Merge "Rename bssl-ffi to bssl-sys" into main
diff --git a/microdroid/init.rc b/microdroid/init.rc
index 4cc0475..672f47d 100644
--- a/microdroid/init.rc
+++ b/microdroid/init.rc
@@ -94,9 +94,6 @@
 
     trigger post-fs-data
 
-    # Load persist properties and override properties (if enabled) from /data.
-    trigger load_persist_props_action
-
     trigger early-boot
     trigger boot
 
diff --git a/rialto/Android.bp b/rialto/Android.bp
index fcb1ce6..c102c89 100644
--- a/rialto/Android.bp
+++ b/rialto/Android.bp
@@ -142,7 +142,7 @@
         "libservice_vm_fake_chain",
         "libservice_vm_manager",
         "libvmclient",
-        "libx509_parser",
+        "libx509_cert_nostd",
     ],
     data: [
         ":rialto_unsigned",
diff --git a/rialto/tests/test.rs b/rialto/tests/test.rs
index 02a5a28..c918db5 100644
--- a/rialto/tests/test.rs
+++ b/rialto/tests/test.rs
@@ -40,12 +40,13 @@
 use std::io;
 use std::panic;
 use std::path::PathBuf;
+use std::str::FromStr;
 use vmclient::VmInstance;
-use x509_parser::{
-    certificate::X509Certificate,
-    der_parser::{ber::BerObject, der::parse_der, oid, oid::Oid},
-    prelude::FromDer,
-    x509::{AlgorithmIdentifier, SubjectPublicKeyInfo, X509Version},
+use x509_cert::{
+    certificate::{Certificate, Version},
+    der::{self, asn1, Decode, Encode},
+    name::Name,
+    spki::{AlgorithmIdentifier, ObjectIdentifier, SubjectPublicKeyInfo},
 };
 
 const UNSIGNED_RIALTO_PATH: &str = "/data/local/tmp/rialto_test/arm64/rialto_unsigned.bin";
@@ -136,7 +137,12 @@
     let dice_artifacts = fake_client_vm_dice_artifacts()?;
     let attestation_data = generate_attestation_key_and_csr(&CHALLENGE, &dice_artifacts)?;
     let cert_chain = fs::read(TEST_CERT_CHAIN_PATH)?;
-    let (remaining, cert) = X509Certificate::from_der(&cert_chain)?;
+    // The certificate chain contains several certificates, but we only need the first one.
+    // Parsing the data with trailing data always fails with a `TrailingData` error.
+    let cert_len: usize = match Certificate::from_der(&cert_chain).unwrap_err().kind() {
+        der::ErrorKind::TrailingData { decoded, .. } => decoded.try_into().unwrap(),
+        e => bail!("Unexpected error: {e}"),
+    };
 
     // Builds the mock parameters for the client VM attestation.
     // The `csr` and `remotely_provisioned_key_blob` parameters are extracted from the same
@@ -146,7 +152,7 @@
     let params = ClientVmAttestationParams {
         csr: attestation_data.csr.clone().into_cbor_vec()?,
         remotely_provisioned_key_blob: remotely_provisioned_key_pair.key_blob.to_vec(),
-        remotely_provisioned_cert: cert_chain[..(cert_chain.len() - remaining.len())].to_vec(),
+        remotely_provisioned_cert: cert_chain[..cert_len].to_vec(),
     };
     let request = Request::RequestClientVmAttestation(params);
 
@@ -162,7 +168,7 @@
                 &certificate,
                 &remotely_provisioned_key_pair.maced_public_key,
                 &attestation_data.csr,
-                &cert,
+                &Certificate::from_der(&cert_chain[..cert_len]).unwrap(),
             )?;
             Ok(())
         }
@@ -177,22 +183,26 @@
     }
 }
 
-fn check_vm_components(vm_components: &[BerObject]) -> Result<()> {
+fn check_vm_components(vm_components: &asn1::SequenceOf<asn1::Any, 4>) -> Result<()> {
     let expected_components = fake_sub_components();
     assert_eq!(expected_components.len(), vm_components.len());
-    for i in 0..expected_components.len() {
-        check_vm_component(&vm_components[i], &expected_components[i])?;
+    for (i, expected_component) in expected_components.iter().enumerate() {
+        check_vm_component(vm_components.get(i).unwrap(), expected_component)?;
     }
     Ok(())
 }
 
