From 5a7090ccc242ab009ee7769e9d7fad6644dbe9bd Mon Sep 17 00:00:00 2001
From: Namjae Jeon <linkinjeon@kernel.org>
Date: Wed, 3 May 2023 08:51:51 +0900
Subject: [PATCH] ksmbd: call rcu_barrier() in ksmbd_server_exit()
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@vger.kernel.org
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-20477
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ksmbd/server.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/ksmbd/server.c b/fs/ksmbd/server.c
index 0d8242789dc8..cd8a873347a7 100644
--- a/fs/ksmbd/server.c
+++ b/fs/ksmbd/server.c
@@ -606,6 +606,7 @@ static int __init ksmbd_server_init(void)
static void __exit ksmbd_server_exit(void)
{
ksmbd_server_shutdown();
+ rcu_barrier();
ksmbd_release_inode_hash();
}
--
GitLab