xfrm: check for xdo_dev_state_free

The current XFRM code assumes that we've implemented the
xdo_dev_state_free() callback, even if it is meaningless to the driver.
This patch adds a check for it before calling, as done in other APIs,
to prevent a NULL function pointer kernel crash.

Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 357764a..079ea94 100644 (file)
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1933,7 +1933,8 @@ static inline void xfrm_dev_state_free(struct xfrm_state *x)
         struct net_device *dev = xso->dev;
 
        if (dev && dev->xfrmdev_ops) {
-               dev->xfrmdev_ops->xdo_dev_state_free(x);
+               if (dev->xfrmdev_ops->xdo_dev_state_free)
+                       dev->xfrmdev_ops->xdo_dev_state_free(x);
                xso->dev = NULL;
                dev_put(dev);
        }