import crypto from "crypto"; import type { IncomingMessage, OutgoingMessage } from "http"; import { z } from "zod"; import { IS_PRODUCTION } from "@calcom/lib/constants"; import { WEBAPP_URL } from "@calcom/lib/constants"; function getCspPolicy(nonce: string) { //TODO: Do we need to explicitly define it in turbo.json const CSP_POLICY = process.env.CSP_POLICY; // Note: "non-strict" policy only allows inline styles otherwise it's the same as "strict" // We can remove 'unsafe-inline' from style-src when we add nonces to all style tags // Maybe see how @next-safe/middleware does it if it's supported. const useNonStrictPolicy = CSP_POLICY === "non-strict"; // We add WEBAPP_URL to img-src because of booking pages, which end up loading images from app.cal.com on cal.com // FIXME: Write a layer to extract out EventType Analytics tracking endpoints and add them to img-src or connect-src as needed. e.g. fathom, Google Analytics and others return ` default-src 'self' ${IS_PRODUCTION ? "" : "data:"}; script-src ${ IS_PRODUCTION ? // 'self' 'unsafe-inline' https: added for Browsers not supporting strict-dynamic not supporting strict-dynamic "'nonce-" + nonce + "' 'strict-dynamic' 'self' 'unsafe-inline' https:" : // Note: We could use 'strict-dynamic' with 'nonce-..' instead of unsafe-inline but there are some streaming related scripts that get blocked(because they don't have nonce on them). It causes a really frustrating full page error model by Next.js to show up sometimes "'unsafe-inline' 'unsafe-eval' https: http:" }; object-src 'none'; base-uri 'none'; child-src app.cal.com; style-src 'self' ${ IS_PRODUCTION ? (useNonStrictPolicy ? "'unsafe-inline'" : "") : "'unsafe-inline'" } app.cal.com; font-src 'self'; img-src 'self' ${WEBAPP_URL} https://img.youtube.com https://eu.ui-avatars.com/api/ data:; connect-src 'self' `; } // Taken from @next-safe/middleware const isPagePathRequest = (url: URL) => { const isNonPagePathPrefix = /^\/(?:_next|api)\//; const isFile = /\..*$/; const { pathname } = url; return !isNonPagePathPrefix.test(pathname) && !isFile.test(pathname); }; export function csp(req: IncomingMessage | null, res: OutgoingMessage | null) { if (!req) { return { nonce: undefined }; } const existingNonce = req.headers["x-nonce"]; if (existingNonce) { const existingNoneParsed = z.string().safeParse(existingNonce); return { nonce: existingNoneParsed.success ? existingNoneParsed.data : "" }; } if (!req.url) { return { nonce: undefined }; } const CSP_POLICY = process.env.CSP_POLICY; const cspEnabledForInstance = CSP_POLICY; const nonce = crypto.randomBytes(16).toString("base64"); const parsedUrl = new URL(req.url, "http://base_url"); const cspEnabledForPage = cspEnabledForInstance && isPagePathRequest(parsedUrl); if (!cspEnabledForPage) { return { nonce: undefined, }; } // Set x-nonce request header to be used by `getServerSideProps` or similar fns and `Document.getInitialProps` to read the nonce from // It is generated for all page requests but only used by pages that need CSP req.headers["x-nonce"] = nonce; if (res) { res.setHeader( req.headers["x-csp-enforce"] === "true" ? "Content-Security-Policy" : "Content-Security-Policy-Report-Only", getCspPolicy(nonce) .replace(/\s{2,}/g, " ") .trim() ); } return { nonce }; }