net/ping: handle protocol mismatching scenario

ping_lookup() may return a wrong sock if sk_buff's and sock's protocols
dont' match. For example, sk_buff's protocol is ETH_P_IPV6, but sock's
sk_family is AF_INET, in that case, if sk->sk_bound_dev_if is zero, a wrong
sock will be returned.
the fix is to "continue" the searching, if no matching, return NULL.

[cherry-pick of net 91a0b603469069cdcce4d572b7525ffc9fd352a6]

Bug: 18512516
Change-Id: I520223ce53c0d4e155c37d6b65a03489cc7fd494
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: netdev@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Jane Zhou <a17711@motorola.com>
Signed-off-by: Yiwei Zhao <gbjc64@motorola.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index b83d82951cad63a8172ce85f4c44464d5352bd68..634994af080cbc3560ac6215ef8566c23b418315 100644 (file)
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -214,6 +214,8 @@ static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident)
                                             &ipv6_hdr(skb)->daddr))
                                continue;
 #endif
+               } else {
+                       continue;
                }
 
                if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)