security(csp): tighten font-src and style-src now that fonts are self-hosted

src/__tests__/csp-headers.test.ts

@@ -0,0 +1,65 @@
+import { describe, it, expect } from "vitest";
+import request from "supertest";
+import { app } from "../index.js";
+
+/**
+ * Content-Security-Policy headers should be as tight as possible.
+ *
+ * Since self-hosting Inter (GDPR fix), there is no need to allow
+ *   font-src 'self' https: data:
+ *   style-src 'self' https: 'unsafe-inline'
+ * on either the default (helmet) CSP or the /docs custom CSP.
+ *
+ * - font-src should be "'self'" only
+ * - style-src should allow 'self' and 'unsafe-inline' (inline style="..." in HTML),
+ *   but NOT https:
+ * - /docs must still allow 'unsafe-eval' in script-src for Swagger UI
+ */
+describe("Content-Security-Policy headers", () => {
+  describe("default CSP (helmet) on landing page", () => {
+    it("font-src is 'self' only (no https:, no data:)", async () => {
+      const res = await request(app).get("/");
+      const csp = res.headers["content-security-policy"];
+      expect(csp, "content-security-policy header missing").toBeDefined();
+      expect(csp).toMatch(/font-src\s+'self'(?:\s*;|\s*$)/);
+      expect(csp).not.toMatch(/font-src[^;]*https:/);
+      expect(csp).not.toMatch(/font-src[^;]*\bdata:/);
+    });
+
+    it("style-src contains 'self' and 'unsafe-inline' but no https:", async () => {
+      const res = await request(app).get("/");
+      const csp = res.headers["content-security-policy"];
+      expect(csp).toBeDefined();
+      expect(csp).toMatch(/style-src[^;]*'self'/);
+      expect(csp).toMatch(/style-src[^;]*'unsafe-inline'/);
+      expect(csp).not.toMatch(/style-src[^;]*https:/);
+    });
+  });
+
+  describe("custom CSP on /docs (Swagger UI)", () => {
+    it("font-src is 'self' only", async () => {
+      const res = await request(app).get("/docs");
+      const csp = res.headers["content-security-policy"];
+      expect(csp, "content-security-policy header missing on /docs").toBeDefined();
+      expect(csp).toMatch(/font-src\s+'self'(?:\s*;|\s*$)/);
+      expect(csp).not.toMatch(/font-src[^;]*https:/);
+      expect(csp).not.toMatch(/font-src[^;]*\bdata:/);
+    });
+
+    it("style-src contains 'self' and 'unsafe-inline' but no https:", async () => {
+      const res = await request(app).get("/docs");
+      const csp = res.headers["content-security-policy"];
+      expect(csp).toBeDefined();
+      expect(csp).toMatch(/style-src[^;]*'self'/);
+      expect(csp).toMatch(/style-src[^;]*'unsafe-inline'/);
+      expect(csp).not.toMatch(/style-src[^;]*https:/);
+    });
+
+    it("script-src still contains 'unsafe-eval' (required by Swagger UI)", async () => {
+      const res = await request(app).get("/docs");
+      const csp = res.headers["content-security-policy"];
+      expect(csp).toBeDefined();
+      expect(csp).toMatch(/script-src[^;]*'unsafe-eval'/);
+    });
+  });
+});

src/index.ts

@@ -30,7 +30,21 @@ import { startPeriodicCleanup, stopPeriodicCleanup } from "./utils/periodic-clea
 const app = express();
 const PORT = parseInt(process.env.PORT || "3100", 10);
 
-app.use(helmet({ crossOriginResourcePolicy: { policy: "cross-origin" } }));
+// Content-Security-Policy: tightened now that Inter font is self-hosted.
+// - font-src: 'self' only (no external CDNs, no data: URIs)
+// - style-src: 'self' + 'unsafe-inline' (codebase uses inline style="..." attributes)
+// - script-src: 'self' (default; /docs overrides to add 'unsafe-eval' for Swagger UI)
+app.use(
+  helmet({
+    contentSecurityPolicy: {
+      directives: {
+        "font-src": ["'self'"],
+        "style-src": ["'self'", "'unsafe-inline'"],
+      },
+    },
+    crossOriginResourcePolicy: { policy: "cross-origin" },
+  })
+);
 
 // Request ID + request logging middleware
 app.use((req, res, next) => {

src/routes/pages.ts

@@ -28,7 +28,7 @@ pagesRouter.get("/openapi.json", (_req: Request, res: Response) => {
 pagesRouter.get("/docs", (_req: Request, res: Response) => {
   res.setHeader(
     "Content-Security-Policy",
-    "default-src 'self';script-src 'self' 'unsafe-eval';style-src 'self' https: 'unsafe-inline';img-src 'self' data: blob:;font-src 'self' https: data:;connect-src 'self';worker-src 'self' blob:;base-uri 'self';form-action 'self';frame-ancestors 'self';object-src 'none'"
+    "default-src 'self';script-src 'self' 'unsafe-eval';style-src 'self' 'unsafe-inline';img-src 'self' data: blob:;font-src 'self';connect-src 'self';worker-src 'self' blob:;base-uri 'self';form-action 'self';frame-ancestors 'self';object-src 'none'"
   );
   res.setHeader("Cache-Control", "public, max-age=86400");
   res.sendFile(path.join(publicDir, "docs.html"));