Protect crypto initialization checks

gumble/gumble/crypt.go

@@ -270,6 +270,12 @@ func (cs *cryptState) nonceForPacket(counter uint32) [12]byte {
 	return n
 }
 
+func (cs *cryptState) isInitialized() bool {
+	cs.mu.Lock()
+	defer cs.mu.Unlock()
+	return cs.initialized
+}
+
 func (cs *cryptState) encrypt(counter uint32, plaintext []byte) ([]byte, error) {
 	cs.mu.Lock()
 	defer cs.mu.Unlock()
@@ -301,7 +307,7 @@ func (c *Client) handleCryptSetup(buffer []byte) error {
 	defer c.volatile.Unlock()
 
 	if packet.Key != nil && packet.ClientNonce != nil && packet.ServerNonce != nil {
-		wasInit := c.cryptOut.initialized
+		wasInit := c.cryptOut.isInitialized()
 		c.cryptOut.setup(packet.Key, packet.ClientNonce)
 		c.cryptIn.setup(packet.Key, packet.ServerNonce)
 
@@ -316,14 +322,15 @@ func (c *Client) handleCryptSetup(buffer []byte) error {
 			log.Info("received CryptSetup: key_len=%d client_nonce_len=%d server_nonce_len=%d",
 				len(packet.Key), len(packet.ClientNonce), len(packet.ServerNonce))
 		}
-	} else if !c.cryptOut.initialized {
+	} else if !c.cryptOut.isInitialized() {
 		// Only log incomplete once before crypto is set up
 		log.Debug("received CryptSetup with incomplete fields, waiting for full key exchange")
 	}
 
+	cryptoReady := c.cryptOut.isInitialized()
 	c.udpMu.Lock()
 	udpReady := c.udpCryptoOut != nil
-	startUDP := c.cryptOut.initialized && c.udpConn != nil && !c.udpStarted && udpReady
+	startUDP := cryptoReady && c.udpConn != nil && !c.udpStarted && udpReady
 	if startUDP {
 		// Keep TCP tunnelling enabled until an authenticated UDP packet proves
 		// that the inbound path works.
@@ -335,7 +342,7 @@ func (c *Client) handleCryptSetup(buffer []byte) error {
 		log.Info("UDP crypto ready (1.5 native), starting UDP reader and pinger")
 		go c.udpReadRoutine()
 		go c.udpPingRoutine()
-	} else if c.cryptOut.initialized && noUDPConn {
+	} else if cryptoReady && noUDPConn {
 		log.Warn("crypto ready but no UDP socket — audio will use TCP tunnel")
 	}