      function onError(err) {
        if (this === client) {
          assert(!cliError, msg('Unexpected multiple client errors'));
          cliError = err;
        } else {
          assert(!srvError, msg('Unexpected multiple server errors'));
          srvError = err;
        }
        assert.strictEqual(err.level, 'handshake');
        assert(/handshake failed/i.test(err.message),
               msg('Wrong error message'));
      }
The software constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.