All of
 help / color / mirror / Atom feed
From: Paul Moore <>
To: "Mickaël Salaün" <>
Cc: James Morris <>,
	"Serge E . Hallyn" <>,
	Alejandro Colomar <>,
	Jonathan Corbet <>,
	Kees Cook <>,
	Michael Kerrisk <>,,
Subject: Re: [PATCH v1] landlock: Explain how to support Landlock
Date: Thu, 12 May 2022 18:03:15 -0400	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Thu, May 12, 2022 at 8:08 AM Mickaël Salaün <> wrote:
> Let's help users by documenting how to enable and check for Landlock in
> the kernel and the running system.  The userspace-api section may not be
> the best place for this but it still makes sense to put all the user
> documentation at the same place.
> Cc: Paul Moore <>
> Signed-off-by: Mickaël Salaün <>
> Link:
> ---
>  Documentation/userspace-api/landlock.rst | 26 ++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> diff --git a/Documentation/userspace-api/landlock.rst b/Documentation/userspace-api/landlock.rst
> index 7b4fe6218132..e69dbddcc191 100644
> --- a/Documentation/userspace-api/landlock.rst
> +++ b/Documentation/userspace-api/landlock.rst
> @@ -388,6 +388,32 @@ Starting with the Landlock ABI version 2, it is now possible to securely
>  control renaming and linking thanks to the new `LANDLOCK_ACCESS_FS_REFER`
>  access right.
> +Landlock support
> +================
> +
> +Kernel configuration
> +--------------------

I would suggest changing the section name to "Kernel build
configuration" to make it clear the instructions below need to be done
at build time.

> +Landlock can be supported since Linux 5.13 but it must be configured in the

I would suggest rephrasing the first part of this sentence slightly:

"Landlock was first introduced in Linux v5.13 but it must be ..."

> +kernel with `CONFIG_SECURITY_LANDLOCK=y`, and it should be enabled at boot time

CONFIG_LSM is a Kconfig build time variable not a runtime command line
variable, yes?

> +with `CONFIG_LSM=landlock,[...]`.  The `[...]` must be replaced with the list
> +of LSMs that may be useful for the running system (see the `CONFIG_LSM` help).
> +
> +Running system configuration
> +----------------------------

This is nit-picky, but I would suggest a section name of "Kernel
command line configuration".

> +If the running kernel doesn't have `landlock` in `CONFIG_LSM`, then we can
> +still enable it by adding `lsm=landlock,[...]` to
> +Documentation/admin-guide/kernel-parameters.rst. The `[...]` must be replaced
> +with the list of LSMs that may be useful for the running system (see the
> +`CONFIG_LSM` help).
> +
> +Running system check
> +--------------------
> +
> +We can check that Landlock is enabled by looking for "landlock: Up and running"
> +in kernel logs: `dmesg | grep landlock`

I would suggest moving the "Running system check" section up closer to
the top of the documentation, perhaps right before the "Landlock
rules" section.  My thinking is that it is better to mention this as
soon as possible in the doc so that users can verify Landlock is
present and functioning before trying any of the code examples and
failing.  I think it is okay to leave the "how to enable Landlock"
sections at the bottom and simply refer to them in the "system check"


  reply	other threads:[~2022-05-12 22:03 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-12 12:08 Mickaël Salaün
2022-05-12 22:03 ` Paul Moore [this message]
2022-05-13  9:21   ` Mickaël Salaün

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \ \ \ \
    --subject='Re: [PATCH v1] landlock: Explain how to support Landlock' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.