[mv3] Mitigation: Inject CSS user styles to enforce cosmetic filtering

Related issues:
- https://github.com/uBlockOrigin/uBOL-issues/issues/5#issuecomment-1575425913
- https://github.com/w3c/webextensions/issues/403

Currently, there is no other way to inject CSS user styles than to
wake up the service worker, so that it can inject the CSS styles
itself using the `scripting.insertCSS()` method.

If ever the MV3 API supports injecting CSS user styles directly
from a content script, uBOL will be back to be fully declarative.

At this point the service worker is very lightweight since the
filtering is completely  declarative, so this is not too much of
an issue performance-wise except for the fact that waking up the
service worker for the sole purpose of injecting CSS user styles
and nothing else introduces a pointless overhead.

Hopefully the MV3 API will mature to address such inefficiency.

platform/mv3/extension/js/background.js

@@ -53,6 +53,10 @@ import {
     syncWithBrowserPermissions,
 } from './mode-manager.js';
 
+import {
+    ubolLog,
+} from './utils.js';
+
 /******************************************************************************/
 
 const rulesetConfig = {
@@ -169,6 +173,28 @@ async function onPermissionsRemoved() {
 
 function onMessage(request, sender, callback) {
 
+    // Does not require trusted origin.
+
+    switch ( request.what ) {
+
+    case 'insertCSS': {
+        const tabId = sender?.tab?.id ?? false;
+        const frameId = sender?.frameId ?? false;
+        if ( tabId === false || frameId === false ) { return; }
+        browser.scripting.insertCSS({
+            css: request.css,
+            origin: 'USER',
+            target: { tabId, frameIds: [ frameId ] },
+        });
+        return;
+    }
+
+    default:
+        break;
+    }
+
+    // Does requires trusted origin.
+
     // https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/runtime/MessageSender
     //   Firefox API does not set `sender.origin`
     if ( sender.origin !== undefined && sender.origin !== UBOL_ORIGIN ) { return; }
@@ -284,7 +310,7 @@ async function start() {
     // We need to update the regex rules only when ruleset version changes.
     const currentVersion = getCurrentVersion();
     if ( currentVersion !== rulesetConfig.version ) {
-        console.log(`Version change: ${rulesetConfig.version} => ${currentVersion}`);
+        ubolLog(`Version change: ${rulesetConfig.version} => ${currentVersion}`);
         updateDynamicRules().then(( ) => {
             rulesetConfig.version = currentVersion;
             saveRulesetConfig();
@@ -300,10 +326,10 @@ async function start() {
     registerInjectables();
 
     const enabledRulesets = await dnr.getEnabledRulesets();
-    console.log(`Enabled rulesets: ${enabledRulesets}`);
+    ubolLog(`Enabled rulesets: ${enabledRulesets}`);
 
     dnr.getAvailableStaticRuleCount().then(count => {
-        console.log(`Available static rule count: ${count}`);
+        ubolLog(`Available static rule count: ${count}`);
     });
 
     // https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/declarativeNetRequest

platform/mv3/extension/js/ruleset-manager.js

@@ -27,6 +27,7 @@
 
 import { browser, dnr, i18n } from './ext.js';
 import { fetchJSON } from './fetch.js';
+import { ubolLog } from './utils.js';
 
 /******************************************************************************/
 
@@ -72,8 +73,8 @@ function getDynamicRules() {
         const map = new Map(
             rules.map(rule => [ rule.id, rule ])
         );
-        console.info(`Dynamic rule count: ${map.size}`);
-        console.info(`Available dynamic rule count: ${dnr.MAX_NUMBER_OF_DYNAMIC_AND_SESSION_RULES - map.size}`);
+        ubolLog(`Dynamic rule count: ${map.size}`);
+        ubolLog(`Available dynamic rule count: ${dnr.MAX_NUMBER_OF_DYNAMIC_AND_SESSION_RULES - map.size}`);
         return map;
     });
     return dynamicRuleMapPromise;
@@ -142,7 +143,7 @@ async function updateRegexRules() {
         }
     }
     if ( rejectedRegexRules.length !== 0 ) {
-        console.info(
+        ubolLog(
             'Rejected regexes:',
             rejectedRegexRules.map(rule => rule.condition.regexFilter)
         );
@@ -178,10 +179,10 @@ async function updateRegexRules() {
     if ( addRules.length === 0 && removeRuleIds.length === 0 ) { return; }
 
