From: Sean Heelan <seanheelan@gmail.com>
Date: Thu, 27 Nov 2025 16:13:33 +0000 (+0300)
Subject: ksmbd: fix use-after-free in session logoff
X-Git-Tag: v6.1.159~7
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=931dc8a3670f71c45c0b1379ea4e92dafbda1aca;p=thirdparty%2Fkernel%2Fstable.git

ksmbd: fix use-after-free in session logoff

commit 2fc9feff45d92a92cd5f96487655d5be23fb7e2b upstream.

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.

Signed-off-by: Sean Heelan <seanheelan@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Nazar Kalashnikov <sivartiwe@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index e3ea06aab8c1b..5a405706694b3 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -2253,10 +2253,6 @@ 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_NEGOTIATE);
 
 	rsp->StructureSize = cpu_to_le16(4);