Import source: app/backend/src/plugins/security-headers

Import the existing local project snapshot. This commit organizes existing files; it does not represent newly developed functionality.

app/backend/src/plugins/security-headers.ts

@@ -0,0 +1,36 @@
+import fp from 'fastify-plugin';
+import type { FastifyInstance, FastifyRequest, FastifyReply } from 'fastify';
+import { randomBytes } from 'node:crypto';
+
+declare module 'fastify' {
+  interface FastifyReply {
+    cspNonce: string;
+  }
+}
+
+function generateNonce(): string {
+  return randomBytes(16).toString('base64');
+}
+
+export default fp(async function securityHeadersPlugin(app: FastifyInstance) {
+  app.decorateReply('cspNonce', '');
+
+  app.addHook('onRequest', async (req: FastifyRequest, reply: FastifyReply) => {
+    const nonce = generateNonce();
+    reply.cspNonce = nonce;
+    reply.header('X-Content-Type-Options', 'nosniff');
+    reply.header('X-Frame-Options', 'SAMEORIGIN');
+    reply.header('Referrer-Policy', 'strict-origin-when-cross-origin');
+    reply.header('Permissions-Policy', 'camera=(), microphone=(), geolocation=()');
+
+    if (req.url.startsWith('/embed') || req.url === '/embed.html') {
+      reply.header('Content-Security-Policy', `default-src 'self'; script-src 'self' 'nonce-${nonce}'; style-src 'self' 'unsafe-inline'; frame-ancestors *; report-uri /api/v1/csp-report`);
+    } else {
+      reply.header('Content-Security-Policy', `default-src 'self'; script-src 'self' 'nonce-${nonce}'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob:; font-src 'self'; connect-src 'self'; frame-ancestors 'self'; form-action 'self'; report-uri /api/v1/csp-report`);
+    }
+
+    if (process.env.NODE_ENV === 'production') {
+      reply.header('Strict-Transport-Security', 'max-age=31536000; includeSubDomains');
+    }
+  });
+});