FAILED: patch "[PATCH] ping: fix the sk_bound_dev_if match in ping_lookup" failed to apply to 4.9-stable tree

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2afc3b5a31f9edf3ef0f374f5d70610c79c93a42 Mon Sep 17 00:00:00 2001
From: Xin Long <[email protected]>
Date: Sat, 22 Jan 2022 06:40:56 -0500
Subject: [PATCH] ping: fix the sk_bound_dev_if match in ping_lookup

When 'ping' changes to use PING socket instead of RAW socket by:

   # sysctl -w net.ipv4.ping_group_range="0 100"

the selftests 'router_broadcast.sh' will fail, as such command

  # ip vrf exec vrf-h1 ping -I veth0 198.51.100.255 -b

can't receive the response skb by the PING socket. It's caused by mismatch of sk_bound_dev_if and dif in ping_rcv() when looking up the PING socket, as dif is vrf-h1 if dif's master was set to vrf-h1.

This patch is to fix this regression by also checking the sk_bound_dev_if against sdif so that the packets can stil be received even if the socket is not bound to the vrf device but to the real iif.

index 0e56df3a45e2..bcf7bc71cb56 100644
@@ -220,7 +220,8 @@ static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident)
 			continue;
 		}
 
-		if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)
+		if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif &&
+		    sk->sk_bound_dev_if != inet_sdif(skb))
 			continue;
 
 		sock_hold(sk);