With seccomp, you have syscall filtering. The bits that are left exposed are largely around mm, and depending on how the sandbox works, non-syscall APIs like io

With seccomp, you have syscall filtering. The bits that are left exposed are largely around mm, and depending on how the sandbox works, non-syscall APIs like io_uring. It essentially actuates kernel APIs to sandbox, and then redirects a number of APIs to use userspace reimplementations.