On Mon, Jun 27, 2022 at 8:11 AM Christian Brauner [off-list ref] wrote:

On Thu, Jun 23, 2022 at 11:21:37PM -0400, Paul Moore wrote:

...

quoted

This is one of the reasons why I usually like to see at least one LSM
implementation to go along with every new/modified hook.  The
implementation forces you to think about what information is necessary
to perform a basic access control decision; sometimes it isn't always
obvious until you have to write the access control :)

I spoke to Frederick at length during LSS and as I've been given to
understand there's a eBPF program that would immediately use this new
hook. Now I don't want to get into the whole "Is the eBPF LSM hook
infrastructure an LSM" but I think we can let this count as a legitimate
first user of this hook/code.

Yes, for the most part I don't really worry about the "is a BPF LSM a
LSM?" question, it's generally not important for most discussions.
However, there is an issue unique to the BPF LSMs which I think is
relevant here: there is no hook implementation code living under
security/.  While I talked about a hook implementation being helpful
to verify the hook prototype, it is also helpful in providing an
in-tree example for other LSMs; unfortunately we don't get that same
example value when the initial hook implementation is a BPF LSM.

-- 
paul-moore.com