Introduction

UTopia is a tool for automatically generating fuzz drivers from unit tests.

UTopia will let developers perform fuzz testing without special knowledge about writing fuzzers. Even developers familiar with fuzzing can save significant time by generating fuzz drivers automatically.

UTopia supports C/C++ libraries which have unit tests with GoogleTest, Boost.Test or Tizen TCT.

Trophy

To see bugs found by UTopia, visit Trophy page. You can also see some UTopia-based fuzzers there.

Docker

For easy set up, we provide docker image for running UTopia. You can build UTopia and generate/run fuzzers inside docker container.

Build docker image with command below.

docker buildx build -f docker/Dockerfile -t utopia .

Build

UTopia depends on LLVM, Protobuf and GoogleTest. You can install dependencies manually, but we recommend to use given docker image.

To build UTopia, follow cmake process below.

cd $UTOPIA_HOME_DIR
cmake -B build -S .
cmake --build build -j$(nproc)

Run

For some selected projects, you can use helper script to run our tool without further effort. Please refer helper/README.md. For other projects, please check following manual.

target_analyzer

Target Analyzer analyzes target library code and generates a result as json file. Mandatory command line options are below.

target_analyzer --entry ${entry_path} --extern ${extern_path} --name ${lib_name} --public ${api_json_path} --out ${output_path}

entry_path

Entry is a json file to indicate paths of AST and IR files of target library code. Its format looks like below.

library.a.json

{
  "binary_info": {
    "libcommon.a": {
      "bc_file": "/root/fuzz-test-generation/exp/sample/output/bc/libcommon.a.bc"
    }
  },
  "project_dir": "/root/fuzz-test-generation/exp/sample",
  "project_name": "sample"
}

You should specify LLVM bitcode file path of a specific library using "bc_file" keyword. We only accept one bitcode file so far, thus you may use llvm-link to link several bit code files to one bit code file.

Note that, if entry_path is library.a.json, there should be compiles_library.a.json in the same directory has the same format. And its format is like below.

compiles_library.a.json

[
  {
    "ast_file": "/root/fuzz-test-generation/exp/sample/libcommon.a_ast/codec/common/src/ast1.o.ast"
  },
  {
    "ast_file": "/root/fuzz-test-generation/exp/sample/libcommon.a_ast/codec/common/src/ast2.o.ast"
  }
]

You should specify AST file path of a specific library using "ast_file" keyword and its array. Note that a specified bitcode file and ast files are generated from same source codes for a specific library.

extern_path

Target Analyzer accepts target analyzer report of other libraries for an accurate result. This path should be a directory path where other reports stored, which means more than one library reports are allowed.

lib_name

Library name to be analyzed. This name should be specified in "binary_info" of entry json file.

api_json_path

API function names to be analyzed. It should be json file formatted as below.

{
  "libcommon.a": [
    "API1",
    "API2",
    "API3"
  ]
}

You can get API list from a specific library using command below.

nm --no-demangle --defined-only -g ${librarypath} | awk '$2=="T" {k=""; for(i=3;i<=NF;i++) k=k $i""; print k}'

ut_analyzer

UT Analyzer analyzes unit test code for a target library and generates a result as json file. Mandatory command line options are below.

ut_analyzer --entry ${entry_path} --extern ${extern_path} --name ${lib_name} --public ${api_json_path} --out ${output_path}

All options are same as the target_analyzer. Note that, entry_path should specify AST/IR files for a unit test executable, not library.

fuzz_generator

fuzz_generator generates fuzz drivers using report files of target_anlayzer and ut_analyzer. Mandatory command line options are below.

fuzz_generator --src ${src_path} --target ${target_analyzer_report_path} --ut ${ut_analyzer_report_path} --public ${api_json_path} --out ${output_dir}

src_path

src_path is the directory path where unit test source code is stored. fuzz_generator copy this directory and generates fuzz driver by modifying these copied files.

Other options are same as the target_analyzer options.

Build generated fuzz drivers

Fuzz drivers are generated in ${output_dir} passed to fuzz_generator as command line option. You can build them using same compiler command for unit test executable. Note that, you should include fuzz_entry.cc, FuzzArgsProto.pb.cc files that are generated by fuzz_generator. You can find those files in ${output_dir}.