[attestation] Rename the client VM attestation API

As agreed in the doc go/pvm-remote-attestation.

Bug: 303807447
Test: m com.android.virt
Test: run ServiceVmClientApp
Change-Id: Ic954aa60d69e42773c04230af9319e660352d6a9
diff --git a/microdroid_manager/aidl/android/system/virtualization/payload/IVmPayloadService.aidl b/microdroid_manager/aidl/android/system/virtualization/payload/IVmPayloadService.aidl
index 50d437f..b9a7a64 100644
--- a/microdroid_manager/aidl/android/system/virtualization/payload/IVmPayloadService.aidl
+++ b/microdroid_manager/aidl/android/system/virtualization/payload/IVmPayloadService.aidl
@@ -69,11 +69,13 @@
     byte[] getDiceAttestationCdi();
 
     /**
-     * Requests a certificate using the provided certificate signing request (CSR).
+     * Requests the remote attestation of the client VM.
      *
-     * TODO(b/271275206): Define the format of the CSR properly.
-     * @param csr the certificate signing request.
+     * The challenge will be included in the certificate chain in the attestation result,
+     * serving as proof of the freshness of the result.
+     *
+     * @param challenge the maximum supported challenge size is 64 bytes.
      * @return the X.509 encoded certificate.
      */
-    byte[] requestCertificate(in byte[] csr);
+    byte[] requestAttestation(in byte[] challenge);
 }
diff --git a/microdroid_manager/src/vm_payload_service.rs b/microdroid_manager/src/vm_payload_service.rs
index c611b11..5b5fb9e 100644
--- a/microdroid_manager/src/vm_payload_service.rs
+++ b/microdroid_manager/src/vm_payload_service.rs
@@ -66,9 +66,9 @@
         Ok(self.secret.dice().cdi_attest().to_vec())
     }
 
-    fn requestCertificate(&self, csr: &[u8]) -> binder::Result<Vec<u8>> {
+    fn requestAttestation(&self, challenge: &[u8]) -> binder::Result<Vec<u8>> {
         self.check_restricted_apis_allowed()?;
-        self.virtual_machine_service.requestCertificate(csr)
+        self.virtual_machine_service.requestAttestation(challenge)
     }
 }
 
diff --git a/service_vm/client_apk/src/main.rs b/service_vm/client_apk/src/main.rs
index 08d4168..bd48dc3 100644
--- a/service_vm/client_apk/src/main.rs
+++ b/service_vm/client_apk/src/main.rs
@@ -17,7 +17,7 @@
 use anyhow::Result;
 use log::{error, info};
 use std::{ffi::c_void, panic};
-use vm_payload_bindgen::AVmPayload_requestCertificate;
+use vm_payload_bindgen::AVmPayload_requestAttestation;
 
 /// Entry point of the Service VM client.
 #[allow(non_snake_case)]
@@ -40,25 +40,35 @@
 
 fn try_main() -> Result<()> {
     info!("Welcome to Service VM Client!");
-    let csr = b"Hello from Service VM";
-    info!("Sending: {:?}", csr);
-    let certificate = request_certificate(csr);
+    // The data below is only a placeholder generated randomly with urandom
+    let challenge = &[
+        0x6c, 0xad, 0x52, 0x50, 0x15, 0xe7, 0xf4, 0x1d, 0xa5, 0x60, 0x7e, 0xd2, 0x7d, 0xf1, 0x51,
+        0x67, 0xc3, 0x3e, 0x73, 0x9b, 0x30, 0xbd, 0x04, 0x20, 0x2e, 0xde, 0x3b, 0x1d, 0xc8, 0x07,
+        0x11, 0x7b,
+    ];
+    info!("Sending challenge: {:?}", challenge);
+    let certificate = request_attestation(challenge);
     info!("Certificate: {:?}", certificate);
     Ok(())
 }
 
