[avb] Add library libpvmfw_avb_nostd and test it in presubmit
Bug: 237373557
Test: m pvmfw_img && atest libpvmfw_avb.test
Change-Id: I80c19d4081b97ae57d0b50c04d3368b417a6411a
diff --git a/pvmfw/avb/src/lib.rs b/pvmfw/avb/src/lib.rs
new file mode 100644
index 0000000..eb1f918
--- /dev/null
+++ b/pvmfw/avb/src/lib.rs
@@ -0,0 +1,21 @@
+// Copyright 2022, The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! A library implementing the payload verification for pvmfw with libavb
+
+#![cfg_attr(not(test), no_std)]
+
+mod verify;
+
+pub use verify::{verify_payload, AvbImageVerifyError};
diff --git a/pvmfw/avb/src/verify.rs b/pvmfw/avb/src/verify.rs
new file mode 100644
index 0000000..7f3ba3d
--- /dev/null
+++ b/pvmfw/avb/src/verify.rs
@@ -0,0 +1,112 @@
+// Copyright 2022, The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! This module handles the pvmfw payload verification.
+
+use avb_bindgen::AvbSlotVerifyResult;
+use core::fmt;
+
+/// Error code from AVB image verification.
+#[derive(Clone, Debug)]
+pub enum AvbImageVerifyError {
+ /// AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT
+ InvalidArgument,
+ /// AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA
+ InvalidMetadata,
+ /// AVB_SLOT_VERIFY_RESULT_ERROR_IO
+ Io,
+ /// AVB_SLOT_VERIFY_RESULT_ERROR_OOM
+ Oom,
+ /// AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED
+ PublicKeyRejected,
+ /// AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX
+ RollbackIndex,
+ /// AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION
+ UnsupportedVersion,
+ /// AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION
+ Verification,
+}
+
+impl fmt::Display for AvbImageVerifyError {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ match self {
+ Self::InvalidArgument => write!(f, "Invalid parameters."),
+ Self::InvalidMetadata => write!(f, "Invalid metadata."),
+ Self::Io => write!(f, "I/O error while trying to load data or get a rollback index."),
+ Self::Oom => write!(f, "Unable to allocate memory."),
+ Self::PublicKeyRejected => write!(f, "Public key rejected or data not signed."),
+ Self::RollbackIndex => write!(f, "Rollback index is less than its stored value."),
+ Self::UnsupportedVersion => write!(
+ f,
+ "Some of the metadata requires a newer version of libavb than what is in use."
+ ),
+ Self::Verification => write!(f, "Data does not verify."),
+ }
+ }
+}
+
+fn to_avb_verify_result(result: AvbSlotVerifyResult) -> Result<(), AvbImageVerifyError> {
+ match result {
+ AvbSlotVerifyResult::AVB_SLOT_VERIFY_RESULT_OK => Ok(()),
+ AvbSlotVerifyResult::AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT => {
+ Err(AvbImageVerifyError::InvalidArgument)
+ }
+ AvbSlotVerifyResult::AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA => {
+ Err(AvbImageVerifyError::InvalidMetadata)
+ }
+ AvbSlotVerifyResult::AVB_SLOT_VERIFY_RESULT_ERROR_IO => Err(AvbImageVerifyError::Io),
+ AvbSlotVerifyResult::AVB_SLOT_VERIFY_RESULT_ERROR_OOM => Err(AvbImageVerifyError::Oom),
+ AvbSlotVerifyResult::AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED => {
+ Err(AvbImageVerifyError::PublicKeyRejected)
+ }
+ AvbSlotVerifyResult::AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX => {
+ Err(AvbImageVerifyError::RollbackIndex)
+ }
+ AvbSlotVerifyResult::AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION => {
+ Err(AvbImageVerifyError::UnsupportedVersion)
+ }
+ AvbSlotVerifyResult::AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION => {
+ Err(AvbImageVerifyError::Verification)
+ }
+ }
+}
+
+/// Verifies the payload (signed kernel + initrd) against the trusted public key.
+pub fn verify_payload(_public_key: &[u8]) -> Result<(), AvbImageVerifyError> {
+ // TODO(b/256148034): Verify the kernel image with avb_slot_verify()
+ // let result = unsafe {
+ // avb_slot_verify(
+ // &mut avb_ops,
+ // requested_partitions.as_ptr(),
+ // ab_suffix.as_ptr(),
+ // flags,
+ // hashtree_error_mode,
+ // null_mut(),
+ // )
+ // };
+ let result = AvbSlotVerifyResult::AVB_SLOT_VERIFY_RESULT_OK;
+ to_avb_verify_result(result)
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ // TODO(b/256148034): Test verification succeeds with valid payload later.
+ #[test]
+ fn verification_succeeds_with_placeholder_input() {
+ let fake_public_key = [0u8; 2];
+ assert!(verify_payload(&fake_public_key).is_ok());
+ }
+}