[3.16.y-ckt stable] Patch "ipv4: Missing sk_nulls_node_init() in ping_unhash()." has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    ipv4: Missing sk_nulls_node_init() in ping_unhash().

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt11.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From d85e004953219aabe45c6af47283a098f1426fc8 Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem at davemloft.net>
Date: Fri, 1 May 2015 22:02:47 -0400
Subject: ipv4: Missing sk_nulls_node_init() in ping_unhash().

commit a134f083e79fb4c3d0a925691e732c56911b4326 upstream.

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 at linux-foundation.org>
Reported-by: Wen Xu <hotdog3645 at gmail.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/ipv4/ping.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 45d5bc0ad86c..30d0a64be413 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -158,6 +158,7 @@ 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;