[PATCH] usb: usbfs: fix crash in check_ctrlrecip()->usb_find_alt_setting()

[Vladis Dronov]

ps->dev->actconfig can be NULL and cause NULL-deref in usb_find_alt_setting()
before c9a4cb204e9e. fix this anyway by checking that ps->dev->actconfig is not
NULL, so usb_find_alt_setting() is not called with a known-bad argument.

Signed-off-by: Vladis Dronov <vdronov@xxxxxxxxxx>
Reported-by: syzbot+19c3aaef85a89d451eac@xxxxxxxxxxxxxxxxxxxxxxxxx
---
 drivers/usb/core/devio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 6ce77b33da61..26047620b003 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -824,7 +824,7 @@ static int check_ctrlrecip(struct usb_dev_state *ps, unsigned int requesttype,
 	 * class specification, which we always want to allow as it is used
 	 * to query things like ink level, etc.
 	 */
-	if (requesttype == 0xa1 && request == 0) {
+	if (requesttype == 0xa1 && request == 0 && ps->dev->actconfig) {
 		alt_setting = usb_find_alt_setting(ps->dev->actconfig,
 						   index >> 8, index & 0xff);
 		if (alt_setting
-- 
2.14.4