[PATCH 5.3 130/166] hso: fix NULL-deref on tty open

Greg Kroah-Hartman
2019-10-06T17:51:59Z

From: Johan Hovold <johan@kernel.org>

[ Upstream commit 8353da9fa69722b54cba82b2ec740afd3d438748 ]

Fix NULL-pointer dereference on tty open due to a failure to handle a
missing interrupt-in endpoint when probing modem ports:

BUG: kernel NULL pointer dereference, address: 0000000000000006
...
RIP: 0010:tiocmget_submit_urb+0x1c/0xe0 [hso]
...
Call Trace:
hso_start_serial_device+0xdc/0x140 [hso]
hso_serial_open+0x118/0x1b0 [hso]
tty_open+0xf1/0x490

Fixes: 542f54823614 ("tty: Modem functions for the HSO driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/usb/hso.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -2620,14 +2620,18 @@ static struct hso_device *hso_create_bul
*/
if (serial->tiocmget) {
tiocmget = serial->tiocmget;
+ tiocmget->endp = hso_get_ep(interface,
+ USB_ENDPOINT_XFER_INT,
+ USB_DIR_IN);
+ if (!tiocmget->endp) {
+ dev_err(&interface->dev, "Failed to find INT IN ep\n");
+ goto exit;
+ }
+
tiocmget->urb = usb_alloc_urb(0, GFP_KERNEL);
if (tiocmget->urb) {
mutex_init(&tiocmget->mutex);
init_waitqueue_head(&tiocmget->waitq);
- tiocmget->endp = hso_get_ep(
- interface,
- USB_ENDPOINT_XFER_INT,
- USB_DIR_IN);
} else
hso_free_tiomget(serial);
}