IPC scopes

Scopes are Landlock's IPC isolation primitive. Unlike filesystem and network rules, scopes are all-or-nothing — there is no per-resource rule to grant exemptions. A scope flag, when handled by a ruleset, isolates the sandboxed process from a specific kind of cross-domain IPC entirely.

Scopes require Landlock ABI 6 (Linux kernel 6.12+). See the "Scope flags" section of landlock(7) for the kernel-side definition.

What scopes can isolate

Two scope flags exist today:

C# value	Kernel constant	What it isolates
`Landlock.Scope.ABSTRACT_UNIX_SOCKET`	`LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET`	Connections into abstract Unix sockets (the `\0`-prefixed Linux-specific kind) from outside the Landlock domain are blocked. Filesystem-backed Unix sockets are unaffected.
`Landlock.Scope.SIGNAL`	`LANDLOCK_SCOPE_SIGNAL`	Signals sent into the domain by processes outside it are blocked. The sandboxed process can still signal its own children.

Both scopes are about who can talk to the sandbox from outside, not who the sandbox can talk to. The intent is to stop a sandboxed plugin or worker from being co-opted by a peer process on the same host.

For the exact kernel semantics see landlock(7) — "Scope flags".

Enabling scopes

Scopes go through the third parameter of the full CreateRuleset overload:

var sandbox = Landlock.CreateRuleset(
    fileSystem: new[] { Landlock.FileSystem.CORE },
    network:    null,
    scope:      new[]
    {
        Landlock.Scope.ABSTRACT_UNIX_SOCKET,
        Landlock.Scope.SIGNAL,
    });

sandbox
    .AddPathBeneathRule("/var/lib/myapp", Landlock.FileSystem.READ_FILE, Landlock.FileSystem.READ_DIR)
    .Enforce();

There are no per-scope rules to add — listing the scope in the ruleset is the entire configuration.

When scopes are useful

Plugin sandboxes. Stop a sandboxed plugin from binding to an abstract Unix socket that some other process on the host might unexpectedly connect to.
Multi-tenant workers. Prevent an attacker in a neighbouring container (sharing the host's abstract Unix socket namespace) from signalling the sandboxed worker.
Defense in depth. Combine with filesystem rules so a compromised sandboxed process can neither reach the filesystem nor be reached by other processes on the host.

The landlock-sample repo contains C-language examples of the same pattern.

Falling back on older kernels

On a kernel older than 6.12, Landlock.Scope.* flags are silently filtered out — see ABI versions. Add an explicit check if your security model relies on scope isolation:

if (Landlock.GetAbiVersion() < 6)
    throw new PlatformNotSupportedException(
        "This service requires Landlock ABI ≥ 6 (Linux 6.12+) for IPC scopes.");

Cross-reference

landlock(7) — Scope flags
Kernel docs — Landlock scoping
Landlock ABI 6 announcement — kernel 6.12 release notes.

Referenced by

quick-start