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272 lines (244 loc) · 9.3 KB
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const dns = require("node:dns");
const fs = require("node:fs");
const path = require("node:path");
const ipaddr = require("ipaddr.js");
const undici = require("undici");
const Log = require("logger");
const startUp = new Date();
/**
* Gets the startup time.
* @param {Request} req - the request
* @param {Response} res - the result
*/
function getStartup (req, res) {
res.send(startUp);
}
/**
* Replace `**SECRET_ABC**` placeholders with the value of `process.env.SECRET_ABC`.
*
* If `allowedSecrets` is given, only those secret names are restored and every
* other placeholder is left untouched. Without it, all secrets are restored
* (used by the CORS proxy, which only runs on the trusted server side).
* @param {string} input - String that may contain `**SECRET_***` placeholders.
* @param {Set<string>} [allowedSecrets] - Secret names that may be restored.
* @returns {string} The input with the allowed placeholders replaced.
*/
function replaceSecretPlaceholder (input, allowedSecrets) {
if (global.config.cors === "allowAll") {
if (input.includes("**SECRET_")) {
Log.error("Replacing secrets doesn't work with CORS `allowAll`, you need to set `cors` to `disabled` or `allowWhitelist` in `config.js`");
}
return input;
}
return input.replaceAll(/\*\*(SECRET_[^*]+)\*\*/g, (placeholder, secretName) => {
// Block replacing secrets that are not explicitly allowed.
if (allowedSecrets && !allowedSecrets.has(secretName)) {
return placeholder;
}
// Load the real value from the environment. Fallback to placeholder if missing.
return process.env[secretName] || placeholder;
});
}
/**
* A method that forwards HTTP Get-methods to the internet to avoid CORS-errors.
*
* Example input request url: /cors?sendheaders=header1:value1,header2:value2&expectedheaders=header1,header2&url=http://www.test.com/path?param1=value1
*
* Only the url-param of the input request url is required. It must be the last parameter.
* @param {Request} req - the request
* @param {Response} res - the result
* @returns {Promise<void>} A promise that resolves when the response is sent
*/
async function cors (req, res) {
if (global.config.cors === "disabled") {
Log.error("CORS is disabled, you need to enable it in `config.js` by setting `cors` to `allowAll` or `allowWhitelist`");
return res.status(403).json({ error: "CORS proxy is disabled" });
}
let url;
try {
const urlRegEx = "url=(.+?)$";
const match = new RegExp(urlRegEx, "g").exec(req.url);
if (!match) {
url = `invalid url: ${req.url}`;
Log.error(url);
return res.status(400).send(url);
} else {
url = match[1];
if (typeof global.config !== "undefined") {
if (config.hideConfigSecrets) {
url = replaceSecretPlaceholder(url);
}
}
// Validate protocol before attempting connection (non-http/https are never allowed)
let parsed;
try {
parsed = new URL(url);
} catch {
Log.warn(`SSRF blocked (invalid URL): ${url}`);
return res.status(403).json({ error: "Forbidden: private or reserved addresses are not allowed" });
}
if (parsed.protocol !== "http:" && parsed.protocol !== "https:") {
Log.warn(`SSRF blocked (protocol): ${url}`);
return res.status(403).json({ error: "Forbidden: private or reserved addresses are not allowed" });
}
// Block localhost by hostname before even creating the dispatcher (no DNS needed).
if (parsed.hostname.toLowerCase() === "localhost") {
Log.warn(`SSRF blocked (localhost): ${url}`);
return res.status(403).json({ error: "Forbidden: private or reserved addresses are not allowed" });
}
// Whitelist check: if enabled, only allow explicitly listed domains
if (global.config.cors === "allowWhitelist" && !global.config.corsDomainWhitelist.includes(parsed.hostname.toLowerCase())) {
Log.warn(`CORS blocked (not in whitelist): ${url}`);
return res.status(403).json({ error: "Forbidden: domain not in corsDomainWhitelist" });
}
const headersToSend = getHeadersToSend(req.url);
const expectedReceivedHeaders = geExpectedReceivedHeaders(req.url);
Log.log(`cors url: ${url}`);
// Resolve DNS once and validate the IP. The validated IP is then pinned
// for the actual connection so fetch() cannot re-resolve to a different
// address. This prevents DNS rebinding / TOCTOU attacks (GHSA-xhvw-r95j-xm4v).
