From eb307d09fe15844fdaebeb8cc8c9b9e925430aa5 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Wed, 3 May 2023 08:51:51 +0900 Subject: [PATCH] ksmbd: call rcu_barrier() in ksmbd_server_exit() 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 Signed-off-by: Steve French --- fs/ksmbd/server.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ksmbd/server.c b/fs/ksmbd/server.c index 2ebf6985a88d..f9b2e0f19b03 100644 --- a/fs/ksmbd/server.c +++ b/fs/ksmbd/server.c @@ -606,6 +606,7 @@ err_unregister: static void __exit ksmbd_server_exit(void) { ksmbd_server_shutdown(); + rcu_barrier(); ksmbd_release_inode_hash(); } -- 2.25.1