android13/frameworks/av/media/libaaudio/fuzzer

Fuzzer for libaaudio

Plugin Design Considerations

The fuzzer plugin for libaaudio are designed based on the understanding of the source code 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.

Fuzzers assigns values to the following parameters to pass on to libaaudio:

1. Device Id (parameter name: deviceId)
2. Sampling Rate (parameter name: sampleRate)
3. Number of channels (parameter name: channelCount)
4. Audio Travel Direction (parameter name: direction)
5. Audio Format (parameter name: format)
6. Audio Sharing Mode (parameter name: sharingMode)
7. Audio Usage (parameter name: usage)
8. Audio Content type (parameter name: contentType)
9. Audio Input Preset (parameter name: inputPreset)
10. Audio Privacy Sensitivity (parameter name: privacySensitive)
11. Buffer Capacity In Frames (parameter name: frames)
12. Performance Mode (parameter name: mode)
13. Allowed Capture Policy (parameter name: allowedCapturePolicy)
14. Session Id (parameter name: sessionId)
15. Frames per Data Callback (parameter name: framesPerDataCallback)
16. MMap Policy (parameter name: policy)

Parameter	Valid Values	Configured Value
deviceId	Any value of type int32_t	Value obtained from FuzzedDataProvider
sampleRate	Any value of type int32_t	Value obtained from FuzzedDataProvider
channelCount	Any value of type int32_t	Value obtained from FuzzedDataProvider
direction	0. AAUDIO_DIRECTION_OUTPUT 1. AAUDIO_DIRECTION_INPUT	Value obtained from FuzzedDataProvider
format	0. AAUDIO_FORMAT_INVALID 1. AAUDIO_FORMAT_UNSPECIFIED 2. AAUDIO_FORMAT_PCM_I16 3. AAUDIO_FORMAT_PCM_FLOAT	Value obtained from FuzzedDataProvider
sharingMode	0. AAUDIO_SHARING_MODE_EXCLUSIVE 1. AAUDIO_SHARING_MODE_SHARED	Value obtained from FuzzedDataProvider
usage	0. AAUDIO_USAGE_MEDIA 1. AAUDIO_USAGE_VOICE_COMMUNICATION 2. AAUDIO_USAGE_VOICE_COMMUNICATION_SIGNALLING 3. AAUDIO_USAGE_ALARM 4. AAUDIO_USAGE_NOTIFICATION 5. AAUDIO_USAGE_NOTIFICATION_RINGTONE 6. AAUDIO_USAGE_NOTIFICATION_EVENT 7. AAUDIO_USAGE_ASSISTANCE_ACCESSIBILITY 8. AAUDIO_USAGE_ASSISTANCE_NAVIGATION_GUIDANCE 9. AAUDIO_USAGE_ASSISTANCE_SONIFICATION 10. AAUDIO_USAGE_GAME 11. AAUDIO_USAGE_ASSISTANT 12. AAUDIO_SYSTEM_USAGE_EMERGENCY 13. AAUDIO_SYSTEM_USAGE_SAFETY 14. AAUDIO_SYSTEM_USAGE_VEHICLE_STATUS 15. AAUDIO_SYSTEM_USAGE_ANNOUNCEMENT	Value obtained from FuzzedDataProvider
contentType	0. AAUDIO_CONTENT_TYPE_SPEECH 1. AAUDIO_CONTENT_TYPE_MUSIC 2. AAUDIO_CONTENT_TYPE_MOVIE 3. AAUDIO_CONTENT_TYPE_SONIFICATION	Value obtained from FuzzedDataProvider
inputPreset	0. AAUDIO_INPUT_PRESET_GENERIC 1. AAUDIO_INPUT_PRESET_CAMCORDER 2. AAUDIO_INPUT_PRESET_VOICE_RECOGNITION 3. AAUDIO_INPUT_PRESET_VOICE_COMMUNICATION 4. AAUDIO_INPUT_PRESET_UNPROCESSED 5. AAUDIO_INPUT_PRESET_VOICE_PERFORMANCE	Value obtained from FuzzedDataProvider
privacySensitive	0. true 1. false	Value obtained from FuzzedDataProvider
frames	Any value of type int32_t	Value obtained from FuzzedDataProvider
mode	0. AAUDIO_PERFORMANCE_MODE_NONE 1. AAUDIO_PERFORMANCE_MODE_POWER_SAVING 2. AAUDIO_PERFORMANCE_MODE_LOW_LATENCY	Value obtained from FuzzedDataProvider
allowedCapturePolicy	0. AAUDIO_ALLOW_CAPTURE_BY_ALL 1. AAUDIO_ALLOW_CAPTURE_BY_SYSTEM 2. AAUDIO_ALLOW_CAPTURE_BY_NONE	Value obtained from FuzzedDataProvider
sessionId	0. AAUDIO_SESSION_ID_NONE 1. AAUDIO_SESSION_ID_ALLOCATE	Value obtained from FuzzedDataProvider
framesPerDataCallback	Any value of type int32_t	Value obtained from FuzzedDataProvider
policy	0. AAUDIO_POLICY_NEVER 1. AAUDIO_POLICY_AUTO 2. AAUDIO_POLICY_ALWAYS	Value obtained from FuzzedDataProvider

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

Maximize utilization of input data

The plugin feed the entire input data to the module. This ensures that the plugins tolerates any kind of input (empty, huge, malformed, etc) and doesn't exit() on any input and thereby increasing the chance of identifying vulnerabilities.

Build

This describes steps to build libaaudio_fuzzer binary.

Android

Steps to build

Build the fuzzer

  $ mm -j$(nproc) libaaudio_fuzzer

Steps to run

To run on device

  $ adb sync data
  $ adb shell /data/fuzz/arm64/libaaudio_fuzzer/libaaudio_fuzzer

References:

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