linux-kernel - Re: [PATCH] tty: serial: return appropriate error on failure

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Date:   Wed, 8 Dec 2021 06:44:53 +0100
From:   Jiri Slaby <jirislaby@...nel.org>
To:     Vihas Mak <makvihas@...il.com>, gregkh@...uxfoundation.org
Cc:     linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] tty: serial: return appropriate error on failure

On 07. 12. 21, 23:17, Vihas Mak wrote:
> when a user with CAP_SYS_ADMIN disabled calls ioctl (TIOCSSERIAL),
> uart_set_info() returns 0 instead of -EPERM and the user remains unware
> about what went wrong. Fix this.
> 
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215205
> 
> Signed-off-by: Vihas Mak <makvihas@...il.com>
> ---
>   drivers/tty/serial/serial_core.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> index 61e3dd022..c204bdecc 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -960,7 +960,7 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
>   		uport->fifosize = new_info->xmit_fifo_size;
>   
>    check_and_exit:
> -	retval = 0;
> +	retval = retval < 0 ? retval : 0;

This is wrong IMO. See:
https://bugzilla.kernel.org/show_bug.cgi?id=215205#c1

>   	if (uport->type == PORT_UNKNOWN)
>   		goto exit;
>   	if (tty_port_initialized(port)) {
> 


-- 
js
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