Encode URLs properly (#728)

We were escaping the URL before performing any pattern matching on it.
This meant that if you sent data that URLdecoded to a "/", it would count as
a "/" in the URL, potentially causing a 404. This was causing some flaky tests
with some randomly-generated query parameters.

Now, we keep URLs encoded while doing the pattern matching, and only afterwards
do we URL decode each query parameter individually before passing them to their
respective handler functions.

github.com/gorilla/mux was also updated to v1.7.3 to fix a bug with URL encoding and subrouters.

1 files changed, 16 insertions, 3 deletions

diff --git a/syncapi/routing/routing.go b/syncapi/routing/routing.go
index 93d939c3..cbdcfb6b 100644
--- a/syncapi/routing/routing.go
+++ b/syncapi/routing/routing.go
@@ -30,6 +30,10 @@ import (
 const pathPrefixR0 = "/_matrix/client/r0"
 
 // Setup configures the given mux with sync-server listeners
+//
+// Due to Setup being used to call many other functions, a gocyclo nolint is
+// applied:
+// nolint: gocyclo
 func Setup(apiMux *mux.Router, srp *sync.RequestPool, syncDB *storage.SyncServerDatabase, deviceDB *devices.Database) {
 	r0mux := apiMux.PathPrefix(pathPrefixR0).Subrouter()
 
@@ -45,17 +49,26 @@ func Setup(apiMux *mux.Router, srp *sync.RequestPool, syncDB *storage.SyncServer
 	})).Methods(http.MethodGet, http.MethodOptions)
 
 	r0mux.Handle("/rooms/{roomID}/state", common.MakeAuthAPI("room_state", authData, func(req *http.Request, device *authtypes.Device) util.JSONResponse {
-		vars := mux.Vars(req)
+		vars, err := common.URLDecodeMapValues(mux.Vars(req))
+		if err != nil {
+			return util.ErrorResponse(err)
+		}
 		return OnIncomingStateRequest(req, syncDB, vars["roomID"])
 	})).Methods(http.MethodGet, http.MethodOptions)
 
 	r0mux.Handle("/rooms/{roomID}/state/{type}", common.MakeAuthAPI("room_state", authData, func(req *http.Request, device *authtypes.Device) util.JSONResponse {
-		vars := mux.Vars(req)
+		vars, err := common.URLDecodeMapValues(mux.Vars(req))
+		if err != nil {
+			return util.ErrorResponse(err)
+		}
 		return OnIncomingStateTypeRequest(req, syncDB, vars["roomID"], vars["type"], "")
 	})).Methods(http.MethodGet, http.MethodOptions)
 
 	r0mux.Handle("/rooms/{roomID}/state/{type}/{stateKey}", common.MakeAuthAPI("room_state", authData, func(req *http.Request, device *authtypes.Device) util.JSONResponse {
-		vars := mux.Vars(req)
+		vars, err := common.URLDecodeMapValues(mux.Vars(req))
+		if err != nil {
+			return util.ErrorResponse(err)
+		}
 		return OnIncomingStateTypeRequest(req, syncDB, vars["roomID"], vars["type"], vars["stateKey"])
 	})).Methods(http.MethodGet, http.MethodOptions)
 }