[avb] Define rust API for image verification and connect pvmfw

This CL
- defines the image verification rust API using avb_bindgen.
- defines the return error enum for the API.
- invokes the API from pvmfw.
- adds e2e test for the pvmfw run without error scenario.

Bug: 256148034
Test: atest MicrodroidHostTests
Change-Id: I272e9b8031e34137dca761b66ffabab264f055dd
diff --git a/libs/avb/src/avb_ops.rs b/libs/avb/src/avb_ops.rs
new file mode 100644
index 0000000..900e152
--- /dev/null
+++ b/libs/avb/src/avb_ops.rs
@@ -0,0 +1,153 @@
+// 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 regroups methods related to AvbOps.
+
+#![warn(unsafe_op_in_unsafe_fn)]
+// TODO(b/256148034): Remove this when the feature is code complete.
+#![allow(dead_code)]
+#![allow(unused_imports)]
+
+extern crate alloc;
+
+use alloc::ffi::CString;
+use avb_bindgen::{
+    avb_slot_verify, AvbHashtreeErrorMode_AVB_HASHTREE_ERROR_MODE_EIO,
+    AvbSlotVerifyFlags_AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION,
+    AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT,
+    AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA,
+    AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_IO,
+    AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_OOM,
+    AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED,
+    AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX,
+    AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION,
+    AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION,
+    AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_OK,
+};
+use core::fmt;
+use log::debug;
+
+/// Error code from AVB image verification.
+#[derive(Clone, Copy, Debug)]
+pub enum AvbImageVerifyError {
+    /// AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT
+    InvalidArgument,
+    /// AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA
+    InvalidMetadata,
+    /// AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_IO
+    Io,
+    /// AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_OOM
+    Oom,
+    /// AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED
+    PublicKeyRejected,
+    /// AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX
+    RollbackIndex,
+    /// AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION
+    UnsupportedVersion,
+    /// AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION
+    Verification,
+    /// Unknown error.
+    Unknown(u32),
+}
+
+fn to_avb_verify_result(result: u32) -> Result<(), AvbImageVerifyError> {
+    #[allow(non_upper_case_globals)]
+    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)
+        }
+        _ => Err(AvbImageVerifyError::Unknown(result)),
+    }
+}
+
+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,
+                "Everything is verified correctly out but the public key is not accepted. \
+                This includes the case where integrity data is 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."),
+            Self::Unknown(e) => write!(f, "Unknown avb_slot_verify error '{e}'"),
+        }
+    }
+}
+
+/// Verifies that for the given image:
+///  - The given public key is acceptable.
+///  - The VBMeta struct is valid.
+///  - The partitions of the image match the descriptors of the verified VBMeta struct.
+/// Returns Ok if everything is verified correctly and the public key is accepted.
+pub fn verify_image(image: &[u8], public_key: &[u8]) -> Result<(), AvbImageVerifyError> {
+    AvbOps::new().verify_image(image, public_key)
+}
+
+/// TODO(b/256148034): Make AvbOps a rust wrapper of avb_bindgen::AvbOps using foreign_types.
+struct AvbOps {}
+
+impl AvbOps {
+    fn new() -> Self {
+        AvbOps {}
+    }
+
+    fn verify_image(&self, image: &[u8], public_key: &[u8]) -> Result<(), AvbImageVerifyError> {
+        debug!("AVB image: addr={:?}, size={:#x} ({1})", image.as_ptr(), image.len());
+        debug!(
+            "AVB public key: addr={:?}, size={:#x} ({1})",
+            public_key.as_ptr(),
+            public_key.len()
+        );
+        // TODO(b/256148034): Verify the kernel image with avb_slot_verify()
+        // let result = unsafe {
+        //     avb_slot_verify(
+        //         self.as_ptr(),
+        //         requested_partitions.as_ptr(),
+        //         ab_suffix.as_ptr(),
+        //         AvbSlotVerifyFlags_AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION,
+        //         AvbHashtreeErrorMode_AVB_HASHTREE_ERROR_MODE_EIO,
+        //         &image.as_ptr(),
+        //     )
+        // };
+        let result = AvbSlotVerifyResult_AVB_SLOT_VERIFY_RESULT_OK;
+        to_avb_verify_result(result)
+    }
+}