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~3679^2~472
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=firefly-linux-kernel-4.4.55.git;a=commitdiff_plain;h=cf30cd6bbc0c82854e0b5551e57ee02d001e61db

ipv4: Missing sk_nulls_node_init() in ping_unhash().

[ 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 <torvalds@linux-foundation.org>
Reported-by: Wen Xu <hotdog3645@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 698f3a2ac5ae..459b957104a8 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -139,6 +139,7 @@ static void ping_v4_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;