Re: Back-porting request

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Jul 29, 2019 at 11:42:34AM -0400, Stephen Suryaputra wrote:
> Hello,
> 
> I'm requesting this commit to be back-ported to v4.14:
> ---
> commit 5b18f1289808fee5d04a7e6ecf200189f41a4db6
> Author: Stephen Suryaputra <ssuryaextr@gmail.com>
> Date:   Wed Jun 26 02:21:16 2019 -0400
> 
>     ipv4: reset rt_iif for recirculated mcast/bcast out pkts
> 
>     Multicast or broadcast egress packets have rt_iif set to the oif. These
>     packets might be recirculated back as input and lookup to the raw
>     sockets may fail because they are bound to the incoming interface
>     (skb_iif). If rt_iif is not zero, during the lookup, inet_iif() function
>     returns rt_iif instead of skb_iif. Hence, the lookup fails.
> 
>     v2: Make it non vrf specific (David Ahern). Reword the changelog to
>         reflect it.
>     Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
>     Reviewed-by: David Ahern <dsahern@gmail.com>
>     Signed-off-by: David S. Miller <davem@davemloft.net>
> ---
> 
> We found the issue in that release and the above commit is on
> linux-stable. On the discussion behind this commit, please see:
> https://www.spinics.net/lists/netdev/msg581045.html
> 
> I think after the following diff is needed on top of the above commit
> for v4.14:
> 
> ---
> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
> index 4d85a4fdfdb0..ad2718c1624e 100644
> --- a/net/ipv4/route.c
> +++ b/net/ipv4/route.c
> @@ -1623,11 +1623,8 @@ struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
>  		new_rt->rt_iif = rt->rt_iif;
>  		new_rt->rt_pmtu = rt->rt_pmtu;
>  		new_rt->rt_mtu_locked = rt->rt_mtu_locked;
> -		new_rt->rt_gw_family = rt->rt_gw_family;
> -		if (rt->rt_gw_family == AF_INET)
> -			new_rt->rt_gw4 = rt->rt_gw4;
> -		else if (rt->rt_gw_family == AF_INET6)
> -			new_rt->rt_gw6 = rt->rt_gw6;
> +		new_rt->rt_gateway = rt->rt_gateway;
> +		new_rt->rt_table_id = rt->rt_table_id;
>  		INIT_LIST_HEAD(&new_rt->rt_uncached);
>  
>  		new_rt->dst.flags |= DST_HOST;
> ---
> 
> Thank you,

For networking patches to be applied to the stable kernel tree(s),
please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

There is a section for how to do this for networking patches as they are
accepted a bit differently from other patches.

thanks,

greg k-h