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 <[email protected]>

---
For a discussion about this patch and the underlying problem, see the mails with as subject "[PATCH] brcmfmac: unlink URB when request timed out".

 drivers/net/wireless/brcm80211/brcmfmac/usb.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

drivers/net/wireless/brcm80211/brcmfmac/usb.c +4 -2

index 5265aa7..4572def 100644
@@ -738,10 +738,12 @@ 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);