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 698f3a2ac5aea406ca13fd3e75705bc342d60594..459b957104a8b191c7f3555d353da8df6132eb6e 100644 (file)
--- 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;