【用户验证】这样的思路验证用户是否登录的有没有漏洞、有关问题

/**
 * 初始化，用户COOKIE数据验证 by default7#zbphp.com
 */
public function authCheck()
{
    if (cookie('uid')) {
        $uid = cookie('uid');
        $umd5 = cookie('umd5');
        $udata = cookie('udata');
        if (isUid($uid) && isMd5($umd5) && $udata && ($strDecode = authcode($udata, 'DECODE'))
            && md5($strDecode) == $umd5 && ($data = json_decode($strDecode)) && $data['uid'] == $uid) {

            //每隔60s必须查询SQL检测一次
            if ($this->time - $data['lastactive'] > self::INTERVAL) {
                if (($rsUser = M('Member')->where("mid='$uid'")->getField('mid,uname,pwd,vip,viptime1,viptime2,lastactive,isfbd'))
                    && strtolower($rsUser['uname']) == strtolower($data['uname'])
                    && strtolower($rsUser['email']) == strtolower($data['email'])
                    && md5($rsUser['pwd'].$data['salt']) == $data['upwd']
                ) {

                    if($rsUser['isfbd'] == 't'){
                        $this->error('您的账号已被封禁，请联系管理员！');
                        $this->resetUser();
                        return;
                    }

                    //更新最后在线时间
                    M('Member')->setField('lastactive',$this->time);

                    //重新生成加密密匙
                    $data['salt'] = uniqid();
                    $data['upwd'] = md5($rsUser['pwd'].$data['salt']);

                }else{

                    $this->error('账号信息(邮箱或密码)发生变化，请重新登录！','',U('Member/Index/login?f='.__URL__));
                    $this->resetUser();
                    return;

                }
            }

            $data['lastactive'] = $this->time;

            $this->UserData = $data;

            $strEncode = json_encode($data);

            //配置COOKIE默认10天过期
            cookie('uid',$data['uid']);
            cookie('umd5',md5($strEncode));
            cookie('udata',authcode($strEncode,'ENCODE'));

            return;
        }

        $this->resetUser();
    }
}

/**
 * 注销SESSION 所有
 *
 * @return bool
 */
public function resetUser()