July 29, 2020
In late May 2020, we were asked to help triage the root cause of a bug where an image, when parsed by Android SystemUI, caused the Android process to crash. This could cause a boot loop if, for example, the image was set as the phone’s background. We quickly identified the root cause which we found interesting from an ecosystem perspective.
This blog shares parts of our analysis, and covers our trace of the relevant code path and diagnosis of the root cause. We describe how the fixes work, and then dive into why this bug was only seen relatively recently. Finally, we break down the file’s JPEG and ICC structures, and what impacts these may have on the parsers.