On Wed, Dec 9, 2020 at 8:28 PM Mickaël Salaün [off-list ref] wrote:

A Landlock ruleset is mainly a red-black tree with Landlock rules as
nodes.  This enables quick update and lookup to match a requested
access, e.g. to a file.  A ruleset is usable through a dedicated file
descriptor (cf. following commit implementing syscalls) which enables a
process to create and populate a ruleset with new rules.

A domain is a ruleset tied to a set of processes.  This group of rules
defines the security policy enforced on these processes and their future
children.  A domain can transition to a new domain which is the
intersection of all its constraints and those of a ruleset provided by
the current process.  This modification only impact the current process.
This means that a process can only gain more constraints (i.e. lose
accesses) over time.

Cc: James Morris <jmorris@namei.org>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <redacted>
Cc: Serge E. Hallyn <serge@hallyn.com>
Signed-off-by: Mickaël Salaün <redacted>

Yeah, the layer stack stuff in this version looks good to me. :)

Reviewed-by: Jann Horn <jannh@google.com>