Associate user id with unlock token handle

Note: this assumes user-0 is always unlocked otherwise one would not
be able to access shared preference for user-0 when cold booted to lock
screen.

To test this CL, turn on the following system property

android.car.systemuser.headless=true

This build flag will make Android boot into a headless user-0 model and
user-0 will always be unlocked.

Bluetooth stack gets restarted every time switching user. This CL also
ensures the BLE trust agent service is started after bluetooth finishes
rebooting.

Current limitations:
- Unlock token works only if user sets password
- Unlock token is not activated till user finishes lock-unlock once

Bug: 78602296
Bug: 77854782
Test: unlock user by trust device on Mojave
Change-Id: Ifc2bf97593adbb77d518d6b11c06ea5234a4ebbd

5 files changed, 180 insertions, 106 deletions

diff --git a/TrustAgent/res/values/strings.xml b/TrustAgent/res/values/strings.xml
index d077262102..192b7e4b99 100644
--- a/TrustAgent/res/values/strings.xml
+++ b/TrustAgent/res/values/strings.xml
@@ -36,4 +36,6 @@
     <string name="start_advertising">Start Advertising</string>
     <string name="revoke_trust">Revoke Trust</string>
 
+    <string translatable="false" name="token_handle_shared_preferences">com.android.car.trust.TOKEN_HANDLE</string>
+
 </resources>
diff --git a/TrustAgent/src/com/android/car/trust/CarBleTrustAgent.java b/TrustAgent/src/com/android/car/trust/CarBleTrustAgent.java
index 227ea8919e..1dfbd504a1 100644
--- a/TrustAgent/src/com/android/car/trust/CarBleTrustAgent.java
+++ b/TrustAgent/src/com/android/car/trust/CarBleTrustAgent.java
@@ -16,27 +16,25 @@
 
 package com.android.car.trust;
 
-import android.bluetooth.BluetoothDevice;
-import android.bluetooth.BluetoothGattServer;
-import android.bluetooth.BluetoothGattServerCallback;
-import android.bluetooth.BluetoothManager;
+import android.annotation.Nullable;
+import android.app.ActivityManager;
+import android.app.UserSwitchObserver;
+import android.bluetooth.BluetoothAdapter;
 import android.car.trust.ICarTrustAgentBleService;
 import android.car.trust.ICarTrustAgentTokenRequestDelegate;
 import android.car.trust.ICarTrustAgentUnlockCallback;
+import android.content.BroadcastReceiver;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
+import android.content.IntentFilter;
 import android.content.ServiceConnection;
-import android.os.Handler;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.os.UserHandle;
-import android.os.UserManager;
 import android.service.trust.TrustAgentService;
 import android.util.Log;
 
-import java.util.concurrent.TimeUnit;
-
 /**
  * A BluetoothLE (BLE) based {@link TrustAgentService} that uses the escrow token unlock APIs. </p>
  *
@@ -49,39 +47,44 @@ public class CarBleTrustAgent extends TrustAgentService {
 
     private static final String TAG = CarBleTrustAgent.class.getSimpleName();
 
-    private static final long TRUST_DURATION_MS = TimeUnit.MINUTES.toMicros(5);
-    private static final long BLE_RETRY_MS = TimeUnit.SECONDS.toMillis(1);
-
-    private Handler mHandler;
-    private BluetoothManager mBluetoothManager;
-    private ICarTrustAgentBleService mCarTrustAgentBleService;
-    private boolean mCarTrustAgentBleServiceBound;
-
+    /**
+     * {@link CarTrustAgentBleService} will callback this function when it receives both
+     * handle and token.
+     */
     private final ICarTrustAgentUnlockCallback mUnlockCallback =
             new ICarTrustAgentUnlockCallback.Stub() {
         @Override
-        public void onUnlockDataReceived(byte[] token, long handle) {
-            UserManager um = (UserManager) getSystemService(Context.USER_SERVICE);
-            // TODO(b/77854782): get the actual user to unlock by token
-            UserHandle userHandle = getForegroundUserHandle();
-
-            Log.d(TAG, "About to unlock user. Handle: " + handle
-                    + " Time: " + System.currentTimeMillis());
-            unlockUserWithToken(handle, token, userHandle);
-
-            Log.d(TAG, "Attempted to unlock user, is user unlocked: "
-                    + um.isUserUnlocked(userHandle)
-                    + " Time: " + System.currentTimeMillis());
-            setManagingTrust(true);
+        public void onUnlockDataReceived(byte[] token, long handle) throws RemoteException {
+            UserHandle userHandle = getUserHandleByTokenHandle(handle);
+            if (userHandle == null) {
+                Log.e(TAG, "Unable to find user by token handle " + handle);
+                return;
+            }
 
