[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/TEST_MAPPING b/TEST_MAPPING
index dd81738..321dbf4 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -58,6 +58,9 @@
       "path": "packages/modules/Virtualization/authfs"
     },
     {
+      "path": "packages/modules/Virtualization/pvmfw"
+    },
+    {
       "path": "packages/modules/Virtualization/rialto"
     },
     {
diff --git a/libs/avb/Android.bp b/libs/avb/Android.bp
index 8bac942..436f672 100644
--- a/libs/avb/Android.bp
+++ b/libs/avb/Android.bp
@@ -37,18 +37,3 @@
     clippy_lints: "none",
     lints: "none",
 }
-
-rust_library_rlib {
-    name: "libavb_nostd",
-    crate_name: "avb",
-    srcs: ["src/lib.rs"],
-    no_stdlibs: true,
-    prefer_rlib: true,
-    stdlibs: [
-        "libcore.rust_sysroot",
-    ],
-    rustlibs: [
-        "libavb_bindgen",
-        "liblog_rust_nostd",
-    ],
-}
diff --git a/pvmfw/Android.bp b/pvmfw/Android.bp
index 318c7fe..5ed7bd6 100644
--- a/pvmfw/Android.bp
+++ b/pvmfw/Android.bp
@@ -13,11 +13,11 @@
     ],
     rustlibs: [
         "libaarch64_paging",
-        "libavb_nostd",
         "libbuddy_system_allocator",
         "libdice_nostd",
         "liblibfdt",
         "liblog_rust_nostd",
+        "libpvmfw_avb_nostd",
         "libpvmfw_embedded_key",
         "libtinyvec_nostd",
         "libvirtio_drivers",
diff --git a/pvmfw/TEST_MAPPING b/pvmfw/TEST_MAPPING
new file mode 100644
index 0000000..8a2d352
--- /dev/null
+++ b/pvmfw/TEST_MAPPING
@@ -0,0 +1,7 @@
+{
+  "avf-presubmit" : [
+    {
+      "name" : "libpvmfw_avb.test"
+    }
+  ]
+}
\ No newline at end of file
diff --git a/pvmfw/avb/Android.bp b/pvmfw/avb/Android.bp
new file mode 100644
index 0000000..65259a5
--- /dev/null
+++ b/pvmfw/avb/Android.bp
@@ -0,0 +1,28 @@
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+rust_defaults {
+    name: "libpvmfw_avb_nostd_defaults",
+    crate_name: "pvmfw_avb",
+    srcs: ["src/lib.rs"],
+    prefer_rlib: true,
+    rustlibs: [
+        "libavb_bindgen",
+    ],
+}
+
+rust_library_rlib {
+    name: "libpvmfw_avb_nostd",
+    defaults: ["libpvmfw_avb_nostd_defaults"],
+    no_stdlibs: true,
+    stdlibs: [
+        "libcore.rust_sysroot",
+    ],
+}
+
+rust_test {
+    name: "libpvmfw_avb.test",
+    defaults: ["libpvmfw_avb_nostd_defaults"],
+    test_suites: ["general-tests"],
+}
diff --git a/libs/avb/src/lib.rs b/pvmfw/avb/src/lib.rs
similarity index 77%
rename from libs/avb/src/lib.rs
rename to pvmfw/avb/src/lib.rs
index 21b7d2a..eb1f918 100644
--- a/libs/avb/src/lib.rs
+++ b/pvmfw/avb/src/lib.rs
@@ -12,12 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! This module regroups the rust API for libavb.
+//! A library implementing the payload verification for pvmfw with libavb
 
-#![no_std]
+#![cfg_attr(not(test), no_std)]
 
-extern crate alloc;
+mod verify;
 
-mod ops;
-
-pub use ops::{verify_image, AvbImageVerifyError};
+pub use verify::{verify_payload, AvbImageVerifyError};
diff --git a/libs/avb/src/ops.rs b/pvmfw/avb/src/verify.rs
similarity index 60%
rename from libs/avb/src/ops.rs
rename to pvmfw/avb/src/verify.rs
index 8eb67f4..7f3ba3d 100644
--- a/libs/avb/src/ops.rs
+++ b/pvmfw/avb/src/verify.rs
@@ -12,20 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! This module regroups methods related to AvbOps.
+//! This module handles the pvmfw payload verification.
 
-#![warn(unsafe_op_in_unsafe_fn)]
-// TODO(b/256148034): Remove this when the feature is code complete.
-#![allow(dead_code)]
-#![allow(unused_imports)]
-
-use alloc::ffi::CString;
-use avb_bindgen::{avb_slot_verify, AvbHashtreeErrorMode, AvbSlotVerifyFlags, AvbSlotVerifyResult};
+use avb_bindgen::AvbSlotVerifyResult;
 use core::fmt;
-use log::debug;
 
 /// Error code from AVB image verification.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Debug)]
 pub enum AvbImageVerifyError {
     /// AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT
     InvalidArgument,
@@ -45,6 +38,24 @@
     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(()),
@@ -71,63 +82,31 @@
     }
 }
 
-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."),
-        }
-    }
+/// 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)
 }
 
-/// 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> {
-    // TODO(b/256148034): Call verify_slot() from pvmfw.
-    AvbOps::new().verify_slot()
-}
+#[cfg(test)]
+mod tests {
+    use super::*;
 
-/// 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_slot(&mut self) -> Result<(), AvbImageVerifyError> {
-        let flags = AvbSlotVerifyFlags::AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION;
-        let hashtree_error_mode = AvbHashtreeErrorMode::AVB_HASHTREE_ERROR_MODE_EIO;
-        debug!("flags: {:?}", flags);
-        debug!("hashtree_error_mode: {:?}", hashtree_error_mode);
-        // 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(),
-        //         flags,
-        //         hashtree_error_mode,
-        //         &image.as_ptr(),
-        //     )
-        // };
-        let result = AvbSlotVerifyResult::AVB_SLOT_VERIFY_RESULT_OK;
-        to_avb_verify_result(result)
+    // 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());
     }
 }
diff --git a/pvmfw/src/main.rs b/pvmfw/src/main.rs
index 79b6f57..039e674 100644
--- a/pvmfw/src/main.rs
+++ b/pvmfw/src/main.rs
@@ -38,10 +38,10 @@
     memory::MemoryTracker,
     pci::{allocate_all_virtio_bars, PciError, PciInfo, PciMemory32Allocator},
 };
-use ::avb::verify_image;
 use dice::bcc;
 use libfdt::Fdt;
 use log::{debug, error, info, trace};
+use pvmfw_avb::verify_payload;
 
 fn main(
     fdt: &Fdt,
@@ -71,7 +71,7 @@
     let mut pci_root = unsafe { pci_info.make_pci_root() };
     allocate_all_virtio_bars(&mut pci_root, &mut bar_allocator).map_err(handle_pci_error)?;
 
-    verify_image(signed_kernel, PUBLIC_KEY).map_err(|e| {
+    verify_payload(PUBLIC_KEY).map_err(|e| {
         error!("Failed to verify the payload: {e}");
         RebootReason::PayloadVerificationError
     })?;