Re: [PATCH] conntrack_tcp: Reset the max ACK flag on SYN in ignore state

[Florian Westphal <fw@strlen.de>]

Ali Abdallah <ali.abdallah@suse.com> wrote:
> In ignore state, we let SYN goes in original, the server might respond
> with RST/ACK, and that RST packet is erroneously dropped because of the
> flag IP_CT_TCP_FLAG_MAXACK_SET being already set.
> ---
>  net/netfilter/nf_conntrack_proto_tcp.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
> index ec23330687a5..891a66e35afd 100644
> --- a/net/netfilter/nf_conntrack_proto_tcp.c
> +++ b/net/netfilter/nf_conntrack_proto_tcp.c
> @@ -963,6 +963,9 @@ int nf_conntrack_tcp_packet(struct nf_conn *ct,
>  
>  			ct->proto.tcp.last_flags =
>  			ct->proto.tcp.last_wscale = 0;
> +			/* Reset the max ack flag so in case the server replies
> +			 * with RST/ACK it will be marked as an invalid rst */

"not be marked"?

> +			ct->proto.tcp.seen[dir].flags &= ~IP_CT_TCP_FLAG_MAXACK_SET;
>  			tcp_options(skb, dataoff, th, &seen);
>  			if (seen.flags & IP_CT_TCP_FLAG_WINDOW_SCALE) {