     if ( removeRuleIds.length !== 0 ) {
-        console.info(`Remove ${removeRuleIds.length} DNR regex rules`);
+        ubolLog(`Remove ${removeRuleIds.length} DNR regex rules`);
     }
     if ( addRules.length !== 0 ) {
-        console.info(`Add ${addRules.length} DNR regex rules`);
+        ubolLog(`Add ${addRules.length} DNR regex rules`);
     }
 
     return dnr.updateDynamicRules({ addRules, removeRuleIds });
@@ -250,10 +251,10 @@ async function updateRemoveparamRules() {
     if ( addRules.length === 0 && removeRuleIds.length === 0 ) { return; }
 
     if ( removeRuleIds.length !== 0 ) {
-        console.info(`Remove ${removeRuleIds.length} DNR removeparam rules`);
+        ubolLog(`Remove ${removeRuleIds.length} DNR removeparam rules`);
     }
     if ( addRules.length !== 0 ) {
-        console.info(`Add ${addRules.length} DNR removeparam rules`);
+        ubolLog(`Add ${addRules.length} DNR removeparam rules`);
     }
 
     return dnr.updateDynamicRules({ addRules, removeRuleIds });
@@ -322,10 +323,10 @@ async function updateRedirectRules() {
     if ( addRules.length === 0 && removeRuleIds.length === 0 ) { return; }
 
     if ( removeRuleIds.length !== 0 ) {
-        console.info(`Remove ${removeRuleIds.length} DNR redirect rules`);
+        ubolLog(`Remove ${removeRuleIds.length} DNR redirect rules`);
     }
     if ( addRules.length !== 0 ) {
-        console.info(`Add ${addRules.length} DNR redirect rules`);
+        ubolLog(`Add ${addRules.length} DNR redirect rules`);
     }
 
     return dnr.updateDynamicRules({ addRules, removeRuleIds });
@@ -394,10 +395,10 @@ async function updateCspRules() {
     if ( addRules.length === 0 && removeRuleIds.length === 0 ) { return; }
 
     if ( removeRuleIds.length !== 0 ) {
-        console.info(`Remove ${removeRuleIds.length} DNR csp rules`);
+        ubolLog(`Remove ${removeRuleIds.length} DNR csp rules`);
     }
     if ( addRules.length !== 0 ) {
-        console.info(`Add ${addRules.length} DNR csp rules`);
+        ubolLog(`Add ${addRules.length} DNR csp rules`);
     }
 
     return dnr.updateDynamicRules({ addRules, removeRuleIds });
@@ -482,10 +483,10 @@ async function enableRulesets(ids) {
     const disableRulesetIds = Array.from(disableRulesetSet);
 
     if ( enableRulesetIds.length !== 0 ) {
-        console.info(`Enable rulesets: ${enableRulesetIds}`);
+        ubolLog(`Enable rulesets: ${enableRulesetIds}`);
     }
     if ( disableRulesetIds.length !== 0 ) {
-        console.info(`Disable ruleset: ${disableRulesetIds}`);
+        ubolLog(`Disable ruleset: ${disableRulesetIds}`);
     }
     await dnr.updateEnabledRulesets({ enableRulesetIds, disableRulesetIds });
     

platform/mv3/extension/js/scripting-manager.js

@@ -472,21 +472,21 @@ async function registerInjectables(origins) {
     toRemove.push(...Array.from(before.keys()));
 
