Bug 1568341 - Part 1: Add a component for consuming the anti-tracking-url-decoration remote settings bucket and making it available to content processes; r=baku

Differential Revision: https://phabricator.services.mozilla.com/D39919

--HG--
extra : moz-landing-system : lando

modules/libpref/init/all.js

@@ -1137,6 +1137,10 @@ pref("privacy.restrict3rdpartystorage.partitionedHosts", "accounts.google.com/o/
 // before granting the storage access permission.
 pref("privacy.restrict3rdpartystorage.userInteractionRequiredForHosts", "");
 
+// The url decoration tokens used to for stripping document referrers based on.
+// A list separated by spaces.  This pref isn't meant to be changed by users.
+pref("privacy.restrict3rdpartystorage.url_decorations", "");
+
 // Excessive reporting of blocked popups can be a DOS vector,
 // by overloading the main process as popups get blocked and when
 // users try to restore all popups, which is the most visible

toolkit/components/antitracking/URLDecorationAnnotationsService.jsm

@@ -0,0 +1,70 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+this.URLDecorationAnnotationsService = function() {};
+
+const { Preferences } = ChromeUtils.import(
+  "resource://gre/modules/Preferences.jsm"
+);
+
+ChromeUtils.defineModuleGetter(
+  this,
+  "RemoteSettings",
+  "resource://services-settings/remote-settings.js"
+);
+
+const COLLECTION_NAME = "anti-tracking-url-decoration";
+const PREF_NAME = "privacy.restrict3rdpartystorage.url_decorations";
+
+URLDecorationAnnotationsService.prototype = {
+  classID: Components.ID("{5874af6d-5719-4e1b-b155-ef4eae7fcb32}"),
+  QueryInterface: ChromeUtils.generateQI([
+    Ci.nsIObserver,
+    Ci.nsIURLDecorationAnnotationsService,
+  ]),
+
+  _initialized: false,
+
+  onDataAvailable(entries) {
+    // Use this technique in order to ensure the pref cannot be changed by the
+    // user e.g. through about:config.  This preferences is only intended as a
+    // mechanism for reflecting this data to content processes.
+    Preferences.unlock(PREF_NAME);
+    new Preferences({ defaultBranch: true }).set(
+      PREF_NAME,
+      entries.map(x => x.token.replace(/ /, "%20")).join(" ")
+    );
+    Preferences.lock(PREF_NAME);
+  },
+
+  observe(aSubject, aTopic, aData) {
+    if (aTopic == "profile-after-change") {
+      this.ensureUpdated();
+    }
+  },
+
+  ensureUpdated() {
+    if (this._initialized) {
+      return Promise.resolve();
+    }
+    this._initialized = true;
+
+    const client = RemoteSettings(COLLECTION_NAME);
+    client.on("sync", event => {
+      let {
+        data: { current },
+      } = event;
+      this.onDataAvailable(current);
+    });
+
+    // Now trigger an update from the server if necessary to get a fresh copy
+    // of the data
+    return client.get({}).then(entries => {
+      this.onDataAvailable(entries);
+      return undefined;
+    });
+  },
+};
+
+var EXPORTED_SYMBOLS = ["URLDecorationAnnotationsService"];

toolkit/components/antitracking/antitracking.manifest

@@ -0,0 +1 @@
+category profile-after-change URLDecorationAnnotationsService @mozilla.org/tracking-url-decoration-service;1 process=main

toolkit/components/antitracking/components.conf

@@ -11,4 +11,11 @@ Classes = [
         'jsm': 'resource://gre/modules/TrackingDBService.jsm',
         'constructor': 'TrackingDBService',
     },
+    {
+        'cid': '{5874af6d-5719-4e1b-b155-ef4eae7fcb32}',
+        'contract_ids': ['@mozilla.org/tracking-url-decoration-service;1'],
+        'jsm': 'resource://gre/modules/URLDecorationAnnotationsService.jsm',
+        'constructor': 'URLDecorationAnnotationsService',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
 ]

toolkit/components/antitracking/moz.build

@@ -9,12 +9,18 @@ with Files('**'):
 
 XPIDL_SOURCES += [
     'nsITrackingDBService.idl',
+    'nsIURLDecorationAnnotationsService.idl',
 ]
 
 XPIDL_MODULE = 'toolkit_antitracking'
 
+EXTRA_COMPONENTS += [
+    'antitracking.manifest',
+]
+
 EXTRA_JS_MODULES += [
     'TrackingDBService.jsm',
+    'URLDecorationAnnotationsService.jsm',
 ]
 
 XPCOM_MANIFESTS += [

toolkit/components/antitracking/nsIURLDecorationAnnotationsService.idl

@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+/**
+ * A service that monitors updates to the anti-tracking URL decoration
+ * annotations from remote settings.
+ */
+[scriptable, uuid(937d0c66-6821-4e3f-9e04-50dbc2b2b476)]
+interface nsIURLDecorationAnnotationsService : nsISupports
+{
+  /**
+   * Ensures that the list is updated and resolves the returned promise when
+   * the update is finished.
+   *
+   * The new list will be written to a space-separated list of tokens inside
+   * the following string preference:
+   *   privacy.restrict3rdpartystorage.url_decorations
+   *
+   * This preference will be kept up to date with future list updates from
+   * the remote settings server.  This preference cannot be modified by any
+   * external component and is managed by this service.
+   */
+  Promise ensureUpdated();
+};