diff mbox series

[5/6] serial: core: make sure RS485 is cannot be enabled when it is not supported

Message ID 20230928221246.13689-6-LinoSanfilippo@gmx.de
State New
Headers
Series Fixes and improvements for RS485 |

Commit Message

Lino Sanfilippo Sept. 28, 2023, 10:12 p.m. UTC 
  From: Lino Sanfilippo <l.sanfilippo@kunbus.com>

Some uart drivers specify a rs485_config() function and then decide later
to disable RS485 support for some reason (e.g. imx and ar933).

In these cases userspace may be able to activate RS485 via TIOCSRS485
nevertheless, since in uart_set_rs485_config() an existing rs485_config()
function indicates that RS485 is supported.

Make sure that this is not longer possible by checking the uarts
rs485_supported.flags instead and bailing out if SER_RS485_ENABLED is not
set.

Furthermore instead of returning an empty structure return -ENOTTY if the
RS485 configuration is requested via TIOCGRS485 but RS485 is not supported.

Cc: stable@vger.kernel.org
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
---
 drivers/tty/serial/serial_core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Hugo Villeneuve Sept. 29, 2023, 12:17 p.m. UTC | #1 
Hi,
remove superfluous "is" after RS485 in patch title.

Hugo.



On Fri, 29 Sep 2023 00:12:45 +0200
Lino Sanfilippo <LinoSanfilippo@gmx.de> wrote:

> From: Lino Sanfilippo <l.sanfilippo@kunbus.com>
> 
> Some uart drivers specify a rs485_config() function and then decide later
> to disable RS485 support for some reason (e.g. imx and ar933).
> 
> In these cases userspace may be able to activate RS485 via TIOCSRS485
> nevertheless, since in uart_set_rs485_config() an existing rs485_config()
> function indicates that RS485 is supported.
> 
> Make sure that this is not longer possible by checking the uarts
> rs485_supported.flags instead and bailing out if SER_RS485_ENABLED is not
> set.
> 
> Furthermore instead of returning an empty structure return -ENOTTY if the
> RS485 configuration is requested via TIOCGRS485 but RS485 is not supported.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
> ---
>  drivers/tty/serial/serial_core.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> index f4feebf8200f..dca09877fabc 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -1432,6 +1432,9 @@ static int uart_get_rs485_config(struct uart_port *port,
>  	unsigned long flags;
>  	struct serial_rs485 aux;
>  
> +	if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
> +		return -ENOTTY;
> +
>  	spin_lock_irqsave(&port->lock, flags);
>  	aux = port->rs485;
>  	spin_unlock_irqrestore(&port->lock, flags);
> @@ -1449,7 +1452,7 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
>  	int ret;
>  	unsigned long flags;
>  
> -	if (!port->rs485_config)
> +	if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
>  		return -ENOTTY;
>  
>  	if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
> -- 
> 2.40.1
>
Lino Sanfilippo Sept. 29, 2023, 12:25 p.m. UTC | #2 
Hi,

On 29.09.23 14:17, Hugo Villeneuve wrote:
> Hi,
> remove superfluous "is" after RS485 in patch title.
>
> Hugo.
>

Indeed, I will fix this, thanks!

BR,
Lino
diff mbox series

Patch

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index f4feebf8200f..dca09877fabc 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1432,6 +1432,9 @@  static int uart_get_rs485_config(struct uart_port *port,
 	unsigned long flags;
 	struct serial_rs485 aux;
 
+	if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
+		return -ENOTTY;
+
 	spin_lock_irqsave(&port->lock, flags);
 	aux = port->rs485;
 	spin_unlock_irqrestore(&port->lock, flags);
@@ -1449,7 +1452,7 @@  static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
 	int ret;
 	unsigned long flags;
 
-	if (!port->rs485_config)
+	if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
 		return -ENOTTY;
 
 	if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))