     if ( toRemove.length !== 0 ) {
-        console.info(`Unregistered ${toRemove} content (css/js)`);
+        ut.ubolLog(`Unregistered ${toRemove} content (css/js)`);
         promises.push(
             browser.scripting.unregisterContentScripts({ ids: toRemove })
                 .catch(reason => { console.info(reason); })
         );
     }
     if ( toAdd.length !== 0 ) {
-        console.info(`Registered ${toAdd.map(v => v.id)} content (css/js)`);
+        ut.ubolLog(`Registered ${toAdd.map(v => v.id)} content (css/js)`);
         promises.push(
             browser.scripting.registerContentScripts(toAdd)
                 .catch(reason => { console.info(reason); })
         );
     }
     if ( toUpdate.length !== 0 ) {
-        console.info(`Updated ${toUpdate.map(v => v.id)} content (css/js)`);
+        ut.ubolLog(`Updated ${toUpdate.map(v => v.id)} content (css/js)`);
         promises.push(
             browser.scripting.updateContentScripts(toUpdate)
                 .catch(reason => { console.info(reason); })

platform/mv3/extension/js/scripting/css-declarative.js

@@ -135,15 +135,13 @@ for ( const selector of selectors ) {
 
 if ( sheetText.length === 0 ) { return; }
 
-try {
-    const sheet = new CSSStyleSheet();
-    sheet.replace(`@layer{${sheetText.join('\n')}}`);
-    document.adoptedStyleSheets = [
-        ...document.adoptedStyleSheets,
-        sheet
-    ];
-} catch(ex) {
-}
+(function uBOL_injectCSS(css, count = 10) {
+    chrome.runtime.sendMessage({ what: 'insertCSS', css }).catch(( ) => {
+        count -= 1;
+        if ( count === 0 ) { return; }
+        uBOL_injectCSS(css, count - 1);
+    });
+})(sheetText.join('\n'));
 
 /******************************************************************************/
 

platform/mv3/extension/js/scripting/css-generic.js

@@ -60,7 +60,7 @@ const hashFromStr = (type, s) => {
     for ( let i = 0; i < len; i += step ) {
         hash = (hash << 5) + hash ^ s.charCodeAt(i);
     }
-    return hash & 0xFF_FFFF;
+    return hash & 0xFFFFFF;
 };
 
 /******************************************************************************/
@@ -162,7 +162,8 @@ const uBOL_processNodes = ( ) => {
     if ( styleSheetTimer !== undefined ) { return; }
     styleSheetTimer = self.requestAnimationFrame(( ) => {
         styleSheetTimer = undefined;
-        uBOL_injectStyleSheet();
+        uBOL_injectCSS(`${styleSheetSelectors.join(',')}{display:none!important;}`);
+        styleSheetSelectors.length = 0;
     });
 };
 
@@ -187,17 +188,12 @@ const uBOL_processChanges = mutations => {
 
 /******************************************************************************/
 
-const uBOL_injectStyleSheet = ( ) => {
-    try {
-        const sheet = new CSSStyleSheet();
-        sheet.replace(`@layer{${styleSheetSelectors.join(',')}{display:none!important;}}`);
-        document.adoptedStyleSheets = [
-            ...document.adoptedStyleSheets,
-            sheet
-        ];
-    } catch(ex) {
-    }
-    styleSheetSelectors.length = 0;
+const uBOL_injectCSS = (css, count = 10) => {
+    chrome.runtime.sendMessage({ what: 'insertCSS', css }).catch(( ) => {
+        count -= 1;
+        if ( count === 0 ) { return; }
+        uBOL_injectCSS(css, count - 1);
+    });
 };
 
 /******************************************************************************/

platform/mv3/extension/js/scripting/css-procedural.js

@@ -103,16 +103,12 @@ if ( selectors.length === 0 ) { return; }
 
 /******************************************************************************/
 
-const addStylesheet = text => {
-    try {
-        const sheet = new CSSStyleSheet();
-        sheet.replace(`@layer{${text}}`);
-        document.adoptedStyleSheets = [
-            ...document.adoptedStyleSheets,
-            sheet
-        ];
-    } catch(ex) {
-    }
+const uBOL_injectCSS = (css, count = 10) => {
+    chrome.runtime.sendMessage({ what: 'insertCSS', css }).catch(( ) => {
+        count -= 1;
+        if ( count === 0 ) { return; }
+        uBOL_injectCSS(css, count - 1);
+    });
 };
 
