[PATCH 14/24] USB: serial: ti_usb_3410_5052: fix TIOCSSERIAL permission check

Johan Hovold
2021-04-07T10:40:50Z

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@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/usb/serial/ti_usb_3410_5052.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/serial/ti_usb_3410_5052.c b/drivers/usb/serial/ti_usb_3410_5052.c
index 4b497c1e850b..bb50098a0ce6 100644
--- 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 *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;
}
--
2.26.3