5 files changed, 313 insertions, 161 deletions

diff --git a/content/activity_info_server.js b/content/activity_info_server.js
index 81a25fb..aa92b75 100644
--- a/content/activity_info_server.js
+++ b/content/activity_info_server.js
@@ -1,7 +1,8 @@
 /**
- * part of Hachette
- * Informing about activities performed by content script (script injection,
- * script blocking).
+ * This file is part of Haketilo.
+ *
+ * Function: Informing the popup about what happens in the content script
+ *     (script injection, script blocking, etc.).
  *
  * Copyright (C) 2021 Wojtek Kosior
  * Redistribution terms are gathered in the `copyright' file.
@@ -41,7 +42,14 @@ function report_script(script_data)
 
 function report_settings(settings)
 {
-    report_activity("settings", settings);
+    const settings_clone = {};
+    Object.assign(settings_clone, settings)
+    report_activity("settings", settings_clone);
+}
+
+function report_document_type(is_html)
+{
+    report_activity("is_html", is_html);
 }
 
 function report_repo_query_action(update, port)
@@ -91,5 +99,6 @@ function start_activity_info_server()
  * EXPORT start_activity_info_server
  * EXPORT report_script
  * EXPORT report_settings
+ * EXPORT report_document_type
  * EXPORTS_END
  */
diff --git a/content/freezer.js b/content/freezer.js
deleted file mode 100644
index 9dbc95e..0000000
--- a/content/freezer.js
+++ /dev/null
@@ -1,63 +0,0 @@
-/**
- * Helper functions for blocking scripts in pages, based off NoScript's lib/DocumentFreezer.js
- *
- * Copyright (C) 2005-2021 Giorgio Maone - https://maone.net
- * Copyright (C) 2021 jahoti
- * Redistribution terms are gathered in the `copyright' file.
- */
-
-const loaderAttributes = ["href", "src", "data"];
-const jsOrDataUrlRx = /^(?:data:(?:[^,;]*ml|unknown-content-type)|javascript:)/i;
-
-function sanitize_attributes(element) {
-    if (element._frozen)
-	return;
-    let fa = [];
-    let loaders = [];
-    let attributes = element.attributes || [];
-
-    for (let a of attributes) {
-	let name = a.localName.toLowerCase();
-	if (loaderAttributes.includes(name))
-	    if (jsOrDataUrlRx.test(a.value))
-		loaders.push(a);
-
-	else if (name.startsWith("on")) {
-	    console.debug("Removing", a, element.outerHTML);
-	    fa.push(a.cloneNode());
-	    a.value = "";
-	    element[name] = null;
-	}
-    }
-    if (loaders.length) {
-	for (let a of loaders) {
-	    fa.push(a.cloneNode());
-	    a.value = "javascript://frozen";
-	}
-	if ("contentWindow" in element)
-	    element.replaceWith(element = element.cloneNode(true));
-
-    }
-    if (fa.length)
-	element._frozenAttributes = fa;
-    element._frozen = true;
-}
-
-function mozilla_suppress_scripts(e) {
-    if (document.readyState === 'complete') {
-	removeEventListener('beforescriptexecute', blockExecute, true);
-	console.log('Script suppressor has detached.');
-	return;
-    }
-    if (e.isTrusted && !e.target._hachette_payload) {
-	e.preventDefault();
-	console.log('Suppressed script', e.target);
-    }
-};
-
-/*
- * EXPORTS_START
- * EXPORT mozilla_suppress_scripts
- * EXPORT sanitize_attributes
- * EXPORTS_END
- */
diff --git a/content/main.js b/content/main.js
index 9ed557c..ce1ff7a 100644
--- a/content/main.js
+++ b/content/main.js
@@ -1,5 +1,7 @@
 /**
- * Hachette main content script run in all frames
+ * This file is part of Haketilo.
+ *
+ * Function: Main content script that runs in all frames.
  *
  * Copyright (C) 2021 Wojtek Kosior
  * Copyright (C) 2021 jahoti
@@ -9,123 +11,310 @@
 /*
  * IMPORTS_START
  * IMPORT handle_page_actions
- * IMPORT url_extract_target
- * IMPORT gen_unique
  * IMPORT gen_nonce
- * IMPORT csp_rule
  * IMPORT is_privileged_url
- * IMPORT sanitize_attributes
- * IMPORT mozilla_suppress_scripts
+ * IMPORT browser
  * IMPORT is_chrome
  * IMPORT is_mozilla
  * IMPORT start_activity_info_server
+ * IMPORT make_csp_rule
+ * IMPORT csp_header_regex
+ * IMPORT report_settings
  * IMPORTS_END
  */
 
