commit de619fa28e85b224933b4ceaccf5f4a30138badc
author Garfield Tan <xutan@google.com> Fri Oct 02 17:13:53 2020 -0700
committer Garfield Tan <xutan@google.com> Thu Oct 08 12:23:51 2020 -0700
tree f2684b647cc567153615cc8af3ae56c0ed2efa6d
parent 693291a8dc22931e0c3432a04f0ab968630163cb

Make a layer secure if its parent is secure.

Dialogs and context menus can be captured in screenshots even if their
parent layer/window is marked secure. Therefore we should let the secure
flag be inherited from their parents as well.

Bug: 169851503
Test: Screen capture can't capture dialogs in a window marked secure.
Test: atest libsurfaceflinger_unittest
Test: atest SurfaceFlinger_test:ScreenCaptureTest
Change-Id: I0f32a03aeb733682df787105b051c691d1da7bc6

services/surfaceflinger/tests/ScreenCapture_test.cpp

diff --git a/services/surfaceflinger/tests/ScreenCapture_test.cpp b/services/surfaceflinger/tests/ScreenCapture_test.cpp
index e173996..7df3711 100644
--- a/services/surfaceflinger/tests/ScreenCapture_test.cpp
+++ b/services/surfaceflinger/tests/ScreenCapture_test.cpp
@@ -109,6 +109,41 @@
     sc.expectColor(Rect(0, 0, 32, 32), Color::RED);
 }
 
+TEST_F(ScreenCaptureTest, CaptureChildSetParentFlagsSecureEUidSystem) {
+    sp<SurfaceControl> parentLayer;
+    ASSERT_NO_FATAL_FAILURE(
+            parentLayer = createLayer("parent-test", 32, 32,
+                                      ISurfaceComposerClient::eSecure |
+                                              ISurfaceComposerClient::eFXSurfaceBufferQueue));
+    ASSERT_NO_FATAL_FAILURE(fillBufferQueueLayerColor(parentLayer, Color::RED, 32, 32));
+
+    sp<SurfaceControl> childLayer;
+    ASSERT_NO_FATAL_FAILURE(childLayer = createLayer("child-test", 10, 10,
+                                                     ISurfaceComposerClient::eFXSurfaceBufferQueue,
+                                                     parentLayer.get()));
+    ASSERT_NO_FATAL_FAILURE(fillBufferQueueLayerColor(childLayer, Color::BLUE, 10, 10));
+
+    Transaction().show(parentLayer).setLayer(parentLayer, INT32_MAX).show(childLayer).apply(true);
+
+    UIDFaker f(AID_SYSTEM);
+
+    {
+        SCOPED_TRACE("as system");
+        auto shot = screenshot();
+        shot->expectColor(Rect(0, 0, 10, 10), Color::BLACK);
+    }
+
+    // Here we pass captureSecureLayers = true and since we are AID_SYSTEM we should be able
+    // to receive them...we are expected to take care with the results.
+    DisplayCaptureArgs args;
+    args.displayToken = mDisplay;
+    args.captureSecureLayers = true;
+    ASSERT_EQ(NO_ERROR, ScreenCapture::captureDisplay(args, mCaptureResults));
+    ASSERT_TRUE(mCaptureResults.capturedSecureLayers);
+    ScreenCapture sc(mCaptureResults.buffer);
+    sc.expectColor(Rect(0, 0, 10, 10), Color::BLUE);
+}
+
 TEST_F(ScreenCaptureTest, CaptureSingleLayer) {
     LayerCaptureArgs captureArgs;
     captureArgs.layerHandle = mBGSurfaceControl->getHandle();
@@ -801,4 +836,4 @@
     verify([&] { screenshot()->expectChildColor(80, 80); });
 }
 
-} // namespace android
\ No newline at end of file
+} // namespace android