const { address, family } = await dns.promises.lookup(parsed.hostname);
if (ipaddr.process(address).range() !== "unicast") {
Log.warn(`SSRF blocked: ${url}`);
return res.status(403).json({ error: "Forbidden: private or reserved addresses are not allowed" });
}
// Pin the validated IP — fetch() reuses it instead of doing its own DNS lookup
const dispatcher = new undici.Agent({
connect: {
lookup: (_h, _o, cb) => {
const addresses = [{ address: address, family: family }];
process.nextTick(() => cb(null, addresses));
}
}
});
const response = await undici.fetch(url, { dispatcher, headers: headersToSend });
if (response.ok) {
for (const header of expectedReceivedHeaders) {
const headerValue = response.headers.get(header);
if (header) res.set(header, headerValue);
}
const arrayBuffer = await response.arrayBuffer();
res.send(Buffer.from(arrayBuffer));
} else {
throw new Error(`Response status: ${response.status}`);
}
}
} catch (error) {
if (process.env.mmTestMode !== "true") {
Log.error(`Error in CORS request: ${error}`);
}
res.status(500).json({ error: error.message });
}
}
/**
* Gets headers and values to attach to the web request.
* @param {string} url - The url containing the headers and values to send.
* @returns {object} An object specifying name and value of the headers.
*/
function getHeadersToSend (url) {
const headersToSend = { "User-Agent": getUserAgent() };
const headersToSendMatch = new RegExp("sendheaders=(.+?)(&|$)", "g").exec(url);
if (headersToSendMatch) {
const headers = headersToSendMatch[1].split(",");
for (const header of headers) {
const keyValue = header.split(":");
if (keyValue.length !== 2) {
throw new Error(`Invalid format for header ${header}`);
}
headersToSend[keyValue[0]] = decodeURIComponent(keyValue[1]);
}
}
return headersToSend;
}
/**
* Gets the headers expected from the response.
* @param {string} url - The url containing the expected headers from the response.
* @returns {string[]} headers - The name of the expected headers.
*/
function geExpectedReceivedHeaders (url) {
const expectedReceivedHeaders = ["Content-Type"];
const expectedReceivedHeadersMatch = new RegExp("expectedheaders=(.+?)(&|$)", "g").exec(url);
if (expectedReceivedHeadersMatch) {
const headers = expectedReceivedHeadersMatch[1].split(",");
for (const header of headers) {
expectedReceivedHeaders.push(header);
}
}
return expectedReceivedHeaders;
}
/**
* Gets the HTML to display the magic mirror.
* @param {Request} req - the request
* @param {Response} res - the result
*/
function getHtml (req, res) {
let html = fs.readFileSync(path.resolve(`${global.root_path}/index.html`), { encoding: "utf8" });
html = html.replace("#VERSION#", global.version);
html = html.replace("#TESTMODE#", global.mmTestMode);
res.send(html);
}
/**
* Gets the MagicMirror version.
* @param {Request} req - the request
* @param {Response} res - the result
*/
function getVersion (req, res) {
res.send(global.version);
}
/**
* Gets the preferred `User-Agent`
* @returns {string} `User-Agent` to be used
*/
function getUserAgent () {
const defaultUserAgent = `Mozilla/5.0 (Node.js ${Number(process.version.match(/^v(\d+\.\d+)/)[1])}) MagicMirror/${global.version}`;
if (typeof global.config === "undefined") {
return defaultUserAgent;
}
switch (typeof global.config.userAgent) {
case "function":
return global.config.userAgent();
case "string":
return global.config.userAgent;
default:
return defaultUserAgent;
}
}
/**
* Gets environment variables needed in the browser.
* @returns {object} environment variables key: values
*/
function getEnvVarsAsObj () {
const obj = { modulesDir: `${global.config.foreignModulesDir}`, defaultModulesDir: `${global.config.defaultModulesDir}`, customCss: `${global.config.customCss}` };
if (process.env.MM_MODULES_DIR) {
obj.modulesDir = process.env.MM_MODULES_DIR.replace(`${global.root_path}/`, "");
}
if (process.env.MM_CUSTOMCSS_FILE) {
obj.customCss = process.env.MM_CUSTOMCSS_FILE.replace(`${global.root_path}/`, "");
}
return obj;
}
/**
* Gets environment variables needed in the browser.
* @param {Request} req - the request
* @param {Response} res - the result
*/
function getEnvVars (req, res) {
const obj = getEnvVarsAsObj();
res.send(obj);
}
/**
* Get the config file path from environment or default location
* @returns {string} The absolute config file path
*/
function getConfigFilePath () {
// Ensure root_path is set (for standalone contexts like watcher)
if (!global.root_path) {
global.root_path = path.resolve(`${__dirname}/../`);
}
// Check environment variable if global not set
if (!global.configuration_file && process.env.MM_CONFIG_FILE) {
global.configuration_file = process.env.MM_CONFIG_FILE;
}
return path.resolve(global.configuration_file || `${global.root_path}/config/config.js`);
}
module.exports = { cors, getHtml, getVersion, getStartup, getEnvVars, getEnvVarsAsObj, getUserAgent, getConfigFilePath, replaceSecretPlaceholder };