No fuzzer binaries found

I created a job and uploaded my zip, however it’s complaining with:

2019-02-08 13:51:08,359 - run_bot - INFO - Checking for bad build.
2019-02-08 13:51:08,654 - run_bot - ERROR - Error occurred while working on task.
Traceback (most recent call last):
  File "src/python/bot/startup/run_bot.py", line 98, in task_loop
    commands.process_command(task)
  File "/home/vadi/Programs/Mudlet/mudlet1/clusterfuzz/src/python/bot/tasks/commands.py", line 147, in wrapper
    return func(task)
  File "/home/vadi/Programs/Mudlet/mudlet1/clusterfuzz/src/python/bot/tasks/commands.py", line 360, in process_command
    run_command(task_name, task_argument, job_name)
  File "/home/vadi/Programs/Mudlet/mudlet1/clusterfuzz/src/python/bot/tasks/commands.py", line 190, in run_command
    task_module.execute_task(task_argument, job_name)
  File "/home/vadi/Programs/Mudlet/mudlet1/clusterfuzz/src/python/bot/tasks/fuzz_task.py", line 1342, in execute_task
    data_directory, testcase_count)
  File "/home/vadi/Programs/Mudlet/mudlet1/clusterfuzz/src/python/bot/tasks/fuzz_task.py", line 742, in run_fuzzer
    testcase_count)
  File "/home/vadi/Programs/Mudlet/mudlet1/clusterfuzz/src/python/bot/fuzzers/builtin.py", line 72, in run
    'No fuzzer binaries found in |BUILD_DIR| directory.')
BuiltinFuzzerException: No fuzzer binaries found in |BUILD_DIR| directory.

What exactly is it talking about?

[jonathanmetzman]

To clarify since I think this issue has caused some confusion, for a binary to be recognized as a fuzzer it should have a function called LLVMFuzzerTestOneInput. The logic for determining if a binary is a fuzzer is here.

The libFuzzer target someone gives to ClusterFuzz doesn’t necessarily need to be compiled with -fsanitize=fuzzer but it should be a working libFuzzer target. -fsanitize=fuzzer-no-link does not do this, -fsanitize=fuzzer can do this but it is not the only way.

[jonathanmetzman]

With -fsanitize=address,fuzzer-no-link specifically (it complained about main() already defined).

Ah this is the issue. The program you give to ClusterFuzz must be compiled with -fsanitize=fuzzer at some point (assuming you aren’t doing blackbox fuzzing or AFL).

I strongly recommend libFuzzer though. Probably best to read the libFuzzer docs so you understand how to make a libFuzzer-based target. Once you have one, you can upload it to ClusterFuzz.

Nope, haven’t done that, wanted to see what would happen / did not understand the contept of the glue code program at that time. Perhaps this is just the resulting error then.

Maybe we should make this clearer in the docs.

Good luck and let us know if you run into other trouble.