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/**
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* This file is part of Haketilo.
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*
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* Function: Main content script that runs in all frames.
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*
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* Copyright (C) 2021 Wojtek Kosior
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* Copyright (C) 2021 jahoti
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* Redistribution terms are gathered in the `copyright' file.
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*/
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/*
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* IMPORTS_START
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* IMPORT handle_page_actions
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* IMPORT extract_signed
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* IMPORT sign_data
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* IMPORT gen_nonce
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* IMPORT is_privileged_url
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* IMPORT is_chrome
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* IMPORT is_mozilla
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* IMPORT start_activity_info_server
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* IMPORT make_csp_rule
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* IMPORT csp_header_regex
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* IMPORTS_END
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*/
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document.content_loaded = document.readyState === "complete";
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const wait_loaded = e => e.content_loaded ? Promise.resolve() :
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new Promise(c => e.addEventListener("DOMContentLoaded", c, {once: true}));
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wait_loaded(document).then(() => document.content_loaded = true);
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function extract_cookie_policy(cookie, min_time)
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{
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let best_result = {time: -1};
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let policy = null;
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const extracted_signatures = [];
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for (const match of cookie.matchAll(/haketilo-(\w*)=([^;]*)/g)) {
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const new_result = extract_signed(...match.slice(1, 3));
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if (new_result.fail)
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continue;
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extracted_signatures.push(match[1]);
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if (new_result.time < Math.max(min_time, best_result.time))
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continue;
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/* This should succeed - it's our self-produced valid JSON. */
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const new_policy = JSON.parse(decodeURIComponent(new_result.data));
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if (new_policy.url !== document.URL)
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continue;
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best_result = new_result;
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policy = new_policy;
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}
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return [policy, extracted_signatures];
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}
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function extract_url_policy(url, min_time)
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{
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const [base_url, payload, anchor] =
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/^([^#]*)#?([^#]*)(#?.*)$/.exec(url).splice(1, 4);
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const match = /^haketilo_([^_]+)_(.*)$/.exec(payload);
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if (!match)
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return [null, url];
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const result = extract_signed(...match.slice(1, 3));
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if (result.fail)
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return [null, url];
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const original_url = base_url + anchor;
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const policy = result.time < min_time ? null :
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JSON.parse(decodeURIComponent(result.data));
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return [policy.url === original_url ? policy : null, original_url];
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}
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function employ_nonhttp_policy(policy)
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{
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if (!policy.allow)
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return;
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policy.nonce = gen_nonce();
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const [base_url, target] = /^([^#]*)(#?.*)$/.exec(policy.url).slice(1, 3);
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const encoded_policy = encodeURIComponent(JSON.stringify(policy));
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const payload = "haketilo_" +
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sign_data(encoded_policy, new Date().getTime()).join("_");
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const resulting_url = `${base_url}#${payload}${target}`;
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location.href = resulting_url;
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location.reload();
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}
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/*
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* In the case of HTML documents:
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* 1. When injecting some payload we need to sanitize <meta> CSP tags before
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* they reach the document.
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* 2. Only <meta> tags inside <head> are considered valid by the browser and
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* need to be considered.
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* 3. We want to detach <html> from document, wait until its <head> completes
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* loading, sanitize it and re-attach <html>.
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* 4. We shall wait for anything to appear in or after <body> and take that as
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* a sign <head> has finished loading.
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* 5. Otherwise, getting the `DOMContentLoaded' event on the document shall also
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* be a sign that <head> is fully loaded.
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*/
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function make_body_start_observer(DOM_element, waiting)
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{
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const observer = new MutationObserver(() => try_body_started(waiting));
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observer.observe(DOM_element, {childList: true});
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return observer;
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}
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function try_body_started(waiting)
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{
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const body = waiting.detached_html.querySelector("body");
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if ((body && (body.firstChild || body.nextSibling)) ||
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waiting.doc.documentElement.nextSibling) {
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finish_waiting(waiting);
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return true;
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}
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if (body && waiting.observers.length < 2)
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waiting.observers.push(make_body_start_observer(body, waiting));
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}
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function finish_waiting(waiting)
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{
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if (waiting.finished)
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return;
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waiting.finished = true;
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waiting.observers.forEach(observer => observer.disconnect());
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setTimeout(waiting.callback, 0);
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}
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function _wait_for_head(doc, detached_html, callback)
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{
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const waiting = {doc, detached_html, callback, observers: []};
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if (try_body_started(waiting))
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return;
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waiting.observers = [make_body_start_observer(detached_html, waiting)];
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wait_loaded(doc).then(() => finish_waiting(waiting));
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}
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function wait_for_head(doc, detached_html)
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{
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return new Promise(cb => _wait_for_head(doc, detached_html, cb));
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}
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const blocked_str = "blocked";
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function block_attribute(node, attr, ns=null)
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{
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const [hasa, geta, seta, rema] = ["has", "get", "set", "remove"]
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.map(m => (n, ...args) => typeof ns === "string" ?
