XSS prevention

TP6 Packaging usage steps ：

① Use composer Carry out orders , install ezyang/htmlpurifier Extended class library
Under project directory

composer require ezyang/htmlpurifier

② stay app/common.php In the definition of remove_xss function

if (!function_exists('remove_xss')) {
    // Use htmlpurifier To guard against xss attack 
    function remove_xss($string){
        // relative index.php Entrance file , introduce HTMLPurifier.auto.php Core documents 
        //require_once './plugins/htmlpurifier/HTMLPurifier.auto.php';
        //  Generate configuration object 
        $cfg = HTMLPurifier_Config::createDefault();
        //  Here is the configuration ：
        $cfg -> set('Core.Encoding', 'UTF-8');
        //  Set the allowed HTML label 
        $cfg -> set('HTML.Allowed','div,b,strong,i,em,a[href|title],ul,ol,li,br,p[style],span[style],img[width|height|alt|src]');
        //  Set the allowed CSS Style attribute 
        $cfg -> set('CSS.AllowedProperties', 'font,font-size,font-weight,font-style,font-family,text-decoration,padding-left,color,background-color,text-align');
        //  Set up a Is it allowed to use... On the label target="_blank"
        $cfg -> set('HTML.TargetBlank', TRUE);
        //  Use configuration to generate objects for filtering 
        $obj = new HTMLPurifier($cfg);
        //  Filter strings 
        return $obj -> purify($string);
    }
}

explain ：htmlpurifier plug-in unit , It will filter out script The label and what the label contains js Code .

Middleware processes data

class Safe
{
    /**
     *  Processing requests 
     *
     * @param \think\Request $request
     * @param \Closure       $next
     * @return Response
     */
    public function handle($request, \Closure $next)
    {
        try {
            //
            #  verification token 、 It can be added directly after the route 
            #  Verification timestamp 
            $this->checkTime();
            #  Verify the signature 
            $this->checkSign();

            return $next($request);
        }catch (Exception $exception) {
            return  json($exception->getMessage());
        }

    }

    /**
     *  Verification timestamp 
     * @throws Exception
     */
    public function checkTime(){
        $client_time = request()->get('timestamp') ?: request()->post('timestamp');
        if (!is_numeric($client_time)) {
            throw new Exception(' Incorrect timestamp format ');
        }
        if (time() - $client_time > 120) {
            throw new Exception(' request timeout ');
        }
    }

    /**
     *  Check the signature 
     */
    public function checkSign(){
        $client_sign = request()->get('sign') ?: request()->post('sign');
        #  Determine whether there is a signature 
        if (!$client_sign) {
            throw new Exception(' Incorrect signature ');
        }

        #  Determine if the signature is correct 
        $server_sign = $this->getSign();

        if ($client_sign != $server_sign) {
            throw new Exception(' Incorrect signature ');
        }
    }

    /**
     *  Get server signature 
     * @return string
     */
    public function getSign(){
        #  Get the parameters of all requests 
        $params = request()->all();
        #  Signature rules 
        #  First step   The parameters participating in the signature do not include the signature itself 、 barring token
        unset($params['sign']);
        unset($params['token']);
        #  The second step   according to ASCII Sort 
        ksort($params);
        $wait_sign = '';
        foreach ($params as $key=> $value) {
            $wait_sign .= $key.'='.$value.'&';
        }
        #  Remove the superfluous &  Symbol 
        $wait_sign = rtrim($wait_sign,'&');
        return  md5($wait_sign);
    }
}

Front end generation sign

<script src="../javaScript-MD5/js/md5.js"></script>
<script>
    // #  Get the parameters of all requests 
    // #  Signature rules 
    // #  First step   The parameters participating in the signature do not include the signature itself 、 barring token
    // #  The second step   according to ASCII Sort 
    // #  Remove the superfluous &  Symbol 
    var params = new Array();
    params['id'] = 1;
    params['name'] = ' Zhang San ';
    var sign = createSign(params);
    params['sign'] = sign;
    var url = 'http://pyg.com/list?'
    for (var i in params) {
        url += i + '=' + params[i] + '&';
    }
    $.ajax({
        url:url,
        dataType:'json',
        success:function (result) {
            console.log(result);
        }
    })
    function createSign(params) {
        var timestamp = Math.ceil((new Date()).getTime()/1000);
        params['timestamp'] = timestamp;
        params.sort();
        var wait_sign = ''
        for (var i in params) {
            wait_sign += i + '=' + params[i] + '&';
        }
        wait_sign = wait_sign.substr(0,wait_sign.length-1);
        console.log(wait_sign)
        sign = hex_md5(wait_sign)
        return sign;
    }
</script>

The second kind ： Encapsulate global filtering method

Set the global filtering method to htmlspecialchars

[ This method will make the payment function of the initial version unusable ]

By default, the framework does not set any global filtering rules , You can app\Request Object filter Global filter properties ：

namespace app;

class Request extends \think\Request
{
    protected $filter = ['htmlspecialchars'];
}