapi/routing/routing.go
@@ -15,16 +15,16 @@
 package routing
 
 import (
+	"encoding/json"
 	"net/http"
 	"strings"
 
-	userapi "github.com/matrix-org/dendrite/userapi/api"
-
 	"github.com/gorilla/mux"
 	"github.com/matrix-org/dendrite/internal/httputil"
 	"github.com/matrix-org/dendrite/mediaapi/storage"
 	"github.com/matrix-org/dendrite/mediaapi/types"
 	"github.com/matrix-org/dendrite/setup/config"
+	userapi "github.com/matrix-org/dendrite/userapi/api"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/util"
 	"github.com/prometheus/client_golang/prometheus"
@@ -32,6 +32,12 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
+// configResponse is the response to GET /_matrix/media/r0/config
+// https://matrix.org/docs/spec/client_server/latest#get-matrix-media-r0-config
+type configResponse struct {
+	UploadSize config.FileSizeBytes `json:"m.upload.size"`
+}
+
 // Setup registers the media API HTTP handlers
 //
 // Due to Setup being used to call many other functions, a gocyclo nolint is
@@ -40,10 +46,13 @@ import (
 func Setup(
 	publicAPIMux *mux.Router,
 	cfg *config.MediaAPI,
+	rateLimit *config.RateLimiting,
 	db storage.Database,
 	userAPI userapi.UserInternalAPI,
 	client *gomatrixserverlib.Client,
 ) {
+	rateLimits := httputil.NewRateLimits(rateLimit)
+
 	r0mux := publicAPIMux.PathPrefix("/r0").Subrouter()
 	v1mux := publicAPIMux.PathPrefix("/v1").Subrouter()
 
@@ -54,31 +63,46 @@ func Setup(
 	uploadHandler := httputil.MakeAuthAPI(
 		"upload", userAPI,
 		func(req *http.Request, dev *userapi.Device) util.JSONResponse {
+			if r := rateLimits.Limit(req); r != nil {
+				return *r
+			}
 			return Upload(req, cfg, dev, db, activeThumbnailGeneration)
 		},
 	)
 
+	configHandler := httputil.MakeAuthAPI("config", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
+		if r := rateLimits.Limit(req); r != nil {
+			return *r
+		}
+		return util.JSONResponse{
+			Code: http.StatusOK,
+			JSON: configResponse{UploadSize: *cfg.MaxFileSizeBytes},
+		}
+	})
+
 	r0mux.Handle("/upload", uploadHandler).Methods(http.MethodPost, http.MethodOptions)
+	r0mux.Handle("/config", configHandler).Methods(http.MethodGet, http.MethodOptions)
 	v1mux.Handle("/upload", uploadHandler).Methods(http.MethodPost, http.MethodOptions)
 
 	activeRemoteRequests := &types.ActiveRemoteRequests{
 		MXCToResult: map[string]*types.RemoteRequestResult{},
 	}
 
-	downloadHandler := makeDownloadAPI("download", cfg, db, client, activeRemoteRequests, activeThumbnailGeneration)
+	downloadHandler := makeDownloadAPI("download", cfg, rateLimits, db, client, activeRemoteRequests, activeThumbnailGeneration)
 	r0mux.Handle("/download/{serverName}/{mediaId}", downloadHandler).Methods(http.MethodGet, http.MethodOptions)
 	r0mux.Handle("/download/{serverName}/{mediaId}/{downloadName}", downloadHandler).Methods(http.MethodGet, http.MethodOptions)
 	v1mux.Handle("/download/{serverName}/{mediaId}", downloadHandler).Methods(http.MethodGet, http.MethodOptions)                // TODO: remove when synapse is fixed
 	v1mux.Handle("/download/{serverName}/{mediaId}/{downloadName}", downloadHandler).Methods(http.MethodGet, http.MethodOptions) // TODO: remove when synapse is fixed
 
 	r0mux.Handle("/thumbnail/{serverName}/{mediaId}",
-		makeDownloadAPI("thumbnail", cfg, db, client, activeRemoteRequests, activeThumbnailGeneration),
+		makeDownloadAPI("thumbnail", cfg, rateLimits, db, client, activeRemoteRequests, activeThumbnailGeneration),
 	).Methods(http.MethodGet, http.MethodOptions)
 }
 
 func makeDownloadAPI(
 	name string,
 	cfg *config.MediaAPI,
+	rateLimits *httputil.RateLimits,
 	db storage.Database,
 	client *gomatrixserverlib.Client,
 	activeRemoteRequests *types.ActiveRemoteRequests,
@@ -99,6 +123,16 @@ func makeDownloadAPI(
 		// Content-Type will be overridden in case of returning file data, else we respond with JSON-formatted errors
 		w.Header().Set("Content-Type", "application/json")
 
+		// Ratelimit requests
+		if r := rateLimits.Limit(req); r != nil {
+			if err := json.NewEncoder(w).Encode(r); err != nil {
+				w.WriteHeader(http.StatusInternalServerError)
+				return
+			}
+			w.WriteHeader(http.StatusTooManyRequests)
+			return
+		}
+
 		vars, _ := httputil.URLDecodeMapValues(mux.Vars(req))
 		serverName := gomatrixserverlib.ServerName(vars["serverName"])
 
diff --git a/setup/monolith.go b/setup/monolith.go
index b076e990..e6c95522 100644
--- a/setup/monolith.go
+++ b/setup/monolith.go
@@ -68,7 +68,7 @@ func (m *Monolith) AddAllPublicRoutes(process *process.ProcessContext, csMux, ss
 		m.KeyRing, m.RoomserverAPI, m.FederationAPI,
 		m.EDUInternalAPI, m.KeyAPI, &m.Config.MSCs, nil,
 	)
-	mediaapi.AddPublicRoutes(mediaMux, &m.Config.MediaAPI, m.UserAPI, m.Client)
+	mediaapi.AddPublicRoutes(mediaMux, &m.Config.MediaAPI, &m.Config.ClientAPI.RateLimiting, m.UserAPI, m.Client)
 	syncapi.AddPublicRoutes(
 		process, csMux, m.UserAPI, m.RoomserverAPI,
 		m.KeyAPI, m.FedClient, &m.Config.SyncAPI,
diff --git a/sytest-whitelist b/sytest-whitelist
index d074d42b..558eb29a 100644
--- a/sytest-whitelist
+++ b/sytest-whitelist
@@ -556,6 +556,7 @@ can fetch self-signing keys over federation
 Changing master key notifies local users
 Changing user-signing key notifies local users
 Inbound federation correctly handles soft failed events as extremities
+Can read configuration endpoint
 User can create and send/receive messages in a room with version 7
 local user can join room with version 7
 User can invite local user to room with version 7