browser/modules/Sanitizer.jsm
author Cosmin Sabou <csabou@mozilla.com>
Sat, 02 Mar 2019 20:40:01 +0200
changeset 462132 bf3cbcc825276823afba2778333cf62cfa75039c
parent 462020 845e1d0b24022796c587f7121825046cbcbc02f9
child 462471 38db33426dd4b23c453875835a4b39e18725d1e5
permissions -rw-r--r--
Backed out 16 changesets (bug 827976) for causing bug 1532054. a=backout Backed out changeset 54c0b12443ed (bug 827976) Backed out changeset 92b45080d080 (bug 827976) Backed out changeset 443087a359f9 (bug 827976) Backed out changeset f976c2d4cebb (bug 827976) Backed out changeset 66cffb171024 (bug 827976) Backed out changeset 845e1d0b2402 (bug 827976) Backed out changeset fd94066a1d76 (bug 827976) Backed out changeset e253b264e7bd (bug 827976) Backed out changeset 07ef335770a8 (bug 827976) Backed out changeset 9d3805d77b99 (bug 827976) Backed out changeset eed600ceb606 (bug 827976) Backed out changeset 3b64368cff52 (bug 827976) Backed out changeset 69d0378e0c09 (bug 827976) Backed out changeset 9203871a5c6f (bug 827976) Backed out changeset 96a507c818e2 (bug 827976) Backed out changeset e254496ff95b (bug 827976)

// -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
/* 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/. */

var EXPORTED_SYMBOLS = ["Sanitizer"];

const {XPCOMUtils} = ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
const {Services} = ChromeUtils.import("resource://gre/modules/Services.jsm");

XPCOMUtils.defineLazyModuleGetters(this, {
  AppConstants: "resource://gre/modules/AppConstants.jsm",
  PlacesUtils: "resource://gre/modules/PlacesUtils.jsm",
  FormHistory: "resource://gre/modules/FormHistory.jsm",
  ContextualIdentityService: "resource://gre/modules/ContextualIdentityService.jsm",
});

XPCOMUtils.defineLazyServiceGetter(this, "quotaManagerService",
                                   "@mozilla.org/dom/quota-manager-service;1",
                                   "nsIQuotaManagerService");
XPCOMUtils.defineLazyServiceGetter(this, "serviceWorkerManager",
                                   "@mozilla.org/serviceworkers/manager;1",
                                   "nsIServiceWorkerManager");

var logConsole;
function log(msg) {
  if (!logConsole) {
    logConsole = console.createInstance({
      prefix: "** Sanitizer.jsm",
      maxLogLevelPref: "browser.sanitizer.loglevel",
    });
  }

  logConsole.log(msg);
}

// Used as unique id for pending sanitizations.
var gPendingSanitizationSerial = 0;

/**
 * Cookie lifetime policy is currently used to cleanup on shutdown other
 * components such as QuotaManager, localStorage, ServiceWorkers.
 */
const PREF_COOKIE_LIFETIME = "network.cookie.lifetimePolicy";

var Sanitizer = {
  /**
   * Whether we should sanitize on shutdown.
   */
  PREF_SANITIZE_ON_SHUTDOWN: "privacy.sanitize.sanitizeOnShutdown",

  /**
   * During a sanitization this is set to a JSON containing an array of the
   * pending sanitizations. This allows to retry sanitizations on startup in
   * case they dind't run or were interrupted by a crash.
   * Use addPendingSanitization and removePendingSanitization to manage it.
   */
  PREF_PENDING_SANITIZATIONS: "privacy.sanitize.pending",

  /**
   * Pref branches to fetch sanitization options from.
   */
  PREF_CPD_BRANCH: "privacy.cpd.",
  PREF_SHUTDOWN_BRANCH: "privacy.clearOnShutdown.",

  /**
   * The fallback timestamp used when no argument is given to
   * Sanitizer.getClearRange.
   */
  PREF_TIMESPAN: "privacy.sanitize.timeSpan",

  /**
   * Pref to newTab segregation. If true, on shutdown, the private container
   * used in about:newtab is cleaned up.  Exposed because used in tests.
   */
  PREF_NEWTAB_SEGREGATION: "privacy.usercontext.about_newtab_segregation.enabled",

  /**
   * Time span constants corresponding to values of the privacy.sanitize.timeSpan
   * pref.  Used to determine how much history to clear, for various items
   */
  TIMESPAN_EVERYTHING: 0,
  TIMESPAN_HOUR:       1,
  TIMESPAN_2HOURS:     2,
  TIMESPAN_4HOURS:     3,
  TIMESPAN_TODAY:      4,
  TIMESPAN_5MIN:       5,
  TIMESPAN_24HOURS:    6,

