seccompy

Dependency-free Python bindings for Linux seccomp-BPF syscall filtering. Filters are assembled in pure Python from symbolic instructions, checked against the native architecture to block ABI confusion, and installed through seccomp(2) with prctl(PR_SET_NO_NEW_PRIVS), so no compiler, libbpf or privileges are needed.

Requires Python 3.10+ and Linux 3.17+ on x86_64 or aarch64.

Install

pip install seccompy

Usage

import errno

from seccompy import Action, Filter

filt = Filter(default=Action.ALLOW)
filt.errno("openat", errno.EACCES)
filt.kill("ptrace")
filt.log("mount")
filt.load()

# openat now fails with EACCES for this thread and its children,
# ptrace kills the process, mount is allowed but logged

Rules can also match on 64-bit syscall arguments:

filt.errno("write", errno.EIO, args={0: 1})  # deny write() on fd 1 only

seccompy.supported() reports whether the running kernel can install filters, seccompy.action_supported(Action.X) probes a return action and seccompy.flag_supported(FilterFlag.X) probes a load flag. The compiled BPF program is available as filt.program for inspection, and seccompy.testing.probe() runs a callable under a filter in a forked child to preview enforcement.

Documentation

• API: docstrings in src/seccompy/, mostly filter.py
• seccomp reference: https://docs.kernel.org/userspace-api/seccomp_filter.html
• seccomp(2) man page: https://man7.org/linux/man-pages/man2/seccomp.2.html

License: 0BSD.