const fs = require('fs') const path = require('path') const pump = require('pump') const log = require('loglevel') const Dnode = require('dnode') const querystring = require('querystring') const LocalMessageDuplexStream = require('post-message-stream') const ObjectMultiplex = require('obj-multiplex') const extension = require('extensionizer') const PortStream = require('extension-port-stream') const inpageContent = fs.readFileSync(path.join(__dirname, '..', '..', 'dist', 'chrome', 'inpage.js')).toString() const inpageSuffix = '//# sourceURL=' + extension.runtime.getURL('inpage.js') + '\n' const inpageBundle = inpageContent + inpageSuffix // Eventually this streaming injection could be replaced with: // https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Language_Bindings/Components.utils.exportFunction // // But for now that is only Firefox // If we create a FireFox-only code path using that API, // MetaMask will be much faster loading and performant on Firefox. if (shouldInjectWeb3()) { injectScript(inpageBundle) start() } /** * Injects a script tag into the current document * * @param {string} content - Code to be executed in the current document */ function injectScript (content) { try { const container = document.head || document.documentElement const scriptTag = document.createElement('script') scriptTag.setAttribute('async', false) scriptTag.textContent = content container.insertBefore(scriptTag, container.children[0]) container.removeChild(scriptTag) } catch (e) { console.error('MetaMask script injection failed', e) } } /** * Sets up the stream communication and submits site metadata * */ async function start () { await setupStreams() await domIsReady() } /** * Sets up two-way communication streams between the * browser extension and local per-page browser context. * */ async function setupStreams () { // the transport-specific streams for communication between inpage and background const pageStream = new LocalMessageDuplexStream({ name: 'contentscript', target: 'inpage', }) const extensionPort = extension.runtime.connect({ name: 'contentscript' }) const extensionStream = new PortStream(extensionPort) // create and connect channel muxers // so we can handle the channels individually const pageMux = new ObjectMultiplex() pageMux.setMaxListeners(25) const extensionMux = new ObjectMultiplex() extensionMux.setMaxListeners(25) pump( pageMux, pageStream, pageMux, (err) => logStreamDisconnectWarning('MetaMask Inpage Multiplex', err) ) pump( extensionMux, extensionStream, extensionMux, (err) => logStreamDisconnectWarning('MetaMask Background Multiplex', err) ) // forward communication across inpage-background for these channels only forwardTrafficBetweenMuxers('provider', pageMux, extensionMux) forwardTrafficBetweenMuxers('publicConfig', pageMux, extensionMux) // connect "phishing" channel to warning system const phishingStream = extensionMux.createStream('phishing') phishingStream.once('data', redirectToPhishingWarning) // connect "publicApi" channel to submit page metadata const publicApiStream = extensionMux.createStream('publicApi') const background = await setupPublicApi(publicApiStream) return { background } } function forwardTrafficBetweenMuxers (channelName, muxA, muxB) { const channelA = muxA.createStream(channelName) const channelB = muxB.createStream(channelName) pump( channelA, channelB, channelA, (err) => logStreamDisconnectWarning(`MetaMask muxed traffic for channel "${channelName}" failed.`, err) ) } async function setupPublicApi (outStream) { const api = { getSiteMetadata: (cb) => cb(null, getSiteMetadata()), } const dnode = Dnode(api) pump( outStream, dnode, outStream, (err) => { // report any error if (err) log.error(err) } ) const background = await new Promise(resolve => dnode.once('remote', resolve)) return background } /** * Gets site metadata and returns it * */ function getSiteMetadata () { // get metadata const metadata = { name: getSiteName(window), icon: getSiteIcon(window), } return metadata } /** * Error handler for page to extension stream disconnections * * @param {string} remoteLabel Remote stream name * @param {Error} err Stream connection error */ function logStreamDisconnectWarning (remoteLabel, err) { let warningMsg = `MetamaskContentscript - lost connection to ${remoteLabel}` if (err) warningMsg += '\n' + err.stack console.warn(warningMsg) } /** * Determines if Web3 should be injected * * @returns {boolean} {@code true} if Web3 should be injected */ function shouldInjectWeb3 () { return doctypeCheck() && suffixCheck() && documentElementCheck() && !blacklistedDomainCheck() } /** * Checks the doctype of the current document if it exists * * @returns {boolean} {@code true} if the doctype is html or if none exists */ function doctypeCheck () { const doctype = window.document.doctype if (doctype) { return doctype.name === 'html' } else { return true } } /** * Returns whether or not the extension (suffix) of the current document is prohibited * * This checks {@code window.location.pathname} against a set of file extensions * that should not have web3 injected into them. This check is indifferent of query parameters * in the location. * * @returns {boolean} whether or not the extension of the current document is prohibited */ function suffixCheck () { const prohibitedTypes = [ /\.xml$/, /\.pdf$/, ] const currentUrl = window.location.pathname for (let i = 0; i < prohibitedTypes.length; i++) { if (prohibitedTypes[i].test(currentUrl)) { return false } } return true } /** * Checks the documentElement of the current document * * @returns {boolean} {@code true} if the documentElement is an html node or if none exists */ function documentElementCheck () { const documentElement = document.documentElement.nodeName if (documentElement) { return documentElement.toLowerCase() === 'html' } return true } /** * Checks if the current domain is blacklisted * * @returns {boolean} {@code true} if the current domain is blacklisted */ function blacklistedDomainCheck () { const blacklistedDomains = [ 'uscourts.gov', 'dropbox.com', 'webbyawards.com', 'cdn.shopify.com/s/javascripts/tricorder/xtld-read-only-frame.html', 'adyen.com', 'gravityforms.com', 'harbourair.com', 'ani.gamer.com.tw', 'blueskybooking.com', 'sharefile.com', ] const currentUrl = window.location.href let currentRegex for (let i = 0; i < blacklistedDomains.length; i++) { const blacklistedDomain = blacklistedDomains[i].replace('.', '\\.') currentRegex = new RegExp(`(?:https?:\\/\\/)(?:(?!${blacklistedDomain}).)*$`) if (!currentRegex.test(currentUrl)) { return true } } return false } /** * Redirects the current page to a phishing information page */ function redirectToPhishingWarning () { console.log('MetaMask - routing to Phishing Warning component') const extensionURL = extension.runtime.getURL('phishing.html') window.location.href = `${extensionURL}#${querystring.stringify({ hostname: window.location.hostname, href: window.location.href, })}` } /** * Extracts a name for the site from the DOM */ function getSiteName (window) { const document = window.document const siteName = document.querySelector('head > meta[property="og:site_name"]') if (siteName) { return siteName.content } const metaTitle = document.querySelector('head > meta[name="title"]') if (metaTitle) { return metaTitle.content } return document.title } /** * Extracts an icon for the site from the DOM */ function getSiteIcon (window) { const document = window.document // Use the site's favicon if it exists const shortcutIcon = document.querySelector('head > link[rel="shortcut icon"]') if (shortcutIcon) { return shortcutIcon.href } // Search through available icons in no particular order const icon = Array.from(document.querySelectorAll('head > link[rel="icon"]')).find((icon) => Boolean(icon.href)) if (icon) { return icon.href } return null } /** * Returns a promise that resolves when the DOM is loaded (does not wait for images to load) */ async function domIsReady () { // already loaded if (['interactive', 'complete'].includes(document.readyState)) return // wait for load await new Promise(resolve => window.addEventListener('DOMContentLoaded', resolve, { once: true })) }