-fn check_vm_component(vm_component: &BerObject, expected_component: &SubComponent) -> Result<()> {
-    let vm_component = vm_component.as_sequence()?;
+fn check_vm_component(vm_component: &asn1::Any, expected_component: &SubComponent) -> Result<()> {
+    let vm_component = vm_component.decode_as::<asn1::SequenceOf<asn1::Any, 4>>().unwrap();
     assert_eq!(4, vm_component.len());
-    assert_eq!(expected_component.name, vm_component[0].as_str()?);
-    assert_eq!(expected_component.version, vm_component[1].as_u64()?);
-    assert_eq!(expected_component.code_hash, vm_component[2].as_slice()?);
-    assert_eq!(expected_component.authority_hash, vm_component[3].as_slice()?);
+    let name = vm_component.get(0).unwrap().decode_as::<asn1::Utf8StringRef>().unwrap();
+    assert_eq!(expected_component.name, name.as_ref());
+    let version = vm_component.get(1).unwrap().decode_as::<u64>().unwrap();
+    assert_eq!(expected_component.version, version);
+    let code_hash = vm_component.get(2).unwrap().decode_as::<asn1::OctetString>().unwrap();
+    assert_eq!(expected_component.code_hash, code_hash.as_bytes());
+    let authority_hash = vm_component.get(3).unwrap().decode_as::<asn1::OctetString>().unwrap();
+    assert_eq!(expected_component.authority_hash, authority_hash.as_bytes());
     Ok(())
 }
 
@@ -200,22 +210,22 @@
     certificate: &[u8],
     maced_public_key: &[u8],
     csr: &Csr,
-    parent_certificate: &X509Certificate,
+    parent_certificate: &Certificate,
 ) -> Result<()> {
     let cose_mac = CoseMac0::from_slice(maced_public_key)?;
     let authority_public_key =
         EcKey::from_cose_public_key_slice(&cose_mac.payload.unwrap()).unwrap();
-    let (remaining, cert) = X509Certificate::from_der(certificate)?;
-    assert!(remaining.is_empty());
+    let cert = Certificate::from_der(certificate).unwrap();
 
     // Checks the certificate signature against the authority public key.
-    const ECDSA_WITH_SHA_256: Oid<'static> = oid!(1.2.840 .10045 .4 .3 .2);
-    let expected_algorithm =
-        AlgorithmIdentifier { algorithm: ECDSA_WITH_SHA_256, parameters: None };
+    const ECDSA_WITH_SHA_256: ObjectIdentifier =
+        ObjectIdentifier::new_unwrap("1.2.840.10045.4.3.2");
+    let expected_algorithm = AlgorithmIdentifier { oid: ECDSA_WITH_SHA_256, parameters: None };
     assert_eq!(expected_algorithm, cert.signature_algorithm);
-    let digest = sha256(cert.tbs_certificate.as_ref()).unwrap();
+    let tbs_cert = cert.tbs_certificate;
+    let digest = sha256(&tbs_cert.to_der().unwrap()).unwrap();
     authority_public_key
-        .ecdsa_verify(cert.signature_value.as_ref(), &digest)
+        .ecdsa_verify(cert.signature.raw_bytes(), &digest)
         .expect("Failed to verify the certificate signature with the authority public key");
 
     // Checks that the certificate's subject public key is equal to the key in the CSR.
@@ -225,38 +235,39 @@
     let subject_public_key = EcKey::from_cose_public_key_slice(&csr_payload.public_key).unwrap();
     let expected_spki_data =
         PKey::try_from(subject_public_key).unwrap().subject_public_key_info().unwrap();
-    let (remaining, expected_spki) = SubjectPublicKeyInfo::from_der(&expected_spki_data)?;
-    assert!(remaining.is_empty());
-    assert_eq!(&expected_spki, cert.public_key());
+    let expected_spki = SubjectPublicKeyInfo::from_der(&expected_spki_data).unwrap();
+    assert_eq!(expected_spki, tbs_cert.subject_public_key_info);
 
