Block untrusted touches in InputDispatcher
With topic CL InputDispatcher now has the effect of each window for
cross-UID touch occlusion rules: ALLOW, USE_OPACITY or BLOCK_UNTRUSTED.
Check topic CL for exact meaning of each. USE_OPACITY is only used by
SAWs for now.
In this CL, InputDispatcher make use of that information for the stack
of windows above the touch-consuming window to block a touch or not.
The summary of the rules are:
* If there is any visible untrusted window from a different UID (than
the touch-consuming window UID) that has state BLOCK_UNTRUSTED, the
touch is blocked.
* Else, if there is any visible untrusted window from a different UID
that has state USE_OPACITY, we compute the composed obscuring opacity
by each stack of USE_OPACITY windows per UID of occluding window.
We take maximum of those and compare with secure setting
"maximum_obscuring_opacity_for_touch", if it's greater than the
setting the touch is blocked. This means the remaining visibility on the
touch-consuming window is not high enough to let the touch happen.
* Else we don't block the touch.
More details on go/cross-uid-touches. This doesn't interfere with
existing flags FLAG_WINDOW_IS_OBSCURED and
FLAG_WINDOW_IS_PARTIALLY_OBSCURED.
To compute the opacity we also propagate the alpha of each window from
SurfaceFlinger to InputDispatcher.
Test: atest WindowUntrustedTouchTest
Test: atest inputflinger_tests inputflinger_benchmarks libinput_tests
Test: go/try-cross-uid-touches for manual testing
Bug: 158002302
Change-Id: I673d7a5f16b19952311e8cb44a48af4349a4bd40
diff --git a/services/inputflinger/dispatcher/include/InputDispatcherInterface.h b/services/inputflinger/dispatcher/include/InputDispatcherInterface.h
index 67d9a06..65687c4 100644
--- a/services/inputflinger/dispatcher/include/InputDispatcherInterface.h
+++ b/services/inputflinger/dispatcher/include/InputDispatcherInterface.h
@@ -20,12 +20,15 @@
#include <InputListener.h>
#include <android-base/result.h>
#include <android/FocusRequest.h>
+#include <android/os/BlockUntrustedTouchesMode.h>
#include <android/os/ISetInputWindowsListener.h>
#include <input/InputApplication.h>
#include <input/InputTransport.h>
#include <input/InputWindow.h>
#include <unordered_map>
+using android::os::BlockUntrustedTouchesMode;
+
namespace android {
/*
@@ -145,6 +148,21 @@
*/
virtual void setInTouchMode(bool inTouchMode) = 0;
+ /**
+ * Sets the maximum allowed obscuring opacity by UID to propagate touches.
+ * For certain window types (eg. SAWs), the decision of honoring
+ * FLAG_NOT_TOUCHABLE or not depends on the combined obscuring opacity of
+ * the windows above the touch-consuming window.
+ */
+ virtual void setMaximumObscuringOpacityForTouch(float opacity) = 0;
+
+ /**
+ * Sets the mode of the block untrusted touches feature.
+ *
+ * TODO(b/169067926): Clean-up feature modes.
+ */
+ virtual void setBlockUntrustedTouchesMode(BlockUntrustedTouchesMode mode) = 0;
+
/* Transfers touch focus from one window to another window.
*
* Returns true on success. False if the window did not actually have touch focus.