brcmfmac: kill URB when request timed out

Kill the submitted URB in brcmf_usb_dl_cmd if the request timed out. This
assures the URB is never submitted twice. It also prevents a possible
use-after-free of the URB transfer buffer if a timeout occurs.
Signed-off-by: Mathy Vanhoef <vanhoefm@gmail.com>
Acked-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/brcm80211/brcmfmac/usb.c

@@ -669,10 +669,12 @@ static int brcmf_usb_dl_cmd(struct brcmf_usbdev_info *devinfo, u8 cmd,
 		goto finalize;
 	}
 
-	if (!brcmf_usb_ioctl_resp_wait(devinfo))
+	if (!brcmf_usb_ioctl_resp_wait(devinfo)) {
+		usb_kill_urb(devinfo->ctl_urb);
 		ret = -ETIMEDOUT;
-	else
+	} else {
 		memcpy(buffer, tmpbuf, buflen);
+	}
 
 finalize:
 	kfree(tmpbuf);