     // Checks the certificate extension.
-    const ATTESTATION_EXTENSION_OID: Oid<'static> = oid!(1.3.6 .1 .4 .1 .11129 .2 .1 .29 .1);
-    let extensions = cert.extensions();
+    const ATTESTATION_EXTENSION_OID: ObjectIdentifier =
+        ObjectIdentifier::new_unwrap("1.3.6.1.4.1.11129.2.1.29.1");
+    let extensions = tbs_cert.extensions.unwrap();
     assert_eq!(1, extensions.len());
     let extension = &extensions[0];
-    assert_eq!(ATTESTATION_EXTENSION_OID, extension.oid);
+    assert_eq!(ATTESTATION_EXTENSION_OID, extension.extn_id);
     assert!(!extension.critical);
-    let (remaining, extension) = parse_der(extension.value)?;
-    assert!(remaining.is_empty());
-    let attestation_ext = extension.as_sequence()?;
+    let attestation_ext =
+        asn1::SequenceOf::<asn1::Any, 3>::from_der(extension.extn_value.as_bytes()).unwrap();
     assert_eq!(3, attestation_ext.len());
-    assert_eq!(csr_payload.challenge, attestation_ext[0].as_slice()?);
-    let is_vm_secure = attestation_ext[1].as_bool()?;
+    let challenge = attestation_ext.get(0).unwrap().decode_as::<asn1::OctetString>().unwrap();
+    assert_eq!(csr_payload.challenge, challenge.as_bytes());
+    let is_vm_secure = attestation_ext.get(1).unwrap().decode_as::<bool>().unwrap();
     assert!(
         !is_vm_secure,
         "The VM shouldn't be secure as the last payload added in the test is in Debug mode"
     );
-    let vm_components = attestation_ext[2].as_sequence()?;
-    check_vm_components(vm_components)?;
+    let vm_components =
+        attestation_ext.get(2).unwrap().decode_as::<asn1::SequenceOf<asn1::Any, 4>>().unwrap();
+    check_vm_components(&vm_components)?;
 
     // Checks other fields on the certificate
-    assert_eq!(X509Version::V3, cert.version());
-    assert_eq!(parent_certificate.validity(), cert.validity());
+    assert_eq!(Version::V3, tbs_cert.version);
+    assert_eq!(parent_certificate.tbs_certificate.validity, tbs_cert.validity);
     assert_eq!(
-        String::from("CN=Android Protected Virtual Machine Key"),
-        cert.subject().to_string()
+        Name::from_str("CN=Android Protected Virtual Machine Key").unwrap(),
+        tbs_cert.subject
     );
-    assert_eq!(parent_certificate.subject(), cert.issuer());
+    assert_eq!(parent_certificate.tbs_certificate.subject, tbs_cert.issuer);
 
     Ok(())
 }
diff --git a/service_vm/requests/src/client_vm.rs b/service_vm/requests/src/client_vm.rs
index 5b1bf6c..6ebed50 100644
--- a/service_vm/requests/src/client_vm.rs
+++ b/service_vm/requests/src/client_vm.rs
@@ -28,7 +28,7 @@
 use coset::{AsCborValue, CborSerializable, CoseSign, CoseSign1};
 use der::{Decode, Encode};
 use diced_open_dice::{DiceArtifacts, HASH_SIZE};
-use log::error;
+use log::{error, info};
 use microdroid_kernel_hashes::{INITRD_DEBUG_HASH, INITRD_NORMAL_HASH, KERNEL_HASH};
 use service_vm_comm::{ClientVmAttestationParams, Csr, CsrPayload, RequestProcessingError};
 use x509_cert::{certificate::Certificate, name::Name};
@@ -86,9 +86,11 @@
 
