Security fixes: swarm signature verification and error handling

src/app/api/swarm/announce/route.ts

@@ -2,12 +2,15 @@
  * Swarm Announce Endpoint
  * 
  * POST: Receive announcements from other nodes joining the swarm
+ * 
+ * SECURITY: All requests must be cryptographically signed by the sender node.
  */
 
 import { NextResponse } from 'next/server';
 import { z } from 'zod';
 import { upsertSwarmNode } from '@/lib/swarm/registry';
 import { buildAnnouncement } from '@/lib/swarm/discovery';
+import { verifySwarmRequest } from '@/lib/swarm/signature';
 import type { SwarmNodeInfo } from '@/lib/swarm/types';
 
 const announcementSchema = z.object({
@@ -21,7 +24,11 @@ const announcementSchema = z.object({
   postCount: z.number().optional(),
   capabilities: z.array(z.enum(['handles', 'gossip', 'relay', 'search', 'interactions'])).optional(),
   timestamp: z.string().optional(),
-  signature: z.string().optional(),
+});
+
+// Schema including signature for verification
+const signedAnnouncementSchema = announcementSchema.extend({
+  signature: z.string(),
 });
 
 /**
@@ -29,39 +36,53 @@ const announcementSchema = z.object({
  * 
  * Receives an announcement from another node and responds with our info.
  * This is how nodes introduce themselves to the swarm.
+ * 
+ * SECURITY: All announcement requests must be signed by the sender node.
  */
 export async function POST(request: Request) {
   try {
     const body = await request.json();
-    const announcement = announcementSchema.parse(body);
+    const data = signedAnnouncementSchema.parse(body);
     
     const ourDomain = process.env.NEXT_PUBLIC_NODE_DOMAIN;
     
     // Don't process announcements from ourselves
-    if (announcement.domain === ourDomain) {
+    if (data.domain === ourDomain) {
       return NextResponse.json(
         { error: 'Cannot announce to self' },
         { status: 400 }
       );
     }
 
+    // SECURITY: Verify the node signature before processing
+    const { signature, ...payload } = data;
+    const isValid = await verifySwarmRequest(payload, signature, data.domain);
+
+    if (!isValid) {
+      console.warn(`[Swarm] Invalid signature for announcement from ${data.domain}`);
+      return NextResponse.json(
+        { error: 'Invalid signature' },
+        { status: 403 }
+      );
+    }
+
     // Add/update the announcing node in our registry
     const nodeInfo: SwarmNodeInfo = {
-      domain: announcement.domain,
-      name: announcement.name,
-      description: announcement.description,
-      logoUrl: announcement.logoUrl,
-      publicKey: announcement.publicKey,
-      softwareVersion: announcement.softwareVersion,
-      userCount: announcement.userCount,
-      postCount: announcement.postCount,
-      capabilities: announcement.capabilities,
+      domain: data.domain,
+      name: data.name,
+      description: data.description,
+      logoUrl: data.logoUrl,
+      publicKey: data.publicKey,
+      softwareVersion: data.softwareVersion,
+      userCount: data.userCount,
+      postCount: data.postCount,
+      capabilities: data.capabilities,
       lastSeenAt: new Date().toISOString(),
     };
 
     const { isNew } = await upsertSwarmNode(nodeInfo, 'announcement');
 
-    console.log(`[Swarm] ${isNew ? 'New' : 'Known'} node announced: ${announcement.domain}`);
+    console.log(`[Swarm] ${isNew ? 'New' : 'Known'} node announced: ${data.domain}`);
 
     // Respond with our own info
     const ourAnnouncement = await buildAnnouncement();