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Commit 0e8a7db6 authored by Philip P. Moltmann's avatar Philip P. Moltmann
Browse files

Clear identity before calling deeper into USB code 

This is needed as deeper in the code we call UsbAccessory.getSerial
which behaves differently depending on the caller. I.e. we have to make
sure to have the system server identity when we call this methods.

Fixes: 117547676
Test: - Started Android Auto
      - CtsVerifier USB Device and USB Accessory tests

Change-Id: I6d752ad5d2ff058dadf1e27e41247153c7db5ee6
parent 803a5249

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

+3 −3
Original line number Diff line number Diff line
@@ -50,7 +50,6 @@ import android.hardware.usb.gadget.V1_0.Status; 
import android.hidl.manager.V1_0.IServiceManager;

import android.hidl.manager.V1_0.IServiceNotification;

import android.os.BatteryManager;

import android.os.Binder;

import android.os.Environment;

import android.os.FileUtils;

import android.os.Handler;
@@ -1982,9 +1981,10 @@ public class UsbDeviceManager implements ActivityTaskManagerInternal.ScreenObser 
     * opens the currently attached USB accessory.

     *

     * @param accessory accessory to be openened.

     * @param uid Uid of the caller

     */

    public ParcelFileDescriptor openAccessory(UsbAccessory accessory,

            UsbUserSettingsManager settings) {

            UsbUserSettingsManager settings, int uid) {

        UsbAccessory currentAccessory = mHandler.getCurrentAccessory();

        if (currentAccessory == null) {

            throw new IllegalArgumentException("no accessory attached");
@@ -1995,7 +1995,7 @@ public class UsbDeviceManager implements ActivityTaskManagerInternal.ScreenObser 
                    + currentAccessory;

            throw new IllegalArgumentException(error);

        }

        settings.checkPermission(accessory, Binder.getCallingUid());

        settings.checkPermission(accessory, uid);

        return nativeOpenAccessory();

    }

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

+31 −39
Original line number Diff line number Diff line
@@ -230,43 +230,30 @@ public class UsbService extends IUsbManager.Stub { 
        }

    }



    /**

     * Check if the calling user is in the same profile group as the {@link #mCurrentUserId

     * current user}.

     *

     * @return Iff the caller is in the current user's profile group

     */

    @GuardedBy("mLock")

    private boolean isCallerInCurrentUserProfileGroupLocked() {

        int userIdInt = UserHandle.getCallingUserId();



        long ident = clearCallingIdentity();

        try {

            return mUserManager.isSameProfileGroup(userIdInt, mCurrentUserId);

        } finally {

            restoreCallingIdentity(ident);

        }

    }



    /* Opens the specified USB device (host mode) */

    @Override

    public ParcelFileDescriptor openDevice(String deviceName, String packageName) {

        ParcelFileDescriptor fd = null;



        if (mHostManager != null) {

            synchronized (mLock) {

            if (deviceName != null) {

                    int userIdInt = UserHandle.getCallingUserId();

                    boolean isCurrentUser = isCallerInCurrentUserProfileGroupLocked();

                int uid = Binder.getCallingUid();

                int user = UserHandle.getUserId(uid);



                    if (isCurrentUser) {

                        fd = mHostManager.openDevice(deviceName, getSettingsForUser(userIdInt),

                                packageName, Binder.getCallingUid());

                long ident = clearCallingIdentity();

                try {

                    synchronized (mLock) {

                        if (mUserManager.isSameProfileGroup(user, mCurrentUserId)) {

                            fd = mHostManager.openDevice(deviceName, getSettingsForUser(user),

                                    packageName, uid);

                        } else {

                        Slog.w(TAG, "Cannot open " + deviceName + " for user " + userIdInt +

                               " as user is not active.");

                            Slog.w(TAG, "Cannot open " + deviceName + " for user " + user

                                    + " as user is not active.");

                        }

                    }

                } finally {

                    restoreCallingIdentity(ident);

                }

            }

        }
@@ -287,18 +274,23 @@ public class UsbService extends IUsbManager.Stub { 
    @Override

    public ParcelFileDescriptor openAccessory(UsbAccessory accessory) {

        if (mDeviceManager != null) {

            int userIdInt = UserHandle.getCallingUserId();

            int uid = Binder.getCallingUid();

            int user = UserHandle.getUserId(uid);



            long ident = clearCallingIdentity();

            try {

                synchronized (mLock) {

                boolean isCurrentUser = isCallerInCurrentUserProfileGroupLocked();



                if (isCurrentUser) {

                    return mDeviceManager.openAccessory(accessory, getSettingsForUser(userIdInt));

                    if (mUserManager.isSameProfileGroup(user, mCurrentUserId)) {

                        return mDeviceManager.openAccessory(accessory, getSettingsForUser(user),

                                uid);

                    } else {

                    Slog.w(TAG, "Cannot open " + accessory + " for user " + userIdInt +

                            " as user is not active.");

                        Slog.w(TAG, "Cannot open " + accessory + " for user " + user

                                + " as user is not active.");

                    }

                }

            } finally {

                restoreCallingIdentity(ident);

            }

        }



        return null;