[PATCH] Bluetooth: hci_ldisc: Add NULL check for tty set_termios operation

[Myungho Jung]

set_termios should not be NULL so return EOPNOTSUPP if tty driver does
not support the operation.

Reported-by: syzbot+a950165cbb86bdd023a4@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Myungho Jung <mhjungk@xxxxxxxxx>
---
 drivers/bluetooth/hci_ldisc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index fbf7b4df23ab..44ac2e9494cc 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -474,10 +474,10 @@ static int hci_uart_tty_open(struct tty_struct *tty)
 
 	BT_DBG("tty %p", tty);
 
-	/* Error if the tty has no write op instead of leaving an exploitable
-	 * hole
+	/* Error if the tty has no write or set_termios op instead of leaving an
+	 * exploitable hole
 	 */
-	if (tty->ops->write == NULL)
+	if (tty->ops->write == NULL || tty->ops->set_termios == NULL)
 		return -EOPNOTSUPP;
 
 	hu = kzalloc(sizeof(struct hci_uart), GFP_KERNEL);
-- 
2.17.1