branches/web20/torbutton/en/design/FF35_AUDIT (c18f0dd52) - tor-webwml.git

FF35_AUDIT

First pass: Quick Review of Firefox Features
- Video Tag
  - Docs:
    - https://developer.mozilla.org/En/HTML/Element/Audio
    - https://developer.mozilla.org/En/HTML/Element/Video
    - https://developer.mozilla.org/En/HTML/Element/Source
    - https://developer.mozilla.org/En/Manipulating_video_using_canvas
    - https://developer.mozilla.org/En/nsIDOMHTMLMediaElement
    - https://developer.mozilla.org/En/Media_formats_supported_by_the_audio_and_video_elements
    - http://en.flossmanuals.net/TheoraCookbook
  - nsIContentPolicy is checked on load
  - Uses NSIChannels for initial load
  - Wrapped in nsHTMLMediaElement::mDecoder
    - is nsOggDecoder() or nsWaveDecoder()
    - liboggplay
  - Governed by media.* prefs
  - Preliminary audit shows they do not use the liboggplay tcp functions
- Geolocation
  - Wifi:
    - https://developer.mozilla.org/En/Monitoring_WiFi_access_points
    - Requires security policy to allow. Then still prompted
  - navigator.geolocation
    - Governed by geo.enabled
    - "2 week access token" is set
      - geo.wifi.access_token.. Clearing is prob a good idea
    - http://mxr.mozilla.org/mozilla1.9.1/source/dom/src/geolocation/NetworkGeolocationProvider.js
    - https://developer.mozilla.org/En/Using_geolocation
- DNS prefetching after toggle
  - prefetch pref? Always disable for now?
    - network.dns.disablePrefetch
    - Also disabled in netwerk/dns/src/nsDNSService2.cpp when manual proxies
      are set..
    - This should prevent prefetching of non-tor urls in tor mode..
    - But the reverse is unclear.
    - DocShell attribute!!1 YAY
      - http://www.oxymoronical.com/experiments/apidocs/interface/nsIDocShell
      - "Takes effect for the NEXT document loaded...."
        - Do we win this race? hrmm.. If we do, the tor->nontor direction
          should also be safe.
  - Content policy called?
    - No. See content/html/content/src/nsHTMLDNSPrefetch.cpp
- Storage
  - https://developer.mozilla.org/en/Storage
  - "It is available to trusted callers, meaning extensions and Firefox
    components only."
- New content policy
  - Content Security Policy. Addon-only
- "Offline resources"
  - https://developer.mozilla.org/en/Offline_resources_in_Firefox
  - https://developer.mozilla.org/en/nsIApplicationCache
  - browser.cache.offline.enable toggles
  - browser.cache.disk.enable does not apply. Seperate "device".
  - Does our normal cache clearing mechanism apply?
    - We call nsICacheService.evictEntries()
    - May need: nsOfflineCacheDevice::EvictEntries(NULL)
  - Code is smart enough to behave cleanly if we simply set
    browser.cache.offline.enable or enable private browsing.
- Mouse gesture and other new DOM events
- Fonts
  - Remote fonts obey content policy. Good.
  - XXX: Are they cached independent of regular cache? Prob not.
  - Hrmm can probe for installed fonts:
    http://remysharp.com/2008/07/08/how-to-detect-if-a-font-is-installed-only-using-javascript/
    http://www.lalit.org/lab/javascript-css-font-detect
    http://www.ajaxupdates.com/cssjavascript-font-detector/
    http://code.google.com/p/jquery-fontavailable/
- Drag and drop
  - https://developer.mozilla.org/En/DragDrop/Drag_and_Drop
  - https://developer.mozilla.org/En/DragDrop/Drag_Operations
  - https://developer.mozilla.org/En/DragDrop/Dragging_and_Dropping_Multiple_Items
  - https://developer.mozilla.org/En/DragDrop/Recommended_Drag_Types
  - https://developer.mozilla.org/En/DragDrop/DataTransfer
  - Should be no different than normal url handling..
- Local Storage
  - https://developer.mozilla.org/en/DOM/Storage#localStorage
  - Disabled by dom storage pref..
  - Private browsing mode has its own DB
    - Memory only?
  - Disk Avoidance of gStorage and local storage:
    - mSessionOnly set via nsDOMStorage::CanUseStorage()
      - Seems to be set to true if cookies are session-only or private
        browsing mode
        - Our cookies are NOT session-only with dual cookie jars
          - but this is ok if we clear the session storage..
            - XXX: Technically clearing session storage may break
              sites if cookies remain though
      - nsDOMStoragePersistentDB not used if mSessionOnly
  - Can clear with nsDOMStorage::ClearAll() or nsIDOMStorage2::clear()?
    - These only work for a particular storage. There's both global now
      and per-origin storage instances
    - Each docshell has tons of storages for each origin contained in it
    - Toggling dom.storage.enabled does not clear existing storage
    - Oh HOT! cookie-changed to clear cookies clears all storages!
      - happens for both ff3.0 and 3.5 in dom/src/storage/nsDOMStorage.cpp
  - Conclusion:
    - can safely enable dom storage
      - May have minor buggy usability issues unless we preserve it
        when user is preserving cookies..

