Merge "[x509] Parse certificate chain from RKPD into individual certificate" into main
diff --git a/TEST_MAPPING b/TEST_MAPPING
index 6983fde..4da96c8 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -117,6 +117,9 @@
       "path": "packages/modules/Virtualization/service_vm/requests"
     },
     {
+      "path": "packages/modules/Virtualization/virtualizationservice"
+    },
+    {
       "path": "packages/modules/Virtualization/vm"
     },
     {
diff --git a/microdroid_manager/aidl/android/system/virtualization/payload/IVmPayloadService.aidl b/microdroid_manager/aidl/android/system/virtualization/payload/IVmPayloadService.aidl
index 51796f1..4813b35 100644
--- a/microdroid_manager/aidl/android/system/virtualization/payload/IVmPayloadService.aidl
+++ b/microdroid_manager/aidl/android/system/virtualization/payload/IVmPayloadService.aidl
@@ -59,8 +59,8 @@
          * Sequence of DER-encoded X.509 certificates that make up the attestation
          * key's certificate chain.
          *
-         * The certificate chain starts with a root certificate and ends with a leaf
-         * certificate covering the attested public key.
+         * The certificate chain starts with a leaf certificate covering the attested
+         * public key and ends with a root certificate.
          */
         Certificate[] certificateChain;
     }
diff --git a/virtualizationservice/Android.bp b/virtualizationservice/Android.bp
index 5cf2a39..3f8d193 100644
--- a/virtualizationservice/Android.bp
+++ b/virtualizationservice/Android.bp
@@ -2,8 +2,8 @@
     default_applicable_licenses: ["Android-Apache-2.0"],
 }
 
-rust_binary {
-    name: "virtualizationservice",
+rust_defaults {
+    name: "virtualizationservice_defaults",
     crate_name: "virtualizationservice",
     defaults: ["avf_build_flags_rust"],
     edition: "2021",
@@ -45,13 +45,39 @@
         "libserde_xml_rs",
         "libservice_vm_comm",
         "libservice_vm_manager",
+        "libx509_parser",
     ],
     apex_available: ["com.android.virt"],
 }
 
+rust_binary {
+    name: "virtualizationservice",
+    defaults: ["virtualizationservice_defaults"],
+}
+
 xsd_config {
     name: "assignable_devices",
     srcs: ["assignable_devices.xsd"],
     api_dir: "schema",
     package_name: "android.system.virtualizationservice",
 }
+
+rust_test {
+    name: "virtualizationservice_test",
+    defaults: ["virtualizationservice_defaults"],
+    test_suites: ["general-tests"],
+    data: [
+        ":test_rkp_cert_chain",
+    ],
+}
+
+// The chain originates from a CTS test for Keymint, with the Keymint certificate
+// (leaf certificate) truncated.
+//
+// The certificate chain begins with a leaf certificate obtained from RKP and ends
+// with a root certificate. Each certificate in the chain possesses a signature that
+// is signed by the private key of the subsequent certificate in the chain.
+filegroup {
+    name: "test_rkp_cert_chain",
+    srcs: ["testdata/rkp_cert_chain.der"],
+}
diff --git a/virtualizationservice/TEST_MAPPING b/virtualizationservice/TEST_MAPPING
new file mode 100644
index 0000000..4fef83c
--- /dev/null
+++ b/virtualizationservice/TEST_MAPPING
@@ -0,0 +1,9 @@
+// When adding or removing tests here, don't forget to amend _all_modules list in
+// wireless/android/busytown/ath_config/configs/prod/avf/tests.gcl
+{
+  "avf-presubmit" : [
+    {
+      "name" : "virtualizationservice_test"
+    }
+  ]
+}
diff --git a/virtualizationservice/src/aidl.rs b/virtualizationservice/src/aidl.rs
index 7cdfdc6..d1f7291 100644
--- a/virtualizationservice/src/aidl.rs
+++ b/virtualizationservice/src/aidl.rs
@@ -52,6 +52,7 @@
 use tombstoned_client::{DebuggerdDumpType, TombstonedConnection};
 use vsock::{VsockListener, VsockStream};
 use nix::unistd::{chown, Uid};
+use x509_parser::{traits::FromDer, certificate::X509Certificate};
 
