This is a note to let you know that I've just added the patch titled
memfd: check for non-NULL file_seals in memfd_create() syscall
to the 6.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
memfd-check-for-non-null-file_seals-in-memfd_create-syscall.patch
and it can be found in the queue-6.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 935d44acf621aa0688fef8312dec3e5940f38f4e Mon Sep 17 00:00:00 2001
From: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
Date: Wed, 7 Jun 2023 15:24:27 +0200
Subject: memfd: check for non-NULL file_seals in memfd_create() syscall
From: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
commit 935d44acf621aa0688fef8312dec3e5940f38f4e upstream.
Ensure that file_seals is non-NULL before using it in the memfd_create()
syscall. One situation in which memfd_file_seals_ptr() could return a
NULL pointer when CONFIG_SHMEM=n, oopsing the kernel.
Link: https://lkml.kernel.org/r/20230607132427.2867435-1-roberto.sassu@xxxxxxxxxxxxxxx
Fixes: 47b9012ecdc7 ("shmem: add sealing support to hugetlb-backed memfd")
Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
Cc: Marc-Andr Lureau <marcandre.lureau@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/memfd.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
--- a/mm/memfd.c
+++ b/mm/memfd.c
@@ -375,12 +375,15 @@ SYSCALL_DEFINE2(memfd_create,
inode->i_mode &= ~0111;
file_seals = memfd_file_seals_ptr(file);
- *file_seals &= ~F_SEAL_SEAL;
- *file_seals |= F_SEAL_EXEC;
+ if (file_seals) {
+ *file_seals &= ~F_SEAL_SEAL;
+ *file_seals |= F_SEAL_EXEC;
+ }
} else if (flags & MFD_ALLOW_SEALING) {
/* MFD_EXEC and MFD_ALLOW_SEALING are set */
file_seals = memfd_file_seals_ptr(file);
- *file_seals &= ~F_SEAL_SEAL;
+ if (file_seals)
+ *file_seals &= ~F_SEAL_SEAL;
}
fd_install(fd, file);
Patches currently in stable-queue which might be from roberto.sassu@xxxxxxxxxx are
queue-6.3/memfd-check-for-non-null-file_seals-in-memfd_create-syscall.patch