  /**
   * Whether we should sanitize on shutdown.
   * When this is set, a pending sanitization should also be added and removed
   * when shutdown sanitization is complete. This allows to retry incomplete
   * sanitizations on startup.
   */
  shouldSanitizeOnShutdown: false,

  /**
   * Whether we should sanitize the private container for about:newtab.
   */
  shouldSanitizeNewTabContainer: false,

  /**
   * Shows a sanitization dialog to the user.
   *
   * @param [optional] parentWindow the window to use as
   *                   parent for the created dialog.
   */
  showUI(parentWindow) {
    let win = AppConstants.platform == "macosx" ?
      null : // make this an app-modal window on Mac
      parentWindow;
    Services.ww.openWindow(win,
                           "chrome://browser/content/sanitize.xul",
                           "Sanitize",
                           "chrome,titlebar,dialog,centerscreen,modal",
                           null);
  },

  /**
   * Performs startup tasks:
   *  - Checks if sanitizations were not completed during the last session.
   *  - Registers sanitize-on-shutdown.
   */
  async onStartup() {
    // First, collect pending sanitizations from the last session, before we
    // add pending sanitizations for this session.
    let pendingSanitizations = getAndClearPendingSanitizations();

    // Check if we should sanitize on shutdown.
    this.shouldSanitizeOnShutdown =
      Services.prefs.getBoolPref(Sanitizer.PREF_SANITIZE_ON_SHUTDOWN, false);
    Services.prefs.addObserver(Sanitizer.PREF_SANITIZE_ON_SHUTDOWN, this, true);
    // Add a pending shutdown sanitization, if necessary.
    if (this.shouldSanitizeOnShutdown) {
      let itemsToClear = getItemsToClearFromPrefBranch(Sanitizer.PREF_SHUTDOWN_BRANCH);
      addPendingSanitization("shutdown", itemsToClear, {});
    }
    // Shutdown sanitization is always pending, but the user may change the
    // sanitize on shutdown prefs during the session. Then the pending
    // sanitization would become stale and must be updated.
    Services.prefs.addObserver(Sanitizer.PREF_SHUTDOWN_BRANCH, this, true);

    // Make sure that we are triggered during shutdown.
    let shutdownClient = PlacesUtils.history.shutdownClient.jsclient;
    // We need to pass to sanitize() (through sanitizeOnShutdown) a state object
    // that tracks the status of the shutdown blocker. This `progress` object
    // will be updated during sanitization and reported with the crash in case of
    // a shutdown timeout.
    // We use the `options` argument to pass the `progress` object to sanitize().
    let progress = { isShutdown: true };
    shutdownClient.addBlocker("sanitize.js: Sanitize on shutdown",
      () => sanitizeOnShutdown(progress),
      {fetchState: () => ({ progress })}
    );

    this.shouldSanitizeNewTabContainer = Services.prefs.getBoolPref(this.PREF_NEWTAB_SEGREGATION, false);
    if (this.shouldSanitizeNewTabContainer) {
      addPendingSanitization("newtab-container", [], {});
    }

    let i = pendingSanitizations.findIndex(s => s.id == "newtab-container");
    if (i != -1) {
      pendingSanitizations.splice(i, 1);
      sanitizeNewTabSegregation();
    }

    // Finally, run the sanitizations that were left pending, because we crashed
    // before completing them.
    for (let {itemsToClear, options} of pendingSanitizations) {
      try {
        await this.sanitize(itemsToClear, options);
      } catch (ex) {
        Cu.reportError("A previously pending sanitization failed: " + itemsToClear + "\n" + ex);
      }
    }
  },

  /**
   * Returns a 2 element array representing the start and end times,
   * in the uSec-since-epoch format that PRTime likes. If we should
   * clear everything, this function returns null.
   *
   * @param ts [optional] a timespan to convert to start and end time.
   *                      Falls back to the privacy.sanitize.timeSpan preference
   *                      if this argument is omitted.
   *                      If this argument is provided, it has to be one of the
   *                      Sanitizer.TIMESPAN_* constants. This function will
   *                      throw an error otherwise.
   *
   * @return {Array} a 2-element Array containing the start and end times.
   */
  getClearRange(ts) {
    if (ts === undefined)
      ts = Services.prefs.getIntPref(Sanitizer.PREF_TIMESPAN);
    if (ts === Sanitizer.TIMESPAN_EVERYTHING)
      return null;

