Security/Reviews/B2GUpdates: Difference between revisions

|SecReview feature goal=====FOTA Updates===

FOTA: Full over-the-air updates (i.e. Gonk/Drivers + Gecko + Gaia)

Purpose: Only for security bugs that can't be fixed in Gecko or Gaia. Ideally are never needed for shipping devices.

Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=778084

Wiki: https://wiki.mozilla.org/Gaia/System/Updates/Gonk

Frequency:  Immediate for critical security bugs. Quarterly for any non-critical  security bugs, if needed. If there are no bug fixes in a given quarter,  there is no quarterly update.

Integrity checking: Update packages will be signed .mar files (inside the mar file will be a zip file containing the update)

Update server(s): Currently AUS, production undecided???

Delivery: Updates will be provided over a private APN? (what about Wifi?)  

- Full flash of kernel & drivers etc

- android devices use recovery partition to achieve this

- our updates use this

- use google' update scripting language

- download update via existing firefox delivery mechanism (updater & mar)

- download a mar file (delivery & signing)

- updater runs to check signatures and update details

- sets up recovery partitioin (recovery commands)

- reboot in to recovery mode

- return back to normal mode

- status checking afterwards

- recovery mode also checks a signature of the oem key

Backup keys possible in mar file, but nbot in android

Purpose: Automatic updates of b2g "userspace" (gecko, built-in apps and dependencies; not third-party apps)  

Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=715816

Wiki: https://wiki.mozilla.org/Gaia/System/Updates/GeckoGaia

Frequency:

    - 42 weeks (ESR) > update cycle > 6 weeks (Firefox)

    - Current proposal is 18 weeks

Integrity checking:  

    - MAR Signing  (see https://bugzilla.mozilla.org/show_bug.cgi?id=783638)

    - Background information on the MAR file format: https://wiki.mozilla.org/Software_Update:MAR and how signing currently works before Bug 783638.

    - Gaia apps also signed as per packaged apps?

Update server(s): ?

Delivery: Updates will be provided over a private APN. (Wifi? Download to PC then USB update?)

Update flow: https://wiki.mozilla.org/images/4/46/SystemUpdates_Flow1.pdf

- very similar to firefox updates

- system partition is read-only

- updater mounts the partitition as read-write

- in case of error the device is rebooted

- UI is based on chromeEvents  

- system gaia apps hosted inside system partition

- size is important