Fuzzer for libcameraservice

Plugin Design Considerations

The fuzzer plugin 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.

libcameraservice supports the following parameters:

1. Camera Type (parameter name: cameraType)
2. Camera API Version (parameter name: cameraAPIVersion)
3. Event ID (parameter name: eventId)
4. Camera Sound Kind (parameter name: soundKind)
5. Shell Command (parameter name: shellCommand)

Parameter	Valid Values	Configured Value
cameraType	0. CAMERA_TYPE_BACKWARD_COMPATIBLE 1. CAMERA_TYPE_ALL	Value obtained from FuzzedDataProvider
cameraAPIVersion	0. API_VERSION_1 1. API_VERSION_2	Value obtained from FuzzedDataProvider
eventId	0. EVENT_USER_SWITCHED 1. EVENT_NONE	Value obtained from FuzzedDataProvider
soundKind	0. SOUND_SHUTTER 1. SOUND_RECORDING_START 2. SOUND_RECORDING_STOP	Value obtained from FuzzedDataProvider
shellCommand	0. set-uid-state 1. reset-uid-state 2. get-uid-state 3. set-rotate-and-crop 4. get-rotate-and-crop 5. help	Value obtained from FuzzedDataProvider

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

Maximize utilization of input data

The plugin 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 camera_service_fuzzer binary.

Android

Steps to build

Build the fuzzer

  $ mm -j$(nproc) camera_service_fuzzer

Steps to run

Create a directory CORPUS_DIR

  $ adb shell mkdir CORPUS_DIR

To run on device

  $ adb sync data
  $ adb shell /data/fuzz/arm64/camera_service_fuzzer/camera_service_fuzzer CORPUS_DIR

References:

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