Mitigate the security vulnerability by sanitizing the transaction flags. am: 3ea58dbc1d am: 8b172cefcb

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/native/+/20886664

Change-Id: I3831739ed5fe30094f64400fc38e9c8a18cf7807
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

2 files changed, 22 insertions, 0 deletions

diff --git a/libs/gui/LayerState.cpp b/libs/gui/LayerState.cpp
index bf275a5900..9654a60310 100644
--- a/libs/gui/LayerState.cpp
+++ b/libs/gui/LayerState.cpp
@@ -391,6 +391,27 @@ void DisplayState::merge(const DisplayState& other) {
     }
 }
 
+void DisplayState::sanitize(int32_t permissions) {
+    if (what & DisplayState::eLayerStackChanged) {
+        if (!(permissions & layer_state_t::Permission::ACCESS_SURFACE_FLINGER)) {
+            what &= ~DisplayState::eLayerStackChanged;
+            ALOGE("Stripped attempt to set eLayerStackChanged in sanitize");
+        }
+    }
+    if (what & DisplayState::eDisplayProjectionChanged) {
+        if (!(permissions & layer_state_t::Permission::ACCESS_SURFACE_FLINGER)) {
+            what &= ~DisplayState::eDisplayProjectionChanged;
+            ALOGE("Stripped attempt to set eDisplayProjectionChanged in sanitize");
+        }
+    }
+    if (what & DisplayState::eSurfaceChanged) {
+        if (!(permissions & layer_state_t::Permission::ACCESS_SURFACE_FLINGER)) {
+            what &= ~DisplayState::eSurfaceChanged;
+            ALOGE("Stripped attempt to set eSurfaceChanged in sanitize");
+        }
+    }
+}
+
 void layer_state_t::sanitize(int32_t permissions) {
     // TODO: b/109894387
     //
diff --git a/libs/gui/include/gui/LayerState.h b/libs/gui/include/gui/LayerState.h
index 2a8d30d2da..e5a029b1ff 100644
--- a/libs/gui/include/gui/LayerState.h
+++ b/libs/gui/include/gui/LayerState.h
@@ -278,6 +278,7 @@ struct DisplayState {
 
     DisplayState();
     void merge(const DisplayState& other);
+    void sanitize(int32_t permissions);
 
     uint32_t what;
     sp<IBinder> token;