    // PRTime is microseconds while JS time is milliseconds
    var endDate = Date.now() * 1000;
    switch (ts) {
      case Sanitizer.TIMESPAN_5MIN :
        var startDate = endDate - 300000000; // 5*60*1000000
        break;
      case Sanitizer.TIMESPAN_HOUR :
        startDate = endDate - 3600000000; // 1*60*60*1000000
        break;
      case Sanitizer.TIMESPAN_2HOURS :
        startDate = endDate - 7200000000; // 2*60*60*1000000
        break;
      case Sanitizer.TIMESPAN_4HOURS :
        startDate = endDate - 14400000000; // 4*60*60*1000000
        break;
      case Sanitizer.TIMESPAN_TODAY :
        var d = new Date(); // Start with today
        d.setHours(0); // zero us back to midnight...
        d.setMinutes(0);
        d.setSeconds(0);
        d.setMilliseconds(0);
        startDate = d.valueOf() * 1000; // convert to epoch usec
        break;
      case Sanitizer.TIMESPAN_24HOURS :
        startDate = endDate - 86400000000; // 24*60*60*1000000
        break;
      default:
        throw "Invalid time span for clear private data: " + ts;
    }
    return [startDate, endDate];
  },

  /**
   * Deletes privacy sensitive data in a batch, according to user preferences.
   * Returns a promise which is resolved if no errors occurred.  If an error
   * occurs, a message is reported to the console and all other items are still
   * cleared before the promise is finally rejected.
   *
   * @param [optional] itemsToClear
   *        Array of items to be cleared. if specified only those
   *        items get cleared, irrespectively of the preference settings.
   * @param [optional] options
   *        Object whose properties are options for this sanitization:
   *         - ignoreTimespan (default: true): Time span only makes sense in
   *           certain cases.  Consumers who want to only clear some private
   *           data can opt in by setting this to false, and can optionally
   *           specify a specific range.
   *           If timespan is not ignored, and range is not set, sanitize() will
   *           use the value of the timespan pref to determine a range.
   *         - range (default: null)
   *         - privateStateForNewWindow (default: "non-private"): when clearing
   *           open windows, defines the private state for the newly opened window.
   */
  async sanitize(itemsToClear = null, options = {}) {
    let progress = options.progress || {};
    if (!itemsToClear)
      itemsToClear = getItemsToClearFromPrefBranch(this.PREF_CPD_BRANCH);
    let promise = sanitizeInternal(this.items, itemsToClear, progress, options);

    // Depending on preferences, the sanitizer may perform asynchronous
    // work before it starts cleaning up the Places database (e.g. closing
    // windows). We need to make sure that the connection to that database
    // hasn't been closed by the time we use it.
    // Though, if this is a sanitize on shutdown, we already have a blocker.
    if (!progress.isShutdown) {
      let shutdownClient = PlacesUtils.history.shutdownClient.jsclient;
      shutdownClient.addBlocker("sanitize.js: Sanitize",
        promise,
        {
          fetchState: () => ({ progress }),
        }
      );
    }

    try {
      await promise;
    } finally {
      Services.obs.notifyObservers(null, "sanitizer-sanitization-complete");
    }
  },

  observe(subject, topic, data) {
    if (topic == "nsPref:changed") {
      if (data.startsWith(this.PREF_SHUTDOWN_BRANCH) &&
          this.shouldSanitizeOnShutdown) {
        // Update the pending shutdown sanitization.
        removePendingSanitization("shutdown");
        let itemsToClear = getItemsToClearFromPrefBranch(Sanitizer.PREF_SHUTDOWN_BRANCH);
        addPendingSanitization("shutdown", itemsToClear, {});
      } else if (data == this.PREF_SANITIZE_ON_SHUTDOWN) {
        this.shouldSanitizeOnShutdown =
          Services.prefs.getBoolPref(Sanitizer.PREF_SANITIZE_ON_SHUTDOWN, false);
        removePendingSanitization("shutdown");
        if (this.shouldSanitizeOnShutdown) {
          let itemsToClear = getItemsToClearFromPrefBranch(Sanitizer.PREF_SHUTDOWN_BRANCH);
          addPendingSanitization("shutdown", itemsToClear, {});
        }
      } else if (data == this.PREF_NEWTAB_SEGREGATION) {
        this.shouldSanitizeNewTabContainer = Services.prefs.getBoolPref(this.PREF_NEWTAB_SEGREGATION, false);
        removePendingSanitization("newtab-container");
        if (this.shouldSanitizeNewTabContainer) {
          addPendingSanitization("newtab-container", [], {});
        }
      }
    }
  },

  QueryInterface: ChromeUtils.generateQI([
    Ci.nsIObserver,
    Ci.nsISupportsWeakReference,
  ]),

  // This method is meant to be used by tests.
  async runSanitizeOnShutdown() {
    return sanitizeOnShutdown({ isShutdown: true });
  },

  // When making any changes to the sanitize implementations here,
  // please check whether the changes are applicable to Android
  // (mobile/android/modules/Sanitizer.jsm) as well.

