[PATCH] ksmbd: fix slab-use-after-free in smb3_preauth_hash_rsp

[Namjae Jeon <linkinjeon@xxxxxxxxxx>]

ksmbd_user_session_put should be called under smb3_preauth_hash_rsp().
It will avoid freeing session before calling smb3_preauth_hash_rsp().

Cc: stable@xxxxxxxxxxxxxxx # v5.15+
Reported-by: Norbert Szetei <norbert@xxxxxxxxxxxx>
Tested-by: Norbert Szetei <norbert@xxxxxxxxxxxx>
Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>

diff --git a/fs/smb/server/server.c b/fs/smb/server/server.c
index 9670c97f14b3..e7f14f8df943 100644
--- a/fs/smb/server/server.c
+++ b/fs/smb/server/server.c
@@ -238,11 +238,11 @@ static void __handle_ksmbd_work(struct ksmbd_work *work,
 	} while (is_chained == true);
 
 send:
-	if (work->sess)
-		ksmbd_user_session_put(work->sess);
 	if (work->tcon)
 		ksmbd_tree_connect_put(work->tcon);
 	smb3_preauth_hash_rsp(work);
+	if (work->sess)
+		ksmbd_user_session_put(work->sess);
 	if (work->sess && work->sess->enc && work->encrypted &&
 	    conn->ops->encrypt_resp) {
 		rc = conn->ops->encrypt_resp(work);