     // Builds the TBSCertificate.
     // The serial number can be up to 20 bytes according to RFC5280 s4.1.2.2.
-    // In this case, a serial number with a length of 20 bytes is used to ensure that each
+    // In this case, a serial number with a length of 16 bytes is used to ensure that each
     // certificate signed by RKP VM has a unique serial number.
-    let mut serial_number = [0u8; 20];
+    // Attention: Do not use 20 bytes here as when the MSB is 1, a leading 0 byte can be
+    // added during the encoding to make the serial number length exceed 20 bytes.
+    let mut serial_number = [0u8; 16];
     rand_bytes(&mut serial_number)?;
     let subject = Name::encode_from_string("CN=Android Protected Virtual Machine Key")?;
     let rkp_cert = Certificate::from_der(&params.remotely_provisioned_cert)?;
@@ -98,6 +100,8 @@
         } else {
             Vec::new()
         };
+
+    info!("The client VM DICE chain validation succeeded. Beginning to generate the certificate.");
     let attestation_ext = cert::AttestationExtension::new(
         &csr_payload.challenge,
         client_vm_dice_chain.all_entries_are_secure(),
diff --git a/virtualizationmanager/src/aidl.rs b/virtualizationmanager/src/aidl.rs
index 8c2099f..d775555 100644
--- a/virtualizationmanager/src/aidl.rs
+++ b/virtualizationmanager/src/aidl.rs
@@ -18,7 +18,7 @@
 use crate::atom::{
     write_vm_booted_stats, write_vm_creation_stats};
 use crate::composite::make_composite_image;
-use crate::crosvm::{CrosvmConfig, DiskFile, PayloadState, VfioDevice, VmContext, VmInstance, VmState};
+use crate::crosvm::{CrosvmConfig, DiskFile, PayloadState, VmContext, VmInstance, VmState};
 use crate::debug_config::DebugConfig;
 use crate::payload::{add_microdroid_payload_images, add_microdroid_system_images, add_microdroid_vendor_image};
 use crate::selinux::{getfilecon, SeContext};
@@ -510,14 +510,7 @@
                         .or_binder_exception(ExceptionCode::ILLEGAL_ARGUMENT);
                 }
             }
-            let devices = GLOBAL_SERVICE
-                .bindDevicesToVfioDriver(&config.devices)?
-                .into_iter()
-                .map(|x| VfioDevice {
-                    sysfs_path: PathBuf::from(&x.sysfsPath),
-                    dtbo_label: x.dtboLabel,
-                })
-                .collect::<Vec<_>>();
+            let devices = GLOBAL_SERVICE.bindDevicesToVfioDriver(&config.devices)?;
             let dtbo_file = File::from(
                 GLOBAL_SERVICE
                     .getDtboFile()?
diff --git a/virtualizationmanager/src/crosvm.rs b/virtualizationmanager/src/crosvm.rs
index f0c3e4b..4b3478e 100644
--- a/virtualizationmanager/src/crosvm.rs
+++ b/virtualizationmanager/src/crosvm.rs
@@ -47,6 +47,7 @@
     VirtualMachineAppConfig::DebugLevel::DebugLevel
 };
 use android_system_virtualizationservice_internal::aidl::android::system::virtualizationservice_internal::IGlobalVmContext::IGlobalVmContext;
+use android_system_virtualizationservice_internal::aidl::android::system::virtualizationservice_internal::IBoundDevice::IBoundDevice;
 use binder::Strong;
 use android_system_virtualmachineservice::aidl::android::system::virtualmachineservice::IVirtualMachineService::IVirtualMachineService;
 use tombstoned_client::{TombstonedConnection, DebuggerdDumpType};
@@ -127,11 +128,7 @@
     pub writable: bool,
 }
 
-#[derive(Clone, Debug)]
-pub struct VfioDevice {
-    pub sysfs_path: PathBuf,
-    pub dtbo_label: String,
-}
+type VfioDevice = Strong<dyn IBoundDevice>;
 
 /// The lifecycle state which the payload in the VM has reported itself to be in.
 ///
@@ -412,10 +409,7 @@
             error!("Error removing temporary files from {:?}: {}", self.temporary_directory, e);
         });
 
-        // TODO(b/278008182): clean up assigned devices.
-        for device in vfio_devices.iter() {
-            info!("NOT RELEASING {device:?}");
-        }
+        drop(vfio_devices); // Cleanup devices.
     }
 
     /// Waits until payload is started, or timeout expires. When timeout occurs, kill
@@ -706,7 +700,7 @@
 
 fn vfio_argument_for_platform_device(device: &VfioDevice) -> Result<String, Error> {
     // Check platform device exists
-    let path = device.sysfs_path.canonicalize()?;
+    let path = Path::new(&device.getSysfsPath()?).canonicalize()?;
     if !path.starts_with(SYSFS_PLATFORM_DEVICES_PATH) {
         bail!("{path:?} is not a platform device");
     }
@@ -718,7 +712,7 @@
     }
 
