cal.pub0.org/apps/web/lib/csp.ts

84 lines
3.1 KiB
TypeScript

import crypto from "crypto";
import type { IncomingMessage, OutgoingMessage } from "http";
import { z } from "zod";
import { IS_PRODUCTION } 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";
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' ${
IS_PRODUCTION ? (useNonStrictPolicy ? "'unsafe-inline'" : "") : "'unsafe-inline'"
} app.cal.com;
font-src 'self';
img-src 'self' https://www.gravatar.com https://img.youtube.com https://eu.ui-avatars.com/api/ data:
`;
}
// Taken from @next-safe/middleware
const isPagePathRequest = (url: URL) => {
const isNonPagePathPrefix = /^\/(?:_next|api)\//;
const isFile = /\..*$/;
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 };
}