[PATCH v13 10/10] fs/ioctl: Add a comment to keep the logic in sync with the Landlock LSM

[Paul Moore]

On Thu, Mar 28, 2024 at 8:11 AM Mickaël Salaün <mic at digikod.net> wrote:
> On Wed, Mar 27, 2024 at 01:10:40PM +0000, Günther Noack wrote:
> > Landlock's IOCTL support needs to partially replicate the list of
> > IOCTLs from do_vfs_ioctl().  The list of commands implemented in
> > do_vfs_ioctl() should be kept in sync with Landlock's IOCTL policies.
> >
> > Signed-off-by: Günther Noack <gnoack at google.com>
> > ---
> >  fs/ioctl.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/fs/ioctl.c b/fs/ioctl.c
> > index 1d5abfdf0f22..661b46125669 100644
> > --- a/fs/ioctl.c
> > +++ b/fs/ioctl.c
> > @@ -796,6 +796,9 @@ static int ioctl_get_fs_sysfs_path(struct file *file, void __user *argp)
> >   *
> >   * When you add any new common ioctls to the switches above and below,
> >   * please ensure they have compatible arguments in compat mode.
> > + *
> > + * The commands which are implemented here should be kept in sync with the IOCTL
> > + * security policies in the Landlock LSM.
>
> Suggestion:
> "with the Landlock IOCTL security policy defined in security/landlock/fs.c"

We really shouldn't have any comments or code outside of the security/
directory that reference a specific LSM implementation.  I'm sure
there are probably a few old comments referring to SELinux, but those
are bugs as far as I'm concerned (if anyone spots one, please let me
know or send me a patch!).

How about the following?

"The LSM list should also be notified of any command additions or
changes as specific LSMs may be affected."

-- 
paul-moore.com