Re: [PATCH v2 05/14] hugetlbfs: enforce F_SEAL_EXEC in setattr
From: Muchun Song
Date: Tue Oct 27 2026 - 09:27:17 EST
> On Oct 27, 2026, at 21:03, David Hildenbrand (Arm) <david@xxxxxxxxxx> wrote:
>
> From: Eva Kurchatova <eva.kurchatova@xxxxxxxxxxxxx>
>
> F_SEAL_EXEC is enforced by shmem_setattr(), but hugetlbfs_setattr() does
> not check it. As a result, fchmod() can change the execute bits of a
> sealed hugetlbfs memfd.
>
> Use memfd_check_seals_mode() in hugetlbfs_setattr() to reject changes
> to execute bits when F_SEAL_EXEC is set.
>
> This also fixes the memfd_test hugetlbfs SEAL-EXEC subtest, where
> fchmod() incorrectly succeeded after applying F_SEAL_EXEC.
>
> Fixes: 6fd7353829ca ("mm/memfd: add F_SEAL_EXEC")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Eva Kurchatova <eva.kurchatova@xxxxxxxxxxxxx>
> Link: https://patch.msgid.link/20260629180247.2343229-1-eva.kurchatova@xxxxxxxxxxxxx
> Acked-by: Pedro Falcato <pfalcato@xxxxxxx>
> Acked-by: Kiryl Shutsemau (Meta) <kas@xxxxxxxxxx>
> Acked-by: Zi Yan <ziy@xxxxxxxxxx>
> Tested-by: Gregory Price (Meta) <gourry@xxxxxxxxxx>
> [ david: use common helper; fixup Fixes:; check only regular files ]
> Signed-off-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>
Reviewed-by: Muchun Song <muchun.song@xxxxxxxxx>
Thanks.