Subject: [PATCH] ipv4: Missing sk_nulls_node_init() in ping_unhash().

From: "David S. Miller" <[email-masked]>
Date: Fri, 1 May 2015 22:02:47 -0400

[ Upstream commit a134f083e79fb4c3d0a925691e732c56911b4326 ]

If we don't do that, then the poison value is left in the ->pprev
backlink.

This can cause crashes if we do a disconnect, followed by a connect().

Tested-by: Linus Torvalds <[email-masked]>
Reported-by: Wen Xu <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/ipv4/ping.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index a9f8e66..54012b8 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -154,6 +154,7 @@ void ping_unhash(struct sock *sk)
 	if (sk_hashed(sk)) {
 		write_lock_bh(&ping_table.lock);
 		hlist_nulls_del(&sk->sk_nulls_node);
+		sk_nulls_node_init(&sk->sk_nulls_node);
 		sock_put(sk);
 		isk->inet_num = 0;
 		isk->inet_sport = 0;
-- 
2.3.6