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n[`${m}AttributeNS`](ns, ...args) : n[`${m}Attribute`](...args));
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/*
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* Disabling attributes by prepending `-blocked' allows them to still be
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* relatively easily accessed in case they contain some useful data.
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*/
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const construct_name = [attr];
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while (hasa(node, construct_name.join("")))
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construct_name.unshift(blocked_str);
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while (construct_name.length > 1) {
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construct_name.shift();
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const name = construct_name.join("");
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seta(node, `${blocked_str}-${name}`, geta(node, name));
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}
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rema(node, attr);
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}
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/*
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* Used to disable `<script>'s and `<meta>'s that have not yet been added to
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* live DOM (doesn't work for those already added).
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*/
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function sanitize_meta(meta)
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{
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if (csp_header_regex.test(meta.httpEquiv) && meta.content)
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block_attribute(meta, "content");
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}
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function sanitize_script(script)
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{
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script.haketilo_blocked_type = script.getAttribute("type");
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script.type = "text/plain";
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}
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/*
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* Executed after `<script>' has been connected to the DOM, when it is no longer
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* eligible for being executed by the browser.
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*/
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function desanitize_script(script)
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{
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script.setAttribute("type", script.haketilo_blocked_type);
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if ([null, undefined].includes(script.haketilo_blocked_type))
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script.removeAttribute("type");
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delete script.haketilo_blocked_type;
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}
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const bad_url_reg = /^data:([^,;]*ml|unknown-content-type)/i;
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function sanitize_urls(element)
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{
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for (const attr of [...element.attributes || []]
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.filter(attr => /^(href|src|data)$/i.test(attr.localName))
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.filter(attr => bad_url_reg.test(attr.value)))
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block_attribute(element, attr.localName, attr.namespaceURI);
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}
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function start_data_urls_sanitizing(doc)
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{
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doc.querySelectorAll("*[href], *[src], *[data]").forEach(sanitize_urls);
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if (!doc.content_loaded) {
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const mutation_handler = m => m.addedNodes.forEach(sanitize_urls);
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const mo = new MutationObserver(ms => ms.forEach(mutation_handler));
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mo.observe(doc, {childList: true, subtree: true});
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wait_loaded(doc).then(() => mo.disconnect());
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}
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}
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/*
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* Normally, we block scripts with CSP. However, Mozilla does optimizations that
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* cause part of the DOM to be loaded when our content scripts get to run. Thus,
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* before the CSP rules we inject (for non-HTTP pages) become effective, we need
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* to somehow block the execution of `<script>'s and intrinsics that were
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* already there. Additionally, some browsers (IceCat 60) seem to have problems
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* applying this CSP to non-inline `<scripts>' in certain scenarios.
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*/
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function prevent_script_execution(event)
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{
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if (!event.target.haketilo_payload)
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event.preventDefault();
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}
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244
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function mozilla_initial_block(doc)
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{
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doc.addEventListener("beforescriptexecute", prevent_script_execution);
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for (const elem of doc.querySelectorAll("*")) {
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[...elem.attributes].map(attr => attr.localName)
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.filter(attr => /^on/.test(attr) && elem.wrappedJSObject[attr])
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251
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.forEach(attr => elem.wrappedJSObject[attr] = null);
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}
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253
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}
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254
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255
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/*
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256
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* Here we block all scripts of a document which might be either and
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257
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* HTMLDocument or an XMLDocument. Modifying an XML document might disrupt
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258
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* Mozilla's XML preview. This is an unfortunate thing we have to accept for
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259
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* now. XML documents *have to* be sanitized as well because they might
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260
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* contain `<script>' tags (or on* attributes) with namespace declared as
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261
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* "http://www.w3.org/1999/xhtml" or "http://www.w3.org/2000/svg" which allows
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262
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* javascript execution.
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263
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*/
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264
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async function sanitize_document(doc, policy)
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265
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{
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266
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/*
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267
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* Blocking of scripts that are in the DOM from the beginning. Needed for
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268
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* Mozilla.
