Re: [PATCH v2] Bluetooth: Add NULL check for tiocmget() and tiocmset()

From: Johan Hovold <johan@kernel.org>
To: Myungho Jung <mhjungk@gmail.com>
Cc: Marcel Holtmann <marcel@holtmann.org>,
	Johan Hedberg <johan.hedberg@gmail.com>,
	linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] Bluetooth: Add NULL check for tiocmget() and tiocmset()
Date: Thu, 31 Jan 2019 16:40:00 +0100	[thread overview]
Message-ID: <20190131154000.GU3691@localhost> (raw)
In-Reply-To: <20190130053925.GA26699@myunghoj-Precision-5530>

On Tue, Jan 29, 2019 at 09:39:28PM -0800, Myungho Jung wrote:
> tiocmget() and tiocmset() operations are optional and some tty drivers
> like pty miss the operations. We need NULL check to prevent from
> dereference.
> 
> Signed-off-by: Myungho Jung <mhjungk@gmail.com>
> ---
>  drivers/bluetooth/hci_ath.c   | 6 ++++++
>  drivers/bluetooth/hci_ldisc.c | 4 ++++
>  2 files changed, 10 insertions(+)

Ah, you had already submitted a v2.

I still suggest splitting this one in two patches and that you add a
Fixes and stable tag to each so that they both get backported to stable.

Also, when resubmitting, make sure to include a short changelog here
below the cut-off line (---).

> 
> diff --git a/drivers/bluetooth/hci_ath.c b/drivers/bluetooth/hci_ath.c
> index d568fbd94d6c..fb9f6323a911 100644
> --- a/drivers/bluetooth/hci_ath.c
> +++ b/drivers/bluetooth/hci_ath.c
> @@ -185,8 +185,14 @@ static int ath_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr)
>  
>  static int ath_setup(struct hci_uart *hu)
>  {
> +	struct tty_struct *tty = hu->tty;
> +
>  	BT_DBG("hu %p", hu);
>  
> +	/* tty driver should support operations to set RTS */
> +	if (!tty->driver->ops->tiocmget || !tty->driver->ops->tiocmset)
> +		return -EOPNOTSUPP;

-ENODEV might be more appropriate.

Johan