From: Sean Heelan <seanheelan@gmail.com>
Date: Mon, 21 Apr 2025 15:39:29 +0000 (+0000)
Subject: ksmbd: fix use-after-free in session logoff
X-Git-Tag: v6.15-rc5~31^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2fc9feff45d92a92cd5f96487655d5be23fb7e2b;p=thirdparty%2Flinux.git

ksmbd: fix use-after-free in session logoff

The sess->user object can currently be in use by another thread, for
example if another connection has sent a session setup request to
bind to the session being free'd. The handler for that connection could
be in the smb2_sess_setup function which makes use of sess->user.

Cc: stable@vger.kernel.org
Signed-off-by: Sean Heelan <seanheelan@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
---

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index acc05657cfc72..46aa082457424 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -2249,10 +2249,6 @@ int smb2_session_logoff(struct ksmbd_work *work)
 	sess->state = SMB2_SESSION_EXPIRED;
 	up_write(&conn->session_lock);
 
-	if (sess->user) {
-		ksmbd_free_user(sess->user);
-		sess->user = NULL;
-	}
 	ksmbd_all_conn_set_status(sess_id, KSMBD_SESS_NEED_SETUP);
 
 	rsp->StructureSize = cpu_to_le16(4);