network-libp2p: Verify also peer contacts received

Add verification of peer contacts received from the different
messages that can transmit a list of peer contacts in the discovery
protocol. The verification includes checks for appropriate lengths,
signatures and number of addresses.

network-libp2p/src/discovery/handler.rs

@@ -528,6 +528,32 @@ impl ConnectionHandler for Handler {
                                         );
                                     }
 
+                                    // Check and verify the peer contacts received
+                                    if peer_contacts.len() > self.config.update_limit as usize {
+                                        return Poll::Ready(
+                                            ConnectionHandlerEvent::NotifyBehaviour(
+                                                HandlerOutEvent::Error(
+                                                    Error::UpdateLimitExceeded {
+                                                        num_peer_contacts: peer_contacts.len(),
+                                                    },
+                                                ),
+                                            ),
+                                        );
+                                    }
+                                    for peer_contact in &peer_contacts {
+                                        if !peer_contact.verify() {
+                                            return Poll::Ready(
+                                                ConnectionHandlerEvent::NotifyBehaviour(
+                                                    HandlerOutEvent::Error(
+                                                        Error::InvalidPeerContactSignature {
+                                                            peer_contact: peer_contact.clone(),
+                                                        },
+                                                    ),
+                                                ),
+                                            );
+                                        }
+                                    }
+
                                     let mut peer_contact_book = self.peer_contact_book.write();
 
                                     // Insert the peer into the peer contact book.
@@ -614,7 +640,7 @@ impl ConnectionHandler for Handler {
                                     }
                                     self.last_update_time = Some(now);
 
-                                    // Check if the update is not too large.
+                                    // Check if the update is not too large and if the peer contacts verify
                                     if peer_contacts.len() > self.config.update_limit as usize {
                                         return Poll::Ready(
                                             ConnectionHandlerEvent::NotifyBehaviour(
@@ -626,6 +652,19 @@ impl ConnectionHandler for Handler {
                                             ),
                                         );
                                     }
+                                    for peer_contact in &peer_contacts {
+                                        if !peer_contact.verify() {
+                                            return Poll::Ready(
+                                                ConnectionHandlerEvent::NotifyBehaviour(
+                                                    HandlerOutEvent::Error(
+                                                        Error::InvalidPeerContactSignature {
+                                                            peer_contact: peer_contact.clone(),
+                                                        },
+                                                    ),
+                                                ),
+                                            );
+                                        }
+                                    }
 
                                     // Insert the new peer contacts into the peer contact book.
                                     self.peer_contact_book.write().insert_all_filtered(

network-libp2p/tests/network.rs

@@ -352,9 +352,9 @@ async fn create_network_with_n_peers(n_peers: usize) -> Vec<Network> {
     networks
 }
 
-#[test(tokio::test)]
+#[test(tokio::test(flavor = "multi_thread", worker_threads = 10))]
 async fn connections_stress_and_reconnect() {
-    let peers: usize = 15;
+    let peers: usize = 10;
     let networks = create_network_with_n_peers(peers).await;
 
     assert_eq!(peers, networks.len());