[PATCH 3.16 195/366] xfrm: free skb if nlsk pointer is NULL

Ben Hutchings
2018-11-11T20:20:29Z

From: Florian Westphal <fw@strlen.de>

commit 86126b77dcd551ce223e7293bb55854e3df05646 upstream.

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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
net/xfrm/xfrm_user.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -959,10 +959,12 @@ static inline int xfrm_nlmsg_multicast(s
{
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 size_t xfrm_spdinfo_msgsize(void)