[PATCH v13 01/10] landlock: Add IOCTL access right for character and block devices

[Günther Noack]

On Fri, Apr 05, 2024 at 02:17:29PM -0400, Kent Overstreet wrote:
> On Fri, Apr 05, 2024 at 06:22:52PM +0200, Günther Noack wrote:
> > Kent, Amir:
> > 
> > Is it intentional that the new FS_IOC_GETUUID and FS_IOC_GETFSSYSFSPATH IOCTLs
> > can fall back to a IOCTL implementation in struct file_operations?  I found this
> > remark by Amir which sounded vaguely like it might have been on purpose?  Did I
> > understand that correctly?
> > 
> > https://lore.kernel.org/lkml/CAOQ4uxjvEL4P4vV5SKpHVS5DtOwKpxAn4n4+Kfqawcu+H-MC5g@mail.gmail.com/
> > 
> > Otherwise, I am happy to send a patch to make it non-extensible (the impls in
> > fs/ioctl.c would need to return -ENOTTY).  This would let us reason better about
> > the safety of these IOCTLs for IOCTL security policies enforced by the Landlock
> > LSM. (Some of these file_operations IOCTL implementations do stuff before
> > looking at the cmd number.)
> 
> They're not supposed to be extensible - the generic implementations are
> all we need.

Thank you for confirming, Kent -- I sent you a small patch as part of the next
version of the Landlock patch series:
https://lore.kernel.org/all/20240405214040.101396-2-gnoack@google.com/

—Günther