Add origin checks to web sockets (#6048)

* Move splitOnFirstEquals to util

I will be making use of this to parse the forwarded header.

* Type splitOnFirstEquals with two items

Also add some test cases.

* Check origin header on web sockets

* Update changelog with origin check

* Fix web sockets not closing with error code

src/node/routes/pathProxy.ts

@@ -3,7 +3,7 @@ import * as path from "path"
 import * as qs from "qs"
 import * as pluginapi from "../../../typings/pluginapi"
 import { HttpCode, HttpError } from "../../common/http"
-import { authenticated, ensureAuthenticated, redirect, self } from "../http"
+import { authenticated, ensureAuthenticated, ensureOrigin, redirect, self } from "../http"
 import { proxy as _proxy } from "../proxy"
 
 const getProxyTarget = (req: Request, passthroughPath?: boolean): string => {
@@ -50,6 +50,7 @@ export async function wsProxy(
     passthroughPath?: boolean
   },
 ): Promise<void> {
+  ensureOrigin(req)
   await ensureAuthenticated(req)
   _proxy.ws(req, req.ws, req.head, {
     ignorePath: true,