     if let Some(p) = path.to_str() {
-        Ok(format!("--vfio={p},iommu=pkvm-iommu,dt-symbol={0}", device.dtbo_label))
+        Ok(format!("--vfio={p},iommu=pkvm-iommu,dt-symbol={0}", device.getDtboLabel()?))
     } else {
         bail!("invalid path {path:?}");
     }
diff --git a/virtualizationservice/Android.bp b/virtualizationservice/Android.bp
index 3f8d193..e0bb97f 100644
--- a/virtualizationservice/Android.bp
+++ b/virtualizationservice/Android.bp
@@ -32,9 +32,11 @@
         "libavflog",
         "libbinder_rs",
         "libhypervisor_props",
+        "liblazy_static",
         "liblibc",
         "liblog_rust",
         "libnix",
+        "libopenssl",
         "librkpd_client",
         "librustutils",
         "libvmclient",
@@ -45,7 +47,6 @@
         "libserde_xml_rs",
         "libservice_vm_comm",
         "libservice_vm_manager",
-        "libx509_parser",
     ],
     apex_available: ["com.android.virt"],
 }
diff --git a/virtualizationservice/aidl/android/system/virtualizationservice_internal/IBoundDevice.aidl b/virtualizationservice/aidl/android/system/virtualizationservice_internal/IBoundDevice.aidl
new file mode 100644
index 0000000..4a37bf7
--- /dev/null
+++ b/virtualizationservice/aidl/android/system/virtualizationservice_internal/IBoundDevice.aidl
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2023 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.
+ */
+package android.system.virtualizationservice_internal;
+
+/** A device bound to VFIO driver. */
+interface IBoundDevice {
+    /** Path to SysFS node of the device. */
+    String getSysfsPath();
+
+    /** DTBO label of the device. */
+    String getDtboLabel();
+}
diff --git a/virtualizationservice/aidl/android/system/virtualizationservice_internal/IVfioHandler.aidl b/virtualizationservice/aidl/android/system/virtualizationservice_internal/IVfioHandler.aidl
index 01906cb..2cf4efd 100644
--- a/virtualizationservice/aidl/android/system/virtualizationservice_internal/IVfioHandler.aidl
+++ b/virtualizationservice/aidl/android/system/virtualizationservice_internal/IVfioHandler.aidl
@@ -20,16 +20,22 @@
 import android.system.virtualizationservice_internal.AtomVmBooted;
 import android.system.virtualizationservice_internal.AtomVmCreationRequested;
 import android.system.virtualizationservice_internal.AtomVmExited;
+import android.system.virtualizationservice_internal.IBoundDevice;
 import android.system.virtualizationservice_internal.IGlobalVmContext;
 
 /** VFIO related methods which should be done as root. */
 interface IVfioHandler {
+    parcelable VfioDev {
+        String sysfsPath;
+        String dtboLabel;
+    }
     /**
      * Bind given devices to vfio driver.
      *
-     * @param devices paths of sysfs nodes of devices to assign.
+     * @param devices a list of pairs (sysfs path, DTBO node label) for devices.
+     * @return IBoundDevice list representing a VFIO bound devices.
      */
-    void bindDevicesToVfioDriver(in String[] devices);
+    IBoundDevice[] bindDevicesToVfioDriver(in VfioDev[] devices);
 
     /**
      * Store VM DTBO via the file descriptor.
diff --git a/virtualizationservice/aidl/android/system/virtualizationservice_internal/IVirtualizationServiceInternal.aidl b/virtualizationservice/aidl/android/system/virtualizationservice_internal/IVirtualizationServiceInternal.aidl
index a2cb693..dd94526 100644
--- a/virtualizationservice/aidl/android/system/virtualizationservice_internal/IVirtualizationServiceInternal.aidl
+++ b/virtualizationservice/aidl/android/system/virtualizationservice_internal/IVirtualizationServiceInternal.aidl
@@ -21,13 +21,10 @@
 import android.system.virtualizationservice_internal.AtomVmBooted;
 import android.system.virtualizationservice_internal.AtomVmCreationRequested;
 import android.system.virtualizationservice_internal.AtomVmExited;
+import android.system.virtualizationservice_internal.IBoundDevice;
 import android.system.virtualizationservice_internal.IGlobalVmContext;
 
 interface IVirtualizationServiceInternal {
-    parcelable BoundDevice {
-        String sysfsPath;
-        String dtboLabel;
-    }
     /**
      * Removes the memlock rlimit of the calling process.
      *
@@ -78,9 +75,9 @@
      * Bind given devices to vfio driver.
      *
      * @param devices paths of sysfs nodes of devices to assign.
-     * @return a list of pairs (sysfs path, DTBO node label) for devices.
+     * @return a list of IBoundDevices representing VFIO bound devices.
      */
-    BoundDevice[] bindDevicesToVfioDriver(in String[] devices);
+    IBoundDevice[] bindDevicesToVfioDriver(in String[] devices);
 
