Android/frameworks_base
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Document go/untrusted-touches

Browse Source 
The only public API (that I know!) that let touches pass-through is
FLAG_NOT_TOUCHABLE, so I've put the rules that relate to app-developers
there.

Please let me know if there are any other public APIs that makes a
window let touches pass-through. The other one I know of is
ViewTreeObserver.addOnComputeInternalInsetsListener() that let's you
specify the touchableRegion, but that's not public.

(The feature works regardless of the API used to make the window
pass-through)

The docs are a shorter version of the "Rules" section of
go/untrusted-touches.

Bug: 158002302
Fix: 173022596
Test: Build
Change-Id: Ic7ba68f03587112db2cc93128ac41cb09d443127
This commit is contained in:
Bernardo Rufino
2021-01-11 16:16:08 +00:00
parent 8dd46b0ef1
commit e5215b4853
2 changed files with 48 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
core/java/android/hardware/input/InputManager.java
View File

@@ -201,8 +201,6 @@ public final class InputManager {
* Prevent touches from being consumed by apps if these touches passed through a non-trusted
* window from a different UID and are considered unsafe.
*
* TODO(b/158002302): Turn the feature on by default
*
* @hide
*/
@TestApi

49
core/java/android/view/WindowManager.java
View File

@@ -1518,7 +1518,54 @@ public interface WindowManager extends ViewManager {
* can use {@link #FLAG_ALT_FOCUSABLE_IM} to modify this behavior. */
public static final int FLAG_NOT_FOCUSABLE = 0x00000008;
/** Window flag: this window can never receive touch events. */
/**
* Window flag: this window can never receive touch events.
*
* <p>The intention of this flag is to leave the touch to be handled by some window below
* this window (in Z order).
*
* <p>Starting from Android {@link Build.VERSION_CODES#S}, for security reasons, touch
* events that pass through windows containing this flag (ie. are within the bounds of the
* window) will only be delivered to the touch-consuming window if one (or more) of the
* items below are true:
* <ol>
* <li><b>Same UID</b>: This window belongs to the same UID that owns the touch-consuming
* window.
* <li><b>Trusted windows</b>: This window is trusted. Trusted windows include (but are
* not limited to) accessibility windows ({@link #TYPE_ACCESSIBILITY_OVERLAY}), the IME
* ({@link #TYPE_INPUT_METHOD}) and assistant windows (TYPE_VOICE_INTERACTION). Windows of
* type {@link #TYPE_APPLICATION_OVERLAY} are <b>not</b> trusted, see below.
* <li><b>Invisible windows</b>: This window is {@link View#GONE} or
* {@link View#INVISIBLE}.
* <li><b>Fully transparent windows</b>: This window has {@link LayoutParams#alpha} equal
* to 0.
* <li><b>One SAW window with enough transparency</b>: This window is of type {@link
* #TYPE_APPLICATION_OVERLAY}, has {@link LayoutParams#alpha} below or equal to <b>0.8</b>
* and it's the <b>only</b> window of type {@link #TYPE_APPLICATION_OVERLAY} from this UID
* in the touch path.
* <li><b>Multiple SAW windows with enough transparency</b>: The multiple overlapping
* {@link #TYPE_APPLICATION_OVERLAY} windows in the
* touch path from this UID have a <b>combined obscuring opacity</b> below or equal to
* <b>0.8</b>. See section below on how to compute this value.
* </ol>
* <p>If none of these cases hold, the touch will not be delivered and a message will be
* logged to logcat.</p>
*
* <a name="ObscuringOpacity"></a>
* <h3>Combined obscuring opacity</h3>
*
* <p>The <b>combined obscuring opacity</b> of a set of windows is obtained by combining the
* opacity values of all windows in the set using the associative and commutative operation
* defined as:
* <pre>
* opacity({A,B}) = 1 - (1 - opacity(A))*(1 - opacity(B))
* </pre>
* <p>where {@code opacity(X)} is the {@link LayoutParams#alpha} of window X. So, for a set
* of windows {@code {W1, .., Wn}}, the combined obscuring opacity will be:
* <pre>
* opacity({W1, .., Wn}) = 1 - (1 - opacity(W1)) * ... * (1 - opacity(Wn))
* </pre>
*/
public static final int FLAG_NOT_TOUCHABLE = 0x00000010;
/** Window flag: even when this window is focusable (its