[PATCH 4.4 019/137] media: flexcop-usb: fix NULL-ptr deref in flexcop_usb_transfer_init()

Greg Kroah-Hartman
2020-01-02T22:34:31Z

From: Yang Yingliang <yangyingliang@huawei.com>

[ Upstream commit 649cd16c438f51d4cd777e71ca1f47f6e0c5e65d ]

If usb_set_interface() failed, iface->cur_altsetting will
not be assigned and it will be used in flexcop_usb_transfer_init()
It may lead a NULL pointer dereference.

Check usb_set_interface() return value in flexcop_usb_init()
and return failed to avoid using this NULL pointer.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/usb/b2c2/flexcop-usb.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/b2c2/flexcop-usb.c b/drivers/media/usb/b2c2/flexcop-usb.c
index 83d3a5cf272f..932fa31e0624 100644
--- a/drivers/media/usb/b2c2/flexcop-usb.c
+++ b/drivers/media/usb/b2c2/flexcop-usb.c
@@ -474,7 +474,13 @@ urb_error:
static int flexcop_usb_init(struct flexcop_usb *fc_usb)
{
/* use the alternate setting with the larges buffer */
- usb_set_interface(fc_usb->udev,0,1);
+ int ret = usb_set_interface(fc_usb->udev, 0, 1);
+
+ if (ret) {
+ err("set interface failed.");
+ return ret;
+ }
+
switch (fc_usb->udev->speed) {
case USB_SPEED_LOW:
err("cannot handle USB speed because it is too slow.");
--
2.20.1