     /** Returns a read-only file descriptor of the VM DTBO file. */
     ParcelFileDescriptor getDtboFile();
diff --git a/virtualizationservice/src/aidl.rs b/virtualizationservice/src/aidl.rs
index 3ac1e60..a1a1fb9 100644
--- a/virtualizationservice/src/aidl.rs
+++ b/virtualizationservice/src/aidl.rs
@@ -28,15 +28,17 @@
     AtomVmBooted::AtomVmBooted,
     AtomVmCreationRequested::AtomVmCreationRequested,
     AtomVmExited::AtomVmExited,
+    IBoundDevice::IBoundDevice,
     IGlobalVmContext::{BnGlobalVmContext, IGlobalVmContext},
-    IVirtualizationServiceInternal::BoundDevice::BoundDevice,
     IVirtualizationServiceInternal::IVirtualizationServiceInternal,
     IVfioHandler::{BpVfioHandler, IVfioHandler},
+    IVfioHandler::VfioDev::VfioDev,
 };
 use android_system_virtualmachineservice::aidl::android::system::virtualmachineservice::IVirtualMachineService::VM_TOMBSTONES_SERVICE_PORT;
 use anyhow::{anyhow, ensure, Context, Result};
 use avflog::LogResult;
 use binder::{self, wait_for_interface, BinderFeatures, ExceptionCode, Interface, LazyServiceGuard, Status, Strong, IntoBinderResult};
+use lazy_static::lazy_static;
 use libc::VMADDR_CID_HOST;
 use log::{error, info, warn};
 use rkpd_client::get_rkpd_attestation_key;
@@ -52,7 +54,7 @@
 use tombstoned_client::{DebuggerdDumpType, TombstonedConnection};
 use vsock::{VsockListener, VsockStream};
 use nix::unistd::{chown, Uid};
-use x509_parser::{traits::FromDer, certificate::X509Certificate};
+use openssl::x509::X509;
 
 /// The unique ID of a VM used (together with a port number) for vsock communication.
 pub type Cid = u32;
@@ -71,6 +73,12 @@
 
 const CHUNK_RECV_MAX_LEN: usize = 1024;
 
+lazy_static! {
+    static ref VFIO_SERVICE: Strong<dyn IVfioHandler> =
+        wait_for_interface(<BpVfioHandler as IVfioHandler>::get_descriptor())
+            .expect("Could not connect to VfioHandler");
+}
+
 fn is_valid_guest_cid(cid: Cid) -> bool {
     (GUEST_CID_MIN..=GUEST_CID_MAX).contains(&cid)
 }
@@ -219,24 +227,26 @@
             .collect::<Vec<_>>())
     }
 
-    fn bindDevicesToVfioDriver(&self, devices: &[String]) -> binder::Result<Vec<BoundDevice>> {
+    fn bindDevicesToVfioDriver(
+        &self,
+        devices: &[String],
+    ) -> binder::Result<Vec<Strong<dyn IBoundDevice>>> {
         check_use_custom_virtual_machine()?;
 
-        let vfio_service: Strong<dyn IVfioHandler> =
-            wait_for_interface(<BpVfioHandler as IVfioHandler>::get_descriptor())?;
-        vfio_service.bindDevicesToVfioDriver(devices)?;
-
-        Ok(get_assignable_devices()?
+        let devices = get_assignable_devices()?
             .device
             .into_iter()
             .filter_map(|x| {
                 if devices.contains(&x.sysfs_path) {
-                    Some(BoundDevice { sysfsPath: x.sysfs_path, dtboLabel: x.dtbo_label })
+                    Some(VfioDev { sysfsPath: x.sysfs_path, dtboLabel: x.dtbo_label })
                 } else {
+                    warn!("device {} is not assignable", x.sysfs_path);
                     None
                 }
             })
-            .collect::<Vec<_>>())
+            .collect::<Vec<VfioDev>>();
+
+        VFIO_SERVICE.bindDevicesToVfioDriver(devices.as_slice())
     }
 
     fn getDtboFile(&self) -> binder::Result<ParcelFileDescriptor> {
@@ -303,10 +313,10 @@
 fn split_x509_certificate_chain(mut cert_chain: &[u8]) -> Result<Vec<Certificate>> {
     let mut out = Vec::new();
     while !cert_chain.is_empty() {
-        let (remaining, _) = X509Certificate::from_der(cert_chain)?;
-        let end = cert_chain.len() - remaining.len();
+        let cert = X509::from_der(cert_chain)?;
+        let end = cert.to_der()?.len();
         out.push(Certificate { encodedCertificate: cert_chain[..end].to_vec() });
-        cert_chain = remaining;
+        cert_chain = &cert_chain[end..];
     }
     Ok(out)
 }
@@ -424,10 +434,7 @@
 
             // Open a write-only file descriptor for vfio_handler.
             let write_fd = File::create(&path).context("Failed to create VM DTBO file")?;
-
-            let vfio_service: Strong<dyn IVfioHandler> =
-                wait_for_interface(<BpVfioHandler as IVfioHandler>::get_descriptor())?;
-            vfio_service.writeVmDtbo(&ParcelFileDescriptor::new(write_fd))?;
+            VFIO_SERVICE.writeVmDtbo(&ParcelFileDescriptor::new(write_fd))?;
 
