Program: CWE-79
Project: CVE-2022-0880
Buggy source:
<?php
namespace Api\Model;
use Api\Model\BaseModel;
use AsyncAws\S3\S3Client;

/**
 * 
 * @author star7th      
 */
class AttachmentModel extends BaseModel {

	Protected $autoCheckFields = false;  //一定要关闭字段缓存，不然会报找不到表的错误

	//获取某个用户的当前已使用附件流量
	public function getUserFlow($uid){
		$month = Date("Y-m") ;
		$file_flow = D("FileFlow")->where(" uid = '%s'  and date_month = '$month' " , array($uid))->find() ;
		if($file_flow){
			return intval($file_flow['used']) ;
		}else{
			D("FileFlow")->add(array(
				"uid" => $uid ,
				"used" => 0  ,
				"date_month" => $month ,

			));
			return 0 ;
		}
	}

	//记录某个用户流量
	public function recordUserFlow($uid , $file_size){
		$month = Date("Y-m") ;
		$used = $this->getUserFlow($uid) ;
		return D("FileFlow")->where(" uid = '%s'  and date_month = '$month' " , array($uid))->save(array(
			"used" => $used + intval($file_size) 
		));
	}

	public function deleteFile($file_id){
		$file_id = intval($file_id) ;
		$file = D("UploadFile")->where("file_id = '$file_id' ")->find();
		$real_url = $file['real_url'] ;
		$array = explode("/Public/Uploads/", $real_url) ;
		$file_path = "../Public/Uploads/".$array[1] ;
		if (file_exists($file_path)) {
			@unlink($file_path);
		}
		$this->deleteOss($real_url);
		D("UploadFile")->where(" file_id = '$file_id' ")->delete();
		D("FilePage")->where(" file_id = '$file_id' ")->delete();
		return true ;

	}

	//上传文件，返回url
	public function upload($_files , $file_key , $uid , $item_id = 0  , $page_id = 0  ){
		$uploadFile = $_files[$file_key] ;

		if($this->isDangerFilename($uploadFile['name'])){
			return false;
		}

		$oss_open = D("Options")->get("oss_open" ) ;
		if ($oss_open) {
				$url = $this->uploadOss($uploadFile);
				if ($url) {
						$sign = md5($url.time().rand()) ;
						$insert = array(
						"sign" => $sign,
						"uid" => $uid,
						"item_id" => $item_id,
						"page_id" => $page_id,
						"display_name" => $uploadFile['name'],
						"file_type" => $uploadFile['type'],
						"file_size" => $uploadFile['size'],
						"real_url" => $url,
						"addtime" => time(),
						);
						$file_id = D("UploadFile")->add($insert);
						$insert = array(
							"file_id" => $file_id,
							"item_id" => $item_id,
							"page_id" => $page_id,
							"addtime" => time(),
							);
						$ret = D("FilePage")->add($insert);
						$url = server_url("api/attachment/visitFile",array("sign" => $sign)); 
					  return $url ;
				}
		}else{
			$upload = new \Think\Upload();// 实例化上传类
			$upload->maxSize  = 1003145728 ;// 设置附件上传大小
			$upload->rootPath = './../Public/Uploads/';// 设置附件上传目录
			$upload->savePath = '';// 设置附件上传子目录
			$info = $upload->uploadOne($uploadFile) ;
			if(!$info) {// 上传错误提示错误信息
				var_dump($upload->getError());
				return;
			}else{// 上传成功 获取上传文件信息
				$url = site_url().'/Public/Uploads/'.$info['savepath'].$info['savename'] ;
				$sign = md5($url.time().rand()) ;
				$insert = array(
					"sign" => $sign,
					"uid" => $uid,
					"item_id" => $item_id,
					"page_id" => $page_id,
					"display_name" => $uploadFile['name'],
					"file_type" => $uploadFile['type'],
					"file_size" => $uploadFile['size'],
					"real_url" => $url,
					"addtime" => time(),
					);
					$file_id = D("UploadFile")->add($insert);
					$insert = array(
						"file_id" => $file_id,
						"item_id" => $item_id,
						"page_id" => $page_id,
						"addtime" => time(),
						);
					$ret = D("FilePage")->add($insert);
				$url = server_url("api/attachment/visitFile",array("sign" => $sign));
				return $url ;
			}
		}
		return false;
	}