-            if (um.isUserUnlocked(userHandle)) {
-                Log.d(TAG, getString(R.string.trust_granted_explanation));
-                grantTrust("Granting trust from escrow token",
-                        TRUST_DURATION_MS, FLAG_GRANT_TRUST_DISMISS_KEYGUARD);
+            int uid = userHandle.getIdentifier();
+            if (ActivityManager.getCurrentUser() != uid) {
+                Log.d(TAG, "Switch to user: " + uid);
+                // Try to unlock when user switch completes
+                ActivityManager.getService().registerUserSwitchObserver(
+                        getUserSwitchObserver(uid, token, handle), TAG);
+                ActivityManager am = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
+                am.switchUser(uid);
+            } else {
+                unlockUserInternally(uid, token, handle);
             }
         }
     };
 
+    /**
+     * Delegates the escrow token API calls from {@link CarTrustAgentBleService} to
+     * {@link TrustAgentService}. Due to the asynchronous nature, the results will be posted to
+     * {@link CarTrustAgentBleService} by the following calls
+     * <ul>
+     *     <li>{@link #onEscrowTokenAdded(byte[], long, UserHandle)}</li>
+     *     <li>{@link #onEscrowTokenRemoved(long, boolean)}</li>
+     *     <li>{@link #onEscrowTokenStateReceived(long, int)}</li>
+     * </ul>
+     */
     private final ICarTrustAgentTokenRequestDelegate mTokenRequestDelegate =
             new ICarTrustAgentTokenRequestDelegate.Stub() {
         @Override
@@ -105,6 +108,9 @@ public class CarBleTrustAgent extends TrustAgentService {
         }
     };
 
+    /**
+     * Service connection to {@link CarTrustAgentBleService}
+     */
     private final ServiceConnection mServiceConnection = new ServiceConnection() {
         @Override
         public void onServiceConnected(ComponentName name, IBinder service) {
@@ -114,7 +120,6 @@ public class CarBleTrustAgent extends TrustAgentService {
             try {
                 mCarTrustAgentBleService.registerUnlockCallback(mUnlockCallback);
                 mCarTrustAgentBleService.setTokenRequestDelegate(mTokenRequestDelegate);
-                maybeStartBleUnlockService();
             } catch (RemoteException e) {
                 Log.e(TAG, "Error registerUnlockCallback", e);
             }
@@ -122,10 +127,12 @@ public class CarBleTrustAgent extends TrustAgentService {
 
         @Override
         public void onServiceDisconnected(ComponentName name) {
+            Log.d(TAG, "CarTrustAgentBleService disconnected");
             if (mCarTrustAgentBleService != null) {
                 try {
                     mCarTrustAgentBleService.unregisterUnlockCallback(mUnlockCallback);
                     mCarTrustAgentBleService.setTokenRequestDelegate(null);
+                    mCarTrustAgentBleService.stopUnlockAdvertising();
                 } catch (RemoteException e) {
                     Log.e(TAG, "Error unregisterUnlockCallback", e);
                 }
@@ -135,45 +142,57 @@ public class CarBleTrustAgent extends TrustAgentService {
         }
     };
 
