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Commit 8624560d authored by Cheng Shi's avatar Cheng Shi
Browse files

Fix the problem that system apps cannot drag 

If an app with a uid of Process.SYSTEM_UID calls view.startDragAndDrop, IllegalStateException will be thrown in Session.performDrag, which makes the drag-and-drop feature unavailable in this app.
And we don't need this check either, because validateAndResolveDragMimeTypeExtras and validateDragFlags are indeed called before Binder.clearCallingIdentity.

Bug: 245626682

Change-Id: I1c27287e51a956284dae0f61bfa0cac14dd28a27
parent 3312d073

services/core/java/com/android/server/wm/Session.java

+2 −9
Original line number Diff line number Diff line
@@ -322,7 +322,7 @@ class Session extends IWindowSession.Stub implements IBinder.DeathRecipient { 
        final int callingPid = Binder.getCallingPid();

        // Validate and resolve ClipDescription data before clearing the calling identity

        validateAndResolveDragMimeTypeExtras(data, callingUid, callingPid, mPackageName);

        validateDragFlags(flags, callingUid);

        validateDragFlags(flags);

        final long ident = Binder.clearCallingIdentity();

        try {

            return mDragDropController.performDrag(mPid, mUid, window, flags, surface, touchSource,
@@ -347,11 +347,7 @@ class Session extends IWindowSession.Stub implements IBinder.DeathRecipient { 
     * Validates the given drag flags.

     */

    @VisibleForTesting

    void validateDragFlags(int flags, int callingUid) {

        if (callingUid == Process.SYSTEM_UID) {

            throw new IllegalStateException("Need to validate before calling identify is cleared");

        }



    void validateDragFlags(int flags) {

        if ((flags & View.DRAG_FLAG_REQUEST_SURFACE_FOR_RETURN_ANIMATION) != 0) {

            if (!mCanStartTasksFromRecents) {

                throw new SecurityException("Requires START_TASKS_FROM_RECENTS permission");
@@ -365,9 +361,6 @@ class Session extends IWindowSession.Stub implements IBinder.DeathRecipient { 
    @VisibleForTesting

    void validateAndResolveDragMimeTypeExtras(ClipData data, int callingUid, int callingPid,

            String callingPackage) {

        if (callingUid == Process.SYSTEM_UID) {

            throw new IllegalStateException("Need to validate before calling identify is cleared");

        }

        final ClipDescription desc = data != null ? data.getDescription() : null;

        if (desc == null) {

            return;

services/tests/wmtests/src/com/android/server/wm/DragDropControllerTests.java

+2 −4
Original line number Diff line number Diff line
@@ -467,8 +467,7 @@ public class DragDropControllerTests extends WindowTestsBase { 
            public void onAnimatorScaleChanged(float scale) {}

        });

        try {

            session.validateDragFlags(View.DRAG_FLAG_REQUEST_SURFACE_FOR_RETURN_ANIMATION,

                    TEST_UID);

            session.validateDragFlags(View.DRAG_FLAG_REQUEST_SURFACE_FOR_RETURN_ANIMATION);

            fail("Expected failure without permission");

        } catch (SecurityException e) {

            // Expected failure
@@ -484,8 +483,7 @@ public class DragDropControllerTests extends WindowTestsBase { 
            public void onAnimatorScaleChanged(float scale) {}

        });

        try {

            session.validateDragFlags(View.DRAG_FLAG_REQUEST_SURFACE_FOR_RETURN_ANIMATION,

                    TEST_UID);

            session.validateDragFlags(View.DRAG_FLAG_REQUEST_SURFACE_FOR_RETURN_ANIMATION);

            // Expected pass

        } catch (SecurityException e) {

            fail("Expected no failure with permission");