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

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Date:   Wed,  7 Apr 2021 12:39:15 +0200
From:   Johan Hovold <johan@...nel.org>
To:     Johan Hovold <johan@...nel.org>
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org
Subject: [PATCH 14/24] USB: serial: ti_usb_3410_5052: fix TIOCSSERIAL permission check

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@...r.kernel.org
Signed-off-by: Johan Hovold <johan@...nel.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