littlesnitch-linux

Little Snitch for Linux

This repository contains the Open Source part of Little Snitch for Linux. It consists of:

• The Rust crate ebpf, which contains all eBPF programs attached to the Linux kernel.
• The Rust crate common, which contains all types and functions shared between kernel and user space.
• The Rust crate demo-runner. This is a user-space program which loads the eBPF programs into the kernel and demonstrates how to share data with these programs via eBPF maps. It loads two blocklists for demonstration: blocked_hosts.txt and blocked_domains.txt.
• webroot: This is the JavaScript web UI of Little Snitch for Linux.

All code in this public repository is Open Source and distributed under the GNU General Public License, Version 2. It is part of Little Snitch for Linux, a free product by Objective Development. The full product also includes proprietary code that is not part of this repository. While Little Snitch for Linux is free to use, that proprietary portion is not Open Source.

Prerequisites

1. stable rust toolchains: rustup toolchain install stable
2. the pinned nightly toolchain for the eBPF build, e.g. rustup toolchain install nightly-2026-07-07 --component rust-src (see ebpf/rust-toolchain.toml for the currently pinned version)
3. bpf-linker: cargo install bpf-linker --locked (version 0.10.3 is known to work)
4. the clang C/C++ compiler

Note: eBPF is a bit fragile. The kernel verifier may reject the program after changes in the verifier itself, in the Rust compiler or in bpf-linker. The nightly toolchain used for the eBPF build is therefore pinned in ebpf/rust-toolchain.toml; the build scripts of the crates embedding the eBPF program (demo-runner and the daemon) read the pin from there and pass it to rustup run explicitly. This code is known to pass the verifier on Linux kernels 6.12 to 7.2.0 when compiled with the pinned nightly-2026-07-07 and bpf-linker 0.10.3. Other versions may or may not work.

Build & Run

Use cargo build, cargo check, etc. as normal. Run your program with:

cargo run --release

Cargo build scripts automatically build the eBPF programs and include them in the binary.

eBPF

All eBPF code is distributed under the terms of the GNU General Public License, Version 2.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the GPL-2 license, shall be licensed as above, without any additional terms or conditions.