fix: critical security issues - webhook bypass, SSRF, XSS

src/routes/billing.ts

@@ -2,6 +2,10 @@ import { Router, Request, Response } from "express";
 import Stripe from "stripe";
 import { createProKey, revokeByCustomer } from "../services/keys.js";
 
+function escapeHtml(s: string): string {
+  return s.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;").replace(/"/g, "&quot;").replace(/'/g, "&#39;");
+}
+
 let _stripe: Stripe | null = null;
 function getStripe(): Stripe {
   if (!_stripe) {
@@ -69,7 +73,7 @@ a { color: #4f9; }
 <div class="card">
 <h1>🎉 Welcome to Pro!</h1>
 <p>Your API key:</p>
-<div class="key" onclick="navigator.clipboard.writeText('${keyInfo.key}')" title="Click to copy">${keyInfo.key}</div>
+<div class="key" onclick="navigator.clipboard.writeText('${escapeHtml(keyInfo.key)}')" title="Click to copy">${escapeHtml(keyInfo.key)}</div>
 <p><strong>Save this key!</strong> It won't be shown again.</p>
 <p>10,000 PDFs/month • All endpoints • Priority support</p>
 <p><a href="/docs">View API docs →</a></p>
@@ -87,16 +91,17 @@ router.post("/webhook", async (req: Request, res: Response) => {
 
   let event: Stripe.Event;
 
-  if (webhookSecret && sig) {
+  if (!webhookSecret || !sig) {
-    try {
+    res.status(400).json({ error: "Missing webhook secret or signature" });
-      event = getStripe().webhooks.constructEvent(req.body, sig, webhookSecret);
+    return;
-    } catch (err: any) {
+  }
-      console.error("Webhook signature verification failed:", err.message);
+
-      res.status(400).json({ error: "Invalid signature" });
+  try {
-      return;
+    event = getStripe().webhooks.constructEvent(req.body, sig, webhookSecret);
-    }
+  } catch (err: any) {
-  } else {
+    console.error("Webhook signature verification failed:", err.message);
-    event = req.body as Stripe.Event;
+    res.status(400).json({ error: "Invalid signature" });
+    return;
   }
 
   switch (event.type) {

src/routes/convert.ts

@@ -1,6 +1,24 @@
 import { Router, Request, Response } from "express";
 import { renderPdf, renderUrlPdf } from "../services/browser.js";
 import { markdownToHtml, wrapHtml } from "../services/markdown.js";
+import dns from "node:dns/promises";
+import net from "node:net";
+
+function isPrivateIP(ip: string): boolean {
+  // IPv6 loopback/unspecified
+  if (ip === "::1" || ip === "::") return true;
+  // IPv4-mapped IPv6
+  if (ip.startsWith("::ffff:")) ip = ip.slice(7);
+  if (!net.isIPv4(ip)) return false;
+  const parts = ip.split(".").map(Number);
+  if (parts[0] === 0) return true;                           // 0.0.0.0/8
+  if (parts[0] === 10) return true;                           // 10.0.0.0/8
+  if (parts[0] === 127) return true;                          // 127.0.0.0/8
+  if (parts[0] === 169 && parts[1] === 254) return true;     // 169.254.0.0/16
+  if (parts[0] === 172 && parts[1] >= 16 && parts[1] <= 31) return true; // 172.16.0.0/12
+  if (parts[0] === 192 && parts[1] === 168) return true;     // 192.168.0.0/16
+  return false;
+}
 
 export const convertRouter = Router();
 
@@ -93,9 +111,10 @@ convertRouter.post("/url", async (req: Request, res: Response) => {
       return;
     }
 
-    // Basic URL validation
+    // URL validation + SSRF protection
+    let parsed: URL;
     try {
-      const parsed = new URL(body.url);
+      parsed = new URL(body.url);
       if (!["http:", "https:"].includes(parsed.protocol)) {
         res.status(400).json({ error: "Only http/https URLs are supported" });
         return;
@@ -105,6 +124,18 @@ convertRouter.post("/url", async (req: Request, res: Response) => {
       return;
     }
 
+    // DNS lookup to block private/reserved IPs
+    try {
+      const { address } = await dns.lookup(parsed.hostname);
+      if (isPrivateIP(address)) {
+        res.status(400).json({ error: "URL resolves to private/reserved IP" });
+        return;
+      }
+    } catch {
+      res.status(400).json({ error: "DNS lookup failed for URL hostname" });
+      return;
+    }
+
     const pdf = await renderUrlPdf(body.url, {
       format: body.format,
       landscape: body.landscape,