Support cross-UID access from AndroidKeyStore.
This is meant for exposing the pre-existing cross-UID access to keys
backed by the keystore service via higher-level JCA API. For example,
this lets system_server use Wi-Fi or VPN UID keys via JCA API.
To obtain a JCA AndroidKeyStore KeyStore for another UID, use the
hidden system API AndroidKeyStoreProvider.getKeyStoreForUid(uid).
To generate a key owned by another UID, invoke setUid(uid) on
KeyGenParameterSpec.Builder.
This CL does not change the security policy, such as which UID can
access/modify which UIDs' keys. The policy is that only certain system
UIDs are permitted to access keys of certain other system UIDs.
Bug: 23978113
Change-Id: Ie381530f41dc41c50d52f675fb9e68bc87c006de
27 files changed