xfrm: free skb if nlsk pointer is NULL

nlmsg_multicast() always frees the skb, so in case we cannot call
it we must do that ourselves.

Fixes: 21ee543edc0dea ("xfrm: fix race between netns cleanup and state expire notification")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 1e50b70ad668068235c9054f5b0c9ff0d938d07f..33878e6e0d0a01cdc5da8ab20bdb92d0d93e056d 100644 (file)
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1025,10 +1025,12 @@ static inline int xfrm_nlmsg_multicast(struct net *net, struct sk_buff *skb,
 {
        struct sock *nlsk = rcu_dereference(net->xfrm.nlsk);
 
-       if (nlsk)
-               return nlmsg_multicast(nlsk, skb, pid, group, GFP_ATOMIC);
-       else
-               return -1;
+       if (!nlsk) {
+               kfree_skb(skb);
+               return -EPIPE;
+       }
+
+       return nlmsg_multicast(nlsk, skb, pid, group, GFP_ATOMIC);
 }
 
 static inline unsigned int xfrm_spdinfo_msgsize(void)