SECURITY: Remove ember-cli specific response from application routes (#15155)

Under some conditions, these varied responses could lead to cache poisoning, hence the 'security' label.

Previously the Rails application would serve JSON data in place of HTML whenever Ember CLI requested an `application.html.erb`-rendered page. This commit removes that logic, and instead parses the HTML out of the standard response. This means that Rails doesn't need to customize its response for Ember CLI.
This commit is contained in:
David Taylor
2021-12-01 16:10:40 +00:00
committed by GitHub
parent f37375f582
commit 1fa7a87f86
11 changed files with 265 additions and 77 deletions
@@ -6,6 +6,7 @@ const { encode } = require("html-entities");
const cleanBaseURL = require("clean-base-url");
const path = require("path");
const { promises: fs } = require("fs");
const { JSDOM } = require("jsdom");
// via https://stackoverflow.com/a/6248722/165668
function generateUID() {
@@ -168,12 +169,14 @@ function replaceIn(bootstrap, template, id, headers, baseURL) {
return template.replace(`<bootstrap-content key="${id}">`, contents);
}
async function applyBootstrap(bootstrap, template, response, baseURL) {
// If our initial page added some preload data let's not lose that.
let json = await response.json();
if (json && json.preloaded) {
bootstrap.preloaded = Object.assign(json.preloaded, bootstrap.preloaded);
}
function extractPreloadJson(html) {
const dom = new JSDOM(html);
return dom.window.document.querySelector("#data-preloaded")?.dataset
?.preloaded;
}
async function applyBootstrap(bootstrap, template, response, baseURL, preload) {
bootstrap.preloaded = Object.assign(JSON.parse(preload), bootstrap.preloaded);
Object.keys(BUILDERS).forEach((id) => {
template = replaceIn(bootstrap, template, id, response.headers, baseURL);
@@ -181,23 +184,20 @@ async function applyBootstrap(bootstrap, template, response, baseURL) {
return template;
}
async function buildFromBootstrap(proxy, baseURL, req, response) {
async function buildFromBootstrap(proxy, baseURL, req, response, preload) {
try {
const template = await fs.readFile(
path.join(process.cwd(), "dist", "index.html"),
"utf8"
);
let url = `${proxy}${baseURL}bootstrap.json`;
const queryLoc = req.url.indexOf("?");
if (queryLoc !== -1) {
url += req.url.substr(queryLoc);
}
let url = new URL(`${proxy}${baseURL}bootstrap.json`);
url.searchParams.append("for_url", req.url);
const res = await fetch(url, { headers: req.headers });
const json = await res.json();
return applyBootstrap(json.bootstrap, template, response, baseURL);
return applyBootstrap(json.bootstrap, template, response, baseURL, preload);
} catch (error) {
throw new Error(
`Could not get ${proxy}${baseURL}bootstrap.json\n\n${error}`
@@ -229,7 +229,6 @@ async function handleRequest(proxy, baseURL, req, res) {
if (req.method === "GET") {
req.headers["X-Discourse-Ember-CLI"] = "true";
req.headers["X-Discourse-Asset-Path"] = req.path;
}
const response = await fetch(url, {
@@ -251,20 +250,37 @@ async function handleRequest(proxy, baseURL, req, res) {
const csp = response.headers.get("content-security-policy");
if (csp) {
const newCSP = csp.replace(
new RegExp(proxy, "g"),
`http://${originalHost}`
);
const emberCliAdditions = [
`http://${originalHost}/assets/`,
`http://${originalHost}/ember-cli-live-reload.js`,
`http://${originalHost}/_lr/`,
];
const newCSP = csp
.replace(new RegExp(proxy, "g"), `http://${originalHost}`)
.replace(
new RegExp("script-src ", "g"),
`script-src ${emberCliAdditions.join(" ")} `
);
res.set("content-security-policy", newCSP);
}
if (response.headers.get("x-discourse-bootstrap-required") === "true") {
const html = await buildFromBootstrap(proxy, baseURL, req, response);
const isHTML = response.headers["content-type"]?.startsWith("text/html");
const responseText = await response.text();
const preload = isHTML ? extractPreloadJson(responseText) : null;
if (preload) {
const html = await buildFromBootstrap(
proxy,
baseURL,
req,
response,
preload
);
res.set("content-type", "text/html");
res.send(html);
} else {
res.status(response.status);
res.send(await response.text());
res.send(responseText);
}
}