[PATCH v9 02/12] landlock: Allow filesystem layout changes for domains without such rule type

[Mickaël Salaün]

Hi Konstantin,

I think this patch series is almost ready. Here is a first batch of 
review, I'll send more next week.


I forgot to update the documentation. Can you please squash the 
following patch into this one?


diff --git a/Documentation/userspace-api/landlock.rst 
b/Documentation/userspace-api/landlock.rst
index 980558b879d6..fc2be89b423f 100644
--- a/Documentation/userspace-api/landlock.rst
+++ b/Documentation/userspace-api/landlock.rst
@@ -416,9 +416,9 @@ Current limitations
  Filesystem topology modification
  --------------------------------

-As for file renaming and linking, a sandboxed thread cannot modify its
-filesystem topology, whether via :manpage:`mount(2)` or
-:manpage:`pivot_root(2)`.  However, :manpage:`chroot(2)` calls are not 
denied.
+Threads sandboxed with filesystem restrictions cannot modify filesystem
+topology, whether via :manpage:`mount(2)` or :manpage:`pivot_root(2)`.
+However, :manpage:`chroot(2)` calls are not denied.

  Special filesystems
  -------------------


On 16/01/2023 09:58, Konstantin Meskhidze wrote:
> From: Mickaël Salaün <mic at digikod.net>
> 
> Allow mount point and root directory changes when there is no filesystem
> rule tied to the current Landlock domain.  This doesn't change anything
> for now because a domain must have at least a (filesystem) rule, but
> this will change when other rule types will come.  For instance, a
> domain only restricting the network should have no impact on filesystem
> restrictions.
> 
> Add a new get_current_fs_domain() helper to quickly check filesystem
> rule existence for all filesystem LSM hooks.
> 
> Remove unnecessary inlining.
> 
> Signed-off-by: Mickaël Salaün <mic at digikod.net>
> ---
> 
> Changes since v8:
> * Refactors get_handled_fs_accesses().
> * Adds landlock_get_raw_fs_access_mask() helper.
>