  	//上传到oss。参数$uploadFile是文件上传流，如$_FILES['file'] .也可以自己拼凑
	public function uploadOss($uploadFile){
		$oss_setting_json = D("Options")->get("oss_setting") ;
		$oss_setting = json_decode($oss_setting_json,1);

		if ($oss_setting && $oss_setting['oss_type'] && ( $oss_setting['oss_type'] == 's3_storage' || $oss_setting['oss_type'] == 'aliyun') ) {

			return $this->uploadS3($uploadFile , $oss_setting);

		}

		if ($oss_setting && $oss_setting['oss_type'] && $oss_setting['oss_type'] == 'qiniu') {

			$oss_setting['endpoint'] = $this->getQiuniuEndpointByKey($oss_setting['key'] , $oss_setting['bucket']);
			return $this->uploadS3($uploadFile , $oss_setting); 

		}
		// 腾讯云
		if ($oss_setting && $oss_setting['oss_type'] && $oss_setting['oss_type'] == 'qcloud') {
			// 腾讯云，一开始让用户填写region而没填写endpoint，所以要自己拼接
			$oss_setting['endpoint'] = "https://cos.{$oss_setting['region']}.myqcloud.com";
			// 腾讯云的SecretId相当于s3的key， secretKey相当于s3的secret
			$oss_setting['key'] = $oss_setting['secretId']  ;
			$oss_setting['secret'] = $oss_setting['secretKey']  ;
			return $this->uploadS3($uploadFile , $oss_setting); 
		}


		return false ;
	}

	// 通过s3协议上传
	// 注意传进来的oss_setting数组需要先转换成合法格式
	public function uploadS3($uploadFile , $oss_setting){

		$ext = strrchr($uploadFile['name'], '.'); //获取扩展名
		$oss_path = "showdoc_".get_rand_str().$ext;

		// 如果不包含协议头，自己给它补充
		if(!strstr($oss_setting['endpoint'] , '://')){
			$oss_setting['endpoint'] = 'https://'.$oss_setting['endpoint'] ;
		}

		$s3 = new S3Client([
			'accessKeyId' => $oss_setting['key'],
			'accessKeySecret' => $oss_setting['secret'] ,
			'endpoint' => $oss_setting['endpoint'] ,
			'sendChunkedBody' => false
		]);
	
		// Send a PutObject request and get the result object.
		$resObj = $s3->putObject([
			'Bucket' => $oss_setting['bucket'],
			'Key'    => $oss_path,
			'Body'   => fopen($uploadFile['tmp_name'], 'rb')
		]);

		// 不抛出异常，默认就是成功的

		if ($oss_setting['domain']) {
			return $oss_setting['protocol'] . '://'.$oss_setting['domain']."/".$oss_path ;
		}else{
			$tmp_array = parse_url($oss_setting['endpoint']);
			$endpoint_host = $tmp_array['host'] ;
			return 'https://'.$oss_setting['bucket'].'.'.$endpoint_host.'/'.$oss_path;
		}
	}

  	//从oss中删除
	public function deleteOss($file_url){
		$oss_setting_json = D("Options")->get("oss_setting") ;
		$oss_setting = json_decode($oss_setting_json,1);
		if ($oss_setting && $oss_setting['oss_type'] && ( $oss_setting['oss_type'] == 's3_storage' || $oss_setting['oss_type'] == 'aliyun') ) {
			return $this->deleteS3($file_url , $oss_setting);
		}

		if ($oss_setting && $oss_setting['oss_type'] && $oss_setting['oss_type'] == 'qiniu') {
			$oss_setting['endpoint'] = $this->getQiuniuEndpointByKey($oss_setting['key'] , $oss_setting['bucket']);
			return $this->deleteS3($file_url , $oss_setting); 
		}
		//var_dump($config);
		// 腾讯云
		if ($oss_setting && $oss_setting['oss_type'] && $oss_setting['oss_type'] == 'qcloud') {

			// 腾讯云，一开始让用户填写region而没填写endpoint，所以要自己拼接
			$oss_setting['endpoint'] = "https://cos.{$oss_setting['region']}.myqcloud.com";
			// 腾讯云的SecretId相当于s3的key， secretKey相当于s3的secret
			$oss_setting['key'] = $oss_setting['secretId']  ;
			$oss_setting['secret'] = $oss_setting['secretKey']  ;
			return $this->deleteS3($file_url , $oss_setting); 

		}


		return false ;
	}

	// 通过s3协议删除
	// 注意传进来的oss_setting数组需要先转换成合法格式
	public function deleteS3($file_url , $oss_setting){

		$array = parse_url($file_url) ;
		$file = $array['path'] ;  // 得到的是url中的路径，例如/path_.txt
		$file = substr($file, 1); // 要把路径前的/去掉，才是得到文件名path_.txt
		// 如果不包含协议头，自己给它补充
		if(!strstr($oss_setting['endpoint'] , '://')){
			$oss_setting['endpoint'] = 'https://'.$oss_setting['endpoint'] ;
		}

