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
Test: TBD

Change-Id: Id92ccb087bd0d8dbaeeef3ba50b67fe015e53db8

4 files changed, 28 insertions, 0 deletions

diff --git a/libs/gui/LayerState.cpp b/libs/gui/LayerState.cpp
index 2d99fc1903..076c90dd23 100644
--- a/libs/gui/LayerState.cpp
+++ b/libs/gui/LayerState.cpp
@@ -64,6 +64,7 @@ layer_state_t::layer_state_t()
         fixedTransformHint(ui::Transform::ROT_INVALID),
         frameNumber(0),
         autoRefresh(false),
+        isTrustedOverlay(false),
         bufferCrop(Rect::INVALID_RECT),
         destinationFrame(Rect::INVALID_RECT),
         releaseBufferListener(nullptr) {
@@ -170,6 +171,7 @@ status_t layer_state_t::write(Parcel& output) const
     SAFE_PARCEL(output.write, stretchEffect);
     SAFE_PARCEL(output.write, bufferCrop);
     SAFE_PARCEL(output.write, destinationFrame);
+    SAFE_PARCEL(output.writeBool, isTrustedOverlay);
 
     return NO_ERROR;
 }
@@ -300,6 +302,7 @@ status_t layer_state_t::read(const Parcel& input)
     SAFE_PARCEL(input.read, stretchEffect);
     SAFE_PARCEL(input.read, bufferCrop);
     SAFE_PARCEL(input.read, destinationFrame);
+    SAFE_PARCEL(input.readBool, &isTrustedOverlay);
 
     return NO_ERROR;
 }
@@ -532,6 +535,10 @@ void layer_state_t::merge(const layer_state_t& other) {
         what |= eAutoRefreshChanged;
         autoRefresh = other.autoRefresh;
     }
+    if (other.what & eTrustedOverlayChanged) {
+        what |= eTrustedOverlayChanged;
+        isTrustedOverlay = other.isTrustedOverlay;
+    }
     if (other.what & eReleaseBufferListenerChanged) {
         if (releaseBufferListener) {
             ALOGW("Overriding releaseBufferListener");
diff --git a/libs/gui/SurfaceComposerClient.cpp b/libs/gui/SurfaceComposerClient.cpp
index 6ea070ea2f..96da8efd19 100644
--- a/libs/gui/SurfaceComposerClient.cpp
+++ b/libs/gui/SurfaceComposerClient.cpp
@@ -1656,6 +1656,19 @@ SurfaceComposerClient::Transaction& SurfaceComposerClient::Transaction::setAutoR
     return *this;
 }
 
+SurfaceComposerClient::Transaction& SurfaceComposerClient::Transaction::setTrustedOverlay(
+        const sp<SurfaceControl>& sc, bool isTrustedOverlay) {
+    layer_state_t* s = getLayerState(sc);
+    if (!s) {
+        mStatus = BAD_INDEX;
+        return *this;
+    }
+
+    s->what |= layer_state_t::eTrustedOverlayChanged;
+    s->isTrustedOverlay = isTrustedOverlay;
+    return *this;
+}
+
 SurfaceComposerClient::Transaction& SurfaceComposerClient::Transaction::setApplyToken(
         const sp<IBinder>& applyToken) {
     mApplyToken = applyToken;
diff --git a/libs/gui/include/gui/LayerState.h b/libs/gui/include/gui/LayerState.h
index 465e34ca33..3e57ff611e 100644
--- a/libs/gui/include/gui/LayerState.h
+++ b/libs/gui/include/gui/LayerState.h
@@ -118,6 +118,7 @@ struct layer_state_t {
         eBlurRegionsChanged = 0x800'00000000,
         eAutoRefreshChanged = 0x1000'00000000,
         eStretchChanged = 0x2000'00000000,
+        eTrustedOverlayChanged = 0x4000'00000000,
     };
 
     layer_state_t();
@@ -225,6 +226,10 @@ struct layer_state_t {
     // in shared buffer mode.
     bool autoRefresh;
 
+    // An inherited state that indicates that this surface control and its children
+    // should be trusted for input occlusion detection purposes
+    bool isTrustedOverlay;
+
     // Stretch effect to be applied to this layer
     StretchEffect stretchEffect;
 
diff --git a/libs/gui/include/gui/SurfaceComposerClient.h b/libs/gui/include/gui/SurfaceComposerClient.h
index c2963b58df..baa0567617 100644
--- a/libs/gui/include/gui/SurfaceComposerClient.h
+++ b/libs/gui/include/gui/SurfaceComposerClient.h
@@ -537,6 +537,9 @@ public:
         // in shared buffer mode.
         Transaction& setAutoRefresh(const sp<SurfaceControl>& sc, bool autoRefresh);
 
+        // Sets that this surface control and its children are trusted overlays for input
+        Transaction& setTrustedOverlay(const sp<SurfaceControl>& sc, bool isTrustedOverlay);
+
         // Queues up transactions using this token in SurfaceFlinger.  By default, all transactions
         // from a client are placed on the same queue. This can be used to prevent multiple
         // transactions from blocking each other.