oxsb

Cross-platform sandbox wrapper that runs commands inside OS-level sandboxes using a unified YAML configuration. The backend is selected automatically based on the detected OS.

Platform	Backend	Mechanism
macOS	seatbelt	sandbox-exec with a generated .sb profile
Linux	landlock	Landlock LSM via the landlock crate
WSL2	bubblewrap	bwrap with bind mounts
Any	none	Pass-through (no sandboxing)

Installation

Cargo

cargo install --path .

Nix (flake)

nix profile install github:daaa1k/oxsb

Home Manager module

# flake.nix
inputs.oxsb.url = "github:daaa1k/oxsb";

# home.nix
{ inputs, ... }: {
  imports = [ inputs.oxsb.homeManagerModules.default ];
  programs.oxsb = {
    enable = true;
    settings = {
      backend.auto = true;
      write_allow = [
        { path = "$HOME/.config"; }
        { path = "/tmp"; }
      ];
      env.set.IN_SANDBOX = "1";
    };
  };
}

Usage

# Run a command inside the sandbox using the default config
oxsb -- claude --help

# Specify a custom config file
oxsb --config /path/to/config.yaml -- my-command

# Override the backend
oxsb --backend landlock -- my-command

# Preview the sandbox command without executing
oxsb --dry-run -- my-command

# Verbose output (logs skipped optional paths, etc.)
oxsb --verbose -- my-command

Configuration

Default location: ~/.config/oxsb/config.yaml

backend:
  auto: true          # auto-detect based on OS (default)
  # linux: landlock   # override per-platform
  # wsl2: bubblewrap
  # macos: seatbelt

write_allow:
  - path: "$HOME/.config"
  - path: "$HOME/.cache"
  - path: "$HOME/.local/share"
  - path: "$HOME/.local/state"
    create: true              # create directory if missing
  - path: "$HOME/.claude.json"
    file: true                # treat as a file, not a directory
    touch: true               # create empty file if missing
  - path: "/tmp"
  - path: "/nix"
    optional: true            # silently skip if path does not exist

bubblewrap:
  extra_args: ["--share-net"] # extra flags passed to bwrap

seatbelt:
  generate_profile: true      # generate .sb profile from write_allow

env:
  set:
    IN_SANDBOX: "1"           # inject environment variables

Path variables

The following variables are expanded in path values:

Variable	Expands to
$HOME	Home directory
$CWD	Current working directory
$XDG_CONFIG_HOME	$HOME/.config
$XDG_CACHE_HOME	$HOME/.cache
$XDG_DATA_HOME	$HOME/.local/share
$XDG_STATE_HOME	$HOME/.local/state
$XDG_RUNTIME_DIR	Runtime directory (Linux)

Both $VAR and ${VAR} syntax are supported.

PathEntry options

Field	Type	Default	Description
path	string	—	Path to allow writes to (variables expanded)
optional	bool	false	Skip silently if path does not exist
create	bool	false	Create as directory if missing
file	bool	false	Treat as a file (affects seatbelt profile rule)
touch	bool	false	Create as empty file if missing (requires file: true)

Development

cargo build
cargo test
cargo clippy
cargo fmt

License

MIT