On Fri, Aug 26, 2022 at 5:51 PM Ilpo Järvinen
<ilpo.jarvinen@xxxxxxxxxxxxxxx> wrote:
>
> Due to the padding fields, the copying will need to a bit more than
> usual.
>
> Move padding clearing into the helper that copies back to userspace.
If you agree on the below and address as suggested,
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
> ---
> drivers/tty/serial/serial_core.c | 41 +++++++++++++++++++++-----------
> 1 file changed, 27 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> index 9c1bf36b7a93..6d57cfdeda9d 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -1375,10 +1375,6 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4
> rs485->flags &= supported_flags;
>
> uart_sanitize_serial_rs485_delays(port, rs485);
> -
> - /* Return clean padding area to userspace */
> - memset(rs485->padding0, 0, sizeof(rs485->padding0));
> - memset(rs485->padding1, 0, sizeof(rs485->padding1));
> }
>
> static void uart_set_rs485_termination(struct uart_port *port,
> @@ -1407,6 +1403,28 @@ int uart_rs485_config(struct uart_port *port)
> }
> EXPORT_SYMBOL_GPL(uart_rs485_config);
>
> +static int user_rs485_to_kernel_serial_rs485(struct serial_rs485 *rs485,
> + const struct serial_rs485 __user *rs485_user)
What about
serial_rs485_from_user()
> +{
> + if (copy_from_user(rs485, rs485_user, sizeof(*rs485)))
> + return -EFAULT;
> +
> + return 0;
> +}
> +
> +static int kernel_serial_rs485_to_user_rs485(struct serial_rs485 __user *rs485_user,
> + struct serial_rs485 *rs485)
serial_rs485_to_user()
?
> +{
> + /* Return clean padding area to userspace */
> + memset(rs485->padding0, 0, sizeof(rs485->padding0));
> + memset(rs485->padding1, 0, sizeof(rs485->padding1));
> +
> + if (copy_to_user(rs485_user, rs485, sizeof(*rs485)))
> + return -EFAULT;
> +
> + return 0;
> +}
> +
> static int uart_get_rs485_config(struct uart_port *port,
> struct serial_rs485 __user *rs485_user)
> {
> @@ -1417,10 +1435,7 @@ static int uart_get_rs485_config(struct uart_port *port,
> rs485 = port->rs485;
> spin_unlock_irqrestore(&port->lock, flags);
>
> - if (copy_to_user(rs485_user, &rs485, sizeof(rs485)))
> - return -EFAULT;
> -
> - return 0;
> + return kernel_serial_rs485_to_user_rs485(rs485_user, &rs485);
> }
>
> static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
> @@ -1433,8 +1448,9 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
> if (!port->rs485_config)
> return -ENOTTY;
>
> - if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
> - return -EFAULT;
> + ret = user_rs485_to_kernel_serial_rs485(&rs485, rs485_user);
> + if (ret)
> + return ret;
>
> ret = uart_check_rs485_flags(port, &rs485);
> if (ret)
> @@ -1450,10 +1466,7 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
> if (ret)
> return ret;
>
> - if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
> - return -EFAULT;
> -
> - return 0;
> + return kernel_serial_rs485_to_user_rs485(rs485_user, &port->rs485);
> }
>
> static int uart_get_iso7816_config(struct uart_port *port,
> --
> 2.30.2
>
--
With Best Regards,
Andy Shevchenko
