[PATCH 1/3] lsm,io_uring: add LSM hooks for the new uring_cmd file op

[Paul Moore]

On Tue, Aug 23, 2022 at 2:53 AM Greg Kroah-Hartman
<gregkh at linuxfoundation.org> wrote:
> On Mon, Aug 22, 2022 at 05:21:07PM -0400, Paul Moore wrote:
> > From: Luis Chamberlain <mcgrof at kernel.org>
> >
> > io-uring cmd support was added through ee692a21e9bf ("fs,io_uring:
> > add infrastructure for uring-cmd"), this extended the struct
> > file_operations to allow a new command which each subsystem can use
> > to enable command passthrough. Add an LSM specific for the command
> > passthrough which enables LSMs to inspect the command details.
> >
> > This was discussed long ago without no clear pointer for something
> > conclusive, so this enables LSMs to at least reject this new file
> > operation.
> >
> > [0] https://lkml.kernel.org/r/8adf55db-7bab-f59d-d612-ed906b948d19@schaufler-ca.com
> >
> > Fixes: ee692a21e9bf ("fs,io_uring: add infrastructure for uring-cmd")
>
> You are not "fixing" anything, you are adding new functionality.
> Careful with using "Fixes:" for something like this, you will trigger
> the bug-detection scripts and have to fend off stable bot emails for a
> long time for stuff that should not be backported to stable trees.

This patch, as well as the SELinux and (soon to come) Smack hook
implementations, fix a LSM access control regression that occured when
the IORING_OP_URING_CMD functionality was merged in v5.19.  You may
disagree about this being a regression Greg, but there are at least
three people with their name on this patch that believe it is
important: Luis (patch author), Jens (io_uring maintainer), and myself
(LSM, SELinux maintainer).

--
paul-moore.com