+    /**
+     * Receives the bluetooth state change broadcasts. Bluetooth is restarted when switching user,
+     * we need to ensure calling {@link ICarTrustAgentBleService#startUnlockAdvertising} after
+     * bluetooth is started.
+     */
+    private final BroadcastReceiver mBluetoothBroadcastReceiver = new BroadcastReceiver() {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            switch (intent.getAction()) {
+                case BluetoothAdapter.ACTION_STATE_CHANGED:
+                    onBluetoothStateChanged(intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, -1));
+                    break;
+            }
+        }
+    };
+
+    private ICarTrustAgentBleService mCarTrustAgentBleService;
+    private boolean mCarTrustAgentBleServiceBound;
+
+    /**
+     * TODO: Currently it relies on {@link #onDeviceLocked()} and {@link #onDeviceUnlocked()}
+     * callback, and these callbacks won't happen if the user has unlocked once.
+     */
+    private boolean mIsOnLockScreen;
+
     @Override
     public void onCreate() {
         super.onCreate();
-
-        Log.d(TAG, "Bluetooth trust agent starting up");
-        mHandler = new Handler();
-        mBluetoothManager = (BluetoothManager) getSystemService(BLUETOOTH_SERVICE);
-
-        // If the user is already unlocked, don't bother starting the BLE service.
-        UserManager um = (UserManager) getSystemService(Context.USER_SERVICE);
-        if (!um.isUserUnlocked(getForegroundUserHandle())) {
-            Log.d(TAG, "User locked, will now bind CarTrustAgentBleService");
-            Intent intent = new Intent(this, CarTrustAgentBleService.class);
-            bindService(intent, mServiceConnection, Context.BIND_AUTO_CREATE);
-        } else {
-            setManagingTrust(true);
-        }
+        setManagingTrust(true);
+        bindService(new Intent(this, CarTrustAgentBleService.class),
+                mServiceConnection, Context.BIND_AUTO_CREATE);
+        IntentFilter intentFilter = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
+        registerReceiver(mBluetoothBroadcastReceiver, intentFilter);
     }
 
     @Override
     public void onDestroy() {
         Log.d(TAG, "Car Trust agent shutting down");
-        mHandler.removeCallbacks(null);
-
-        // Unbind the service to avoid leaks from BLE stack.
         if (mCarTrustAgentBleServiceBound) {
             unbindService(mServiceConnection);
         }
+        unregisterReceiver(mBluetoothBroadcastReceiver);
         super.onDestroy();
     }
 
     @Override
     public void onDeviceLocked() {
         super.onDeviceLocked();
+        mIsOnLockScreen = true;
         if (mCarTrustAgentBleServiceBound) {
             try {
-                // Only one BLE advertising is allowed, ensure enrolment advertising is stopped
-                // before start unlock advertising.
-                mCarTrustAgentBleService.stopEnrolmentAdvertising();
                 mCarTrustAgentBleService.startUnlockAdvertising();
             } catch (RemoteException e) {
                 Log.e(TAG, "Error startUnlockAdvertising", e);
@@ -184,36 +203,47 @@ public class CarBleTrustAgent extends TrustAgentService {
     @Override
     public void onDeviceUnlocked() {
         super.onDeviceUnlocked();
+        mIsOnLockScreen = false;
         if (mCarTrustAgentBleServiceBound) {
             try {
-                // Only one BLE advertising is allowed, ensure unlock advertising is stopped.
                 mCarTrustAgentBleService.stopUnlockAdvertising();
             } catch (RemoteException e) {
                 Log.e(TAG, "Error stopUnlockAdvertising", e);
             }
         }
+        // Revoke trust right after to enable keyguard when switching user
+        revokeTrust();
     }
 
-    private void maybeStartBleUnlockService() {
-        Log.d(TAG, "Trying to open a Ble GATT server");
-        BluetoothGattServer gattServer = mBluetoothManager.openGattServer(
-                this, new BluetoothGattServerCallback() {
+    private UserSwitchObserver getUserSwitchObserver(int uid,
+            byte[] token, long handle) {
+        return new UserSwitchObserver() {
+            @Override
+            public void onUserSwitchComplete(int newUserId) throws RemoteException {
+                if (uid != newUserId) return;
+                unlockUserInternally(uid, token, handle);
+                ActivityManager.getService().unregisterUserSwitchObserver(this);
+            }
+
             @Override
-            public void onConnectionStateChange(BluetoothDevice device, int status, int newState) {
-                super.onConnectionStateChange(device, status, newState);
+            public void onLockedBootComplete(int newUserId) {
+                // ignored.
             }
-        });
+        };
+    }
+
+    private void unlockUserInternally(int uid, byte[] token, long handle) {
+        Log.d(TAG, "About to unlock user: " + uid);
+        unlockUserWithToken(handle, token, UserHandle.of(uid));
+        grantTrust("Granting trust from escrow token",
+                0, FLAG_GRANT_TRUST_DISMISS_KEYGUARD);
+    }
 
