oss-fuzz/docs/fuzzer_environment.md

Fuzzer environment on ClusterFuzz

Your fuzzers will be run on ClusterFuzz (Linux environment) with some restrictions.

Current working directory

You cannot make any assumptions about the current working directory of your fuzzer. If you need to load data files, please use argv[0] to get the directory where your fuzzer executable is located. This may change in the near future.

Filesystem

Everything except /tmp is read-only, including the directory that your fuzzer executable lives in. Note that /tmp is limited in size (64MB).

Network access

There will be no network interfaces available (not even loopback).