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.

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>

1 files changed, 2 insertions, 0 deletions

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 57f7c9804139..85a02a75ad83 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -217,6 +217,8 @@ 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)