platform_system_core/fastboot/fuzzer/README.md

Fuzzer for libfastboot

Plugin Design Considerations

The fuzzer plugin for libfastboot is 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.

libfastboot supports the following parameters:

1. Year (parameter name: year)
2. Month (parameter name: month)
3. Day (parameter name: day)
4. Version (parameter name: version)
5. Fs Option (parameter name: fsOption)

Parameter	Valid Values	Configured Value
year	2000 to 2127	Value obtained from FuzzedDataProvider
month	1 to 12	Value obtained from FuzzedDataProvider
day	1 to 31	Value obtained from FuzzedDataProvider
version	0 to 127	Value obtained from FuzzedDataProvider
fsOption	0. casefold 1. projid 2. compress	Value obtained from FuzzedDataProvider

Maximize utilization of input data

The plugin feeds the entire input data to the 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 fastboot_fuzzer binary.

Android

Steps to build

Build the fuzzer

  $ mm -j$(nproc) fastboot_fuzzer_fuzzer

Steps to run

To run on host

  $ $ANDROID_HOST_OUT/fuzz/${TARGET_ARCH}/fastboot_fuzzer/fastboot_fuzzer CORPUS_DIR

References:

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