-        // The BLE stack is started up before the trust agent service, however Gatt capabilities
-        // might not be ready just yet. Keep trying until a GattServer can open up before proceeding
-        // to start the rest of the BLE services.
-        if (gattServer == null) {
-            Log.e(TAG, "Gatt not available, will try again...in " + BLE_RETRY_MS + "ms");
-            mHandler.postDelayed(this::maybeStartBleUnlockService, BLE_RETRY_MS);
-        } else {
-            mHandler.removeCallbacks(null);
-            gattServer.close();
-            Log.d(TAG, "GATT available, starting up UnlockService");
+    private void onBluetoothStateChanged(int state) {
+        Log.d(TAG, "onBluetoothStateChanged: " + state);
+        if ((state == BluetoothAdapter.STATE_ON || state == BluetoothAdapter.STATE_BLE_ON)
+                && mCarTrustAgentBleServiceBound
+                && mIsOnLockScreen) {
             try {
                 mCarTrustAgentBleService.startUnlockAdvertising();
             } catch (RemoteException e) {
@@ -259,12 +289,15 @@ public class CarBleTrustAgent extends TrustAgentService {
         }
     }
 
-    /**
-     * TODO(b/77854782): return the {@link UserHandle} of foreground user.
-     * CarBleTrustAgent itself runs as user-0
-     */
-    private UserHandle getForegroundUserHandle() {
-        Log.d(TAG, "getForegroundUserHandle for " + UserHandle.myUserId());
-        return UserHandle.of(UserHandle.myUserId());
+    private @Nullable UserHandle getUserHandleByTokenHandle(long tokenHandle) {
+        if (mCarTrustAgentBleServiceBound) {
+            try {
+                int userId = mCarTrustAgentBleService.getUserIdByEscrowTokenHandle(tokenHandle);
+                return userId < 0 ? null : UserHandle.of(userId);
+            } catch (RemoteException e) {
+                Log.e(TAG, "Error getUserHandleByTokenHandle");
+            }
+        }
+        return null;
     }
 }
diff --git a/TrustAgent/src/com/android/car/trust/CarEnrolmentActivity.java b/TrustAgent/src/com/android/car/trust/CarEnrolmentActivity.java
index d7160e3435..4b587d1419 100644
--- a/TrustAgent/src/com/android/car/trust/CarEnrolmentActivity.java
+++ b/TrustAgent/src/com/android/car/trust/CarEnrolmentActivity.java
@@ -46,13 +46,16 @@ public class CarEnrolmentActivity extends Activity {
     private static final String SP_HANDLE_KEY = "sp-test";
     private static final int FINE_LOCATION_REQUEST_CODE = 42;
 
+    /**
+     * Receives escrow token callbacks, registered on {@link CarTrustAgentBleService}
+     */
     private final ICarTrustAgentTokenResponseCallback mCarTrustAgentTokenResponseCallback =
             new ICarTrustAgentTokenResponseCallback.Stub() {
         @Override
         public void onEscrowTokenAdded(byte[] token, long handle, int uid) {
             runOnUiThread(() -> {
                 mPrefs.edit().putLong(SP_HANDLE_KEY, handle).apply();
-                Log.d(TAG, "stored new handle");
+                Log.d(TAG, "stored new handle for user: " + uid);
             });
 
             if (mBluetoothDevice == null) {
@@ -81,6 +84,9 @@ public class CarEnrolmentActivity extends Activity {
         }
     };
 
+    /**
+     * Receives BLE state change callbacks, registered on {@link CarTrustAgentBleService}
+     */
     private final ICarTrustAgentBleCallback mBleConnectionCallback =
             new ICarTrustAgentBleCallback.Stub() {
         @Override
@@ -108,6 +114,12 @@ public class CarEnrolmentActivity extends Activity {
         }
     };
 
+    /**
+     * {@link CarTrustAgentBleService} will callback this when receives enrolment data.
+     *
+     * Here is the place we can prompt to the user on HU whether or not to add this
+     * {@link #mBluetoothDevice} as a trust device.
+     */
     private final ICarTrustAgentEnrolmentCallback mEnrolmentCallback =
             new ICarTrustAgentEnrolmentCallback.Stub() {
         @Override
@@ -121,6 +133,9 @@ public class CarEnrolmentActivity extends Activity {
         }
     };
 