		$s3 = new S3Client([
			'accessKeyId' => $oss_setting['key'],
			'accessKeySecret' => $oss_setting['secret'] ,
			'endpoint' => $oss_setting['endpoint'] ,
		]);
	
		// Send a PutObject request and get the result object.
		$resObj = $s3->deleteObject([
			'Bucket' => $oss_setting['bucket'],
			'Key'    => $file,
		]);

		// 不抛出异常，默认就是成功的


	}

	// 由于历史原因，当初没有让用户填写七牛云的region。而且即使填写了，也不能直接获取到七牛云s3兼容协议上传的endpoint
	// 所以，需要自己调接口查询然后拼凑。七牛这个坑货。
	public function getQiuniuEndpointByKey($key,$bucket){

		$query_url = "https://api.qiniu.com/v2/query?ak={$key}&bucket={$bucket}";
		$res = http_post($query_url,array());

		$array = json_decode($res,true) ;
		// var_dump($array);exit();
		if($array && $array['region'] ){
			switch ($array['region']) {
				case 'z0':
					return 'https://s3-cn-east-1.qiniucs.com';
					break;
				case 'z1':
					return 'https://s3-cn-north-1.qiniucs.com';
					break;
				case 'z2':
					return 'https://s3-cn-south-1.qiniucs.com';
					break;
				case 'na0':
					return 'https://s3-us-north-1.qiniucs.com';
					break;
				case 'as0':
					return 'https://s3-ap-southeast-1.qiniucs.com';
					break;
				default:
					return false;
					break;
			}

		}

	}

	// 判断文件名是否包含危险的扩展名
	public function isDangerFilename($filename){

		$isDangerStr = function ($filename , $keyword){
			if(strstr(strip_tags(strtolower( $filename )), $keyword) ){
				return true ;
			}
			return false;
		};
		if (
			 $isDangerStr($filename , ".php")
			|| $isDangerStr($filename , ".svg")
			|| $isDangerStr($filename , ".htm")
			|| $isDangerStr($filename , "%")
		) {
			return true;
		}
	
		return false;
	}



}

Fixed version (ground truth):
<?php
namespace Api\Model;
use Api\Model\BaseModel;
use AsyncAws\S3\S3Client;

/**
 * 
 * @author star7th      
 */
class AttachmentModel extends BaseModel {

	Protected $autoCheckFields = false;  //一定要关闭字段缓存，不然会报找不到表的错误

	//获取某个用户的当前已使用附件流量
	public function getUserFlow($uid){
		$month = Date("Y-m") ;
		$file_flow = D("FileFlow")->where(" uid = '%s'  and date_month = '$month' " , array($uid))->find() ;
		if($file_flow){
			return intval($file_flow['used']) ;
		}else{
			D("FileFlow")->add(array(
				"uid" => $uid ,
				"used" => 0  ,
				"date_month" => $month ,

			));
			return 0 ;
		}
	}

	//记录某个用户流量
	public function recordUserFlow($uid , $file_size){
		$month = Date("Y-m") ;
		$used = $this->getUserFlow($uid) ;
		return D("FileFlow")->where(" uid = '%s'  and date_month = '$month' " , array($uid))->save(array(
			"used" => $used + intval($file_size) 
		));
	}

	public function deleteFile($file_id){
		$file_id = intval($file_id) ;
		$file = D("UploadFile")->where("file_id = '$file_id' ")->find();
		$real_url = $file['real_url'] ;
		$array = explode("/Public/Uploads/", $real_url) ;
		$file_path = "../Public/Uploads/".$array[1] ;
		if (file_exists($file_path)) {
			@unlink($file_path);
		}
		$this->deleteOss($real_url);
		D("UploadFile")->where(" file_id = '$file_id' ")->delete();
		D("FilePage")->where(" file_id = '$file_id' ")->delete();
		return true ;

