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 stable@vger.kernel.org.

thanks,

greg k-h

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

From 35a79e64de29e8d57a5989aac57611c0cd29e13e Mon Sep 17 00:00:00 2001 From: Xin Long lucien.xin@gmail.com Date: Wed, 16 Feb 2022 00:20:52 -0500 Subject: [PATCH] ping: fix the dif and sdif check in ping_lookup

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

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

There is another regression caused when matching sk_bound_dev_if and dif, RAW socket is using inet_iif() while PING socket lookup is using skb->dev->ifindex, the cmd below fails due to this:

# ip link add dummy0 type dummy # ip link set dummy0 up # ip addr add 192.168.111.1/24 dev dummy0 # ping -I dummy0 192.168.111.1 -c1

The issue was also reported on:

https://github.com/iputils/iputils/issues/104

But fixed in iputils in a wrong way by not binding to device when destination IP is on device, and it will cause some of kselftests to fail, as Jianlin noticed.

This patch is to use inet(6)_iif and inet(6)_sdif to get dif and sdif for PING socket, and keep consistent with RAW socket.

Fixes: c319b4d76b9e ("net: ipv4: add IPPROTO_ICMP socket kind") Reported-by: Jianlin Shi jishi@redhat.com Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c index bcf7bc71cb56..3a5994b50571 100644 --- a/net/ipv4/ping.c +++ b/net/ipv4/ping.c @@ -172,16 +172,23 @@ static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident) struct sock *sk = NULL; struct inet_sock *isk; struct hlist_nulls_node *hnode; - int dif = skb->dev->ifindex; + int dif, sdif;

if (skb->protocol == htons(ETH_P_IP)) { + dif = inet_iif(skb); + sdif = inet_sdif(skb); pr_debug("try to find: num = %d, daddr = %pI4, dif = %d\n", (int)ident, &ip_hdr(skb)->daddr, dif); #if IS_ENABLED(CONFIG_IPV6) } else if (skb->protocol == htons(ETH_P_IPV6)) { + dif = inet6_iif(skb); + sdif = inet6_sdif(skb); pr_debug("try to find: num = %d, daddr = %pI6c, dif = %d\n", (int)ident, &ipv6_hdr(skb)->daddr, dif); #endif + } else { + pr_err("ping: protocol(%x) is not supported\n", ntohs(skb->protocol)); + return NULL; }

read_lock_bh(&ping_table.lock); @@ -221,7 +228,7 @@ static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident) }

if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif && - sk->sk_bound_dev_if != inet_sdif(skb)) + sk->sk_bound_dev_if != sdif) continue;

sock_hold(sk);