+    /**
+     * Service connection to {@link CarTrustAgentBleService}
+     */
     private final ServiceConnection mServiceConnection = new ServiceConnection() {
         @Override
         public void onServiceConnected(ComponentName name, IBinder service) {
@@ -135,6 +150,7 @@ public class CarEnrolmentActivity extends Activity {
             } catch (RemoteException e) {
                 Log.e(TAG, "Error startEnrolmentAdvertising", e);
             }
+            checkTokenHandle();
         }
 
         @Override
@@ -169,8 +185,10 @@ public class CarEnrolmentActivity extends Activity {
         mPrefs = PreferenceManager.getDefaultSharedPreferences(this /* context */);
 
         findViewById(R.id.start_button).setOnClickListener((view) -> {
-            Intent bindIntent = new Intent(this, CarTrustAgentBleService.class);
-            bindService(bindIntent, mServiceConnection, Context.BIND_AUTO_CREATE);
+            if (!mCarTrustAgentBleServiceBound) {
+                Intent bindIntent = new Intent(this, CarTrustAgentBleService.class);
+                bindService(bindIntent, mServiceConnection, Context.BIND_AUTO_CREATE);
+            }
         });
 
         findViewById(R.id.revoke_trust_button).setOnClickListener((view) -> {
@@ -193,33 +211,17 @@ public class CarEnrolmentActivity extends Activity {
             requestPermissions(
                     new String[] { android.Manifest.permission.ACCESS_FINE_LOCATION },
                     FINE_LOCATION_REQUEST_CODE);
-        } else {
-            long tokenHandle = getTokenHandle();
-            if (tokenHandle != -1) {
-                Log.d(TAG, "onResume, checking handle active: " + tokenHandle);
-                if (mCarTrustAgentBleServiceBound) {
-                    try {
-                        // Due to the asynchronous nature of isEscrowTokenActive in
-                        // TrustAgentService, query result will be delivered via
-                        // {@link #mCarTrustAgentTokenResponseCallback}
-                        mCarTrustAgentBleService.isEscrowTokenActive(tokenHandle,
-                                UserHandle.myUserId());
-                    } catch (RemoteException e) {
-                        Log.e(TAG, "Error isEscrowTokenActive", e);
-                    }
-                }
-            } else {
-                appendOutputText("No handles found");
-            }
         }
     }
 
     @Override
-    protected void onDestroy() {
+    protected void onStop() {
+        super.onStop();
+
         if (mCarTrustAgentBleServiceBound) {
             unbindService(mServiceConnection);
+            mCarTrustAgentBleServiceBound = false;
         }
-        super.onDestroy();
     }
 
     private void appendOutputText(final String text) {
@@ -234,7 +236,23 @@ public class CarEnrolmentActivity extends Activity {
         mCarTrustAgentBleService.addEscrowToken(token, UserHandle.myUserId());
     }
 
-    private long getTokenHandle() {
-        return mPrefs.getLong(SP_HANDLE_KEY, -1);
+    private void checkTokenHandle() {
+        long tokenHandle = mPrefs.getLong(SP_HANDLE_KEY, -1);
+        if (tokenHandle != -1) {
+            Log.d(TAG, "Checking handle active: " + tokenHandle);
+            if (mCarTrustAgentBleServiceBound) {
+                try {
+                    // Due to the asynchronous nature of isEscrowTokenActive in
+                    // TrustAgentService, query result will be delivered via
+                    // {@link #mCarTrustAgentTokenResponseCallback}
+                    mCarTrustAgentBleService.isEscrowTokenActive(tokenHandle,
+                            UserHandle.myUserId());
+                } catch (RemoteException e) {
+                    Log.e(TAG, "Error isEscrowTokenActive", e);
+                }
+            }
+        } else {
+            appendOutputText("No handles found");
+        }
     }
 }
diff --git a/TrustAgent/src/com/android/car/trust/CarTrustAgentBleService.java b/TrustAgent/src/com/android/car/trust/CarTrustAgentBleService.java
index f8ba90f36a..2cc2080089 100644
--- a/TrustAgent/src/com/android/car/trust/CarTrustAgentBleService.java
+++ b/TrustAgent/src/com/android/car/trust/CarTrustAgentBleService.java
@@ -25,6 +25,7 @@ import android.car.trust.ICarTrustAgentTokenRequestDelegate;
 import android.car.trust.ICarTrustAgentTokenResponseCallback;
 import android.car.trust.ICarTrustAgentUnlockCallback;
 import android.content.Intent;
+import android.content.SharedPreferences;
 import android.os.IBinder;
 import android.os.ParcelUuid;
 import android.os.RemoteCallbackList;
@@ -62,6 +63,8 @@ public class CarTrustAgentBleService extends SimpleBleServer {
     private byte[] mCurrentUnlockToken;
     private Long mCurrentUnlockHandle;
 