+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);
+
 /*
- * Due to some technical limitations the chosen method of whitelisting sites
- * is to smuggle whitelist indicator in page's url as a "magical" string
- * after '#'. Right now this is only supplemental in HTTP(s) pages where
- * blocking of native scripts also happens through CSP header injection but is
- * necessary for protocols like ftp:// and file://.
- *
- * The code that actually injects the magical string into ftp:// and file://
- * urls has not yet been added to the extension.
+ * In the case of HTML documents:
+ * 1. When injecting some payload we need to sanitize <meta> CSP tags before
+ *    they reach the document.
+ * 2. Only <meta> tags inside <head> are considered valid by the browser and
+ *    need to be considered.
+ * 3. We want to detach <html> from document, wait until its <head> completes
+ *    loading, sanitize it and re-attach <html>.
+ * 4. We shall wait for anything to appear in or after <body> and take that as
+ *    a sign <head> has finished loading.
+ * 5. Otherwise, getting the `DOMContentLoaded' event on the document shall also
+ *    be a sign that <head> is fully loaded.
  */
 
-var nonce = undefined;
+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 handle_mutation(mutations, observer)
+function try_body_started(waiting)
 {
-    if (document.readyState === 'complete') {
-	console.log("mutation handling complete");
-	observer.disconnect();
-	return;
-    }
-    for (const mutation of mutations) {
-	for (const node of mutation.addedNodes)
-	    block_node(node);
+    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 block_nodes_recursively(node)
+function finish_waiting(waiting)
 {
-    block_node(node);
-    for (const child of node.children)
-	block_nodes_recursively(child);
+    if (waiting.finished)
+	return;
+    waiting.finished = true;
+    waiting.observers.forEach(observer => observer.disconnect());
+    setTimeout(waiting.callback, 0);
 }
 
-function block_node(node)
+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)
+{
+    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));
     /*
-     * Modifying <script> element doesn't always prevent its execution in some
-     * Mozilla browsers. This is Chromium-specific code.
+     * Disabling attributes by prepending `-blocked' allows them to still be
+     * relatively easily accessed in case they contain some useful data.
      */
-    if (node.tagName === "SCRIPT") {
-	block_script(node);
-	return;
+    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);
+}
+
+/*
+ * Used to disable `<script>'s and `<meta>'s that have not yet been added to
+ * live DOM (doesn't work for those already added).
+ */
+function sanitize_meta(meta)
+{
+    if (csp_header_regex.test(meta.httpEquiv) && meta.content)
+	block_attribute(meta, "content");
+}
+
+function sanitize_script(script)
+{
+    script.haketilo_blocked_type = script.getAttribute("type");
+    script.type = "text/plain";
+}
+
+/*
+ * Executed after `<script>' has been connected to the DOM, when it is no longer
+ * eligible for being executed by the browser.
+ */
+function desanitize_script(script)
+{
+    script.setAttribute("type", script.haketilo_blocked_type);
+
+    if ([null, undefined].includes(script.haketilo_blocked_type))
+	script.removeAttribute("type");
+
+    delete script.haketilo_blocked_type;
+}
+
+const bad_url_reg = /^data:([^,;]*ml|unknown-content-type)/i;
+function sanitize_urls(element)
+{
+    for (const attr of [...element.attributes || []]
+	       .filter(attr => /^(href|src|data)$/i.test(attr.localName))
+	       .filter(attr => bad_url_reg.test(attr.value)))
+	block_attribute(element, attr.localName, attr.namespaceURI);
+}
+
+function start_data_urls_sanitizing(doc)
+{
+    doc.querySelectorAll("*[href], *[src], *[data]").forEach(sanitize_urls);
+    if (!doc.content_loaded) {
+	const mutation_handler = m => m.addedNodes.forEach(sanitize_urls);
+	const mo = new MutationObserver(ms => ms.forEach(mutation_handler));
+	mo.observe(doc, {childList: true, subtree: true});
+	wait_loaded(doc).then(() => mo.disconnect());
     }
+}
+
+/*
+ * Normally, we block scripts with CSP. However, Mozilla does optimizations that
+ * cause part of the DOM to be loaded when our content scripts get to run. Thus,
+ * before the CSP rules we inject (for non-HTTP pages) become effective, we need
+ * to somehow block the execution of `<script>'s and intrinsics that were
+ * already there. Additionally, some browsers (IceCat 60) seem to have problems
+ * applying this CSP to non-inline `<scripts>' in certain scenarios.
+ */
+function prevent_script_execution(event)
+{
+    if (!event.target.haketilo_payload)
+	event.preventDefault();
+}
 
-    sanitize_attributes(node);
+function mozilla_initial_block(doc)
+{
+    doc.addEventListener("beforescriptexecute", prevent_script_execution);
 
