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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "Florian Westphal" <fw@strlen.de>,
        "Steffen Klassert" <steffen.klassert@secunet.com>
Date:   Sun, 11 Nov 2018 19:49:05 +0000
Message-ID: <lsq.1541965745.623558944@decadent.org.uk>
Subject: [PATCH 3.16 195/366] xfrm: free skb if nlsk pointer is NULL
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3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

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)