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269
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*/
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270
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if (is_mozilla)
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271
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mozilla_initial_block(doc);
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272
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273
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/*
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274
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* Ensure our CSP rules are employed from the beginning. This CSP injection
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275
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* method is, when possible, going to be applied together with CSP rules
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276
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* injected using webRequest.
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277
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* Using elements namespaced as HTML makes this CSP injection also work for
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278
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* non-HTML documents.
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279
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*/
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280
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const html = new DOMParser().parseFromString(`<html><head><meta \
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281
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http-equiv="Content-Security-Policy" content="${make_csp_rule(policy)}"\
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282
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/></head><body>Loading...</body></html>`, "text/html").documentElement;
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283
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284
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/*
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285
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* Root node gets hijacked now, to be re-attached after <head> is loaded
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286
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* and sanitized.
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287
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*/
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288
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const root = doc.documentElement;
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289
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root.replaceWith(html);
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290
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291
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/*
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292
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* When we don't inject payload, we neither block document's CSP `<meta>'
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293
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* tags nor wait for `<head>' to be parsed.
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294
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*/
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295
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if (policy.has_payload) {
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296
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await wait_for_head(doc, root);
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297
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298
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root.querySelectorAll("head meta")
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299
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.forEach(m => sanitize_meta(m, policy));
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300
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}
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301
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302
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root.querySelectorAll("script").forEach(s => sanitize_script(s, policy));
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303
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html.replaceWith(root);
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304
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root.querySelectorAll("script").forEach(s => desanitize_script(s, policy));
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305
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306
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start_data_urls_sanitizing(doc);
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|
307
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}
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|
308
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309
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async function disable_service_workers()
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|
310
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{
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311
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if (!navigator.serviceWorker)
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312
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return;
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|
313
|
|
|
314
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const registrations = await navigator.serviceWorker.getRegistrations();
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|
315
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if (registrations.length === 0)
|
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316
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return;
|
|
317
|
|
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318
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console.warn("Service Workers detected on this page! Unregistering and reloading");
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|
319
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|
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320
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try {
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321
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await Promise.all(registrations.map(r => r.unregister()));
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322
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} finally {
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323
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location.reload();
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|
324
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}
|
|
325
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|
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326
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/* Never actually return! */
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327
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return new Promise(() => 0);
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|
328
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}
|
|
329
|
|
|
330
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if (!is_privileged_url(document.URL)) {
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331
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let policy_received_callback = () => undefined;
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|
332
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let policy;
|
|
333
|
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334
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/* Signature valid for half an hour. */
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335
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const min_time = new Date().getTime() - 1800 * 1000;
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|
336
|
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337
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if (/^https?:/.test(document.URL)) {
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|
338
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let signatures;
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339
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[policy, signatures] = extract_cookie_policy(document.cookie, min_time);
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340
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for (const signature of signatures)
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341
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document.cookie = `haketilo-${signature}=; Max-Age=-1;`;
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342
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} else {
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343
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const scheme = /^([^:]*)/.exec(document.URL)[1];
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344
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const known_scheme = ["file", "ftp"].includes(scheme);
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345
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346
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if (!known_scheme)
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347
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console.warn(`Unknown url scheme: \`${scheme}'!`);
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|
348
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349
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let original_url;
|
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350
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[policy, original_url] = extract_url_policy(document.URL, min_time);
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|
351
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history.replaceState(null, "", original_url);
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352
|
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353
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if (known_scheme && !policy)
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354
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policy_received_callback = employ_nonhttp_policy;
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355
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}
|
|
356
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|
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357
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if (!policy) {
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358
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console.debug("Using fallback policy!");
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|
359
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policy = {allow: false, nonce: gen_nonce()};
|
|
360
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}
|
|
361
|
|
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362
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if (!(document instanceof HTMLDocument))
|
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363
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policy.has_payload = false;
|
|
364
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|
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365
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console.debug("current policy", policy);
|
|
366
|
|
|
367
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const doc_ready = Promise.all([
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|
368
|
policy.allow ? Promise.resolve() : sanitize_document(document, policy),
|
|
369
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policy.allow ? Promise.resolve() : disable_service_workers(),
|
|
370
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wait_loaded(document)
|
|
371
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]);
|
|
372
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373
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handle_page_actions(policy.nonce, policy_received_callback, doc_ready);
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|
374
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|
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375
|
start_activity_info_server();
|
|
376
|
}
|