FAILED: patch "[PATCH] memfd: check for non-NULL file_seals in memfd_create()" failed to apply to 6.1-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

The patch below does not apply to the 6.1-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@xxxxxxxxxxxxxxx>.

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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 935d44acf621aa0688fef8312dec3e5940f38f4e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023062314-saffron-portly-6c2a@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

>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: [PATCH] memfd: check for non-NULL file_seals in memfd_create()
 syscall

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>

diff --git a/mm/memfd.c b/mm/memfd.c
index 69b90c31d38c..e763e76f1106 100644
--- a/mm/memfd.c
+++ b/mm/memfd.c
@@ -371,12 +371,15 @@ 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);