oss-fuzz/docs/fuzzer_environment.md

Fuzzer environment on ClusterFuzz

Your fuzz targets will be run on a Google Compute Engine VM (Linux) with some security restrictions.

Current working directory

You should not make any assumptions about the current working directory of your fuzz target. If you need to load data files, please use argv[0] to get the directory where your fuzz target executable is located.

File system

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

/dev is also unavailable.

Network access

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