  items: {
    cache: {
      async clear(range) {
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_CACHE", refObj);
        await clearData(range, Ci.nsIClearDataService.CLEAR_ALL_CACHES);
        TelemetryStopwatch.finish("FX_SANITIZE_CACHE", refObj);
      },
    },

    cookies: {
      async clear(range) {
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_COOKIES_2", refObj);
        await clearData(range, Ci.nsIClearDataService.CLEAR_COOKIES |
                               Ci.nsIClearDataService.CLEAR_PLUGIN_DATA |
                               Ci.nsIClearDataService.CLEAR_MEDIA_DEVICES);
        TelemetryStopwatch.finish("FX_SANITIZE_COOKIES_2", refObj);
      },
    },

    offlineApps: {
      async clear(range) {
        await clearData(range, Ci.nsIClearDataService.CLEAR_DOM_STORAGES);
      },
    },

    history: {
      async clear(range) {
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_HISTORY", refObj);
        await clearData(range, Ci.nsIClearDataService.CLEAR_HISTORY |
                               Ci.nsIClearDataService.CLEAR_SESSION_HISTORY);
        TelemetryStopwatch.finish("FX_SANITIZE_HISTORY", refObj);
      },
    },

    formdata: {
      async clear(range) {
        let seenException;
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_FORMDATA", refObj);
        try {
          // Clear undo history of all search bars.
          for (let currentWindow of Services.wm.getEnumerator("navigator:browser")) {
            let currentDocument = currentWindow.document;

            // searchBar.textbox may not exist due to the search bar binding
            // not having been constructed yet if the search bar is in the
            // overflow or menu panel. It won't have a value or edit history in
            // that case.
            let searchBar = currentDocument.getElementById("searchbar");
            if (searchBar && searchBar.textbox)
              searchBar.textbox.reset();

            let tabBrowser = currentWindow.gBrowser;
            if (!tabBrowser) {
              // No tab browser? This means that it's too early during startup (typically,
              // Session Restore hasn't completed yet). Since we don't have find
              // bars at that stage and since Session Restore will not restore
              // find bars further down during startup, we have nothing to clear.
              continue;
            }
            for (let tab of tabBrowser.tabs) {
              if (tabBrowser.isFindBarInitialized(tab))
                tabBrowser.getCachedFindBar(tab).clear();
            }
            // Clear any saved find value
            tabBrowser._lastFindValue = "";
          }
        } catch (ex) {
          seenException = ex;
        }

        try {
          let change = { op: "remove" };
          if (range) {
            [ change.firstUsedStart, change.firstUsedEnd ] = range;
          }
          await new Promise(resolve => {
            FormHistory.update(change, {
              handleError(e) {
                seenException = new Error("Error " + e.result + ": " + e.message);
              },
              handleCompletion() {
                resolve();
              },
            });
          });
        } catch (ex) {
          seenException = ex;
        }

        TelemetryStopwatch.finish("FX_SANITIZE_FORMDATA", refObj);
        if (seenException) {
          throw seenException;
        }
      },
    },

    downloads: {
      async clear(range) {
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_DOWNLOADS", refObj);
        await clearData(range, Ci.nsIClearDataService.CLEAR_DOWNLOADS);
        TelemetryStopwatch.finish("FX_SANITIZE_DOWNLOADS", refObj);
      },
    },

    sessions: {
      async clear(range) {
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_SESSIONS", refObj);
        await clearData(range, Ci.nsIClearDataService.CLEAR_AUTH_TOKENS |
                               Ci.nsIClearDataService.CLEAR_AUTH_CACHE);
        TelemetryStopwatch.finish("FX_SANITIZE_SESSIONS", refObj);
      },
    },

    siteSettings: {
      async clear(range) {
        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_SITESETTINGS", refObj);
        await clearData(range, Ci.nsIClearDataService.CLEAR_PERMISSIONS |
                               Ci.nsIClearDataService.CLEAR_CONTENT_PREFERENCES |
                               Ci.nsIClearDataService.CLEAR_DOM_PUSH_NOTIFICATIONS |
                               Ci.nsIClearDataService.CLEAR_SECURITY_SETTINGS);
        TelemetryStopwatch.finish("FX_SANITIZE_SITESETTINGS", refObj);
      },
    },

    openWindows: {
      _canCloseWindow(win) {
        if (win.CanCloseWindow()) {
          // We already showed PermitUnload for the window, so let's
          // make sure we don't do it again when we actually close the
          // window.
          win.skipNextCanClose = true;
          return true;
        }
        return false;
      },
      _resetAllWindowClosures(windowList) {
        for (let win of windowList) {
          win.skipNextCanClose = false;
        }
      },
      async clear(range, privateStateForNewWindow = "non-private") {
        // NB: this closes all *browser* windows, not other windows like the library, about window,
        // browser console, etc.

