Don't change URL when showing 403 error page

frontend/src/metabase/App.jsx

 /* @flow weak */
 
 import React, { Component, PropTypes } from "react";
+import { connect } from "react-redux";
 
 import Navbar from "metabase/nav/containers/Navbar.jsx";
 
 import UndoListing from "metabase/containers/UndoListing";
 
+import NotFound from "metabase/components/NotFound.jsx";
+import Unauthorized from "metabase/components/Unauthorized.jsx";
+
+const mapStateToProps = (state, props) => ({
+    errorPage: state.app.errorPage
+})
+
+@connect(mapStateToProps)
 export default class App extends Component {
     render() {
-        const { children, location } = this.props;
+        const { children, location, errorPage } = this.props;
         return (
             <div className="spread flex flex-column">
                 <Navbar location={location} className="flex-no-shrink" />
-                {children}
+                { errorPage === 403 ?
+                    <Unauthorized />
+                : errorPage === 404 ?
+                    <NotFound />
+                :
+                    children
+                }
                 <UndoListing />
             </div>
         )

frontend/src/metabase/app.js

@@ -13,6 +13,7 @@ import { getRoutes } from "./routes.jsx";
 import { getStore } from './store'
 
 import { refreshSiteSettings } from "metabase/redux/settings";
+import { setErrorPage } from "metabase/redux/app";
 
 import { Router, browserHistory } from "react-router";
 import { push, syncHistoryWithStore } from 'react-router-redux'
@@ -63,7 +64,7 @@ function init() {
                 }
             }
         }
-        store.dispatch(push("/unauthorized"));
+        store.dispatch(setErrorPage(403));
     });
 }
 

frontend/src/metabase/reducers.js

@@ -5,6 +5,7 @@ import { combineReducers } from 'redux';
 import auth from "metabase/auth/auth";
 
 /* ducks */
+import app from "metabase/redux/app";
 import metadata from "metabase/redux/metadata";
 import requests from "metabase/redux/requests";
 import undo from "metabase/redux/undo";
@@ -41,6 +42,7 @@ import { currentUser } from "metabase/redux/user";
 
 const reducers = {
     // global reducers
+    app,
     auth,
     currentUser,
     metadata,

frontend/src/metabase/redux/app.js

+import { combineReducers, handleActions, createAction } from "metabase/lib/redux";
+
+import { LOCATION_CHANGE } from "react-router-redux"
+
+export const SET_ERROR_PAGE = "metabase/app/SET_ERROR_PAGE";
+
+export const setErrorPage = createAction(SET_ERROR_PAGE);
+
+const errorPage = handleActions({
+    [SET_ERROR_PAGE]: (state, { payload }) => payload,
+    [LOCATION_CHANGE]: () => null
+}, null);
+
+export default combineReducers({
+    errorPage
+});