	}

	//上传文件，返回url
	public function upload($_files , $file_key , $uid , $item_id = 0  , $page_id = 0  ){
		$uploadFile = $_files[$file_key] ;

		if($this->isDangerFilename($uploadFile['name'])){
			return false;
		}

		$oss_open = D("Options")->get("oss_open" ) ;
		if ($oss_open) {
				$url = $this->uploadOss($uploadFile);
				if ($url) {
						$sign = md5($url.time().rand()) ;
						$insert = array(
						"sign" => $sign,
						"uid" => $uid,
						"item_id" => $item_id,
						"page_id" => $page_id,
						"display_name" => $uploadFile['name'],
						"file_type" => $uploadFile['type'],
						"file_size" => $uploadFile['size'],
						"real_url" => $url,
						"addtime" => time(),
						);
						$file_id = D("UploadFile")->add($insert);
						$insert = array(
							"file_id" => $file_id,
							"item_id" => $item_id,
							"page_id" => $page_id,
							"addtime" => time(),
							);
						$ret = D("FilePage")->add($insert);
						$url = server_url("api/attachment/visitFile",array("sign" => $sign)); 
					  return $url ;
				}
		}else{
			$upload = new \Think\Upload();// 实例化上传类
			$upload->maxSize  = 1003145728 ;// 设置附件上传大小
			$upload->rootPath = './../Public/Uploads/';// 设置附件上传目录
			$upload->savePath = '';// 设置附件上传子目录
			$info = $upload->uploadOne($uploadFile) ;
			if(!$info) {// 上传错误提示错误信息
				var_dump($upload->getError());
				return;
			}else{// 上传成功 获取上传文件信息
				$url = site_url().'/Public/Uploads/'.$info['savepath'].$info['savename'] ;
				$sign = md5($url.time().rand()) ;
				$insert = array(
					"sign" => $sign,
					"uid" => $uid,
					"item_id" => $item_id,
					"page_id" => $page_id,
					"display_name" => $uploadFile['name'],
					"file_type" => $uploadFile['type'],
					"file_size" => $uploadFile['size'],
					"real_url" => $url,
					"addtime" => time(),
					);
					$file_id = D("UploadFile")->add($insert);
					$insert = array(
						"file_id" => $file_id,
						"item_id" => $item_id,
						"page_id" => $page_id,
						"addtime" => time(),
						);
					$ret = D("FilePage")->add($insert);
				$url = server_url("api/attachment/visitFile",array("sign" => $sign));
				return $url ;
			}
		}
		return false;
	}

  	//上传到oss。参数$uploadFile是文件上传流，如$_FILES['file'] .也可以自己拼凑
	public function uploadOss($uploadFile){
		$oss_setting_json = D("Options")->get("oss_setting") ;
		$oss_setting = json_decode($oss_setting_json,1);

		if ($oss_setting && $oss_setting['oss_type'] && ( $oss_setting['oss_type'] == 's3_storage' || $oss_setting['oss_type'] == 'aliyun') ) {

			return $this->uploadS3($uploadFile , $oss_setting);

		}

		if ($oss_setting && $oss_setting['oss_type'] && $oss_setting['oss_type'] == 'qiniu') {

			$oss_setting['endpoint'] = $this->getQiuniuEndpointByKey($oss_setting['key'] , $oss_setting['bucket']);
			return $this->uploadS3($uploadFile , $oss_setting); 

		}
		// 腾讯云
		if ($oss_setting && $oss_setting['oss_type'] && $oss_setting['oss_type'] == 'qcloud') {
			// 腾讯云，一开始让用户填写region而没填写endpoint，所以要自己拼接
			$oss_setting['endpoint'] = "https://cos.{$oss_setting['region']}.myqcloud.com";
			// 腾讯云的SecretId相当于s3的key， secretKey相当于s3的secret
			$oss_setting['key'] = $oss_setting['secretId']  ;
			$oss_setting['secret'] = $oss_setting['secretKey']  ;
			return $this->uploadS3($uploadFile , $oss_setting); 
		}


		return false ;
	}

	// 通过s3协议上传
	// 注意传进来的oss_setting数组需要先转换成合法格式
	public function uploadS3($uploadFile , $oss_setting){

		$ext = strrchr($uploadFile['name'], '.'); //获取扩展名
		$oss_path = "showdoc_".get_rand_str().$ext;

		// 如果不包含协议头，自己给它补充
		if(!strstr($oss_setting['endpoint'] , '://')){
			$oss_setting['endpoint'] = 'https://'.$oss_setting['endpoint'] ;
		}

		$s3 = new S3Client([
			'accessKeyId' => $oss_setting['key'],
			'accessKeySecret' => $oss_setting['secret'] ,
			'endpoint' => $oss_setting['endpoint'] ,
			'sendChunkedBody' => false
		]);
	
		// Send a PutObject request and get the result object.
		$resObj = $s3->putObject([
			'Bucket' => $oss_setting['bucket'],
			'Key'    => $oss_path,
			'Body'   => fopen($uploadFile['tmp_name'], 'rb')
		]);