        // Keep track of the time in case we get stuck in la-la-land because of onbeforeunload
        // dialogs
        let existingWindow = Services.appShell.hiddenDOMWindow;
        let startDate = existingWindow.performance.now();

        // First check if all these windows are OK with being closed:
        let windowList = [];
        for (let someWin of Services.wm.getEnumerator("navigator:browser")) {
          windowList.push(someWin);
          // If someone says "no" to a beforeunload prompt, we abort here:
          if (!this._canCloseWindow(someWin)) {
            this._resetAllWindowClosures(windowList);
            throw new Error("Sanitize could not close windows: cancelled by user");
          }

          // ...however, beforeunload prompts spin the event loop, and so the code here won't get
          // hit until the prompt has been dismissed. If more than 1 minute has elapsed since we
          // started prompting, stop, because the user might not even remember initiating the
          // 'forget', and the timespans will be all wrong by now anyway:
          if (existingWindow.performance.now() > (startDate + 60 * 1000)) {
            this._resetAllWindowClosures(windowList);
            throw new Error("Sanitize could not close windows: timeout");
          }
        }

        // If/once we get here, we should actually be able to close all windows.

        let refObj = {};
        TelemetryStopwatch.start("FX_SANITIZE_OPENWINDOWS", refObj);

        // First create a new window. We do this first so that on non-mac, we don't
        // accidentally close the app by closing all the windows.
        let handler = Cc["@mozilla.org/browser/clh;1"].getService(Ci.nsIBrowserHandler);
        let defaultArgs = handler.defaultArgs;
        let features = "chrome,all,dialog=no," + privateStateForNewWindow;
        let newWindow = existingWindow.openDialog(AppConstants.BROWSER_CHROME_URL, "_blank",
                                                  features, defaultArgs);

        let onFullScreen = null;
        if (AppConstants.platform == "macosx") {
          onFullScreen = function(e) {
            newWindow.removeEventListener("fullscreen", onFullScreen);
            let docEl = newWindow.document.documentElement;
            let sizemode = docEl.getAttribute("sizemode");
            if (!newWindow.fullScreen && sizemode == "fullscreen") {
              docEl.setAttribute("sizemode", "normal");
              e.preventDefault();
              e.stopPropagation();
              return false;
            }
            return undefined;
          };
          newWindow.addEventListener("fullscreen", onFullScreen);
        }

        let promiseReady = new Promise(resolve => {
          // Window creation and destruction is asynchronous. We need to wait
          // until all existing windows are fully closed, and the new window is
          // fully open, before continuing. Otherwise the rest of the sanitizer
          // could run too early (and miss new cookies being set when a page
          // closes) and/or run too late (and not have a fully-formed window yet
          // in existence). See bug 1088137.
          let newWindowOpened = false;
          let onWindowOpened = function(subject, topic, data) {
            if (subject != newWindow)
              return;

            Services.obs.removeObserver(onWindowOpened, "browser-delayed-startup-finished");
            if (AppConstants.platform == "macosx") {
              newWindow.removeEventListener("fullscreen", onFullScreen);
            }
            newWindowOpened = true;
            // If we're the last thing to happen, invoke callback.
            if (numWindowsClosing == 0) {
              TelemetryStopwatch.finish("FX_SANITIZE_OPENWINDOWS", refObj);
              resolve();
            }
          };

          let numWindowsClosing = windowList.length;
          let onWindowClosed = function() {
            numWindowsClosing--;
            if (numWindowsClosing == 0) {
              Services.obs.removeObserver(onWindowClosed, "xul-window-destroyed");
              // If we're the last thing to happen, invoke callback.
              if (newWindowOpened) {
                TelemetryStopwatch.finish("FX_SANITIZE_OPENWINDOWS", refObj);
                resolve();
              }
            }
          };
          Services.obs.addObserver(onWindowOpened, "browser-delayed-startup-finished");
          Services.obs.addObserver(onWindowClosed, "xul-window-destroyed");
        });

        // Start the process of closing windows
        while (windowList.length) {
          windowList.pop().close();
        }
        newWindow.focus();
        await promiseReady;
      },
    },

    pluginData: {
      async clear(range) {
        await clearData(range, Ci.nsIClearDataService.CLEAR_PLUGIN_DATA);
      },
    },
  },
};

async function sanitizeInternal(items, aItemsToClear, progress, options = {}) {
  let { ignoreTimespan = true, range } = options;
  let seenError = false;
  // Shallow copy the array, as we are going to modify it in place later.
  if (!Array.isArray(aItemsToClear))
    throw new Error("Must pass an array of items to clear.");
  let itemsToClear = [...aItemsToClear];

