On Thu, 12 Nov 2020, Mickaël Salaün wrote:

> Cc: James Morris <jmorris@namei.org>
> Cc: Jann Horn <jannh@google.com>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Serge E. Hallyn <serge@hallyn.com>
> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
> ---
> 
> Changes since v23:
> * Always intersect access rights.  Following the filesystem change
>   logic, make ruleset updates more consistent by always intersecting
>   access rights (boolean AND) instead of combining them (boolean OR) for
>   the same layer.  This defensive approach could also help avoid user
>   space to inadvertently allow multiple access rights for the same
>   object (e.g.  write and execute access on a path hierarchy) instead of
>   dealing with such inconsistency.  This can happen when there is no
>   deduplication of objects (e.g. paths and underlying inodes) whereas
>   they get different access rights with landlock_add_rule(2).
> * Add extra checks to make sure that:
>   - there is always an (allocated) object in each used rules;
>   - when updating a ruleset with a new rule (i.e. not merging two
>     rulesets), the ruleset doesn't contain multiple layers.
> * Hide merge parameter from the public landlock_insert_rule() API.  This
>   helps avoid misuse of this function.
> * Replace a remaining hardcoded 1 with SINGLE_DEPTH_NESTING.

Jann: any chance you could review this patch again given the changes 
above?

Thanks.


-- 
James Morris
<jmorris@namei.org>