From: David S. Miller <davem@davemloft.net>
Date: Sat, 2 May 2015 02:02:47 +0000 (-0400)
Subject: ipv4: Missing sk_nulls_node_init() in ping_unhash().
X-Git-Tag: firefly_0821_release~4090^2~12
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=eaa478ab44cd84a788dee5f77ef3171ce83d04cf;p=firefly-linux-kernel-4.4.55.git

ipv4: Missing sk_nulls_node_init() in ping_unhash().

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 <torvalds@linux-foundation.org>
Reported-by: Wen Xu <hotdog3645@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Bug: 20770158
Change-Id: I944eb20fddea190892c2da681d934801d268096b
---

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 8642f0044dfa..32d894fa1071 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;