Refused to apply inline style because it violates the following Content Security Policy directive

javascript google-chrome-extension content-security-policy

183,866

Solution 1

You can also relax your CSP for styles by adding style-src 'self' 'unsafe-inline';

"content_security_policy": "default-src 'self' style-src 'self' 'unsafe-inline';"

This will allow you to keep using inline style in your extension.

Important note

As others have pointed out, this is not recommended, and you should put all your CSS in a dedicated file. See the OWASP explanation on why CSS can be a vector for attacks (kudos to @ KayakinKoder for the link).

Solution 2

As the error message says, you have an inline style, which CSP prohibits. I see at least one (list-style: none) in your HTML. Put that style in your CSS file instead.

To explain further, Content Security Policy does not allow inline CSS because it could be dangerous. From An Introduction to Content Security Policy:

"If an attacker can inject a script tag that directly contains some malicious payload .. the browser has no mechanism by which to distinguish it from a legitimate inline script tag. CSP solves this problem by banning inline script entirely: it’s the only way to be sure."

Solution 3

Another method is to use the CSSOM (CSS Object Model), via the style property on a DOM node.

var myElem = document.querySelector('.my-selector');
myElem.style.color = 'blue';

More details on CSSOM: https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement.style

As mentioned by others, enabling unsafe-line for css is another method to solve this.

183,866

Author by

João Beirão

Updated on August 28, 2021

Comments

João Beirão over 2 years

So, in about 1 hour my extensions failed hard.

I was doing my extension and it was doing what I pretended. I made some changes, and as I didnt liked I deleted them, and now my extension is throwing error:

Refused to apply inline style because it violates the following Content Security Policy directive: "default-src 'self'". Note that 'style-src' was not explicitly set, so 'default-src' is used as a fallback.

What causes this error?

I made my changes in:

popup.html

<!DOCTYPE html>
<html ng-app="PinIt" ng-csp>
    <head>
        <link rel="stylesheet" href="css/popup.css">
        <script src="js/lib/jquery-1.8.2.min.js"></script>
        <script src="js/lib/angular.min.js"></script>
        <script src="js/app/app.js"></script>
        <script src="js/app/popup.js"></script> 
    </head>
    <body id="popup">
        <header>
            <h1>PinIt</h1>
        </header>
    <div ng-controller="PageController">
            <div>{{message}}</div>
            <h2>Page:</h2>
            <div id="elem">{{title}}</div>
            <div>{{url}}</div>
            <h2>Imagens:</h2>
            <ul>
                <li ng-repeat="pageInfo in pageInfos" style="list-style: none">
                    <div class="imgplusshare">
                    <img src={{pageInfo}} class="imagemPopup"/>
                    <ul class="imas">
                      <li id="liFacebook" ng-click="fbshare(pageInfo)">
                      <span>
                      <img src="facebook_16.png"/>Facebook
                      </span>
                    </li>
                    <li id="liTwitter" ng-click="twshare(pageInfo)">
                    <span>
                    <img src="twitter-bird-16x16.png"/>Twitter
                    </span>
                    </li>
                    <li id="liGooglePlus" ng-click="gpshare(pageInfo)">
                    <span><img src="gplus-16.png"/>Google+</span>
                    </li>
                    <li id="liEmail" ng-click="mailshare(pageInfo)">
                    <span><img src="mail_icon_16.png"/>Email</span>
                    </li>
                    <hr>
                    </ul>

                    </div>
                    </li>

                    </ul>
</div>
    </body>
</html>

popup.js

  myApp.service('pageInfoService', function() {
        this.getInfo = function(callback) {
            var model = {};

            chrome.tabs.query({'active': true},
            function (tabs) {
                if (tabs.length > 0)
                {
                    model.title = tabs[0].title;
                    model.url = tabs[0].url;

                    chrome.tabs.sendMessage(tabs[0].id, { 'action': 'PageInfo' }, function (response) {

                        model.pageInfos = response;

                        callback(model);
                    });

                }

            });
        };
    });
    myApp.controller("PageController", function ($scope, pageInfoService) {

        pageInfoService.getInfo(function (info) {           
            $scope.title = info.title;
            $scope.url = info.url;
            $scope.pageInfos = info.pageInfos;
            $scope.fbshare =  function($src) {
             chrome.windows.create({url:"http://www.facebook.com/sharer/sharer.php?u="+$src});
      };    
            $scope.twshare =  function($src) {
             chrome.windows.create({url:"https://twitter.com/intent/tweet?url="+$src});
      };
            $scope.gpshare =  function($src) {
             chrome.windows.create({url:"https://plus.google.com/share?url="+$src});
      };
            $scope.mailshare =  function($src) {
             chrome.windows.create({url:"mailto:?subject=Imagem Partilhada por PinIt&body=<img src=\""+$src+"\"\\\>"});
      };



            $scope.$apply();


        });
    });

Here is my manifest file:

{
    "name": "PinIt",
    "version": "1.0",
    "manifest_version": 2,

    "description": "Pin It",
    "icons": {
        "128": "icon128.png"
    },
    "browser_action": {
        "default_icon": "img/defaultIcon19x19.png",
        "default_popup": "popup.html",
        "default_title": "PinIt"
    },
    "content_scripts": [ {
    "js": [ "js/lib/jquery-1.8.2.min.js", "js/app/content.js", "js/jquery-ui-1.10.3.custom.js" ],
    "matches": [ "*://*/*" ],
    "run_at": "document_start"
    } ],
    "minimum_chrome_version": "18",
    "permissions": [ "http://*/*", "https://*/*", "unlimitedStorage", "contextMenus", "cookies", "tabs", "notifications" ],
    "content_security_policy": "default-src 'self'"
}

any sugestion?