Fix potential decrypt src pointer overflow. am: c9b5693c7f am: 425466627b am: e0db28bc6c am: 68e65826c0

Original change: https://googleplex-android-review.googlesource.com/c/platform/hardware/interfaces/+/13412307

Change-Id: Ia748c2c17d7fa26fa238d6839f244998207acb6b