Encode v3 event IDs correctly
MODIFY
federationapi/routing/routing.go
federationapi/routing/routing.go
@@ -37,6 +37,9 @@ const (
)
// Setup registers HTTP handlers with the given ServeMux.
+// The provided publicAPIMux MUST have `UseEncodedPath()` enabled or else routes will incorrectly
+// path unescape twice (once from the router, once from MakeFedAPI). We need to have this enabled
+// so we can decode paths like foo/bar%2Fbaz as [foo, bar/baz] - by default it will decode to [foo, bar, baz]
//
// Due to Setup being used to call many other functions, a gocyclo nolint is
// applied:
@@ -76,11 +79,7 @@ func Setup(
v1fedmux.Handle("/send/{txnID}", internal.MakeFedAPI(
"federation_send", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
return Send(
httpReq, request, gomatrixserverlib.TransactionID(vars["txnID"]),
cfg, rsAPI, producer, eduProducer, keys, federation,
@@ -90,11 +89,7 @@ func Setup(
v2fedmux.Handle("/invite/{roomID}/{eventID}", internal.MakeFedAPI(
"federation_invite", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
return Invite(
httpReq, request, vars["roomID"], vars["eventID"],
cfg, producer, keys,
@@ -110,11 +105,7 @@ func Setup(
v1fedmux.Handle("/exchange_third_party_invite/{roomID}", internal.MakeFedAPI(
"exchange_third_party_invite", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
return ExchangeThirdPartyInvite(
httpReq, request, vars["roomID"], rsAPI, cfg, federation, producer,
)
@@ -123,11 +114,7 @@ func Setup(
v1fedmux.Handle("/event/{eventID}", internal.MakeFedAPI(
"federation_get_event", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
return GetEvent(
httpReq.Context(), request, rsAPI, vars["eventID"], cfg.Matrix.ServerName,
)
@@ -136,11 +123,7 @@ func Setup(
v1fedmux.Handle("/state/{roomID}", internal.MakeFedAPI(
"federation_get_state", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
return GetState(
httpReq.Context(), request, rsAPI, vars["roomID"],
)
@@ -149,11 +132,7 @@ func Setup(
v1fedmux.Handle("/state_ids/{roomID}", internal.MakeFedAPI(
"federation_get_state_ids", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
return GetStateIDs(
httpReq.Context(), request, rsAPI, vars["roomID"],
)
@@ -162,8 +141,7 @@ func Setup(
v1fedmux.Handle("/event_auth/{roomID}/{eventID}", internal.MakeFedAPI(
"federation_get_event_auth", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars := mux.Vars(httpReq)
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
return GetEventAuth(
httpReq.Context(), request, rsAPI, vars["roomID"], vars["eventID"],
)
@@ -172,7 +150,7 @@ func Setup(
v1fedmux.Handle("/query/directory", internal.MakeFedAPI(
"federation_query_room_alias", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
return RoomAliasToID(
httpReq, federation, cfg, rsAPI, fsAPI,
)
@@ -181,7 +159,7 @@ func Setup(
v1fedmux.Handle("/query/profile", internal.MakeFedAPI(
"federation_query_profile", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
return GetProfile(
httpReq, accountDB, cfg, asAPI,
)
@@ -190,11 +168,7 @@ func Setup(
v1fedmux.Handle("/user/devices/{userID}", internal.MakeFedAPI(
"federation_user_devices", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
return GetUserDevices(
httpReq, deviceDB, vars["userID"],
)
@@ -203,11 +177,7 @@ func Setup(
v1fedmux.Handle("/make_join/{roomID}/{eventID}", internal.MakeFedAPI(
"federation_make_join", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
roomID := vars["roomID"]
eventID := vars["eventID"]
queryVars := httpReq.URL.Query()
@@ -232,11 +202,7 @@ func Setup(
v1fedmux.Handle("/send_join/{roomID}/{eventID}", internal.MakeFedAPI(
"federation_send_join", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
roomID := vars["roomID"]
eventID := vars["eventID"]
res := SendJoin(
@@ -254,11 +220,7 @@ func Setup(
v2fedmux.Handle("/send_join/{roomID}/{eventID}", internal.MakeFedAPI(
"federation_send_join", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
roomID := vars["roomID"]
eventID := vars["eventID"]
return SendJoin(
@@ -269,11 +231,7 @@ func Setup(
v1fedmux.Handle("/make_leave/{roomID}/{eventID}", internal.MakeFedAPI(
"federation_make_leave", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
roomID := vars["roomID"]
eventID := vars["eventID"]
return MakeLeave(
@@ -284,11 +242,7 @@ func Setup(
v2fedmux.Handle("/send_leave/{roomID}/{eventID}", internal.MakeFedAPI(
"federation_send_leave", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
roomID := vars["roomID"]
eventID := vars["eventID"]
return SendLeave(
@@ -306,22 +260,14 @@ func Setup(
v1fedmux.Handle("/get_missing_events/{roomID}", internal.MakeFedAPI(
"federation_get_missing_events", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
return GetMissingEvents(httpReq, request, rsAPI, vars["roomID"])
},
)).Methods(http.MethodPost)
v1fedmux.Handle("/backfill/{roomID}", internal.MakeFedAPI(
"federation_backfill", cfg.Matrix.ServerName, keys, wakeup,
- func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
- vars, err := internal.URLDecodeMapValues(mux.Vars(httpReq))
- if err != nil {
- return util.ErrorResponse(err)
- }
+ func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
return Backfill(httpReq, request, rsAPI, vars["roomID"], cfg)
},
)).Methods(http.MethodGet)