-fn request_certificate(csr: &[u8]) -> Vec<u8> {
+fn request_attestation(challenge: &[u8]) -> Vec<u8> {
     // SAFETY: It is safe as we only request the size of the certificate in this call.
     let certificate_size = unsafe {
-        AVmPayload_requestCertificate(csr.as_ptr() as *const c_void, csr.len(), [].as_mut_ptr(), 0)
+        AVmPayload_requestAttestation(
+            challenge.as_ptr() as *const c_void,
+            challenge.len(),
+            [].as_mut_ptr(),
+            0,
+        )
     };
     let mut certificate = vec![0u8; certificate_size];
     // SAFETY: It is safe as we only write the data into the given buffer within the buffer
     // size in this call.
     unsafe {
-        AVmPayload_requestCertificate(
-            csr.as_ptr() as *const c_void,
-            csr.len(),
+        AVmPayload_requestAttestation(
+            challenge.as_ptr() as *const c_void,
+            challenge.len(),
             certificate.as_mut_ptr() as *mut c_void,
             certificate.len(),
         );
diff --git a/virtualizationmanager/src/aidl.rs b/virtualizationmanager/src/aidl.rs
index 5283ffe..da7dffe 100644
--- a/virtualizationmanager/src/aidl.rs
+++ b/virtualizationmanager/src/aidl.rs
@@ -1245,8 +1245,8 @@
         }
     }
 
-    fn requestCertificate(&self, csr: &[u8]) -> binder::Result<Vec<u8>> {
-        GLOBAL_SERVICE.requestCertificate(csr)
+    fn requestAttestation(&self, csr: &[u8]) -> binder::Result<Vec<u8>> {
+        GLOBAL_SERVICE.requestAttestation(csr)
     }
 }
 
diff --git a/virtualizationservice/aidl/android/system/virtualizationservice_internal/IVirtualizationServiceInternal.aidl b/virtualizationservice/aidl/android/system/virtualizationservice_internal/IVirtualizationServiceInternal.aidl
index 172dc59..099a2c0 100644
--- a/virtualizationservice/aidl/android/system/virtualizationservice_internal/IVirtualizationServiceInternal.aidl
+++ b/virtualizationservice/aidl/android/system/virtualizationservice_internal/IVirtualizationServiceInternal.aidl
@@ -56,12 +56,13 @@
     VirtualMachineDebugInfo[] debugListVms();
 
     /**
-     * Requests a certificate using the provided certificate signing request (CSR).
+     * Requests a certificate chain for the provided certificate signing request (CSR).
      *
-     * @param csr the certificate signing request.
-     * @return the X.509 encoded certificate.
+     * @param csr The certificate signing request.
+     * @return A sequence of DER-encoded X.509 certificates that make up the attestation
+     *         key's certificate chain. The attestation key is provided in the CSR.
      */
-    byte[] requestCertificate(in byte[] csr);
+    byte[] requestAttestation(in byte[] csr);
 
     /**
      * Get a list of assignable devices.
diff --git a/virtualizationservice/aidl/android/system/virtualmachineservice/IVirtualMachineService.aidl b/virtualizationservice/aidl/android/system/virtualmachineservice/IVirtualMachineService.aidl
index 7b90714..87d3056 100644
--- a/virtualizationservice/aidl/android/system/virtualmachineservice/IVirtualMachineService.aidl
+++ b/virtualizationservice/aidl/android/system/virtualmachineservice/IVirtualMachineService.aidl
@@ -46,10 +46,11 @@
     void notifyError(ErrorCode errorCode, in String message);
 
     /**
-     * Requests a certificate using the provided certificate signing request (CSR).
+     * Requests a certificate chain for the provided certificate signing request (CSR).
      *
-     * @param csr the certificate signing request.
-     * @return the X.509 encoded certificate.
+     * @param csr The certificate signing request.
+     * @return A sequence of DER-encoded X.509 certificates that make up the attestation
+     *         key's certificate chain. The attestation key is provided in the CSR.
      */
-    byte[] requestCertificate(in byte[] csr);
+    byte[] requestAttestation(in byte[] csr);
 }
diff --git a/virtualizationservice/src/aidl.rs b/virtualizationservice/src/aidl.rs
index a19ecd2..4daa0cf 100644
--- a/virtualizationservice/src/aidl.rs
+++ b/virtualizationservice/src/aidl.rs
@@ -16,7 +16,7 @@
 
