tree 514f930addae708edfb05b471e8d60933c1d0d52
parent 4139a30ec532d0f0cfcd73cd929d30dc74e98597
author Tianjie Xu <xunchang@google.com> 1565119925 -0700
committer Bryan Ferris <bferris@google.com> 1581621398 +0000

Force off-device package installation with FUSE

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
Test: recovery_unit_test - no new failures

Change-Id: Ia5afd19854c3737110339fd59491b96708926ae5
Merged-In: I35119c2334895aa0ef4ed71b3ddd08f280c0c031