tree 60c22742e4653106e93c886e2aa003c3ae0cb0c2
parent 68b9fb10ae1bf1491c8dc6d854be900e62ebc090
author Barani Muthukumaran <quic_bmuthuku@quicinc.com> 1580764005 -0800
committer Paul Crowley <paulcrowley@google.com> 1581546386 -0800

vold: Support Storage keys for FBE

To prevent keys from being compromised if an attacker
acquires read access to kernel memory, some inline
encryption hardware supports protecting the keys in
hardware without software having access to or the
ability to set the plaintext keys.  Instead, software
only sees "wrapped keys", which may differ on every boot.

'wrappedkey_v0' fileencryption flag is used to denote
that the device supports inline encryption hardware that
supports this feature. On such devices keymaster is used
to generate keys with STORAGE_KEY tag and export a
per-boot ephemerally wrapped storage key to install it in
the kernel.

The wrapped key framework in the linux kernel ensures the
wrapped key is provided to the inline encryption hardware
where it is unwrapped and the file contents key is derived
to encrypt contents without revealing the plaintext key in
the clear.

Test: FBE validation with Fscrypt v2 + inline crypt + wrapped
key changes kernel.

Bug: 147733587

Change-Id: I1f0de61b56534ec1df9baef075acb74bacd00758