 const nonVisualElements = {
@@ -641,9 +637,7 @@ class ProceduralFilterer {
         if ( styleToken !== undefined ) { return styleToken; }
         styleToken = this.randomToken();
         this.styleTokenMap.set(style, styleToken);
-        addStylesheet(
-            `[${this.masterToken}][${styleToken}]\n{${style}}\n`,
-        );
+        uBOL_injectCSS(`[${this.masterToken}][${styleToken}]\n{${style}}\n`);
         return styleToken;
     }
 

platform/mv3/extension/js/scripting/css-specific.js

@@ -103,15 +103,13 @@ if ( selectors.length === 0 ) { return; }
 
 /******************************************************************************/
 
-try {
-    const sheet = new CSSStyleSheet();
-    sheet.replace(`@layer{${selectors.join(',')}{display:none!important;}}`);
-    document.adoptedStyleSheets = [
-        ...document.adoptedStyleSheets,
-        sheet
-    ];
-} catch(ex) {
-}
+(function uBOL_injectCSS(css, count = 10) {
+    chrome.runtime.sendMessage({ what: 'insertCSS', css }).catch(( ) => {
+        count -= 1;
+        if ( count === 0 ) { return; }
+        uBOL_injectCSS(css, count - 1);
+    });
+})(`${selectors.join(',')}{display:none!important;}`);
 
 /******************************************************************************/
 

platform/mv3/extension/js/utils.js

@@ -25,6 +25,10 @@
 
 /******************************************************************************/
 
+import { browser } from './ext.js';
+
+/******************************************************************************/
+
 function parsedURLromOrigin(origin) {
     try {
         return new URL(origin);
@@ -119,6 +123,14 @@ const hostnamesFromMatches = origins => {
 
 /******************************************************************************/
 
+const ubolLog = (...args) => {
+    // Do not pollute dev console in stable release.
+    if ( browser.runtime.id === 'ddkjiahejlhfcafbddmgiahcphecmpfh' ) { return; }
+    console.info(...args);
+};
+
+/******************************************************************************/
+
 export {
     parsedURLromOrigin,
     toBroaderHostname,
@@ -128,4 +140,5 @@ export {
     subtractHostnameIters,
     matchesFromHostnames,
     hostnamesFromMatches,
+    ubolLog,
 };

platform/mv3/make-rulesets.js

@@ -358,7 +358,6 @@ async function processNetworkFilters(assetDetails, network) {
 // Load all available scriptlets into a key-val map, where the key is the
 // scriptlet token, and val is the whole content of the file.
 
-const scriptletDealiasingMap = new Map(); 
 let scriptletsMapPromise;
 
 function loadAllSourceScriptlets() {
@@ -367,28 +366,20 @@ function loadAllSourceScriptlets() {
     }
 
