Re: [PATCH] ceph: use the mount idmap for the owner checks in the SET_LAYOUT ioctls

[Ilya Dryomov]

On Wed, Aug 12, 2026 at 1:32 PM Xiubo Li <xiubo.li@xxxxxxxxx> wrote:
>
> Hi Ilya,
>
> I'm not sure why I couldn't find the original email of this. I checked
> the changes on lore.kernel.org.
>
> The fix looks correct to me.
>
> On an idmapped mount, using &nop_mnt_idmap compares the caller's fsuid
> against the unmapped on-disk uid directly, which would wrongly deny
> the actual mapped owner and potentially allow an unrelated caller.
> Both functions already have the struct file, so switching to
> file_mnt_idmap(file) is the right thing to do.
>
> Reviewed-by: Xiubo Li <xiubo.li@xxxxxxxxx>

Applied.

Thanks,

                Ilya

>
> Thanks
> Xiubo Li
>
> On Sun, 9 Aug 2026 at 10:33, Ilya Dryomov <idryomov@xxxxxxxxx> wrote:
> >
> > On Sat, Aug 8, 2026 at 8:31 AM Max Kellermann <max.kellermann@xxxxxxxxx> wrote:
> > >
> > > On Tue, Jul 28, 2026 at 1:31 PM Ilya Dryomov <idryomov@xxxxxxxxx> wrote:
> > > > Was there any specific reason you used nop_mnt_idmap for these checks?
> > >
> > > No, I copied that check from another filesystem, probably ext2. I had
> > > no idea what this parameter means (and I have never used idmappings).
> > > I guess the amended parameter in this patch is correct.
> >
> > Hi Xiubo,
> >
> > You reviewed Max's "ceph: add owner/capability checks for
> > CEPH_IOC_SET_LAYOUT*" patch.  Would you be able to review this fixup as
> > well?
> >
> > Thanks,
> >
> >                 Ilya