Bug 1535049 - If the homepage is referenced in the ignore list, reset it soon after startup or when the ignore list is updated. r=daleharvey

Differential Revision: https://phabricator.services.mozilla.com/D40392

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

browser/base/content/browser.js

@@ -2035,6 +2035,7 @@ var gBrowserInit = {
     BrowserSearch.delayedStartupInit();
     AutoShowBookmarksToolbar.init();
     gProtectionsHandler.init();
+    HomePage.init().catch(Cu.reportError);
 
     let safeMode = document.getElementById("helpSafeMode");
     if (Services.appinfo.inSafeMode) {

browser/modules/HomePage.jsm

@@ -2,22 +2,25 @@
  * 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/. */
 
-/* globals ChromeUtils, Services */
-/* exported HomePage */
-
 "use strict";
 
 var EXPORTED_SYMBOLS = ["HomePage"];
 
-const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
-ChromeUtils.defineModuleGetter(
-  this,
-  "PrivateBrowsingUtils",
-  "resource://gre/modules/PrivateBrowsingUtils.jsm"
+const { XPCOMUtils } = ChromeUtils.import(
+  "resource://gre/modules/XPCOMUtils.jsm"
 );
 
+XPCOMUtils.defineLazyModuleGetters(this, {
+  IgnoreLists: "resource://gre/modules/IgnoreLists.jsm",
+  PrivateBrowsingUtils: "resource://gre/modules/PrivateBrowsingUtils.jsm",
+  Services: "resource://gre/modules/Services.jsm",
+});
+
 const kPrefName = "browser.startup.homepage";
 const kDefaultHomePage = "about:home";
+const kExtensionControllerPref =
+  "browser.startup.homepage_override.extensionControlled";
+const kHomePageIgnoreListId = "homepage-urls";
 
 function getHomepagePref(useDefault) {
   let homePage;
@@ -47,7 +50,55 @@ function getHomepagePref(useDefault) {
   return homePage;
 }
 
+/**
+ * HomePage provides tools to keep try of the current homepage, and the
+ * applications's default homepage. It includes tools to insure that certain
+ * urls are ignored. As a result, all set/get requests for the homepage
+ * preferences should be routed through here.
+ */
 let HomePage = {
+  // This is an array of strings that should be matched against URLs to see
+  // if they should be ignored or not.
+  _ignoreList: [],
+
+  // A promise that is set when initialization starts and resolved when it
+  // completes.
+  _initializationPromise: null,
+
+  /**
+   * Used to initialise the ignore lists. This may be called later than
+   * the first call to get or set, which may cause a used to get an ignored
+   * homepage, but this is deemed acceptable, as we'll correct it once
+   * initialised.
+   */
+  async init() {
+    if (this._initializationPromise) {
+      await this._initializationPromise;
+      return;
+    }
+
+    // Now we have the values, listen for future updates.
+    this._ignoreListListener = this._handleIgnoreListUpdated.bind(this);
+
+    this._initializationPromise = IgnoreLists.getAndSubscribe(
+      this._ignoreListListener
+    );
+
+    const current = await this._initializationPromise;
+
+    await this._handleIgnoreListUpdated({ data: { current } });
+  },
+
+  /**
+   * Gets the homepage for the given window.
+   *
+   * @param {DOMWindow} [aWindow]
+   *   The window associated with the get, used to check for private browsing
+   *   mode. If not supplied, normal mode is assumed.
+   * @returns {string}
+   *   Returns the home page value, this could be a single url, or a `|`
+   *   separated list of URLs.
+   */
   get(aWindow) {
     let homePages = getHomepagePref();
     if (
@@ -57,7 +108,7 @@ let HomePage = {
       // If an extension controls the setting and does not have private
       // browsing permission, use the default setting.
       let extensionControlled = Services.prefs.getBoolPref(
-        "browser.startup.homepage_override.extensionControlled",
+        kExtensionControllerPref,
         false
       );
       let privateAllowed = Services.prefs.getBoolPref(
@@ -77,31 +128,88 @@ let HomePage = {
     return homePages;
   },
 
+  /**
+   * @returns {string}
+   *   Returns the application default homepage.
+   */
   getDefault() {
     return getHomepagePref(true);
   },
 
+  /**
+   * @returns {boolean}
+   *   Returns true if the homepage has been changed.
+   */
   get overridden() {
     return Services.prefs.prefHasUserValue(kPrefName);
   },
 
+  /**
+   * @returns {boolean}
+   *   Returns true if the homepage preference is locked.
+   */
   get locked() {
     return Services.prefs.prefIsLocked(kPrefName);
   },
 
+  /**
+   * @returns {boolean}
+   *   Returns true if the current homepage is the application default.
+   */
   get isDefault() {
     return HomePage.get() === kDefaultHomePage;
   },
 
+  /**
+   * Sets the homepage preference to a new page.
+   *
+   * @param {string} value
+   *   The new value to set the preference to. This could be a single url, or a
+   *   `|` separated list of URLs.
+   */
   set(value) {
     Services.prefs.setStringPref(kPrefName, value);
   },
 
+  /**
+   * Clears the homepage preference if it is not the default. Note that for
+   * policy/locking use, the default homepage might not be about:home after this.
+   */
   clear() {
     Services.prefs.clearUserPref(kPrefName);
   },
 
