High level conclusions

Reachability and coverage overview

The following table shows data about each function in the project. The functions included in this table correspond to all functions that exist in the executables of the fuzzers. As such, there may be functions that are from third-party libraries.

Fuzzer: cpython/Modules/_xxtestfuzz/fuzzer.c

Call tree

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Runtime coverage analysis

Files reached

Optimal target analysis

Remaining optimal interesting functions

The following table shows a list of functions that are optimal targets. Optimal targets are identified by finding the functions that in combination, yield a high code coverage.

Implementing fuzzers that target the above functions will improve reachability such that it becomes:

All functions overview

If you implement fuzzers for these functions, the status of all functions in the project will be:

This sections provides heuristics that can be used as input to a fuzz engine when running a given fuzz target. The current focus is on providing input that is usable by libFuzzer.

cpython/Modules/_xxtestfuzz/fuzzer.c

Dictionary

Use this with the libFuzzer -dict=DICT.file flag

Fuzzer function priority

Use one of these functions as input to libfuzzer with flag: -focus_function name

-focus_function=['_PyPegen_run_parser', 'PyEval_SaveThread', 'eval_rule', '_Py_freelists_GET', 'convertsimple', '_PyUnicodeWriter_InitWithBuffer', 'PyUnicode_DecodeFSDefaultAndSize', 'tstate_deactivate', 'file_rule', '_PyToken_Free']

This section shows analysis of runtime coverage data.

Complex functions with low coverage

New fuzzers

The below fuzzers are templates and suggestions for how to target the set of optimal functions above

main.c

#include "ada_fuzz_header.h"

int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
  af_safe_gb_init(data, size);

  /* target pymain_main */
  UNKNOWN_TYPE unknown_0;
  pymain_main(unknown_0);

  af_safe_gb_cleanup();
}

Files in report