[PATCH 5.12 013/677] USB: serial: ti_usb_3410_5052: fix TIOCSSERIAL permission check

[Greg Kroah-Hartman]

From: Johan Hovold <johan@xxxxxxxxxx>

commit d370c90dcd64e427a79a093a070117a1571d4cd8 upstream.

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

Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/usb/serial/ti_usb_3410_5052.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/usb/serial/ti_usb_3410_5052.c
+++ b/drivers/usb/serial/ti_usb_3410_5052.c
@@ -1418,14 +1418,19 @@ static int ti_set_serial_info(struct tty
 	struct serial_struct *ss)
 {
 	struct usb_serial_port *port = tty->driver_data;
-	struct ti_port *tport = usb_get_serial_port_data(port);
+	struct tty_port *tport = &port->port;
 	unsigned cwait;
 
 	cwait = ss->closing_wait;
 	if (cwait != ASYNC_CLOSING_WAIT_NONE)
 		cwait = msecs_to_jiffies(10 * ss->closing_wait);
 
-	tport->tp_port->port.closing_wait = cwait;
+	if (!capable(CAP_SYS_ADMIN)) {
+		if (cwait != tport->closing_wait)
+			return -EPERM;
+	}
+
+	tport->closing_wait = cwait;
 
 	return 0;
 }