  // Store the list of items to clear, in case we are killed before we
  // get a chance to complete.
  let uid = gPendingSanitizationSerial++;
  // Shutdown sanitization is managed outside.
  if (!progress.isShutdown)
    addPendingSanitization(uid, itemsToClear, options);

  // Store the list of items to clear, for debugging/forensics purposes
  for (let k of itemsToClear) {
    progress[k] = "ready";
  }

  // Ensure open windows get cleared first, if they're in our list, so that
  // they don't stick around in the recently closed windows list, and so we
  // can cancel the whole thing if the user selects to keep a window open
  // from a beforeunload prompt.
  let openWindowsIndex = itemsToClear.indexOf("openWindows");
  if (openWindowsIndex != -1) {
    itemsToClear.splice(openWindowsIndex, 1);
    await items.openWindows.clear(null, options);
    progress.openWindows = "cleared";
  }

  // If we ignore timespan, clear everything,
  // otherwise, pick a range.
  if (!ignoreTimespan && !range) {
    range = Sanitizer.getClearRange();
  }

  // For performance reasons we start all the clear tasks at once, then wait
  // for their promises later.
  // Some of the clear() calls may raise exceptions (for example bug 265028),
  // we catch and store them, but continue to sanitize as much as possible.
  // Callers should check returned errors and give user feedback
  // about items that could not be sanitized
  let refObj = {};
  TelemetryStopwatch.start("FX_SANITIZE_TOTAL", refObj);

  let annotateError = (name, ex) => {
    progress[name] = "failed";
    seenError = true;
    console.error("Error sanitizing " + name, ex);
  };

  // Array of objects in form { name, promise }.
  // `name` is the item's name and `promise` may be a promise, if the
  // sanitization is asynchronous, or the function return value, otherwise.
  let handles = [];
  for (let name of itemsToClear) {
    let item = items[name];
    try {
      // Catch errors here, so later we can just loop through these.
      handles.push({ name,
                     promise: item.clear(range, options)
                                  .then(() => progress[name] = "cleared",
                                        ex => annotateError(name, ex)),
                   });
    } catch (ex) {
      annotateError(name, ex);
    }
  }
  for (let handle of handles) {
    progress[handle.name] = "blocking";
    await handle.promise;
  }

  // Sanitization is complete.
  TelemetryStopwatch.finish("FX_SANITIZE_TOTAL", refObj);
  if (!progress.isShutdown)
    removePendingSanitization(uid);
  progress = {};
  if (seenError) {
    throw new Error("Error sanitizing");
  }
}

// This is an helper that retrieves the principals with site data just once
// and only when needed.
class PrincipalsCollector {
  constructor() {
    this.principals = null;
  }

  async getAllPrincipals(progress) {
    if (this.principals == null) {
      // Here is the list of principals with site data.
      progress.advancement = "get-principals";
      this.principals = await this.getAllPrincipalsInternal(progress);
    }

    return this.principals;
  }

  async getAllPrincipalsInternal(progress) {
    progress.step = "principals-quota-manager";
    let principals = await new Promise(resolve => {
      quotaManagerService.getUsage(request => {
        progress.step = "principals-quota-manager-getUsage";
        if (request.resultCode != Cr.NS_OK) {
          // We are probably shutting down. We don't want to propagate the
          // error, rejecting the promise.
          resolve([]);
          return;
        }

        let list = [];
        for (let item of request.result) {
          let principal = Services.scriptSecurityManager.createCodebasePrincipalFromOrigin(item.origin);
          let uri = principal.URI;
          if (isSupportedURI(uri)) {
            list.push(principal);
          }
        }

        progress.step = "principals-quota-manager-completed";
        resolve(list);
      });
    }).catch(ex => {
      Cu.reportError("QuotaManagerService promise failed: " + ex);
      return [];
    });

    progress.step = "principals-service-workers";
    let serviceWorkers = serviceWorkerManager.getAllRegistrations();
    for (let i = 0; i < serviceWorkers.length; i++) {
      let sw = serviceWorkers.queryElementAt(i, Ci.nsIServiceWorkerRegistrationInfo);
      // We don't need to check the scheme. SW are just exposed to http/https URLs.
      principals.push(sw.principal);
    }

