Commit 2104eb28 authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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staging: fwserial: fix TIOCSSERIAL permission check 



Changing the port close-delay parameter is a privileged operation so
make sure to return -EPERM if a regular user tries to change it.

Fixes: 7355ba34 ("staging: fwserial: Add TTY-over-Firewire serial driver")
Cc: stable@vger.kernel.org      # 3.8
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407102334.32361-3-johan@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7a3791af

drivers/staging/fwserial/fwserial.c

+6 −2
Original line number Diff line number Diff line
@@ -1232,20 +1232,24 @@ static int set_serial_info(struct tty_struct *tty, 
			   struct serial_struct *ss)

{

	struct fwtty_port *port = tty->driver_data;

	unsigned int cdelay;



	if (ss->irq != 0 || ss->port != 0 || ss->custom_divisor != 0 ||

	    ss->baud_base != 400000000)

		return -EPERM;



	cdelay = msecs_to_jiffies(ss->close_delay * 10);



	mutex_lock(&port->port.mutex);

	if (!capable(CAP_SYS_ADMIN)) {

		if (((ss->flags & ~ASYNC_USR_MASK) !=

		if (cdelay != port->port.close_delay ||

		    ((ss->flags & ~ASYNC_USR_MASK) !=

		     (port->port.flags & ~ASYNC_USR_MASK))) {

			mutex_unlock(&port->port.mutex);

			return -EPERM;

		}

	}

	port->port.close_delay = msecs_to_jiffies(ss->close_delay * 10);

	port->port.close_delay = cdelay;

	mutex_unlock(&port->port.mutex);



	return 0;