Orangfuzz – an experimental user interaction fuzzer for Firefox OS

One of the goals of the fuzzing team is to identify security vulnerabilities within our products using various techniques. As we continue working with Firefox OS, we need to build and adapt the proper tools to enable fuzz testing on the mobile device.

Orangfuzz is an experimental user interaction fuzzer. It builds on generate-orangutan-script.py and uses the Orangutan framework. Orangutan injects events directly into the low-level kernel device file that represents an Android device‚Äôs touch screen. It supports actions such as “tapping” and “dragging”, simulated from a user’s perspective. The fuzzer generates an Orangutan script containing random sets of these actions.

This concept was inspired by bug 838215, which was a crash involving the handling of touch events.

Orangfuzz currently only supports the B2G Test Driver device, but adding additional support for other devices, if Orangutan supports them, is straightforward. We define the device through its specifications (e.g. home key location, screen resolution). Adding support for additional devices is as simple as adding new subclasses which provide the appropriate resolution and screensizes. It may be possible to run this against the B2G emulators but this has not been tested.

Warning: It is entirely possible to generate a script that contains a set of actions that dial emergency numbers such as “911”, “112” or “999”, so it is recommended to run the script against a special build of Gaia (not yet well-tested) with dialing and messaging capabilities disabled if one wants to run orangfuzz continuously without supervision.

How can you help?

At this point we are still experimenting with the most effective strategy for identifying and triaging crashes, but please feel free to file bugs or ideas moving forward either on GitHub or in Bugzilla. Do subscribe to the mozilla.dev.b2g newsgroup if one is interested.

Bug 858174 tracks moving orangfuzz to production.

A demonstration video on YouTube with annotations is available, or you can get the .webm version (no audio).

-Gary Kwong

* Credits go out to Gregor Wagner, who wrote generate-orangutan-script.py, and William Lachance, author of the Orangutan framework.