This is a note to let you know that I've just added the patch titled
ksmbd: call rcu_barrier() in ksmbd_server_exit()
to the 5.15-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:
ksmbd-call-rcu_barrier-in-ksmbd_server_exit.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From eb307d09fe15844fdaebeb8cc8c9b9e925430aa5 Mon Sep 17 00:00:00 2001
From: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Date: Wed, 3 May 2023 08:51:51 +0900
Subject: ksmbd: call rcu_barrier() in ksmbd_server_exit()
From: Namjae Jeon <linkinjeon@xxxxxxxxxx>
commit eb307d09fe15844fdaebeb8cc8c9b9e925430aa5 upstream.
racy issue is triggered the bug by racing between closing a connection
and rmmod. In ksmbd, rcu_barrier() is not called at module unload time,
so nothing prevents ksmbd from getting unloaded while it still has RCU
callbacks pending. It leads to trigger unintended execution of kernel
code locally and use to defeat protections such as Kernel Lockdown
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: zdi-disclosures@xxxxxxxxxxxxxx # ZDI-CAN-20477
Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ksmbd/server.c | 1 +
1 file changed, 1 insertion(+)
--- a/fs/ksmbd/server.c
+++ b/fs/ksmbd/server.c
@@ -611,6 +611,7 @@ err_unregister:
static void __exit ksmbd_server_exit(void)
{
ksmbd_server_shutdown();
+ rcu_barrier();
ksmbd_release_inode_hash();
}
Patches currently in stable-queue which might be from linkinjeon@xxxxxxxxxx are
queue-5.15/ksmbd-fix-memleak-in-session-setup.patch
queue-5.15/ksmbd-fix-null-pointer-dereference-in-smb2_get_info_filesystem.patch
queue-5.15/ksmbd-call-rcu_barrier-in-ksmbd_server_exit.patch