 use crate::{get_calling_pid, get_calling_uid};
 use crate::atom::{forward_vm_booted_atom, forward_vm_creation_atom, forward_vm_exited_atom};
-use crate::rkpvm::request_certificate;
+use crate::rkpvm::request_attestation;
 use android_os_permissions_aidl::aidl::android::os::IPermissionController;
 use android_system_virtualizationservice::{
     aidl::android::system::virtualizationservice::AssignableDevice::AssignableDevice,
@@ -158,19 +158,20 @@
         Ok(cids)
     }
 
-    fn requestCertificate(&self, csr: &[u8]) -> binder::Result<Vec<u8>> {
+    fn requestAttestation(&self, csr: &[u8]) -> binder::Result<Vec<u8>> {
         check_manage_access()?;
-        info!("Received csr. Getting certificate...");
+        info!("Received csr. Requestting attestation...");
         if cfg!(remote_attestation) {
-            request_certificate(csr)
-                .context("Failed to get certificate")
+            request_attestation(csr)
+                .context("Failed to request attestation")
                 .with_log()
                 .or_service_specific_exception(-1)
         } else {
             Err(Status::new_exception_str(
                 ExceptionCode::UNSUPPORTED_OPERATION,
                 Some(
-                    "requestCertificate is not supported with the remote_attestation feature disabled",
+                    "requestAttestation is not supported with the remote_attestation feature \
+                     disabled",
                 ),
             ))
             .with_log()
diff --git a/virtualizationservice/src/rkpvm.rs b/virtualizationservice/src/rkpvm.rs
index d6e87eb..443b280 100644
--- a/virtualizationservice/src/rkpvm.rs
+++ b/virtualizationservice/src/rkpvm.rs
@@ -21,7 +21,7 @@
 use service_vm_comm::{GenerateCertificateRequestParams, Request, Response};
 use service_vm_manager::ServiceVm;
 
-pub(crate) fn request_certificate(csr: &[u8]) -> Result<Vec<u8>> {
+pub(crate) fn request_attestation(csr: &[u8]) -> Result<Vec<u8>> {
     let mut vm = ServiceVm::start()?;
 
     // TODO(b/271275206): Send the correct request type with client VM's
diff --git a/vm_payload/include-restricted/vm_payload_restricted.h b/vm_payload/include-restricted/vm_payload_restricted.h
index 1e0c3cc..ee92366 100644
--- a/vm_payload/include-restricted/vm_payload_restricted.h
+++ b/vm_payload/include-restricted/vm_payload_restricted.h
@@ -56,16 +56,21 @@
 size_t AVmPayload_getDiceAttestationCdi(void* _Nullable data, size_t size);
 
 /**
- * Requests a certificate using the provided certificate signing request (CSR).
+ * Requests the remote attestation of the client VM.
  *
- * \param csr A pointer to the CSR buffer.
- * \param csr_size The size of the CSR buffer.
+ * The challenge will be included in the certificate chain in the attestation result,
+ * serving as proof of the freshness of the result.
+ *
+ * \param challenge A pointer to the challenge buffer.
+ * \param challenge_size size of the challenge, the maximum supported challenge size is
+ *                       64 bytes. An error will be returned if an invalid challenge is
+ *                       passed.
  * \param buffer A pointer to the certificate buffer.
  * \param size number of bytes that can be written to the certificate buffer.
  *
  * \return the total size of the certificate
  */
-size_t AVmPayload_requestCertificate(const void* _Nonnull csr, size_t csr_size,
+size_t AVmPayload_requestAttestation(const void* _Nonnull challenge, size_t challenge_size,
                                      void* _Nullable buffer, size_t size)
         __INTRODUCED_IN(__ANDROID_API_V__);
 
