Get critical parts of Tails audited

It would be nice to have to following parts or Tails audited:

• Audit whatever upgrade mechanism we replace the current Tails Upgrader with in the “Rethink upgrade/installation” effort (possible in ~2 years probably).
  - Audit the current implementation of Tails Upgrader. (Low prio since it will be obsoleted by the above point. ~1 kLoC of perl (but big parts are irrelevant since it is about generating IUKs.)
• Audit Tails Security Check (config/chroot_local-includes/usr/local/bin/tails-security-check, ~200 LoC.)
• Torification escapes for the Live user and other critical users
• Persistence
  - Arbitrary persistence by the Live user
  - Permissions of the device and data of the persistent device (Audit should be less than a day)
• Audit anonym’s Thunderbird auto-config patches (Javascript, 9 files changed, 254 insertions(+), 99 deletions(-).)

Related issues

• Related to #7465
• Related to #11051 (closed)

Original created by @jvoisin on 14508 (Redmine)