Add mechanism for a task's windows to be trusted overlays (SF)

- Add a layer state to indicate that this layer and its children
  in the hierarchy are trusted. This can only be set by callers
  holding ACCESS_SURFACE_FLINGER, and will be used for the PIP
  task layer to indicate that activities in PIP are trusted (as
  they are controlled only by the user and SystemUI)

Bug: 191529039
Bug: 196389741
Test: TBD

Change-Id: Id92ccb087bd0d8dbaeeef3ba50b67fe015e53db8
Merged-In: Id92ccb087bd0d8dbaeeef3ba50b67fe015e53db8

1 files changed, 9 insertions, 0 deletions

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 4a60d5c6f2..4947210929 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -3858,6 +3858,15 @@ uint32_t SurfaceFlinger::setClientStateLocked(
             flags |= eTraversalNeeded | eTransformHintUpdateNeeded;
         }
     }
+    if (what & layer_state_t::eTrustedOverlayChanged) {
+        if (privileged) {
+            if (layer->setTrustedOverlay(s.isTrustedOverlay)) {
+                flags |= eTraversalNeeded;
+            }
+        } else {
+            ALOGE("Attempt to set trusted overlay without permission ACCESS_SURFACE_FLINGER");
+        }
+    }
     // This has to happen after we reparent children because when we reparent to null we remove
     // child layers from current state and remove its relative z. If the children are reparented in
     // the same transaction, then we have to make sure we reparent the children first so we do not