 /// The unique ID of a VM used (together with a port number) for vsock communication.
 pub type Cid = u32;
@@ -166,35 +167,42 @@
         requester_uid: i32,
     ) -> binder::Result<Vec<Certificate>> {
         check_manage_access()?;
-        info!("Received csr. Requestting attestation...");
-        if cfg!(remote_attestation) {
-            let attestation_key = get_rkpd_attestation_key(
-                REMOTELY_PROVISIONED_COMPONENT_SERVICE_NAME,
-                requester_uid as u32,
-            )
-            .context("Failed to retrieve the remotely provisioned keys")
-            .with_log()
-            .or_service_specific_exception(-1)?;
-            let certificate = request_attestation(csr, &attestation_key.keyBlob)
-                .context("Failed to request attestation")
-                .with_log()
-                .or_service_specific_exception(-1)?;
-            // TODO(b/309780089): Parse the remotely provisioned certificate chain into
-            // individual certificates.
-            let mut certificate_chain =
-                vec![Certificate { encodedCertificate: attestation_key.encodedCertChain }];
-            certificate_chain.push(Certificate { encodedCertificate: certificate });
-            Ok(certificate_chain)
-        } else {
-            Err(Status::new_exception_str(
+        if !cfg!(remote_attestation) {
+            return Err(Status::new_exception_str(
                 ExceptionCode::UNSUPPORTED_OPERATION,
                 Some(
                     "requestAttestation is not supported with the remote_attestation feature \
                      disabled",
                 ),
             ))
-            .with_log()
+            .with_log();
         }
+        info!("Received csr. Requestting attestation...");
+        let attestation_key = get_rkpd_attestation_key(
+            REMOTELY_PROVISIONED_COMPONENT_SERVICE_NAME,
+            requester_uid as u32,
+        )
+        .context("Failed to retrieve the remotely provisioned keys")
+        .with_log()
+        .or_service_specific_exception(-1)?;
+        let mut certificate_chain = split_x509_certificate_chain(&attestation_key.encodedCertChain)
+            .context("Failed to split the remotely provisioned certificate chain")
+            .with_log()
+            .or_service_specific_exception(-1)?;
+        if certificate_chain.is_empty() {
+            return Err(Status::new_service_specific_error_str(
+                -1,
+                Some("The certificate chain should contain at least 1 certificate"),
+            ))
+            .with_log();
+        }
+        let certificate = request_attestation(csr, &attestation_key.keyBlob)
+            .context("Failed to request attestation")
+            .with_log()
+            .or_service_specific_exception(-1)?;
+        certificate_chain.insert(0, Certificate { encodedCertificate: certificate });
+
+        Ok(certificate_chain)
     }
 
     fn getAssignableDevices(&self) -> binder::Result<Vec<AssignableDevice>> {
@@ -288,6 +296,17 @@
     Ok(devices)
 }
 
+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();
+        out.push(Certificate { encodedCertificate: cert_chain[..end].to_vec() });
+        cert_chain = remaining;
+    }
+    Ok(out)
+}
+
 #[derive(Debug, Default)]
 struct GlobalVmInstance {
     /// The unique CID assigned to the VM for vsock communication.
@@ -561,3 +580,24 @@
 fn check_use_custom_virtual_machine() -> binder::Result<()> {
     check_permission("android.permission.USE_CUSTOM_VIRTUAL_MACHINE")
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fs;
+
+    const TEST_RKP_CERT_CHAIN_PATH: &str = "testdata/rkp_cert_chain.der";
+
+    #[test]
+    fn splitting_x509_certificate_chain_succeeds() -> Result<()> {
+        let bytes = fs::read(TEST_RKP_CERT_CHAIN_PATH)?;
+        let cert_chain = split_x509_certificate_chain(&bytes)?;
+
+        assert_eq!(4, cert_chain.len());
+        for cert in cert_chain {
+            let (remaining, _) = X509Certificate::from_der(&cert.encodedCertificate)?;
+            assert!(remaining.is_empty());
+        }
+        Ok(())
+    }
+}
diff --git a/virtualizationservice/testdata/rkp_cert_chain.der b/virtualizationservice/testdata/rkp_cert_chain.der
new file mode 100644
index 0000000..f32065d
--- /dev/null
+++ b/virtualizationservice/testdata/rkp_cert_chain.der
Binary files differ
diff --git a/vm_payload/include/vm_payload.h b/vm_payload/include/vm_payload.h
index 78cd80d..3483e1d 100644
--- a/vm_payload/include/vm_payload.h
+++ b/vm_payload/include/vm_payload.h
@@ -224,8 +224,8 @@
  * Gets the number of certificates in the certificate chain.
  *
  * The certificate chain consists of a sequence of DER-encoded X.509 certificates that form
- * the attestation key's certificate chain. It starts with a root certificate and ends with a
- * leaf certificate covering the attested public key.
+ * the attestation key's certificate chain. It starts with a leaf certificate covering the attested
+ * public key and ends with a root certificate.
  *
  * \param result A pointer to the attestation result obtained from `AVmPayload_requestAttestation`
  *               when the attestation succeeds.
@@ -240,8 +240,8 @@
  * attestation result.
  *
  * The certificate chain consists of a sequence of DER-encoded X.509 certificates that form
- * the attestation key's certificate chain. It starts with a root certificate and ends with a
- * leaf certificate covering the attested public key.
+ * the attestation key's certificate chain. It starts with a leaf certificate covering the attested
+ * public key and ends with a root certificate.
  *
  * \param result A pointer to the attestation result obtained from `AVmPayload_requestAttestation`
  *               when the attestation succeeds.