# The type system is the seccomp profile

> On main since rc2: The type system is the seccomp profile.

Source: https://kern-lang.eu/releases/type-system-is-the-seccomp-profile

On main since rc2

## Release notes

Every Kern binary now seals itself, before user code runs, to a seccomp-BPF filter that permits only the syscalls its capability set grants, and that set is derived by the **compiler** from the program's own types. A program that never mints `Cap<Net>` gets a kernel that denies `socket()`; one that never mints `Cap<Process>` cannot `execve`. E0404 already made ambient authority a compile error; the sandbox makes the same guarantee kernel-enforced at runtime, so a later RCE cannot exceed what the type system permitted.

Nothing to configure, installed with `NO_NEW_PRIVS` so a spawned process inherits the filter. Self-hosting survives the seal: the compiler seals itself to `FS|PROCESS` and still bootstraps the next generation, running clang under the inherited filter. Landlock completes the filesystem story: the seccomp gate decides _whether_ a program may open files, `KERN_SANDBOX_FS_RO`/`RW` decide _which paths_, layered on the seal and a clean no-op on kernels without Landlock.