Second Pass: Verification of all Torbutton Assumptions
- "Better privacy controls"
  - Basically UI stuff for prefs we set already
  - address bar search disable option is interesting, but not
    torbutton's job to toggle. Users will hate us.
- Private browsing
  - https://developer.mozilla.org/En/Supporting_private_browsing_mode
    - We should consider an option (off by default) to enable PBM during
      toggle
      - It is a good idea because it will let our users use DOM storage
        safely and also may cause their plugins and other addons to be
        safe
      - Doing it always will cause the user to lose fine-grained control
        of many settings
        - Also we'll need to prevent them from leaving without toggling tor
        - Stuff the emit does (grep for NS_PRIVATE_BROWSING_SWITCH_TOPIC and
          "private-browsing")
          - XXX:  clear mozilla.org/security/sdr;1. We should too! Wtf is it??
            - Neg. Best to let them handle this. Users will be annoyed
              at having to re-enter their passwords..
          - They also clear the console service..
          - Recommend watching private-browsing-cancel-vote and blocking if
            we are performing a db operation
            - Maybe we want to block transitions during our toggle for safety
          - XXX: They also clear general.open_location.last_url
          - XXX: mozilla.org/permissionmanager
          - XXX: mozilla.org/content-pref/service
          - XXX: Sets browser.zoom.siteSpecific to false
          - Interesting.. They clear their titles.. I wonder if some
            window managers log titles.. But that level of surveillance is
            unbeatable..
            - XXX: Unless there is some way for flash or script to read titles?
          - They empty the clipboard..
            - Can js access the clipboard?? ...
            - Yes, but needs special pref+confirmation box
              - http://www.dynamic-tools.net/toolbox/copyToClipboard/
          - They clear cache..
          - Cookies:
            - Use in-memory table that is different than their default
              - This could fuck up our cookie storage options
              - We could maybe prevent them from getting this
                event by wrapping nsCookieService::Observe(). Lullz..
          - NavHistory:
            - XXX: nsNavHistory::AutoCompleteFeedback() doesn't track
              awesomebar choices for feedback.. Is this done on disk?
            - Don't add history entries
            - We should block this observe event too if we can..
          - The session store stops storing tabs
            - We could block this observe
          - XXX: They expunge private temporary files on exit from PMB
            - This is not done normally until browser exit or
              "on-profile-change"
            - emits browser:purge-domain-data.. Mostly just for session
              editing it appears
            - Direct component query for pbs.privateBrowsingEnabled
              - This is where we have no ability to provide certain option
                control
              - browser.js seems to prevent user from allowing blocked
                popups?
              - Some items in some places context menu get blocked:
                - Can't delete items from history? placesContext_deleteHost
              - nsCookiePermission::InPrivateBrowsing() calls direct
                - but is irellevant
              - Form history cannot be saved while in PBM.. :(
              - User won't be prompted for adding login passwords..
              - Can't remember prefs on content types
              - Many components read this value upon init:
                - This fucks up our observer game if tor starts enabled
                - NavHistory and cookie and dl manager
                - We could just wrap the bool on startup and lie
                  and emit later... :/
                  - Or! emit an exit and an enter always at startup if tor is
                    enabled.
  - Read iSec report
  - Compare to Chrome
    - API use cases
- SessionStore
  - Has been reworked with observers and write methods. Should use those.
- security.enable_ssl2 to clear session id
  - Still cleared
- browser.sessionstore.max_tabs_undo
  - Yep.
- SafeBrowsing Update Key removed on cookie clear still?
  - Yep.
- Livemark updates have kill events now
- Test if nsICertStore is still buggy...

Third Pass: Exploit Auditing
- Remote fonts
- SVG with HTML
- Javascript threads+locking
- Ogg theora and vorbis codecs
- SQLite

- https://developer.mozilla.org/en/Firefox_3_for_developers

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