Device can be tricked into exposing mtp service without being unlocked first

[Michael Terry]

Steps to reproduce:

- Boot your phone up (notice mtp is not accessible)
- Start to make an emergency call (notice mtp is not accessible)
- Cancel emergency call and go back to greeter (notice mtp IS accessible)

That's bad.

This happens because mtp-server pays attention to the greeter saying it's active over DBus. And the first time it says it's active, mtp-server makes itself available.

I believe the greeter has a bug where it briefly says it's inactive when transitioning between emergency dialer and the greeter. We should close that gap (once I confirm it exists).

[Marc Deslauriers (mdeslaur)]

This is CVE-2015-7946

[Launchpad Janitor (janitor)]

This bug was fixed in the package unity8 - 8.11+16.04.20160111.1-0ubuntu1

---------------
unity8 (8.11+16.04.20160111.1-0ubuntu1) xenial; urgency=medium

  [ Albert Astals Cid ]
  * Clear fake item icon name as soon as it goes invisible (LP:
    #1531172)
  * Fix LVWPH test failing on Xenial (Qt 5.5)
  * Fix dragging so that test passes on Xenial
  * Fix focus on the dash page header text field with new SDK (LP:
    #1528178)
  * Make the card creator test pass again
  * Quit the dash communicator thread before destroying it (LP:
    #1508485)
  * Remove duplicated override_dh_auto_clean
  * SDK changed the name they give to the buttons, follow

  [ Andrea Cimitan ]
  * Fix a broken binding

  [ CI Train Bot ]
  * Resync trunk.
  * Update translation template

  [ Daniel d'Andrada ]
  * Have "make tryFoo" work with Qt 5.5
  * Make DragHandle tests run again.

  [ Lukáš Tinkl ]
  * Fix dismissing the launcher when clicking/tapping outside (LP:
    #1531339, #1530940)
  * Fix panel drop shadow and click-to-focus of maximized apps (LP:
    #1531854)
  * Fix wifi access point indicator items signal strength icon on
    desktop

  [ Michael Terry ]
  * Guard against a couple odd timing scenarios for the too-many-failed-
    login-attempts lockout screen.
  * Skip the wizard's password screens if there is already a password
    set by other means. (LP: #1531268)
  * Stop the emergency dialer from accidentally exposing the mtp
    service. (LP: #1525981)

  [ Michael Zanetti ]
  * Make sure the triangle of the quicklist is in bounds (LP: #1531340)

  [ Pawel Stolowski ]
  * Changes 'shareData' and 'contentType' attributes to 'share-data' and
    'content-type', to match existing naming schema.

 -- Michał Sawicz <email address hidden> Mon, 11 Jan 2016 17:38:49 +0000