The fuzzer plugin for libbtdevice is designed based on the understanding of the source code and tries to achieve the following:
The configuration parameters are not hard-coded, but instead selected based on incoming data. This ensures more code paths are reached by the fuzzers.
Fuzzer assigns values to the following parameters to pass on to libbtdevice:
interopFeature)escoCodec)| Parameter | Valid Values | Configured Value |
|---|---|---|
interopFeature | 0.INTEROP_DISABLE_LE_SECURE_CONNECTIONS 1.INTEROP_AUTO_RETRY_PAIRING 2.INTEROP_DISABLE_ABSOLUTE_VOLUME 3.INTEROP_DISABLE_AUTO_PAIRING 4.INTEROP_KEYBOARD_REQUIRES_FIXED_PIN 5.INTEROP_2MBPS_LINK_ONLY 6.INTEROP_HID_PREF_CONN_SUP_TIMEOUT_3S 7.INTEROP_GATTC_NO_SERVICE_CHANGED_IND 8.INTEROP_DISABLE_AVDTP_RECONFIGURE 9.INTEROP_DYNAMIC_ROLE_SWITCH 10.INTEROP_DISABLE_ROLE_SWITCH 11.INTEROP_HID_HOST_LIMIT_SNIFF_INTERVAL 12.INTEROP_DISABLE_NAME_REQUEST 13.INTEROP_AVRCP_1_4_ONLY 14.INTEROP_DISABLE_SNIFF 15.INTEROP_DISABLE_AVDTP_SUSPEND | Value obtained from FuzzedDataProvider |
escoCodec | 0.SCO_CODEC_CVSD_D1 1.ESCO_CODEC_CVSD_S3 2.ESCO_CODEC_CVSD_S4 3.ESCO_CODEC_MSBC_T1 4.ESCO_CODEC_MSBC_T2 | Value obtained from FuzzedDataProvider |
| This also ensures that the plugins are always deterministic for any given input. |
The plugin feed the entire input data to the module. This ensures that 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.
This describes steps to build btdevice_esco_fuzzer binary.
Build the fuzzer
$ mm -j$(nproc) btdevice_esco_fuzzer
To run on device
$ adb sync data $ adb shell /data/fuzz/arm64/btdevice_esco_fuzzer/btdevice_esco_fuzzer