+  /**
+   * Resets the homepage preference to be about:home.
+   */
   reset() {
     Services.prefs.setStringPref(kPrefName, kDefaultHomePage);
   },
+
+  /**
+   * Handles updates of the ignore list, checking the existing preference and
+   * correcting it as necessary.
+   *
+   * @param {Object} eventData
+   *   The event data as received from RemoteSettings.
+   */
+  _handleIgnoreListUpdated({ data: { current } }) {
+    for (const entry of current) {
+      if (entry.id == kHomePageIgnoreListId) {
+        this._ignoreList = [...entry.matches];
+      }
+    }
+
+    // Only check if we're overridden as we assume the default value is fine,
+    // or won't be changeable (e.g. enterprise policy).
+    if (this.overridden) {
+      let homePages = getHomepagePref().toLowerCase();
+      if (
+        this._ignoreList.some(code => homePages.includes(code.toLowerCase()))
+      ) {
+        this.clear();
+        Services.prefs.clearUserPref(kExtensionControllerPref);
+      }
+    }
+  },
 };

browser/modules/test/unit/test_HomePage.js

@@ -2,13 +2,41 @@
  * http://creativecommons.org/publicdomain/zero/1.0/
  */
 
-/* globals ChromeUtils, Services, Cc, Ci, HomePage, Assert, add_task */
 "use strict";
 
-const { HomePage } = ChromeUtils.import("resource:///modules/HomePage.jsm");
-const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
+const { XPCOMUtils } = ChromeUtils.import(
+  "resource://gre/modules/XPCOMUtils.jsm"
+);
 
-add_task(function testHomePage() {
+XPCOMUtils.defineLazyModuleGetters(this, {
+  HomePage: "resource:///modules/HomePage.jsm",
+  Services: "resource://gre/modules/Services.jsm",
+  RemoteSettings: "resource://services-settings/remote-settings.js",
+  // RemoteSettingsClient: "resource://services-settings/RemoteSettingsClient.jsm",
+  sinon: "resource://testing-common/Sinon.jsm",
+});
+
+const HOMEPAGE_IGNORELIST = "homepage-urls";
+
+/**
+ * Provides a basic set of remote settings for use in tests.
+ */
+async function setupRemoteSettings() {
+  const settings = await RemoteSettings("hijack-blocklists");
+  sinon.stub(settings, "get").returns([
+    {
+      id: HOMEPAGE_IGNORELIST,
+      matches: ["ignore=me"],
+      _status: "synced",
+    },
+  ]);
+}
+
+add_task(async function setup() {
+  await setupRemoteSettings();
+});
+
+add_task(function test_HomePage() {
   Assert.ok(
     !HomePage.overridden,
     "Homepage should not be overriden by default."
@@ -34,7 +62,7 @@ add_task(function testHomePage() {
   );
 });
 
-add_task(function readLocalizedHomepage() {
+add_task(function test_readLocalizedHomepage() {
   let newvalue = "data:text/plain,browser.startup.homepage%3Dabout%3Alocalized";
   let complexvalue = Cc["@mozilla.org/pref-localizedstring;1"].createInstance(
     Ci.nsIPrefLocalizedString
@@ -51,7 +79,7 @@ add_task(function readLocalizedHomepage() {
   Assert.equal(HomePage.get(), "about:localized", "Get value from bundle");
 });
 
-add_task(function recoverEmptyHomepage() {
+add_task(function test_recoverEmptyHomepage() {
   Assert.ok(
     !HomePage.overridden,
     "Homepage should not be overriden by default."
@@ -61,3 +89,49 @@ add_task(function recoverEmptyHomepage() {
   Assert.equal(HomePage.get(), HomePage.getDefault(), "Recover is default");
   Assert.ok(!HomePage.overridden, "Recover should have set default");
 });
+
+add_task(async function test_initWithIgnoredPageCausesReset() {
+  HomePage.set("http://bad/?ignore=me");
+  Assert.ok(HomePage.overridden, "Should have overriden the homepage");
+
+  await HomePage.init();
+
+  Assert.ok(
+    !HomePage.overridden,
+    "Should no longer be overriding the homepage."
+  );
+  Assert.equal(
+    HomePage.get(),
+    HomePage.getDefault(),
+    "Should have reset to the default preference"
+  );
+});
+
+add_task(async function test_updateIgnoreListCausesReset() {
+  HomePage.set("http://bad/?new=ignore");
+  Assert.ok(HomePage.overridden, "Should have overriden the homepage");
+
+  // Simulate an ignore list update.
+  await RemoteSettings("hijack-blocklists").emit("sync", {
+    data: {
+      current: [
+        {
+          id: HOMEPAGE_IGNORELIST,
+          schema: 1553857697843,
+          last_modified: 1553859483588,
+          matches: ["ignore=me", "new=ignore"],
+        },
+      ],
+    },
+  });
+
+  Assert.ok(
+    !HomePage.overridden,
+    "Should no longer be overriding the homepage."
+  );
+  Assert.equal(
+    HomePage.get(),
+    HomePage.getDefault(),
+    "Should have reset to the default preference"
+  );
+});