From ec3cbb2a66cfd4923b15f7eee0e78bfddb517997 Mon Sep 17 00:00:00 2001 From: "Philip P. Moltmann" Date: Wed, 14 Sep 2016 13:24:52 -0700 Subject: [PATCH] Do not access MTP devices when disabled. The USB data transfer is disabled we should not allow access MTP devices (e.g. usb sticks). We have two ways of accessing them: Either by mounting them or by creating a MTPDevice in an app. Of course an app could implement implement their own MTPDevice implementation. In this case we cannot enforce the policy without completely suppressing all MTP USB devices which would be too restrictive. Note: When the policy is set we do _not_ disconnect already connected MTP devices Fixes: 31472955 Change-Id: I6080c48c49657102774b2b3b4d89ff030245a266 --- .../hardware/usb/UsbDeviceConnection.java | 17 ++++++++++++++++- .../java/android/hardware/usb/UsbManager.java | 2 +- media/java/android/mtp/MtpDevice.java | 14 +++++++++++++- .../java/com/android/server/MountService.java | 19 ++++++++++++++----- 4 files changed, 44 insertions(+), 8 deletions(-) diff --git a/core/java/android/hardware/usb/UsbDeviceConnection.java b/core/java/android/hardware/usb/UsbDeviceConnection.java index 6f3993578d84e..1f09a9aa7848c 100644 --- a/core/java/android/hardware/usb/UsbDeviceConnection.java +++ b/core/java/android/hardware/usb/UsbDeviceConnection.java @@ -16,7 +16,10 @@ package android.hardware.usb; +import android.annotation.NonNull; +import android.annotation.Nullable; import android.annotation.SystemApi; +import android.content.Context; import android.os.ParcelFileDescriptor; import dalvik.system.CloseGuard; @@ -33,6 +36,8 @@ public class UsbDeviceConnection { private final UsbDevice mDevice; + private Context mContext; + // used by the JNI code private long mNativeContext; @@ -46,7 +51,8 @@ public class UsbDeviceConnection { mDevice = device; } - /* package */ boolean open(String name, ParcelFileDescriptor pfd) { + /* package */ boolean open(String name, ParcelFileDescriptor pfd, @NonNull Context context) { + mContext = context.getApplicationContext(); boolean wasOpened = native_open(name, pfd.getFileDescriptor()); if (wasOpened) { @@ -56,6 +62,15 @@ public class UsbDeviceConnection { return wasOpened; } + /** + * @return The application context the connection was created for. + * + * @hide + */ + public @Nullable Context getContext() { + return mContext; + } + /** * Releases all system resources related to the device. * Once the object is closed it cannot be used again. diff --git a/core/java/android/hardware/usb/UsbManager.java b/core/java/android/hardware/usb/UsbManager.java index df4785ee45d96..1d20c78cdc97c 100644 --- a/core/java/android/hardware/usb/UsbManager.java +++ b/core/java/android/hardware/usb/UsbManager.java @@ -332,7 +332,7 @@ public class UsbManager { ParcelFileDescriptor pfd = mService.openDevice(deviceName); if (pfd != null) { UsbDeviceConnection connection = new UsbDeviceConnection(device); - boolean result = connection.open(deviceName, pfd); + boolean result = connection.open(deviceName, pfd, mContext); pfd.close(); if (result) { return connection; diff --git a/media/java/android/mtp/MtpDevice.java b/media/java/android/mtp/MtpDevice.java index 6970cffa2c6e0..4e7551c1e855e 100644 --- a/media/java/android/mtp/MtpDevice.java +++ b/media/java/android/mtp/MtpDevice.java @@ -18,11 +18,13 @@ package android.mtp; import android.annotation.NonNull; import android.annotation.Nullable; +import android.content.Context; import android.hardware.usb.UsbDevice; import android.hardware.usb.UsbDeviceConnection; import android.os.CancellationSignal; import android.os.ParcelFileDescriptor; +import android.os.UserManager; import com.android.internal.util.Preconditions; import java.io.IOException; @@ -63,7 +65,17 @@ public final class MtpDevice { * @return true if the device was successfully opened. */ public boolean open(@NonNull UsbDeviceConnection connection) { - boolean result = native_open(mDevice.getDeviceName(), connection.getFileDescriptor()); + boolean result = false; + + Context context = connection.getContext(); + if (context != null) { + UserManager userManager = (UserManager) context.getSystemService(Context.USER_SERVICE); + + if (!userManager.hasUserRestriction(UserManager.DISALLOW_USB_FILE_TRANSFER)) { + result = native_open(mDevice.getDeviceName(), connection.getFileDescriptor()); + } + } + if (!result) { connection.close(); } diff --git a/services/core/java/com/android/server/MountService.java b/services/core/java/com/android/server/MountService.java index dc48cea98e6ce..b9a483138520c 100644 --- a/services/core/java/com/android/server/MountService.java +++ b/services/core/java/com/android/server/MountService.java @@ -1437,13 +1437,22 @@ class MountService extends IMountService.Stub * Decide if volume is mountable per device policies. */ private boolean isMountDisallowed(VolumeInfo vol) { - if (vol.type == VolumeInfo.TYPE_PUBLIC || vol.type == VolumeInfo.TYPE_PRIVATE) { - final UserManager userManager = mContext.getSystemService(UserManager.class); - return userManager.hasUserRestriction(UserManager.DISALLOW_MOUNT_PHYSICAL_MEDIA, + UserManager userManager = mContext.getSystemService(UserManager.class); + + boolean isUsbRestricted = false; + if (vol.disk != null && vol.disk.isUsb()) { + isUsbRestricted = userManager.hasUserRestriction(UserManager.DISALLOW_USB_FILE_TRANSFER, Binder.getCallingUserHandle()); - } else { - return false; } + + boolean isTypeRestricted = false; + if (vol.type == VolumeInfo.TYPE_PUBLIC || vol.type == VolumeInfo.TYPE_PRIVATE) { + isTypeRestricted = userManager + .hasUserRestriction(UserManager.DISALLOW_MOUNT_PHYSICAL_MEDIA, + Binder.getCallingUserHandle()); + } + + return isUsbRestricted || isTypeRestricted; } private void enforceAdminUser() {