write back error status when authentication timeout

proxy/socks/protocol.go

@@ -105,10 +105,7 @@ func (s *ServerSession) Handshake(reader io.Reader, writer io.Writer) (*protocol
 
 		if expectedAuth == authPassword {
 			username, password, err := readUsernamePassword(reader)
-			if err != nil {
-				return nil, errors.Base(err).Message("Socks|Server: Failed to read username or password.")
-			}
-			if !s.config.HasAccount(username, password) {
+			if err != nil || !s.config.HasAccount(username, password) {
 				writeSocks5AuthenticationResponse(writer, 0xFF)
 				return nil, errors.Base(err).Message("Socks|Server: Invalid username or password.")
 			}