From 5201f1e61cbeaf3c967840c4200da76d7a3b85dd Mon Sep 17 00:00:00 2001 From: "Philip P. Moltmann" Date: Fri, 30 Sep 2016 14:58:27 -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 | 19 +++++++++++++++++-- .../java/android/hardware/usb/UsbManager.java | 2 +- media/java/android/mtp/MtpDevice.java | 14 +++++++++++++- .../java/com/android/server/MountService.java | 19 ++++++++++++++----- 4 files changed, 45 insertions(+), 9 deletions(-) diff --git a/core/java/android/hardware/usb/UsbDeviceConnection.java b/core/java/android/hardware/usb/UsbDeviceConnection.java index c062b3a311526..893b9541ff3d2 100644 --- a/core/java/android/hardware/usb/UsbDeviceConnection.java +++ b/core/java/android/hardware/usb/UsbDeviceConnection.java @@ -16,8 +16,10 @@ package android.hardware.usb; +import android.annotation.NonNull; +import android.annotation.Nullable; +import android.content.Context; import android.os.ParcelFileDescriptor; - import java.io.FileDescriptor; @@ -31,6 +33,8 @@ public class UsbDeviceConnection { private final UsbDevice mDevice; + private Context mContext; + // used by the JNI code private long mNativeContext; @@ -42,10 +46,21 @@ 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(); + return native_open(name, pfd.getFileDescriptor()); } + /** + * @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 629db06a30e37..cb2720ab98489 100644 --- a/core/java/android/hardware/usb/UsbManager.java +++ b/core/java/android/hardware/usb/UsbManager.java @@ -330,7 +330,7 @@ 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 4082778986c62..e7ea1a5a12cff 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; @@ -62,7 +64,17 @@ public final class MtpDevice { * @return true if the device was successfully opened. */ public boolean open(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 0023e4bef77c7..8430a0b299060 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() {