diff --git a/vm_payload/libvm_payload.map.txt b/vm_payload/libvm_payload.map.txt
index f0d867e..32dd33b 100644
--- a/vm_payload/libvm_payload.map.txt
+++ b/vm_payload/libvm_payload.map.txt
@@ -1,13 +1,13 @@
 LIBVM_PAYLOAD {
   global:
-    AVmPayload_notifyPayloadReady;       # systemapi
-    AVmPayload_runVsockRpcServer;        # systemapi
-    AVmPayload_getVmInstanceSecret;      # systemapi
-    AVmPayload_getDiceAttestationChain;  # systemapi
-    AVmPayload_getDiceAttestationCdi;    # systemapi
-    AVmPayload_getApkContentsPath;       # systemapi
-    AVmPayload_getEncryptedStoragePath;  # systemapi
-    AVmPayload_requestCertificate;       # systemapi introduced=35
+    AVmPayload_notifyPayloadReady;       # systemapi introduced=UpsideDownCake
+    AVmPayload_runVsockRpcServer;        # systemapi introduced=UpsideDownCake
+    AVmPayload_getVmInstanceSecret;      # systemapi introduced=UpsideDownCake
+    AVmPayload_getDiceAttestationChain;  # systemapi introduced=UpsideDownCake
+    AVmPayload_getDiceAttestationCdi;    # systemapi introduced=UpsideDownCake
+    AVmPayload_getApkContentsPath;       # systemapi introduced=UpsideDownCake
+    AVmPayload_getEncryptedStoragePath;  # systemapi introduced=UpsideDownCake
+    AVmPayload_requestAttestation;       # systemapi introduced=VanillaIceCream
   local:
     *;
 };
diff --git a/vm_payload/src/api.rs b/vm_payload/src/api.rs
index 00d7299..93dbd1c 100644
--- a/vm_payload/src/api.rs
+++ b/vm_payload/src/api.rs
@@ -253,29 +253,31 @@
     get_vm_payload_service()?.getDiceAttestationCdi().context("Cannot get attestation CDI")
 }
 
-/// Requests a certificate using the provided certificate signing request (CSR).
-/// Panics on failure.
+/// Requests the remote attestation of the client VM.
+///
+/// The challenge will be included in the certificate chain in the attestation result,
+/// serving as proof of the freshness of the result.
 ///
 /// # Safety
 ///
 /// Behavior is undefined if any of the following conditions are violated:
 ///
-/// * `csr` must be [valid] for reads of `csr_size` bytes.
+/// * `challenge` must be [valid] for reads of `challenge_size` bytes.
 /// * `buffer` must be [valid] for writes of `size` bytes. `buffer` can be null if `size` is 0.
 ///
 /// [valid]: ptr#safety
 #[no_mangle]
-pub unsafe extern "C" fn AVmPayload_requestCertificate(
-    csr: *const u8,
-    csr_size: usize,
+pub unsafe extern "C" fn AVmPayload_requestAttestation(
+    challenge: *const u8,
+    challenge_size: usize,
     buffer: *mut u8,
     size: usize,
 ) -> usize {
     initialize_logging();
 
-    // SAFETY: See the requirements on `csr` above.
-    let csr = unsafe { std::slice::from_raw_parts(csr, csr_size) };
-    let certificate = unwrap_or_abort(try_request_certificate(csr));
+    // SAFETY: See the requirements on `challenge` above.
+    let challenge = unsafe { std::slice::from_raw_parts(challenge, challenge_size) };
+    let certificate = unwrap_or_abort(try_request_attestation(challenge));
 
     if size != 0 || buffer.is_null() {
         // SAFETY: See the requirements on `buffer` above. The number of bytes copied doesn't exceed
@@ -292,10 +294,10 @@
     certificate.len()
 }
 
-fn try_request_certificate(csr: &[u8]) -> Result<Vec<u8>> {
+fn try_request_attestation(challenge: &[u8]) -> Result<Vec<u8>> {
     let certificate = get_vm_payload_service()?
-        .requestCertificate(csr)
-        .context("Failed to request certificate")?;
+        .requestAttestation(challenge)
+        .context("Failed to request attestation")?;
     Ok(certificate)
 }