             // Open read-only. This FD will be cached and returned to clients.
             let read_fd = File::open(&path).context("Failed to open VM DTBO file")?;
@@ -599,8 +606,8 @@
 
         assert_eq!(4, cert_chain.len());
         for cert in cert_chain {
-            let (remaining, _) = X509Certificate::from_der(&cert.encodedCertificate)?;
-            assert!(remaining.is_empty());
+            let x509_cert = X509::from_der(&cert.encodedCertificate)?;
+            assert_eq!(x509_cert.to_der()?.len(), cert.encodedCertificate.len());
         }
         Ok(())
     }
diff --git a/virtualizationservice/vfio_handler/src/aidl.rs b/virtualizationservice/vfio_handler/src/aidl.rs
index 63f19c6..c0967af 100644
--- a/virtualizationservice/vfio_handler/src/aidl.rs
+++ b/virtualizationservice/vfio_handler/src/aidl.rs
@@ -15,10 +15,13 @@
 //! Implementation of the AIDL interface of the VirtualizationService.
 
 use anyhow::{anyhow, Context};
+use android_system_virtualizationservice_internal::aidl::android::system::virtualizationservice_internal::IBoundDevice::{IBoundDevice, BnBoundDevice};
 use android_system_virtualizationservice_internal::aidl::android::system::virtualizationservice_internal::IVfioHandler::IVfioHandler;
+use android_system_virtualizationservice_internal::aidl::android::system::virtualizationservice_internal::IVfioHandler::VfioDev::VfioDev;
 use android_system_virtualizationservice_internal::binder::ParcelFileDescriptor;
-use binder::{self, ExceptionCode, Interface, IntoBinderResult};
+use binder::{self, BinderFeatures, ExceptionCode, Interface, IntoBinderResult, Strong};
 use lazy_static::lazy_static;
+use log::error;
 use std::fs::{read_link, write, File};
 use std::io::{Read, Seek, SeekFrom, Write};
 use std::mem::size_of;
@@ -30,6 +33,38 @@
     FromBytes,
 };
 
+// Device bound to VFIO driver.
+struct BoundDevice {
+    sysfs_path: String,
+    dtbo_label: String,
+}
+
+impl Interface for BoundDevice {}
+
+impl IBoundDevice for BoundDevice {
+    fn getSysfsPath(&self) -> binder::Result<String> {
+        Ok(self.sysfs_path.clone())
+    }
+
+    fn getDtboLabel(&self) -> binder::Result<String> {
+        Ok(self.dtbo_label.clone())
+    }
+}
+
+impl Drop for BoundDevice {
+    fn drop(&mut self) {
+        unbind_device(Path::new(&self.sysfs_path)).unwrap_or_else(|e| {
+            error!("did not restore {} driver: {}", self.sysfs_path, e);
+        });
+    }
+}
+
+impl BoundDevice {
+    fn new_binder(sysfs_path: String, dtbo_label: String) -> Strong<dyn IBoundDevice> {
+        BnBoundDevice::new_binder(BoundDevice { sysfs_path, dtbo_label }, BinderFeatures::default())
+    }
+}
+
 #[derive(Debug, Default)]
 pub struct VfioHandler {}
 
@@ -42,14 +77,22 @@
 impl Interface for VfioHandler {}
 
 impl IVfioHandler for VfioHandler {
-    fn bindDevicesToVfioDriver(&self, devices: &[String]) -> binder::Result<()> {
+    fn bindDevicesToVfioDriver(
+        &self,
+        devices: &[VfioDev],
+    ) -> binder::Result<Vec<Strong<dyn IBoundDevice>>> {
         // permission check is already done by IVirtualizationServiceInternal.
         if !*IS_VFIO_SUPPORTED {
             return Err(anyhow!("VFIO-platform not supported"))
                 .or_binder_exception(ExceptionCode::UNSUPPORTED_OPERATION);
         }
-        devices.iter().try_for_each(|x| bind_device(Path::new(x)))?;
-        Ok(())
+        devices
+            .iter()
+            .map(|d| {
+                bind_device(Path::new(&d.sysfsPath))?;
+                Ok(BoundDevice::new_binder(d.sysfsPath.clone(), d.dtboLabel.clone()))
+            })
+            .collect::<binder::Result<Vec<_>>>()
     }
 
     fn writeVmDtbo(&self, dtbo_fd: &ParcelFileDescriptor) -> binder::Result<()> {
@@ -79,6 +122,11 @@
 const VFIO_PLATFORM_DRIVER_PATH: &str = "/sys/bus/platform/drivers/vfio-platform";
 const SYSFS_PLATFORM_DRIVERS_PROBE_PATH: &str = "/sys/bus/platform/drivers_probe";
 const DT_TABLE_MAGIC: u32 = 0xd7b7ab1e;
+const VFIO_PLATFORM_DRIVER_NAME: &str = "vfio-platform";
+// To remove the override and match the device driver by "compatible" string again,
+// driver_override file must be cleared. Writing an empty string (same as
+// `echo -n "" > driver_override`) won't' clear the file, so append a newline char.
+const DEFAULT_DRIVER: &str = "\n";
 
