const fs = require('fs') const path = require('path') const pump = require('pump') const querystring = require('querystring') const LocalMessageDuplexStream = require('post-message-stream') const PongStream = require('ping-pong-stream/pong') const ObjectMultiplex = require('obj-multiplex') const extension = require('extensionizer') const PortStream = require('extension-port-stream') const TransformStream = require('stream').Transform const inpageContent = fs.readFileSync(path.join(__dirname, '..', '..', 'dist', 'chrome', 'inpage.js')).toString() const inpageSuffix = '//# sourceURL=' + extension.extension.getURL('inpage.js') + '\n' const inpageBundle = inpageContent + inpageSuffix let isEnabled = false // 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) setupStreams() listenForProviderRequest() checkPrivacyMode() } /** * 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.textContent = content container.insertBefore(scriptTag, container.children[0]) } catch (e) { console.error('MetaMask script injection failed', e) } } /** * Sets up two-way communication streams between the * browser extension and local per-page browser context */ function setupStreams () { // setup communication to page and plugin const pageStream = new LocalMessageDuplexStream({ name: 'contentscript', target: 'inpage', }) const pluginPort = extension.runtime.connect({ name: 'contentscript' }) const pluginStream = new PortStream(pluginPort) // Filter out selectedAddress until this origin is enabled const approvalTransform = new TransformStream({ objectMode: true, transform: (data, _, done) => { if (typeof data === 'object' && data.name && data.name === 'publicConfig' && !isEnabled) { data.data.selectedAddress = undefined } done(null, { ...data }) }, }) // forward communication plugin->inpage pump( pageStream, pluginStream, approvalTransform, pageStream, (err) => logStreamDisconnectWarning('MetaMask Contentscript Forwarding', err) ) // setup local multistream channels const mux = new ObjectMultiplex() mux.setMaxListeners(25) pump( mux, pageStream, mux, (err) => logStreamDisconnectWarning('MetaMask Inpage', err) ) pump( mux, pluginStream, mux, (err) => logStreamDisconnectWarning('MetaMask Background', err) ) // connect ping stream const pongStream = new PongStream({ objectMode: true }) pump( mux, pongStream, mux, (err) => logStreamDisconnectWarning('MetaMask PingPongStream', err) ) // connect phishing warning stream const phishingStream = mux.createStream('phishing') phishingStream.once('data', redirectToPhishingWarning) // ignore unused channels (handled by background, inpage) mux.ignoreStream('provider') mux.ignoreStream('publicConfig') } /** * Establishes listeners for requests to fully-enable the provider from the dapp context * and for full-provider approvals and rejections from the background script context. Dapps * should not post messages directly and should instead call provider.enable(), which * handles posting these messages internally. */ function listenForProviderRequest () { window.addEventListener('message', ({ source, data }) => { if (source !== window || !data || !data.type) { return } switch (data.type) { case 'ETHEREUM_ENABLE_PROVIDER': extension.runtime.sendMessage({ action: 'init-provider-request', origin: source.location.hostname, siteImage: getSiteIcon(source), siteTitle: getSiteName(source), }) break case 'ETHEREUM_IS_APPROVED': extension.runtime.sendMessage({ action: 'init-is-approved', origin: source.location.hostname, }) break case 'METAMASK_IS_UNLOCKED': extension.runtime.sendMessage({ action: 'init-is-unlocked', }) break } }) extension.runtime.onMessage.addListener(({ action = '', isApproved, caching, isUnlocked }) => { switch (action) { case 'approve-provider-request': isEnabled = true injectScript(`window.dispatchEvent(new CustomEvent('ethereumprovider', { detail: {}}))`) break case 'reject-provider-request': injectScript(`window.dispatchEvent(new CustomEvent('ethereumprovider', { detail: { error: 'User rejected provider access' }}))`) break case 'answer-is-approved': injectScript(`window.dispatchEvent(new CustomEvent('ethereumisapproved', { detail: { isApproved: ${isApproved}, caching: ${caching}}}))`) break case 'answer-is-unlocked': injectScript(`window.dispatchEvent(new CustomEvent('metamaskisunlocked', { detail: { isUnlocked: ${isUnlocked}}}))`) break case 'metamask-set-locked': isEnabled = false injectScript(`window.dispatchEvent(new CustomEvent('metamasksetlocked', { detail: {}}))`) break } }) } /** * Checks if MetaMask is currently operating in "privacy mode", meaning * dapps must call ethereum.enable in order to access user accounts */ function checkPrivacyMode () { extension.runtime.sendMessage({ action: 'init-privacy-request' }) } /** * Error handler for page to plugin 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$/, ] const currentUrl = window.location.pathname for (let i = 0; i < prohibitedTypes.length; i++) { if (prohibitedTypes[i].test(currentUrl)) { return false } } return true } /** * Checks the documentElement of the current document * * @returns {boolean} {@code true} if the documentElement is an html node or if none exists */ function documentElementCheck () { var documentElement = document.documentElement.nodeName if (documentElement) { return documentElement.toLowerCase() === 'html' } return true } /** * Checks if the current domain is blacklisted * * @returns {boolean} {@code true} if the current domain is blacklisted */ function blacklistedDomainCheck () { var blacklistedDomains = [ 'uscourts.gov', 'dropbox.com', 'webbyawards.com', 'cdn.shopify.com/s/javascripts/tricorder/xtld-read-only-frame.html', 'adyen.com', 'gravityforms.com', 'harbourair.com', 'ani.gamer.com.tw', 'blueskybooking.com', ] var currentUrl = window.location.href var currentRegex for (let i = 0; i < blacklistedDomains.length; i++) { const blacklistedDomain = blacklistedDomains[i].replace('.', '\\.') currentRegex = new RegExp(`(?:https?:\\/\\/)(?:(?!${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, })}` } function getSiteName (window) { const document = window.document const siteName = document.querySelector('head > meta[property="og:site_name"]') if (siteName) { return siteName.content } return document.title } 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 }