-    if (node.tagName === "HEAD")
-	inject_csp(node);
+    for (const elem of doc.querySelectorAll("*")) {
+	[...elem.attributes].map(attr => attr.localName)
+	    .filter(attr => /^on/.test(attr) && elem.wrappedJSObject[attr])
+	    .forEach(attr => elem.wrappedJSObject[attr] = null);
+    }
 }
 
-function block_script(node)
+/*
+ * Here we block all scripts of a document which might be either and
+ * HTMLDocument or an XMLDocument. Modifying an XML document might disrupt
+ * Mozilla's XML preview. This is an unfortunate thing we have to accept for
+ * now. XML documents *have to* be sanitized as well because they might
+ * contain `<script>' tags (or on* attributes) with namespace declared as
+ * "http://www.w3.org/1999/xhtml" or "http://www.w3.org/2000/svg" which allows
+ * javascript execution.
+ */
+async function sanitize_document(doc, policy)
 {
     /*
-     * Disabling scripts this way allows them to still be relatively
-     * easily accessed in case they contain some useful data.
+     * Blocking of scripts that are in the DOM from the beginning. Needed for
+     * Mozilla.
      */
-    if (node.hasAttribute("type"))
-	node.setAttribute("blocked-type", node.getAttribute("type"));
-    node.setAttribute("type", "application/json");
+    if (is_mozilla)
+	mozilla_initial_block(doc);
+
+    /*
+     * Ensure our CSP rules are employed from the beginning. This CSP injection
+     * method is, when possible, going to be applied together with CSP rules
+     * injected using webRequest.
+     * Using elements namespaced as HTML makes this CSP injection also work for
+     * non-HTML documents.
+     */
+    const html = new DOMParser().parseFromString(`<html><head><meta \
+http-equiv="Content-Security-Policy" content="${make_csp_rule(policy)}"\
+/></head><body>Loading...</body></html>`, "text/html").documentElement;
+
+    /*
+     * Root node gets hijacked now, to be re-attached after <head> is loaded
+     * and sanitized.
+     */
+    const root = doc.documentElement;
+    root.replaceWith(html);
+
+    /*
+     * When we don't inject payload, we neither block document's CSP `<meta>'
+     * tags nor wait for `<head>' to be parsed.
+     */
+    if (policy.has_payload) {
+	await wait_for_head(doc, root);
+
+	root.querySelectorAll("head meta")
+	    .forEach(m => sanitize_meta(m, policy));
+    }
+
+    root.querySelectorAll("script").forEach(s => sanitize_script(s, policy));
+    html.replaceWith(root);
+    root.querySelectorAll("script").forEach(s => desanitize_script(s, policy));
+
+    start_data_urls_sanitizing(doc);
 }
 
-function inject_csp(head)
+async function _disable_service_workers()
 {
-    console.log('injecting CSP');
+    if (!navigator.serviceWorker)
+	return;
 
-    let meta = document.createElement("meta");
-    meta.setAttribute("http-equiv", "Content-Security-Policy");
-    meta.setAttribute("content", csp_rule(nonce));
+    const registrations = await navigator.serviceWorker.getRegistrations();
+    if (registrations.length === 0)
+	return;
+
+    console.warn("Service Workers detected on this page! Unregistering and reloading.");
 
-    if (head.firstElementChild === null)
-	head.appendChild(meta);
-    else
-	head.insertBefore(meta, head.firstElementChild);
+    try {
+	await Promise.all(registrations.map(r => r.unregister()));
+    } finally {
+	location.reload();
+    }
+
+    /* Never actually return! */
+    return new Promise(() => 0);
 }
 
-if (!is_privileged_url(document.URL)) {
-    const targets = url_extract_target(document.URL);
-    if (targets.policy) {
-	if (targets.target2)
-	    window.location.href = targets.base_url + targets.target2;
-	else
-	    history.replaceState(null, "", targets.base_url);
+/*
+ * Trying to use servce workers APIs might result in exceptions, for example
+ * when in a non-HTML document. Because of this, we wrap the function that does
+ * the actual work in a try {} block.
+ */
+async function disable_service_workers()
+{
+    try {
+	await _disable_service_workers()
+    } catch (e) {
+	console.debug("Exception thrown during an attempt to detect and disable service workers.", e);
     }
+}
 
-    const policy = targets.current ? targets.policy : {};
+function synchronously_get_policy(url)
+{
+    const encoded_url = encodeURIComponent(url);
+    const request_url = `${browser.runtime.getURL("dummy")}?url=${encoded_url}`;
 
