From 7bedbcbd80eba9359d2e905b7693923c76ce563d Mon Sep 17 00:00:00 2001 From: Wojtek Kosior Date: Mon, 17 Jan 2022 11:20:52 +0100 Subject: move policy enforcing code to a new file, include basic test --- content/policy_enforcing.js | 326 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 326 insertions(+) create mode 100644 content/policy_enforcing.js (limited to 'content') diff --git a/content/policy_enforcing.js b/content/policy_enforcing.js new file mode 100644 index 0000000..25c8b6b --- /dev/null +++ b/content/policy_enforcing.js @@ -0,0 +1,326 @@ +/** + * This file is part of Haketilo. + * + * Function: Enforcing script blocking rules on a given page, working from a + * content script. + * + * Copyright (C) 2021,2022 Wojtek Kosior + * Copyright (C) 2021 jahoti + * + * 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. + * + * As additional permission under GNU GPL version 3 section 7, you + * may distribute forms of that code without the copy of the GNU + * GPL normally required by section 4, provided you include this + * license notice and, in case of non-source distribution, a URL + * through which recipients can access the Corresponding Source. + * If you modify file(s) with this exception, you may extend this + * exception to your version of the file(s), but you are not + * obligated to do so. If you do not wish to do so, delete this + * exception statement from your version. + * + * As a special exception to the GPL, any HTML file which merely + * makes function calls to this code, and for that purpose + * includes it by reference shall be deemed a separate work for + * copyright law purposes. If you modify this code, you may extend + * this exception to your version of the code, but you are not + * obligated to do so. If you do not wish to do so, delete this + * exception statement from your version. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + * I, Wojtek Kosior, thereby promise not to sue for violation of this file's + * license. Although I request that you do not make use of this code in a + * proprietary program, I am not going to enforce this in court. + */ + +#FROM common/misc.js IMPORT gen_nonce + +document.content_loaded = document.readyState === "complete"; +const wait_loaded = e => e.content_loaded ? Promise.resolve() : + new Promise(c => e.addEventListener("DOMContentLoaded", c, {once: true})); + +wait_loaded(document).then(() => document.content_loaded = true); + +/* + * In the case of HTML documents: + * 1. When injecting some payload we need to sanitize CSP tags before + * they reach the document. + * 2. Only tags inside are considered valid by the browser and + * need to be considered. + * 3. We want to detach from document, wait until its completes + * loading, sanitize it and re-attach . + * 4. We shall wait for anything to appear in or after and take that as + * a sign has finished loading. + * 5. Otherwise, getting the `DOMContentLoaded' event on the document shall also + * be a sign that is fully loaded. + */ + +function make_body_start_observer(DOM_element, waiting) { + const observer = new MutationObserver(() => try_body_started(waiting)); + observer.observe(DOM_element, {childList: true}); + return observer; +} + +function try_body_started(waiting) { + const body = waiting.detached_html.querySelector("body"); + + if ((body && (body.firstChild || body.nextSibling)) || + waiting.doc.documentElement.nextSibling) { + finish_waiting(waiting); + return true; + } + + if (body && waiting.observers.length < 2) + waiting.observers.push(make_body_start_observer(body, waiting)); +} + +function finish_waiting(waiting) { + if (waiting.finished) + return; + waiting.finished = true; + waiting.observers.forEach(observer => observer.disconnect()); + setTimeout(waiting.callback, 0); +} + +function _wait_for_head(doc, detached_html, callback) { + const waiting = {doc, detached_html, callback, observers: []}; + + if (try_body_started(waiting)) + return; + + waiting.observers = [make_body_start_observer(detached_html, waiting)]; + + wait_loaded(doc).then(() => finish_waiting(waiting)); +} + +function wait_for_head(doc, detached_html) { + return new Promise(cb => _wait_for_head(doc, detached_html, cb)); +} + +const blocked_str = "blocked"; + +function block_attribute(node, attr, ns=null, replace_with="") { + const [hasa, geta, seta, rema] = ["has", "get", "set", "remove"] + .map(m => (n, ...args) => typeof ns === "string" ? + n[`${m}AttributeNS`](ns, ...args) : n[`${m}Attribute`](...args)); + /* + * Disabling attributes by prepending `blocked-' allows them to still be + * relatively easily accessed in case they contain some useful data. + */ + const construct_name = [attr]; + while (hasa(node, construct_name.join(""))) + construct_name.unshift(blocked_str); + + while (construct_name.length > 1) { + construct_name.shift(); + const name = construct_name.join(""); + seta(node, `${blocked_str}-${name}`, geta(node, name)); + } + + rema(node, attr); + seta(node, attr, replace_with); +} + +/* + * Used to disable `