 /// The structure of DT table header in dtbo.img.
 /// https://source.android.com/docs/core/architecture/dto/partitions
@@ -146,18 +194,15 @@
     group.to_str()?.parse().ok()
 }
 
-fn is_bound_to_vfio_driver(path: &Path) -> bool {
-    let Ok(driver_path) = read_link(path.join("driver")) else {
-        return false;
-    };
-    let Some(driver) = driver_path.file_name() else {
-        return false;
-    };
-    driver.to_str().unwrap_or("") == "vfio-platform"
+fn current_driver(path: &Path) -> Option<String> {
+    let driver_path = read_link(path.join("driver")).ok()?;
+    let bound_driver = driver_path.file_name()?;
+    bound_driver.to_str().map(str::to_string)
 }
 
-fn bind_vfio_driver(path: &Path) -> binder::Result<()> {
-    if is_bound_to_vfio_driver(path) {
+// Try to bind device driver by writing its name to driver_override and triggering driver probe.
+fn try_bind_driver(path: &Path, driver: &str) -> binder::Result<()> {
+    if Some(driver) == current_driver(path).as_deref() {
         // already bound
         return Ok(());
     }
@@ -177,10 +222,13 @@
             .with_context(|| format!("could not unbind {device_str}"))
             .or_service_specific_exception(-1)?;
     }
+    if path.join("driver").exists() {
+        return Err(anyhow!("could not unbind {device_str}")).or_service_specific_exception(-1);
+    }
 
-    // bind to VFIO
-    write(path.join("driver_override"), b"vfio-platform")
-        .with_context(|| format!("could not bind {device_str} to vfio-platform"))
+    // bind to new driver
+    write(path.join("driver_override"), driver.as_bytes())
+        .with_context(|| format!("could not bind {device_str} to '{driver}' driver"))
         .or_service_specific_exception(-1)?;
 
     write(SYSFS_PLATFORM_DRIVERS_PROBE_PATH, device_str.as_bytes())
@@ -188,13 +236,9 @@
         .or_service_specific_exception(-1)?;
 
     // final check
-    if !is_bound_to_vfio_driver(path) {
-        return Err(anyhow!("{path:?} still not bound to vfio driver"))
-            .or_service_specific_exception(-1);
-    }
-
-    if get_device_iommu_group(path).is_none() {
-        return Err(anyhow!("can't get iommu group for {path:?}"))
+    let new_driver = current_driver(path);
+    if new_driver.is_none() || Some(driver) != new_driver.as_deref() && driver != DEFAULT_DRIVER {
+        return Err(anyhow!("{path:?} still not bound to '{driver}' driver"))
             .or_service_specific_exception(-1);
     }
 
@@ -208,7 +252,29 @@
         .or_binder_exception(ExceptionCode::ILLEGAL_ARGUMENT)?;
 
     check_platform_device(&path)?;
-    bind_vfio_driver(&path)
+    try_bind_driver(&path, VFIO_PLATFORM_DRIVER_NAME)?;
+
+    if get_device_iommu_group(&path).is_none() {
+        Err(anyhow!("can't get iommu group for {path:?}")).or_service_specific_exception(-1)
+    } else {
+        Ok(())
+    }
+}
+
+fn unbind_device(path: &Path) -> binder::Result<()> {
+    let path = path
+        .canonicalize()
+        .with_context(|| format!("can't canonicalize {path:?}"))
+        .or_binder_exception(ExceptionCode::ILLEGAL_ARGUMENT)?;
+
+    check_platform_device(&path)?;
+    try_bind_driver(&path, DEFAULT_DRIVER)?;
+
+    if Some(VFIO_PLATFORM_DRIVER_NAME) == current_driver(&path).as_deref() {
+        Err(anyhow!("{path:?} still bound to vfio driver")).or_service_specific_exception(-1)
+    } else {
+        Ok(())
+    }
 }
 
 fn get_dtbo_img_path() -> binder::Result<PathBuf> {