-    nonce = policy.nonce || gen_nonce();
-    handle_page_actions(nonce);
+    try {
+	var xhttp = new XMLHttpRequest();
+	xhttp.open("GET", request_url, false);
+	xhttp.send();
+    } catch(e) {
+	console.error("Failure to synchronously fetch policy for url.", e);
+	return {allow: false};
+    }
 
-    if (!policy.allow) {
-	block_nodes_recursively(document.documentElement);
+    const policy = /^[^?]*\?settings=(.*)$/.exec(xhttp.responseURL)[1];
+    return JSON.parse(decodeURIComponent(policy));
+}
 
-	if (is_chrome) {
-	    var observer = new MutationObserver(handle_mutation);
-	    observer.observe(document.documentElement, {
-		attributes: true,
-		childList: true,
-		subtree: true
-	    });
-	}
+if (!is_privileged_url(document.URL)) {
+    const policy = synchronously_get_policy(document.URL);
 
-	if (is_mozilla)
-	    addEventListener('beforescriptexecute', mozilla_suppress_scripts, true);
-    }
+    if (!(document instanceof HTMLDocument))
+	delete policy.payload;
+
+    console.debug("current policy", policy);
+
+    report_settings(policy);
+
+    policy.nonce = gen_nonce();
+
+    const doc_ready = Promise.all([
+	policy.allow ? Promise.resolve() : sanitize_document(document, policy),
+	policy.allow ? Promise.resolve() : disable_service_workers(),
+	wait_loaded(document)
+    ]);
+
+    handle_page_actions(policy, doc_ready);
 
     start_activity_info_server();
 }
diff --git a/content/page_actions.js b/content/page_actions.js
index aff56b8..845e452 100644
--- a/content/page_actions.js
+++ b/content/page_actions.js
@@ -1,5 +1,7 @@
 /**
- * Hachette handling of page actions in content scripts
+ * This file is part of Haketilo.
+ *
+ * Function: Handle page actions in a content script.
  *
  * Copyright (C) 2021 Wojtek Kosior
  * Redistribution terms are gathered in the `copyright' file.
@@ -10,14 +12,17 @@
  * IMPORT CONNECTION_TYPE
  * IMPORT browser
  * IMPORT report_script
- * IMPORT report_settings
+ * IMPORT report_document_type
  * IMPORTS_END
  */
 
-var port;
-var loaded = false;
-var scripts_awaiting = [];
-var nonce;
+let policy;
+/* Snapshot url and content type early; these can be changed by other code. */
+let url;
+let is_html;
+let port;
+let loaded = false;
+let scripts_awaiting = [];
 
 function handle_message(message)
 {
@@ -31,11 +36,12 @@ function handle_message(message)
 		scripts_awaiting.push(script_text);
 	}
     }
-    if (action === "settings")
-	report_settings(data);
+    else {
+	console.error(`Bad page action '${action}'.`);
+    }
 }
 
-function document_loaded(event)
+function document_ready(event)
 {
     loaded = true;
 
@@ -47,22 +53,32 @@ function document_loaded(event)
 
 function add_script(script_text)
 {
+    if (!is_html)
+	return;
+
     let script = document.createElement("script");
     script.textContent = script_text;
-    script.setAttribute("nonce", nonce);
-    script._hachette_payload = true;
+    script.setAttribute("nonce", policy.nonce);
+    script.haketilo_payload = true;
     document.body.appendChild(script);
 
     report_script(script_text);
 }
 
-function handle_page_actions(script_nonce) {
-    document.addEventListener("DOMContentLoaded", document_loaded);
-    port = browser.runtime.connect({name : CONNECTION_TYPE.PAGE_ACTIONS});
-    port.onMessage.addListener(handle_message);
-    port.postMessage({url: document.URL});
+function handle_page_actions(_policy, doc_ready_promise) {
+    policy = _policy;
 
-    nonce = script_nonce;
+    url = document.URL;
+    is_html = document instanceof HTMLDocument;
+    report_document_type(is_html);
+
+    doc_ready_promise.then(document_ready);
+
+    if (policy.payload) {
+	port = browser.runtime.connect({name : CONNECTION_TYPE.PAGE_ACTIONS});
+	port.onMessage.addListener(handle_message);
+	port.postMessage({payload: policy.payload});
+    }
 }
 
 /*
diff --git a/content/repo_query.js b/content/repo_query.js
index 3708108..637282c 100644
--- a/content/repo_query.js
+++ b/content/repo_query.js
@@ -1,6 +1,7 @@
 /**
- * part of Hachette
- * Getting available content for site from remote repositories.
+ * This file is part of Haketilo.
+ *
+ * Function: Getting available content for site from remote repositories.
  *
  * Copyright (C) 2021 Wojtek Kosior
  * Redistribution terms are gathered in the `copyright' file.