MODIFY
internal/basecomponent/base.go
internal/basecomponent/base.go
@@ -103,7 +103,18 @@ func NewBaseDendrite(cfg *config.Dendrite, componentName string, enableHTTPAPIs
})}
}
- httpmux := mux.NewRouter()
+ // Ideally we would only use SkipClean on routes which we know can allow '/' but due to
+ // https://github.com/gorilla/mux/issues/460 we have to attach this at the top router.
+ // When used in conjunction with UseEncodedPath() we get the behaviour we want when parsing
+ // path parameters:
+ // /foo/bar%2Fbaz == [foo, bar%2Fbaz] (from UseEncodedPath)
+ // /foo/bar%2F%2Fbaz == [foo, bar%2F%2Fbaz] (from SkipClean)
+ // In particular, rooms v3 event IDs are not urlsafe and can include '/' and because they
+ // are randomly generated it results in flakey tests.
+ // We need to be careful with media APIs if they read from a filesystem to make sure they
+ // are not inadvertently reading paths without cleaning, else this could introduce a
+ // directory traversal attack e.g /../../../etc/passwd
+ httpmux := mux.NewRouter().SkipClean(true)
return &BaseDendrite{
componentName: componentName,

MODIFY
internal/httpapi.go
internal/httpapi.go
@@ -174,7 +174,7 @@ func MakeFedAPI(
serverName gomatrixserverlib.ServerName,
keyRing gomatrixserverlib.KeyRing,
wakeup *FederationWakeups,
- f func(*http.Request, *gomatrixserverlib.FederationRequest) util.JSONResponse,
+ f func(*http.Request, *gomatrixserverlib.FederationRequest, map[string]string) util.JSONResponse,
) http.Handler {
h := func(req *http.Request) util.JSONResponse {
fedReq, errResp := gomatrixserverlib.VerifyHTTPRequest(
@@ -184,7 +184,12 @@ func MakeFedAPI(
return errResp
}
go wakeup.Wakeup(req.Context(), fedReq.Origin())
- return f(req, fedReq)
+ vars, err := URLDecodeMapValues(mux.Vars(req))
+ if err != nil {
+ return util.ErrorResponse(err)
+ }
+
+ return f(req, fedReq, vars)
}
return MakeExternalAPI(metricsName, h)
}

Encode v3 event IDs correctly (#1090)