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Commit 3a062a67 authored by Jeff Sharkey's avatar Jeff Sharkey
Browse files

Public volumes belong to a single user. 

When a public (vfat) device is inserted, it's strongly associated
with the current foreground user, and no other users should be able
to access it, since otherwise that would be a cross-user data leak.

To use the device under a different user, switch users and then
eject/remount the device.

Test: verified user isolation of USB drive
Bug: 32523490
Change-Id: I590c791996f1fea8d78f625dc942d149f1f41614
parent aa394dd4

packages/ExternalStorageProvider/src/com/android/externalstorage/ExternalStorageProvider.java

+2 −1
Original line number Diff line number Diff line
@@ -134,7 +134,8 @@ public class ExternalStorageProvider extends DocumentsProvider { 
                    final VolumeInfo privateVol = mStorageManager.findPrivateForEmulated(volume);

                    title = mStorageManager.getBestVolumeDescription(privateVol);

                }

            } else if (volume.getType() == VolumeInfo.TYPE_PUBLIC) {

            } else if (volume.getType() == VolumeInfo.TYPE_PUBLIC

                    && volume.getMountUserId() == userId) {

                rootId = volume.getFsUuid();

                title = mStorageManager.getBestVolumeDescription(volume);

            } else {

services/core/java/com/android/server/MountService.java

+8 −1
Original line number Diff line number Diff line
@@ -168,6 +168,11 @@ class MountService extends IMountService.Stub 
            }

        }



        @Override

        public void onSwitchUser(int userHandle) {

            mMountService.mCurrentUserId = userHandle;

        }



        @Override

        public void onStartUser(int userHandle) {

            mMountService.onStartUser(userHandle);
@@ -307,6 +312,8 @@ class MountService extends IMountService.Stub 
    @GuardedBy("mLock")

    private String mMoveTargetUuid;



    private volatile int mCurrentUserId = UserHandle.USER_OWNER;



    private VolumeInfo findVolumeByIdOrThrow(String id) {

        synchronized (mLock) {

            final VolumeInfo vol = mVolumes.get(id);
@@ -1183,7 +1190,7 @@ class MountService extends IMountService.Stub 
                vol.mountFlags |= VolumeInfo.MOUNT_FLAG_VISIBLE;

            }



            vol.mountUserId = UserHandle.USER_OWNER;

            vol.mountUserId = mCurrentUserId;

            mHandler.obtainMessage(H_VOLUME_MOUNT, vol).sendToTarget();



        } else if (vol.type == VolumeInfo.TYPE_PRIVATE) {