    // Let's take the list of unique hosts+OA from cookies.
    progress.step = "principals-cookies";
    let enumerator = Services.cookies.enumerator;
    let hosts = new Set();
    for (let cookie of enumerator) {
      hosts.add(cookie.rawHost + ChromeUtils.originAttributesToSuffix(cookie.originAttributes));
    }

    progress.step = "principals-host-cookie";
    hosts.forEach(host => {
      // Cookies and permissions are handled by origin/host. Doesn't matter if we
      // use http: or https: schema here.
      principals.push(
        Services.scriptSecurityManager.createCodebasePrincipalFromOrigin("https://" + host));
    });

    progress.step = "total-principals:" + principals.length;
    return principals;
  }
}

async function sanitizeOnShutdown(progress) {
  log("Sanitizing on shutdown");

  if (Sanitizer.shouldSanitizeOnShutdown) {
    // Need to sanitize upon shutdown
    progress.advancement = "shutdown-cleaner";
    let itemsToClear = getItemsToClearFromPrefBranch(Sanitizer.PREF_SHUTDOWN_BRANCH);
    await Sanitizer.sanitize(itemsToClear, { progress });
  }

  let principalsCollector = new PrincipalsCollector();

  // Clear out QuotaManager storage for principals that have been marked as
  // session only.  The cookie service has special logic that avoids writing
  // such cookies to disk, but QuotaManager always touches disk, so we need to
  // wipe the data on shutdown (or startup if we failed to wipe it at
  // shutdown).  (Note that some session cookies do survive Firefox restarts
  // because the Session Store that remembers your tabs between sessions takes
  // on the responsibility for persisting them through restarts.)
  //
  // The default value is determined by the "Browser Privacy" preference tab's
  // "Cookies and Site Data" "Accept cookies and site data from websites...Keep
  // until" setting.  The default is "They expire" (ACCEPT_NORMALLY), but it
  // can also be set to "PRODUCT is closed" (ACCEPT_SESSION).  A permission can
  // also be explicitly set on a per-origin basis from the Page Info's "Set
  // Cookies" row.
  //
  // We can think of there being two groups that might need to be wiped.
  // First, when the default is set to ACCEPT_SESSION, then all origins that
  // use QuotaManager storage but don't have a specific permission set to
  // ACCEPT_NORMALLY need to be wiped.  Second, the set of origins that have
  // the permission explicitly set to ACCEPT_SESSION need to be wiped.  There
  // are also other ways to think about and accomplish this, but this is what
  // the logic below currently does!
  if (Services.prefs.getIntPref(PREF_COOKIE_LIFETIME,
                                Ci.nsICookieService.ACCEPT_NORMALLY) == Ci.nsICookieService.ACCEPT_SESSION) {
    log("Session-only configuration detected");
    progress.advancement = "session-only";

    let principals = await principalsCollector.getAllPrincipals(progress);
    await maybeSanitizeSessionPrincipals(progress, principals);
    return;
  }

  progress.advancement = "session-permission";

  // Let's see if we have to forget some particular site.
  for (let permission of Services.perms.enumerator) {
    if (permission.type != "cookie" ||
        permission.capability != Ci.nsICookiePermission.ACCESS_SESSION) {
      continue;
    }

    // We consider just permissions set for http, https and file URLs.
    if (!isSupportedURI(permission.principal.URI)) {
      continue;
    }

    log("Custom session cookie permission detected for: " + permission.principal.URI.spec);

    // We use just the URI here, because permissions ignore OriginAttributes.
    let principals = await principalsCollector.getAllPrincipals(progress);
    let selectedPrincipals = extractMatchingPrincipals(principals, permission.principal.URI);
    await maybeSanitizeSessionPrincipals(progress, selectedPrincipals);
  }

  if (Sanitizer.shouldSanitizeNewTabContainer) {
    progress.advancement = "newtab-segregation";
    sanitizeNewTabSegregation();
    removePendingSanitization("newtab-container");
  }

  if (Sanitizer.shouldSanitizeOnShutdown) {
    // We didn't crash during shutdown sanitization, so annotate it to avoid
    // sanitizing again on startup.
    removePendingSanitization("shutdown");
    Services.prefs.savePrefFile(null);
  }

  progress.advancement = "done";
}

// Extracts the principals matching matchUri as root domain.
function extractMatchingPrincipals(principals, matchUri) {
  return principals.filter(principal => {
    return Services.eTLD.hasRootDomain(matchUri.host, principal.URI.host);
  });
}

// This method receives a list of principals and it checks if some of them or
// some of their sub-domain need to be sanitize.
async function maybeSanitizeSessionPrincipals(progress, principals) {
  log("Sanitizing " + principals.length + " principals");

  let promises = [];

  principals.forEach(principal => {
    progress.step = "checking-principal";
    let cookieAllowed = cookiesAllowedForDomainOrSubDomain(principal);
    progress.step = "principal-checked:" + cookieAllowed;

    if (!cookieAllowed) {
      promises.push(sanitizeSessionPrincipal(progress, principal));
    }
  });

  progress.step = "promises:" + promises.length;
  return Promise.all(promises);
}

function cookiesAllowedForDomainOrSubDomain(principal) {
  log("Checking principal: " + principal.URI.spec);

