tree cba636e772425eb8680c6b9356cc4a749425c232
parent 5afb9a1f11a3b3d8437e931d19d33c492106feac
author Tianjie Xu <xunchang@google.com> 1565119925 -0700
committer Tianjie Xu <xunchang@google.com> 1571250917 -0700

Force package installation with FUSE unless the package stores on device

The non-A/B package installation is subject to TOC/TOU flaw if the
attacker can switch the package in the middle of installation. And the
most pratical case is to store the package on an external device, e.g. a
sdcard, and swap the device in the middle.

To prevent that, we can adopt the same protection as used in sideloading
a package with FUSE. Specifically, when we install the package with FUSE,
we read the entire package to cryptographically verify its signature.
The hash for each transfer block is recorded in the memory (TOC), and
the subsequent reads (TOU) will be rejected upon dectecting a mismatch.

This CL forces the package installation with FUSE when the package stays
on a removable media.

Bug: 136498130
Test: Run bin/recovery --update_package with various paths;
and packages are installed from FUSE as expected

Change-Id: Ibc9b095036a2fa624e8edf6c347ed4f12aef072f