/*******************************************************************************

    uMatrix - a Chromium browser extension to black/white list requests.
    Copyright (C) 2017-2018 Raymond Hill

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see {http://www.gnu.org/licenses/}.

    Home: https://github.com/gorhill/uMatrix
*/

'use strict';

/******************************************************************************/
/******************************************************************************/

// Injected into content pages

(function() {

    if ( typeof vAPI !== 'object' ) { return; }

    vAPI.selfScriptSrcReported = vAPI.selfScriptSrcReported || false;
    vAPI.selfWorkerSrcReported = vAPI.selfWorkerSrcReported || false;

    var reBadScriptSrc = /script-src[^;,]+?'(?:unsafe-inline|nonce-[^']+)'/,
        reGoodWorkerSrc = /(?:child|worker)-src[^;,]+?'none'/;

    var handler = function(ev) {
        if (
            ev.isTrusted !== true ||
            ev.originalPolicy.includes('report-uri about:blank') === false
        ) {
            return false;
        }

        // We do not want to report internal resources more than once.
        // However, we do want to report external resources each time.
        // TODO: this could eventually lead to duplicated reports for external
        //       resources if another extension uses the same approach as
        //       uMatrix. Think about what could be done to avoid duplicate
        //       reports.
        var internal = ev.blockedURI.includes('://') === false;

        // Firefox and Chromium differs in how they fill the
        // 'effectiveDirective' property. Need to normalize here.
        var directive = ev.effectiveDirective;
        if ( directive.startsWith('script-src') ) {
            if ( internal && vAPI.selfScriptSrcReported ) { return true; }
            directive = 'script-src';
        } else if (
            directive.startsWith('worker-src') ||
            directive.startsWith('child-src')
        ) {
            if ( internal && vAPI.selfWorkerSrcReported ) { return true; }
            directive = 'worker-src';
        } else {
            return false;
        }

        // Further validate that the policy violation is relevant to uMatrix:
        // the event still could have been fired as a result of a CSP header
        // not injected by uMatrix.
        if ( directive === 'script-src' ) {
            if ( reBadScriptSrc.test(ev.originalPolicy) === true ) {
                return false;
            }
            if ( internal ) {
                vAPI.selfScriptSrcReported = true;
            }
        } else /* if ( directive === 'worker-src' ) */ {
            if ( reGoodWorkerSrc.test(ev.originalPolicy) === false ) {
                return false;
            }
            if ( internal ) {
                vAPI.selfWorkerSrcReported = true;
            }
        }

        vAPI.messaging.send(
            'contentscript.js',
            {
                what: 'securityPolicyViolation',
                directive: directive,
                blockedURI: ev.blockedURI,
                documentURI: ev.documentURI,
                blocked: ev.disposition === 'enforce'
            }
        );

        return true;
    };

    document.addEventListener(
        'securitypolicyviolation',
        function(ev) {
            if ( !handler(ev) ) { return; }
            ev.stopPropagation();
            ev.preventDefault();
        },
        true
    );

})();