     scriptletsMapPromise = fs.readdir('./scriptlets').then(files => {
-        const reScriptletNameOrAlias = /^\/\/\/\s+(?:name|alias)\s+(\S+)/gm;
+        const readTemplateFile = file =>
+            fs.readFile(`./scriptlets/${file}`, { encoding: 'utf8' })
+              .then(text => ({ file, text }));
         const readPromises = [];
         for ( const file of files ) {
-            readPromises.push(
-                fs.readFile(`./scriptlets/${file}`, { encoding: 'utf8' })
-            );
+            readPromises.push(readTemplateFile(file));
         }
         return Promise.all(readPromises).then(results => {
             const originalScriptletMap = new Map();
-            for ( const text of results ) {
-                const aliasSet = new Set();
-                for (;;) {
-                    const match = reScriptletNameOrAlias.exec(text);
-                    if ( match === null ) { break; }
-                    aliasSet.add(match[1]);
-                }
-                if ( aliasSet.size === 0 ) { continue; }
-                const aliases = Array.from(aliasSet);
-                originalScriptletMap.set(aliases[0], text);
-                for ( let i = 0; i < aliases.length; i++ ) {
-                    scriptletDealiasingMap.set(aliases[i], aliases[0]);
-                }
+            for ( const details of results ) {
+                originalScriptletMap.set(
+                    details.file.replace('.template.js', ''),
+                    details.text
+                );
             }
             return originalScriptletMap;
         });
@@ -490,7 +481,7 @@ function groupHostnamesBySelectors(arrayin) {
     const out = Array.from(contentMap).map(a => [
         a[0], {
             a: a[1].a,
-            y: a[1].y ? Array.from(a[1].y).sort(hnSort) : undefined,
+            y: a[1].y ? Array.from(a[1].y).sort(hnSort) : '*',
             n: a[1].n ? Array.from(a[1].n) : undefined,
         }
     ]).sort((a, b) => {
@@ -564,7 +555,6 @@ async function processCosmeticFilters(assetDetails, mapin) {
     // The cosmetic filters will be injected programmatically as content
     // script and the decisions to activate the cosmetic filters will be
     // done at injection time according to the document's hostname.
-    const originalScriptletMap = await loadAllSourceScriptlets();
     const generatedFiles = [];
 
     const argsMap = domainBasedEntries.map(entry => [
@@ -602,6 +592,7 @@ async function processCosmeticFilters(assetDetails, mapin) {
         argsList[i] = details.a;
     }
 
+    const originalScriptletMap = await loadAllSourceScriptlets();
     const patchedScriptlet = originalScriptletMap.get('css-specific')
         .replace(
             '$rulesetId$',

platform/mv3/make-scriptlets.js

@@ -164,7 +164,7 @@ export function compile(details, isTrusted) {
 
 export async function commit(rulesetId, path, writeFn) {
     const scriptletTemplate = await fs.readFile(
-        './scriptlet.template.js',
+        './scriptlets/scriptlet.template.js',
         { encoding: 'utf8' }
     );
     const patchHnMap = hnmap => {

platform/mv3/scriptlets/css-declarative.template.js

@@ -27,10 +27,6 @@
 
 /******************************************************************************/
 
-/// name css-declarative
-
-/******************************************************************************/
-
 // Important!
 // Isolate from global scope
 (function uBOL_cssDeclarativeImport() {

platform/mv3/scriptlets/css-generic.template.js

@@ -25,10 +25,6 @@
 
 /******************************************************************************/
 
-/// name css-generic
-
-/******************************************************************************/
-
 // Important!
 // Isolate from global scope
 (function uBOL_cssGenericImport() {

platform/mv3/scriptlets/css-procedural.template.js

@@ -27,10 +27,6 @@
 
 /******************************************************************************/
 
-/// name css-procedural
-
-/******************************************************************************/
-
 // Important!
 // Isolate from global scope
 (function uBOL_cssProceduralImport() {

platform/mv3/scriptlets/css-specific.entity.js

@@ -1,51 +0,0 @@
-/*******************************************************************************
-
-    uBlock Origin - a browser extension to block requests.
-    Copyright (C) 2019-present 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/uBlock
-*/
-
-/* jshint esversion:11 */
-
-'use strict';
-
-/******************************************************************************/
-
-/// name css-specific.entity
-
-/******************************************************************************/
-
-// Important!
-// Isolate from global scope
-(function uBOL_cssSpecificEntityImport() {
-
-/******************************************************************************/
-
-// $rulesetId$
-
-const argsList = self.$argsList$;
-
-const entitiesMap = new Map(self.$entitiesMap$);
-
-self.specificEntityImports = self.specificEntityImports || [];
-self.specificEntityImports.push({ argsList, entitiesMap });
-
-/******************************************************************************/
-
-})();
-
-/******************************************************************************/

platform/mv3/scriptlets/css-specific.template.js

@@ -27,10 +27,6 @@
 
 /******************************************************************************/
 
-/// name css-specific
-
-/******************************************************************************/
-
 // Important!
 // Isolate from global scope
 (function uBOL_cssSpecificImports() {