Gradually increase the level of authentication on failed GATT operations.

When lower layer returns insufficient authentication or insufficient
encryption on various GATT operations, gradually retry with increased
authentication level first to AUTHENTICATION_NO_MITM, then
AUTHENTICATION_MITM.

Change-Id: I68335cf7451aeaf49c227d604f69cb329d117d08

diff --git a/core/java/android/bluetooth/BluetoothGatt.java b/core/java/android/bluetooth/BluetoothGatt.java
index 552c8d3..0eca4d6 100644 (file)
--- a/core/java/android/bluetooth/BluetoothGatt.java
+++ b/core/java/android/bluetooth/BluetoothGatt.java
@@ -44,14 +44,18 @@ public final class BluetoothGatt implements BluetoothProfile {
     private IBluetoothGatt mService;
     private BluetoothGattCallback mCallback;
     private int mClientIf;
-    private boolean mAuthRetry = false;
     private BluetoothDevice mDevice;
     private boolean mAutoConnect;
+    private int mAuthRetryState;
     private int mConnState;
     private final Object mStateLock = new Object();
     private Boolean mDeviceBusy = false;
     private int mTransport;
 
+    private static final int AUTH_RETRY_STATE_IDLE = 0;
+    private static final int AUTH_RETRY_STATE_NO_MITM = 1;
+    private static final int AUTH_RETRY_STATE_MITM = 2;
+
     private static final int CONN_STATE_IDLE = 0;
     private static final int CONN_STATE_CONNECTING = 1;
     private static final int CONN_STATE_CONNECTED = 2;
@@ -262,17 +266,19 @@ public final class BluetoothGatt implements BluetoothProfile {
 
                 if ((status == GATT_INSUFFICIENT_AUTHENTICATION
                   || status == GATT_INSUFFICIENT_ENCRYPTION)
-                  && mAuthRetry == false) {
+                  && (mAuthRetryState != AUTH_RETRY_STATE_MITM)) {
                     try {
-                        mAuthRetry = true;
-                        mService.readCharacteristic(mClientIf, address, handle, AUTHENTICATION_MITM);
+                        final int authReq = (mAuthRetryState == AUTH_RETRY_STATE_IDLE) ?
+                                AUTHENTICATION_NO_MITM : AUTHENTICATION_MITM;
+                        mService.readCharacteristic(mClientIf, address, handle, authReq);
+                        mAuthRetryState++;
                         return;
                     } catch (RemoteException e) {
                         Log.e(TAG,"",e);
                     }
                 }
 
-                mAuthRetry = false;
+                mAuthRetryState = AUTH_RETRY_STATE_IDLE;
 
                 BluetoothGattCharacteristic characteristic = getCharacteristicById(mDevice, handle);
                 if (characteristic == null) {
@@ -311,19 +317,20 @@ public final class BluetoothGatt implements BluetoothProfile {
 
                 if ((status == GATT_INSUFFICIENT_AUTHENTICATION
                   || status == GATT_INSUFFICIENT_ENCRYPTION)
-                  && mAuthRetry == false) {
+                  && (mAuthRetryState != AUTH_RETRY_STATE_MITM)) {
                     try {
-                        mAuthRetry = true;
+                        final int authReq = (mAuthRetryState == AUTH_RETRY_STATE_IDLE) ?
+                                AUTHENTICATION_NO_MITM : AUTHENTICATION_MITM;
                         mService.writeCharacteristic(mClientIf, address, handle,
-                            characteristic.getWriteType(), AUTHENTICATION_MITM,
-                            characteristic.getValue());
+                            characteristic.getWriteType(), authReq, characteristic.getValue());
+                        mAuthRetryState++;
                         return;
                     } catch (RemoteException e) {
                         Log.e(TAG,"",e);
                     }
                 }
 
-                mAuthRetry = false;
+                mAuthRetryState = AUTH_RETRY_STATE_IDLE;
 
                 try {
                     mCallback.onCharacteristicWrite(BluetoothGatt.this, characteristic, status);
@@ -378,17 +385,19 @@ public final class BluetoothGatt implements BluetoothProfile {
 
                 if ((status == GATT_INSUFFICIENT_AUTHENTICATION
                   || status == GATT_INSUFFICIENT_ENCRYPTION)
-                  && mAuthRetry == false) {
+                  && (mAuthRetryState != AUTH_RETRY_STATE_MITM)) {
                     try {
-                        mAuthRetry = true;
-                        mService.readDescriptor(mClientIf, address, handle, AUTHENTICATION_MITM);
+                        final int authReq = (mAuthRetryState == AUTH_RETRY_STATE_IDLE) ?
+                                AUTHENTICATION_NO_MITM : AUTHENTICATION_MITM;
+                        mService.readDescriptor(mClientIf, address, handle, authReq);
+                        mAuthRetryState++;
                         return;
                     } catch (RemoteException e) {
                         Log.e(TAG,"",e);
                     }
                 }
 
-                mAuthRetry = true;
+                mAuthRetryState = AUTH_RETRY_STATE_IDLE;
 
                 try {
                     mCallback.onDescriptorRead(BluetoothGatt.this, descriptor, status);
@@ -417,19 +426,21 @@ public final class BluetoothGatt implements BluetoothProfile {
 
                 if ((status == GATT_INSUFFICIENT_AUTHENTICATION
                   || status == GATT_INSUFFICIENT_ENCRYPTION)
-                  && mAuthRetry == false) {
+                  && (mAuthRetryState != AUTH_RETRY_STATE_MITM)) {
                     try {
-                        mAuthRetry = true;
+                        final int authReq = (mAuthRetryState == AUTH_RETRY_STATE_IDLE) ?
+                                AUTHENTICATION_NO_MITM : AUTHENTICATION_MITM;
                         mService.writeDescriptor(mClientIf, address, handle,
                             BluetoothGattCharacteristic.WRITE_TYPE_DEFAULT,
-                            AUTHENTICATION_MITM, descriptor.getValue());
+                            authReq, descriptor.getValue());
+                        mAuthRetryState++;
                         return;
                     } catch (RemoteException e) {
                         Log.e(TAG,"",e);
                     }
                 }
 
-                mAuthRetry = false;
+                mAuthRetryState = AUTH_RETRY_STATE_IDLE;
 
                 try {
                     mCallback.onDescriptorWrite(BluetoothGatt.this, descriptor, status);
@@ -503,6 +514,7 @@ public final class BluetoothGatt implements BluetoothProfile {
         mServices = new ArrayList<BluetoothGattService>();
 
         mConnState = CONN_STATE_IDLE;
+        mAuthRetryState = AUTH_RETRY_STATE_IDLE;
     }
 
     /**
@@ -516,6 +528,7 @@ public final class BluetoothGatt implements BluetoothProfile {
 
         unregisterApp();
         mConnState = CONN_STATE_CLOSED;
+        mAuthRetryState = AUTH_RETRY_STATE_IDLE;
     }
 
     /**