Crypto in vc

src/vc_server.rs

@@ -2,9 +2,9 @@ use std::{net::SocketAddr, sync::Arc};
 
 use anyhow::Context;
 use ed25519_dalek::VerifyingKey;
-use tokio::net::UdpSocket;
+use tokio::{net::UdpSocket, sync::Mutex};
 
-use crate::{protocol::ClientMethod, server::Server};
+use crate::{crypto::SessionCipher, protocol::ClientMethod, server::Server};
 
 use tokio::time::Instant;
 
@@ -31,16 +31,18 @@ impl Server {
             let pin_bytes: [u8; 8] = buf[..8].try_into().unwrap();
             let pin = u64::from_be_bytes(pin_bytes);
 
-            let (sender_pubkey, channel_id, payload) = {
+            // is_first_packet distinguishes the plaintext pin-bootstrap packet
+            // from subsequent encrypted audio packets.
+            let (sender_pubkey, channel_id, payload, is_first_packet) = {
                 let mut pins = self.voice_pins.lock().await;
 
                 if let Some((pubkey, channel_id)) = pins.remove(&pin) {
-                    (pubkey, channel_id, &buf[8..len])
+                    (pubkey, channel_id, &buf[8..len], true)
                 } else {
                     drop(pins);
 
                     match self.find_voice_sender(&addr).await {
-                        Some((pubkey, channel_id)) => (pubkey, channel_id, &buf[..]),
+                        Some((pubkey, channel_id)) => (pubkey, channel_id, &buf[..len], false),
                         None => {
                             continue;
                         }
@@ -69,8 +71,31 @@ impl Server {
 
             drop(voice);
 
-            self.relay_voice(&sender_pubkey, &channel_id, payload)
+            // The pin-bearing bootstrap packet carries no payload to decrypt —
-                .await?;
+            // it's purely "here's my pin, bind my address." Everything after
+            // this first packet is the real, encrypted audio stream.
+            if is_first_packet {
+                continue;
+            }
+
+            let decrypted_payload = match user.cihper.lock().await.decrypt(payload) {
+                Ok(pt) => pt,
+                Err(e) => {
+                    eprintln!("[vc] dropping packet: decryption failed: {e}");
+                    continue;
+                }
+            };
+
+            let s = self.clone();
+
+            tokio::spawn(async move {
+                if let Err(e) = s
+                    .relay_voice(&sender_pubkey, &channel_id, &decrypted_payload)
+                    .await
+                {
+                    eprintln!("{e}");
+                }
+            });
         }
     }
 
@@ -125,7 +150,7 @@ impl Server {
                 continue;
             }
 
-            let _ = self.udp_send_to(&voice.addr, payload).await;
+            let _ = self.udp_send_to(&user.cihper, &voice.addr, payload).await;
         }
 
         Ok(())
@@ -137,10 +162,17 @@ impl Server {
             .context("Failed to get voice socket")
     }
 
-    pub async fn udp_send_to(&self, addr: &SocketAddr, payload: &[u8]) -> anyhow::Result<()> {
+    pub async fn udp_send_to(
+        &self,
+        cipher: &Arc<Mutex<SessionCipher>>,
+        addr: &SocketAddr,
+        payload: &[u8],
+    ) -> anyhow::Result<()> {
         let socket = self.get_voice_socket()?;
 
-        socket.send_to(payload, addr).await?;
+        socket
+            .send_to(&cipher.lock().await.encrypt(payload)?, addr)
+            .await?;
 
         Ok(())
     }