FAILED: patch "[PATCH] hugetlbfs: enforce F_SEAL_EXEC in setattr" failed to apply to 7.3-stable tree

FAILED: patch "[PATCH] hugetlbfs: enforce F_SEAL_EXEC in setattr" failed to apply to 7.3-stable tree

[Sasha Levin]

The patch below does not apply to the 7.3-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-7.3.y
git checkout FETCH_HEAD
git cherry-pick -x b7f570e7cea761ec7eb4a3a9557a3a082d14e88c
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261109200122-failed-7.3-b7f570e7cea7@kernel.org' --subject-prefix 'PATCH 7.3.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From b7f570e7cea761ec7eb4a3a9557a3a082d14e88c Mon Sep 17 00:00:00 2001
From: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
Date: Thu, 29 Oct 2026 11:43:26 +0100
Subject: [PATCH] hugetlbfs: enforce F_SEAL_EXEC in setattr

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@vger.kernel.org
Signed-off-by: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
Link: https://patch.msgid.link/20260629180247.2343229-1-eva.kurchatova@virtuozzo.com
Acked-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Tested-by: Gregory Price (Meta) <gourry@gourry.net>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
[ david: use common helper; fixup Fixes:; check only regular files ]
Acked-by: Oscar Salvador <osalvador@suse.de>
Link: https://patch.msgid.link/20261029-fixes_shmem-v4-5-392fc715d8f6@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
---
 fs/hugetlbfs/inode.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 01c4d6f44ebe0..02e0a65d596d8 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -28,6 +28,7 @@
 #include <linux/folio_batch.h>
 #include <linux/fs_parser.h>
 #include <linux/mman.h>
+#include <linux/memfd.h>
 #include <linux/slab.h>
 #include <linux/dnotify.h>
 #include <linux/statfs.h>
@@ -840,6 +841,13 @@ static int hugetlbfs_setattr(const struct mnt_idmap *idmap,
 	if (error)
 		return error;
 
+	if (S_ISREG(inode->i_mode) && (ia_valid & ATTR_MODE)) {
+		error = memfd_check_seals_mode(info->seals, inode->i_mode,
+					       attr->ia_mode);
+		if (error)
+			return error;
+	}
+
 	trace_hugetlbfs_setattr(inode, dentry, attr);
 
 	if (ia_valid & ATTR_SIZE) {
-- 
2.53.0

[PATCH 7.3.y] hugetlbfs: enforce F_SEAL_EXEC in setattr

[Sasha Levin]

From: Eva Kurchatova <eva.kurchatova@virtuozzo.com>

[ Upstream commit b7f570e7cea761ec7eb4a3a9557a3a082d14e88c ]

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@vger.kernel.org
Signed-off-by: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
Link: https://patch.msgid.link/20260629180247.2343229-1-eva.kurchatova@virtuozzo.com
Acked-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Tested-by: Gregory Price (Meta) <gourry@gourry.net>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
[ david: use common helper; fixup Fixes:; check only regular files ]
Acked-by: Oscar Salvador <osalvador@suse.de>
Link: https://patch.msgid.link/20261029-fixes_shmem-v4-5-392fc715d8f6@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
[ sashal: Replaced the unavailable memfd_check_seals_mode() helper with an equivalent inline check. ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hugetlbfs/inode.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 7611a8470ea26..2eca1855e0973 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -841,6 +841,11 @@ static int hugetlbfs_setattr(struct mnt_idmap *idmap,
 	if (error)
 		return error;
 
+	if (S_ISREG(inode->i_mode) && (ia_valid & ATTR_MODE) &&
+	    (info->seals & F_SEAL_EXEC) &&
+	    ((inode->i_mode ^ attr->ia_mode) & 0111))
+		return -EPERM;
+
 	trace_hugetlbfs_setattr(inode, dentry, attr);
 
 	if (ia_valid & ATTR_SIZE) {
-- 
2.53.0