Landlock Class

Entry point for the binding. A Landlock instance represents a ruleset under construction; the static members check kernel support and create rulesets, and the instance members add rules and enforce the sandbox on the current thread.

Definition

Namespace: Sandbox

public class Landlock

A ruleset declares which access rights it handles — those rights become denied by default. Rules added with AddPathBeneathRule and AddPortRule re-grant access to specific resources, and Enforce binds the ruleset to the current thread.

Remarks

The class mirrors the three Landlock syscalls in order: landlock_create_ruleset → landlock_add_rule → landlock_restrict_self. An instance is mutable while you add rules and becomes inert once enforced — calling an Add* method after Enforce throws. The kernel ruleset is a file descriptor; discarding the instance without enforcing releases it. See API overview for the full lifecycle.

Methods

Name	Description
`IsSupported()`	Returns whether Landlock is usable on the current OS, architecture, and kernel.
`GetAbiVersion()`	Returns the kernel's supported Landlock ABI version, or a negative value when unsupported.
`CreateRuleset(...)`	Builds a ruleset declaring which filesystem, network, and scope rights it handles.
`AddPathBeneathRule(string, FileSystem[])`	Re-grants filesystem access for a directory tree. Returns `this` for chaining.
`AddPortRule(int, Network[])`	Re-grants TCP access for a port. Returns `this` for chaining.
`Enforce(...)`	Applies the ruleset to the current thread. Irrevocable.

IsSupported

public static bool IsSupported()

Returns true only when the host OS is Linux, the process architecture is x86-64, and landlock_create_ruleset reports an ABI version ≥ 1. Safe to call on any platform — non-Linux hosts return false. Gate every other call on this result so your code stays portable.

Maps to landlock_create_ruleset (version query).

GetAbiVersion

public static int GetAbiVersion()

Returns the running kernel's supported Landlock ABI version (≥ 1), or a negative value when Landlock is unavailable (kernel < 5.13, or Landlock excluded from lsm=). It is a single syscall and safe to call repeatedly. Use it for feature negotiation — see ABI versions.

Maps to landlock_create_ruleset (version query).

CreateRuleset

public static Landlock CreateRuleset(params Landlock.FileSystem[] fileSystem);

public static Landlock CreateRuleset(params Landlock.Network[] network);

public static Landlock CreateRuleset(
    Landlock.FileSystem[] fileSystem,
    Landlock.Network[]    network,
    Landlock.Scope[]      scope = null);

Creates a new ruleset declaring which access rights it handles. Three overloads match the three resource categories: filesystem only, network only, or all three together. Pass null to a category to leave it untouched by the sandbox. Flags newer than the running kernel's ABI are silently dropped.

fileSystem — the FileSystem rights the ruleset handles.
network — the Network rights the ruleset handles.
scope — the Scope IPC isolation flags; optional.

Maps to landlock_create_ruleset.

AddPathBeneathRule

public Landlock AddPathBeneathRule(string parentPath, params Landlock.FileSystem[] allowedActions)

Re-grants the given filesystem rights for parentPath and everything beneath it. parentPath must be an existing directory. The granted actions must be a subset of the rights declared in CreateRuleset. Returns the same instance for chaining. Throws if called after Enforce.

parentPath — directory whose tree the rule applies to.
allowedActions — the FileSystem rights to re-grant.

Maps to landlock_add_rule(..., PATH_BENEATH, ...). See the filesystem rules guide.

AddPortRule

public Landlock AddPortRule(int port, params Landlock.Network[] allowedActions)

Re-grants TCP access for a single port number. The granted actions must be a subset of the network rights declared in CreateRuleset. Returns the same instance for chaining. Throws if called after Enforce.

port — the TCP port number the rule applies to.
allowedActions — the Network rights to re-grant.

Maps to landlock_add_rule(..., NET_PORT, ...). See the network rules guide.

Enforce

public void Enforce(
    bool disableDenyLogging = false,
    bool enableChildDenyLogging = false,
    bool disabledNestedDomainsLogging = false)

Applies the ruleset to the current thread and its descendants. The call sets PR_SET_NO_NEW_PRIVS, invokes landlock_restrict_self, and closes the ruleset file descriptor. The restriction is irrevocable — there is no way to widen the sandbox afterwards. Idempotent on the same instance; enforcing a different instance layers additional restrictions on top.

The three optional flags map to ABI 7 (kernel 6.13) logging controls and are silently ignored on older kernels.

disableDenyLogging — stop logging denials from this domain in the current execution (LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF).
enableChildDenyLogging — log denials in child processes started by a new execve (LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON).
disabledNestedDomainsLogging — stop logging denials from nested layered domains (LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF).

Maps to prctl(PR_SET_NO_NEW_PRIVS) + landlock_restrict_self. See the enforcing and deny logging guides.

Applies to

Sandbox.dll — Linux only (x86-64, kernel ≥ 5.13). See the guides.