Re: [PATCH v7 6/6] mm/memfd: security hook for memfd_create

[Paul Moore]

On Fri, Dec 9, 2022 at 11:05 AM <jeffxu@xxxxxxxxxxxx> wrote:
>
> From: Jeff Xu <jeffxu@xxxxxxxxxx>
>
> The new security_memfd_create allows lsm to check flags of
> memfd_create.
>
> The security by default system (such as chromeos) can use this
> to implement system wide lsm to allow only non-executable memfd
> being created.
>
> Signed-off-by: Jeff Xu <jeffxu@xxxxxxxxxx>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> ---
>  include/linux/lsm_hook_defs.h | 1 +
>  include/linux/lsm_hooks.h     | 4 ++++
>  include/linux/security.h      | 6 ++++++
>  mm/memfd.c                    | 5 +++++
>  security/security.c           | 5 +++++
>  5 files changed, 21 insertions(+)

We typically require at least one in-tree LSM implementation to
accompany a new LSM hook.  Beyond simply providing proof that the hook
has value, it helps provide a functional example both for reviewers as
well as future LSM implementations.  Also, while the BPF LSM is
definitely "in-tree", its nature is such that the actual
implementation lives out-of-tree; something like SELinux, AppArmor,
Smack, etc. are much more desirable from an in-tree example
perspective.

-- 
paul-moore.com