		// 不抛出异常，默认就是成功的

		if ($oss_setting['domain']) {
			return $oss_setting['protocol'] . '://'.$oss_setting['domain']."/".$oss_path ;
		}else{
			$tmp_array = parse_url($oss_setting['endpoint']);
			$endpoint_host = $tmp_array['host'] ;
			return 'https://'.$oss_setting['bucket'].'.'.$endpoint_host.'/'.$oss_path;
		}
	}

  	//从oss中删除
	public function deleteOss($file_url){
		$oss_setting_json = D("Options")->get("oss_setting") ;
		$oss_setting = json_decode($oss_setting_json,1);
		if ($oss_setting && $oss_setting['oss_type'] && ( $oss_setting['oss_type'] == 's3_storage' || $oss_setting['oss_type'] == 'aliyun') ) {
			return $this->deleteS3($file_url , $oss_setting);
		}

		if ($oss_setting && $oss_setting['oss_type'] && $oss_setting['oss_type'] == 'qiniu') {
			$oss_setting['endpoint'] = $this->getQiuniuEndpointByKey($oss_setting['key'] , $oss_setting['bucket']);
			return $this->deleteS3($file_url , $oss_setting); 
		}
		//var_dump($config);
		// 腾讯云
		if ($oss_setting && $oss_setting['oss_type'] && $oss_setting['oss_type'] == 'qcloud') {

			// 腾讯云，一开始让用户填写region而没填写endpoint，所以要自己拼接
			$oss_setting['endpoint'] = "https://cos.{$oss_setting['region']}.myqcloud.com";
			// 腾讯云的SecretId相当于s3的key， secretKey相当于s3的secret
			$oss_setting['key'] = $oss_setting['secretId']  ;
			$oss_setting['secret'] = $oss_setting['secretKey']  ;
			return $this->deleteS3($file_url , $oss_setting); 

		}


		return false ;
	}

	// 通过s3协议删除
	// 注意传进来的oss_setting数组需要先转换成合法格式
	public function deleteS3($file_url , $oss_setting){

		$array = parse_url($file_url) ;
		$file = $array['path'] ;  // 得到的是url中的路径，例如/path_.txt
		$file = substr($file, 1); // 要把路径前的/去掉，才是得到文件名path_.txt
		// 如果不包含协议头，自己给它补充
		if(!strstr($oss_setting['endpoint'] , '://')){
			$oss_setting['endpoint'] = 'https://'.$oss_setting['endpoint'] ;
		}

		$s3 = new S3Client([
			'accessKeyId' => $oss_setting['key'],
			'accessKeySecret' => $oss_setting['secret'] ,
			'endpoint' => $oss_setting['endpoint'] ,
		]);
	
		// Send a PutObject request and get the result object.
		$resObj = $s3->deleteObject([
			'Bucket' => $oss_setting['bucket'],
			'Key'    => $file,
		]);

		// 不抛出异常，默认就是成功的


	}

	// 由于历史原因，当初没有让用户填写七牛云的region。而且即使填写了，也不能直接获取到七牛云s3兼容协议上传的endpoint
	// 所以，需要自己调接口查询然后拼凑。七牛这个坑货。
	public function getQiuniuEndpointByKey($key,$bucket){

		$query_url = "https://api.qiniu.com/v2/query?ak={$key}&bucket={$bucket}";
		$res = http_post($query_url,array());

		$array = json_decode($res,true) ;
		// var_dump($array);exit();
		if($array && $array['region'] ){
			switch ($array['region']) {
				case 'z0':
					return 'https://s3-cn-east-1.qiniucs.com';
					break;
				case 'z1':
					return 'https://s3-cn-north-1.qiniucs.com';
					break;
				case 'z2':
					return 'https://s3-cn-south-1.qiniucs.com';
					break;
				case 'na0':
					return 'https://s3-us-north-1.qiniucs.com';
					break;
				case 'as0':
					return 'https://s3-ap-southeast-1.qiniucs.com';
					break;
				default:
					return false;
					break;
			}

		}

	}

	// 判断文件名是否包含危险的扩展名
	public function isDangerFilename($filename){

		$isDangerStr = function ($filename , $keyword){
			if(strstr(strip_tags(strtolower( $filename )), $keyword) ){
				return true ;
			}
			return false;
		};
		if (
			 $isDangerStr($filename , ".php")
			|| $isDangerStr($filename , ".svg")
			|| $isDangerStr($filename , ".htm")
			|| $isDangerStr($filename , "%")
			|| $isDangerStr($filename , ".xml")
		) {
			return true;
		}
	
		return false;
	}



}