  // If we have the 'cookie' permission for this principal, let's return
  // immediately.
  let p = Services.perms.testPermissionFromPrincipal(principal, "cookie");
  if (p == Ci.nsICookiePermission.ACCESS_ALLOW) {
    log("Cookie allowed!");
    return true;
  }

  if (p == Ci.nsICookiePermission.ACCESS_DENY ||
      p == Ci.nsICookiePermission.ACCESS_SESSION) {
    log("Cookie denied or session!");
    return false;
  }

  // This is an old profile with unsupported permission values
  if (p != Ci.nsICookiePermission.ACCESS_DEFAULT) {
    log("Not supported cookie permission: " + p);
    return false;
  }

  for (let perm of Services.perms.enumerator) {
    if (perm.type != "cookie") {
      continue;
    }

    // We consider just permissions set for http, https and file URLs.
    if (!isSupportedURI(perm.principal.URI)) {
      continue;
    }

    // We don't care about scheme, port, and anything else.
    if (Services.eTLD.hasRootDomain(perm.principal.URI.host,
                                    principal.URI.host)) {
      log("Recursive cookie check on principal: " + perm.principal.URI.spec);
      return cookiesAllowedForDomainOrSubDomain(perm.principal);
    }
  }

  log("Cookie not allowed.");
  return false;
}

async function sanitizeSessionPrincipal(progress, principal) {
  log("Sanitizing principal: " + principal.URI.spec);

  progress.step = "sanitizing";
  await new Promise(resolve => {
    Services.clearData.deleteDataFromPrincipal(principal, true /* user request */,
                                               Ci.nsIClearDataService.CLEAR_DOM_STORAGES |
                                               Ci.nsIClearDataService.CLEAR_COOKIES,
                                               resolve);
  });
  progress.step = "sanitized";
}

function sanitizeNewTabSegregation() {
  let identity = ContextualIdentityService.getPrivateIdentity("userContextIdInternal.thumbnail");
  if (identity) {
    Services.clearData.deleteDataFromOriginAttributesPattern({ userContextId: identity.userContextId });
  }
}

/**
 * Gets an array of items to clear from the given pref branch.
 * @param branch The pref branch to fetch.
 * @return Array of items to clear
 */
function getItemsToClearFromPrefBranch(branch) {
  branch = Services.prefs.getBranch(branch);
  return Object.keys(Sanitizer.items).filter(itemName => {
    try {
      return branch.getBoolPref(itemName);
    } catch (ex) {
      return false;
    }
  });
}

/**
 * These functions are used to track pending sanitization on the next startup
 * in case of a crash before a sanitization could happen.
 * @param id A unique id identifying the sanitization
 * @param itemsToClear The items to clear
 * @param options The Sanitize options
 */
function addPendingSanitization(id, itemsToClear, options) {
  let pendingSanitizations = safeGetPendingSanitizations();
  pendingSanitizations.push({id, itemsToClear, options});
  Services.prefs.setStringPref(Sanitizer.PREF_PENDING_SANITIZATIONS,
                               JSON.stringify(pendingSanitizations));
}

function removePendingSanitization(id) {
  let pendingSanitizations = safeGetPendingSanitizations();
  let i = pendingSanitizations.findIndex(s => s.id == id);
  let [s] = pendingSanitizations.splice(i, 1);
  Services.prefs.setStringPref(Sanitizer.PREF_PENDING_SANITIZATIONS,
    JSON.stringify(pendingSanitizations));
  return s;
}

function getAndClearPendingSanitizations() {
  let pendingSanitizations = safeGetPendingSanitizations();
  if (pendingSanitizations.length)
    Services.prefs.clearUserPref(Sanitizer.PREF_PENDING_SANITIZATIONS);
  return pendingSanitizations;
}

function safeGetPendingSanitizations() {
  try {
    return JSON.parse(
      Services.prefs.getStringPref(Sanitizer.PREF_PENDING_SANITIZATIONS, "[]"));
  } catch (ex) {
    Cu.reportError("Invalid JSON value for pending sanitizations: " + ex);
    return [];
  }
}

async function clearData(range, flags) {
  if (range) {
    await new Promise(resolve => {
      Services.clearData.deleteDataInTimeRange(range[0], range[1], true /* user request */,
                                               flags, resolve);
    });
  } else {
    await new Promise(resolve => {
      Services.clearData.deleteData(flags, resolve);
    });
  }
}

function isSupportedURI(uri) {
  return uri.scheme == "http" ||
         uri.scheme == "https" ||
         uri.scheme == "file";
}