This file attempts to list significant changes to the Rust reference implementation of KeyMint, where "significant" means things that are likely to affect vendors whose KeyMint implementations are based on this codebase.
sign_info field in kmr_ta::device::Implementation is now an Option, reflecting that batch attestation is now optional (devices can be RKP-only, as indicated by the remote_provisioning.tee.rkp_only system property).BootInfo structure passed to kmr_ta::KeyMintTa::set_boot_info() method did not make clear what the contents of the verified_boot_key field should be: the key itself, or a SHA-256 hash of the key. The KeyMint implementation has been modified to cope with either, using a SHA-256 hash in places where the value is externally visible (key attestations and root-of-trust transfer) when it appears that the full key has been provided. However, this requires that vendor implementations provide an implementation of the new Sha256 trait (from https://r.android.com/2786540). A sample implementation based on BoringSSL is available in boringssl/src/sha256.rs.hal_v2, hal_v3 etc. features are enabled in their build system (from https://r.android.com/2777607). Vendors using the Soong build system are unaffected (because the Soong targets have been updated).