+    private SharedPreferences mTokenHandleSharedPreferences;
+
     @Override
     public void onCreate() {
         super.onCreate();
@@ -72,6 +75,10 @@ public class CarTrustAgentBleService extends SimpleBleServer {
 
         setupEnrolmentBleServer();
         setupUnlockBleServer();
+
+        mTokenHandleSharedPreferences = getSharedPreferences(
+                getString(R.string.token_handle_shared_preferences),
+                MODE_PRIVATE);
     }
 
     @Override
@@ -260,8 +267,8 @@ public class CarTrustAgentBleService extends SimpleBleServer {
 
         @Override
         public void startEnrolmentAdvertising() {
-            Log.d(TAG, "startEnrolmentAdvertising");
             stopUnlockAdvertising();
+            Log.d(TAG, "startEnrolmentAdvertising");
             startAdvertising(mEnrolmentUuid, mEnrolmentGattServer);
         }
 
@@ -290,8 +297,8 @@ public class CarTrustAgentBleService extends SimpleBleServer {
 
         @Override
         public void startUnlockAdvertising() {
-            Log.d(TAG, "startUnlockAdvertising");
             stopEnrolmentAdvertising();
+            Log.d(TAG, "startUnlockAdvertising");
             startAdvertising(mUnlockUuid, mUnlockGattServer);
         }
 
@@ -353,6 +360,9 @@ public class CarTrustAgentBleService extends SimpleBleServer {
         public void onEscrowTokenAdded(byte[] token, long handle, int uid)
                 throws RemoteException {
             Log.d(TAG, "onEscrowTokenAdded handle:" + handle + " uid:" + uid);
+            mTokenHandleSharedPreferences.edit()
+                    .putInt(String.valueOf(handle), uid)
+                    .apply();
             if (mTokenResponseCallback != null) {
                 mTokenResponseCallback.onEscrowTokenAdded(token, handle, uid);
             }
@@ -361,6 +371,9 @@ public class CarTrustAgentBleService extends SimpleBleServer {
         @Override
         public void onEscrowTokenRemoved(long handle, boolean successful) throws RemoteException {
             Log.d(TAG, "onEscrowTokenRemoved handle:" + handle);
+            mTokenHandleSharedPreferences.edit()
+                    .remove(String.valueOf(handle))
+                    .apply();
             if (mTokenResponseCallback != null) {
                 mTokenResponseCallback.onEscrowTokenRemoved(handle, successful);
             }
@@ -373,5 +386,10 @@ public class CarTrustAgentBleService extends SimpleBleServer {
                 mTokenResponseCallback.onEscrowTokenActiveStateChanged(handle, active);
             }
         }
+
+        @Override
+        public int getUserIdByEscrowTokenHandle(long tokenHandle) {
+            return mTokenHandleSharedPreferences.getInt(String.valueOf(tokenHandle), -1);
+        }
     }
 }
diff --git a/car-lib/src/android/car/trust/ICarTrustAgentBleService.aidl b/car-lib/src/android/car/trust/ICarTrustAgentBleService.aidl
index 8b50fd379a..4dec6a0a43 100644
--- a/car-lib/src/android/car/trust/ICarTrustAgentBleService.aidl
+++ b/car-lib/src/android/car/trust/ICarTrustAgentBleService.aidl
@@ -58,4 +58,7 @@ interface ICarTrustAgentBleService {
     void onEscrowTokenAdded(in byte[] token, long handle, int uid);
     void onEscrowTokenRemoved(long handle, boolean successful);
     void onEscrowTokenActiveStateChanged(long handle, boolean active);
+
+    /** Management */
+    int getUserIdByEscrowTokenHandle(long tokenHandle);
 }