Clear the Parcel before writing an exception during a transaction

This prevents any object data from being accidentally overwritten by the
exception, which could cause unexpected malformed objects to be sent
across the transaction.

Test: atest CtsOsTestCases:ParcelTest#testExceptionOverwritesObject
Fixes: 34175893
Change-Id: Iaf80a0ad711762992b8ae60f76d861c97a403013
diff --git a/core/java/android/os/ b/core/java/android/os/
index 66ddf21..6178b2b 100644
--- a/core/java/android/os/
+++ b/core/java/android/os/
@@ -1033,6 +1033,8 @@
                     Log.w(TAG, "Caught a RuntimeException from the binder stub implementation.", e);
             } else {
+                // Clear the parcel before writing the exception
+                reply.setDataSize(0);