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Items to be reviewed:

Introduce Feature

Goal of Feature, what is trying to be achieved (problem solved, use cases, etc)

What solutions/approaches were considered other than the proposed solution?

  • the chrome approach - having two versions side by side and picking the latest one
    • this breaks things that rely on our installation directory being fixed
  • applying update on shutdown rather than start up - not planned currently

Why was this solution chosen?

  • works better
  • do not want to completely rearchitect how Firefox launches just to get silent updates

Any security threats already considered in the design and why?

  • not adding lots of new stuff
    • changes are to interactions between them
    • biggest change is in copying files

Threat Brainstorming

  • Race conditions during copying
    • we don't rename anything until we have two fully working versions
  • Folders/files being locked during rename/copying operations
  • dealing with issues of crash/fail during update
    • update.status is updated to track changes and monitor state
    • if a failure state is detected old directory is removed completely and created from scratch
  • Will Antivirus software freak out because of this relatively unusual behavior?
    • likely caught when landed in nightly if there is an issue
      • ZoneAlarm ForceField, TripWire
  • how do we verify we have a complete and proper copy?
    • status file = applying -> update is progressing, if halted in this state then we may have a failure we need to restart
    • if anything fails we bail out and write an error code to the file to notify the main firefox instance
    • only in success does update.status get changed to success

Conclusions / Action Items

  • [QA] If we have a comprehensive plan for "noisy" updates does that cover us for "silent" updates? Are there security "holes" we should be testing for?
    • I think a lot of the testing will have to be repeated for the silent case and the noisy case.
    • Failure of the silent case that should fall back to the noisy case needs to be tested