Commit b91cfb25 authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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tty: mxser: fix TIOCSSERIAL permission check 



Changing the port type and closing_wait parameter are privileged
operations so make sure to return -EPERM if a regular user tries to
change them.

Note that the closing_wait parameter would not actually have been
changed but the return value did not indicate that.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407102334.32361-15-johan@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent be6cf583

drivers/tty/mxser.c

+4 −3
Original line number Diff line number Diff line
@@ -1270,6 +1270,7 @@ static int mxser_set_serial_info(struct tty_struct *tty, 
	if (!capable(CAP_SYS_ADMIN)) {

		if ((ss->baud_base != info->baud_base) ||

				(close_delay != info->port.close_delay) ||

				(closing_wait != info->port.closing_wait) ||

				((ss->flags & ~ASYNC_USR_MASK) != (info->port.flags & ~ASYNC_USR_MASK))) {

			mutex_unlock(&port->mutex);

			return -EPERM;
@@ -1296,11 +1297,11 @@ static int mxser_set_serial_info(struct tty_struct *tty, 
			baud = ss->baud_base / ss->custom_divisor;

			tty_encode_baud_rate(tty, baud, baud);

		}

	}



		info->type = ss->type;



		process_txrx_fifo(info);

	}



	if (tty_port_initialized(port)) {

		if (flags != (port->flags & ASYNC_SPD_MASK)) {