WeCenter SQL注射（ROOT SHELL）

public function question_list_action()  {   if ($_GET['feature_id'])   {    if ($topic_ids = $this->model('feature')->get_topics_by_feature_id($_GET['feature_id']))    {     $_GET['topic_id'] = implode(',', $topic_ids);    }   }    switch ($_GET['type'])   {    case 'best':     $action_list = $this->model('topic')->get_topic_best_answer_action_list($_GET['topic_id'], $this->user_id, intval($_GET['page']) * get_setting('contents_per_page') . ', ' . get_setting('contents_per_page'))           topic.php： public function get_topic_best_answer_action_list($topic_ids, $uid, $limit)  {   $cache_key = 'topic_best_answer_action_list_' . md5($topic_ids . $limit);    if (!$result = AWS_APP::cache()->get($cache_key))   {    echo " WHERE topic_id IN (" . implode(',', explode(',', $topic_ids)) . ") AND `type` = 'question'";    if ($topic_relation = $this->query_all("SELECT item_id FROM " . $this->get_table('topic_relation') . " WHERE topic_id IN (" . implode(',', explode(',', $topic_ids)) . ") AND `type` = 'question'"))