rtl8187: fix use after free on failure path in rtl8187_probe()

If allocation of io_dmabuf fails, rtl8187_probe() calls usb_put_dev(udev)
while usb_get_dev(udev) is not called yet. As a result refcnt is decremented
incorrectly and usb_dev can be used after memory deallocation.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/rtl818x/rtl8187/dev.c b/drivers/net/wireless/rtl818x/rtl8187/dev.c
index 2c79bcc..0ca17cd 100644 (file)
--- a/drivers/net/wireless/rtl818x/rtl8187/dev.c
+++ b/drivers/net/wireless/rtl818x/rtl8187/dev.c
@@ -1636,10 +1636,10 @@ static int rtl8187_probe(struct usb_interface *intf,
 
  err_free_dmabuf:
        kfree(priv->io_dmabuf);
- err_free_dev:
-       ieee80211_free_hw(dev);
        usb_set_intfdata(intf, NULL);
        usb_put_dev(udev);
+ err_free_dev:
+       ieee80211_free_hw(dev);
        return err;
 }