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Commit f934d17b authored by Esteban Talavera's avatar Esteban Talavera
Browse files

Restart USB stack if data transfer becomes unavailable 

If DISALLOW_USB_FILE_TRANSFER is set while the device is
connected via USB and data transfer is enabled, restart
the USB stack to make sure that data cannot be transferred any more

Fix: 34487750
Bug: 34054991

Test: Checked that files cannot be transferred any more as soon as the user restriction is set
Test: cts-tradefed run cts-dev --module DevicePolicyManager --test com.android.cts.devicepolicy.UserRestrictionsTest

Change-Id: I129c226e57da2d0be356f93436b36b3303cb604c
parent bc44678f

services/usb/java/com/android/server/usb/UsbDeviceManager.java

+16 −8
Original line number Diff line number Diff line
@@ -554,7 +554,7 @@ public class UsbDeviceManager { 
                boolean usbDataUnlocked) {

            if (DEBUG) {

                Slog.d(TAG, "setEnabledFunctions functions=" + functions + ", "

                        + "forceRestart=" + forceRestart);

                        + "forceRestart=" + forceRestart + ", usbDataUnlocked=" + usbDataUnlocked);

            }



            if (usbDataUnlocked != mUsbDataUnlocked) {
@@ -878,7 +878,12 @@ public class UsbDeviceManager { 
                    setEnabledFunctions(functions, false, msg.arg1 == 1);

                    break;

                case MSG_UPDATE_USER_RESTRICTIONS:

                    setEnabledFunctions(mCurrentFunctions, false, mUsbDataUnlocked);

                    // Restart the USB stack if USB transfer is enabled but no longer allowed.

                    final boolean forceRestart = mUsbDataUnlocked

                            && isUsbDataTransferActive()

                            && !isUsbTransferAllowed();

                    setEnabledFunctions(

                            mCurrentFunctions, forceRestart, mUsbDataUnlocked && !forceRestart);

                    break;

                case MSG_SYSTEM_READY:

                    updateUsbNotification();
@@ -902,12 +907,10 @@ public class UsbDeviceManager { 
                case MSG_USER_SWITCHED: {

                    if (mCurrentUser != msg.arg1) {

                        // Restart the USB stack and re-apply user restrictions for MTP or PTP.

                        final boolean active = UsbManager.containsFunction(mCurrentFunctions,

                                UsbManager.USB_FUNCTION_MTP)

                                || UsbManager.containsFunction(mCurrentFunctions,

                                UsbManager.USB_FUNCTION_PTP);

                        if (mUsbDataUnlocked && active && mCurrentUser != UserHandle.USER_NULL) {

                            Slog.v(TAG, "Current user switched to " + mCurrentUser

                        if (mUsbDataUnlocked

                                && isUsbDataTransferActive()

                                && mCurrentUser != UserHandle.USER_NULL) {

                            Slog.v(TAG, "Current user switched to " + msg.arg1

                                    + "; resetting USB host stack for MTP or PTP");

                            // avoid leaking sensitive data from previous user

                            setEnabledFunctions(mCurrentFunctions, true, false);
@@ -928,6 +931,11 @@ public class UsbDeviceManager { 
            }

        }



        private boolean isUsbDataTransferActive() {

            return UsbManager.containsFunction(mCurrentFunctions, UsbManager.USB_FUNCTION_MTP)

                    || UsbManager.containsFunction(mCurrentFunctions, UsbManager.USB_FUNCTION_PTP);

        }



        public UsbAccessory getCurrentAccessory() {

            return mCurrentAccessory;

        }