Fuzzer for libmedia_codecserviceregistrant

Plugin Design Considerations

The fuzzer plugin for libmedia_codecserviceregistrant is designed based on the understanding of the library and tries to achieve the following:

Maximize code coverage

The configuration parameters are not hardcoded, but instead selected based on incoming data. This ensures more code paths are reached by the fuzzer.

libmedia_codecserviceregistrant supports the following parameters:

1. C2String (parameter name: c2String)
2. Width (parameter name: width)
3. Height (parameter name: height)
4. SamplingRate (parameter name: samplingRate)
5. Channels (parameter name: channels)
6. Stream (parameter name: stream)

Parameter	Valid Values	Configured Value
c2String	String	Value obtained from FuzzedDataProvider
width	UINT32_MIN to UINT32_MAX	Value obtained from FuzzedDataProvider
height	UINT32_MIN to UINT32_MAX	Value obtained from FuzzedDataProvider
samplingRate	UINT32_MIN to UINT32_MAX	Value obtained from FuzzedDataProvider
channels	UINT32_MIN to UINT32_MAX	Value obtained from FuzzedDataProvider
stream	UINT32_MIN to UINT32_MAX	Value obtained from FuzzedDataProvider

This also ensures that the plugin is always deterministic for any given input.

Maximize utilization of input data

The plugin feeds the entire input data to the libmedia_codecserviceregistrant module. This ensures that the plugin tolerates any kind of input (empty, huge, malformed, etc) and doesnt exit() on any input and thereby increasing the chance of identifying vulnerabilities.

Build

This describes steps to build codecServiceRegistrant_fuzzer binary.

Android

Steps to build

Build the fuzzer

  $ mm -j$(nproc) codecServiceRegistrant_fuzzer

Steps to run

To run on device

  $ adb sync data
  $ adb shell /data/fuzz/${TARGET_ARCH}/codecServiceRegistrant_fuzzer/codecServiceRegistrant_fuzzer

References:

• http://llvm.org/docs/LibFuzzer.html
• https://github.com/google/oss-fuzz